Double-acting force self-adapting variable speed electric drive system with middle friction

Abstract

The application discloses a kind of middle placement friction type double-acting force self-adapting variable speed electric drive system, with the overall advantages of double-acting force self-adapting variable speed electric drive system, the node of slow gear power return is located in the axial middle part near the inner circle of clutch, the same as the position acting on the second group of elastic members, improve the sensitivity of response, not only simple and compact in structure, further avoid the jamming and delay that can occur in the process of gear shifting, so that the gear shifting of variable speed system is sensitive and will not occur the feeling of jerk;At the same time, the slow gear traction force return position is located near the axial middle part of the driven member, when the resistance increases, the process of clutch separation is compressed all elastic components, not through the release of a group of elastic components, so that the separation of clutch is decisive and rapid, avoid the problem of efficiency reduction caused by excessive friction.

Description

Technical Field

[0001] This invention relates to a motor vehicle transmission, and more particularly to a mid-mounted friction-type dual-force adaptive electric drive system. Background Technology

[0002] The operation of electric vehicles primarily depends on the electric drive system. This system, which deeply integrates mechanical and electric power components, is the core component for driving and provides all the necessary power. The electric drive system mainly consists of four parts: the drive motor, the transmission, the power converter, and the controller. Its performance and efficiency directly affect the electric vehicle's power, economy, and comfort. The size and weight of the drive motor and transmission also affect the overall efficiency of the electric vehicle. The power converter and controller are crucial for the safe and reliable operation of the electric vehicle.

[0003] While an electric drive system with only a reduction gear transmission allows for a direct and smooth torque output from the electric motor, it cannot simultaneously achieve the power and fuel economy of a pure electric vehicle. This is because the drive motor often operates at its highest efficiency point during driving, especially at maximum or minimum speeds and under low load conditions. Due to the large reduction gear ratio, there is no room for further speed increases after reaching the speed limit, causing the electric vehicle to operate at a relatively high critical speed during cruising. Speed ​​is constrained, and efficiency typically drops below 60-70%, resulting in significant power loss, poor high-speed fuel economy, and poor vehicle performance, fuel economy, and comfort. This also severely wastes onboard electrical energy and reduces driving range. Furthermore, an electric drive system with only a reduction gear transmission structure is not conducive to the use of high-efficiency, lightweight drive motors.

[0004] Compared to a purely geared drive system, an electric drive system equipped with a gearbox experiences less power output loss. It provides higher drive torque in the constant torque range and higher speed in the constant power range, achieving high torque and high efficiency under low-speed, heavy-load conditions. Furthermore, it allows for selection of the electric motor's power delivery timing, optimizing the drive motor's power output efficiency, enhancing sustained acceleration performance, and providing a broader high-efficiency platform. This fully meets the requirements of various complex operating conditions, including vehicle acceleration, hill climbing, and high-speed driving, significantly improving power, economy, and comfort. It also offers numerous advantages that are difficult to achieve with a purely geared drive system, such as reduced manufacturing and operating costs, smaller battery capacity, weight reduction, and smaller overall size and weight.

[0005] As products are upgraded and replaced, users are less concerned about performance, efficiency, and range, and less sensitive to weight and cost. Matching variable-speed transmissions should be the future development trend of electric motorcycle transmission systems.

[0006] From 2013 to 2019, several patent documents were published, such as Chinese Patent (ZL 201310389721, title: Multi-cam Adaptive Multi-gear Automatic Transmission, etc.), which discloses various transmission systems using conical friction pairs combined with preload control. This system utilizes the power output of the motor and the properties of driving resistance, through a friction transmission component, an end-face cam clutch mechanism, and an overrunning clutch to change the transmission route, adaptively selecting high or low gears according to the load. The outer surface of the friction transmission component is designed as a conical shape, and the inner ring of the friction ring is constructed as a conical hole structure matching the conical surface. An elastic element located at the right end of the friction transmission component pushes the friction transmission component into the conical hole, achieving power engagement. The end-face cam located at the left end of the friction transmission component, under load, pushes the friction transmission component away from the conical hole, achieving power disengagement. In the end-face cam clutch mechanism described in this document, the part responsible for performing engagement and disengagement consists of the friction transmission component and the elastic element.

[0007] This transmission system breaks through the traditional transmission structure of electric vehicles, but it still has many technical problems:

[0008] 1. In the adaptive cam clutch mechanism, when the load transmitted by the friction pair transmission is equal to or less than the transmitted torque, after the friction pair transmission mechanism components separate, the traction force and driving resistance, which are relative and interact with each other, are converted into a combined axial pressure in the same direction through the transmission mechanism. This pressure is applied to the elastic element disc spring. After the elastic element disc spring is axially compressed, the elastic element's characteristics will cause the elastic force to increase in the opposite direction, while simultaneously pushing back the moving components in the friction pair transmission mechanism. The friction pair may stick together for a short time, making it difficult for the friction pair transmission mechanism to achieve rapid separation and engagement. This will accelerate the wear of the friction pair, leading to uneven shifting and affecting the service life of the friction pair transmission mechanism. In particular, when the relative interaction between the traction force and driving resistance of the friction transmission components increases to be equal to or greater than the transmitted torque limit, the reverse elastic push-back is more prominent. 1. There are engineering and structural problems related to how to reduce the reverse rebound caused by the increased elastic force after the elastic element is compressed; 2. The sequential layout of the friction pair transmission mechanism and the elastic element results in a large space occupation, low power transmission, and low efficiency; 3. The mechanism is complex due to the lack of a transfer mechanism, which is not conducive to lightweighting and integration; 4. The process of calibrating the clutch transmission torque and speed of the friction pair transmission mechanism and the high-efficiency power target of the motor is complex and takes too long; 5. The friction transmission components do not have a mechanism to adapt to the instantaneous and repeated locking under bumpy or washboard roads; 6. The mechanism has engineering problems such as timely synchronous control by the controller.

[0009] Therefore, to solve the above problems, the inventors of this patent improved the aforementioned transmission mechanism by using two sets of transmission elastic elements. In fast gear transmission, the driving resistance acts on the cam pair to push the second set of elastic elements to release the first set of elastic elements (or simultaneously compress the first set of elastic elements), thus disengaging the clutch. In slow gear transmission, the traction force is used to compress the first and second sets of elastic elements (disc springs) through the low-speed cam pair, keeping the clutch disengaged. This fully utilizes the combined effects of traction force and driving resistance. By adopting a friction pair transmission mechanism calibration and adjustment scheme for the transmission load limit, and by abandoning numerous energy-consuming mechanisms, actuators, sensors, and complex algorithms, the transmission mechanism achieves smooth and gentle separation and engagement, transmitting two different power outputs to meet the requirements of various complex operating conditions such as vehicle acceleration, hill climbing, and high-speed driving.

[0010] However, during the testing of the above-mentioned scheme, the inventors discovered that the node position where power is transmitted between the inner ring of the clutch and the transmission shaft sleeve basically coincides with the node position where the traction force of the slow gear mechanism enters. The structure is complex and occupies a large space. Furthermore, both the driving resistance and the traction force need to pass through this power transmission position to reach the second set of elastic elements, causing interference between the power transmission route and the driving resistance and the low gear traction force. Therefore, jamming and delay will occur during gear shifting, resulting in the transmission system being unresponsive and causing a jerking sensation.

[0011] Especially for structures that directly output power using a driveshaft sleeve, the distance between the position where the low-speed driveshaft sleeve transmits the slow-speed traction force back to the inner ring of the clutch and the position acting on the second set of elastic elements is relatively large. This causes the structure to react, resulting in further jamming and delay during gear shifting, making the transmission system less sensitive to gear shifting and causing a jerky feeling.

[0012] Therefore, the aforementioned automatic transmission devices applicable to electric vehicles need to be improved to save space and avoid interference between the power transmission path and driving resistance and low-speed traction. This would prevent jamming and delays during gear shifting, making the transmission system sensitive and free from jerking. At the same time, for friction plate clutches, it is desirable for all friction plates to transmit torque evenly, ensuring long-term use of the system and improving transmission efficiency. Summary of the Invention

[0013] In view of this, the purpose of the present invention is to provide a mid-mounted friction-type dual-force adaptive transmission electric drive system, which adds a reverse gear transmission mechanism with strong adaptability. The device can not only automatically shift gears and change speeds without cutting off the driving force when the driving resistance changes, but also solve the problem of meeting the requirements of high-efficiency forward and reverse driving under complex conditions in both bidirectional driving conditions. Moreover, the device is simple and compact in design, works smoothly and naturally with the cam adaptive automatic transmission mechanism, reduces manufacturing costs, and ensures transmission stability.

[0014] The present invention provides a mid-mounted friction-type dual-force adaptive variable speed electric drive system, comprising a housing and a variable speed system.

[0015] The transmission system includes a power input mechanism, a main shaft, a main drive mechanism, a low-speed transmission mechanism, and a reverse transmission mechanism; the main drive mechanism includes a friction clutch and a drive shaft sleeve fitted around the main shaft; the power input mechanism inputs power to the driving element of the friction clutch; the driven element of the friction clutch transmits power to the drive shaft sleeve; and the drive shaft sleeve outputs power through a power output driving element.

[0016] The driven member of the friction clutch and the drive shaft sleeve, or / and the drive shaft sleeve itself, form a transmission through at least one first axial cam pair.

[0017] The friction clutch is set with an axial preload to engage it. When the drive shaft sleeve outputs power, the first axial cam pair generates an axial component force while transmitting power. This axial component force is opposite to the axial preload and has a tendency to overcome the axial preload and release the friction clutch.

[0018] The low-speed transmission mechanism overtakes the main transmission mechanism during transmission; the drive motor simultaneously transmits power to the low-speed transmission mechanism, which transmits the low-speed power to the driven member of the friction clutch via the second axial cam pair, and the part of the driven member of the friction clutch that receives the low-speed power is located near the axial center of the driven member.

[0019] Furthermore, the low-speed transmission mechanism includes a low-speed gear shaft and an overrunning clutch disposed on the low-speed gear shaft, and also includes a low-speed transmission shaft sleeve that transmits power from the low-speed gear shaft to the driven member of the friction clutch, the low-speed transmission shaft sleeve being provided with at least one second axial cam pair.

[0020] Furthermore, the axial preload is applied by an elastic element, which includes a first elastic element and a second elastic element. The first elastic element applies the axial preload to the friction clutch, and the second elastic element applies a preload to the low-speed transmission shaft sleeve. At the same time, the preload acts on the first elastic element as the basis for applying the preload of the first elastic element. The position of the low-speed transmission shaft sleeve that transmits power to the driven part of the friction plate clutch is located between the first elastic element and the second elastic element.

[0021] Furthermore, the friction clutch is a friction plate clutch, wherein the driving component of the friction plate clutch includes an outer ring and a driving friction plate, and the driven component includes an inner ring and a driven friction plate.

[0022] The outer ring includes a first bracket, a second bracket, and support columns. Multiple support columns are distributed and fixedly connected between the first and second brackets in the circumferential direction. The active friction pad passes through the support columns.

[0023] The inner ring is a hollow cylindrical structure; the first elastic element and the second elastic element are located inside the hollow of the inner ring;

[0024] The rotor of the drive motor has a hollow structure, and the friction plate clutch is located inside the hollow structure of the rotor. The first bracket and the second bracket are fixedly connected to the two axial ends of the rotor to form a transmission engagement.

[0025] Furthermore, the low-speed transmission shaft sleeve extends into the inner ring to form an inner extension section, and the outer surface of the inner extension section is provided with radial protrusions. The first elastic element and the second elastic element are respectively set with preload and are arranged on both sides of the radial protrusions.

[0026] Furthermore, the first elastic element and the second elastic element are respectively the first transmission disc spring and the second transmission disc spring, and the first transmission disc spring and the second transmission disc spring are sleeved on the inner extension section of the transmission shaft sleeve; the inner circle of the inner ring is provided with an inwardly protruding limiting shoulder, and the limiting shoulder is used to block the radial protrusion of the outer surface of the inner extension section in the direction of the first elastic element at a set position.

[0027] Furthermore, the low-speed transmission mechanism also includes a low-speed intermediate drive gear, a low-speed intermediate driven gear, and a low-speed driven gear; the outer ring of the friction plate clutch is in transmission engagement with the low-speed intermediate drive gear, the low-speed intermediate drive gear meshes with the low-speed intermediate driven gear, the low-speed intermediate driven gear is in transmission engagement with the low-speed shaft, the inner ring of the overrunning clutch is in transmission engagement with the low-speed shaft, and the outer ring of the overrunning clutch, as the low-speed drive gear, is in transmission engagement with the low-speed transmission shaft sleeve through the low-speed driven gear.

[0028] Furthermore, the transmission shaft sleeve is rotatably fitted onto the low-speed transmission shaft sleeve; the power output active component is integrally formed or rotatably fitted to form a power output shaft sleeve, the power output shaft sleeve is rotatably fitted onto the transmission shaft sleeve, and the outer circle is rotatably supported on the housing by a bearing; the first bracket forms a necked shape axially outward and is rotatably fitted onto the transmission shaft sleeve.

[0029] The second bracket extends axially outward to form a second bushing segment, which rotates and supports the main shaft and the housing.

[0030] Furthermore, in the friction plate clutch, an elastic preload is formed between adjacent driving friction plates through an elastic pad; the driven friction plates are axially limited by an elastic clip, and an elastic preload is also formed between the driven friction plates through a second elastic pad; the elastic force of the second transmission disc spring is equal to or greater than the elastic force of the first transmission disc spring.

[0031] Furthermore, the elastic pad is an annular pad, and the diameter of the circle in which the support rods are distributed is smaller than the outer diameter of the annular pad but larger than the inner diameter of the annular pad.

[0032] The beneficial effects of this invention are as follows: The mid-mounted friction-type dual-force adaptive transmission electric drive system of this invention possesses all the advantages of a dual-force adaptive transmission electric drive system. It employs two sets of transmission elastic elements, fully utilizing the combined effects of traction force and driving resistance to achieve gear shifting and maintain the corresponding gear under set conditions, transmitting two different power outputs to meet the requirements of various complex operating conditions such as vehicle acceleration, hill climbing, and high-speed driving. Simultaneously, by using the node position between the two sets of elastic elements as the slow-gear power return point, interference between power output and driving resistance and traction force acting on the elastic elements is avoided, and the targets of driving resistance and traction force acting on the elastic elements are made more clearly defined. This not only saves component layout space but also avoids jamming during gear shifting. The delay and other features ensure sensitive and smooth gear shifting without any jerking, thus guaranteeing the power transmission efficiency of the transmission system. Furthermore, this structure allows the power transmission node to be located near the axial center of the inner ring, the same location as the second set of elastic elements, improving responsiveness. This not only results in a simple and compact structure but also further avoids jamming and delays during gear shifting, ensuring sensitive and smooth gear shifting. Simultaneously, by using a slow-gear traction return position located near the axial center of the driven element, the clutch disengagement process, when resistance increases, is achieved by compressing all elastic components, rather than releasing a single set of elastic components. This ensures decisive and rapid clutch disengagement, avoiding efficiency reduction caused by excessive friction. Attached Figure Description

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Figure 1 This is a schematic diagram of the axial cross-sectional structure of the present invention;

[0035] Figure 2 A partial sectional view of the clutch;

[0036] Figure 3 This is a schematic diagram of the installation structure of the active friction pad;

[0037] Figure 4 This is a schematic diagram of the elastic pad structure. Detailed Implementation

[0038] like Figures 1 to 4 As shown: The mid-mounted friction-type dual-force adaptive variable speed electric drive system of the present invention includes a housing (a common structure in the mechanical field, not shown in the figure), a drive motor, and a variable speed system;

[0039] The transmission system includes a main shaft 1, a main transmission mechanism, and a low-speed transmission mechanism. The main transmission mechanism includes a friction clutch and a transmission shaft sleeve 6. The drive motor inputs power to the driving element of the friction clutch, and the driven element of the friction clutch transmits power to the transmission shaft sleeve 6. The driven element, located near its end, transmits power to the transmission shaft sleeve 6. The transmission shaft sleeve 6 outputs power through a power output driving element 3. The power output driving element refers to the element that continues to output power, while the element that receives the power is generally the power output driven element, such as a sprocket or pulley. This makes the present invention a centrally located structure, which will not be described in detail here.

[0040] The driven member of the friction clutch and the drive shaft sleeve 6, or / and the drive shaft sleeve itself, form a transmission through at least one first axial cam pair 601.

[0041] The friction clutch is set with an axial preload to engage it. When the drive shaft sleeve outputs power, the first axial cam pair 601 generates an axial component force while transmitting power. This axial component force is opposite to the axial preload and has a tendency to overcome the axial preload and release the friction clutch.

[0042] The low-speed transmission mechanism overtakes during main transmission, meaning it includes an overtaking clutch. This overtaking clutch overtakes during main transmission and engages during slow gear transmission. The drive motor simultaneously transmits power to the low-speed transmission mechanism, which transmits the low-speed power to the driven member of the friction clutch via the second axial cam pair 401. The portion of the driven member receiving the low-speed power is located near the axial center of the driven member. "Near the axial center" means the driven member has a certain axial length. Slow gear traction is transmitted from the center to the driven member, while the power transmission part of the main transmission mechanism (which is also the output part of the slow gear power) is located at the end of the driven member, thus preventing interference. Combined with the preload of two elastic elements, the clutch disengagement is achieved through elastic compression, ensuring smooth and stable gear shifting.

[0043] In this embodiment, the low-speed transmission mechanism includes a low-speed shaft 7 and an overrunning clutch 8 disposed on the low-speed shaft 7, and also includes a low-speed transmission shaft sleeve 4 that transmits power from the low-speed shaft to the driven member of the friction clutch. The low-speed transmission shaft sleeve 4 is provided with at least one second axial cam pair 401.

[0044] The drive motor simultaneously transmits power to the low-speed shaft 7. In low-speed transmission, the power from the overrunning clutch 8 is transmitted to the driven member of the friction clutch via the second axial cam pair 401. When power is transmitted only through the main transmission mechanism, the power output from the driven member of the friction clutch, after the transmission ratio setting of the low-speed transmission mechanism, is transmitted in the reverse direction (the reverse direction of the second axial cam pair 401 can be a meshing transmission) to the overrunning clutch 8, causing the overrunning clutch 8 to overrun, thereby avoiding transmission interference. When the resistance reaches a set value, the axial component force generated by the first axial cam pair 601 overcomes the axial preload, causing the friction clutch to disengage. Force is transmitted through the low-speed gear shaft to the overrunning clutch and to the second axial cam pair 401, thereby to the driven member of the friction clutch and then to the transmission shaft sleeve 6, outputting slow-speed power. Thus, during slow-speed transmission, the second axial cam transmits the traction force from the slow gear, and the resulting axial component force acts on the friction clutch to overcome the preload. The axial component force generated by the reaction of the driving resistance during the power transmission of the first axial cam pair 601 is also used to overcome the preload. Therefore, the traction force and driving resistance act together on the preload, which has better reliability and better avoids the problem of repeated engagement and disengagement of the friction clutch, making it suitable for driving on roads with poor conditions.

[0045] As shown in the figure, the low-speed transmission shaft sleeve 4 has a segmented structure, with one or more second axial cam pairs 401 between the segments. A second axial cam pair 401 can also be set between the low-speed transmission shaft sleeve 4 and the driven member (middle part). Similarly, with the setting of multiple axial cam pairs, the axial component force acts on the driven member during low-speed transmission, thereby overcoming the axial preload and achieving the function of keeping the clutch disengaged.

[0046] The driving element of a friction clutch can be an outer ring and accessories or an inner ring and accessories, depending on the requirements of the transmission layout. Similarly, the driven element can also be an inner ring and accessories or an outer ring and accessories. Under normal conditions, in order to accommodate the support of the main shaft 1 and the transmission needs of the transmission shaft sleeve, the driven element should be an inner ring and accessories, and the driving element should be an outer ring and accessories.

[0047] As shown in the figure, the driven component of the friction clutch is the inner ring 19. The inner ring 19 is necked to form an extended bushing segment, and the extended bushing segment is used to drive the transmission sleeve 6. Generally, the engagement is formed by a first axial cam pair (which can be a helical cam pair or an end face cam pair). The transmission sleeve 6 itself is a segmented structure, and the segments are connected by one or more first axial cam pairs 601. The multiple cam pairs make the speed change transmission smoother and more stable.

[0048] As shown in the figure, in this embodiment, the inner ring 16 of the friction clutch and the transmission shaft sleeve 6 are connected by a first axial cam pair; the transmission shaft sleeve 6 outputs power through the active power output component (in this embodiment, the active sprocket), and the output shaft sleeve formed by the active power output component is sleeved on the transmission shaft sleeve 6 and connected by transmission (through an axial cam pair, which is generally understood as a first axial cam pair); the axial cam pair here refers to the mutually cooperating axial cams (including end face cams or helical cams). When the transmission shaft sleeve transmits power, the first axial cam pair 601 generates two components in the axial and circumferential directions, of which the circumferential component outputs power, and the axial component is opposite to the axial preload and has the tendency to overcome the axial preload. That is to say, the rotation direction of the axial cam pair (including the second axial cam pair described below) is related to the power output rotation direction. Based on the above description, those skilled in the art, knowing the power output direction, can know which rotation direction of the axial cam pair can apply which axial component force, which will not be elaborated here;

[0049] The active power output component is generally located near the middle of the invention, which is conducive to realizing the layout of the mid-mounted structure. It can transmit power over long distances through a series of mechanical transmission pairs to form a mid-mounted rear-drive structure, etc., which will not be described in detail here.

[0050] In this embodiment, the axial preload is applied by elastic elements, including a first elastic element 10 and a second elastic element 18. The first elastic element 10 applies the axial preload to the friction clutch, and the second elastic element 18 applies a preload to the slow gear transmission sleeve 4. Simultaneously, this preload acts on the first elastic element 10 as the basis for applying the preload of the first elastic element. As shown in the figure, the first elastic element 10 directly applies a leftward preload to the inner ring 16 of the friction clutch, causing the clutch to engage and transmit power. The second elastic element 18 applies a leftward preload to the slow gear transmission sleeve 4 (the sleeve has a corresponding structure, such as an annular protrusion), and simultaneously acts on the first elastic element 10 through the slow gear transmission sleeve 4, forming a stepped linkage structure. In this structure, when the driving resistance reaches a set value, the right end of the transmission sleeve 6 moves towards the first axial cam pair 601. The right-moving compression driven member compresses the first elastic element 10, disengaging the friction clutch. The slow-gear transmission mechanism transmits power, passing the overrunning clutch 8 to the slow-gear transmission shaft sleeve. The slow-gear transmission shaft sleeve compresses the second elastic element 18 via the second axial cam pair, using traction to maintain clutch disengagement while simultaneously transmitting power to the driven member. The driven member transmits power to the transmission shaft sleeve 6, which continues to compress the driven member via the first axial cam pair 601, using driving resistance to maintain clutch disengagement. In this structure, the engagement and disengagement of the clutch are achieved using two elastic elements, allowing the axial force generated by driving resistance to act primarily on a portion of the elastic elements. Clutch disengagement is achieved through a release mechanism, and the stepped, progressive elastic preload buffers the repeated compression of the elastic elements caused by unstable driving resistance on uneven road surfaces, thereby reducing the possibility of repeated clutch engagement and disengagement.

[0051] In this embodiment, the driving component of the friction clutch includes an outer ring and a driving friction plate 14 disposed on the outer ring 17, and the driven component includes an inner ring 19 and a driven friction plate disposed on the inner ring, wherein the inner ring is a hollow cylindrical structure.

[0052] The outer ring of the friction plate clutch includes a first bracket 20, a second bracket 20a, and support columns 17. Multiple support columns 17 are circumferentially distributed and fixedly connected between the first bracket 20 and the second bracket 20a. The active friction plate 14 of the friction plate clutch passes through the support columns. In this structure, the detachable connection of the support columns 17 to the first bracket 20 and the second bracket 20a allows for an adjustable length of the entire outer ring. Different support column lengths can be used to accommodate different needs, resulting in different numbers of active friction plates 14. The active friction plates 14 passing through the support columns ensure stable and uniform movement, making it more suitable for the transmission system of this invention and guaranteeing transmission sensitivity. Simultaneously, the adjustable length provides ample assembly space for the two sets of elastic elements and is suitable for applying preload to longer elastic elements.

[0053] The inner ring of the friction plate clutch is a hollow cylindrical structure; the first elastic element 10 and the second elastic element 18 are located inside the hollow inner ring; as shown in the figure, the main shaft 1 runs through the drive system of the present invention from left to right, forming a supporting foundation, and the main transmission mechanism (the first and second elastic elements and part of the slow gear transmission shaft sleeve) is located in the space formed by the inner ring 19; the drive motor includes a motor stator 22 and a motor rotor 23, which is an inner rotor structure, as shown in the figure. The rotor of the drive motor is a hollow structure, and the friction plate clutch is located inside the hollow structure of the rotor. The first bracket and the second bracket are respectively fixedly connected to the two axial ends of the rotor to form a transmission fit; this structure makes the electric drive system compact overall, occupying less space during use. The hollow inner ring 19 can transmit a large torque and is used to install some components, so that the structure of the clutch and the transmission mechanism is deeply optimized, forming partial or complete containment and high integration, smooth and natural cooperation, and no operational interference, ensuring that the transmission mechanism works efficiently under all working conditions and comprehensive road conditions.

[0054] As shown in the figure, the first bracket extends outward (e.g.) Figure 1 As shown, the first bushing segment extends to the left (relative to the clutch) and the second bracket extends to the right (as shown) to form the second bushing segment. The transmission bushing 6 is rotatably fitted onto the low-speed transmission bushing 4. The first bushing segment is rotatably fitted onto the transmission bushing 6, and the low-speed intermediate drive gear 5 is rotatably fitted onto the first bushing segment. As shown, the inner ring 19 is necked to form an inner ring bushing and engages with the transmission bushing 6 through a first axial cam pair 601. The inner ring bushing and the transmission bushing 6 are rotatably fitted onto the low-speed transmission bushing 4. In the above structure, each bushing is fitted into the inner ring in sequence and rotates or engages as needed. It has good support stability and a simple and compact structure. It can be achieved through a simple mechanical connection, which will not be elaborated here.

[0055] The second bushing section is rotatably supported by the main shaft 1 and the housing, such as Figure 1As shown, the second bushing extends to the right (based on the left and right of the structure shown in the figure) to form a set shape, forming a stepped necking structure between the axial direction and the second bracket 20a. The set part of the outer circle is supported by the housing (not marked in the figure) by a bearing, and the set part of the inner circle is supported by the main shaft 1. Of course, the way it is supported by the main shaft 1 generally needs to be achieved through an intermediate component. As shown in the figure, the inner circle is supported by the main shaft 1 by a bearing and a bearing support 11 (the bearing support 11 also serves as the base for the second elastic element), forming a support structure. The overall structure is stable, and will not be described in detail here. The structure of the bearing support 11 is adapted to the structure of the main shaft 1, the second bushing, and other components. The bearing support 1 and the main shaft 1 are circumferentially... The structure can be fixed, for example, through a spline structure, forming a stable support, which will not be elaborated here. At the same time, the first and second supports are partially made into bushing structures, and ultimately the main housing and the power output shaft form direct and indirect support, transferring the additional bending moment generated by the torque to the housing. It can transmit a large torque without bending deformation, which can greatly reduce the size of the components under the same load-bearing capacity conditions and adapt to the hollow structure of the clutch. It achieves high torque, high speed and lightweight indicators, and also makes the transmission mechanism have good smoothness and low noise at high speed. This structure ensures the compactness of the overall structure of the drive system itself, which is conducive to the lightweight layout of the entire drive system.

[0056] In this embodiment, the low-speed transmission shaft sleeve 4 extends into the inner ring 19 to form an inner extension section. The outer surface of the inner extension section is provided with a protrusion 16. The first elastic element 10 and the second elastic element 18 are respectively set with preload and are arranged on both sides of the protrusion. As shown in the figure, the protrusion 16 is an annular protrusion, which is used to separate the first elastic element 10 and the second elastic element 18. One end of the first elastic element abuts against the annular protrusion, and the other end abuts against the preload limiting shoulder formed by the inner ring necking. One end of the second elastic element abuts against the annular protrusion, and the other end abuts against a retaining ring sleeved on the main shaft. The retaining ring abuts against the bearing support 11. This is a general structure in the mechanical field, forming a complete speed change elastic mechanism.

[0057] In this embodiment, the first elastic element 10 and the second elastic element 18 are respectively the first and second transmission disc springs. The first transmission disc spring is sleeved on the inner extension section of the transmission shaft sleeve, and the second transmission disc spring is also sleeved on the inner extension section of the transmission shaft sleeve. Of course, the inner extension section can also end with the radial protrusion 16, and the second transmission disc spring can directly abut against the radial protrusion 16, which will not be elaborated here. The inner circle of the inner ring 19 is provided with an inwardly protruding limiting shoulder. The limiting shoulder is used to block the radial protrusion on the outer surface of the inner extension section in the direction of the first elastic element at a set position. As shown in the figure, the limiting shoulder forms a radially inward step to block the annular protrusion, so as to ensure that the first elastic element 10 can withstand the pressure of the second elastic element 18 to a limited extent, and can conveniently set the preload of the second elastic element. At the same time, the preload can be applied in a stepwise manner, and the axial preload can be smoothly released when the driving resistance reaches the set value.

[0058] As shown in the figure, the low-speed transmission mechanism also includes a low-speed intermediate drive gear 5, a low-speed intermediate driven gear 9, and a low-speed driven gear 2. The outer ring of the friction plate clutch is in transmission engagement with the low-speed intermediate drive gear 5. The low-speed intermediate drive gear 5 meshes with the low-speed intermediate driven gear 9. The low-speed intermediate driven gear 9 is in transmission engagement with the low-speed shaft 7. The inner ring of the overrunning clutch is in transmission engagement with the low-speed shaft. The outer ring of the overrunning clutch 8 serves as the low-speed drive gear and meshes with the low-speed driven gear 2. Of course, this outer ring is an external gear ring structure, which will not be described in detail here. The low-speed driven gear 2 is in transmission engagement with the low-speed transmission shaft sleeve 4 (in this embodiment, it is a sleeve and transmission engagement). The overall structure is simple and compact, and the transmission route is clear and unambiguous. The transmission engagement between the gears and shafts can be achieved through general transmission engagement structures, such as keyed connections or integral molding, which will not be described in detail here.

[0059] Based on this structure, it can be concluded that the position of the overrunning clutch can be arbitrarily selected within the low-speed gear mechanism. For example, it can be used as the low-speed gear intermediate driving gear 5, the low-speed gear intermediate driven gear 9, and the low-speed gear driven gear 2 to achieve the purpose of the invention, which will not be elaborated here.

[0060] As shown in the figure, the active power output component 3 is sleeved on the transmission shaft sleeve 6 and located inside the low-speed driven gear 2 near the middle, making it possible for the present invention to have a centrally located output structure; the active power output component 3 forms a power output shaft sleeve for receiving the output power of the transmission shaft sleeve 6 and transmitting it to the active power output component 3, and the power output shaft sleeve is sleeved on the transmission shaft sleeve 6 with transmission fit and its two ends respectively forming rotational supports with the housing;

[0061] Unlike existing power output connection transmissions, this structure uses a power output shaft sleeve to output power to the sprocket. It has the required set length in the axial direction and its inner circle is supported by the transmission shaft sleeve 6, providing uniform and stable support. The outer circle is supported by the housing, and together with the inner circle of the transmission shaft sleeve 6, it forms stable support from both the inner and outer sides. Theoretically, it can be infinitely enlarged in the axial direction, thereby making the sprocket installation stable, avoiding running gaps, ensuring transmission efficiency, and ensuring installation support strength.

[0062] In this invention, in addition to bearing support, oil passages or oil grooves are provided at the rotating parts to reduce friction in order to ensure the compactness of the structure and the stability of the support. This is a common configuration in the field of mechanical transmission and will not be described in detail here.

[0063] The friction clutch has an elastic preload between adjacent driving friction plates via an elastic pad; the driven friction plate is axially limited by an elastic clip.

[0064] Structurally, the transmission shaft sleeve 6 is rotatably fitted onto the low-speed transmission shaft sleeve 4, and the low-speed intermediate drive gear 5 is either driven or fixedly mounted on a low-speed intermediate drive gear sleeve. The low-speed intermediate drive gear sleeve and the first sleeve section of the first bracket 20 are rotatably fitted onto the transmission shaft sleeve 6. The transmission shaft sleeves are layered and rotated together, and the overall structure is compact and mutually supportive, giving the structure good stability.

[0065] In this embodiment, an elastic preload is formed between adjacent active friction plates 14 of the friction plate clutch via an elastic pad 13. The elastic pad 13 is generally made of an elastic non-metallic material and has a set elasticity. As shown in the figure, the elastic pad is an annular pad. The diameter of the circle in which the support rods are distributed is smaller than the outer diameter of the annular pad but larger than the inner diameter of the annular pad, meaning the support rods need to pass through the elastic pad. Figure 4As shown, the elastic pad 13 is an annular elastic ring made of polyurethane material. The annular elastic ring has a hole for the support column 17 to pass through, ensuring the installation stability of the elastic pad 13. The elastic pad 13 is arranged between adjacent active friction plates 14. When the active friction plate 14 is compressed, it overcomes the elastic force of the elastic ring and engages with the driven friction plate for transmission. When the pressure is released, the elasticity of the elastic ring makes the active friction plate 14 return to its position evenly and quickly, completing the shifting operation. At the same time, due to the setting of the elastic pad 13, each active friction plate is evenly stressed, and there is synchronicity when engaging and disengaging with the driven friction plate, avoiding some friction plates being in a half-friction state and affecting efficiency. Since the annular area of ​​the elastic pad covers the support rod, the area of ​​the elastic pad acting on the active friction plate is increased, ensuring uniformity while ensuring the sensitivity of the clutch engagement and disengagement. Combined with the preload structure of the double elastic element of the present invention, the friction clutch is further adapted to the disengagement and engagement characteristics of the transmission mechanism of the present invention.

[0066] The driven friction plate 12 is axially limited by the elastic retaining ring 15, such as Figure 2 As shown, the cross-section of the elastic retaining ring 15 can be rectangular, circular, etc., and it is installed in the mounting groove corresponding to the inner ring 19 to limit the driven friction piece 12, so as to ensure that the movement of the inner ring 19 can drive the driven friction piece to move more flexibly and smoothly, and complete the engagement and separation smoothly.

[0067] Meanwhile, the outer and inner ring loads of the clutch are both made into necked bushing structures, and are ultimately supported by the housing and main shaft (indirectly). The additional bending moment generated by the torque is transferred to the housing, which can transmit a large torque without bending deformation. This can greatly reduce the size of the components under the same load-bearing capacity and adapt to the hollow structure of the clutch. It achieves high torque, high speed and lightweight performance, and also makes the transmission mechanism have good stability and low noise at high speed. This structure ensures the compactness of the overall structure of the drive system itself, which is conducive to the lightweight layout of the entire drive system.

[0068] In this embodiment, the spring force of the second speed-changing disc spring is equal to or greater than that of the first speed-changing disc spring to ensure the clamping force on the first disc spring, thereby ensuring the normal operation of the system.

[0069] The above embodiments are merely the optimal structures of the present invention and are not intended to limit the scope of protection of the present invention; adjustments to the connection method do not affect the achievement of the purpose of the present invention.

[0070] The power transmission route for the high gear in this embodiment is as follows:

[0071] Drive motor rotor → outer ring of friction clutch → inner ring of friction clutch → transmission shaft sleeve → first axial cam pair → transmission shaft sleeve → active power output component → output power;

[0072] At this point, the overrunning clutch overtakes, and the resistance transmission route is: active power output component → drive shaft sleeve → first axial cam pair → drive shaft sleeve → inner ring of friction clutch → first transmission disc spring (which also exerts pressure on the second transmission disc spring); when the driving resistance increases to a certain level, the resistance causes the axial force of the first axial cam pair to overcome the first transmission disc spring (which also exerts pressure on the second transmission disc spring), causing the inner ring of the friction clutch to move, thereby disengaging the friction clutch. Power is then transmitted through the following route, i.e., the low-speed gear power transmission route:

[0073] Drive motor rotor → outer ring of friction clutch → low speed shaft → overrunning clutch → low speed driven gear → low speed transmission shaft sleeve → second axial cam pair → middle part enters the inner ring of friction clutch → transmission shaft sleeve → first axial cam pair → active power output component → output power.

[0074] In the low-speed power transmission route, the axial force (driving resistance) generated by the first axial cam pair continues to act on the first transmission disc spring, while the axial force (traction force) of the second axial cam pair acts on the second transmission disc spring. Both are compression (i.e., in the direction of clutch disengagement). That is, in the low-speed power transmission process, the low-speed traction force and driving resistance work together to prevent the compression of the transmission disc spring during the low-speed transmission process, thereby preventing the clutch from repeatedly engaging during the low-speed power transmission process.

[0075] As can be seen from the above transmission route, when the present invention is running, the clutch is tightly engaged under the action of the first and second transmission disc springs, forming an automatic transmission mechanism that maintains a certain pressure to achieve the purpose of transmission. At this time, the overrunning clutch is in the overrunning state.

[0076] When a vehicle starts, the resistance is greater than the driving force. This resistance forces the first axial cam pair to undergo axial displacement, compressing the first transmission disc spring and disengaging the clutch. This automatically enables low-speed starting, shortening the starting time and reducing the starting force. Simultaneously, the second transmission disc spring is compressed based on the aforementioned principle. At the same time, both the first and second transmission disc springs absorb the energy of the motion resistance torque, storing potential energy for resuming power transmission in higher gears.

[0077] After successful startup, the driving resistance decreases. When the axial force decreases to less than the pressure generated by the first transmission disc spring (while the second transmission disc spring is compressed), the pressure of the transmission disc spring is released due to compression caused by the motion resistance. Under the push of the first transmission disc spring, the inner ring is compressed and pushed to complete the clutch to return to a tight engagement state, and the low-speed overrunning clutch is in an overrunning state.

[0078] During operation, the automatic gear shifting principle is the same as above, which achieves gear shifting without cutting off the driving force, making the entire locomotive run smoothly, safely and with low energy consumption, and simplifying the transmission route and improving transmission efficiency; of course, at this time, the reverse gear overtakes the clutch without interfering with normal driving.

[0079] Finally, 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, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A mid-mounted friction-type dual-force adaptive variable speed electric drive system, characterized in that: Includes the housing, drive motor, and transmission system; The transmission system includes a main shaft, a main transmission mechanism, and a low-speed transmission mechanism; the main transmission mechanism includes a friction clutch and a transmission shaft sleeve, the drive motor inputs power to the driving element of the friction clutch, the driven element of the friction clutch transmits power to the transmission shaft sleeve, and the transmission shaft sleeve outputs power through a power output driving element; The driven member of the friction clutch and the drive shaft sleeve, or / and the drive shaft sleeve itself, form a transmission through at least one first axial cam pair. The friction clutch is subjected to an axial preload by an elastic element to engage it. When the transmission shaft sleeve outputs power, the first axial cam pair generates an axial component force while transmitting power. This axial component force is opposite to the axial preload force and has a tendency to overcome the axial preload force and release the friction clutch. The low-speed transmission mechanism overtakes the main transmission mechanism during transmission; the drive motor simultaneously transmits power to the low-speed transmission mechanism, which transmits the low-speed power to the driven member of the friction clutch via the second axial cam pair, and the part of the driven member of the friction clutch that receives the low-speed power is located near the axial center of the driven member. The friction clutch is a friction plate clutch. The driving component of the friction plate clutch includes an outer ring and a driving friction plate, and the driven component includes an inner ring and a driven friction plate. The outer ring includes a first bracket, a second bracket, and support columns. Multiple support columns are distributed and fixedly connected between the first and second brackets in the circumferential direction. The active friction pad passes through the support columns. The inner ring is a hollow cylindrical structure; the first elastic element and the second elastic element are located inside the hollow of the inner ring; The rotor of the drive motor has a hollow structure, and the friction plate clutch is located inside the hollow structure of the rotor. The first bracket and the second bracket are respectively fixedly connected to the two axial ends of the rotor to form a transmission engagement. The low-speed transmission mechanism further includes a low-speed intermediate drive gear, a low-speed intermediate driven gear, and a low-speed driven gear; the outer ring of the friction plate clutch is in transmission engagement with the low-speed intermediate drive gear, the low-speed intermediate drive gear meshes with the low-speed intermediate driven gear, the low-speed intermediate driven gear is in transmission engagement with the low-speed shaft, the inner ring of the overrunning clutch is in transmission engagement with the low-speed shaft, and the outer ring of the overrunning clutch, as the low-speed drive gear, is in transmission engagement with the low-speed transmission shaft sleeve through the low-speed driven gear; The elastic element includes a first elastic element and a second elastic element. The first elastic element applies the axial preload to the friction clutch, and the second elastic element applies a preload to the low-speed transmission shaft sleeve. At the same time, the preload acts on the first elastic element as the basis for applying the preload of the first elastic element. The position of the low-speed transmission shaft sleeve that transmits power to the driven part of the friction plate clutch is located between the first elastic element and the second elastic element.

2. The mid-mounted friction-type dual-force adaptive variable speed electric drive system according to claim 1, characterized in that: The low-speed transmission mechanism includes a low-speed shaft and an overrunning clutch disposed on the low-speed shaft, and also includes a low-speed transmission shaft sleeve that transmits power from the low-speed shaft to the driven member of the friction clutch, the low-speed transmission shaft sleeve being provided with at least one second axial cam pair.

3. The mid-mounted friction-type dual-force adaptive variable speed electric drive system according to claim 1, characterized in that: The low-speed transmission shaft sleeve extends into the inner ring to form an inner extension section. The outer surface of the inner extension section is provided with radial protrusions. The first elastic element and the second elastic element are respectively set with preload and are arranged on both sides of the radial protrusions.

4. The mid-mounted friction-type dual-force adaptive variable speed electric drive system according to claim 3, characterized in that: The first elastic element and the second elastic element are respectively the first speed change disc spring and the second speed change disc spring. The first speed change disc spring and the second speed change disc spring are sleeved on the inner extension section of the transmission shaft sleeve. The inner circle of the inner ring is provided with an inwardly protruding limiting shoulder. The limiting shoulder is used to block the radial protrusion on the outer surface of the inner extension section in the direction of the first elastic element at a set position.

5. The mid-mounted friction-type dual-force adaptive variable speed electric drive system according to claim 1, characterized in that: The transmission shaft sleeve is rotatably fitted onto the low-speed transmission shaft sleeve; the power output active component is integrally formed or rotatably fitted to form a power output shaft sleeve, the power output shaft sleeve is rotatably fitted onto the transmission shaft sleeve, and the outer circle is rotatably supported on the housing by a bearing; the first bracket forms a necked shape axially outward and is rotatably fitted onto the transmission shaft sleeve. The second bracket extends axially outward to form a second bushing segment, which rotates and supports the main shaft and the housing.

6. The mid-mounted friction-type dual-force adaptive variable speed electric drive system according to claim 4, characterized in that: The friction disc clutch has an elastic preload formed between adjacent driving friction discs by an elastic pad; the driven friction discs are axially limited by an elastic clip, and the driven friction discs are also connected by a second elastic pad to form an elastic preload; the elastic force of the second transmission disc spring is equal to or greater than the elastic force of the first transmission disc spring.

7. The mid-mounted friction-type dual-force adaptive variable speed electric drive system according to claim 6, characterized in that: The elastic pad is an annular pad, and the diameter of the circle in which the support rods are distributed is smaller than the outer diameter of the annular pad but larger than the inner diameter of the annular pad.

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