Loaded planetary traction drive

Abstract

This invention discloses a loading-type planetary traction drive, in which a wedge-shaped loading space is formed on both sides of the radial distance circumferential direction between the planetary rollers and the outer ring. A loading roller, located within the wedge-shaped loading space and in rolling contact with the planetary rollers and the outer ring, is provided with an initial preload towards the radial distance. Both the planetary rollers and the loading roller are floating, and the loading roller transmits power to the planetary carrier. The torque or reaction torque transmitted by this invention can act directly on the loading roller, achieving adaptive loading and making the loading process faster and more flexible. Optimization of the load in the contact area can also improve the service life of the traction drive. The superposition of contact forces can generate a larger clamping force, thereby enabling each contact area to generate sufficient tangential force to transmit power. Furthermore, the planetary traction drive provided by this invention can achieve high-load transmission under the load-sharing effect of multiple rollers, and the zero-spin design based on cylindrical rollers can also minimize power loss and improve transmission accuracy and efficiency.

Description

Technical Field

[0001] This invention relates to the field of traction planetary transmissions, specifically a loading-type planetary traction drive. Background Technology

[0002] With the trend of electrification and the development of new motor technologies, the trend towards higher-speed motors is becoming increasingly apparent. Maximizing the efficiency of energy-consuming equipment and improving motor drive systems hold immense potential for energy conservation. Compared to traditional motors, high-speed motors, combined with compact and efficient mechanical transmission devices, can achieve miniaturization, weight reduction, and high power density in power systems, lowering costs and reducing the motor's dependence on rare earth resources, thus showing broad prospects. However, in the high-speed, heavy-load field, traditional gear transmissions pose significant challenges to manufacturing costs, gear fatigue life, and NVH suppression, presenting new boundaries and constraints for electrification development. Traction drives, on the other hand, utilize the shear force of oil film between adjacent components or the frictional force generated by direct contact to transmit power.

[0003] Since the rollers do not make direct contact with each other under high-speed conditions, traction drives have certain inherent advantages over gears, including high efficiency, zero backlash, low vibration, small angular velocity fluctuation, simple design and manufacturing, and great potential for high and ultra-high speeds. Furthermore, they can solve the NVH problem of high-speed gear transmission in principle, and therefore are expected to become an ideal choice for more new demands and applications.

[0004] Therefore, patent CN111868413A (Ultimate Transmissions) discloses a planetary traction scheme that adopts a loading roller structure. Two loading rollers are symmetrically distributed on both sides of each planetary roller, which can realize bidirectional transmission. The planetary carrier contacts the bearings on both sides of the planetary roller. During operation, the tangential force at the contact point between the planetary roller and the outer ring causes the loading roller to enter the wedge-shaped space, thereby wedging and loading. However, this structure still does not change the structure of the planetary roller transmitting load. The wedging process of the loading roller is not directly coupled with the load, and the passive wedging loading also reduces the responsiveness of the system. It is not direct or flexible in its adaptation to speed, load, and load.

[0005] Therefore, in order to meet the requirements of high-speed heavy-duty drives, a planetary traction drive is needed that can achieve high efficiency, high load, zero spin transmission, and direct and flexible adaptability of the loading roller wedging process relative to the load. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to overcome the defects in the existing design and provide a loaded planetary traction drive that can achieve high efficiency, high load, zero spin transmission, and the wedging process of the loading roller can be directly and flexibly adaptive relative to the load.

[0007] The loading-type planetary traction actuator of the present invention includes a sun gear, an outer ring, a planet carrier, and planetary rollers evenly distributed circumferentially between the sun gear and the outer ring; the planetary rollers are in rolling contact with the sun gear and have a radial distance between them and the outer ring, thereby forming a wedge-shaped loading space on both sides of the radial distance circumferential direction between the planetary rollers and the outer ring.

[0008] It also includes a loading mechanism, which includes a loading roller located within a wedge-shaped loading space and in rolling contact with the planetary roller and the outer ring, the loading roller being provided with an initial preload toward the radial pitch;

[0009] Both the planetary rollers and the loading rollers are floating, and the loading rollers transmit power to the planet carrier.

[0010] Furthermore, the loading rollers are provided in the loading spaces on both sides of the radial spacing, and the initial preload is provided in each of them.

[0011] Furthermore, the planetary carrier rotates coaxially with the outer ring, and the loading roller is mounted on the planetary carrier via a loading roller shaft and transmits power to the planetary carrier.

[0012] Furthermore, the planetary carrier is provided with a loading roller groove in the circumferential direction, and the loading roller shaft is floatingly disposed in the loading roller groove and abuts against the side wall of the loading roller groove in the transmission direction, thereby transmitting power to the planetary carrier in a direction away from the radial distance.

[0013] Furthermore, the loading roller groove is set on the planetary carrier corresponding to the radial spacing, and the two loading rollers on both sides of the same radial spacing are respectively set at both ends of the circumferential direction of the loading roller groove. The initial preload of the loading roller is applied to the loading roller shaft by the side wall of the loading roller groove.

[0014] Furthermore, the initial preload is applied by an elastic element or elastic layer provided on the sidewall of the loading roller groove;

[0015] Alternatively, a loading groove is provided on the planetary carrier adjacent to the loading roller groove, and the sidewall of the loading groove is adjacent to the sidewall of the loading roller groove; the initial preload is formed by applying pressure to the sidewall of the loading roller groove within the loading groove, causing elastic deformation of the sidewall of the loading roller groove; the elastic deformation of the sidewall of the loading roller groove is formed by a bidirectional bolt pair within the loading groove, or by a pressure spring within the loading groove.

[0016] Furthermore, the planetary carrier includes a left end plate and a right end plate, each of which is provided with a loading roller groove. The two ends of the loading roller shaft are respectively floatingly disposed in the loading roller grooves of the left end plate and the right end plate, so that the planetary roller is floatingly located between the left end plate and the right end plate.

[0017] Furthermore, the loading roller groove is disposed on the outer circle of the left and right end plates; or, the left and right end plates are annular structures, and the loading roller groove is located on the inner circle of the annular structure; or, the left and right end plates are each composed of separate components, and the loading roller groove is formed between adjacent separate components.

[0018] Furthermore, the sun gear and the outer ring are coaxial;

[0019] Alternatively, the sun gear and the outer ring are eccentrically positioned, and the diameters of the planetary rollers differ to accommodate the eccentric structure between the sun gear and the outer ring.

[0020] Furthermore, the planetary rollers are a single-layer planetary roller structure arranged along the circumference;

[0021] Alternatively, the planetary rollers are in multiple sets, and the multiple sets of planetary rollers are arranged to form a multi-layered planetary roller structure along the radial direction. Rolling contact is formed between different sets of planetary rollers, and the loading roller is located between the outermost set of planetary rollers and the outer ring.

[0022] Alternatively, the planetary rollers can be an axial stepped structure and there are multiple sets of them. The multiple sets of planetary rollers are arranged to form a radial multi-layer planetary roller structure. The minor and major diameters of the planetary rollers in different sets form rolling contact in the radial direction. The loading roller is located between the planetary rollers of the outermost planetary roller set and the outer ring.

[0023] The beneficial effects of this invention are as follows: The loading-type planetary traction drive of this invention has a loading roller between the outer ring and the planetary rollers. Therefore, the transmitted torque or reaction torque can directly act on the loading roller, so that the loading roller actively weds under the combined action of the tangential force at the contact point between the planetary roller and the outer ring and the contact force at the inner wall of the planetary carrier slot, generating a clamping force related to the load. This achieves adaptive loading and makes the loading process faster and more flexible. The optimization of the load in the contact area can also improve the service life of the traction drive. The superposition of the contact forces can generate a larger clamping force, thereby enabling each contact area to generate sufficient tangential force to transmit power. In addition, the planetary traction drive provided by this invention can achieve high-load transmission under the load-sharing effect of multiple rollers. The zero-spin design based on the cylindrical rollers can also minimize power loss and improve transmission accuracy and transmission efficiency. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a cross-sectional structural diagram of the present invention;

[0027] Figure 3 This is a schematic diagram of the exploded structure of the present invention;

[0028] Figure 4 Schematic diagram of a loading roller groove structure for the outer circle of a planetary carrier;

[0029] Figure 5 A schematic diagram of a loading roller groove structure for the inner circle of a planetary carrier ring;

[0030] Figure 6 This is a schematic diagram of the split planetary carrier structure of the present invention;

[0031] Figure 7 This is a schematic diagram illustrating the adjustment of preload using elastic elements or elastic pads;

[0032] Figure 8 This is a schematic diagram of a structure that uses a spring to adjust the preload.

[0033] Figure 9 This is a schematic diagram of a mechanism that uses a screw to adjust the preload.

[0034] Figure 10 This is a schematic diagram of the multi-layer planetary roller arrangement of the present invention;

[0035] Figure 11 This is a schematic diagram of the eccentric arrangement of the present invention;

[0036] Figure 12 This is a schematic diagram of the multi-layer stepped planetary roller arrangement of the present invention. Detailed Implementation

[0037] As shown in the figure, the loading-type planetary traction drive of this embodiment includes a sun gear 1, a planet carrier 5, an outer ring 4, and planetary rollers 2 evenly distributed circumferentially between the sun gear 1 and the outer ring 4; the planetary rollers are in rolling contact with the sun gear 1 and form a radial distance between them and the outer ring 4, thereby forming a wedge-shaped loading space on both sides of the circumferential direction between the planetary rollers 1 and the outer ring 4 at the radial distance.

[0038] It also includes a loading mechanism, which includes a loading roller 3 located within a wedge-shaped loading space and in rolling contact with the planetary roller 2 and the outer ring 4, the loading roller being provided with an initial preload toward the radial spacing;

[0039] Both the planetary rollers 2 and the loading rollers 3 are floating, and the loading rollers transmit power to the planetary carrier 5. As shown in the figure, the loading roller 3's direction away from the radial distance refers to the side of the loading roller 3 that is circumferentially away from the radial distance, which will not be elaborated further here. Thus, the load on the planetary carrier acts directly on the loading rollers, avoiding the problem of the loading rollers not directly responding to the load in patent CN111868413A. The initial preload can be the preload pressure formed by the elastic element, or it can be a directly formed initial preload, causing the loading roller 3 to move towards the radial distance. "Floating" refers to the installation state, that is, except for the necessary driving rolling and transmission of load and movement. There are no special restrictions on the degrees of freedom. For example, the planetary rollers are simply positioned between the sun gear and the loading rollers without any other installation restrictions. The loading rollers are simply positioned between the planetary rollers and the outer ring, and apart from being subjected to an initial preload and needing to drive the planet carrier to rotate, there are no other installation restrictions. Rolling refers to rotation around its own axis, which will not be elaborated here. At the same time, unless otherwise specified, the circumferential direction of this invention refers to the circumferential direction of the outer ring, which will not be elaborated here. The way the loading rollers transmit power to the planet carrier 5 can limit the loading rollers in the driven direction when the planet carrier is set up, thus driving the planet carrier when it is driven to revolve by the planetary rollers, which will not be elaborated here.

[0040] like Figure 1 As shown, the sun gear 1, planetary rollers 2, and outer ring 4 form a traction-type planetary transmission gear system, arranged in the existing planetary transmission structure, which will not be described in detail here. A loading roller 3 is provided between the planetary rollers and the outer ring, meaning the loading roller participates in forming the planetary traction transmission gear system. The planetary rollers 2 are evenly distributed along the circumference, contacting the sun gear 1 and the loading rollers 3 and achieving rotation and revolution. The loading rollers 3 are confined by a loading mechanism to move freely within the wedge-shaped space formed by the planetary rollers 2 and the outer ring 4, and simultaneously interact with the planetary rollers. The planetary roller 2 contacts the outer ring 4; the sun gear 1, planetary roller 2, and loading roller 3 are all designed with axial limiting to prevent axial movement, and the planetary roller 2 and loading roller 3 are both floating, thereby achieving uniform loading in each contact area; in this embodiment, the sun gear 1 and the outer ring 4 are coaxial and rotate freely around the central axis; during operation, the loading roller 3 wedges into the convergence gap between the planetary roller 2 and the outer ring 4 to generate a suitable normal load, thereby generating sufficient tangential force in each contact area to transmit power;

[0041] In the above structure, rolling contact pairs are formed between the sun gear 1 and the planetary roller 2, between the planetary roller 2 and the loading roller 3, and between the loading roller 3 and the outer ring 4. The rolling contact pairs can be formed by direct contact between adjacent components to form a friction transmission fit, or by adding traction oil so that adjacent components form a traction transmission fit through oil film shear force.

[0042] In this embodiment, the loading rollers 3 are provided in the loading spaces on both sides of the radial spacing, and the initial preload is provided in both sides; that is, the loading rollers 3 are symmetrically distributed on both sides of the planetary rollers 2 (in this embodiment, there is only one set of planetary rollers), the loading rollers 3 on one side are used for forward transmission, and the loading rollers 3 on the other side are used for reverse transmission, forming forward and reverse loading transmission.

[0043] In this embodiment, the planet carrier 5 and the outer ring 4 are coaxially rotated together. The loading roller 3 is set on the planet carrier through the loading roller shaft and transmits power to the planet carrier 5, thereby driving the planet carrier to rotate in the selected transmission direction. That is, the loading roller shaft is floatingly set on the planet carrier and drives the planet carrier in the transmission direction.

[0044] As shown in the figure, the planetary carrier 5 is rotatably engaged with the outer ring 4 via the bearing 16, and the outer ring is fixed on the driver housing 10.

[0045] This invention can be used for both speed reduction and speed increase transmissions, and can also form a differential transmission in a power system. These rotational states can be used in mechanical transmission systems, wherein:

[0046] The outer ring 4 remains stationary while the sun gear 1 and planet carrier 5 rotate; or the planet carrier 5 remains stationary while the sun gear 1 and outer ring 4 rotate; or the sun gear 1, outer ring 4, and planet carrier 5 all rotate; further details will not be elaborated here.

[0047] When using a power distribution strategy in the design, these rotational states can be coupled with other gear trains or transmissions to have additional sub-states.

[0048] In this embodiment, the planetary carrier 5 is provided with a loading roller groove 6 in the circumferential direction. The loading roller shaft (rotatably engaged with a loading roller shaft 15 mounted on the loading roller shaft; of course, under sufficient self-lubricating conditions, the loading roller shaft can be directly rotated, which will not be elaborated here) is floatingly disposed in the loading roller groove and abuts against the side wall of the loading roller groove in the transmission direction. Thus, the planetary carrier can be driven to rotate in the direction away from the radial distance, thereby driving the planetary carrier to rotate in the selected transmission direction. "Floating" means that it is placed in the loading roller groove without constraint, but abuts against the side wall of the loading roller groove and is used to drive the planetary carrier to rotate. The loading rollers are floating and their spatial positions are determined by contact with the planetary rollers and the outer ring. When subjected to unbalanced or sudden loads, the rollers can automatically adjust until a balance is re-established, achieving smooth operation. This improves the uniformity of force on the moving parts and helps maintain a reliable fit between the sun gear 1, planetary rollers 2, loading rollers 3, and outer ring 4. The rollers are in line contact and their rotation axes are parallel to each other, achieving zero-spin transmission, which greatly improves transmission efficiency and load-bearing capacity. By shaping the edges, stress concentration can be effectively reduced, giving the traction drive enormous transmission potential for high-speed and heavy-load operation.

[0049] In this embodiment, a loading roller groove 6 is provided on the planetary carrier 5 corresponding to the radial distance. Two loading rollers 3 on both sides of the same radial distance are respectively provided at both ends of the loading roller groove 6 in the circumferential direction. The initial preload of the loading roller 3 is applied to the loading roller bearing 15 by the side wall of the loading roller groove 6. The side wall of the loading roller groove 6 refers to the two side walls in the circumferential direction, which will not be described in detail here.

[0050] In this embodiment, the initial preload is applied by elastic elements or elastic layers provided on the two circumferential side walls of the loading roller groove 6 (applying pressure directly to the loading roller bearing, thus acting on the loading roller); such as Figure 7 As shown, this embodiment is an elastic layer, which can be made of an elastic material such as hard rubber. The adjustment is mainly achieved by adjusting the interference fit through thickness.

[0051] Alternatively, the following structure can be used to apply the initial preload:

[0052] The planetary carrier is provided with a loading groove adjacent to the loading roller groove, and the two side walls of the loading groove are adjacent to the two side walls of the loading roller groove; the pressure toward the radial distance is formed by applying pressure to the side walls of the loading roller groove within the loading groove, causing elastic deformation of the side walls of the loading roller groove; the elastic deformation of the side walls of the loading roller groove is formed by the bidirectional bolt pair 19 within the loading groove, such as... Figure 9As shown, two screws with different directions of rotation are fixed to the two side walls of the loading groove on the planetary carrier 5, and the other end is threaded with a nut. By rotating the nut, the two screws with different directions of rotation move to the sides, thereby causing the side wall of the loading roller groove to undergo elastic deformation to form an initial preload.

[0053] Alternatively, it can be formed by a pressure spring or tension spring 18 within the loading groove, such as... Figure 8 As shown, if a tension spring is used, pressure needs to be formed on the side wall of the loading roller groove in the initial state, and the tension spring is used to apply tension for adjustment; a compression spring applies pressure by pressing the two ends of the loading groove to deform the two sides of the loading roller groove, which will not be elaborated here.

[0054] The bearing 15 of the loading roller shaft of the loading roller 3 contacts the inner wall of the loading roller groove 6. The loading roller groove 6 applies pressure to the loading roller by applying pressure to the bearing 15, thus constraining the loading roller 3 to rotate freely in the wedge-shaped space composed of the outermost planetary roller and the outer ring 4. During operation, the contact force between the bearing 15 and the inner wall of the groove 6 forces the loading roller 3 into the wedge-shaped space, wedging and squeezing each stage of rollers, so that the normal load is proportional to the transmitted torque, thereby generating the desired tangential force to transmit power, effectively preventing slippage, and improving the transmission efficiency and service life of the planetary traction drive.

[0055] In this embodiment, the planetary carrier includes a left end plate 5a and a right end plate 5b. The left end plate 5a and the right end plate 5b are respectively provided with loading roller grooves 6. The two ends of the loading roller shaft are respectively rotatably disposed in the loading roller grooves 6 of the left end plate 5a and the right end plate 5b through bearings. The planetary roller 3 is floating between the left end plate and the right end plate.

[0056] like Figure 2 , 3 As shown, the planetary carrier 5 is fixed with end caps 9 (left end cap and right end cap, indicated by the same mark) and baffles 8 (left baffle and right baffle, indicated by the same mark) on both sides for axial limiting; the limiting method is to open limiting holes or limiting grooves for the shaft to pass through (the shaft needs to be provided with corresponding shaft shoulders), which will not be described in detail here.

[0057] In this embodiment, the loading roller groove 6 is disposed on the outer circumference of the left and right end plates, such as... Figure 4 As shown; or, the left and right end disks are annular structures, and the loading roller groove is located within the inner circle of the annular structure, as shown. Figure 5 As shown; or, the left and right end plates are each composed of separate components, and the loading roller groove is formed between adjacent separate components. Of course, the separate components need to be fixedly installed (e.g., installed on the corresponding end caps) and form a complete planetary carrier structure, such as... Figure 6 As shown; all the above structures can achieve the purpose of the invention, and will not be described in detail here.

[0058] In this embodiment, the sun gear 1 and the outer ring 4 are coaxial;

[0059] Or, such as Figure 11 As shown, the sun gear and the outer ring are eccentrically arranged, and the diameters of the planetary rollers are different to accommodate the eccentric structure between the sun gear and the outer ring, which will not be elaborated further here.

[0060] In this embodiment, the planetary rollers are a single-layer planetary roller structure arranged along the circumference.

[0061] Or, such as Figure 10 As shown, the planetary rollers are arranged in multiple sets to form a multi-layered planetary roller structure along the radial direction. The planetary rollers in different sets form rolling contact in the radial direction. The loading roller is located between the outermost planetary roller set and the outer ring, that is, between the planetary rollers of the outermost planetary roller set and the outer ring as shown in the figure, which will not be described in detail here. The arrangement of multiple sets of planetary rollers is beneficial for fitting the transmission ratio as needed and for improving the load capacity.

[0062] Or, such as Figure 12 As shown, Figure 12 An exploded view of a stepped planetary roller structure with multiple sets of mating components is provided (the outer ring is omitted, and the sun gear and loading roller are labeled using the same reference numerals as before). The planetary rollers can be axially stepped and consist of multiple sets, arranged to form a radially multi-layered planetary roller structure. The minor and major diameters of different sets of planetary rollers form rolling contact radially. The loading roller is located between the outermost planetary roller set and the outer ring. In this stepped structure, the planetary rollers of different sets can mutually limit each other axially. As shown in the figure, this embodiment has two sets of planetary rollers, planetary roller 2a and planetary roller 2b, where planetary roller 2b rolls in contact with the sun gear, and planetary roller 2a rolls in contact with the loading roller. The planetary rollers 3 and 2a are in rolling contact. The planetary roller 2b has an annular groove structure with a central annular depression, while the planetary roller 2a has an annular protrusion in the middle and annular necks at both ends. The annular protrusion makes rolling contact with the annular groove of the planetary roller 2b, and the annular necks at both ends make rolling contact with the groove edge of the annular groove of the planetary roller 2b. The planetary rollers with stepped shaft structures of different diameters cooperate with each other. After rolling cooperation with different diameters, sliding friction may occur, but the mutual support makes the structure more stable. The cooperation structure of groove and protrusion can ensure the stability of the axial structure and the compactness of the radial structure, thereby increasing the load capacity and achieving the effect of increasing the transmission ratio. It has good flexibility in installation and use.

[0063] like Figure 2, Figure 3 As shown, the sun gear 1 is mounted in the mounting holes of the two end caps 9 (including the left and right end caps, denoted by the same mark) via bearings 14, and rotates around its own axis. A sealing ring is provided between the sun gear 1 and the mounting holes of the end caps 9, with an appropriate gap. The planetary carrier 5 and the two end caps 9 are fastened together by bolts. The planetary carrier 5 is mounted on the drive housing 10 via bearings 16 with sealing rings to improve sealing performance. The inner surface of the outer ring 4 is designed with an oil groove to store oil, improve contact, and adjust the effective contact length with the loading roller 3. The outer ring 4 is fixed to the inner wall of the housing 10. The housing 10 is provided with an oil groove 13, and the housing 10 has an oil inlet 11 and an oil outlet 12. This is a conventional mechanical structure and will not be described in detail here.

[0064] This planetary traction drive is a miniaturized, high-speed, lightweight, and integrated drive solution with advantages such as high speed ratio, high rigidity, high efficiency, zero spin, high load capacity, and high-precision transmission. It is suitable for high-speed power transmission, especially in the electric vehicle field. Thanks to the high-speed and smooth performance of the traction drive, a high-speed motor can be used to reduce motor size and increase system power density, thereby achieving miniaturized electrical design. Furthermore, this drive does not require complex specialized machining equipment; the simple shapes of the parts and their self-centering properties make it insensitive to installation errors, resulting in good manufacturability, low cost, high product consistency, and relatively simple engineering implementation, facilitating mass production on assembly lines.

[0065] 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 loading-type planetary traction drive, characterized in that: It includes a sun gear, an outer ring, a planet carrier, and planetary rollers evenly distributed circumferentially between the sun gear and the outer ring; the planetary rollers are in rolling contact with the sun gear and have a radial distance between them and the outer ring, thereby forming a wedge-shaped loading space on both sides of the radial distance circumferential direction between the planetary rollers and the outer ring. It also includes a loading mechanism, which includes a loading roller located within a wedge-shaped loading space and in rolling contact with the planetary roller and the outer ring, the loading roller being provided with an initial preload toward the radial pitch; Both the planetary rollers and the loading rollers are floating, and the loading rollers transmit power to the planet carrier. The planetary carrier rotates coaxially with the outer ring, and the loading roller is mounted on the planetary carrier via the loading roller shaft and transmits power to the planetary carrier. The planetary carrier is provided with a loading roller groove in the circumferential direction. The loading roller shaft is floatingly disposed in the loading roller groove and abuts against the side wall of the loading roller groove in the transmission direction, thereby transmitting power to the planetary carrier in a direction away from the radial distance. The planetary carrier includes a left end plate and a right end plate. The left end plate and the right end plate are respectively provided with loading roller grooves. The two ends of the loading roller shaft are respectively floatingly disposed in the loading roller grooves of the left end plate and the right end plate, so that the planetary rollers are floating between the left end plate and the right end plate.

2. The loading-type planetary traction drive according to claim 1, characterized in that: The loading rollers are provided in the loading spaces on both sides of the radial spacing, and the initial preload is provided in each of them.

3. The loading-type planetary traction drive according to claim 1, characterized in that: The loading roller groove is set on the planetary carrier corresponding to the radial spacing, and the two loading rollers on both sides of the same radial spacing are set at both ends of the circumferential direction of the loading roller groove. The initial preload of the loading roller is applied to the loading roller shaft by the side wall of the loading roller groove.

4. The loading-type planetary traction drive according to claim 3, characterized in that: The initial preload is applied by an elastic element or elastic layer provided on the side wall of the loading roller groove; Alternatively, a loading groove is provided on the planetary carrier adjacent to the loading roller groove, and the sidewall of the loading groove is adjacent to the sidewall of the loading roller groove; the initial preload is formed by applying pressure to the sidewall of the loading roller groove within the loading groove, causing elastic deformation of the sidewall of the loading roller groove; the elastic deformation of the sidewall of the loading roller groove is formed by a bidirectional bolt pair within the loading groove, or by a pressure spring within the loading groove.

5. The loading-type planetary traction drive according to claim 4, characterized in that: The loading roller groove is disposed on the outer circle of the left and right end plates; or, the left and right end plates are annular structures, and the loading roller groove is located on the inner circle of the annular structure; or, the left and right end plates are each composed of separate components, and the loading roller groove is formed between adjacent separate components.

6. The loading-type planetary traction drive according to claim 1, characterized in that: The sun gear is coaxial with the outer ring; Alternatively, the sun gear and the outer ring are eccentrically positioned, and the diameters of the planetary rollers differ to accommodate the eccentric structure between the sun gear and the outer ring.

7. The loading-type planetary traction drive according to claim 1, characterized in that: The planetary rollers are a single-layer planetary roller structure arranged along the circumference. Alternatively, the planetary rollers are in multiple sets, and the multiple sets of planetary rollers are arranged to form a multi-layered planetary roller structure along the radial direction. Rolling contact is formed between different sets of planetary rollers, and the loading roller is located between the outermost set of planetary rollers and the outer ring. Alternatively, the planetary rollers may have an axial stepped structure and be in multiple groups. The multiple groups of planetary rollers are arranged to form a radial multi-layer planetary roller structure. The minor and major diameters of the planetary rollers in different groups form a rolling contact in the radial direction. The loading roller is located between the planetary rollers of the outermost planetary roller group and the outer ring.

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