automatic gear shift mechanism

Abstract

This application relates to the field of transmission control technology, and more particularly to an automatic shifting mechanism for vehicles. The automatic shifting mechanism includes a housing assembly (1), a motor (2), a hollow shaft (3), a nut sleeve (41), and a lead screw (42). Since the hollow shaft (3) is fixedly connected to the inner rotor of the motor (2), the hollow shaft (3) rotates synchronously with the inner rotor of the motor (2), and the nut sleeve (41) also rotates along with the hollow shaft (3). Simultaneously, because the end of the lead screw (42) is limited by the housing assembly (1) and cannot rotate, the lead screw (42) moves axially along the thread of the rotating nut sleeve (41), achieving linear motion of extension or retraction. By coaxially integrating the motor (2) and the lead screw (42) mechanism, the structure is very compact, the transmission chain is short, and the efficiency is high, achieving precise electronically controlled linear drive.

Description

Technical Field

[0001] This application relates to the field of transmission control technology, and more particularly to an automatic gear shifting mechanism for vehicles. Background Technology

[0002] An automatic gear shifting mechanism is a core mechatronic actuator. Its main function is to receive commands from the electronic control unit (ECU), convert electrical energy into precise mechanical motion, and drive the shift forks or other components within the gearbox to move, thereby achieving automatic gear shifting. With the rapid development of the automotive industry, especially new energy vehicles and intelligent driving technologies, and their widespread application in industrial automation, the performance requirements for automatic gear shifting mechanisms are becoming increasingly stringent. These mechanisms must not only be fast and precise in shifting, but also compact in structure, reliable in operation, and low in energy consumption.

[0003] Currently, most commercially available electric automatic gear shifting mechanisms operate on the principle of a motor driving a lead screw mechanism. This converts the motor's rotational motion into the lead screw's linear motion, thereby outputting thrust or pull force to complete the gear shifting action. However, in practical implementation, a standard motor and the lead screw mechanism are typically connected in series via couplings or other components. While this approach is relatively simple, the combined length of the motor and the lead screw results in an excessively long axial dimension of the entire actuator, posing a significant challenge to installation space.

[0004] Existing automatic shifting mechanisms generally suffer from problems such as dispersed structure and low integration. The combination of their power source (motor) and actuator (screw and nut mechanism) often results in defects such as excessively large overall size (axial or radial), excessively long transmission chain, transmission backlash affecting accuracy, and numerous parts leading to low reliability. Utility Model Content

[0005] In view of this, the present invention proposes a compact automatic gear shifting mechanism.

[0006] The automatic gear shifting mechanism provided by this utility model includes a housing assembly, a motor, a hollow shaft, a nut sleeve, and a lead screw. The housing assembly includes a main housing with an axially extending cavity inside. The motor has an outer stator and an inner rotor. The outer stator is connected to the inner wall of the main housing, and the inner rotor has an axially hollow portion. The hollow shaft passes through and is connected to the axially hollow portion of the motor, and has a central hole. The nut sleeve is fitted into the central hole. The lead screw passes through the nut sleeve and is threadedly engaged with it. Its output end extends beyond the axial front end of the housing assembly, and its end is limited by the rear end of the housing assembly, allowing the lead screw to extend and retract only axially.

[0007] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the nut sleeve is keyed to the inner wall of the central hole, and a support platform is formed inside the central hole of the hollow shaft, with the bottom end of the nut sleeve pressing against the support platform. The automatic shifting mechanism further includes an end piece and a first bearing. The end piece has an axially connected frustum and a tube portion. The tube portion extends into the central hole to press against the top end of the nut sleeve, and the frustum portion is connected to the top end of the hollow shaft. The end piece has a through hole through which the lead screw passes. The inner ring of the first bearing is pressed between the frustum portion of the end piece and the top surface of the first outer ring step of the outer wall of the hollow shaft.

[0008] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the housing assembly includes a front cover connected to one end of the main housing, and a stepped groove is formed on the side facing the main housing. The stepped groove includes a large-diameter section near the main housing and a small-diameter section adjacent to the large-diameter section. The stepped surface of the large-diameter section presses against the outer ring of the first bearing, and the small-diameter section accommodates the frustum portion of the end piece. Furthermore, a through hole is formed at the top of the front cover for the lead screw to pass through, and an annular groove for installing a sealing ring is provided on the radial inner wall of the through hole. An installation groove for installing a dustproof ring is formed at the outer end of the through hole, and the sealing ring and the radial inner side of the dustproof ring are both sealed and fitted with the lead screw.

[0009] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the middle seat of the housing assembly is connected to the axial bottom end of the main housing, and an inner ring step is formed on its inner wall side. Furthermore, the automatic shifting mechanism also includes a second bearing, wherein the top of the inner ring of the second bearing is arranged such that the top of its inner ring presses against the second outer ring step of the hollow shaft, and the bottom of its outer ring presses against the top surface of the inner ring step.

[0010] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the automatic shifting mechanism further includes an encoder assembly, which includes a magnetic ring and a detection circuit board. The magnetic ring is connected to the third outer ring step of the hollow shaft, and the detection circuit board is connected to the bottom surface of the inner ring step of the middle seat of the housing assembly and faces the magnetic ring.

[0011] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the rear seat of the housing assembly is provided with a guide groove extending parallel to its axial direction; the automatic shifting mechanism also includes a limiting pin, which passes through the rear end of the lead screw and is arranged radially along the lead screw, and the limiting pin cooperates with the guide groove to guide and limit the movement so as to slide only along the guide groove.

[0012] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the bottom end of the rear seat is provided with two opposing limiting pillars, and an arc-shaped limiting sleeve is respectively fitted into the notches on the opposite sides of the two limiting pillars, and the guide groove is formed between the two arc-shaped limiting sleeves; the automatic shifting mechanism also includes a dust cover, which is configured to cover the two limiting pillars and its end is connected to the rear seat.

[0013] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the automatic shifting mechanism further includes a brake, which comprises a brake plate and a drive component. Multiple screws are radially inserted through the brake plate and connected to the hollow shaft. The drive component includes an electromagnet-driven brake pad, disposed in a mounting cavity formed at the rear of the housing assembly, and facing the brake plate.

[0014] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the flange of the housing assembly connects the middle seat and the rear seat, and a ring of alignment teeth is provided on the radially outer side of the flange. The middle seat is provided with a first cable guide hole for the motor cable to pass through, the flange is provided with at least one second cable guide hole for the encoder cable and the motor cable to pass through, and the rear seat is provided with at least two gland heads for fixing the cables.

[0015] In a preferred embodiment of the automatic shifting mechanism provided by this utility model, the automatic shifting mechanism further includes a connecting assembly that cooperates with the gearbox. The connecting assembly includes a bearing support, a third bearing, a pressure ring, and bolts. The bearing support is fitted onto the output end of the lead screw, with a radially outwardly extending annular platform at its bottom and a radially inwardly extending limiting end at its top. The limiting end abuts against the front end of the lead screw. The bottom of the inner ring of the third bearing presses against the limiting end for connecting to an external gearbox. The pressure ring presses against the top of the inner ring of the third bearing. Bolts are connected to the front end of the lead screw and fix the pressure ring.

[0016] This application integrates the motor rotor, the hollow shaft for transmission, the nut sleeve, and the linear motion lead screw concentrically in the axial direction into the housing assembly, which greatly shortens the transmission chain and eliminates intermediate transmission components such as couplings and synchronous belts. This solves the technical problems of bulky structure, low integration, and low transmission accuracy in the prior art, and provides an automatic shifting mechanism with a more compact structure, more direct transmission, and more precise positioning. Attached Figure Description

[0017] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can more clearly understand the above and other features and advantages of the present invention, in which:

[0018] Figure 1 This is a schematic diagram of the external structure of the automatic gear shifting mechanism in this embodiment.

[0019] Figure 2 This is a cross-sectional view of the automatic gear shifting mechanism in this embodiment.

[0020] Figure 3 This is a schematic diagram of the lead screw connection structure in the automatic shifting mechanism of this embodiment.

[0021] Figure 4 This is a schematic diagram of the connection structure of the first bearing in the automatic shifting mechanism of this embodiment.

[0022] Figure 5 This is a schematic diagram of the front cover structure in the automatic shifting mechanism of this embodiment.

[0023] Figure 6 This is a schematic diagram of the internal structure of the automatic gear shifting mechanism in this embodiment.

[0024] Figure 7 This is a schematic diagram of the connection structure of the middle seat of the automatic shifting mechanism in this embodiment.

[0025] Figure 8 This is a schematic diagram of the anti-rotation structure of the lead screw in the automatic shifting mechanism of this embodiment.

[0026] Figure 9 This is a schematic diagram of the installation structure of the brake of the automatic gear shifting mechanism in this embodiment.

[0027] Figure 10 This is a schematic diagram of the installation structure of the connecting components of the automatic shifting mechanism in this embodiment.

[0028] The reference numerals in the attached figures are as follows:

[0029] 1-Housing assembly; 11-Main housing; 12-Front end cover; 121-Annular groove; 122-Mounting groove; 123-Sealing ring; 124-Dustproof ring;

[0030] 13-Middle seat; 131-First wire guide hole; 14-Rear seat; 141-Guide groove; 1411-Limiting support; 1412-Arc-shaped limiting sleeve; 142-Gland head; 15-Dust cover; 16-Flange; 161-Alignment teeth;

[0031] 2-Motor;

[0032] 3-Hollow shaft; 31-Support platform; 32-End piece; 321-Frustum section; 322-Tube section; 33-First outer ring step; 34-Second outer ring step; 35-Third outer ring step;

[0033] 41-Nut sleeve; 42-Lead screw; 421-Limit pin;

[0034] 51 - First bearing; 52 - Second bearing; 53 - Third bearing;

[0035] 6-Encoder assembly; 61-Detection circuit board;

[0036] 7-Holding brake; 71-Brake plate; 72-Brake pad;

[0037] 8-Connecting assembly; 81-Bearing support seat; 82-Pressure ring; 83-Bolt. Detailed Implementation

[0038] To make the objectives, technical solutions and advantages of this utility model clearer, the following embodiments are provided to further illustrate this utility model in detail.

[0039] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0040] Combination Figures 1 to 3 This embodiment provides an automatic gear shifting mechanism. This mechanism converts the rotational motion of motor 2 into precise linear motion via a lead screw and nut mechanism, thereby driving an external gearbox to perform gear shifting operations. This mechanism has a compact structure, high transmission accuracy, and stable and reliable operation.

[0041] The core of this automatic shifting mechanism is an electric actuator structure that converts rotary motion into linear motion. The foundation of its overall structure is a housing assembly 1, which provides mounting references and protection for the internal components. The housing assembly 1 mainly includes a main housing 11, which is a hollow tubular or cylindrical structure with an internal cavity extending along its axial direction (i.e., length direction) to accommodate the transmission and drive components.

[0042] The drive source is a motor 2. To achieve a high degree of integration and compactness in the structure, this embodiment preferably uses a coreless motor or an external rotor motor, which has an outer stator and an inner rotor. The outer stator, i.e., the stationary part of the motor 2, is fixedly mounted on the inner wall of the main housing 11, for example, by press fitting, bonding, or screw fixing. The inner rotor, i.e., the rotating part of the motor 2, is located radially inside the outer stator, and has an axially hollow part at its center. This design allows the power output shaft to pass through the center of the motor 2, greatly shortening the axial dimension of the entire mechanism.

[0043] A hollow shaft 3 is a key component connecting the motor 2 and the transmission mechanism. It passes through and connects to the axial hollow part of the motor 2, and is fixedly connected to the inner rotor, for example, through a key connection, spline connection, or interference fit, thereby achieving synchronous rotation with the inner rotor. The hollow shaft 3 also has a through-hole in the interior.

[0044] A nut sleeve 41 is installed in the center hole of the hollow shaft 3. The inner wall of the nut sleeve 41 is threaded, and it serves as a transmission conversion element, fitting into the center hole.

[0045] A lead screw 42 is the actuator that ultimately achieves linear motion. It passes through a nut sleeve 41 and forms a threaded drive engagement with the internal thread of the nut sleeve 41. The output end (front end) of the lead screw 42 extends out of the axial front end of the housing assembly 1 and is used to connect to external mechanisms such as shift forks. The end end (rear end) of the lead screw 42 is engaged with the rear end of the housing assembly 1. The purpose of this engagement is to limit the rotation of the lead screw 42, ensuring that the lead screw 42 can only move along its own axial direction.

[0046] When motor 2 is energized, the outer stator generates a rotating magnetic field, driving the inner rotor to rotate. Since the hollow shaft 3 is fixed to the inner rotor, it also rotates synchronously. Furthermore, the nut sleeve 41 also rotates along with the hollow shaft 3. At this time, because the end of the lead screw 42 is limited by the housing assembly 1 and cannot rotate, according to the principle of relative motion, the lead screw 42 will move axially along the thread of the rotating nut sleeve 41, thereby driving the lead screw 42 to achieve linear motion of extension or retraction. This design integrates the motor 2 and the lead screw 42 mechanism coaxially, resulting in a very compact structure, short transmission chain, high efficiency, and precise electronically controlled linear drive.

[0047] This embodiment integrates the motor rotor, the hollow shaft 3 for transmission, the nut sleeve 41, and the linear motion lead screw 42 concentrically in the axial direction within the housing assembly 1, greatly shortening the transmission chain and eliminating intermediate transmission components such as couplings and synchronous belts. This solves the technical problems of bulky structure, low integration, and low transmission accuracy in the prior art, and provides an automatic shifting mechanism with a more compact structure, more direct transmission, and more precise positioning.

[0048] To ensure the stability of the hollow shaft 3 and the nut sleeve 41 under high-speed rotation and axial force, a reliable support and fixing structure is required. In one specific embodiment, refer to... Figure 3The nut sleeve 41 is connected to the inner wall of the central hole of the hollow shaft 3 by a key. Specifically, keyways are machined on the inner wall of the central hole and the outer wall of the nut sleeve 41, and a flat key connects them to transmit torque, ensuring that the nut sleeve 41 can be reliably rotated by the hollow shaft 3. For axial positioning of the nut sleeve 41, a support platform 31 (e.g., an annular step) is integrally formed or separately machined on the inner wall of the central hole of the hollow shaft 3. The bottom end of the nut sleeve 41 presses directly onto this support platform 31 to prevent it from shifting backward in the mechanism.

[0049] To prevent the nut sleeve 41 from shifting forward, the mechanism also includes an end piece 32. This end piece 32 has an axially connected frustum 321 and a tube 322. The tube 322 can precisely extend into the central hole of the hollow shaft 3, and its end face is used to press against the top of the nut sleeve 41. The outer diameter of the frustum 321 of the end piece 32 is larger than that of the tube 322, for connection to the top of the hollow shaft 3, for example, by thread, welding, or screw connection. The end piece 32 also has a through hole at its center for the lead screw 42 to pass through.

[0050] To support the entire rotating assembly (hollow shaft 3, end piece 32, inner rotor, etc.), refer to... Figure 2 and Figure 4 A first bearing 51 is provided. The first bearing 51 is a radial or angular contact ball bearing, the inner ring of which is pressed between the end face of the frustum portion 321 of the end member 32 and the top surface of a first outer ring step 33 on the outer wall of the hollow shaft 3. The first bearing 51 provides precise radial and axial support for the front end of the rotating assembly.

[0051] In conjunction with the first bearing 51, refer to Figure 2 and Figure 5 The housing assembly 1 also includes a front cover 12. The front cover 12 is detachably connected to the front end of the main housing 11 by bolts or the like. A stepped groove is formed on the side of the front cover 12 facing the main housing 11. The stepped groove includes a large-diameter section near the main housing 11 and a small-diameter section adjacent to the large-diameter section. During assembly, the outer ring of the first bearing 51 is precisely accommodated in the large-diameter section, and the stepped surface of the large-diameter section presses against the end face of the outer ring of the first bearing 51, providing axial restraint for the first bearing 51. Furthermore, the inner wall of the large-diameter section can be interference-fitted with the outer ring of the first bearing 51. The small-diameter section is used to accommodate and position the frustum 321 of the end piece 32, serving as a guide and auxiliary support.

[0052] To prevent external contaminants such as dust and moisture from entering the mechanism and to prevent internal lubricant leakage, refer to... Figure 2 and Figure 5The top center of the front cover 12 has a through hole for the lead screw 42 to pass through. One or more annular grooves 121 are formed on the radial inner wall of this through hole for installing a sealing ring 123. Simultaneously, at the outermost end of the through hole, an installation groove 122 is formed for installing a dustproof ring 124 (such as a dustproof scraper). The radial inner lips of both the sealing ring 123 and the dustproof ring 124 are tightly fitted to the outer cylindrical surface of the lead screw 42, forming a dynamic seal and achieving double protection.

[0053] The reliable torque transmission between the nut sleeve 41 and the hollow shaft 3 is ensured by keyed connection and front and rear clamping. The precise fit between the first bearing 51 and the front end cover 12 provides stable and reliable front-end support for the rotating assembly of the hollow shaft 3, guaranteeing smooth and precise transmission. The combined design of the sealing ring 123 and the dustproof ring 124 greatly improves the protection level and environmental adaptability of the mechanism, extending its service life.

[0054] To further enhance the stability of the rotating assembly, a support structure is also provided at the rear end of the hollow shaft 3. (Refer to...) Figure 2 and Figure 6 The housing assembly 1 also includes a center seat 13, which is connected to the axial bottom end (rear end) of the main housing 11. An inner ring step is formed on the inner wall side of the center seat 13. A second bearing 52 is also provided; the top of the inner ring of the second bearing 52 presses against a second outer ring step 34 at the rear end of the hollow shaft 3, while the bottom of its outer ring presses against the top surface of the inner ring step of the center seat 13. Thus, the first bearing 51 and the second bearing 52 support the front and rear ends of the hollow shaft 3 respectively, forming a stable double-support structure.

[0055] Reference Figure 2 and Figure 7 To achieve closed-loop control of the shift mechanism position, an encoder assembly 6 is also integrated into this mechanism. The encoder assembly 6 includes a magnetic ring and a detection circuit board 61. The magnetic ring is a multi-pole magnetized ring magnet, fixedly connected to a third outer ring step 35 on the outer wall of the hollow shaft 3 (typically located near the second bearing 52), and rotates with the hollow shaft 3. The detection circuit board 61 (typically containing a Hall sensor or magnetoresistive sensor array) is fixed to the bottom surface of the inner ring step of the middle seat 13 of the housing assembly 1, directly opposite the magnetic ring.

[0056] When the hollow shaft 3 rotates, the magnetic ring on it also rotates synchronously, causing a periodic change in the magnetic field. A sensor on the detection circuit board 61, facing the magnetic ring, detects this magnetic field change and converts it into an electrical signal (such as a square wave pulse signal). By calculating the number and frequency of the signal pulses, the control system can accurately determine the rotation angle, speed, and direction of the hollow shaft 3, and then calculate the precise linear displacement of the lead screw 42 through the transmission relationship. This dual-bearing support structure significantly improves the rigidity and stability of the rotating system, ensuring smooth operation even under heavy loads. The built-in non-contact encoder assembly 6 provides high-precision position feedback; its simple structure, durability, and resistance to vibration and contamination form the basis for precise gear shifting control.

[0057] As mentioned earlier, in order to effectively convert rotary motion into linear motion, it is necessary to prevent the lead screw 42 from rotating itself. (Refer to...) Figure 8 The rear seat 14 of the housing assembly 1 (the part connected after the middle seat 13) is provided with a guide groove 141 extending parallel to its axial direction. Simultaneously, a limiting pin 421 is radially inserted and fixed at the rear end of the lead screw 42. Both ends of the limiting pin 421 extend out of the lead screw 42 body and fit precisely into the guide groove 141 of the rear seat 14. In this way, a guiding and limiting fit is formed between the limiting pin 421 and the guide groove 141. The limiting pin 421 can only slide along the direction of the guide groove 141, thereby driving the lead screw 42 to achieve axial linear reciprocating motion, while the rotation of the lead screw 42 is completely restricted.

[0058] Continue to refer to Figure 8 To make the guide groove 141 structure more reliable and easier to process and assemble, a modified implementation can be adopted. The bottom end of the rear seat 14 is integrally formed or separately connected to two mutually symmetrical limiting pillars 1411. Notches are machined on both opposite sides of the two limiting pillars 1411. During assembly, two arc-shaped limiting sleeves 1412 (e.g., made of wear-resistant plastic or metal) are respectively inserted into the notches of the two limiting pillars 1411. A precise guide groove, namely the guide groove 141, is naturally formed between the inner arc-shaped surfaces of these two arc-shaped limiting sleeves 1412.

[0059] Reference Figure 1 , Figure 8 and Figure 9 To protect this guide mechanism, a dust cover 15 can also be provided. The dust cover 15 can be a cover that covers the outside of the two limit pillars 1411, and its end is connected to the rear seat 14 by a buckle or screw, which effectively prevents dust and other debris from entering the guide groove 141 and affecting the smooth movement of the lead screw 42.

[0060] The engagement of the limit pin 421 and the guide groove 141 is a simple yet highly effective anti-rotation solution, ensuring the reliability of transmission changes. The guide groove 141 is formed by combining the limit support 1411 and the arc-shaped limit sleeve 1412, simplifying the machining of the rear seat 14. Furthermore, the wear resistance can be improved by replacing the arc-shaped limit sleeve 1412 with one made of a different material, facilitating maintenance. The addition of the dust cover 15 further enhances the reliability and environmental adaptability of the mechanism.

[0061] In certain application scenarios, such as when a vehicle is shifting gears on a slope, or when it is necessary to reliably lock the gear after shifting to prevent the gear from accidentally disengaging due to vibration or external force, this mechanism can also integrate a brake 7, which is preferably a normally closed brake 7.

[0062] For example, refer to Figure 2 , Figure 6 and Figure 9 The brake 7 includes a brake plate 71 and a drive component. The brake plate 71 is a disc-shaped part that is securely connected and fixed to the hollow shaft 3 (e.g., fixed to the rear end of the hollow shaft 3, after the second bearing 52) by multiple screws running radially through it, and rotates with the hollow shaft 3. The drive component is installed in a mounting cavity formed inside the rear seat 14 of the housing assembly 1, facing the brake plate 71. The drive component mainly includes a brake pad 72 driven by an electromagnet.

[0063] Taking the normally closed brake 7 as an example, in the power-off state, the spring (such as a compression spring) inside the drive component is in its natural state, pressing the brake pad 72 firmly against the brake plate 71, generating a huge frictional force, thereby locking the hollow shaft 3 (and the entire rotating system) in place. When the motor 2 needs to work, the electromagnet of the drive component is energized, and the electromagnet generates an attractive force, overcoming the spring force to pull the brake pad 72 back, causing it to disengage from the brake plate 71, thereby releasing the brake and allowing the hollow shaft 3 to rotate freely.

[0064] The normally closed brake 7 provides crucial power-off protection and position locking functions. In the event of an unexpected power outage, the brake 7 will immediately activate, locking the lead screw 42 in its current position to prevent position changes due to loads (such as the back thrust of the gearbox), thus ensuring system safety. After the gear shift is completed, the brake 7 can also be used to lock the position by de-energizing it, reducing the energy consumption and heat generated by continuously powering the motor 2 to maintain its position.

[0065] Reference Figure 1 and Figure 2To facilitate electrical connections and overall machine installation, the housing assembly 1 is designed with corresponding structures. The housing assembly 1 also includes a flange 16, which connects between the center seat 13 and the rear seat 14, or is part of either the center seat 13 or the rear seat 14. A ring of alignment teeth 161 (or locating pin holes, mounting threaded holes) is provided on the radially outer surface of the flange 16. These structures are used for precise alignment and secure installation of the entire automatic shifting mechanism with external equipment (such as the gearbox housing).

[0066] Dedicated cable guide holes are provided to guide and protect the cables of the internal motor 2 and encoder assembly 6. For example, refer to... Figure 7 The middle seat 13 has a first cable pass-through hole 131 for the power supply motor 2 cable to pass through. The flange 16 has at least one second cable pass-through hole for the encoder assembly 6 cable and the motor 2 cable to pass through together. After the cable exits from the inside, at least two gland heads 142 (also called waterproof cable connectors) are provided on the rear seat 14 to achieve reliable fixation and sealing. The gland heads 142 can lock the cable, serving to fix, waterproof, and resist tensile stress.

[0067] As a variation of the implementation, multiple second cable guide holes can be designed to allow different cables to pass through. The number of gland 142s can also be increased or decreased depending on the number of cables.

[0068] The design of the alignment teeth 161 and flange 16 makes the installation of this mechanism standardized, fast, and precise. Separate cable guide holes and integrated gland 142 provide a clear, orderly, and safe wiring path for the cables of the internal electrical components, ensuring the reliability and protection of electrical connection points and avoiding the risk of cable wear or breakage during movement.

[0069] Refer to the output connection structure of the automatic shift mechanism Figure 1 , Figure 2 and Figure 10 The output end of the lead screw 42 requires a standardized interface to connect to the external gearbox shifting mechanism.

[0070] Therefore, the automatic shifting mechanism also includes a bearing support 81, which is fitted onto the output end of the lead screw 42. The bottom of the bearing support 81 (the side facing the main body of the mechanism) forms an annular platform extending radially outward, and its top forms a limiting end extending radially inward. During assembly, the limiting end directly abuts against the foremost front face of the lead screw 42, providing axial positioning for the support.

[0071] A third bearing 53 (typically a thrust bearing or angular contact bearing) is fitted onto the bearing support 81, with the bottom of its inner ring pressing against the limiting end of the support. The outer ring of the third bearing 53 is used to connect external components such as gearbox shift forks. In this way, the axial thrust of the lead screw 42 can be smoothly transmitted to the external load through the bearing support 81 and the third bearing 53.

[0072] Continue to refer to Figure 10 To secure the third bearing 53, a pressure ring 82 is placed on top of the inner ring of the third bearing 53. Finally, a bolt 83 passes through the center hole of the pressure ring 82 and is screwed into the pre-set center threaded hole at the front end of the lead screw 42. By tightening the bolt 83, the pressure ring 82, the inner ring of the third bearing 53, and the bearing support 81 are firmly pressed and fixed to the output end of the lead screw 42.

[0073] The output connection structure of the automatic shifting mechanism provides a robust yet flexible interface. The presence of the third bearing 53 allows the lead screw 42 to transmit significant axial thrust while permitting radial or angular deviations from the external connecting parts, or to allow the external connecting parts to rotate relative to the lead screw 42 when necessary. This protects the lead screw 42 mechanism from off-center loading or jamming, improving the reliability and lifespan of the entire shifting system. The fixing method using bolts 83 and pressure rings 82 facilitates easy assembly, disassembly, maintenance, and replacement.

[0074] It should be understood that although this specification is described according to various embodiments, not every embodiment or implementation method contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0075] The above descriptions are merely illustrative embodiments of this application and are not intended to limit the scope of the embodiments of this application. Any equivalent changes, modifications, and combinations made by those skilled in the art without departing from the concept and principles of the embodiments of this application should fall within the protection scope of the embodiments of this application.

Claims

1. An automatic gear shifting mechanism, characterized in that, include: The housing assembly (1) includes a main housing (11) and has an axially extending receiving cavity formed therein; The motor (2) has an outer stator and an inner rotor. The outer stator is connected to the inner wall of the main housing (11), and the inner rotor has an axially hollow portion. A hollow shaft (3) is inserted through and connected to the axial hollow part of the motor (2), and has a central hole; Nut sleeve (41) is fitted into the central hole; The lead screw (42) passes through the nut sleeve (41) and is threadedly engaged with the nut sleeve (41). Its output end extends out of the axial front end of the housing assembly (1), and its end is limited to the rear end of the housing assembly (1) so that the lead screw (42) only moves axially.

2. The automatic gear shifting mechanism according to claim 1, characterized in that, The nut sleeve (41) is keyed to the inner wall of the central hole, and a support platform (31) is formed in the central hole of the hollow shaft (3), with the bottom end of the nut sleeve (41) pressing on the support platform (31). The automatic shifting mechanism also includes: An end piece (32) is formed with an axially connected frustum (321) and tube (322), the tube (322) extending into the central hole to press the top of the nut sleeve (41), and the frustum (321) being connected to the top of the hollow shaft (3), the end piece (32) having a through hole for the lead screw (42) to pass through; The inner ring of the first bearing (51) is pressed between the frustum portion (321) of the end piece (32) and the top surface of the first outer ring step (33) of the outer wall of the hollow shaft (3).

3. The automatic gear shifting mechanism according to claim 2, characterized in that, The housing assembly (1) includes: The front end cover (12) is connected to one end of the main housing (11) and has a stepped groove formed on the side facing the main housing (11). The stepped groove includes a large diameter section near the main housing (11) and a small diameter section adjacent to the large diameter section. The stepped surface of the large diameter section presses on the outer ring of the first bearing (51), and the small diameter section accommodates the frustum portion (321) of the end piece (32). Furthermore, the top of the front end cover (12) is formed with a through hole for the lead screw (42) to pass through, and the radial inner wall of the through hole is provided with an annular groove (121) for installing a sealing ring (123); the outer end of the through hole is formed with an installation groove (122) for installing a dustproof ring (124), and the radial inner sides of the sealing ring (123) and the dustproof ring (124) are both sealed and fitted with the lead screw (42).

4. The automatic gear shifting mechanism according to claim 1, characterized in that, Also includes: The middle seat (13) of the housing assembly (1) is connected to the axial bottom end of the main housing (11), and an inner ring step is formed on its inner wall side; The second bearing (52) is configured such that the top of its inner ring presses against the second outer ring step (34) of the hollow shaft (3), and the bottom of its outer ring presses against the top surface of the inner ring step.

5. The automatic gear shifting mechanism according to claim 1, characterized in that, Also includes: The encoder assembly (6) includes a magnetic ring and a detection circuit board (61). The magnetic ring is connected to the third outer ring step (35) of the hollow shaft (3), and the detection circuit board (61) is connected to the bottom surface of the inner ring step of the middle seat (13) of the housing assembly (1) and faces the magnetic ring.

6. The automatic gear shifting mechanism according to claim 1, characterized in that, The rear seat (14) of the housing assembly (1) is provided with a guide groove (141) extending parallel to its axial direction; the automatic shifting mechanism further includes: A limiting pin (421) is inserted through the rear end of the lead screw (42) and arranged radially along the lead screw (42). The limiting pin (421) is guided and limited by the guide groove (141) to slide only along the guide groove (141).

7. The automatic gear shifting mechanism according to claim 6, characterized in that, The bottom of the rear seat (14) is provided with two opposing limiting pillars (1411). An arc-shaped limiting sleeve (1412) is respectively inserted into the notch on the opposite sides of the two limiting pillars (1411). The guide groove (141) is formed between the two arc-shaped limiting sleeves (1412). The automatic shift mechanism also includes a dust cover (15) configured to cover the two said limiting pillars (1411) and the end of which is connected to the rear seat (14).

8. The automatic gear shifting mechanism according to claim 1, characterized in that, It also includes a brake (7), which comprises: Brake plate (71), with multiple screws passing through the radial direction of the brake plate (71) and connecting it to the hollow shaft (3); The drive component, which includes an electromagnet-driven brake pad (72), is disposed in the mounting cavity formed by the rear seat (14) of the housing assembly (1) and faces the brake plate (71).

9. The automatic gear shifting mechanism according to claim 1, characterized in that, The flange (16) of the housing assembly (1) connects the middle seat (13) and the rear seat (14), and a ring of alignment teeth (161) is provided on the radial outer side of the flange (16). The middle seat (13) is provided with a first cable pass hole (131) for the cable of the motor (2) to pass through, the flange (16) is provided with at least one second cable pass hole for the cable of the encoder assembly (6) and the cable of the motor (2) to pass through, and the rear seat (14) is provided with at least two gland heads (142) for fixing the cable.

10. The automatic gear shifting mechanism according to claim 1, characterized in that, It also includes a connection assembly (8) that mates with the gearbox, the connection assembly (8) comprising: The bearing support (81) is sleeved on the output end of the lead screw (42), and has an annular platform extending radially outward at its bottom and a limiting end extending radially inward at its top, the limiting end abutting the front end of the lead screw (42). The third bearing (53), the bottom of its inner ring is pressed against the limiting end, for connecting to the external gearbox; A pressure ring (82) is pressed against the top of the inner ring of the third bearing (53); Bolt (83), which is connected to the front end of the lead screw (42) and fixes the pressure ring (82).

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