Mechanical overload protection mechanism, system and method for motor

Abstract

The invention relates to the field of transmission structures, in particular to a mechanical overload protection mechanism, system and method for a motor. The overload protection mechanism comprises a first sliding bearing, a protection assembly, a second sliding bearing, an elastic piece and a spring seat. An inner cavity is formed in the spring seat, the output end of the motor assembly extends into the inner cavity, the output end of the motor assembly is sleeved with a protection assembly, an elastic piece is arranged between the protection assembly and the spring seat, the first sliding bearing is arranged between the protection assembly and the motor assembly, and the second sliding bearing is arranged between the spring seat and the ball screw pair. The overload state of the output end of the motor can be responded, rigid connection is converted into semi-flexible connection, the problem of motor burnout caused by locked-rotor is effectively avoided, the output torque is directly limited through mechanical action, the fault rate of the motor in the gear shifting execution process is reduced, meanwhile, the gear shifting time and the power interruption time are shortened, and the economical efficiency of the whole vehicle is improved. And meshing tooth abrasion and gearbox fault risks are reduced.

Description

Technical Field

[0001] The present invention relates to the field of transmission structures, and in particular to a motor mechanical overload protection mechanism, system and method. Background Art

[0002] Small-power motors have been widely used in medical equipment, machine tools and engineering machinery industries at home and abroad. In recent years, with the rapid development of new energy, smart cars, robots and automation industries, the application scenarios of small-power motors have become broader.

[0003] Taking the automotive industry as an example, most main drive motors are equipped with complete cooling systems such as oil cooling, water cooling, and air cooling to ensure their good working condition. However, small-power motors such as shift actuators, electronic oil pumps, and electric power take-offs have no reliable cooling systems due to installation space and cost limitations. In addition, the internal circuits of the motors are relatively fragile, and the burning failure rate is high.

[0004] For example, the shift motor in a shift actuator has a speed difference between the sleeve and the meshing gear during gear shifting. There's a chance that the gear won't shift due to a tooth tip failure. This can cause the motor to stall and generate excessive current, quickly burning out. Furthermore, if the timing of shifting is inappropriate and the main drive motor hasn't fully cleared torque, the reverse taper teeth can prevent the sleeve from shifting out of gear. This can cause the motor to stall and generate excessive current, quickly burning out.

[0005] To address the above issues, the existing solution is to add protection logic to the gear shift control program. When the slide cannot engage a gear, the motor reverses and tries to engage the gear again. When the slide cannot disengage the gear, the power supply is suspended, and the gear is disengaged again after a period of time. The core of this logic is to reduce the motor stalling time, but the stalling phenomenon still exists. Because the timing cannot be accurately judged, there is still a certain probability of not being able to engage or disengage the gear when trying again. Multiple attempts will cause the motor to burn out due to multiple stalls. In addition, because the VCU (Vehicle Control Unit), TCU (Transmission Control Unit), motor and other links all have delays and the response time is long, the overall reliability of the protection logic is low. In addition, this protection logic inevitably prolongs the gear shifting time, deteriorates the gear shifting performance, increases power loss during the gear shifting phase, and shortens the cruising range of pure electric vehicles. Summary of the Invention

[0006] In response to the problems mentioned in the prior art, the present invention proposes a motor mechanical overload protection mechanism, system and method. Compared with the commonly used protection logic, the present invention can effectively prevent the shift motor from stalling and reduce the motor failure rate. At the same time, it has a significant positive effect on shortening the shift time and power interruption time, improving the economy of the entire vehicle, reducing meshing tooth wear, and reducing the gearbox failure rate.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a motor mechanical overload protection mechanism, comprising a motor assembly and a ball screw pair connected to each other, an overload protection mechanism disposed between the motor assembly and the ball screw pair, the overload protection mechanism comprising a first sliding bearing, a protection assembly, a second sliding bearing, an elastic member, and a spring seat; An inner cavity is defined in the spring seat, the output end of the motor assembly extends into the inner cavity, and a protective component is sleeved on the output end of the motor assembly. An elastic member is provided between the protective component and the spring seat, the first sliding bearing is provided between the protective component and the motor assembly, and the second sliding bearing is provided between the spring seat and the ball screw pair.

[0008] As a further improvement of the present invention, the protection assembly includes a driving saw gear and a driven saw gear that are meshed and connected, wherein keyways are provided in the middle of the driving saw gear and the driven saw gear.

[0009] As a further improvement of the present invention, when the saw tooth angle of the driving saw gear and the driven saw gear is A and the average working diameter is D, the following relationship is satisfied: T1 / (D / 2)*TAN(A / 2)=F1 Where: T1 is the torque input from the motor assembly to the active saw gear; F1 is the axial force generated by the active saw gear on the driven saw gear.

[0010] As a further improvement of the present invention, the protection assembly includes a driving plane wheel and a driven plane wheel, the driving plane wheel and the driven plane wheel are in contact with each other, wherein the end surface where the driving plane wheel or the driven plane wheel is in contact is coated with a friction layer; The middle parts of the driving plane wheel and the driven plane wheel are provided with key grooves.

[0011] As a further improvement of the present invention, when the friction coefficient of the friction surface of the driving flat wheel and the driven flat wheel is X and the average working diameter is D, the following relationship is satisfied: T1=F1*D / 2 F1(MAX)=F0*X T2(MAX)=F0*X*D / 2 Where: T1 is the torque input from the motor assembly to the driving plane wheel; T2 is the output torque from the driven plane wheel to the ball screw pair; F0 is the axial force of the elastic member on the driven saw gear; F1 is the friction force generated by the driving plane wheel on the driven plane wheel.

[0012] As a further improvement of the present invention, the protection assembly includes a driving conical wheel and a driven conical wheel, the driving conical wheel and the driven conical wheel are in contact with each other, wherein the end surface where the driving conical wheel or the driven conical wheel is in contact is coated with a friction layer; The middle parts of the driving conical wheel and the driven conical wheel are provided with keyways.

[0013] As a further improvement of the present invention, when the friction cone coefficient of the driving conical wheel and the driven conical wheel is X, the cone angle is A, and the average working diameter is D, the following relationship is satisfied: T1=F1*D / 2 F1(MAX)=F0 / SIN(A)*X T2(MAX)=F0 / SIN(A)*X*D / 2 Where: T1 is the torque input from the motor assembly to the driving conical wheel; T2 is the output torque from the driven conical wheel to the ball screw pair; F0 is the axial force of the elastic member on the driven conical wheel; F1 is the friction force generated by the driving conical wheel on the driven conical wheel.

[0014] As a further improvement of the present invention, the spring seat includes a base, a cylinder containing an inner cavity extends from the center of the base, a through hole for the output end of the motor assembly to pass through is opened axially on the cylinder, and a plurality of oil holes are opened on the circumferential surface of the cylinder.

[0015] In a second aspect, the present invention provides a motor control system including the motor mechanical overload protection mechanism as described above.

[0016] In a third aspect, the present invention provides a method for controlling a motor control system, using the above-mentioned motor control system, comprising the following steps: When tooth top occurs, the motor's mechanical protection structure can change the motor assembly and the ball screw pair from a rigid connection to a semi-flexible connection, so that the motor can continue to output torque to the ball screw pair without stalling. When the sleeve and the meshing gear change from a tooth top tooth to a semi-meshing state, the shift fork immediately shifts into gear. After the gear shift reaches the limit position and before the TCU issues a stop enable command, the motor and the ball screw pair are semi-flexibly connected, and the motor continues to rotate until the TCU recognizes the gear shift in place signal and issues a stop command.

[0017] Compared with the prior art, the present invention has achieved the following technical effects: The mechanical overload protection structure of the present invention, consisting of a sliding bearing, protective assembly, elastic member, and spring seat, responds in real time to overload conditions at the motor output, converting the rigid connection into a semi-flexible connection, effectively preventing motor burnout due to stalling. This mechanism directly limits output torque through mechanical action, significantly reducing the motor's failure rate during shifting, while also shortening shift times and power interruption durations. This improves vehicle economics and reduces the risk of gear wear and transmission failure.

[0018] The protection component of the present invention adopts three different structural gear meshing structures. The three different structures can adapt to different usage scenarios and working conditions. The meshing structure of the active saw gear and the driven saw gear is adopted, combined with the optimized relationship between the saw tooth angle and the average working diameter, to control the torque transmission threshold; for the protection component using the active plane wheel and the driven plane wheel or the active conical wheel and the driven conical wheel, the sensitivity and stability of the torque limit are further optimized through the friction layer design and the matching of the friction coefficient and the cone angle.

[0019] Compared with the use process of the existing gear shift actuator, the motor control system of the present invention is different from the gear shift logic of the existing structure that requires repeated attempts. The system of the present invention does not need to be powered off or returned during the gear shifting and disengaging stages, and always acts quickly at the best time. While realizing the motor protection function, it can shorten the gear shifting time, reduce power loss, and improve product quality.

[0020] The mechanical overload protection structure of the present invention is also applicable to electric power take-offs and electronic oil pumps in the automotive industry, as well as other scenarios using low-power motors such as the robotics, automation, and medical equipment industries, and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of Example 1 of the present invention; Figure 2 This is a schematic diagram of a protection component according to embodiment 1 of the present invention; Figure 3 This is a force analysis diagram of the protection component of Example 1 of the present invention; Figure 4 This is a schematic structural diagram of Example 2 of the present invention; Figure 5 This is a schematic diagram of a protection component according to embodiment 2 of the present invention; Figure 6 This is a force analysis diagram of the protection component of Example 2 of the present invention; Figure 7 This is a schematic structural diagram of Example 3 of the present invention; Figure 8 This is a schematic diagram of a protection component according to embodiment 3 of the present invention; Figure 9 This is a force analysis diagram of the protection assembly of Example 3 of the present invention; Figure 10 This is a schematic diagram of the spring seat structure of the present invention; Figure 11 This is the existing protection logic flow chart; Figure 12 It is a logical schematic diagram of the present invention.

[0022] Figure numerals: 1. Motor assembly; 2. First sliding bearing; 3. Active saw gear; 4. Driven saw gear; 5. Elastic member; 6. Spring seat; 7. Second sliding bearing; 8. Displacement sensor; 9. Magnet assembly; 10. Ball screw pair; 11. Bearing; 12. Dial head; 13. Pivot; 14. Housing; 15. Active flat wheel; 16. Driven flat wheel; 17. Active conical wheel; 18. Driven conical wheel. DETAILED DESCRIPTION

[0023] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0026] In the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0027] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0028] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0029] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0030] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0032] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0033] Example 1 like Figure 1As shown, the present invention provides a mechanical overload protection mechanism for a motor, comprising a connected motor assembly 1 and a ball screw pair 10, wherein an overload protection mechanism is provided between the motor assembly 1 and the ball screw pair 10, and the overload protection mechanism comprises a first sliding bearing 2, a protection component, a second sliding bearing 7, an elastic member 5 and a spring seat 6; an inner cavity is defined in the spring seat 6, the output end of the motor assembly 1 extends into the inner cavity, and a protection component is sleeved on the output end of the motor assembly 1, an elastic member 5 is provided between the protection component and the spring seat 6, the first sliding bearing 2 is provided between the protection component and the motor assembly 1, and the second sliding bearing 7 is provided between the spring seat 6 and the ball screw pair 10.

[0034] like Figure 1 As shown, the motor mechanical overload protection mechanism of the present invention is specifically installed between the motor assembly 1 and the ball screw pair 10. Figure 1 The other structural arrangements of the electronically controlled electric actuator are basically the same as those of the existing device. The displacement sensor 8 is connected to the ball screw pair 10 through the magnet assembly 9. The ball screw pair 10 is connected to a bearing 11 at one end away from the motor assembly 1. The ball screw pair 10 drives the shift head 12 installed on the pivot 13 to move. The entire structure of the electronically controlled electric actuator is installed in the housing 14.

[0035] like Figure 1 As shown, the protection component of this embodiment includes an active saw gear 3 and a driven saw gear 4 that are meshed and connected, wherein the end faces of the active saw gear 3 and the driven saw gear 4 are provided with a sawtooth structure, the sawtooth structure has a good safety factor consistency, and the processing cost is relatively high, and the power is controlled by the active saw gear 3 and the driven saw gear 4. The middle part of the active saw gear 3 and the driven saw gear 4 is provided with a hexagonal groove or a spline groove, which respectively cooperates with the hexagonal key or spline on the motor assembly 1 and the ball screw pair 10 to transmit power; the first sliding bearing 2 and the second sliding bearing 7 provided in the embodiment are specifically end face sliding The bearing is used to limit the axial position and reduce the rotational resistance; the elastic member 5 is installed between the driven saw gear 4 and the spring seat 6, and the axial dimension chain is used to generate appropriate axial preload force when it is installed, so that the teeth of the active saw gear 3 and the driven saw gear 4 are kept in meshing state. In the embodiment, the elastic member 5 is preferably a disc spring, which can generate sufficient preload force within a smaller axial dimension, but the preload force tolerance is large, and an adjustment pad can be added for compensation; if the installation space permits or the motor torque is small, the use of a spiral compression spring can also achieve the requirements of this patent.

[0036] like Figure 10 As shown, the spring seat 6 is installed in the groove of the housing 14. The spring seat 6 includes a base. A cylinder containing an inner cavity extends from the center of the base. A through hole is provided at the bottom of the inner cavity. The output end of the motor assembly 1 is connected to the ball screw pair 10 through the inner cavity and the through hole. A plurality of oil holes are provided on the circumferential surface of the cylinder to ensure good lubrication of the internal parts.

[0037] The principle of the motor mechanical overload protection mechanism in this embodiment is as follows: When there is no jamming at the shifting head 12, the motor assembly 1 is not stalled, and the torque is within the normal range. The saw teeth of the driving saw gear 3 and the driven saw gear 4 are kept engaged under the action of the elastic member 5, and the power is transmitted in sequence.

[0038] When there is jamming at the shifting head 12, the motor assembly 1 outputs a large torque, and the saw teeth of the driving saw gear 3 and the driven saw gear 4 rotate relative to each other against the spring force of the elastic member 5. At this time, the motor assembly 1 is not completely stalled, so it will not burn out in a short time. The driven saw gear 4 is driven by the waveform of the driving saw gear 3. Therefore, there is still enough gear engagement force or gear disengagement force at the shifting head 12. When the sliding sleeve completes tooth alignment or the driving motor completely clears the torque instantaneously, the shifting head 12 can immediately generate corresponding actions, without missing the shifting opportunity. Therefore, the shifting time is shorter and the power loss is less.

[0039] As Figure 2 and Figure 3 shown, when defining the saw tooth angle of the driving saw gear 3 and the driven saw gear 4 as A and the average working diameter as D, neglecting the frictional force calculation, the following relational expression is satisfied: T1 / (D / 2)*TAN(A / 2)=F1 This formula can be transformed into: T1=F1 / TAN(A / 2)*(D / 2) In the formula: T1 is the torque input by the motor assembly to the driving saw gear; F1 is the axial force generated by the driving saw gear on the driven saw gear.

[0040] In the embodiment, T2 is the output torque from the driven saw gear to the ball screw pair, and F0 is the axial force of the elastic member on the driven saw gear; Since the axial deformation amount and axial elastic force of the elastic member increase with the increase of T1, when the axial deformation amount of the elastic member is less than the saw tooth height, the driving saw gear 3 and the driven saw gear 4 are kept engaged, and T2=T1; when the axial deformation amount of the elastic member is greater than the saw tooth height, relative movement will occur between the driving saw gear 3 and the driven saw gear 4, and the torque is not transmitted. At this time, T2 = 0.

[0041] When F1 < F0, the elastic member maintains its original position, and the driving saw gear 3 and the driven saw gear 4 remain engaged, T1 = T2; When there is jamming at the shifting head 12, T1 and F1 increase. When F1 > F0, the elastic member is compressed, and the driving saw gear 3 and the driven saw gear 4 rotate relative to each other. The motor assembly 1 is not stalled and there is no risk of burning out. When each saw tooth rotates, a torque will be generated on the driven saw gear X. Therefore, the waveform of T2 changes, and there is still enough gear engagement force or gear disengagement force at the shifting head 12. When the sliding sleeve completes tooth alignment or the driving motor completely clears the torque instantaneously, the shifting head 12 can immediately generate corresponding actions.

[0042] When the shift head 12 moves, F1 < F0, the elastic member remains in its original position, the driving saw gear and the driven saw gear remain engaged, and T1 = T2.

[0043] Embodiment 2 This embodiment is basically the same as Embodiment 1, except that the protection component of the present invention includes a driving flat wheel 15 and a driven flat wheel 16, the driving flat wheel 15 and the driven flat wheel 16 are in contact with each other, and a friction layer is coated on the end face where the driving flat wheel 15 or the driven flat wheel 16 is in contact. Key grooves are provided in the middle of the driving flat wheel 15 and the driven flat wheel 16.

[0044] As Figure 4 , Figure 5 and Figure 6 shown, the end faces of the driving flat wheel 15 and the driven flat wheel 16 are flat, and the end faces of the driving flat wheel 15 and the driven flat wheel 16 are in contact with each other, with a simple structure and the axial installation dimension can be shortened; in the embodiment, a friction material needs to be added to any one of the end faces of the driving flat wheel 15 or the driven flat wheel 16 through processes such as bonding and spraying to form a friction layer. In this embodiment, it is preferred to form a friction layer on the end face of the driving flat wheel 15. According to different usage scenarios, a friction layer can also be selected on the end face of the driven flat wheel 16; the friction material can be one of carbon fiber, carbon particles, molybdenum layer, etc. The friction material is required to have a stable coefficient and be wear-resistant, and the on-off of power is controlled through the end face friction force.

[0045] Define the friction coefficient of the friction surface of the driving flat wheel 15 and the driven flat wheel 16 as X, and when the average working diameter is D, the following relational formula is satisfied: T1 = F1 * D / 2 F1(MAX) = F0 * X T2(MAX) = F0 * X * D / 2 In the formula: T1 is the torque input from the motor assembly to the driving flat wheel; T2 is the output torque from the driven flat wheel to the ball screw pair; F0 is the axial force of the elastic member on the driven saw gear; F1 is the frictional force generated by the driving flat wheel on the driven flat wheel.

[0046] When there is no jamming at the shift head 12 and T1 is within the normal range, F1 < F1(MAX), the driving flat wheel 15 and the driven flat wheel 16 remain in a static friction state, and T1 = T2; When there is jamming at the shift head 12, T1 and F1 increase. When F1 > F1(MAX), the driving flat wheel 15 and the driven flat wheel 16 change from the static friction state to the dynamic friction state. The motor assembly 1 is not stalled and there is no risk of burning out. The driven flat wheel 16 is driven by the dynamic frictional force, and there is still sufficient gear engagement force or gear disengagement force at the shift head 12. When the sliding sleeve completes gear engagement or the driving motor completely clears the torque instantaneously, the shift head 12 can immediately generate a corresponding action.

[0047] When the ejector 12 moves, F1 < F1(MAX), the driving flat gear 15 and the driven flat gear 16 resume the static friction state, and T1 = T2.

[0048] Embodiment 3 This embodiment is basically the same as Embodiment 1 and Embodiment 2. The difference is that the protection component includes a driving conical gear 17 and a driven conical gear 18, and the driving conical gear 17 and the driven conical gear 18 are in contact with each other. There is a friction layer on the end face where the driving conical gear 17 or the driven conical gear 18 is in contact; there are key grooves in the middle of the driving conical gear 17 and the driven conical gear 18.

[0049] As Figure 7 , Figure 8 and Figure 9 shown, the end faces of the driving conical gear 17 and the driven conical gear 18 in this embodiment are conical surfaces. As Figure 8 or Figure 9 shown, the end face of the driving conical gear 17 is an inner conical surface, and the end face of the driven conical gear 18 is an outer conical surface. The inner conical surface and the outer conical surface are in contact with each other, shortening the radial installation dimension and having better friction stability; in the embodiment, a friction material is added to any one of the end faces of the driving conical gear 17 or the driven conical gear 18 through processes such as bonding and spraying to form a friction layer. In this embodiment, it is preferably to form a friction layer on the end face of the driven conical gear 18. According to different usage scenarios, it is also possible to choose to form a friction layer on the end face of the driven flat gear 16; the friction material can be one of carbon fiber, carbon particles, molybdenum layer, etc. The friction material is required to have a stable coefficient and be wear-resistant, and the power on and off is controlled by the end face friction force.

[0050] Define the friction conical surface coefficient of the driving conical gear and the driven conical gear as X, the conical angle as A, and the average working diameter as D. The following relational formula is satisfied: T1 = F1 * D / 2 F1(MAX) = F0 / SIN(A) * X T2(MAX) = F0 / SIN(A) * X * D / 2 In the formula: T1 is the torque input by the motor assembly to the driving conical gear; T2 is the output torque from the driven conical gear to the ball screw pair; F0 is the axial force of the elastic part on the driven conical gear; F1 is the friction force generated by the driving conical gear on the driven conical gear.

[0051] When there is no jamming at the ejector 12 and T1 is within the normal range, F1 < F1(MAX), the driving conical gear 17 and the driven conical gear 18 maintain the static friction state, and T, = T2; When the shift head 12 is stuck, T1 and F1 increase. When F1 > F1(MAX), the driving conical surface wheel 17 and the driven conical surface wheel 18 change from the static friction state to the dynamic friction state. The motor assembly 1 is not blocked and there is no risk of burning out. The driven conical surface wheel 18 is driven by the dynamic frictional force, and there is still sufficient forward gear force or reverse gear force at the shift head 12. When the sliding sleeve completes tooth engagement or the driving motor completely clears the torque instantaneously, the shift head 12 can immediately generate corresponding actions.

[0052] When the shift head 12 moves, F1 < F1(MAX), and the driving conical surface wheel 17 (restores the static friction state with the driven conical surface wheel 18, and T1 = T2.

[0053] Embodiment 4 This embodiment is basically the same as Embodiment 1, Embodiment 2, and Embodiment 3. The difference is that the present invention proposes a motor control system including the above-mentioned motor mechanical overload protection mechanism.

[0054] As Figure 11 Shown is the protection logic for the motor in the prior art. Specifically, after the TCU receives the shift command from the VCU, it controls the output speed and torque of the shift motor, which finally acts on the shift fork through transmission structures such as ball screws and worm gears. When the shift fork moves, the angular displacement sensor or linear displacement sensor detects its displacement. After reaching the shift-in-place position, it is fed back to the TCU. The TCU controls the shift motor to stop enabling, and feeds back the shift completion signal to the VCU. When the TCU determines shift jamming or motor blockage based on the displacement change of the displacement sensor, it controls the shift motor to stop enabling, reverse, and wait for a short time before attempting to shift again until the shift is successful.

[0055] The main problems of the above control program are as follows: From the shift-in-place, shift jamming, and the motor being in a blocked state to the TCU issuing reverse and power-off commands to the shift motor, there are many intermediate links and the total delay is long. During this stage, the motor current is too large and the temperature rise is too high, resulting in short-term performance degradation of the motor and shortening the service life of the motor. Due to the constant speed difference between the sliding sleeve and the meshing gear during the shift process, the condition of tooth tip contact is inevitable, and there is still a possibility of tooth tip blockage when the motor retreats, waits, and attempts again.

[0056] And multiple retreats, waits, and attempts will lead to problems such as extended shift time, increased number of impacts between meshing teeth, too long power interruption, and poor shift economy. At the same time, multiple blockages in a short period of time cause a significant decline in motor performance, a decrease in shift force, and a reduction in the probability of shifting into gear. In addition, there is a possibility that the TCU fails to recognize the motor blockage in time due to reasons such as compatibility differences between the displacement sensor, shift motor, and controller, and differences in the dimensional consistency of components, resulting in motor burnout. In summary, simply protecting the motor through the control program has low reliability and has an adverse impact on shift performance, vehicle economy, and the service life of the sliding sleeve and meshing gear.

[0057] As Figure 12 As shown, the present invention incorporates the protection logic of the motor control system with a mechanical motor overload protection mechanism. Upon receiving a shift command from the VCU, the TCU controls the shift motor's output speed and torque, which ultimately acts on the shift fork via a transmission mechanism including a ball screw and worm gear. As the fork moves, an angular displacement sensor or linear displacement sensor detects its displacement. Once the shift fork reaches the in-position position, feedback is provided to the TCU. The TCU then deactivates the shift motor and transmits a shift completion signal to the VCU.

[0058] When conditions such as tooth topping occur, the TCU and the shift motor maintain their current state. The motor mechanical protection structure can change the motor assembly and the ball screw pair from a rigid connection to a semi-flexible connection, so that the motor can continue to output torque to the ball screw pair without stalling. When the sleeve and the meshing gear change from a tooth top tooth to a semi-meshing state, the shift fork immediately shifts into gear. After the gear shift reaches the limit position and before the TCU issues a stop enable command, the motor and the ball screw pair are semi-flexibly connected, and the motor continues to rotate until the TCU recognizes the gear shift in place signal and issues a stop command.

[0059] The protection logic of this invention eliminates the need for the TCU to determine whether the motor is stalled, and eliminates the need to control the motor to retract, wait, and retry if a shift fails. This results in a simple control process and high reliability. The shift fork maintains sufficient shift force even when it engages the tooth, enabling gear engagement in the shortest possible time. This shortens shift times and power interruptions, improving the driving experience and overall vehicle economy. The shift motor remains unstalled throughout the entire process, and the sliding sleeve only collides with the meshing gear once, effectively extending the service life of the motor and transmission components.

[0060] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and range of equivalents of the claims are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0061] In addition, it should be understood that although this specification describes the embodiments, not every embodiment contains only one independent technical solution. This description is for clarity only. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for the purpose of illustrating the technical concept of the present invention and cannot be used to limit the scope of protection of the present invention. Any changes made based on the technical solution in accordance with the technical concept proposed by the present invention fall within the scope of protection of the claims of the present invention.

Claims

1. A motor mechanical overload protection mechanism, comprising a motor assembly and a ball screw pair connected to each other, wherein an overload protection mechanism is provided between the motor assembly and the ball screw pair, characterized in that: The overload protection mechanism includes a first sliding bearing, a protection assembly, a second sliding bearing, an elastic member and a spring seat; An inner cavity is defined in the spring seat, the output end of the motor assembly extends into the inner cavity, and a protective component is sleeved on the output end of the motor assembly. An elastic member is provided between the protective component and the spring seat, the first sliding bearing is provided between the protective component and the motor assembly, and the second sliding bearing is provided between the spring seat and the ball screw pair.

2. A motor mechanical overload protection mechanism according to claim 1, characterized in that: The protection component comprises a driving saw gear and a driven saw gear which are meshed and connected, wherein key grooves are provided in the middle of the driving saw gear and the driven saw gear.

3. A motor mechanical overload protection mechanism according to claim 2, characterized in that: When the tooth angle of the active saw gear and the driven saw gear is A and the average working diameter is D, the following relationship is satisfied: T1 / (D / 2)*TAN(A / 2)=F1 Where: T1 is the torque input from the motor assembly to the active saw gear; F1 is the axial force generated by the active saw gear on the driven saw gear.

4. A motor mechanical overload protection mechanism according to claim 1, characterized in that: The protection assembly includes a driving plane wheel and a driven plane wheel, wherein the driving plane wheel and the driven plane wheel are in contact with each other, wherein the end surface where the driving plane wheel or the driven plane wheel is in contact is coated with a friction layer; The middle parts of the driving plane wheel and the driven plane wheel are provided with key grooves.

5. A motor mechanical overload protection mechanism according to claim 4, characterized in that: When the friction coefficient of the friction surface of the driving flat wheel and the driven flat wheel is X and the average working diameter is D, the following relationship is satisfied: T1=F1*D / 2 F1(MAX)=F0*X T2(MAX)=F0*X*D / 2 Where: T1 is the torque input from the motor assembly to the driving plane wheel; T2 is the output torque from the driven plane wheel to the ball screw pair; F0 is the axial force of the elastic member on the driven saw gear; F1 is the friction force generated by the driving plane wheel on the driven plane wheel.

6. A motor mechanical overload protection mechanism according to claim 1, characterized in that: The protection assembly includes a driving conical wheel and a driven conical wheel, wherein the driving conical wheel and the driven conical wheel are in contact with each other, wherein the end surface where the driving conical wheel or the driven conical wheel is in contact is coated with a friction layer; The middle parts of the driving conical wheel and the driven conical wheel are provided with keyways.

7. A motor mechanical overload protection mechanism according to claim 6, characterized in that: When the friction cone coefficient of the driving conical wheel and the driven conical wheel is X, the cone angle is A, and the average working diameter is D, the following relationship is satisfied: T1=F1*D / 2 F1(MAX)=F0 / SIN(A)*X T2(MAX)=F0 / SIN(A)*X*D / 2 Where: T1 is the torque input from the motor assembly to the driving conical wheel; T2 is the output torque from the driven conical wheel to the ball screw pair; F0 is the axial force of the elastic member on the driven conical wheel; F1 is the friction force generated by the driving conical wheel on the driven conical wheel.

8. The motor mechanical overload protection mechanism according to claim 1, characterized in that: The spring seat includes a base, a cylinder containing an inner cavity extends from the center of the base, a through hole for the output end of the motor assembly to pass through is opened axially on the cylinder, and a plurality of oil holes are opened on the circumferential surface of the cylinder.

9. A motor control system, characterized in that: The invention comprises a motor mechanical overload protection mechanism as described in any one of claims 1 to 8.

10. A method for controlling a motor system, characterized in that , using the motor control system as claimed in claim 9, comprising the following steps: When tooth top occurs, the motor's mechanical protection structure can change the motor assembly and the ball screw pair from a rigid connection to a semi-flexible connection, so that the motor can continue to output torque to the ball screw pair without stalling. When the sleeve and the meshing gear change from a tooth top tooth to a semi-meshing state, the shift fork immediately shifts into gear. After the gear shift reaches the limit position and before the TCU issues a stop enable command, the motor and the ball screw pair are semi-flexibly connected, and the motor continues to rotate until the TCU recognizes the gear shift in place signal and issues a stop command.

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