Novel four-phase RV speed reducer and working method thereof

Abstract

The invention provides a novel four-phase RV speed reducer and a working method thereof, and relates to the technical field of RV speed reducers, the novel four-phase RV speed reducer comprises a pin wheel housing assembly, an output shaft assembly, an input shaft assembly, an eccentric shaft assembly and four cycloidal gears; the input shaft assembly drives the eccentric shaft assembly to rotate, the eccentric shaft assembly rotates and revolves around the input shaft assembly under the action of the supporting bearing and the cycloidal gear, the output shaft assembly rotates around the center line of the input shaft assembly under the driving of the mounting bearing and the eccentric shaft assembly, and therefore the effects of reducing the rotating speed and increasing the torque are achieved. The four cycloidal gears are evenly distributed in a 90-degree four-phase mode or oppositely arranged in a 180-degree mode in pairs, and a single set of oppositely-arranged resultant force in a traditional structure is decomposed into four-phase evenly-distributed tangential force or two sets of oppositely-arranged resultant force, so that the purposes of improving stress uniformity of the eccentric shaft, the cycloidal gears and the roller pins and reducing contact force and eccentric loading and eccentric abrasion are achieved, and the bearing capacity and transmission rigidity of the speed reducer are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of RV reducers, and in particular to a novel four-phase RV reducer and a working method thereof. Background Art

[0002] The RV reducer is a key basic component of the robot. Its transmission stiffness and load-bearing capacity have an important impact on the accuracy and service life of the whole machine. The mainstream RV reducer achieves high-speed ratio secondary reduction through the combination of planetary gear transmission and differential gear transmission. The force transmission law of its second reduction part is similar to that of the harmonic reducer. The cycloid wheel driven by the crank replaces the elliptical harmonic generator and its flexible wheel. The invention with publication number CN118462789A discloses a new three-phase RV reducer and its working method. In this invention scheme, the eccentric directions of the three cycloid wheels are evenly distributed at 120°, which decomposes the single set of opposing combined forces in the traditional structure into three-phase evenly distributed tangential forces, so that while keeping the transmission ratio unchanged and the width direction slightly increased, the force is more uniform and the transmission is smoother. Although the three-phase evenly distributed method can effectively reduce the alternating overturning torque on the drive shaft of the mainstream RV reducer, it still has the following shortcomings: 1. The load-bearing capacity has high requirements on the manufacturing process and material selection of the cycloid wheel. If the shaping amount of the cycloid wheel is not properly controlled, it may cause problems such as accelerated wear of the needle teeth and breakage of the needle teeth, thereby reducing the load-bearing capacity of the whole machine and being unable to cope with high-speed and heavy-load conditions; 2. The transmission stability is insufficient. The three-phase evenly distributed tangential force can easily cause stress concentration on the drive shaft and dynamic imbalance during operation, resulting in eccentric wear of the main shaft and its supports and reduced transmission accuracy. Summary of the invention

[0003] The present invention discloses a novel four-phase RV reducer, which can solve the problem of insufficient transmission stability of a novel three-phase RV reducer. The novel four-phase RV reducer adopts a cycloidal wheel with four phases evenly distributed or two-by-two symmetry to further decompose the three-phase evenly distributed tangential force into four-phase evenly distributed tangential forces or two groups of opposing combined forces, which can effectively reduce the stress concentration phenomenon of the transmission shaft, thereby improving the load-bearing capacity, reducing the friction and wear of the main shaft support, improving the transmission stability, and improving the transmission accuracy and rigidity of the RV reducer.

[0004] The present invention adopts the following scheme:

[0005] A novel four-phase RV reducer comprises a pinion gear housing assembly, an output shaft assembly, an input shaft assembly, a plurality of eccentric shaft assemblies evenly distributed around the circumference, and four cycloid wheels;

[0006] The pin gear housing assembly comprises a pin gear housing and a needle roller rotatably mounted on the pin gear housing;

[0007] The output shaft assembly comprises an output shaft, a planet carrier and an output end cover, wherein the output shaft and the output end cover are respectively fixedly connected to the two ends of the planet carrier by screws, and the planet carrier and the output end cover are rotatably mounted in the pin gear housing by bearings;

[0008] The input shaft assembly comprises an input shaft and a sun gear connected to the input shaft; the input shaft assembly is rotatably mounted in the output shaft assembly via an input shaft bearing;

[0009] The eccentric shaft assembly includes an eccentric shaft, a planetary wheel connected to the eccentric shaft, and four eccentric bearing parts respectively used to install eccentric wheel bearings, which are 90° or 90°, 180°, and -90° apart in phase, so as to decompose the tangential force into four-phase evenly distributed tangential forces or decompose into two groups of opposing resultant forces, thereby reducing the stress concentration on the input shaft; the planetary wheel is rotatably mounted on the planetary carrier;

[0010] The pin gear housing is also equipped with four cycloid wheels that mesh with the pin gear housing and its needle rollers, and the four cycloid wheels are sleeved on each eccentric shaft assembly through an eccentric wheel bearing;

[0011] The input shaft assembly is used to drive the eccentric shaft assembly to rotate through the meshing transmission of the sun gear and the planetary gear, thereby realizing the first-stage deceleration; when the eccentric shaft assembly rotates, the four cycloid wheels are respectively driven to make circular translation through the four sets of eccentric shaft bearings, and while the four cycloid wheels make circular translation, they are meshed with the needle rollers arranged on the pin gear housing assembly, so that the cycloid wheels rotate in the opposite direction around the central axis of the input shaft, and then drive the planetary carrier and the output shaft to rotate through the eccentric shaft assembly, and the decelerated rotation is output outwardly through the output shaft, thereby realizing the second-stage deceleration.

[0012] Further, the input shaft assembly is rotatably mounted in the output shaft assembly through a first input shaft bearing and a second input shaft bearing; each of the eccentric shaft assemblies also includes a first bearing, a second bearing, a first eccentric shaft bearing, a second eccentric shaft bearing, a third eccentric shaft bearing, and a fourth eccentric shaft bearing, and each eccentric shaft is rotatably mounted in the output shaft assembly through the first bearing and the second bearing respectively; the cycloid wheel respectively includes a first cycloid wheel, a second cycloid wheel, a third cycloid wheel, and a fourth cycloid wheel installed on the eccentric shaft through a first eccentric shaft bearing, a second eccentric shaft bearing, a third eccentric shaft bearing, and a fourth eccentric shaft bearing.

[0013] Furthermore, the eccentric shaft includes a first bearing portion, a first eccentric bearing portion, a second eccentric bearing portion, a third eccentric bearing portion, a fourth eccentric bearing portion, and a second bearing portion; the first bearing, the first eccentric shaft bearing, the second eccentric shaft bearing, the third eccentric shaft bearing, the fourth eccentric shaft bearing, and the second bearing are respectively installed on the first bearing portion, the first eccentric bearing portion, the second eccentric bearing portion, the third eccentric bearing portion, the fourth eccentric bearing portion, and the second bearing portion of the eccentric shaft by interference fit.

[0014] Furthermore, the eccentric shaft is also provided with a plurality of grooves for installing elastic retaining rings, which are used to realize the axial positioning of the first bearing, the first eccentric shaft bearing, the fourth eccentric shaft bearing and the second bearing, and the first bearing and the corresponding step surface are limitedly installed through the elastic retaining ring and the sleeve; at the same time, a step surface is provided to cooperate with the second eccentric shaft bearing and the third eccentric shaft bearing to realize axial positioning; the planetary gear is fixedly connected to the eccentric shaft through the elastic retaining ring and the keyway, and the second bearing is pressed on the corresponding step surface of the eccentric shaft to realize the limited installation.

[0015] Further, the eccentric directions of the first eccentric bearing part, the second eccentric bearing part, the third eccentric bearing part and the fourth eccentric bearing part can be alternated by 90° in sequence, that is, they are evenly distributed in four phases at 90°, or the eccentric directions of the first eccentric bearing part and the fourth eccentric bearing part can be alternated by 180°, and the eccentric directions of the second eccentric bearing part and the third eccentric bearing part can be alternated by 180°, that is, two groups are distributed oppositely; the first cycloidal wheel, the second cycloidal wheel, the third cycloidal wheel and the fourth cycloidal wheel are respectively interference fit with the outer rings of the first eccentric shaft bearing, the second eccentric shaft bearing, the third eccentric shaft bearing and the fourth eccentric shaft bearing to achieve a rotational connection with the eccentric shaft assembly and to achieve axial positioning; the first cycloidal wheel, the second cycloidal wheel, the third cycloidal wheel and the fourth cycloidal wheel are respectively meshed with the pinion housing and its needle roller.

[0016] Furthermore, the needle gear housing assembly also includes a housing end cover; the needle gear housing is provided with an arc groove for rotatably installing a needle roller, and a needle roller positioning step for installing an annular gasket, and grooves are provided on both sides of the arc groove to install an elastic retaining ring for axially positioning the annular gasket; the inner wall surface of the needle gear housing is provided with a first needle gear housing step and a second needle gear housing step, and the output end cover is provided with a stopper to press the first needle gear housing bearing onto the first needle gear housing step to achieve axial positioning; the second needle gear housing bearing is pressed onto the second needle gear housing step by the planetary carrier to achieve axial positioning.

[0017] Furthermore, the output shaft assembly is rotatably mounted in the needle gear housing assembly through the first needle gear housing bearing and the second needle gear housing bearing; the output end cover is fixedly connected to the planetary carrier by screws, one end of the output shaft is fixedly connected to the planetary carrier, and the other end is provided with an output shaft keyway for the speed and torque output of the reducer; the output end cover is rotatably mounted on the needle gear housing through the first needle gear housing bearing, and the planetary carrier is rotatably mounted on the needle gear housing through the second needle gear housing bearing; the output end cover and the planetary carrier respectively press the first needle gear housing bearing and the second needle gear housing bearing inner ring to achieve axial positioning.

[0018] Furthermore, the number of eccentric shaft assemblies uniformly distributed around the circumference is three or more; one end of each of the eccentric shafts is rotatably mounted on the output end cover via a first bearing; the other end of each of the eccentric shafts is rotatably mounted on the planet carrier via a second bearing.

[0019] Furthermore, the input shaft is rotatably mounted on the output end cover and the planet carrier through a first input shaft bearing and a second input shaft bearing respectively; the input shaft is axially positioned with the first input shaft bearing and the second input shaft bearing through interference fit or through a shoulder arranged on the input shaft.

[0020] The present invention also provides a novel working method of a four-phase RV reducer, comprising the following steps:

[0021] The motor transmits power to the input shaft, which meshes with the sun gear and the planetary gear to form the first stage reduction part; the planetary gear rotates to drive the eccentric shaft to rotate, and the force of the eccentric shaft is transmitted to the needle roller on the pinion housing through the eccentric shaft bearing and the four cycloid wheels, and then the reaction force of the needle roller drives the four cycloid wheels to rotate in the opposite direction, thereby driving the eccentric shaft to revolve around the central axis of the input shaft; the eccentric shaft drives the output end cover and the planetary carrier to revolve around the central axis of the input shaft through the first bearing and the second bearing respectively, and the output shaft and the output end cover are fixedly connected to the planetary carrier, so that the three rotate in the opposite direction around the center line of the input shaft together, realizing the second stage reduction, thereby realizing high reduction ratio transmission.

[0022] Beneficial effects:

[0023] When the first eccentric bearing part, the second eccentric bearing part, the third eccentric bearing part and the fourth eccentric bearing part are evenly distributed at 90°, the four cycloid wheels installed on the eccentric shaft are evenly distributed at 90°; the eccentric direction phases of the first eccentric bearing part, the second eccentric bearing part, the third eccentric bearing part and the fourth eccentric bearing part differ by 90°, 180° and -90° respectively, that is, the eccentric directions of the first eccentric bearing part and the fourth eccentric bearing part are alternately 180°, and the eccentric directions of the second eccentric bearing part and the third eccentric bearing part are alternately 180°, the eccentric directions of the first cycloid wheel and the fourth cycloid wheel, and the second cycloid wheel and the third cycloid wheel installed on the eccentric shaft are symmetrical in pairs, and the eccentric directions are alternately 180°. Both eccentric distribution conditions effectively reduce the stress concentration phenomenon on the eccentric shaft, reduce the friction and wear of the eccentric shaft support, and increase the stability of the transmission; the driving force of the roller on the pinion housing on the cycloid wheel can also be decomposed into four-phase evenly distributed tangential force or two groups of opposing forces, thereby achieving the purpose of improving the uniform force on the crankshaft, cycloid wheel and needle roller, reducing contact force and eccentric load and wear, and improving the load-bearing capacity and transmission stiffness of the reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the full cross-section structure of a new type of four-phase RV reducer.

[0025] Figure 2 It is a structural diagram of the first stage reduction in a new type of four-phase RV reducer - planetary gear transmission.

[0026] Figure 3 It is a structural diagram of the second stage reduction in a new type of four-phase RV reducer - the pinwheel cycloid transmission.

[0027] Figure 4 It is a cross-sectional schematic diagram of the pinion gear housing in a new four-phase RV reducer.

[0028] Figure 5 This is a schematic diagram of the output end cover in a new four-phase RV reducer.

[0029] Figure 6 It is a schematic diagram of the input shaft in a new four-phase RV reducer.

[0030] Figure 7 It is a schematic diagram of the eccentric shaft in a new four-phase RV reducer.

[0031] Figure 8 This is a schematic diagram of the planetary carrier in a new four-phase RV reducer.

[0032] Fig. 9 This is another schematic diagram of the planetary carrier in a new four-phase RV reducer.

[0033] Fig.10This is a schematic diagram of the output shaft in a new four-phase RV reducer. DETAILED DESCRIPTION

[0034] Example 1

[0035] Combination Figures 1 to 10 As shown, this embodiment provides a new type of four-phase RV reducer, a new type of four-phase RV reducer, including a pinion gear housing assembly, an input shaft assembly, an output shaft assembly, a plurality of eccentric shaft assemblies evenly distributed around the circumference, and four cycloid wheels; the input shaft assembly drives the eccentric shaft assembly to rotate through the meshing transmission of the sun gear 8 and the planetary gear 7 rotatably mounted on the planetary carrier 11, thereby realizing a first-stage reduction; the eccentric shaft assembly is provided with four eccentric bearings with phases that differ by 90° or by 90°, 180°, and -90°, respectively, and then four groups of eccentric shaft bearings are used to drive the four cycloid wheels to perform circumferential translation respectively, and the cycloid wheels are meshed with the pinion gear housing 17 and its needle roller 5 while performing circumferential translation, so that the cycloid wheels rotate in the opposite direction around the axis of the input shaft 20, and then the planetary carrier 11 is driven to rotate through the eccentric shaft assembly and the reduction rotation is output outwardly through the output shaft 10, thereby realizing a second-stage reduction. In summary, a two-stage reduction is realized.

[0036] like Figure 1 As shown, the pin gear housing assembly includes a pin gear housing 17, a needle roller 5 rotatably mounted on the pin gear housing 17, and a housing end cover 24, and the housing end cover 24 is fixedly connected to the pin gear housing 17 by screws 9; the output shaft assembly includes an output end cover 19, a planet carrier 11, and an output shaft 10; the output shaft assembly is rotatably mounted in the pin gear housing assembly by a first pin gear housing bearing 18 and a second pin gear housing bearing 12; the input shaft assembly includes an input shaft 20 and a sun gear 8; the input shaft assembly is rotatably mounted in the output shaft assembly by a first input shaft bearing 21 and a second input shaft bearing 25 Each eccentric shaft assembly includes an eccentric shaft 22, a planetary gear 7, a first bearing 23, a second bearing 6, a first eccentric shaft bearing 1, a second eccentric shaft bearing 2, a third eccentric shaft bearing 3, and a fourth eccentric shaft bearing 4. Each eccentric shaft 22 is rotatably mounted in the output shaft assembly through the first bearing 23 and the second bearing 6 respectively; the first cycloid wheel 16, the second cycloid wheel 15, the third cycloid wheel 14, and the fourth cycloid wheel 13 are respectively mounted on the eccentric shaft 22 through the first eccentric shaft bearing 1, the second eccentric shaft bearing 2, the third eccentric shaft bearing 3, and the fourth eccentric shaft bearing 4;

[0037] like Figure 4 , Figure 5As shown, the needle gear housing 17 is provided with an arc groove 27 for rotatably installing the needle roller 5, and a needle roller positioning step for installing the annular gasket 46, and grooves are provided on both sides of the arc groove 27 to install the elastic retaining ring 47 for axially positioning the annular gasket 46; the inner wall surface of the needle gear housing 17 is provided with a first needle gear housing step 29 and a second needle gear housing step 28, and the output end cover 19 is provided with a stopper to press the first needle gear housing bearing 18 on the first needle gear housing step 29 to achieve axial positioning; the second needle gear housing bearing 12 is pressed on the second needle gear housing step 28 by the planetary carrier 11 to achieve axial positioning;

[0038] like Figure 1 , Fig.10 As shown, the output shaft assembly includes an output end cover 19, a planet carrier 11, and an output shaft 10; the output end cover 19 is fixedly connected to the planet carrier 11 by screws 9, one end of the output shaft 10 is fixedly connected to the planet carrier 11 by screws 9, and the other end is provided with an output shaft keyway 45 for the speed and torque output of the reducer; the output end cover 19 is rotatably mounted on the pinion housing 17 through the first pinion housing bearing 18, and the planet carrier 11 is rotatably mounted on the pinion housing 17 through the second pinion housing bearing 12; the output end cover 19 and the planet carrier 11 respectively press the inner rings of the first pinion housing bearing 18 and the second pinion housing bearing 12 to achieve axial positioning;

[0039] like Figure 7 As shown, the eccentric shaft 22 includes a first bearing portion 33, a second bearing portion 38, a first eccentric bearing portion 34, a second eccentric bearing portion 35, a third eccentric bearing portion 36, and a fourth eccentric bearing portion 37; the first bearing 23, the second bearing 6, the first eccentric shaft bearing 1, the second eccentric shaft bearing 2, the third eccentric shaft bearing 3, and the fourth eccentric shaft bearing 4 are respectively installed on the first bearing portion 33, the second bearing portion 38, the first eccentric bearing portion 34, the second eccentric bearing portion 35, the third eccentric bearing portion 36, and the fourth eccentric bearing portion 37 of the eccentric shaft 22 by interference fit;

[0040] Furthermore, the eccentric shaft 22 is also provided with a plurality of grooves for installing other elastic retaining rings, which are used to realize the axial positioning of the first bearing 23, the first eccentric shaft bearing 1, the fourth eccentric shaft bearing 4, and the second bearing 6, and the first bearing 23 is installed with the corresponding step surface through the elastic retaining ring and the sleeve; at the same time, a step surface is provided to cooperate with the second eccentric shaft bearing 2 and the third eccentric shaft bearing 3 to realize axial positioning; the planetary gear 7 is fixedly connected to the eccentric shaft 22 through the elastic retaining ring and the keyway, and the second bearing 6 is pressed on the corresponding step surface of the eccentric shaft 22 to realize the limited installation.

[0041] In this embodiment, the eccentric direction phases of the first eccentric bearing portion 34, the second eccentric bearing portion 35, the third eccentric bearing portion 36 and the fourth eccentric bearing portion 37 can differ by 90° in sequence, forming a four-phase evenly distributed configuration, or can differ by 90°, 180°, and -90° in sequence; the first cycloidal wheel 16, the second cycloidal wheel 15, the third cycloidal wheel 14, and the fourth cycloidal wheel 13 are respectively interference fit with the outer rings of the first eccentric shaft bearing 1, the second eccentric shaft bearing 2, the third eccentric shaft bearing 3, and the fourth eccentric shaft bearing 4 to achieve a rotational connection with the eccentric shaft assembly and achieve axial positioning; the first cycloidal wheel 16, the second cycloidal wheel 15, the third cycloidal wheel 14, and the fourth cycloidal wheel 13 are respectively meshed with the pinion housing 17 and its needle roller 5.

[0042] In this embodiment, the number of eccentric shaft assemblies uniformly distributed around the circumference is three; one end of each of the eccentric shafts 22 is rotatably mounted on the output end cover 19 via a first bearing 23; the other end of each of the eccentric shafts 22 is rotatably mounted on the planet carrier 11 via a second bearing 6;

[0043] like Figure 8 , Fig. 9 , Fig.10 As shown, the planet carrier 11 has two or three through holes 40 evenly distributed around the circumference relative to the central axis, which is the same as the number of the eccentric shaft 22, and is used to install the second bearing 6. Two or three columns 41 are provided, which are the same as the number of the output end cover countersunk holes 31. The columns 41 are provided with first threaded holes 42, which are connected to the output end cover 19 by screws 9. A step 39 is provided for axial positioning of the second pin gear housing bearing 12. A planet carrier groove 43 is provided on the opposite side for installing the sun gear 8 and the planet gear 7, which can reduce the axial size of the reducer as a whole, and a second threaded hole 44 is provided for connecting with the output shaft 10.

[0044] The input shaft 20 is rotatably mounted on the output end cover 19 and the planet carrier 11 through the first input shaft bearing 21 and the second input shaft bearing 25; the input shaft 20 is axially positioned with the first input shaft bearing 21 and the second input shaft bearing 25 through interference fit or shoulder; a coaxial sun gear 8 is provided at one end of the input shaft 20 facing the planet carrier 11, and the sun gear 8 and the input shaft 20 can be integrally processed, and the sun gear 8 is meshed with the planet gear 7 mounted on the eccentric shaft 22 for transmission; an input shaft keyway 32 is provided at the other end of the input shaft 20 for power input;

[0045] In other embodiments, the sun gear 8 and the input shaft 20 may also be processed separately, and the sun gear 8 may be coaxially fixedly mounted on the end surface of the input shaft 20 by bolt connection, key connection or interference fit;

[0046] Each eccentric shaft bearing, input shaft bearing and pinion housing bearing mentioned in this embodiment may be a needle roller bearing, an angular contact ball bearing, or a tapered roller bearing or a deep groove ball bearing.

[0047] In this embodiment, when the first eccentric bearing portion 34, the second eccentric bearing portion 35, the third eccentric bearing portion 36 and the fourth eccentric bearing portion 37 are evenly distributed at 90°, the four cycloid wheels installed on the eccentric shaft 22 are evenly distributed at 90°; the eccentric direction phases of the first eccentric bearing portion 34, the second eccentric bearing portion 35, the third eccentric bearing portion 36 and the fourth eccentric bearing portion 37 differ by 90°, 180°, and -90° respectively, that is, when the eccentric directions of the first eccentric bearing portion 34 and the fourth eccentric bearing portion 37 are alternately 180°, and the eccentric directions of the second eccentric bearing portion 35 and the third eccentric bearing portion 36 are alternately 180°, the first cycloid wheel 16 and the fourth cycloid wheel 13, and the second cycloid wheel 15 and the third cycloid wheel 14 installed on the eccentric shaft 22 are symmetrical in pairs, and the eccentric directions are alternately 180°. Both eccentric distribution conditions effectively reduce the stress concentration phenomenon on the eccentric shaft, reduce the friction and wear of the eccentric shaft 22 support, and increase the stability of the transmission; the driving force of the needle roller 5 on the pinion housing 17 on the cycloid wheel can also be decomposed into four-phase uniformly distributed tangential force or two groups of opposing combined forces, thereby achieving the purpose of improving the uniform force on the crankshaft, cycloid wheel and needle roller, reducing contact force and eccentric load and wear, and improving the load-bearing capacity and transmission stiffness of the reducer.

[0048] Example 2

[0049] The present invention also provides a novel working method of a four-phase RV reducer, and the working method is as follows: the motor transmits power to the input shaft 20 through the input shaft keyway 32, and the sun gear 8 meshes with the planetary gear 7 to form the first stage reduction part, and the planetary gear 7 drives the eccentric shaft 22 to rotate, and the force of the eccentric shaft 22 is transmitted to the needle roller 5 on the pin gear housing 17 through each eccentric shaft bearing and four cycloidal wheels, and then the reaction force of the needle roller 5 drives the four cycloidal wheels to rotate in the opposite direction, thereby driving the eccentric shaft 22 to revolve around the center line of the input shaft 20, and the eccentric shaft 22 drives the output end cover 19 and the planetary carrier 11 to revolve around the center line of the input shaft 20 through the first bearing 23 and the second bearing 6 respectively, and the output shaft 10 and the output end cover 19 are connected to the planetary carrier 11 through the screw 9, so that the three rotate in the opposite direction around the center line of the input shaft 20 together, realizing the second stage reduction, thereby realizing high reduction ratio transmission. Through this embodiment, the stress concentration phenomenon on the eccentric shaft is effectively reduced, the friction and wear of the eccentric shaft 22 support are reduced, and the stability of the transmission is increased.

[0050] It should be understood that the above are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention.

[0051] The above description of the drawings used in the implementation manner only illustrates certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

Claims

1. A novel four-phase RV reducer, comprising a pinion gear housing assembly, an output shaft assembly, an input shaft assembly, and a plurality of eccentric shaft assemblies uniformly distributed around the circumference, wherein the pinion gear housing assembly comprises a pinion gear housing and a needle roller rotatably mounted on the pinion gear housing; the output shaft assembly comprises an output shaft, a planetary carrier, and an output end cover, wherein the output shaft and the output end cover are respectively fixedly connected to both ends of the planetary carrier by screws, and the planetary carrier and the output end cover are rotatably mounted in the pinion gear housing through bearings; the input shaft assembly comprises an input shaft and a sun gear connected to the input shaft; the input shaft assembly is rotatably mounted in the output shaft assembly through an input shaft bearing; and characterized in that, Each of the eccentric shaft assemblies comprises an eccentric shaft, a planetary wheel fixedly connected to the eccentric shaft, and four eccentric bearing parts respectively used to install eccentric wheel bearings, which are phase-separated by 90° or phase-separated by 90°, 180°, and -90°, so as to decompose the tangential force into four-phase evenly distributed tangential forces or decompose into two groups of opposing resultant forces, thereby reducing the stress concentration on the input shaft; the planetary wheel is rotatably mounted on the planetary carrier; The pin gear housing is also provided with four cycloid wheels which are meshed with the pin gear housing and its needle rollers for transmission, and the four cycloid wheels are sleeved on each eccentric shaft assembly through an eccentric wheel bearing; The input shaft assembly is used to drive the eccentric shaft assembly to rotate through the meshing transmission of the sun gear and the planetary gear, thereby realizing the first-stage deceleration; when the eccentric shaft assembly rotates, the four cycloid wheels are respectively driven to make circular translation through the four sets of eccentric shaft bearings, and while the four cycloid wheels make circular translation, they are meshed with the needle rollers arranged on the pin gear housing assembly, so that the cycloid wheels rotate in the opposite direction around the central axis of the input shaft, and then drive the planetary carrier and the output shaft to rotate through the eccentric shaft assembly, and the decelerated rotation is output outwardly through the output shaft, thereby realizing the second-stage deceleration.

2. According to the novel four-phase RV reducer of claim 1, it is characterized in that: The eccentric shaft is packaged with 10000 The output shaft assembly comprises a first bearing portion, a first eccentric bearing portion, a second eccentric bearing portion, a third eccentric bearing portion, a fourth eccentric bearing portion, and a second bearing portion; each of the eccentric shaft assemblies also comprises a first bearing, a first eccentric shaft bearing, a second eccentric shaft bearing, a third eccentric shaft bearing, a fourth eccentric shaft bearing, and a second bearing, and each of the eccentric shafts is rotatably mounted in the output shaft assembly through the first bearing and the second bearing respectively; the cycloid wheel comprises a first cycloid wheel, a second cycloid wheel, a third cycloid wheel, and a fourth cycloid wheel mounted on the eccentric shaft through the first eccentric shaft bearing, the second eccentric shaft bearing, the third eccentric shaft bearing, and the fourth eccentric shaft bearing respectively.

3. According to the novel four-phase RV reducer of claim 2, it is characterized in that: The eccentric shaft is also provided with a plurality of grooves for installing elastic retaining rings, which are used to realize the axial positioning of the first bearing, the first eccentric shaft bearing, the fourth eccentric shaft bearing and the second bearing, and the first bearing and the corresponding step surface are limitedly installed through the elastic retaining ring and the sleeve; at the same time, a step surface is provided to cooperate with the second eccentric shaft bearing and the third eccentric shaft bearing to realize axial positioning; the planetary gear is fixedly connected to the eccentric shaft through the elastic retaining ring and the keyway, and the second bearing is pressed on the corresponding step surface of the eccentric shaft to realize the limited installation.

4. According to the novel four-phase RV reducer of claim 1, it is characterized in that: The eccentric directions of the first eccentric bearing part, the second eccentric bearing part, the third eccentric bearing part and the fourth eccentric bearing part are alternated by 90° in sequence, that is, they are evenly distributed in four phases at 90°; or the eccentric directions of the first eccentric bearing part and the fourth eccentric bearing part are alternated by 180°, and the eccentric directions of the second eccentric bearing part and the third eccentric bearing part are alternated by 180°, that is, two groups are distributed oppositely; the first cycloidal wheel, the second cycloidal wheel, the third cycloidal wheel and the fourth cycloidal wheel are respectively interference fit with the outer rings of the first eccentric shaft bearing, the second eccentric shaft bearing, the third eccentric shaft bearing and the fourth eccentric shaft bearing to achieve a rotational connection with the eccentric shaft assembly and axial positioning; the first cycloidal wheel, the second cycloidal wheel, the third cycloidal wheel and the fourth cycloidal wheel are respectively meshed with the pinion housing and its needle roller.

5. According to the novel four-phase RV reducer of claim 1, it is characterized in that: The needle gear housing assembly also includes a housing end cover; the needle gear housing is provided with an arc groove for rotatably installing a needle roller, and a needle roller positioning step with an annular gasket installed, and grooves are provided on both sides of the arc groove to install an elastic retaining ring for axially positioning the annular gasket; the inner wall surface of the needle gear housing is provided with a first needle gear housing step and a second needle gear housing step, and the output end cover is provided with a stopper to press the first needle gear housing bearing onto the first needle gear housing step to achieve axial positioning; the second needle gear housing bearing is pressed onto the second needle gear housing step by the planetary carrier to achieve axial positioning.

6. According to the novel four-phase RV reducer of claim 1, it is characterized in that: The output shaft assembly is rotatably installed in the pinion housing assembly through the first pinion housing bearing and the second pinion housing bearing; the output end cover is fixedly connected to the planetary carrier by screws, one end of the output shaft is fixedly connected to the planetary carrier, and the other end is provided with an output shaft keyway for the speed and torque output of the reducer; the output end cover and the planetary carrier respectively press the inner rings of the first pinion housing bearing and the second pinion housing bearing to achieve axial positioning.

7. According to claim 1, a novel four-phase RV reducer is characterized in that: The input shaft is rotatably mounted on the output end cover and the planet carrier through a first input shaft bearing and a second input shaft bearing respectively; the input shaft is axially positioned with the first input shaft bearing and the second input shaft bearing through interference fit or through a shoulder arranged on the input shaft.

8. According to the novel four-phase RV reducer of claim 1, it is characterized in that: The number of eccentric shaft assemblies uniformly distributed around the circumference is three or more; one end of each of the eccentric shafts is rotatably mounted on the output end cover via a first bearing; the other end of each of the eccentric shafts is rotatably mounted on the planet carrier via a second bearing.

9. A working method of a novel four-phase RV reducer according to any one of claims 1 to 8, characterized in that: The steps include: The motor transmits power to the input shaft, which meshes with the sun gear and the planetary gear to form the first stage reduction part; the planetary gear rotates to drive the eccentric shaft to rotate, and the force of the eccentric shaft is transmitted to the needle roller on the pinion housing through the eccentric shaft bearing and the four cycloid wheels, and then the reaction force of the needle roller drives the four cycloid wheels to rotate in the opposite direction, thereby driving the eccentric shaft to revolve around the central axis of the input shaft; the eccentric shaft drives the output end cover and the planetary carrier to revolve around the central axis of the input shaft through the first bearing and the second bearing respectively, and the output shaft and the output end cover are fixedly connected to the planetary carrier, so that the three rotate in the opposite direction around the center line of the input shaft together, realizing the second stage reduction, thereby realizing high reduction ratio transmission.

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