A dual-ratio direct-drive differential

Abstract

The application discloses a double-speed-ratio direct-drive differential, and belongs to the technical field of differentials. The differential comprises an input shaft one, an input shaft two, a bearing seat one, a primary-secondary transmission assembly, a tertiary transmission assembly, a bearing seat two, a tertiary frame and a belt pulley. The input shaft one is sleeved in the input shaft two, and the primary-secondary transmission assembly is composed of a primary transmission assembly and a secondary transmission assembly which share a same primary-secondary frame. When the input shaft one is connected with a motor and the input shaft two is fixed and does not rotate, power is transmitted to the tertiary transmission assembly through the secondary transmission assembly to realize a first speed ratio; when the input shaft one is fixed and does not rotate and the input shaft two is connected with the motor, power is transmitted to the secondary transmission assembly and the tertiary transmission assembly through the primary transmission assembly to realize a second speed ratio. The double-speed-ratio direct-drive differential realizes double-speed-ratio output through double input shafts and transmission path switching, guarantees transmission precision and meets the use requirements of the differential under various working conditions.

Description

Technical Field

[0001] This invention belongs to the field of differential technology, specifically relating to a dual-ratio direct-drive differential. Background Technology

[0002] A centrifuge is a mechanical device that uses centrifugal force to achieve solid-liquid or liquid-liquid separation, and is widely used in chemical, pharmaceutical, food, and environmental protection industries. The core components of a centrifuge include the drum and rotor, which have a certain speed difference, provided by a differential gear. The performance of the differential gear directly affects the separation efficiency and energy consumption of the centrifuge.

[0003] Currently, the differential gears in commonly used centrifuges typically have only one fixed speed ratio. When separating different media, the only way to achieve different speed differences is by adjusting the speeds of the two input motors. Although this speed control scheme can meet the requirements to a certain extent, the operating efficiency of the motors varies at different speeds. When effective separation of certain specific media is required, the two input motors often cannot operate in their respective high-efficiency ranges simultaneously, resulting in high overall energy consumption.

[0004] Furthermore, existing differentials typically employ a split design for their planetary transmission mechanisms, with the first-stage and second-stage planetary carriers manufactured separately before assembly. This structure not only increases the number of parts and assembly steps but also makes them prone to accumulating assembly errors, affecting transmission accuracy. In terms of lubrication, existing differentials have relatively simple lubrication circuit designs, making it difficult to ensure adequate lubrication of the bearings and gear meshing surfaces under high-speed rotation conditions, thus impacting the differential's lifespan. Regarding sealing, the input shaft seal structure of existing differentials is prone to wear after prolonged use, resulting in high replacement costs.

[0005] Therefore, it is necessary to design a new type of differential with multiple speed ratio options, compact structure, reliable lubrication, and low maintenance cost to meet the usage requirements of centrifuges under different operating conditions, while improving the operating efficiency of the motor and achieving energy saving and consumption reduction. Summary of the Invention

[0006] To address the problems existing in the background art, the present invention provides a dual-speed ratio direct-drive differential, comprising an input shaft one, an input shaft two, a bearing housing one, a first and second stage transmission assembly, a third stage transmission assembly, a bearing housing two, a third stage frame, and a pulley; Input shaft one is fitted into input shaft two. A secondary center wheel is fixedly connected to the right end of input shaft one, and a gear is provided at the right end of input shaft two. The primary and secondary transmission assembly consists of a primary transmission assembly and a secondary transmission assembly, which share the same primary and secondary frame. The primary transmission assembly includes a primary gear, a primary bearing, a primary wheel post, and a primary gear ring. The primary gear ring is fixedly connected to the bearing housing by screws. The gear at the right end of the input shaft meshes externally with the primary gear, and the primary gear meshes internally with the primary gear ring. The secondary transmission assembly includes a secondary gear, a secondary bearing, a secondary wheel post, and a secondary gear ring. The secondary center gear meshes externally with the secondary gear, and the secondary gear meshes internally with the secondary gear ring. The three-stage transmission assembly includes the external toothed part of the second-stage gear ring, the third-stage wheel, the third-stage gear ring, the sliding bearing, the third-stage wheel column, the left support of the third-stage frame, and the right support of the third-stage frame. The external toothed part of the second-stage gear ring meshes with the third-stage wheel for external transmission, and the third-stage wheel meshes with the third-stage gear ring for internal transmission. When input shaft one is connected to the motor and rotates, and input shaft two is fixed and the pulley rotates, the power is transmitted through input shaft one to the secondary transmission assembly and then to the tertiary transmission assembly, achieving the first speed ratio. When input shaft one is fixed and the motor connected to input shaft two rotates and the pulley rotates, the power is transmitted through input shaft two to the primary transmission assembly and then to the secondary and tertiary transmission assemblies, achieving the second speed ratio.

[0007] In a preferred embodiment, the primary and secondary frames are designed as a single unit, comprising a primary wheel seat cavity, a lower mounting hole on the primary wheel post, an upper mounting hole on the primary wheel post, a primary pin hole, a secondary wheel seat cavity, a lower mounting hole on the secondary wheel post, an upper mounting hole on the secondary wheel post, a secondary pin hole, an upper support plate on the primary and secondary frames, and a lower support plate on the primary and secondary frames. The primary and secondary wheel seat cavities are evenly offset in the circumferential direction, and the upper and lower support plates on the primary and secondary frames are evenly offset from the primary and secondary wheel seat cavities, respectively. The distances from the lower and upper mounting holes on the primary wheel post to the center of the primary and secondary frames are independently set, as are the distances from the lower and upper mounting holes on the secondary wheel post to the center of the primary and secondary frames. The number of primary and secondary wheel seat cavities is equal.

[0008] In a preferred embodiment, input shaft one is fixed to input shaft two via bearing one and input shaft bearing two, and input shaft two is fixed to bearing seat one via bearing two and bearing three. The input shaft bearing is installed in input shaft two and is axially positioned by the step on the left side of input shaft two and the spacer on the right side of the input shaft bearing. The spacer is axially fixed by shaft clamp five. Input shaft one is provided with through oil holes one and two, and input shaft two is provided with through oil holes three and four for lubricating bearing one and input shaft bearing two. Input shaft one is axially fixed by shaft clamp one, input shaft two is axially fixed by shaft clamp two, and bearing three is axially fixed by shaft clamp three. It also includes a wear-resistant sleeve, an O-ring, oil seal one, oil seal two, sealing seat one, and sealing seat two. The wear-resistant sleeve is interference-fitted onto input shaft two with an O-ring. Oil seal one is installed on sealing seat one, and oil seal two is installed on sealing seat two and forms a rotary seal with the wear-resistant sleeve.

[0009] In a preferred embodiment, the first-stage wheel has several oil passage holes 5 at its tooth root and oil passage grooves on both end faces; the second-stage wheel has several oil passage holes 15 at its tooth root and oil passage grooves on both end faces; the first-stage wheel post has an oil passage hole 9 and several oil passage holes 10; the first and second stage frames have an oil passage hole 7, with oil passage hole 9 axially connected to oil passage hole 7; the second-stage wheel post has an oil passage hole 13 and several oil passage holes 14; the first and second stage frames also have an oil passage hole 8, with oil passage hole 13 axially connected to oil passage hole 8; each of the left and right end faces of the first-stage wheel and the first-stage bearing has a first-stage bearing retaining ring, and each of the left and right end faces of the second-stage wheel and the second-stage bearing has a second-stage bearing retaining ring; the first-stage wheel post is fixed to the first and second stage frames axially and circumferentially by inserting a first-stage pin into a first-stage pin hole, and the second-stage wheel post is fixed to the first and second stage frames axially and circumferentially by inserting a second-stage pin into a second-stage pin hole.

[0010] In a preferred embodiment, the left end face step of the first and second stage frames is axially positioned by the outer ring of bearing four, and the right end face step is axially positioned by the inner ring of bearing seven. Bearing four is disposed in the seat cavity of bearing housing one, and bearing housing one has several oil passage holes six on the left end face of bearing four. The left end of the inner hole of the second stage center wheel is interference-fitted with the left side of the right end of the input shaft one, and the right end is connected to the right side of the right end of the input shaft one through a spline transition fit, and is axially fixed by shaft clamp six. The second stage gear ring includes an internal gear part and an external gear part. The internal gear part is radially positioned with bearing housing one through bearing six, and bearing six is ​​axially fixed by a hole clamp. The right end face of the external gear part is radially positioned with the output end of the third stage frame through bearing eight. An oil passage hole twelve is provided at the center of the external gear part, and an oil passage hole eleven is provided on the left side of the external gear part.

[0011] In a preferred embodiment, the outer circumference of the sliding bearing is provided with N intersecting spiral oil grooves. Oil groove one and oil groove four form a complete spiral annular oil groove, and oil groove three and oil groove two form a complete spiral annular oil groove. The two sets of oil grooves intersect at the midpoint and both ends of the width of the sliding bearing, forming an outer combined oil channel that allows oil to flow between them. The inner hole of the sliding bearing is provided with N intersecting spiral oil grooves. Oil groove five and oil groove eight form a complete spiral annular oil groove, and oil groove six and oil groove seven form a complete spiral annular oil groove. The two sets of oil grooves intersect at the midpoint and both ends of the width of the sliding bearing, forming an inner combined oil channel that allows oil to flow between them. The inner hole and outer circumference of the sliding bearing are respectively in clearance rotational fit with the outer circumference of the third-stage wheel column and the inner hole of the third-stage wheel, and the clearance between the inner hole of the sliding bearing and the outer circumference of the third-stage wheel column is greater than the clearance between the outer circumference of the sliding bearing and the inner hole of the third-stage wheel.

[0012] In a preferred embodiment, the third-stage wheel column is provided with a third-stage wheel column notch, a third-stage wheel column oil passage surface, a third-stage wheel column bearing outer circle, an oil passage hole seventeen penetrating the third-stage wheel column oil passage surface, and an oil passage hole sixteen penetrating the width direction of the third-stage wheel column; the third-stage wheel column oil passage surface is located in the middle of the width of the third-stage wheel column bearing outer circle and does not communicate with the two end faces; the third-stage frame left support is provided with a third-stage wheel column left hole, and the third-stage frame right support is provided with a third-stage wheel column right hole and a third-stage wheel column notch hole; the two ends of the third-stage wheel column respectively mate with the third-stage wheel column left hole and the third-stage wheel column right hole, and the third-stage wheel column notch mates with the third-stage wheel column notch hole to prevent the third-stage wheel column from rotating.

[0013] In a preferred embodiment, a locating pin and a screw are also included. The locating pin has a notch, the left support of the third-level frame has a notch hole and a left hole, and the right support of the third-level frame has a right hole. The notch of the locating pin is installed corresponding to the notch of the notch hole and passes through the left hole and the right hole in sequence. The screw passes through the right hole of the locating pin of the right support of the third-level frame and is threadedly fastened to the locating pin, so that the left support and the right support of the third-level frame form a rigid connection.

[0014] In a preferred embodiment, the outer circumference of the three-stage gear ring is provided with N heat dissipation grooves; the output end of the three-stage frame is fixed on the bearing seat two by two parallel bearings five, and is axially fixed by the shaft clamp four; the bearing seat two is connected to the centrifuge drum, and the three-stage frame is connected to the centrifuge rotor; it also includes a sealing seat three and an oil seal three, the oil seal three is installed on the sealing seat three to seal the output end of the differential.

[0015] In a preferred embodiment, when the input shaft one and input shaft two rotate in the same direction and the pulley rotates, the output speed of the secondary gear ring is lower than the speed under the first speed ratio and the second speed ratio, thus achieving low speed difference output; when the input shaft one and input shaft two rotate in opposite directions and the pulley rotates, the output speed of the secondary gear ring is higher than the speed under the first speed ratio and the second speed ratio, thus achieving high speed difference output.

[0016] The beneficial effects achieved by this invention are as follows: First, this invention features two independent power input ends, input shaft one and input shaft two, arranged coaxially and nested. This, combined with the switching of transmission paths in the first and second stage transmission assemblies and the third stage transmission assemblies, achieves dual-speed ratio output of the differential. When input shaft one is connected to a rotating motor, and input shaft two is fixed with its pulley rotating, power is transmitted through the second stage transmission assembly to the third stage transmission assembly to achieve the first speed ratio. When input shaft one is fixed with its rotating motor and input shaft two is connected to a rotating pulley, power is transmitted through the first stage transmission assembly to both the second and third stage transmission assemblies to achieve the second speed ratio. Operators can select an appropriate speed ratio based on the characteristics of the material being separated, allowing the motor to operate in a higher efficiency range, thereby reducing overall energy consumption. When input shaft one and input shaft two rotate in the same direction, the output speed difference is lower than the speed difference when using only the first or second speed ratio; when input shaft one and input shaft two rotate in opposite directions, the output speed difference is higher than the speed difference when using only the first or second speed ratio. By adjusting the speed and direction of the two input shafts, a continuously adjustable speed difference output can be achieved while the motor is working at high efficiency, meeting the separation needs under more working conditions.

[0017] Secondly, the first and second stage planetary carriers of this invention adopt an integrated design, combining the planetary carriers of the first and second stage transmission assemblies into a single integral part. The first and second stage wheel seat cavities are evenly offset in the circumferential direction, and the distances from the first stage wheel post mounting holes to the centers of the first and second stage carriers are independently set. This integrated design reduces the number of parts and assembly steps, avoiding coaxiality deviations caused by accumulated assembly errors in split structures, and ensuring the phase relationship between the two stages of planetary transmission. The offset distribution of the first and second stage wheel seat cavities makes the stress on the first and second stage carriers more uniform, while also reducing the manufacturing difficulty. The pitch circle diameters of the first and second stage planetary transmissions can be determined separately according to their respective transmission ratio requirements, without being constrained by the other, thus improving the flexibility of transmission ratio design.

[0018] Third, this invention incorporates through-hole lubricating oil into key components such as the input shaft, primary gear column, secondary gear column, tertiary gear column, secondary gear ring, and bearing housing. Interlocking spiral oil grooves are machined on the inner and outer diameters of the sliding bearing, forming a complete lubrication system. The spiral oil groove design ensures a continuous oil film on the inner and outer surfaces of the sliding bearing. Regardless of the rotation direction of the sliding bearing relative to the tertiary gear column and gear, the spiral oil grooves guide the lubricating oil to the entire working surface, preventing localized dry friction. The notch on the tertiary gear column mates with the notched hole on the right support of the tertiary frame, preventing rotation of the tertiary gear column and ensuring the stability of the lubricating oil outlet position, allowing lubricating oil to continuously enter the oil grooves of the sliding bearing. The heat dissipation grooves on the outer diameter of the tertiary gear ring increase the heat dissipation area, accelerating heat transfer to the surrounding air and helping to reduce the operating temperature of the tertiary transmission assembly.

[0019] Fourth, this invention features an interference fit of a wear-resistant sleeve on the second input shaft, with an O-ring placed between the wear-resistant sleeve and the second input shaft. The second oil seal and the wear-resistant sleeve form a rotary seal. The O-ring prevents relative sliding between the wear-resistant sleeve and the second input shaft, and also serves as an auxiliary seal. The wear-resistant sleeve can be made of a material with better wear resistance; once it wears to a certain extent, only the wear-resistant sleeve needs to be replaced, eliminating the need to replace the entire second input shaft, thus reducing maintenance costs. The notch on the locating pin mates with the notch hole on the left support of the third-stage carrier to prevent rotation. The locating pin passes sequentially through the left and right supports of the third-stage carrier and is secured with screws, forming a rigid connection between the left and right supports. Together, they bear the torque and radial force generated by the three-stage planetary transmission, improving the overall rigidity and load-bearing capacity of the three-stage planetary carrier. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the dual-speed ratio direct-drive differential in this invention patent.

[0021] Figure 2 This is a schematic diagram of the structure of the first and second stage transmission assembly I in this invention patent.

[0022] Figure 3 This is a schematic diagram of the three-stage transmission assembly II in this invention patent.

[0023] Figure 4 This is a schematic diagram of the sliding bearing in this invention patent.

[0024] Figure 5 This is a schematic diagram of the first and second stage planetary carrier in this invention patent.

[0025] Figure 6 This is a schematic diagram of the three-stage wheel column structure in this invention patent.

[0026] Figure 7 This is a schematic diagram of the right support structure of the three-stage frame in this invention patent.

[0027] Figure 8 This is a schematic diagram of the positioning pin in this invention patent.

[0028] Figure 9 This is a schematic diagram of the left support of the three-stage frame in this invention patent.

[0029] In the diagram: I. First and second stage transmission assembly; II. Third stage transmission assembly; III. First stage transmission assembly; IV. Second stage transmission assembly; 1. Input shaft 1; 2. Seat 1; 3. Oil seal 1; 4. Shaft clip 1; 5. Bearing 1; 6. Input shaft 2; 7. Wear-resistant sleeve; 8. O-ring; 9. Oil seal 2; 10. Seat 2; 11. Bearing 2; 12. Shaft clip 2; 13. Bearing housing 1; 14. Bearing 3; 15. Shaft clip 3; 16. Bearing 4; 17. Pulley; 18. Third stage frame; 18a. Output shaft; 18b. Right support of third stage frame; 18c. Right hole of third stage wheel post; 18d. Notched hole of third stage wheel post; 18e. Right hole of locating pin; 19. Bearing 5 20. Bearing housing II; 21. Shaft clip IV; 22. Sealing seat III; 23. Oil seal III; 24. Primary gear ring; 25. Primary and secondary frame; 25a. Mounting hole on secondary wheel post; 25b. Secondary pin hole; 25c. Secondary wheel seat cavity; 25d. Lower support plate of primary and secondary frame; 25e. Lower mounting hole on secondary wheel post; 25f. Mounting hole on primary wheel post; 25g. Lower mounting hole on primary wheel post; 25h. Primary pin hole; 25i. Primary wheel seat cavity; 25j. Upper support plate of primary and secondary frame; 26. Input shaft bearing; 27. Shaft clip V; 28. Spacer; 29. ​​Primary wheel; 30. Primary bearing retaining ring; 31. Primary wheel post; 32. Primary bearing; 33. Primary pin 34. Hole clamp; 35. Bearing 6; 36. Secondary gear ring; 36a. Internal gear part; 36c. External gear part; 37. Bearing 7; 38. Secondary center gear; 39. Shaft clamp 6; 40. Secondary wheel post; 41. Secondary pin; 42. Secondary bearing retaining ring; 43. Secondary bearing; 44. Secondary wheel; 45. Tertiary gear ring; 46. Tertiary wheel; 47. Sliding bearing; 48. Left support of tertiary frame; 48a. Locating pin notched hole; 48b. Locating pin left hole; 48c. Tertiary wheel post left hole; 49. Tertiary wheel post; 49c. Tertiary wheel post notch; 49d. Tertiary wheel post oil passage surface; 50. Locating pin; 50a. Locating pin notched edge; 51. Screw; 52. Bearing 8; 1a, Oil passage hole 1; 1b, Oil passage hole 2; 6a, Oil passage hole 3; 6b, Oil passage hole 4; 29a, Oil passage hole 5; 13a, Oil passage hole 6; 25k, Oil passage hole 7; 25m, Oil passage hole 8; 31a, Oil passage hole 9; 31b, Oil passage hole 10; 36b, Oil passage hole 11; 36d, Oil passage hole 12; 40a, Oil passage hole 13; 40b, Oil passage hole 14; 44a, Oil passage hole 15; 47a, Oil groove 1; 47b, Oil groove 2; 47c, Oil groove 3; 47d, Oil groove 4; 47e, Oil groove 5; 47f, Oil groove 6; 47g, Oil groove 7; 47h, Oil groove 8; 49a, Oil passage hole 16; 49b, Oil passage hole 17. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figures 1 to 9 As shown, this invention provides a dual-ratio direct-drive differential, which can achieve two different transmission ratios by switching different power input paths, thereby enabling the drive motor to operate at a higher efficiency point and achieving energy saving. The direct-drive type directly drives the differential's input shaft through the motor, eliminating the need for a traditional reduction gear mechanism and simplifying the transmission chain.

[0032] The dual-ratio direct-drive differential of the present invention includes an input shaft 1, an input shaft 6, a bearing housing 13, a first and second stage transmission assembly I, a third stage transmission assembly II, a bearing housing 20, a third stage frame 18, and a pulley 17. Input shaft 1 and input shaft 6 form a dual-input structure, each capable of connecting to an independent drive motor. The pulley 17 is mounted on the differential housing and is used to connect a third motor to drive the overall differential housing to rotate. Bearing housing 13 and bearing housing 20 serve as support bases at both ends of the differential, providing a stable mounting reference for the internal transmission mechanism.

[0033] Input shaft 1 is a hollow shaft structure and is fitted into the inner hole of input shaft 6, with the two input shafts arranged coaxially and nested. A secondary center gear 38 is fixedly connected to the right end of input shaft 1, serving as the sun gear of the secondary planetary transmission. An external gear is machined to the right end of input shaft 6, serving as the sun gear of the primary planetary transmission and meshing with the primary gear 29. This coaxial nested dual input shaft structure allows both power inputs to share the same axis, effectively reducing the radial dimension of the differential and avoiding interference between the two input shafts.

[0034] The first and second stage transmission assembly I consists of the first stage transmission assembly III and the second stage transmission assembly IV. The first stage transmission assembly III and the second stage transmission assembly IV share the same first and second stage carrier 25, which adopts an integrated design, combining the two planetary carriers that would otherwise need to be manufactured separately into a single integral part. This integrated first and second stage carrier 25 ensures a compact structure while guaranteeing the coaxiality and phase relationship between the two planetary transmission stages, avoiding the accumulation of assembly errors that might occur with a separate structure.

[0035] The primary transmission assembly III includes an external gear at the right end of input shaft II 6, a primary gear 29, a primary bearing 32, a primary wheel post 31, and a primary gear ring 24. The primary gear 29 consists of planetary gears in the primary planetary transmission, typically numbered in the form of three or four evenly distributed around the circumference. The primary bearing 32 is mounted in the inner bore of the primary gear 29, and the primary wheel post 31 passes through the inner ring of the primary bearing 32 and is fixed to the primary and secondary carriers 25. The primary gear ring 24 is the internal gear ring of the primary planetary transmission, fixedly connected to bearing housing I 13 by screws and rotating synchronously. The external gear at the right end of input shaft II 6 meshes externally with the primary gear 29, while the primary gear meshes internally with the primary gear ring. When input shaft II 6 rotates, the primary gear 29 rotates on its own axis while simultaneously revolving around input shaft II 6; this revolving motion is transmitted to the primary and secondary carriers 25 via the primary wheel post 31.

[0036] The secondary transmission assembly IV includes a secondary center gear 38, a secondary gear 44, a secondary bearing 43, a secondary wheel post 40, and a secondary gear ring 36. The secondary gear 44 is the same number of planetary gears as the primary gear 29. The secondary bearing 43 is installed in the inner bore of the secondary gear 44, and the secondary wheel post 40 passes through the inner ring of the secondary bearing 43 and is fixed to the primary and secondary carriers 25. The secondary center gear 38 meshes with the secondary gear 44. The secondary gear ring 36 includes an internal tooth portion 36a and an external tooth portion 36c. The internal tooth portion 36a meshes internally with the secondary gear 44, and the external tooth portion 36c extends outward and meshes externally with the tertiary gear 46 in the tertiary transmission assembly II. The secondary gear ring 36 serves as both the output component of the secondary planetary transmission and the input component of the tertiary planetary transmission, acting as a link between the two stages.

[0037] The three-stage transmission assembly II includes the external gear portion 36c of the second-stage ring gear 36, the third-stage gear 46, the third-stage ring gear 45, the sliding bearing 47, the third-stage wheel post 49, the left support 48 of the third-stage carrier, and the right support 18b of the third-stage carrier. The third-stage gear 46 is a planet gear of the three-stage planetary transmission, mounted on the third-stage wheel post 49 and supported by the sliding bearing 47. The external gear portion 36c of the second-stage ring gear 36 meshes externally with the third-stage gear 46, while the third-stage gear 46 meshes internally with the third-stage ring gear 45. The third-stage ring gear 45 is fixed to the differential housing, and rotates synchronously with the pulley 17. The left support 48 and the right support 18b of the third-stage carrier together constitute the third-stage planetary carrier, with the right support 18b and the third-stage carrier 18 being an integral structure. The output end 18a of the three-stage frame 18 is fixed on the bearing housing 20 via bearing 5 19. The output end 18a is connected to the centrifuge rotor and transmits the output power of the differential to the rotor.

[0038] When the motor connected to input shaft 1 rotates, and input shaft 2 (6) remains stationary while pulley (17) rotates, power is input from input shaft 1 and transmitted to secondary gear 44 via secondary center wheel 38. Secondary gear 44 rotates on its own axis, driving secondary gear ring 36 to rotate, and its revolution motion is transmitted to primary and secondary frame 25. Since input shaft 2 (6) remains stationary, the rotation of primary and secondary frame 25 drives primary gear 29 to revolve around input shaft 2 (6). During its revolution, primary gear 29 meshes with primary gear ring 24 and rotates. The external teeth 36c of secondary gear ring 36 transmit power to tertiary gear 46, and the revolution motion of tertiary gear 46 is ultimately transmitted to tertiary frame 18 and output from output end 18a. This transmission path achieves the first speed ratio.

[0039] When input shaft 1 is fixed and does not rotate, and input shaft 2 (6) is connected to the motor and the pulley (17) rotates, power is input from input shaft 2 (6) and transmitted to the first-stage wheel 29 via the external gear at the right end of input shaft 2 (6). The first-stage wheel 29 rotates on its own axis and drives the first and second stage frames 25 to revolve. The revolve of the first and second stage frames 25 drives the second-stage wheel 44 to revolve around the fixed second-stage center wheel 38. During the revolve, the second-stage wheel 44 meshes with the second-stage center wheel 38 and rotates on its own axis. The rotational motion is transmitted to the second-stage gear ring 36, causing it to rotate. The second-stage gear ring 36 then transmits the power to the third-stage frame 18 via the third-stage transmission assembly II. This transmission path achieves the second speed ratio. Since the two transmission paths pass through different gear stages, the values ​​of the first speed ratio and the second speed ratio are different. The operator can select the appropriate speed ratio according to the characteristics of the material being separated, so that the motor works in a higher efficiency range.

[0040] like Figure 5 As shown, the primary and secondary frame 25 is provided with a primary wheel seat cavity 25i, a primary wheel post lower mounting hole 25g, a primary wheel post upper mounting hole 25f, a primary pin hole 25h, a secondary wheel seat cavity 25c, a secondary wheel post lower mounting hole 25e, a secondary wheel post upper mounting hole 25a, a secondary pin hole 25b, a primary and secondary frame upper support plate 25j, and a primary and secondary frame lower support plate 25d. The primary wheel seat cavity 25i is used to accommodate the primary wheel 29 and the primary bearing 32, and the secondary wheel seat cavity 25c is used to accommodate the secondary wheel 44 and the secondary bearing 43. The primary wheel seat cavities 25i and 25c are evenly distributed in a staggered manner in the circumferential direction, that is, the primary wheel 29 and the secondary wheel 44 are arranged alternately rather than overlapping in the circumferential direction. This arrangement makes the stress on the primary and secondary frame 25 more uniform and reduces the manufacturing difficulty of the primary and secondary frame 25. The upper support plate 25j and the lower support plate 25d of the first and second level frames are located on the upper and lower sides of the first and second level frames 25, respectively, providing double-end support for the first-level wheel column 31 and the second-level wheel column 40, thereby improving the rigidity and load-bearing capacity of the wheel columns.

[0041] The lower mounting hole 25g and upper mounting hole 25f of the first-stage planetary gear 31 are used to mount the two ends of the first-stage planetary gear 31, and the lower mounting hole 25e and upper mounting hole 25a of the second-stage planetary gear 40 are used to mount the two ends of the second-stage planetary gear 40. The distances from the mounting holes of the first-stage planetary gear 31 to the centers of the first and second-stage carriers 25 and 25a of the mounting holes of the second-stage planetary gear 31 are set independently, meaning that the pitch circle diameters of the first-stage and second-stage planetary transmissions can be determined separately according to their respective transmission ratio requirements, without being constrained by the other. The number of first-stage gear seat cavities 25i and second-stage gear seat cavities 25c are equal, ensuring that the number of first-stage gears 29 and second-stage gears 44 are the same, which is beneficial for load balance in the two-stage planetary transmission.

[0042] Input shaft 1 is fixed to input shaft 2 6 via bearing 5 and input shaft bearing 26. Bearing 5 is installed in the inner hole at the left end of input shaft 2 6, and input shaft bearing 26 is installed in the inner hole at the right end of input shaft 2 6. The two bearings together support input shaft 1, allowing it to rotate independently relative to input shaft 2 6. Input shaft 2 6 is fixed to bearing housing 13 via bearing 11 and bearing 14. Bearing 11 and bearing 14 are arranged axially at intervals, providing stable radial support for input shaft 2 6. The axial positioning of input shaft bearing 26 is achieved by the stepped surface of the inner hole of input shaft 2 6 on its left side and the spacer 28 on its right side. Shaft clip 5 27 is used to limit the axial displacement of spacer 28, thereby fixing the position of input shaft bearing 26. Input shaft 1 is axially fixed by shaft clip 4, input shaft 2 6 is axially fixed by shaft clip 12, and bearing 14 is axially fixed by shaft clip 15. Each shaft clip is installed in the retaining groove of the corresponding shaft or hole to prevent axial movement of the fixed parts.

[0043] Input shaft 1 is provided with through-holes 1a and 1b, and input shaft 6 is provided with through-holes 6a and 6b. Lubricating oil flows from inside the differential through through-holes 1a and 1b to the working surface of bearing 5, and through through-holes 6a and 6b to the working surface of input shaft bearing 26, providing sufficient lubrication and cooling for both bearings. Under high-speed rotation conditions, the lubrication condition of the bearings directly affects their service life; the through-hole structure ensures unobstructed lubrication.

[0044] The input end of the differential is equipped with a complete sealing system, including a wear-resistant sleeve 7, an O-ring 8, an oil seal 3, an oil seal 9, a sealing seat 2, and a sealing seat 10. The wear-resistant sleeve 7 is interference-fitted onto the input shaft 6, and the O-ring 8 is installed in the annular groove between the wear-resistant sleeve 7 and the input shaft 6. The O-ring 8 prevents relative sliding between the wear-resistant sleeve 7 and the input shaft 6 and also serves as an auxiliary seal. Oil seal 3 is installed on the sealing seat 2 and forms a rotary seal with the input shaft 1, while oil seal 9 is installed on the sealing seat 10 and forms a rotary seal with the wear-resistant sleeve 7. The use of the wear-resistant sleeve 7 extends the service life of the oil seal 9 because the material of the wear-resistant sleeve 7 can be selected with better wear resistance. When it wears to a certain extent, only the wear-resistant sleeve 7 needs to be replaced, without replacing the entire input shaft 6.

[0045] like Figure 2 As shown, the first-stage gear 29 has several oil passage holes 29a at the tooth root, and oil passage grooves are provided on both ends of the first-stage gear 29. The second-stage gear 44 has several oil passage holes 44a at the tooth root, and oil passage grooves are also provided on both ends of the second-stage gear 44. The oil passage holes at the tooth root and the oil passage grooves on the ends form a through lubrication oil passage, allowing lubricating oil to enter from the tooth root and flow out from both ends of the gear, lubricating and cooling the first-stage bearing 32 and the second-stage bearing 43 installed in the first-stage gear 29 and the second-stage gear 44. The first-stage wheel column 31 has oil passage holes 31a and several oil passage holes 31b, and the first and second-stage frame 25 has oil passage holes 25k. The oil passage holes 31a and 25k are axially connected, allowing lubricating oil to enter the first-stage wheel column 31 from the first and second-stage frame 25 and flow out through the oil passage holes 31b to the working surface of the first-stage bearing 32, lubricating and cooling the first-stage bearing 32. The secondary wheel column 40 is provided with an oil passage hole 13 40a and several oil passage holes 14 40b. The primary and secondary frame 25 is also provided with an oil passage hole 8 25m. The oil passage hole 13 40a and the oil passage hole 8 25m are axially connected to provide a lubrication passage for the secondary bearing 43.

[0046] Each of the left and right end faces of the primary gear 29 and the primary bearing 32 is provided with a primary bearing retaining ring 30, and each of the left and right end faces of the secondary gear 44 and the secondary bearing 43 is provided with a secondary bearing retaining ring 42. The function of the bearing retaining rings is to limit the axial displacement of the bearings and gears, and at the same time prevent excessive leakage of lubricating oil from the bearing end faces. The primary gear post 31 is fixed to the primary and secondary carriers 25 axially and circumferentially by inserting a primary pin 33 into a primary pin hole 25h, and the secondary gear post 40 is fixed to the primary and secondary carriers 25 axially and circumferentially by inserting a secondary pin 41 into a secondary pin hole 25b. The pin connection method ensures reliable fixation between the gear post and the planetary carrier, and also facilitates disassembly and maintenance.

[0047] The left end face step of the first and second stage gear 25 is axially positioned by the outer ring of bearing 4 16, and the right end face step is axially positioned by the inner ring of bearing 7 37. Bearing 4 16 is housed in the bearing housing 13, supporting the left end of the first and second stage gear 25 so that it can rotate relative to bearing housing 13. Bearing housing 13 has several oil passage holes 6 13a on the left end face of bearing 4 16, through which lubricating oil flows from inside the differential to the working surface of bearing 4 16. Bearing 7 37 is installed between the second stage gear ring 36 and the first and second stage gear 25, supporting the right end of the first and second stage gear 25. With the support of the bearings at both ends, the first and second stage gear 25 can rotate stably around the differential axis.

[0048] The left end of the inner hole of the secondary center wheel 38 is interference-fitted with the left side of the right end of the input shaft 1, while the right end is connected to the right side of the right end of the input shaft 1 via a spline transition fit and is axially fixed by the shaft retainer 39. The interference fit ensures the coaxiality between the secondary center wheel 38 and the input shaft 1, while the spline connection transmits torque. The combination of these two fit methods balances centering accuracy and torque transmission capability. The internal gear portion 36a of the secondary gear ring 36 is radially positioned to the bearing housing 13 via the bearing 35, which is axially fixed by the retainer 34. The right end face of the external gear portion 36c is radially positioned to the output end 18a of the stage 18 via the bearing 52. The bearings 35 and 52 together support the secondary gear ring 36, allowing it to rotate independently relative to the bearing housing 13 and the stage 18. An oil passage hole 12 36d is provided at the center of the external gear part 36c, and an oil passage hole 11 36b is provided on the left side of the external gear part 36c. The lubricating oil flows through the oil passage hole 11 36b and the oil passage hole 12 36d to the meshing area of ​​the three-stage transmission assembly II and the right end of the center hole of the external gear part 36c of the second-stage gear ring, for lubricating the bearing 8 52.

[0049] like Figure 4 As shown, the outer circumference of the sliding bearing 47 is provided with N intersecting spiral oil grooves. Oil groove 1 47a and oil groove 47d form a complete spiral annular oil groove, and oil groove 3 47c and oil groove 2 47b form a complete spiral annular oil groove. The two sets of oil grooves intersect at the midpoint and both ends of the width of the sliding bearing 47, forming an outer combined oil channel that allows oil to flow between them. The inner hole of the sliding bearing 47 is provided with N intersecting spiral oil grooves. Oil groove 5 47e and oil groove 8 47h form a complete spiral annular oil groove, and oil groove 6 47f and oil groove 7 47g form a complete spiral annular oil groove. The two sets of oil grooves intersect at the midpoint and both ends of the width of the sliding bearing 47, forming an inner combined oil channel that allows oil to flow between them. The spiral oil groove design allows the lubricating oil to form a continuous oil film on the inner and outer surfaces of the sliding bearing 47. Regardless of the rotation direction of the sliding bearing 47 relative to the third-stage wheel column 49 and the third-stage wheel 46, the spiral oil groove can guide the lubricating oil to the entire working surface, avoiding local dry friction.

[0050] The inner and outer diameters of the sliding bearing 47 are respectively fitted with the outer diameter of the third-stage wheel post 49 and the inner diameter of the third-stage wheel 46 with clearance. The clearance between the inner diameter of the sliding bearing 47 and the outer diameter of the third-stage wheel post 49 is greater than the clearance between the outer diameter of the sliding bearing 47 and the inner diameter of the third-stage wheel 46. This unequal clearance design makes the rotation of the third-stage wheel 46 relative to the sliding bearing 47 smoother during operation, while the rotation of the sliding bearing 47 relative to the third-stage wheel post 49 needs to overcome slightly greater resistance. This causes the sliding bearing 47 to tend to rotate with the third-stage wheel 46, reducing the wear of the inner diameter of the third-stage wheel 46.

[0051] like Figure 6 and Figure 7 As shown, the third-stage wheel post 49 is provided with a third-stage wheel post notch 49c, a third-stage wheel post oil passage surface 49d, a third-stage wheel post bearing outer circle 49e, an oil passage hole seventeen 49b penetrating the third-stage wheel post oil passage surface 49d, and an oil passage hole sixteen 49a penetrating the width direction of the third-stage wheel post 49. The third-stage wheel post oil passage surface 49d is a flat surface or groove machined on the third-stage wheel post bearing outer circle 49e, located in the middle of the width of the third-stage wheel post bearing outer circle 49e, and not communicating with the two end faces. Lubricating oil enters the interior of the third-stage wheel post 49 through the oil passage hole sixteen 49a, flows out through the oil passage hole seventeen 49b to the third-stage wheel post oil passage surface 49d, and then enters the inner combined oil passage of the sliding bearing 47 to lubricate the sliding bearing 47. Since the third-stage wheel post oil passage surface 49d is not communicating with the end faces, the lubricating oil can only flow through the spiral oil groove of the sliding bearing 47, ensuring the continuity of the oil film.

[0052] like Figure 9 As shown, the left support 48 of the three-stage frame is provided with a left hole 48c for the three-stage wheel column, a notched hole 48a for the locating pin, and a left hole 48b for the locating pin. Figure 7 As shown, the right support 18b of the third-stage frame is provided with a right hole 18c, a notched hole 18d, and a right hole 18e for the locating pin. The two ends of the third-stage wheel 49 mate with the left hole 48c and the right hole 18c, respectively, while the notch 49c mates with the notched hole 18d. The notch 49c is a flat surface machined at one end of the third-stage wheel 49, and the notched hole 18d is a shaped hole that mates with this flat surface. This fit prevents the third-stage wheel 49 from rotating around its own axis. If the third-stage wheel 49 rotates, the outlet position of the oil passage 17 49b will change, potentially preventing lubricating oil from properly entering the oil groove of the sliding bearing 47. Therefore, preventing the rotation of the third-stage wheel 49 is crucial for ensuring the normal operation of the lubrication system.

[0053] like Figure 8As shown, the locating pin 50 has a locating pin notch 50a, which is a flat surface machined from the cylindrical surface of the locating pin 50. The locating pin notch 50a is installed corresponding to the notch of the locating pin notch hole 48a, and passes through the locating pin left hole 48b and the locating pin right hole 18e in sequence. The screw 51 passes through the locating pin right hole 18e of the three-stage carrier 18 and is threadedly fastened to the locating pin 50. The cooperation between the locating pin 50 and the screw 51 forms a rigid connection between the three-stage carrier left support 48 and the three-stage carrier right support 18b, and the two together bear the torque and radial force generated by the three-stage planetary transmission as a whole. The cooperation between the locating pin notch 50a and the locating pin notch hole 48a prevents the rotation of the locating pin 50 and ensures the reliability of the screw 51 connection.

[0054] N heat dissipation grooves are provided on the outer circumference of the third-stage gear ring 45, and the grooves are evenly distributed along the circumference. During operation, the third-stage gear ring 45 rotates at high speed with the differential housing. The heat dissipation grooves increase the surface area of ​​the third-stage gear ring 45, and simultaneously generate airflow turbulence during rotation, accelerating the transfer of heat to the surrounding air, which helps to reduce the operating temperature of the three-stage transmission assembly II. The output end 18a of the third-stage carrier 18 is fixed to the bearing housing 20 by two parallel bearing discs 19. The two bearing discs can withstand greater radial and axial loads, improving the support rigidity of the output end 18a. Shaft clamp 21 is used to axially fix the third-stage carrier 18, preventing it from moving axially. Sealing seat 22 and oil seal 23 are installed on the output side of bearing housing 20. Oil seal 23 forms a rotary seal with the outer circumference of the third-stage carrier 18, preventing leakage of lubricating oil inside the differential. Bearing housing 20 is connected to the centrifuge drum, and the third stage frame 18 is connected to the centrifuge rotor. The speed difference output by the differential is the relative speed between the drum and the rotor.

[0055] The dual-ratio direct-drive differential of the present invention has the following four typical operating conditions during operation.

[0056] Operating condition one involves the rotation of input shaft 1 while input shaft 2 (6) remains stationary, and pulley 17 rotates. Power is supplied from input shaft 1, which drives the secondary center wheel 38 to rotate. The secondary center wheel 38 then drives the secondary wheel 44 to rotate and revolve. The rotation of the secondary wheel 44 drives the secondary gear ring 36 to rotate, and the revolve of the secondary wheel 44 drives the first and second stage supports 25 to rotate. Since input shaft 2 (6) remains stationary, the rotation of the first and second stage supports 25 causes the primary wheel 29 to revolve around input shaft 2 (6). During its revolve, the primary wheel 29 meshes with the primary gear ring 24, causing it to rotate. The primary gear ring 24 experiences the reaction torque transmitted from the primary wheel 29. The external teeth 36c of the secondary gear ring 36 drive the tertiary wheel 46 to rotate and revolve. The rotation of the tertiary wheel 46 drives the tertiary gear ring 45 to rotate, and the revolve of the tertiary wheel 46 causes the left support 48 of the tertiary stage support and the tertiary stage support 18 to rotate synchronously. The third-stage gear ring 45 rotates with the pulley 17. The difference between the rotational speed of the third-stage carrier 18 and the rotational speed of the third-stage gear ring 45 is the output speed difference under operating conditions.

[0057] Operating condition two involves a situation where input shaft 1 remains stationary while input shaft 6 rotates, and pulley 17 also rotates. In this condition, power is input from input shaft 6, and the external gear at the right end of input shaft 6 drives the primary gear 29 to rotate and revolve. The rotation of primary gear 29 causes the primary gear ring 24 to experience a reaction torque, and the revolve of primary gear 29 causes the primary and secondary frames 25 to rotate. The rotation of the primary and secondary frames 25 causes the secondary gear 44 to revolve around the fixed secondary center gear 38. During its revolve, the secondary gear 44 meshes with the secondary center gear 38, generating its own rotation. This rotational motion is transmitted to the secondary gear ring 36, causing it to rotate. The secondary gear ring 36 then drives the tertiary gear 46 to rotate and revolve. The revolve of the tertiary gear 46 causes the left support 48 of the tertiary frame and the tertiary frame 18 to rotate synchronously. The output speed difference in operating condition two differs from that in operating condition one because the power transmission path is different, and the number of gear stages and gear ratios involved in the transmission are different.

[0058] Operating condition three involves input shaft 1 and input shaft 6 rotating in the same direction, with pulley 17 also rotating. In this condition, input shaft 1 drives the secondary center wheel 38 to rotate, which in turn drives the secondary wheel 44 to rotate and revolve. This revolve drives the primary and secondary gear frames 25 to rotate, which in turn drives the primary wheel 29 to rotate around input shaft 6. Since input shaft 6 also rotates in the same direction, the speed of the primary wheel 29 relative to input shaft 6 decreases, consequently reducing the speed of the primary and secondary gear frames 25. This decrease in speed leads to a decrease in the speed of the secondary wheel 44, resulting in a speed of the secondary gear ring 36 lower than in either operating condition one or two. The secondary gear ring 36 is then output from output terminal 18a after a third-stage transmission. In operating condition three, the relative speed difference between the differential housing pulley 17 and output terminal 18a is lower than in operating conditions one and two. The operator can adjust the speeds of input shaft 1 and input shaft 6 to achieve continuous slow-speed output from the third-stage gear frame 18.

[0059] Operating condition four involves input shaft 1 and input shaft 6 rotating in opposite directions, with pulley 17 rotating. In this condition, input shaft 1 drives the secondary center wheel 38 to rotate, which in turn drives the secondary wheel 44 to rotate and revolve. This revolve drives the primary and secondary gear frames 25 to rotate, which in turn drives the primary wheel 29 to rotate around input shaft 6. Because input shaft 6 is rotating in the opposite direction, the speed of the primary wheel 29 relative to input shaft 6 increases, and correspondingly, the speed of the primary and secondary gear frames 25 also increases. This increased speed of the primary and secondary gear frames 25 leads to an increased speed of the secondary wheel 44, resulting in a higher speed for the secondary gear ring 36 than in either operating condition one or two. The secondary gear ring 36 is then output from output terminal 18a after a third-stage transmission. In operating condition four, the relative speed difference between the differential housing pulley 17 and output terminal 18a is higher than in operating conditions one and two. The operator can adjust the speeds of input shaft 1 and input shaft 6 to achieve continuous high-speed output from the tertiary gear frame 18.

[0060] The above four operating conditions cover all working states of the dual-ratio direct-drive differential of this invention. Without changing the speeds of the motors connected to input shaft 1, input shaft 6, and pulley 17, multiple differential ratios can be achieved by switching operating conditions to meet the needs of centrifuges separating different materials. Furthermore, operators can achieve greater speed differences by adjusting the speed and direction of each motor while ensuring they operate within their high-efficiency range, thus meeting the needs of more operating conditions.

[0061] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A dual-ratio direct-drive differential, characterized in that: It includes input shaft one (1), input shaft two (6), bearing housing one (13), first and second stage transmission assembly (I), third stage transmission assembly (II), bearing housing two (20), third stage frame (18) and pulley (17). Input shaft one (1) is fitted into input shaft two (6). The right end of input shaft one (1) is fixedly connected to a secondary center wheel (38), and the right end of input shaft two (6) is provided with a gear. The first and second stage transmission assembly (I) consists of the first stage transmission assembly (III) and the second stage transmission assembly (IV). The first stage transmission assembly (III) and the second stage transmission assembly (IV) share the same first and second stage frame (25). The first stage transmission assembly (III) includes a first stage wheel (29), a first stage bearing (32), a first stage wheel post (31), and a first stage gear ring (24). The first stage gear ring (24) is fixedly connected to the bearing housing (13) by screws. The gear at the right end of the input shaft (6) meshes externally with the first stage wheel (29), and the first stage wheel (29) meshes internally with the first stage gear ring (24). The second stage transmission assembly (IV) includes a second stage wheel (44), a second stage bearing (43), a second stage wheel post (40), and a second stage gear ring (36). The second stage center wheel (38) meshes externally with the second stage wheel (44), and the second stage wheel (44) meshes internally with the second stage gear ring (36). The three-stage transmission assembly (II) includes the external tooth portion (36c) of the second-stage gear ring (36), the third-stage wheel (46), the third-stage gear ring (45), the sliding bearing (47), the third-stage wheel column (49), the left support (48) of the third-stage frame, and the right support (18b) of the third-stage frame. The external tooth portion (36c) of the second-stage gear ring (36) meshes with the third-stage wheel (46) externally, and the third-stage wheel (46) meshes with the third-stage gear ring (45) internally. When the input shaft 1 (1) is connected to the motor and rotates, the input shaft 2 (6) is fixed and does not rotate, and the pulley (17) rotates, the power is transmitted through the input shaft 1 (1) to the secondary transmission assembly (IV) and the tertiary transmission assembly (II) to achieve the first speed ratio; when the input shaft 1 (1) is fixed and does not rotate, the input shaft 2 (6) is connected to the motor and rotates, and the pulley (17) rotates, the power is transmitted through the input shaft 2 (6) to the secondary transmission assembly (IV) and the tertiary transmission assembly (II) to achieve the second speed ratio.

2. A dual-ratio direct-drive differential according to claim 1, characterized in that: The first and second level frames (25) adopt an integrated design. The first and second level frames (25) are provided with a first-level wheel seat cavity (25i), a first-level wheel column lower mounting hole (25g), a first-level wheel column upper mounting hole (25f), a first-level pin hole (25h), a second-level wheel seat cavity (25c), a second-level wheel column lower mounting hole (25e), a second-level wheel column upper mounting hole (25a), a second-level pin hole (25b), a first and second level frame upper support plate (25j), and a first and second level frame lower support plate (25d). The first-level wheel seat cavity (25i) and the second-level wheel seat cavity (25c) are offset in the circumferential direction. The positions are evenly distributed, and the upper support plate (25j) and lower support plate (25d) of the first and second level frames are evenly distributed with the first-level wheel seat cavity (25i) and the second-level wheel seat cavity (25c) respectively. The distances from the lower mounting hole (25g) and upper mounting hole (25f) of the first-level wheel column to the center of the first and second level frames (25) are independently set with respect to the lower mounting hole (25e) and upper mounting hole (25a) of the second-level wheel column to the center of the first and second level frames (25). The number of the first-level wheel seat cavity (25i) and the second-level wheel seat cavity (25c) are equal.

3. A dual-ratio direct-drive differential according to claim 1, characterized in that: The input shaft one (1) is fixed to the input shaft two (6) by bearing one (5) and input shaft bearing (26), and the input shaft two (6) is fixed to the bearing seat one (13) by bearing two (11) and bearing three (14); the input shaft bearing (26) is installed in the input shaft two (6) and is axially positioned by the step of the input shaft two (6) on the left side of the input shaft bearing (26) and the spacer (28) on the right side, and the spacer (28) is axially fixed by shaft clamp five (27); the input shaft one (1) is provided with through oil hole one (1a) and oil hole two (1b), and the input shaft two (6) is provided with through oil hole three (6a) and oil hole four (6a). b), used to lubricate bearing one (5) and input shaft bearing (26); the input shaft one (1) is axially fixed by shaft clamp one (4), the input shaft two (6) is axially fixed by shaft clamp two (12), and the bearing three (14) is axially fixed by shaft clamp three (15); also includes wear-resistant sleeve (7), O-ring (8), oil seal one (3), oil seal two (9), sealing seat one (2) and sealing seat two (10), the wear-resistant sleeve (7) is interference-fitted on the input shaft two (6) with O-ring (8), the oil seal one (3) is installed on the sealing seat one (2), and the oil seal two (9) is installed on the sealing seat two (10) and forms a rotary seal with the wear-resistant sleeve (7).

4. A dual-ratio direct-drive differential according to claim 2, characterized in that: The first-stage wheel (29) has several oil passage holes 5 (29a) at the tooth root and oil passage grooves at both ends; the second-stage wheel (44) has several oil passage holes 15 (44a) at the tooth root and oil passage grooves at both ends; the first-stage wheel post (31) has oil passage hole 9 (31a) and several oil passage holes 10 (31b); the first and second stage frames (25) have oil passage hole 7 (25k), and oil passage hole 9 (31a) and oil passage hole 7 (25k) are axially connected; the second-stage wheel post (40) has oil passage hole 13 (40a) and several oil passage holes 14 (40b); the first and second stage frames (25) It is also provided with an oil passage hole eight (25m), and the oil passage hole thirteen (40a) is axially connected to the oil passage hole eight (25m); the left and right end faces of the first-stage wheel (29) and the first-stage bearing (32) are each provided with a first-stage bearing retaining ring (30), and the left and right end faces of the second-stage wheel (44) and the second-stage bearing (43) are each provided with a second-stage bearing retaining ring (42); the first-stage wheel column (31) is fixed to the first and second stage frame (25) in the axial and circumferential directions by inserting the first-stage pin (33) into the first-stage pin hole (25h), and the second-stage wheel column (40) is fixed to the first and second stage frame (25) in the axial and circumferential directions by inserting the second-stage pin (41) into the second-stage pin hole (25b).

5. A dual-ratio direct-drive differential according to claim 1, characterized in that: The left end face step of the first and second stage frame (25) is axially positioned by the outer ring of bearing four (16), and the right end face step is axially positioned by the inner ring of bearing seven (37); bearing four (16) is set in the seat cavity of bearing seat one (13), and bearing seat one (13) is provided with several oil passage holes six (13a) on the left end face of bearing four (16); the left end of the inner hole of the second stage center wheel (38) is interference-fitted with the left side of the right end of the input shaft one (1), and the right end is connected to the right side of the right end of the input shaft one (1) through a spline transition fit, and is connected through the shaft clip six (39). Axially fixed; the secondary gear ring (36) includes an internal gear part (36a) and an external gear part (36c). The internal gear part (36a) is radially positioned with bearing seat one (13) through bearing six (35). Bearing six (35) is axially fixed through a hole clamp (34). The right end face of the external gear part (36c) is radially positioned with the output end (18a) of the third stage frame (18) through bearing eight (52). An oil passage hole twelve (36d) is provided at the center of the external gear part (36c), and an oil passage hole eleven (36b) is provided on the left side of the external gear part (36c).

6. A dual-ratio direct-drive differential according to claim 1, characterized in that: The outer circumference of the sliding bearing (47) is provided with N intersecting spiral oil grooves. Oil groove one (47a) and oil groove four (47d) form a complete spiral annular oil groove, and oil groove three (47c) and oil groove two (47b) form a complete spiral annular oil groove. The two sets of oil grooves intersect at the midpoint and both ends of the width of the sliding bearing (47) respectively, forming an external combined oil channel that can communicate with each other. The inner hole of the sliding bearing (47) is provided with N intersecting spiral oil grooves. Oil groove five (47e) and oil groove eight (47h) form a complete spiral annular oil groove. A spiral annular oil groove, oil groove six (47f) and oil groove seven (47g) form a complete spiral annular oil groove, and the two sets of oil grooves intersect at the midpoint of the width of the sliding bearing (47) and at both ends respectively, forming an internal combination oil channel that can communicate with each other; the inner hole and outer circle of the sliding bearing (47) are respectively in clearance rotational fit with the outer circle of the third-stage wheel column (49) and the inner hole of the third-stage wheel (46), and the clearance between the inner hole of the sliding bearing (47) and the outer circle of the third-stage wheel column (49) is greater than the clearance between the outer circle of the sliding bearing (47) and the inner hole of the third-stage wheel (46).

7. A dual-ratio direct-drive differential according to claim 1, characterized in that: The third-stage wheel post (49) is provided with a third-stage wheel post notch (49c), a third-stage wheel post oil passage surface (49d), a third-stage wheel post bearing outer circle (49e), an oil passage hole seventeen (49b) penetrating the third-stage wheel post oil passage surface (49d), and an oil passage hole sixteen (49a) penetrating the width direction of the third-stage wheel post (49); the third-stage wheel post oil passage surface (49d) is located in the middle of the width of the third-stage wheel post bearing outer circle (49e) and does not communicate with the two end faces; the third The left support (48) of the frame is provided with a left hole (48c) of the third-stage wheel column, and the right support (18b) of the third-stage frame is provided with a right hole (18c) of the third-stage wheel column and a notched hole (18d) of the third-stage wheel column. The two ends of the third-stage wheel column (49) are respectively engaged with the left hole (48c) and the right hole (18c) of the third-stage wheel column. The notch (49c) of the third-stage wheel column is engaged with the notched hole (18d) of the third-stage wheel column to prevent the third-stage wheel column (49) from rotating.

8. A dual-ratio direct-drive differential according to claim 7, characterized in that: It also includes a positioning pin (50) and a screw (51). The positioning pin (50) is provided with a positioning pin notch (50a). The left support of the third-level frame (48) is provided with a positioning pin notch hole (48a) and a positioning pin left hole (48b). The right support of the third-level frame (18b) is provided with a positioning pin right hole (18e). The positioning pin notch (50a) is installed corresponding to the notch of the positioning pin notch hole (48a) and passes through the positioning pin left hole (48b) and the positioning pin right hole (18e) in sequence. The screw (51) passes through the positioning pin right hole (18e) of the third-level frame right support (18b) and is threadedly fastened to the positioning pin (50), so that the third-level frame left support (48) and the third-level frame right support (18b) form a rigid connection.

9. A dual-ratio direct-drive differential according to claim 1, characterized in that: The outer circumference of the three-stage gear ring (45) is provided with N heat dissipation grooves; the output end (18a) of the three-stage frame (18) is fixed on the bearing seat (20) by two parallel bearing five (19) and axially fixed by the shaft clamp four (21); the bearing seat two (20) is connected to the centrifuge drum and the three-stage frame (18) is connected to the centrifuge rotor; it also includes a sealing seat three (22) and an oil seal three (23), the oil seal three (23) is installed on the sealing seat three (22) to seal the differential output end.

10. A dual-ratio direct-drive differential according to claim 1, characterized in that: When the input shaft one (1) and the input shaft two (6) rotate in the same direction and the pulley (17) rotates, the output speed of the secondary gear ring (36) is lower than the speed under the first speed ratio and the second speed ratio, thus achieving low speed difference output; when the input shaft one (1) and the input shaft two (6) rotate in opposite directions and the pulley (17) rotates, the output speed of the secondary gear ring (36) is higher than the speed under the first speed ratio and the second speed ratio, thus achieving high speed difference output.

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