A special massage chair motor with optimized stator winding and operation method

Abstract

The application relates to the field of special motors and motor control technology, in particular to a massage chair special-purpose special motor with optimized stator winding and a running method, which comprises core components such as a machine shell, a stator core, a rotor, heat-conducting clamping strips and bimetallic thermal response sheets; motor stator slots are sequentially divided into first and second driving slot groups and first and second heat equalizing slot groups in the circumferential direction, and the outside is in heat conduction cooperation with the heat-conducting clamping strips and the bimetallic thermal response sheets; the core is to break the conventional fixed power-on mode by using the staggered structure of the driving slot group and the heat equalizing slot group, so that the heat is prevented from being long-term accumulated in the same circumferential sector; the application effectively solves the problem of local heat accumulation caused by excessive load of individual coil sections under asymmetric periodic load, and prevents motor insulation aging and torque collapse.

Description

Technical Field

[0001] This invention relates to the field of special motors and motor control technology, specifically to a special motor for massage chairs with optimized stator windings and its operating method. Background Technology

[0002] Under the current operating conditions of special motors in massage chairs, electrical components such as stator windings are often subjected to low-speed heavy loads and periodic impacts. Due to the highly asymmetrical nature of the load, stator coils fixed in a conventional, uniform arrangement often face the challenge of alternating resistance. To cope with the heat generation under complex operating conditions, existing solutions generally adopt a global derating operation or an architecture with added external heat sinks. This passively controls the overall temperature rise by limiting the overall output power of the motor or accelerating surface heat convection. Although this solution has a certain temperature suppression capability under continuous and stable load scenarios, it is highly dependent on global intervention and cannot accurately perceive the internal heat distribution of the stator. When individual coil sections bear excessive current loads, local hot spots are easily formed in specific slots. This passive heat dissipation combined with imprecise control causes heat to accumulate in the same circumferential sector for a long time, which not only causes rapid aging of local insulation but also leads to torque collapse, making it difficult to support continuous and stable output under complex massage rhythms.

[0003] Therefore, how to eliminate local heat accumulation in the stator windings under asymmetrical periodic loads and improve the balance of motor heat distribution and the stability of load switching has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a special motor for massage chairs with optimized stator windings and a method for its operation. The present invention specifically provides the following technical solution:

[0005] A special motor for massage chairs with optimized stator windings includes:

[0006] A housing, wherein a stator core is press-fitted into the housing, and a stator slot is provided on the inner side of the stator core;

[0007] The stator slots are divided into a first driving slot group, a second driving slot group, a first heat dissipation slot group, and a second heat dissipation slot group in a staggered arrangement along the circumferential direction.

[0008] A rotor is installed inside the housing, and the rotor is fixed to the rotating shaft;

[0009] The outer wall of the housing is axially pressed with a heat-conducting clip, and the rear end of the housing is fixed with a rear end cover.

[0010] A bimetallic thermal response sheet is fixed to the outside of the rear end cover, and the bimetallic thermal response sheet is in contact with the rear end face of the thermally conductive clip.

[0011] Preferably: a main torque coil is arranged in the first drive slot group, an auxiliary torque coil is arranged in the second drive slot group, and a temperature rise regulating coil is arranged in the first and second heat spreader groups; a terminal block is fixed on the outside of the rear end cover, and the output terminals of the main torque coil, the auxiliary torque coil, and the temperature rise regulating coil are respectively led to different terminal blocks of the terminal block; a position detection disk is coaxially fixed on the outside of the rear end cover, and Hall elements are arranged on the outer periphery of the position detection disk.

[0012] A method for operating a special motor for massage chairs with optimized stator windings includes:

[0013] S1: Establish an initial working framework, record the dwell time and reverse switching number of the rotating shaft at different angular positions within a complete massage action cycle, and mark the slot group associated with the electric angle region whose dwell time is greater than or equal to the preset dwell time threshold as a high heat risk slot group;

[0014] S2: Identify the difference between continuous load and instantaneous impact, compare the repeatability of dwell time in the same electrical angle region within multiple adjacent action cycles, and monitor the opening and closing rhythm of the bimetallic thermal response sheet to determine the load type;

[0015] S3: Perform winding role reordering. After determining that the high-heat-risk slot group has entered a continuous heat accumulation state, transfer a preset proportion of the drive current in the next operation cycle from the main torque coil to the auxiliary torque coil, and at the same time increase the participation ratio of the temperature rise adjustment coil in the adjacent electric angle interval.

[0016] S4: Perform corner dwell correction, fine-tune the acceleration and deceleration phases within the mechanical action cycle, calculate and output the drift amount of the set rate of change of the relative electrical angle;

[0017] S5: Implement layered current limiting. When the signs of continuous heat accumulation are not relieved, sequentially reduce the continuous conduction ratio of the coil corresponding to the current high-heat-risk slot group, compress the peak energization time of the second drive slot group, and reduce the overall target torque.

[0018] S6: Perform self-recovery determination. When the dwell time of the high-heat-risk tank group decreases and the bimetallic thermal response sheet returns to its initial position, after maintaining the participation ratio of the auxiliary torque coil and the temperature rise adjustment coil for a preset time period, the continuous energization range of the main torque coil is gradually restored.

[0019] Preferably, in step S2, the load type is determined by a load state evaluation function, which is calculated based on the residence time increment and the deflection duration of the bimetallic thermal response sheet.

[0020] Preferably, in S3, the winding rearrangement is controlled by a dynamic energization ratio allocation algorithm. This algorithm adjusts the current setpoint of the auxiliary torque coil in real time based on the heat accumulation coefficient of the high-heat-risk slot group. The algorithm extracts the heat accumulation state deviation between the estimated temperature rise and the target safe temperature rise of the current high-heat-risk slot group, and adjusts the allocation current of the auxiliary torque coil based on the deviation.

[0021] Preferably, S4 includes an offset control strategy based on the mapping relationship between mechanical attitude and stator electrical angle. This offset control strategy is based on a reference angular velocity and a set drift time period, combined with the fine-tuning angular acceleration of the acceleration and deceleration phases, and compensates for a preset safety buffer angle to calculate and output the target offset angle.

[0022] Preferably, in step S5, the target torque control parameters are updated through a multi-level derating algorithm, the estimated heat loss and output target torque within a fixed control cycle are extracted, and the objective function is constructed by combining the torque holding penalty coefficient to output the target torque control parameters.

[0023] Preferably, S6 also includes a state monitoring and smooth transition mechanism. When thermal recovery is detected, the system automatically switches to a slow-release recovery mode and responds according to the following decision tree: if the derating is caused by a short-term impact, the continuous drive configuration of the main torque coil is immediately restored; if the derating is caused by continuous heat accumulation and the bimetallic thermal response sheet recovers to its initial state, the transition state operation is maintained; if the transition state operation time exceeds the set safe time threshold and there is no sign of heat accumulation again, the current limiting of the main torque coil is restored according to a linearly increasing slope; if the bimetallic thermal response sheet deflection is triggered again during the recovery process, the recovery is immediately stopped and the system returns to the previous level current limiting state.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. This invention breaks the fixed energization mode under conventional uniform arrangement by dividing the stator slots into staggered drive slot groups and heat dissipation slot groups in the circumferential direction. This staggered structure avoids the long-term accumulation of heat in the same circumferential sector, effectively solves the problem of local heat accumulation caused by excessive load on individual coil segments under asymmetrical periodic load, and prevents insulation aging and torque collapse.

[0026] 2. This invention constructs an efficient heat conduction and physical sensing path by pressing a heat-conducting strip onto the outer wall of the housing and fixing a bimetallic thermal response sheet in contact with the heat-conducting strip to the rear end cover. This feature can export the heat inside the stator and convert it into the physical deformation of the thermal response sheet, providing a direct basis for distinguishing between instantaneous impact and continuous heat accumulation, and effectively improving the stability of the motor under load switching under complex cycles. Attached Figure Description

[0027] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings, in which several embodiments of this application are shown by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0028] Figure 1 This is a schematic diagram of the overall external structure of the device;

[0029] Figure 2 This is a schematic diagram of the rear cover and its overall connection structure;

[0030] Figure 3 This is a schematic diagram of the internal connection structure of the casing;

[0031] Figure 4 This is a schematic diagram of the stator core structure;

[0032] Figure 5 This is a flowchart of the method of the present invention.

[0033] In the diagram: 1. Housing; 2. Stator core; 3. Stator slot; 4. First drive slot group; 5. Second drive slot group; 6. First heat dissipation slot group; 7. Second heat dissipation slot group; 8. Rotor; 9. Shaft; 10. Thermal clamp; 11. Rear end cover; 12. Bimetallic thermal response sheet; 13. Main torque coil; 14. Auxiliary torque coil; 15. Temperature rise regulating coil; 16. Terminal block; 17. Position detection panel; 18. Hall element. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] Example 1:

[0036] A special motor for massage chairs with optimized stator windings includes:

[0037] Combination Figure 1 and Figure 3 As shown, there is a housing 1, and a stator core 2 is press-fitted inside the housing 1. A stator slot 3 is provided on the inner side of the stator core 2.

[0038] Combination Figure 4As shown, the stator slots 3 are divided into a first drive slot group 4, a second drive slot group 5, a first heat exchanger group 6, and a second heat exchanger group 7 in a staggered arrangement along the circumferential direction.

[0039] A rotor 8 is installed inside the housing 1, and the rotor 8 is fixed to the rotating shaft 9;

[0040] A heat-conducting clip 10 is pressed onto the outer wall of the housing 1 along the axial direction, and a rear end cover 11 is fixed to the rear end of the housing 1.

[0041] Combination Figure 2 As shown, a bimetallic thermal response sheet 12 is fixed to the outside of the rear end cover 11, and the bimetallic thermal response sheet 12 is in contact with the rear end face of the thermally conductive clip 10.

[0042] When existing motors operate under low-speed, heavy-load, and cyclic impact conditions, some coil sections in the stator windings bear excessive current loads, forming local hot spots. Conventional uniform winding arrangements are prone to causing some slots to remain in a state of heat accumulation for a long time under asymmetrical cyclic loads.

[0043] In this embodiment, the housing 1 is a cylindrical steel housing, and the stator core 2 is formed by stacking multiple silicon steel sheets to form a ring. The outer circle of the stator core 2 and the inner circle of the housing 1 are interference fit. The stator slots 3 are divided into a first drive slot group 4, a second drive slot group 5, a first heat dissipation slot group 6 and a second heat dissipation slot group 7 in the circumferential direction. Transition teeth are retained between adjacent slot groups.

[0044] The slot group division allows different windings to assume different energizing roles. Each group of slots is staggered in terms of energizing angle, avoiding heat concentration in the same circumferential sector. The rotor 8 is located inside the stator core 2, and the rotor core 8 is fixed in the middle of the rotating shaft 9. The outer circle of the rotor 8 and the inner circle of the stator maintain a uniform air gap.

[0045] A heat-conducting strip 10 is pressed onto the outer wall of the housing 1 along the axial direction. The heat-conducting strip 10 is made of aluminum alloy strip plate. Its inner side is attached to the outer circle of the housing 1, and its outer side is in contact with the bimetallic thermal response sheet 12. The front end of the heat-conducting strip 10 is close to the high-heat area in the middle of the stator, and the rear end extends to the vicinity of the rear end cover 11, which increases the temperature difference at different axial positions of the housing 1.

[0046] A bimetallic thermal response sheet 12 is fixed to the outside of the rear cover 11. One end of the bimetallic thermal response sheet 12 is pressed onto the support by a screw, and the other end is kept in an openable state with the micro-motion contact. The bottom of the bimetallic thermal response sheet 12 is in contact with the rear end face of the thermally conductive clip 10. Here, the micro-motion contact is fixedly installed on the insulating bracket on the outside of the rear cover 11, and the normally open contact of the micro-motion contact is aligned with the free end of the bimetallic thermal response sheet 12 along the direction of thermal deformation. The leads at both ends of the micro-motion contact are electrically connected to the switch input pins of the controller.

[0047] The bimetallic thermal response sheet 12 is composed of an active layer and a passive layer with different coefficients of thermal expansion. At room temperature, it is in a disconnected gap state with the micro-motion contact. When the heat-conducting clip 10 conducts heat from the middle of the stator to the bimetallic thermal response sheet 12 and exceeds the deformation temperature threshold, its free end is heated and arched outward and deflects, pressing down on the micro-motion contact, thereby realizing the physical closure signal output of the contact electrical circuit. When the winding continues to heat up for a period of time, the bending state of the bimetallic thermal response sheet 12 will remain for a period of time after the short-term impact disappears. This physical memory characteristic provides a basis for distinguishing between instantaneous impact load and continuous heat accumulation load.

[0048] The first drive slot group 4 is equipped with a main torque coil 13, the second drive slot group 5 is equipped with an auxiliary torque coil 14, and the first heat dissipation slot group 6 and the second heat dissipation slot group 7 are equipped with temperature rise regulating coils 15. A terminal block 16 is fixed on the outside of the rear end cover 11, and the output terminals of the main torque coil 13, the auxiliary torque coil 14 and the temperature rise regulating coil 15 are respectively led to different terminal blocks of the terminal block 16. A position detection disk 17 is coaxially fixed on the outside of the rear end cover 11, and Hall elements 18 are arranged on the outer periphery of the position detection disk 17.

[0049] The stator winding is formed by winding insulated copper wire. The main torque coil 13 is arranged in the first drive slot group 4, the auxiliary torque coil 14 is arranged in the second drive slot group 5, and the temperature rise regulating coil 15 is arranged in the first heat-spreading slot group 6 and the second heat-spreading slot group 7. The number of effective conductors per slot of the main torque coil 13 is greater than the number of effective conductors per slot of the temperature rise regulating coil 15. The cross-sectional area of ​​the conductor of the auxiliary torque coil 14 is the same as that of the main torque coil 13, but the pitch is different. The temperature rise regulating coil 15 adopts a segmented transposition winding method so that the input and return segments of the same coil are distributed in different slot groups.

[0050] This segmented repositioning winding method allows the heat generated after a single large current application to be dispersed along the circumference, preventing it from continuously accumulating in adjacent slots; an insulating terminal block 16 is fixed to the outside of the rear end cover 11, and the terminal block 16 is fixed to the plane of the rear end cover 11 by screws. The output terminals of the main torque coil 13, auxiliary torque coil 14, and temperature rise regulating coil 15 are respectively led to different terminal blocks of the terminal block 16; this grouped lead-out structure forms a physical path through the energized rearrangement method, realizing differentiated excitation for different slot groups;

[0051] The position detection disk 17 is coaxially fixed on the outer side of the rear cover 11. The position detection disk 17 is connected to the rotating shaft 9 by a key. Hall element 18 brackets are arranged on the outer periphery of the position detection disk 17. The Hall element 18 brackets are fixed to the side wall of the rear cover 11 by two screws. A stable gap is maintained between the Hall element 18 and the position detection disk 17. The controller determines the correspondence between the electrical angle of the rotor 8 and the load switching time based on the data collected by the Hall element 18, so that the winding rearrangement switches synchronously according to the temperature rise trend and electrical angle position, preventing torque collapse during switching.

[0052] Example 2:

[0053] Combination Figure 5 As shown, a method for operating a special motor for massage chairs with optimized stator windings includes:

[0054] S1: Establish an initial working framework, record the dwell time and reverse switching number of the rotating shaft 9 at different corner positions within a complete massage action cycle, and mark the slot group associated with the electric corner area whose dwell time is greater than or equal to the preset dwell time threshold as a high heat risk slot group;

[0055] S2: Identify the difference between continuous load and instantaneous impact, compare the repeatability of the dwell time in the same electrical angle region within multiple adjacent action beats, and monitor the opening and closing rhythm of the bimetallic thermal response sheet 12 to determine the load type;

[0056] S3: Perform winding role reordering. After determining that the high-heat-risk slot group has entered a continuous heat accumulation state, transfer the preset proportion of the drive current in the next operation cycle from the main torque coil 13 to the auxiliary torque coil 14, and at the same time increase the participation ratio of the temperature rise distribution coil 15 in the adjacent electric angle interval.

[0057] S4: Perform corner dwell correction, fine-tune the acceleration and deceleration phases within the mechanical action cycle, calculate and output the drift amount of the set rate of change of the relative electrical angle;

[0058] S5: Implement layered current limiting. When the signs of continuous heat accumulation are not relieved, sequentially reduce the continuous conduction ratio of the coil corresponding to the current high-heat-risk slot group, compress the peak energization time of the second drive slot group 5, and reduce the overall target torque.

[0059] S6: Perform self-recovery judgment. When the dwell time of the high-heat risk tank group decreases and the bimetallic thermal response sheet 12 returns to its initial position, after maintaining the participation ratio of the auxiliary torque coil 14 and the temperature rise adjustment coil 15 for a preset time period, the continuous energization range of the main torque coil 13 is gradually restored.

[0060] In the initial stage after the motor is powered on, the controller drives the rotating shaft 9 to rotate according to the standard drive sequence. During the complete operation cycle, the controller records the dwell time of the rotating shaft 9 at different angular positions, the number of reverse switching, and the energization status of the slot group corresponding to the main torque coil 13. If the dwell time corresponding to a certain electrical angle area continuously exceeds the preset threshold, the controller marks the slot group associated with that area as a high-heat-risk slot group.

[0061] Here, the preset threshold is a time limit parameter used to define the abnormal resistance of rotor 8 in a specific electrical angle region. Its physical meaning is to distinguish between normal mechanical reversal pause and abnormal force jamming. The preset threshold is derived by statistically analyzing the average pause time within the normal massage action cycle and multiplying it by a preset tolerance coefficient.

[0062] In the control process, the preset threshold is used as the trigger condition for marking the high-heat-risk slot group. When the real-time recorded dwell time exceeds the threshold continuously, the controller immediately marks the slot group associated with the corresponding electrical angle region as a high-heat-risk slot group and starts the subsequent load type identification and winding rearrangement process. The controller compares the dwell repeatability of the same electrical angle region in multiple adjacent action cycles, and observes the opening and closing rhythm of the bimetallic thermal response sheet 12.

[0063] If the dwell time increases but the bimetallic thermal response plate 12 recovers quickly during the action interval, it is determined to be a momentary impact load; if the dwell time increases and the bimetallic thermal response plate 12 continues to deflect in subsequent cycles, it is determined to be a continuous heat accumulation load; after the controller determines that a certain drive slot group has entered the continuous heat accumulation state, it will transfer the preset proportion of the drive current in the next action cycle from the main torque coil 13 to the auxiliary torque coil 14, increase the participation ratio of the temperature rise distribution coil 15 in the adjacent electric angle interval, and disperse the Joule thermal pulses that originally recurred along the fixed circumferential position in space;

[0064] If a mechanical action repeatedly stops at a specific turning position, the controller will fine-tune the acceleration and deceleration phases within the action cycle, enter the auxiliary torque coil 14 participation area in advance or exit the main torque coil 13 dominance area in a delayed manner, and calculate and output the set rate of change drift of the relative electrical angle.

[0065] The working framework in this process is not simply an experience record sheet, but an operational model used to establish a correspondence between the dwell time of the rotating shaft 9, the number of reverse switching, the state of the bimetallic thermal response sheet 12, and the thermal risk level of the tank group. Logically, it includes three consecutive links: state acquisition, risk mapping, and action allocation. The state acquisition unit receives the position data of the Hall element 18 and the contact state of the bimetallic thermal response sheet 12. The risk mapping unit identifies high-thermal-risk tank groups based on the dwell repeatability and deflection duration. The action allocation unit then adjusts the energizing sequence and proportion of the main torque coil 13, the auxiliary torque coil 14, and the temperature rise adjustment coil 15 accordingly to characterize the dynamic causal relationship between mechanical force, Joule heat generation, and heat conduction and dissipation of the casing 1.

[0066] To ensure the model can be reproduced in the field, the controller uses three consecutive sets of standard massage motion samples as reference samples during the factory debugging phase. Each set of samples covers three working conditions: low speed, standard, and heavy load. The controller uses Hall element 18 to collect angular position pulses, bimetallic thermal response sheet 12 to collect deflection state changes, and drive current to collect the energization time of each coil to form a synchronization data packet. The synchronization data packet is only used to establish the initial correspondence of the working framework and is not used as an external general data model.

[0067] During the calibration process, the manual verification records during the trial operation were used as a reference. The manual verification criteria included whether the dwell time exceeded the reference range, whether the bimetallic thermal response sheet 12 maintained its deflection within adjacent cycles, and whether repeated heat accumulation occurred in the tank group. After the working framework was established, the controller performed a field calibration once after the whole machine was assembled and completed the no-load self-test. This calibration corrected the zero point of the Hall element 18, the initial contact state of the bimetallic thermal response sheet 12, and the electrical angle mapping deviation of each tank group before entering formal operation.

[0068] The above data transfer and calibration steps limit the model to be applicable only to the special motor structure for massage chairs in this embodiment, and it cannot be established independently of the physical connection relationship between the housing 1, the three groups of stator slots, the heat-conducting clips 10 and the bimetallic thermal response sheet 12;

[0069] To ensure programmability of each step, the controller executes the process in a fixed sequence of sampling-determination-rearrangement-current limiting-recovery. Each cycle output includes at least four control quantities: slot group risk level, current load type, coil energization percentage, and recovery status flag. These control quantities are directly written into the current setpoint table and commutation timing table of the driver, without relying on additional inference modules or external network communication.

[0070] When the signs of continuous heat accumulation are not alleviated after the winding role rearrangement and corner dwell correction are implemented, the controller reduces the continuous conduction ratio of the coil corresponding to the current high heat risk slot group, compresses the peak energization time of the second drive slot group 5, and lowers the target torque.

[0071] When the high-heat-risk tank group's dwell time decreases in subsequent cycles, the bimetallic thermal response plate 12 returns to near its initial position. The controller maintains the participation ratio of the auxiliary torque coil 14 and the temperature rise adjustment coil 15 for a preset time period, gradually restoring the continuous energization range of the main torque coil 13 to prevent the tank group, which has just cooled down, from being subjected to full load again, causing reciprocating oscillations. The data sources, processing order, and output objects between the above steps are all clear, and the controller can directly write state machine programs to complete the operation method.

[0072] In S2, the load state is determined by a load state evaluation function, which is calculated based on the residence time increment and the deflection duration of the bimetallic thermal response sheet 12.

[0073] The controller quantifies the risk of heat buildup at the current load using a load state assessment function; The reference dwell time is calculated by subtracting the reference dwell time from the dwell time of the rotating shaft 9 in a specific electric angle region within the current action beat. Here, the reference dwell time refers to the preset standard motion time of the rotating shaft 9 in the corresponding electric angle region under the standard unobstructed massage beat condition.

[0074] The reference dwell time is pre-calibrated and stored in a read-only register by the controller based on the standard action sample library collected during the factory commissioning phase, or it is obtained by the controller through online average statistics of the average time taken for rotor 8 to pass through the electrical angle region during the no-load self-test phase without mechanical obstruction.

[0075] Set as the maximum allowable single obstruction time for the mechanical structure; As a discrete state variable, the value is 1 when the bimetallic thermal response sheet 12 deflects and closes the micro-motion contact, and 0 when the micro-motion contact opens. Considering that the massage chair motor will generate strong mechanical vibration under low-speed heavy load and periodic impact, this vibration is likely to cause high-frequency mechanical chattering of the micro-motion contact of the bimetallic thermal response sheet 12 at the critical point of closure, thus... It exhibits a disordered alternation of 0 and 1 within a short period of time;

[0076] To avoid vibration damaging the integral term For a true representation of heat accumulation, the controller acquires... The time-series circuit incorporates debouncing logic based on a sliding time window: updates are only performed when the state of the micro-motion contact remains consistent within the preset time window. The value of is determined by this process, which adapts the ideal switching quantity assumption to the physical environment of strong vibration.

[0077] Integral term The duration of continuous deflection of the bimetallic thermal response plate 12 within the observation window reflects the degree of heat accumulation inside the casing 1 and stator core 2. and As a weighting coefficient, the proportion of transient mechanical hindrance and steady-state heat accumulation in the evaluation results is adjusted. The purpose of this evaluation function is to unify the two types of inputs, namely residence time change and continuous deflection of bimetallic thermal response plate 12, into comparable risk quantities, so as to avoid the controller misjudging short-term impact based on only a single residence time.

[0078] Its logical structure consists of transient components, continuous components, and weighted adjustment components: the transient component reflects the dwell increment within the current beat, the continuous component reflects the cumulative effect of thermal response within multiple beats, and the weighted adjustment component is used to adjust the influence of the two on the judgment result according to the rhythm of the massage movement.

[0079] Physically, this evaluation function characterizes the relationship between localized heating caused by mechanical resistance, heat transfer to the housing 1 and rear cover 11, and the hysteresis deflection of the bimetallic thermal response sheet 12 due to temperature rise; the load state evaluation function is:

[0080]

[0081] Controller real-time calculation ,when Less than the first threshold and When pulse-like fluctuations occur, it is determined to be a transient impact load; when When the load continues to rise and exceeds the second threshold, and the integral term shows a monotonically increasing trend, it is determined to be a continuous heat accumulation type load.

[0082] Here, the first threshold is a logical evaluation index used to define the boundary of non-destructive short-term impact. It represents the upper limit of short-term stagnation caused by occasional mechanical jamming of the motor. It is obtained by calibrating the maximum allowable stagnation time of the motor under normal operation and the non-operational state of the bimetallic strip. When the evaluation value is less than the first threshold, this state serves as a trigger condition to indicate that the controller does not enter the derating current limiting process and maintains normal output.

[0083] The second threshold is a critical value that quantifies the accumulated heat and may cause local overheating of the stator. This threshold is set based on the heat resistance grade of the stator insulation material and the heat dissipation coefficient of the casing 1. When the evaluation value exceeds the second threshold, this state serves as a logic trigger signal, causing the controller to immediately initiate the control actions of winding role rearrangement and layered current limiting.

[0084] The evaluation function utilizes the physical hysteresis of the bimetallic thermal response sheet 12 combined with the dwell time of the rotating shaft 9 to filter out misjudgments caused by occasional jamming. To ensure the industrial reproducibility of the judgment process, the controller collects no less than twenty typical action beat samples during the factory aging test phase, including room temperature no-load samples, massage head load samples, and equivalent resistance samples. For each set of samples, the tester performs consistency verification based on the dwell time curve, the contact state of the bimetallic thermal response sheet 12, and the temperature rise record of the entire machine surface to uniformly confirm the boundary between instantaneous impact and continuous heat accumulation.

[0085] During field deployment, the controller performs a threshold calibration once after installation. The first and second thresholds are corrected according to the motor assembly deviation, wiring harness impedance and ambient temperature. The correction results are only applicable to this motor and do not deviate from the structural relationship between the housing 1, the heat-conducting clip 10 and the rear cover 11.

[0086] The above-mentioned additional content is used to clarify the input source, labeling basis and calibration steps of the evaluation function, so that it is not a general discrimination model that is detached from the physical object; it should be added that, as a mechanical thermistor, the bimetallic thermal response sheet 12 has inherent discreteness and hysteresis in its response curve, and cannot output high-precision continuous temperature readings.

[0087] Therefore, the integral term in the formula In the underlying software implementation of the controller, instead of high-precision continuous-time integration, it is decomposed into a discrete counter with saturation limit; the controller reads the micro-motion contact state once every fixed sampling period, and the counter only performs step accumulation when the motor is in the energized driving state and the contact is closed.

[0088] This structured decomposition of business logic transforms complex integral operations into simple logical condition accumulation, which avoids the software's over-interpretation of low-precision hardware signals and effectively filters out ambient temperature interference in non-powered states. This ensures that the algorithm's complexity matches the hardware sensor's acquisition capabilities and eliminates the disconnect between the sensor and the algorithm.

[0089] In S3, the winding rearrangement is controlled by a dynamic energization ratio allocation algorithm. This algorithm adjusts the current setpoint of the auxiliary torque coil 14 in real time based on the heat accumulation coefficient of the high-heat-risk slot group. The algorithm extracts the heat accumulation state deviation between the estimated temperature rise and the target safe temperature rise of the current high-heat-risk slot group, and adjusts the distribution current of the auxiliary torque coil based on the deviation.

[0090] After determining that the high-heat-risk tank group has entered a state of continuous heat accumulation, the controller starts the dynamic power-on ratio allocation algorithm to reconstruct the excitation current of each tank group. Defined as the deviation between the current estimated temperature rise and the target safe temperature rise of the high-heat-risk bath group;

[0091] Here, the current estimated temperature rise of the high-heat-risk slot group refers to the increase in the real-time temperature of the winding in the current slot group relative to the ambient reference temperature. This estimated temperature rise is obtained by the controller based on the instantaneous Joule heat generated by the square integral of the phase current of the coil corresponding to the high-heat-risk slot group, combined with the thermal resistance-thermal capacity equivalent first-order lumped parameter thermal network differential model preset in the housing 1, through online discrete recursive calculation.

[0092] Here, the target safe temperature rise is the maximum temperature rise limit that can be allowed for the stator winding to not deteriorate during long-term operation. Its physical meaning is to define the safe control boundary for local heat accumulation. The target safe temperature rise is derived by subtracting the ambient temperature from the maximum allowable temperature corresponding to the stator winding insulation class, and reserving a set temperature margin.

[0093] In the control process, this target safe temperature rise serves as the baseline reference input for the dynamic energization ratio allocation algorithm. When the estimated temperature rise approaches or exceeds this target safe temperature rise, the resulting thermal deviation is... This will serve as the algorithm input to drive subsequent proportional, integral, and differential operations, thereby triggering an increase in the current distribution of the auxiliary torque coil 14 and executing the next thermal load transfer control action.

[0094] Proportional Term Based on the current thermal deviation, the basic auxiliary current command is directly output for rapid response to the thermal accumulation status; integral term Eliminate steady-state thermal deviation to ensure that the thermal accumulation coefficient approaches zero during long-term operation; differential term It predicts the changing trend of heat accumulation and plays a proactive regulatory role when heat levels rise sharply; among which... This is the proportionality coefficient. The integral coefficient is... The differential coefficient is ; the distribution current of the auxiliary torque coil is The specific formula is as follows:

[0095]

[0096] The controller is based on the calculations The given current of the main torque coil 13 in the corresponding electric angle interval is reduced, and this preset proportion of driving current is equivalently transferred to the auxiliary torque coil 14; the controller synchronously increases the duty cycle of the temperature rise distribution coil 15 in the adjacent electric angle interval, and uses the first heat sink group 6 and the second heat sink group 7 to achieve magnetomotive force transition, maintaining the output torque of the rotating shaft 9 smoothly; this algorithm changes the heat carrier and reduces the probability of local heat concentration.

[0097] To ensure the power distribution ratio is practical for field implementation, the controller is tested with three load curves before leaving the factory. , , The calibration process involves three load curves corresponding to light massage, standard massage, and continuous strong stimulation massage, respectively. During the calibration process, the current readback values ​​of each coil, the temperature rise of the outer wall of the housing 1, and the deflection recovery time of the bimetallic thermal response sheet 12 are collected as calibration criteria.

[0098] The manual confirmation standard is as follows: under the same action cycle, the temperature rise increment of the high-heat risk slot group should decrease after the auxiliary torque coil 14 is lifted, and the torque fluctuation should not exceed the preset whole machine comfort threshold. After the adjustment process is completed, the controller will solidify the adjustment parameters into the parameter table corresponding to the current motor position detection disk 17 to ensure that the power-on rearrangement under different assembly positions and different heat dissipation conditions of the casing 1 can be reproduced.

[0099] S4 includes an offset control strategy based on the mapping relationship between mechanical attitude and stator electrical angle. This offset control strategy is based on the reference angular velocity and the set drift time period, combined with the fine-tuning angular acceleration of the acceleration and deceleration phases, and compensates for the preset safety buffer angle to calculate the output target offset angle.

[0100] If the mechanical motion repeatedly stops at a specific turning position, the controller activates an offset control strategy based on the mapping relationship between the mechanical attitude and the stator electric angle; The running speed is determined based on the current set action rhythm; The transition adjustment time window set for the controller is used to control the smoothness of the offset process; The controller adds a preset acceleration increment to the original drive acceleration, which causes the motor to accelerate in advance before entering the dwell area or to slow down when leaving the dwell area. Used to compensate for positioning errors caused by cogging torque fluctuations;

[0101] The above is based on constant acceleration The ideal kinematic offset model, under the nonlinear alternating resistance of the human back faced by the massage chair motor, its acceleration is easily disrupted by the impact of periodic load torque, causing the offset to deviate from the calculated value.

[0102] To ensure the ideal formula holds true under complex operating conditions, the controller strictly limits the execution window of the offset control strategy to triggering within the load reversal dead zone or low resistance range of the mechanical action; simultaneously, in During this period, current feedforward compensation based on transient load observation is introduced to counteract external alternating resistance and maintain stability through current compensation. The constantness of the dynamic load shock eliminates the destruction of the boundary of the ideal kinematic formula;

[0103] The controller calculates the target offset angle based on the model. Subsequently, in the following several action cycles, the original target electrical angle command sequence is translated as a whole. The offset control strategy causes the same mechanical force posture to correspond to different stator slots 3 in different action cycles, causing the first drive slot group 4 and the second drive slot group 5 to alternately bear the peak reaction force, thereby realizing the dynamic rotation of the position of the heat source inside the motor.

[0104] Furthermore, considering that the transmission mechanism of a massage chair will inevitably experience mechanical wear and transmission clearance during long-term operation, this inherent mechanical error can easily lead to fine-tuning angular acceleration. The control effect is completely absorbed by the mechanical backlash, causing the high-precision angular offset to fail in the transmission chain; to resolve this conflict between mechanical action and algorithm accuracy, the controller sets a safety buffer angle. At that time, its minimum value is forcibly clamped above the electrical angle corresponding to the maximum mechanical backlash of the current transmission mechanism;

[0105] The maximum mechanical backlash of the current transmission mechanism refers to the amount of idle angular displacement caused by the tooth flank clearance during the reverse reversal of the massage chair's mechanical transmission gear system. This mechanical backlash is converted into a nominal electrical angle value by multiplying the dead zone mechanical angular displacement measured before leaving the factory by applying a reverse rated torque to the output shaft, multiplying it by the number of pole pairs of the motor, and storing it in the non-volatile memory area of ​​the controller. The reference value for the lower limit of clamping;

[0106] This means that the offset strategy essentially abandons the high-precision fine-tuning of the mechanical end attitude, and instead uses a sufficiently large overall electrical angle offset to ensure that the force stationary point of rotor 8 can effectively cross the mechanical gap and control its transfer to the next stator slot 3. This design allows the algorithm to stably achieve the rotation of heat source positions in a low signal-to-noise ratio mechanical transmission environment without relying on high-precision mechanical response.

[0107] S5 also updates the target torque control parameters through a multi-level derating algorithm, extracts the estimated heat loss and output target torque within a fixed control cycle, and constructs an objective function by combining the torque holding penalty coefficient to output the target torque control parameters.

[0108] When winding rearrangement and corner dwell correction cannot completely suppress heat accumulation, the adaptive current limiting optimization module intervenes. It is calculated by multiplying the stator winding resistance model with the square of the real-time current of each coil, reflecting the heating rate inside the motor; This is the torque command that the motor outputs outward; The value is set between 0 and 1 to attenuate the influence weight of the long-term control cycle, so that the optimization process pays more attention to the recent thermal state.

[0109] To balance cooling and power output requirements, the controller reduces [power output] when heat accumulation is severe. The value of λ forces the optimization algorithm to prioritize reducing heat loss; when heat accumulation is relatively light, the value of λ is increased to maintain output torque; to ensure the dimensionality of the objective function, the penalty coefficient λ has the dimension of angular velocity, thereby... Transformed into estimating heat loss Same power dimensions; here, steady-state expected objective function The calculation formula is:

[0110]

[0111] During the operation of a massage chair, transient mechanical shocks can cause unpredictable and drastic changes in the required torque. If the steady-state objective function is directly solved under such strong dynamic disturbances... It is extremely prone to heat loss. The sudden surge in volume leads to over-compression in the optimization algorithm. This leads to severe torque collapse; to eliminate the violation of the steady-state assumptions of the optimization algorithm by sudden changes in operating conditions, the objective function is immediately frozen when the controller detects that the rate of change of the rotor's 8-angle acceleration exceeds the safety threshold. The update will The current output torque is temporarily set to the preset upper limit of the penalty coefficient to maintain the current output torque until the impact subsides, at which point the derating algorithm is reactivated.

[0112] During the stable, non-impact operating phase, the controller minimizes the objective function. The optimal target torque control parameter sequence is obtained. During execution, the controller sequentially reduces the continuous conduction duty cycle of the high-heat-risk slot group corresponding to the main torque coil 13, compresses the peak energization time of the auxiliary torque coil 14, and lowers the overall output torque target value. This multi-stage derating algorithm selectively intervenes and performs point-to-point current limiting according to the location of the heat source.

[0113] It should be specifically pointed out here that although the objective function is optimized The mathematical expression incorporates mathematical expectation. and discount factor The high-dimensional and complex forms of massage chair motors do not have the computing power to perform stochastic process calculations or complex nonlinear programming in ordinary microcontrollers.

[0114] To ensure the algorithm's complexity matches the microcontroller's computing power, the objective function is structurally decomposed during the software compilation phase as follows: Expected computation Equivalently replaced by based on the past Average data from a sliding window over a fixed control cycle; heat loss Real-time calculations were replaced by a one-dimensional static lookup table indexed by current commands; discount factor This is achieved through a preset shift register decay logic;

[0115] Through the dimensionality reduction process described above, the seemingly complex multi-level derating algorithm is transformed into a simple 'table lookup-shift-accumulation' operation, which can be completed using only basic control logic and arithmetic units. This structured processing reduces the computational complexity of the algorithm and ensures that the optimized algorithm can run stably and in real time on the basic microcontroller hardware.

[0116] S6 also includes a state monitoring and smooth transition mechanism. When thermal recovery is detected, the system automatically switches to the slow-release recovery mode and responds according to the following decision tree: if the derating is caused by a short-term impact, the continuous drive configuration of the main torque coil 13 is immediately restored; if the derating is caused by continuous heat accumulation and the bimetallic thermal response sheet 12 returns to its initial state, the transition state operation is maintained; if the transition state operation time exceeds the set safe time threshold and there is no sign of heat accumulation again, the current limiting of the main torque coil 13 is restored according to the linearly increasing slope; if the bimetallic thermal response sheet 12 is deflected again during the recovery process, the recovery is immediately stopped and the system returns to the previous level current limiting state.

[0117] The controller continuously monitors the dwell time fed back by the Hall element 18 and the contact status of the bimetallic thermal response sheet 12; the reference range refers to the fluctuation range where the dwell time is less than or equal to 1.1 times the reference dwell time; the safe time threshold refers to the shortest cooling duration during which the system can maintain the driving state shared by the main torque coil 13 and the auxiliary torque coil 14. This time threshold is preset to be 1.2 to 1.5 times the physical relaxation time required for the bimetallic thermal response sheet 12 to completely dissipate its body temperature to room temperature from the time the contacts are disconnected.

[0118] When the dwell time of the high-heat-risk tank group decreases to the reference range and the micro-motion contact of the bimetallic thermal response plate 12 is disconnected, the controller activates the smooth transition mechanism. The controller classifies and processes the current limiting based on the historical records of derating triggers. For current limiting caused by short-term impact mis-triggers or extremely short-term delays, the controller directly returns the drive responsibility to the main torque coil 13 and restores the standard drive sequence. For current limiting caused by continuous heat accumulation, the controller maintains the transition state in which the main torque coil 13, auxiliary torque coil 14, and temperature rise adjustment coil 15 share the current when the bimetallic thermal response plate 12 is disconnected, keeping the current current distribution ratio unchanged.

[0119] When the transition state continues for a longer than the set safe time threshold and the load state evaluation function value remains low, the controller gradually increases the upper limit of the current limit of the main torque coil 13 with a fixed current step size according to the preset linear increment slope, and simultaneously decreases the distribution current of the auxiliary torque coil 14. If the bimetallic thermal response sheet 12 deflects and closes again during the current limit increase process, the controller immediately stops the increment process and rolls all control parameters back to the previous current limit state to prevent hot spots from oscillating repeatedly.

[0120] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A special motor for massage chairs with optimized stator windings, characterized in that, include: A housing (1) is provided with a stator core (2) pressed into the housing (1), and a stator slot (3) is provided on the inner side of the stator core (2). The stator slots (3) are divided into a first drive slot group (4), a second drive slot group (5), a first heat exchanger group (6), and a second heat exchanger group (7) in a staggered arrangement along the circumferential direction. The housing (1) is provided with a rotor (8), which is fixed to the shaft (9). The outer wall of the housing (1) is axially pressed with a heat-conducting clip (10), and the rear end of the housing (1) is fixed with a rear end cover (11). A bimetallic thermal response sheet (12) is fixed to the outside of the rear end cover (11), and the bimetallic thermal response sheet (12) is in contact with the rear end face of the thermally conductive clip (10).

2. The special motor for massage chairs with optimized stator windings according to claim 1, characterized in that: The first drive slot group (4) is provided with a main torque coil (13), the second drive slot group (5) is provided with an auxiliary torque coil (14), and the first heat exchanger group (6) and the second heat exchanger group (7) are provided with a temperature rise regulating coil (15). A terminal block (16) is fixed on the outside of the rear end cover (11), and the output terminals of the main torque coil (13), the auxiliary torque coil (14) and the temperature rise regulating coil (15) are respectively led to different terminal blocks of the terminal block (16). A position detection disk (17) is coaxially fixed on the outside of the rear end cover (11), and a Hall element (18) is arranged on the outer periphery of the position detection disk (17).

3. A method for operating a special motor for massage chairs with optimized stator windings, applied to the special motor for massage chairs with optimized stator windings as described in claim 2, characterized in that... include: S1: Establish an initial working framework, record the dwell time and reverse switching number of the rotating shaft (9) at different corner positions within a complete massage action cycle, and mark the slot group associated with the electric corner area whose dwell time is greater than or equal to the preset dwell time threshold as a high heat risk slot group; S2: Identify the difference between continuous load and instantaneous impact, compare the repeatability of the dwell time in the same electric angle region within multiple adjacent action beats, and monitor the opening and closing rhythm of the bimetallic thermal response sheet (12) to determine the load type; S3: Perform winding role rearrangement. After determining that the high-heat-risk slot group has entered a continuous heat accumulation state, transfer the preset proportion of the driving current in the next operation cycle from the main torque coil (13) to the auxiliary torque coil (14), and at the same time increase the participation ratio of the temperature rise regulating coil (15) in the adjacent electric angle interval. S4: Perform corner dwell correction, fine-tune the acceleration and deceleration phases within the mechanical action cycle, calculate and output the drift amount of the set rate of change of the relative electrical angle; S5: Implement layered current limiting. When the signs of continuous heat accumulation are not relieved, sequentially reduce the continuous conduction ratio of the coil corresponding to the current high heat risk slot group, compress the peak energization time of the second drive slot group (5), and reduce the overall target torque. S6: Perform self-recovery judgment. When the dwell time of the high-heat risk tank group drops and the bimetallic thermal response sheet (12) returns to its initial position, after maintaining the participation ratio of the auxiliary torque coil (14) and the temperature rise adjustment coil (15) for a preset time period, the continuous energization range of the main torque coil (13) is gradually restored.

4. The method for operating a special motor for massage chairs with optimized stator windings according to claim 3, characterized in that: In S2, the load type is determined by a load state evaluation function, which is calculated based on the dwell time increment and the deflection duration of the bimetallic thermal response sheet (12).

5. The method for operating a special motor for massage chairs with optimized stator windings according to claim 3, characterized in that: In S3, the winding rearrangement is controlled by a dynamic energization ratio allocation algorithm. The algorithm adjusts the current setpoint of the auxiliary torque coil (14) in real time based on the heat accumulation coefficient of the high heat risk slot group. The algorithm extracts the heat accumulation state deviation between the estimated temperature rise and the target safe temperature rise of the current high heat risk slot group, and adjusts the allocation current of the auxiliary torque coil based on the deviation.

6. The method for operating a special motor for massage chairs with optimized stator windings according to claim 3, characterized in that: The S4 includes an offset control strategy based on the mapping relationship between mechanical attitude and stator electrical angle. This offset control strategy is based on the reference angular velocity and the set drift time period, combined with the fine-tuning angular acceleration of the acceleration and deceleration phases, and compensates for the preset safety buffer angle to calculate and output the target offset angle.

7. The method for operating a special motor for massage chairs with optimized stator windings according to claim 3, characterized in that: In S5, the target torque control parameters are updated through a multi-level derating algorithm, the estimated heat loss and output target torque within a fixed control cycle are extracted, and the objective function is constructed by combining the torque holding penalty coefficient to output the target torque control parameters.

8. The method for operating a special motor for massage chairs with optimized stator windings according to claim 3, characterized in that: The S6 also includes a state monitoring and smooth transition mechanism. When thermal recovery is detected, the system automatically switches to the slow-release recovery mode and responds according to the following decision tree: if the derating is caused by a short-term impact, the continuous drive configuration of the main torque coil (13) is immediately restored. If the derating is caused by continuous heat accumulation and the bimetallic thermal response sheet (12) returns to its initial state, then the transition state operation is maintained; if the transition state operation time exceeds the set safe time threshold and there is no sign of heat accumulation again, then the current limit of the main torque coil (13) is restored according to the linearly increasing slope. If the bimetallic thermal response sheet (12) is deflected again during the recovery process, the recovery will be stopped immediately and the system will return to the previous current-limiting state.

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