Miniature zero differential type double-flow transmission gear reducer

Abstract

The invention discloses a miniature zero differential type double-flow transmission gear reduction box which comprises a box body shell, a straight transmission gear set, a steering transmission gear set, a first planetary differential mechanism, a second planetary differential mechanism, a first output gear set and a second output gear set. The straight transmission gear set, the first planetary differential mechanism and the first output gear set are arranged on one side in the box shell, and the steering transmission gear set, the second planetary differential mechanism and the second output gear set are arranged on the other side in the box shell. The first planetary differential mechanism and the second planetary differential mechanism are coaxially arranged and arranged at the two ends of the sun gear shaft correspondingly. The miniature zero differential type double-flow transmission gear reducer can be installed on a miniature crawler-type power platform, has the advantages of being small in size and high in universality, overcomes the defect that crosstalk exists in straight moving power input and steering power input, and achieves high-precision and high-stability rotating speed and torque output of the two extended output shafts.

Description

Technical Field

[0001] The present invention relates to the technical field of miniature tracked dynamic vehicle models and tracked robots, and in particular to a miniature zero-differential double-flow transmission gear reducer suitable for tracked robots with small volumes and electric drive and miniature models of tracked vehicles with a small scale (1 / 30) or less. Background Art

[0002] Micro-tracked power platforms used in miniature tracked vehicle models (miniaturized at 1 / 64, 1 / 72 and 1 / 87 scales of real-world tracked manned combat vehicles and engineering machinery) and tracked robots currently usually use two identical power motors, each driving a track. This has many disadvantages, including the difficulty in synchronizing the speed of the two tracks in the transmission system, the difficulty in accurately controlling the output of the two power motors, the high transmission noise, and the large total space occupied by the two power motors. These limitations limit the application of micro-tracked vehicles using this drive method in entertainment, scientific research, military, small space exploration and rescue, and other fields.

[0003] The power system is the most important part of the micro crawler power platform. Its power, speed rigidity, torque rigidity, and the consistency and stability of the speed and torque output of the drive wheels on both sides have a great impact on the driving, obstacle crossing and climbing performance of the micro crawler power platform. The walking part of the micro crawler power platform is small in size, has many moving parts and a complex structure. Under the existing manufacturing and assembly precision, the size, shape and position errors of each part will deteriorate the driving performance of the micro crawler power platform. The rotational resistance of the driving wheel, road wheel, inducer wheel and track roller will fluctuate greatly during the rotation process, and these wheels (or wheel pairs) may experience eccentricity, yaw and other phenomena during operation. The superposition of these phenomena will cause the resistance of the micro-crawler power platform to constantly change during driving; the track pins and track shoes are small in size and large in number, and the matching accuracy is difficult to guarantee, which will cause the matching clearance of each track shoe and track pin to be different, and the rotational resistance of each track shoe section in a track is different; the dimensional and geometric tolerances of the track pin ears and track inducers will respectively lead to the resistance of different track pin ears when meshing with the driving wheel teeth, and the friction resistance of different track inducers with the road wheels and inducer grooves. In addition, there may be a few track shoes or track pins that scrape against the side of the micro-crawler power platform body. The combination of the above problems ultimately causes the system resistance of the micro crawler power platform to fluctuate greatly and in a complex pattern. The running resistance of the two sets of walking parts on both sides is very different, which puts forward very high requirements on the speed and torque rigidity of the power system of the micro crawler power platform and the consistency control ability of the speed and torque on both sides. Otherwise, there will be problems such as deviation in straight running, driving jam, unstable low-speed speed, and eccentric turning in situ. In addition to the system resistance from the micro crawler power platform, the resistance from the environment also has a great influence on the driving of the micro crawler power platform. When the micro crawler power platform is moving straight, if the friction resistance and / or rolling resistance of the ground contact surface of the crawlers on both sides to the walking system are different, it will cause the linear speed of the crawlers on both sides to be different, which will cause the micro crawler power platform to deviate; when the micro crawler power platform is turning, the ever-changing ground resistance will also cause the steering angular velocity to fluctuate, making it difficult to turn accurately. When turning in situ, it will also cause the steering of the micro crawler power platform to be eccentric, causing the micro crawler power platform to collide with the surrounding environment. Therefore, in order to ensure the driving quality, handling performance and safety of the micro crawler power platform, higher requirements are placed on the performance of the power system.

[0004] Existing micro crawler power platforms all use two motors of the same model and two symmetrically arranged gear reducers to drive the drive wheels on both sides and then drive the crawlers on both sides. Such a power system has the following problems: First, such a power system does not have the ability to ensure that the speed and torque output of the drive wheels on both sides are consistent. Limited by the motor manufacturing process, two motors of the same model will have different output speeds and torques under the same input voltage. This difference will cause the micro crawler power platform to deviate when going straight and deviate from the rotation center when turning on the spot, making such a small-sized platform unable to be used in many occasions that rely on inertial navigation and simple control, and cannot be used for entertainment. On high-precision dynamic models mainly for viewing purposes; secondly, this type of power system is limited by its size, and the two power motors have small power. If a higher maximum speed needs to be achieved, a lower reduction ratio can only be used, which will result in a small output torque of the gearbox and low speed stiffness, ultimately leading to poor low-speed speed stability of the vehicle and inability to run at ultra-low speeds; if the gearbox uses a higher reduction ratio, it will affect the output speed range, and a high reduction ratio requires more gears to achieve, and more gears will increase the difference in transmission resistance of the two gearboxes, increasing the system speed difference of the two gearboxes, and using a higher reduction ratio also means that the size of the two symmetrical reduction gearboxes used in the power system will increase synchronously.

[0005] Therefore, improving the power, speed rigidity, torque rigidity and the consistency and stability of the speed and torque output of the driving wheels on both sides of the micro crawler power platform power system, effectively reducing the influence of the resistance difference and fluctuation of the walking parts on both sides of the micro crawler power platform on the driving speed and direction, and being insensitive to the influence of environmental resistance, and achieving precise control of the speed and direction of the micro crawler power platform under complex road conditions has become the performance goal pursued by the micro crawler power platform. So far, there is no zero-differential dual-flow transmission gear reducer with a small size that can efficiently output bilateral synchronous power, is compatible with small torque motors, and is small enough to be installed in a micro crawler power platform.

[0006] The zero differential double-flow transmission gearbox is usually composed of a housing, a straight-line transmission gear set, a steering transmission gear set, two planetary differentials and two sets of output gear sets. For the miniature zero differential double-flow transmission gearbox, which has not yet been involved in, how to reasonably design the internal structure of the gearbox to ensure the reliable assembly of various shafts, gears, bearings, housings, etc. while the housing size is compact is a certain challenge; in addition, compared with the existing large-scale gearboxes, the motor size of the miniature zero differential double-flow transmission gearbox is small, resulting in high difficulty in motor motion control, low torque and high speed, so the transmission resistance fluctuation of the transmission chain of the gearbox should be small, and it should have a higher reduction ratio; at the same time, in order to make the cost of mass production controllable, the housing and gears should be able to be manufactured in a batch and continuous production manner (such as injection molding), but the housing and gears obtained by this manufacturing method have limited precision and strength, which puts higher requirements on the structural design of the gearbox, that is, through reasonable structural design, ensure that each shaft, gear, bearing, housing, etc. are allowed to have a larger tolerance and lower assembly precision, and meet the strength requirements. It is of great significance to design and mass-produce a miniature zero-differential dual-flow transmission gear reducer and promote its popularization on micro-crawler power platforms, so that the micro-crawler power platforms have better driving performance and can be widely used in entertainment and scientific research, military, micro-space exploration and rescue and other fields. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide a miniature zero-differential dual-flow transmission gear reducer to address the deficiencies in the prior art. The miniature zero-differential dual-flow transmission gear reducer can be installed in a small-scale tracked vehicle model, has the advantages of small size and strong versatility, can reduce the influence of the system and environmental resistance differences and fluctuations of the walking parts on both sides of the vehicle on the vehicle's driving speed and direction, overcomes the deficiency of crosstalk in the two-way power input for straight travel and steering, realizes high-precision and high-stability speed and torque output of the two extended output shafts, and has a wider output speed range.

[0008] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a miniature zero differential double-flow transmission gear reduction box, comprising a housing, a straight transmission gear set, a steering transmission gear set, a first planetary differential, a second planetary differential, a first output gear set and a second output gear set; the straight transmission gear set, the first planetary differential and the first output gear set are arranged on one side of the housing, and the steering transmission gear set, the second planetary differential and the second output gear set are arranged on the other side of the housing; the first planetary differential and the second planetary differential are coaxially arranged and are respectively arranged at both ends of the sun gear shaft; the straight transmission gear set includes a straight power input gear, a bridge gear set, a second idler gear and a straight gear set output gear in sequence from the input end to the output end; the straight power input gear meshes with the gear at the input end of the bridge gear set, and the gear at the output end of the bridge gear set meshes with the second idler gear , the second idler gear meshes with the output gear of the straight gear set, and the output gear of the straight gear set is fixed to the middle of the sun gear shaft; the steering transmission gear set includes a steering power input gear, a third idler gear, a short bridge gear set and a long bridge gear set in sequence from the input end to the output end; the steering power input gear meshes with the third idler gear, and the third idler gear meshes with the gear at the input end of the short bridge gear set, and the gear at the input end of the short bridge gear set meshes with the gear at the input end of the long bridge gear set; the first planetary differential includes a first housing, a first planetary differential outer gear, a plurality of first planetary gears, a first planet carrier and a first sun gear; the gear at the output end of the long bridge gear set meshes with the first planetary differential outer gear; the second planetary differential includes a second housing, a second planetary differential outer gear, a plurality of second planetary gears, a second planet carrier and a second sun gear; the gear at the output end of the short bridge gear set meshes with the second planetary differential outer gear.

[0009] Further, the first planetary differential outer gear is fixed to the first housing, and the first planetary differential outer gear is movably sleeved on the outer periphery of the sun gear shaft; the first planetary gear, the first planet carrier and the first sun gear are arranged inside the first housing, and the first inner gear ring is arranged on the inner ring of the first housing; the first sun gear is fixed to the outer periphery of the sun gear shaft, the first planetary gear is respectively meshed with the first sun gear and the first inner gear ring, the gear shaft of the first planetary gear is installed on the input end of the first planet carrier, and the output shaft of the first planet carrier drives the first output gear set; the second planetary differential outer gear is fixed to the second housing, and the second planetary differential outer gear is movably sleeved on the outer periphery of the sun gear shaft; the second planetary gear, the second planet carrier and the second sun gear are arranged inside the second housing, and the second inner gear ring is arranged on the inner ring of the second housing; the second sun gear is fixed to the outer periphery of the sun gear shaft, the second planetary gear is respectively meshed with the second sun gear and the second inner gear ring, the gear shaft of the second planetary gear is installed on the input end of the second planet carrier, and the output shaft of the second planet carrier drives the second output gear set.

[0010] Further, the first output gear set includes a first planetary carrier output gear that is interference fit with the output shaft of the first planetary carrier, a first output shaft gear that meshes with the first planetary carrier output gear, and a first extended output shaft that is interference fit with the first output shaft gear; the second output gear set includes a second planetary carrier output gear that is interference fit with the output shaft of the second planetary carrier, a second output shaft gear that meshes with the second planetary carrier output gear, and a second extended output shaft that is interference fit with the second output shaft gear.

[0011] Furthermore, a first idler gear is arranged between the straight-line power input gear and the bridge gear set, the straight-line power input gear meshes with the first idler gear, and the first idler gear meshes with the gear at the input end of the bridge gear set; the bridge gear set includes a shaft, two gears assembled at both ends of the shaft by interference fit, and a rolling bearing sleeved in the middle of the shaft; the short bridge gear set and the long bridge gear set both include a shaft, two gears assembled at both ends of the shaft by interference fit, and two rolling bearings sleeved on the shaft and located on the outside of the gears.

[0012] Furthermore, the output gear of the straight gear set is assembled in the middle of the sun gear shaft by interference fit; the two ends of the sun gear shaft are processed into D-shaped cross-sections, the hole cross-sections of the first sun gear and the hole cross-sections of the second sun gear are both D-shaped holes, and the two ends of the sun gear shaft are respectively interference fit with the D-shaped hole of the first sun gear and the D-shaped hole of the second sun gear.

[0013] Further, a first boss is arranged on the outer side surface of the first planetary differential outer gear, the diameter of the center hole of the first boss is larger than the diameter of the first planetary differential outer gear hole, and the center hole of the first boss and the first planetary differential outer gear hole form a coaxial stepped hole; the first housing is interference fit with the center hole of the first boss, and a rolling bearing is arranged between the first planetary differential outer gear hole and the sun gear shaft; a second boss is arranged on the outer side surface of the second planetary differential outer gear, the diameter of the center hole of the second boss is larger than the diameter of the second planetary differential outer gear hole, and the center hole of the second boss and the second planetary differential outer gear hole form a coaxial stepped hole; the second housing is interference fit with the center hole of the second boss, and a rolling bearing is arranged between the second planetary differential outer gear hole and the sun gear shaft.

[0014] Furthermore, the housing includes a first housing shell, a first end cover, a second housing shell and a second end cover; the straight-line transmission gear set and the first planetary differential are arranged inside the second housing shell, and the first output gear set is arranged inside the second end cover; the steering transmission gear set and the second planetary differential are arranged inside the first housing shell, and the second output gear set is arranged inside the first end cover.

[0015] Furthermore, a rolling bearing is arranged between the outer periphery of the first shell and the second housing, a rolling bearing is arranged between the inner hole of the first shell and the sun gear shaft, a rolling bearing is arranged between the outer periphery of the second shell and the first housing, and a rolling bearing is arranged between the inner hole of the second shell and the sun gear shaft; the output shaft of the first planetary carrier passes through the second end cover, and a rolling bearing is arranged between the second end cover, and a sliding bearing is arranged between the first extended output shaft and the second end cover; the output shaft of the second planetary carrier passes through the first end cover, and a rolling bearing is arranged between the first end cover, and a sliding bearing is arranged between the second extended output shaft and the first end cover.

[0016] Furthermore, the center line of the first extended output shaft coincides with the center line of the second extended output shaft, the straight-moving motor and the steering motor are arranged in parallel, the straight-moving motor and the steering motor are both arranged parallel to the center line of the first extended output shaft and the center line of the second extended output shaft, and the diameter of the straight-moving motor and the diameter of the steering motor are both less than 13 mm.

[0017] Furthermore, the center line of the first extended output shaft coincides with the center line of the second extended output shaft, the straight-moving motor and the steering motor are arranged in parallel, and the straight-moving motor and the steering motor are both arranged perpendicular to the center line of the first extended output shaft and the center line of the second extended output shaft; the straight-moving power input gear is driven by the straight-moving motor through a worm gear, and the steering power input gear is driven by the steering motor through a worm gear.

[0018] The beneficial effects of the present invention are:

[0019] 1. The miniature zero-differential dual-flow transmission gear reducer of the present invention is small in size and highly versatile. It can be placed in the power compartments of 1 / 64, 1 / 72 and 1 / 87 tracked vehicle models, and can be easily adapted to the working conditions of different vehicle models by replacing the motor model and the gear set reduction ratio.

[0020] 2. The gears, drive shafts and bearings in the miniature zero-differential dual-flow transmission gear reducer of the present invention have a compact structural design, which solves the problem that the zero-differential dual-flow transmission gear reducer cannot be miniaturized while ensuring the strength of each drive shaft and gear. The gears, shafts and bearings are reasonably arranged in a small space, so that the planetary differential has the advantages of high rotational accuracy and large load-bearing torque, overcomes the shortcoming of crosstalk in the two-way power input for straight travel and steering, and realizes high-precision and high-stability speed and torque output of the two extended output shafts.

[0021] 2.1 The miniature zero-differential dual-flow transmission gear reducer of the present invention transmits the power of the straight-moving motor and the steering motor to the first sun gear and the second sun gear, the first planetary differential outer gear and the second planetary differential outer gear respectively through the straight-moving transmission gear set and the steering transmission gear set. After converging, the power is output to both sides by the first output shaft gear meshed with the first planetary carrier output gear and the second output shaft gear meshed with the second planetary carrier output gear. Through the positioning and constraint of the first housing, the second housing and the sun gear shaft and the case shell, and the positioning and constraint of the first planetary carrier, the second planetary carrier and the case shell, the crosstalk between the two power inputs of the gear box for straight-moving and steering can be effectively reduced, thereby achieving high-precision and high-stability speed and torque output of the two extended output shafts of the gear box.

[0022] 2.2 In the present invention, a rolling bearing is arranged between the outer periphery of the first shell and the second housing, a rolling bearing is arranged between the inner hole of the first shell and the sun gear shaft, a rolling bearing is arranged between the outer periphery of the second shell and the first housing, and a rolling bearing is arranged between the inner hole of the second shell and the sun gear shaft, so as to realize the positioning and constraint of the first shell, the second shell, the sun gear shaft and the housing shell, and solve the problem of poor radial constraint of the differential caused by difficulty in arranging rolling bearings on the sun gear shaft, housing and planetary carrier of the planetary differential due to the limitation of the outer width size of the miniature double-flow transmission gearbox, simplify the housing structure of the planetary differential, and make the planetary differential have high rotational accuracy and large load-bearing torque, and have the advantages of long service life and high reliability.

[0023] 2.3 In the present invention, a rolling bearing is arranged between the output shaft of the first planetary carrier and the second end cover, a sliding bearing is arranged between the first extended output shaft and the second end cover, a rolling bearing is arranged between the output shaft of the second planetary carrier and the first end cover, and a sliding bearing is arranged between the second extended output shaft and the first end cover, so as to realize the positioning and constraint of the first planetary carrier, the second planetary carrier and the housing; the sliding bearing has a long effective contact area, which can effectively ensure the rotation accuracy of the first extended output shaft and the second extended output shaft, and effectively limit the radial runout and runout of the first extended output shaft and the second extended output shaft, avoiding the problem of interference between the gears facing the center side of the gear box body and the corresponding planetary differential when rolling bearings are arranged in pairs on both sides of the first extended output shaft and the second extended output shaft, and reducing the width of the gear box body.

[0024] 3. The straight-moving motor of the present invention adopts a relatively large-power motor, and the reduction ratio of the straight-moving transmission gear set is relatively small, which is beneficial to reducing transmission loss and outputting a relatively high speed while ensuring torque, meeting the requirements of continuous and high-power power output when the tracked vehicle moves straight; the steering motor adopts a relatively small-power motor, and the reduction ratio of the steering transmission gear set is relatively large to amplify the output torque, which meets the working conditions of small power, low speed and intermittent operation required when the tracked vehicle turns, avoiding the waste of power capacity caused by the use of high-power motors and reducing space occupancy.

[0025] 4. The assembly process of the housing, transmission gear set, planetary differential and output gear set in the miniature zero differential double-flow transmission gear reducer of the present invention is simple and easy to operate, and can be conveniently disassembled and assembled repeatedly, which is convenient for maintenance. The equipment used in the present invention to manufacture the housing, transmission gear set, planetary differential and output gear set parts is a continuous molding process equipment (such as an injection molding machine) that is more commonly used in industrial production. Therefore, continuous and batch production can be achieved, the cost is low and the application prospects are broad. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Attached Figure 1 This is a structural diagram of a miniature zero-differential dual-flow transmission gear reduction box of the present invention;

[0027] Attached Figure 2 This is a structural diagram of the miniature zero-differential dual-flow transmission gear reducer of the present invention (with the motor hidden);

[0028] Attached Figure 3 Gear transmission structure diagram of the first planetary differential, the second planetary differential, the first output gear set and the second output gear set of the present invention;

[0029] Attached Figure 4 It is a partial exploded view of the first planetary differential of the present invention;

[0030] Attached Figure 5 It is a partial cutaway view of the first planetary differential of the present invention;

[0031] Attached Figure 6 Another perspective of the partial cutaway view of the first planetary differential of the present invention;

[0032] Attached Figure 7 It is a partial exploded view of the second planetary differential of the present invention;

[0033] Attached Figure 8 is a partial cutaway view of the second planetary differential of the present invention;

[0034] Attached Fig. 9 It is a partial cutaway view of the first housing and the first planetary differential outer gear of the present invention;

[0035] Attached Fig.10 It is a partial cutaway view of the second housing and the second planetary differential outer gear of the present invention;

[0036] Attached Fig.11 This is an internal structure diagram of a miniature zero-differential dual-flow transmission gear reducer in Example 9 of the present invention;

[0037] Attached Fig.12 This is an internal structure diagram of a miniature zero-differential dual-flow transmission gear reducer in Embodiment 10 of the present invention;

[0038] Attached Fig.13 This is an assembly diagram of a miniature zero-differential dual-flow transmission gear reducer in Example 10 of the present invention.

[0039] Description of the reference numerals: housing 1, first housing 11, first end cover 12, second housing 13, second end cover 14, straight driving gear set 2, straight driving power input gear 21, first idler gear 22, bridge gear set 23, second idler gear 24, straight driving gear set output gear 25, straight driving motor 26, steering driving gear set 3, steering power input gear 31, third idler gear 32, short bridge gear set 33, long bridge gear set 34, steering motor 35, first planetary differential 4, first housing 41, first inner gear ring 411, first planetary differential outer gear 42, first boss 421, first planetary differential outer gear hole 4 23, first planetary gear 43, first planetary carrier 44, first sun gear 45, second planetary differential 5, second housing 51, second inner gear ring 511, second planetary differential outer gear 52, second boss 521, second boss center hole 522, second planetary differential outer gear hole 523, second planetary gear 53, second planetary carrier 54, second sun gear 55, first output gear set 6, first planetary carrier output gear 61, first output shaft gear 62, first extended output shaft 63, second output gear set 7, second planetary carrier output gear 71, second output shaft gear 72, second extended output shaft 73, sun gear shaft 8. DETAILED DESCRIPTION

[0040] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0041] Example 1

[0042] A miniature zero differential double flow transmission gear reducer, such as Figure 1 As shown, it includes a housing 1, a straight transmission gear set 2, a steering transmission gear set 3, a first planetary differential 4, a second planetary differential 5, a first output gear set 6 and a second output gear set 7.

[0043] The straight transmission gear set 2, the first planetary differential 4 and the first output gear set 6 are arranged on one side of the housing 1, and the steering transmission gear set 3, the second planetary differential 5 and the second output gear set 7 are arranged on the other side of the housing 1. The first planetary differential 4 and the second planetary differential 5 are coaxially arranged, and are respectively arranged at both ends of the sun gear shaft 8.

[0044] like Figure 2 As shown, the straight transmission gear set 2 includes a straight power input gear 21, a bridge gear set 23, a second idler gear 24 and a straight gear set output gear 25 from the input end to the output end. The straight power input gear 21 meshes with the gear at the input end of the bridge gear set 23, the gear at the output end of the bridge gear set 23 meshes with the second idler gear 24, the second idler gear 24 meshes with the straight gear set output gear 25, and the straight gear set output gear 25 is fixed to the middle of the sun gear shaft 8.

[0045] The steering transmission gear set 3 includes a steering power input gear 31, a third idler gear 32, a short bridge gear set 33 and a long bridge gear set 34 in order from the input end to the output end. The steering power input gear 31 meshes with the third idler gear 32, the third idler gear 32 meshes with the gear at the input end of the short bridge gear set 33, and the gear at the input end of the short bridge gear set 33 meshes with the gear at the input end of the long bridge gear set 34.

[0046] like Figure 2-3 As shown, the first planetary differential 4 comprises a first housing 41, a first planetary differential outer gear 42, a plurality of first planetary gears 43, a first planet carrier 44 and a first sun gear 45. The gear at the output end of the long bridge gear set 34 meshes with the first planetary differential outer gear 42.

[0047] The second planetary differential 5 comprises a second housing 51, a second planetary differential outer gear 52, a plurality of second planetary gears 53, a second planet carrier 54 and a second sun gear 55. The gear at the output end of the short bridge gear set 33 meshes with the second planetary differential outer gear 52.

[0048] The housing 1 is composed of 3-7 parts stacked together, and these housing parts are positioned by two guide pillars that run through the thickness of the housing and fixed by multiple screws. Both the straight drive gear set 2 and the steering drive gear set 3 have drive shafts that need to cross multiple housing parts. The holes on the housing parts that need to pass the drive shafts are slotted to facilitate the overall installation of the drive shafts with gears at both ends, and to facilitate the overall removal of the drive shafts without disassembling the gears at both ends, which is convenient for later maintenance.

[0049] The box shell 1 assembly has a width of less than or equal to 25 mm and a height of less than or equal to 14 mm; the preferred size is 22.3 mm wide and 12 mm high. The box shell 1, the first shell 41, and the second shell 51 are made of high-performance polymer materials or metals, using one or a combination of polyoxymethylene (POM), polyetheretherketone (PEEK), carbon nanofiber reinforced styrene, acrylonitrile and acrylic rubber triblock copolymer (nCF-ASA), titanium alloy, aluminum alloy or copper alloy, and are manufactured using fused deposition 3D printing, injection molding, compression molding, CNC machining, and casting molding processes.

[0050] The gear modules are 0.15, 0.2, 0.3 and 0.4. The gear material is a high-performance polymer material or metal, preferably polyoxymethylene (POM), polyetheretherketone (PEEK), carbon nanofiber reinforced styrene, acrylonitrile and acrylic rubber triblock copolymer (nCF-ASA), titanium alloy, aluminum alloy or copper alloy. The gear is manufactured by fused deposition 3D printing, injection molding, and CNC machining.

[0051] Example 2

[0052] The difference between this embodiment and embodiment 1 is that: Figure 4-6 As shown, the first planetary differential outer gear 42 is fixed to the first housing 41, and the first planetary differential outer gear 42 is movably sleeved on the outer periphery of the sun gear shaft 8. The first planetary gear 43, the first planet carrier 44 and the first sun gear 45 are arranged inside the first housing 41, and the first inner gear ring 411 is arranged on the inner ring of the first housing 41; the first sun gear 45 is fixed to the outer periphery of the sun gear shaft 8, and the first planetary gear 43 is meshed with the first sun gear 45 and the first inner gear ring 411 respectively, and the gear shaft of the first planetary gear 43 is installed on the input end of the first planet carrier 44, and the output shaft of the first planet carrier 44 drives the first output gear set 6.

[0053] like Figure 7-8As shown, the second planetary differential outer gear 52 is fixed to the second housing 51, and the second planetary differential outer gear 52 is movably sleeved on the outer periphery of the sun gear shaft 8. The second planetary gear 53, the second planet carrier 54 and the second sun gear 55 are arranged inside the second housing 51, and the second inner gear ring 511 is arranged on the inner ring of the second housing 51; the second sun gear 55 is fixed to the outer periphery of the sun gear shaft 8, and the second planetary gear 53 is meshed with the second sun gear 55 and the second inner gear ring 511 respectively, and the gear shaft of the second planetary gear 53 is installed on the input end of the second planet carrier 54, and the output shaft of the second planet carrier 54 drives the second output gear set 7.

[0054] Example 3

[0055] The difference between this embodiment and embodiment 2 is that: Figure 2-3 As shown, the first output gear set 6 includes a first planetary carrier output gear 61 which is interference fit with the output shaft of the first planetary carrier 44 , a first output shaft gear 62 which meshes with the first planetary carrier output gear 61 , and a first extended output shaft 63 which is interference fit with the first output shaft gear 62 .

[0056] The second output gear set 7 includes a second planetary carrier output gear 71 which is interference-fitted with the output shaft of the second planetary carrier 54 , a second output shaft gear 72 which meshes with the second planetary carrier output gear 71 , and a second extended output shaft 73 which is interference-fitted with the second output shaft gear 72 .

[0057] Example 4

[0058] The difference between this embodiment and embodiment 1 is that: Figure 2 As shown, a first idler gear 22 is arranged between the straight power input gear 21 and the bridge gear set 23 in the straight transmission gear set 2 , the straight power input gear 21 meshes with the first idler gear 22 , and the first idler gear 22 meshes with the gear at the input end of the bridge gear set 23 .

[0059] The bridge gear set 23 in the linear transmission gear set 2 includes a shaft, two gears assembled at both ends of the shaft with interference fit, and a rolling bearing sleeved in the middle of the shaft.

[0060] The short bridge gear set 33 and the long bridge gear set 34 in the steering transmission gear set 3 both include a shaft, two gears assembled at both ends of the shaft with interference fit, and two rolling bearings sleeved on the shaft and located outside the gears.

[0061] Example 5

[0062] The difference between this embodiment and embodiment 2 is that: Figure 2As shown, the straight gear set output gear 25 is interference fit in the middle of the sun gear shaft 8. Both ends of the sun gear shaft 8 are processed into D-shaped cross sections, and the hole cross sections of the first sun gear 45 and the second sun gear 55 are both D-shaped holes. The two ends of the sun gear shaft 8 are respectively interference fit with the D-shaped holes of the first sun gear 45 and the D-shaped holes of the second sun gear 55.

[0063] Example 6

[0064] The difference between this embodiment and embodiment 2 is that: Fig. 9 As shown, a first boss 421 is provided on the outer side of the first planetary differential external gear 42, the diameter of the first boss center hole 422 is larger than the diameter of the first planetary differential external gear hole 423, and the first boss center hole 422 and the first planetary differential external gear hole 423 form a coaxial stepped hole. The first housing 41 and the first boss center hole 422 are interference fit, and a rolling bearing is provided between the first planetary differential external gear hole 423 and the sun gear shaft 8. The first boss 421 and the first planetary differential external gear 42 are integrally formed or fixed by welding or bonding.

[0065] like Fig.10 As shown, a second boss 521 is provided on the outer side of the second planetary differential external gear 52, the diameter of the second boss center hole 522 is larger than the diameter of the second planetary differential external gear hole 523, and the second boss center hole 522 and the second planetary differential external gear hole 523 form a coaxial stepped hole. The second housing 51 and the second boss center hole 522 are interference fit, and a rolling bearing is provided between the second planetary differential external gear hole 523 and the sun gear shaft 8. The second boss 521 and the second planetary differential external gear 52 are integrally formed or fixed by welding or bonding.

[0066] Example 7

[0067] The difference between this embodiment and embodiment 3 is that: Figure 2 As shown, the housing 1 includes a first housing 11, a first end cover 12, a second housing 13 and a second end cover 14. The straight transmission gear set 2 and the first planetary differential 4 are arranged inside the second housing 13, and the first output gear set 6 is arranged inside the second end cover 14. The steering transmission gear set 3 and the second planetary differential 5 are arranged inside the first housing 11, and the second output gear set 7 is arranged inside the first end cover 12.

[0068] Example 8

[0069] The difference between this embodiment and embodiment 7 is that: Figure 1As shown, a rolling bearing is arranged between the outer periphery of the first shell 41 and the second housing 13, a rolling bearing is arranged between the inner hole of the first shell 41 and the sun gear shaft 8, a rolling bearing is arranged between the outer periphery of the second shell 51 and the first housing 11, and a rolling bearing is arranged between the inner hole of the second shell 51 and the sun gear shaft 8, so that the first shell 41 and the second shell 51 can rotate smoothly around the sun gear shaft 8 relative to the housing 1.

[0070] The output shaft of the first planetary carrier 44 passes through the second end cover 14, and a rolling bearing is arranged between the first planetary carrier 44 and the second end cover 14, and a sliding bearing is arranged between the first extended output shaft 63 and the second end cover 14. The output shaft of the second planetary carrier 54 passes through the first end cover 12, and a rolling bearing is arranged between the first planetary carrier 54 and the first end cover 12, and a sliding bearing is arranged between the second extended output shaft 73 and the first end cover 12.

[0071] The first housing 11 and the second housing 13 are two housing parts located in the middle of the housing, and are used to position and constrain the sun gear shaft and a part of the straight drive gear set. As the core part of the zero-differential dual-flow transmission gearbox of the present invention, they have maintenance-free characteristics and do not require disassembly and maintenance during the life of the gearbox; the first end cover 12 and the second end cover 14 are sequentially assembled and fixed by screws to the outside of the first housing 11 and the second housing 13, and are used to position and constrain the steering drive gear set, another part of the straight drive gear set, the output shaft, the straight motor and the steering motor.

[0072] Example 9

[0073] The difference between this embodiment and embodiment 3 is that: Fig.11 As shown, the center line of the first extended output shaft 63 coincides with the center line of the second extended output shaft 73, the straight-moving motor 26 and the steering motor 35 are arranged in parallel, and the straight-moving motor 26 and the steering motor 35 are both arranged parallel to the center line of the first extended output shaft 63 and the center line of the second extended output shaft 73, and the diameter of the straight-moving motor 26 and the diameter of the steering motor 35 are both less than 13 mm.

[0074] The miniature zero-differential dual-flow transmission gear reducer of this embodiment has a size of 25mm×22.5mm×12.5mm, the straight-moving motor is a 612 hollow cup motor with a two-stage planetary reduction group (reduction ratio of 25) module, with an outer diameter of 6mm and a total length of 22mm, and the steering motor is a 609 hollow cup motor with a three-stage straight-moving reduction gear group (reduction ratio of 125) module, with a total length of 22.5mm; the reduction ratio of the straight-moving transmission gear group 2 is 187 (including the two-stage planetary reduction group), and the reduction ratio of the steering transmission gear group 3 is 403 (including the three-stage planetary reduction group); at a voltage of 3.7v, the maximum straight-moving output speed of the dual-flow transmission gear reducer is 400rpm, and the maximum steering output speed is 50rpm.

[0075] Since the high speed output by the motor is directly reduced by the planetary reduction group, the gear speed of the subsequent transmission gear group is low, so the noise generated by the gear transmission is small, and the double-flow transmission gear reducer has excellent quiet performance. Due to the existence of the planetary reduction group directly connected to the motor output shaft, the torque output by the double-flow transmission gear reducer is amplified by the planetary reduction group and then transmitted to the subsequent gear group, which makes it possible for the subsequent gear group to work normally without low rotational resistance, greatly reducing the precision requirements during assembly and the subsequent lubrication requirements.

[0076] Example 10

[0077] The difference between this embodiment and embodiment 3 is that: Figure 12-13 As shown, the center lines of the first extended output shaft 63 and the second extended output shaft 73 coincide, the straight-moving motor 26 and the steering motor 35 are arranged in parallel, and the straight-moving motor 26 and the steering motor 35 are both arranged perpendicular to the center lines of the first extended output shaft 63 and the second extended output shaft 73. The straight-moving power input gear 21 is driven by the straight-moving motor 26 through a worm gear, and the steering power input gear 31 is driven by the steering motor 35 through a worm gear, and the worm gear converts the rotation direction to be parallel to the center lines of the first extended output shaft 63 and the second extended output shaft 73.

[0078] The size of the double-flow transmission gear reducer in this embodiment is 30mm×20.5mm×10.5mm, the straight motor 26 is a DC motor with an outer diameter of 10mm and a length of 13mm, and the steering motor 35 is a DC motor with an outer diameter of 10mm and a length of 10mm. The reduction ratio of the straight transmission gear set 3 is 60, and the reduction ratio of the steering transmission gear set 3 is 180; at a voltage of 3.7v, the maximum speed of the power unit for straight output is 600rpm, and the maximum speed of the steering output is 80rpm.

[0079] The double-flow transmission gear reducer of this embodiment uses a linear motor and a steering motor that are larger in size than those in Embodiment 9, and has a lower reduction ratio, so the output speed is high and the transmission efficiency is high, and it is suitable for use under high-power and high-speed working conditions.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A miniature zero differential double-flow transmission gear reducer, characterized in that: The invention comprises a housing (1), a straight transmission gear set (2), a steering transmission gear set (3), a first planetary differential (4), a second planetary differential (5), a first output gear set (6) and a second output gear set (7); the straight transmission gear set (2), the first planetary differential (4) and the first output gear set (6) are arranged on one side of the housing (1), and the steering transmission gear set (3), the second planetary differential (5) and the second output gear set (7) are arranged on the other side of the housing (1); the first planetary differential (4) and the second planetary differential (5) are coaxially arranged and are respectively arranged at two ends of a sun gear shaft (8); The linear transmission gear set (2) comprises, from the input end to the output end, a linear power input gear (21), a bridge gear set (23), a second idler gear (24) and a linear gear set output gear (25); the linear power input gear (21) meshes with the gear at the input end of the bridge gear set (23); the gear at the output end of the bridge gear set (23) meshes with the second idler gear (24); the second idler gear (24) meshes with the linear gear set output gear (25); and the linear gear set output gear (25) is fixed to the middle of the sun gear shaft (8); The steering transmission gear set (3) comprises, from the input end to the output end, a steering power input gear (31), a third idler gear (32), a short bridge gear set (33) and a long bridge gear set (34); the steering power input gear (31) meshes with the third idler gear (32), the third idler gear (32) meshes with the gear at the input end of the short bridge gear set (33), and the gear at the input end of the short bridge gear set (33) meshes with the gear at the input end of the long bridge gear set (34); The first planetary differential (4) comprises a first housing (41), a first planetary differential outer gear (42), a plurality of first planetary gears (43), a first planet carrier (44) and a first sun gear (45); the gear at the output end of the long bridge gear set (34) meshes with the first planetary differential outer gear (42); the second planetary differential (5) comprises a second housing (51), a second planetary differential outer gear (52), a plurality of second planetary gears (53), a second planet carrier (54) and a second sun gear (55); the gear at the output end of the short bridge gear set (33) meshes with the second planetary differential outer gear (52).

2. The miniature zero differential dual-flow transmission gear reducer according to claim 1, characterized in that: The first planetary differential outer gear (42) is fixed to the first housing (41), and the first planetary differential outer gear (42) is movably sleeved on the outer periphery of the sun gear shaft (8); the first planetary gear (43), the first planet carrier (44) and the first sun gear (45) are arranged inside the first housing (41), and the inner ring of the first housing (41) is provided with a first inner gear ring (411); the first sun gear (45) is fixed to the outer periphery of the sun gear shaft (8), and the first planetary gear (43) is meshed with the first sun gear (45) and the first inner gear ring (411) respectively; the gear shaft of the first planetary gear (43) is installed on the input end of the first planet carrier (44), and the output shaft of the first planet carrier (44) drives the first output gear set (6); The second planetary differential outer gear (52) is fixed to the second housing (51), and the second planetary differential outer gear (52) is movably sleeved on the outer circumference of the sun gear shaft (8); the second planetary gear (53), the second planet carrier (54) and the second sun gear (55) are arranged inside the second housing (51), and the second inner gear ring (511) is arranged on the inner ring of the second housing (51); the second sun gear (55) is fixed to the outer circumference of the sun gear shaft (8), and the second planetary gear (53) is meshed with the second sun gear (55) and the second inner gear ring (511) respectively; the gear shaft of the second planetary gear (53) is installed on the input end of the second planet carrier (54), and the output shaft of the second planet carrier (54) drives the second output gear set (7).

3. The miniature zero differential dual-flow transmission gear reducer according to claim 2, characterized in that: The first output gear set (6) comprises a first planetary carrier output gear (61) which is interference-fitted with the output shaft of the first planetary carrier (44), a first output shaft gear (62) which meshes with the first planetary carrier output gear (61), and a first extended output shaft (63) which is interference-fitted with the first output shaft gear (62); The second output gear set (7) comprises a second planetary carrier output gear (71) which is interference-fitted with the output shaft of the second planetary carrier (54), a second output shaft gear (72) which meshes with the second planetary carrier output gear (71), and a second extended output shaft (73) which is interference-fitted with the second output shaft gear (72).

4. The miniature zero differential dual-flow transmission gear reducer according to claim 1, characterized in that: A first idler gear (22) is arranged between the straight power input gear (21) and the bridge gear set (23), the straight power input gear (21) meshes with the first idler gear (22), and the first idler gear (22) meshes with a gear at an input end of the bridge gear set (23); The bridge gear set (23) comprises a shaft, two gears assembled at both ends of the shaft with an interference fit, and a rolling bearing sleeved in the middle of the shaft; the short bridge gear set (33) and the long bridge gear set (34) both comprise a shaft, two gears assembled at both ends of the shaft with an interference fit, and two rolling bearings sleeved on the shaft and located outside the gears.

5. The miniature zero differential dual-flow transmission gear reducer according to claim 2, characterized in that: The output gear (25) of the straight gear set is assembled in the middle of the sun gear shaft (8) by interference fit; the two ends of the sun gear shaft (8) are processed into D-shaped cross sections, the hole cross sections of the first sun gear (45) and the hole cross sections of the second sun gear (55) are both D-shaped holes, and the two ends of the sun gear shaft (8) are respectively interference fit with the D-shaped hole of the first sun gear (45) and the D-shaped hole of the second sun gear (55).

6. The miniature zero differential dual-flow transmission gear reducer according to claim 2, characterized in that: A first boss (421) is provided on the outer side surface of the first planetary differential external gear (42); the diameter of the first boss center hole (422) is larger than the diameter of the first planetary differential external gear hole (423); the first boss center hole (422) and the first planetary differential external gear hole (423) form a coaxial stepped hole; the first housing (41) and the first boss center hole (422) are interference fit; a rolling bearing is provided between the first planetary differential external gear hole (423) and the sun gear shaft (8); A second boss (521) is provided on the outer side surface of the second planetary differential external gear (52); the diameter of the second boss center hole (522) is larger than the diameter of the second planetary differential external gear hole (523); the second boss center hole (522) and the second planetary differential external gear hole (523) form a coaxial stepped hole; the second housing (51) and the second boss center hole (522) are interference fit; a rolling bearing is provided between the second planetary differential external gear hole (523) and the sun gear shaft (8).

7. The miniature zero differential dual-flow transmission gear reducer according to claim 3, characterized in that: The housing (1) comprises a first housing shell (11), a first end cover (12), a second housing shell (13) and a second end cover (14); the straight transmission gear set (2) and the first planetary differential (4) are arranged inside the second housing shell (13), and the first output gear set (6) is arranged inside the second end cover (14); the steering transmission gear set (3) and the second planetary differential (5) are arranged inside the first housing shell (11), and the second output gear set (7) is arranged inside the first end cover (12).

8. The miniature zero differential dual-flow transmission gear reducer according to claim 7, characterized in that: A rolling bearing is arranged between the outer periphery of the first shell (41) and the second housing (13), a rolling bearing is arranged between the inner hole of the first shell (41) and the sun gear shaft (8), a rolling bearing is arranged between the outer periphery of the second shell (51) and the first housing (11), and a rolling bearing is arranged between the inner hole of the second shell (51) and the sun gear shaft (8); The output shaft of the first planetary carrier (44) passes through the second end cover (14), and a rolling bearing is arranged between the first planetary carrier and the second end cover (14), and a sliding bearing is arranged between the first extended output shaft (63) and the second end cover (14); the output shaft of the second planetary carrier (54) passes through the first end cover (12), and a rolling bearing is arranged between the first planetary carrier and the first end cover (12), and a sliding bearing is arranged between the second extended output shaft (73) and the first end cover (12).

9. The miniature zero differential dual-flow transmission gear reducer according to claim 3, characterized in that: The center line of the first extended output shaft (63) coincides with the center line of the second extended output shaft (73); the straight-moving motor (26) and the steering motor (35) are arranged in parallel; the straight-moving motor (26) and the steering motor (35) are both arranged parallel to the center line of the first extended output shaft (63) and the center line of the second extended output shaft (73); and the diameter of the straight-moving motor (26) and the diameter of the steering motor (35) are both less than 13 mm.

10. The miniature zero differential dual-flow transmission gear reducer according to claim 3, characterized in that: The center line of the first extended output shaft (63) coincides with the center line of the second extended output shaft (73); the straight-moving motor (26) and the steering motor (35) are arranged in parallel; the straight-moving motor (26) and the steering motor (35) are both arranged perpendicular to the center line of the first extended output shaft (63) and the center line of the second extended output shaft (73); the straight-moving power input gear (21) is driven by the straight-moving motor (26) through a worm gear, and the steering power input gear (31) is driven by the steering motor (35) through a worm gear.

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