阅读说明：本技术 工业机器人内啮合rv减速机 (Industrial robot inner gearing RV speed reducer ) 是由 李响 刘巍巍 刘谷华 于 2020-06-22 设计创作，主要内容包括：本发明公开了一种工业机器人内啮合RV减速机,对摆线轮修形后,对摆线轮修形后,使得内摆线齿与摆线轮齿槽间产生合理间隙(径隙Δj与侧隙Δc),使减速机在额定负载下,摆线轮热膨胀时啮合件不被卡死,而且采用了凹-凸啮合,还可以大大简化内摆线齿圈结构。(The invention discloses an industrial robot inner gearing RV speed reducer, which is characterized in that after a cycloid wheel is shaped, a reasonable gap (a radial gap delta j and a side gap delta c) is generated between an inner cycloid tooth and a cycloid wheel tooth groove after the cycloid wheel is shaped, so that a meshing part of the speed reducer is not clamped when the cycloid wheel is thermally expanded under a rated load, concave-convex meshing is adopted, and the structure of an inner cycloid gear ring can be greatly simplified.)

1. An industrial robot inner gearing RV speed reducer, comprising: hypocycloid gear ring and arrange two-stage reduction part in it: the first-stage speed reduction part comprises an input shaft, a sun gear and a planet gear; the second-stage speed reduction component comprises 2-3 eccentric shafts, cycloidal gears and a planet carrier which are uniformly distributed, each cycloidal gear comprises a first cycloidal gear and a second cycloidal gear, the planet carrier comprises a left side planetary disk and a right side planetary disk, the extending end of each eccentric shaft is connected with a planetary gear, eccentric shaft bearings used for supporting the cycloidal gears are arranged on two eccentric sections of the eccentric shafts, the shaft extensions on two sides of the eccentric sections of the eccentric shafts are respectively supported in peripheral holes of the left side planetary disk and the right side planetary disk through conical roller shafts, the left side planetary disk and the right side planetary disk are respectively supported in inner holes on two sides of an inner cycloidal gear ring through main bearings, the input shafts are respectively supported in central holes of the left side planetary disk and the right side planetary disk through corresponding holes of the cycloidal gears, and flanges uniformly distributed on the left side planetary disk pass through corresponding holes of the cycloidal gears to be connected with positioning pins:

(A) the cycloid gear must be trimmed and a reasonable radial clearance delta j must be generated between hypocycloid teeth and cycloid tooth grooves so as to

Under the rated torque, the thermal expansion of the cycloid wheel does not cause the meshing part to be in interference friction, so the radial clearance delta j is necessarily related to the thermal expansion amount omega:

radial gap Δ j = (0.18 ~ 0.5) Ω

Cycloid gear thermal expansion amount omega = (α)_t·Δt）d0

In the formula: temperature rise delta t =45 ℃, and d0 is the average diameter of the addendum circle and the dedendum circle of the cycloidal gear;

(B) the cycloid wheel adopts a positive equal distance-positive displacement combined modification, and the modification amount depends on a radial clearance delta j:

positive equidistance modification quantity delta r_z= delta j/(1-K), positive displacement modification amount delta R_z=K Δr_zIn the formula:

K=（1-K₁ ²）^0.5short amplitude coefficient K₁=eZ_bZ, e-eccentricity, Z_b-the number of teeth, Rz-the centre circle radius of the teeth;

(C) the positive equidistant modification quantity delta Rz and the positive displacement delta Rz determine the size of a backlash delta c, the backlash delta c represents the size of return difference, and in order to eliminate the return difference, according to the principle of an anti-backlash gear, the phase difference delta psi of two eccentric sections of the eccentric shaft cannot be equal to 180 degrees in the background technology: the first eccentric section deviates from the tiny angle theta to enable the cycloid wheel to be close to the hypocycloid tooth clockwise; and the second eccentric section is reversely deviated from a slight angle theta to enable the other cycloidal gear to be close to the hypocycloid teeth anticlockwise, and the phase difference delta psi = 180-2 theta or delta psi < 179 DEG is formed between the two eccentric sections so as to reduce or eliminate return difference.

2. An industrial robot inner gearing RV reducer according to claim 1, characterized in that: and a radial clearance delta j = (0.183-0.4) omega between the hypocycloid gear ring and the cycloidal gear tooth groove.

3. The industrial robot RV reducer of claim 2, characterized in that: the radial clearance delta j between the hypocycloid gear ring and the cycloidal gear tooth groove is as follows: delta j is more than or equal to 0.186 omega and less than or equal to 0.3 omega.

4. An industrial robot inner gearing RV reducer according to claim 1, characterized in that: corresponding to the size of the side clearance delta c value of the RV model, according to the principle of the anti-backlash gear, the phase difference of two eccentric sections of the eccentric shaft is as follows: Δ Ψ =177.7 ° -178.9 °.

5. An industrial robot inner gearing RV reducer according to claim 4, characterized in that: and (3) corresponding to the size of the side clearance delta c value of the RV model, and according to the principle of the backlash eliminating gear, the phase difference of two eccentric sections of the eccentric shaft is as follows: 177.8 degrees and less than or equal to delta psi and less than or equal to 178.8 degrees.

6. An industrial robot inner gearing RV reducer according to claim 2, characterized in that: and (3) corresponding to the size of the side clearance delta c value of the RV model, and according to the principle of the backlash eliminating gear, the phase difference of two eccentric sections of the eccentric shaft is as follows: Δ Ψ =177.7 ° -178.9 °.

7. An industrial robot inner gearing RV reducer according to claim 6, characterized in that: and (3) corresponding to the size of the side clearance delta c value of the RV model, and according to the principle of the backlash eliminating gear, the phase difference of two eccentric sections of the eccentric shaft is as follows: 177.8 degrees and less than or equal to delta psi and less than or equal to 178.8 degrees.

8. An industrial robot inner gearing RV reducer according to claim 3, characterized in that: and (3) corresponding to the size of the side clearance delta c value of the RV model, and according to the principle of the backlash eliminating gear, the phase difference of two eccentric sections of the eccentric shaft is as follows: Δ Ψ =177.7 ° -178.9 °.

9. An industrial robot inner gearing RV reducer according to claim 8, characterized in that: and (3) corresponding to the size of the side clearance delta c value of the RV model, and according to the principle of the backlash eliminating gear, the phase difference of two eccentric sections of the eccentric shaft is as follows: 177.8 degrees and less than or equal to delta psi and less than or equal to 178.8 degrees.

10. An inner gearing RV reducer for an industrial robot according to any of claims 1-9, characterized in that the coefficient of thermal expansion of the cycloidal bearing steel is α t = 1.379-10^-5(1/° c), Ω = (α t · Δ t) d0=0.00062 · d0, with units of Δ j and Ω being mm.

Technical Field

The invention relates to the technical field of speed reducers of industrial robots, in particular to an internal gearing RV speed reducer of an industrial robot, which solves the defects of heating and short service life in the background technology by using a thermal expansion theory and has good dynamic characteristics.

Background

2019, 9 and 18, and professor Zhangming professor of first place scientists of Beijing Zhi classmate: the biggest difference between the domestic speed reducer and the Japanese Nabo Tesch speed reducer lies in the precision retentivity and the service life.

11/23/2019, inventor 2019111606018, mardish corporation in ningbo: the invention relates to a cycloidal pin wheel transmission structure, which is used for solving the problem that the RV transmission precision is not ideal in China at the present stage.

12 and 17 th 2019, the point out in localization of the innovative driving technology source-Yi bow science boosting RV reducer is that: "domestic RV reducer is developed for several years, but still faces the pain point: high heat generation, high noise, insufficient rigidity, and insufficient accuracy retention. "

It is shown that the domestic RV reducer is still a big gap from Japan Nabo by the end of 2019, and the reason analysis is as follows:

the national researchers lack the theoretical research on the reasonable meshing clearance of the shape modification of the cycloid wheel

The manual for designing gear transmission 804 notes that: the reasonable modification of the tooth profile of the cycloid wheel can meet the following requirements:

a. reasonable meshing side clearance and radial clearance can be formed, actual manufacturing and mounting errors can be compensated, and enough meshing tooth number can be ensured; b. the working part of the tooth form should approach the conjugate tooth form to the maximum extent to make the transmission stable; c. the grinding process is simple.

Both theory and practice prove that the ideal tooth form can be obtained by adopting a positive equal distance-positive displacement optimized combination shape modification method.

When the cycloidal gear is ground by regular equidistant profile modification, the arc radius (equivalent to the tooth profile radius of a needle tooth) of the grinding wheel is increased from the standard rz to rz + delta rz; the positive displacement distance modification is to move the grinding wheel a slight distance Δ Rz away from the table center, that is, to increase the pin tooth center radius Rz to Rz + Δ Rz during grinding. "

The cable picking literature indicates that no research on theoretical values of the side gap and the radial gap of the shape modification of the cycloid gear is found at home;

(II) the reasonable meshing clearance clarified by physics is closely related to the thermal expansion quantity of the cycloid wheel

Northern university of industry "RV reducer thermal-structural coupling analysis": "domestic research on RV reduction gear heat-structure coupling is less, but reduction gear uses grease lubrication, and the heat dissipation condition is not good, and various conditions are closely related to heat in operation. The influence of temperature on the volume of the part is considered so as to avoid the blocking due to the over-temperature expansion. "(2016.06)

Researchers have few researches on the aspect of heat-structure coupling of the RV reducer, various conditions in operation are closely related to heat, a cycloidal gear is a main source of heat, and the cycloidal gear is inevitably blocked due to overhigh temperature when the gap is too small. The thermal expansion of the cycloid gears was analyzed as follows:

the physics explains that the expansion law of the solid is the same in all directions, so the linear expansion law of the solid in one direction can be used for representing the expansion of the solid, namely: the linear expansion coefficient α t = (d-d 0)/(d0 Δ t) = Ω/(d0 · Δ t), so:

thermal expansion amount Ω = (α t · Δ t) d 0;

(III) domestic researchers consider that the eccentric shaft phase difference delta psi =180 DEG, so that only negative displacement-negative equidistant modification can be adopted

The cable is found, domestic researchers identify that the RV reducer eccentric shaft phase difference is =180 degrees, and the following table shows a small part of more than 80 documents

However, theoretical calculations prove that negative isometric-negative shift-distance combined modification has a consistent and striking characteristic: the backlash Δ C is too small, and thus not only thermal expansion and manufacturing errors due to temperature rise cannot be compensated for, but also seizure due to temperature rise expansion cannot be avoided. The following are exemplified:

(example 1) 2017.04 Daidan-Merry-Convergence research on meshing stiffness of cycloidal gears … driven by … RV: RZ =77, e =1.50, Za =39, K₁= -0.022, Δ RZ = -0.027: backlash Δ c =0.003 (mm) (too small);

(example 2) design research on medium and small power shell fixed RV-E reducer of Haohang size RV-450E: RZ =155, e =3.0, Za =37, K₁=0.7355, Δ RZ = -0.015, Δ RZ = -0.03, backlash Δ c =0.007 (mm) (too small);

(example 3) college x professor "research on tooth clearance of high-precision RV reducer based on …" parameters RV-40E: RZ =64,

e=1.30、Za=39；K₁= 0.8125, Δ RZ = -0.002, Δ RZ = -0.008, and backlash Δ c =0.003 (mm) (too small).

In addition, the conventional RV-E type speed reducer pinwheel (pointer gear shell and semi-buried pinpin) has the following problems:

(1) the problem that a harmonic reducer with poor rigidity can not be replaced by a smaller machine type than the RV-6E cannot be manufactured because the small machine type pin wheel is difficult to manufacture, and a paper 'RV reducer motion precision error factor and high motion precision process guarantee' indicates that: "RV speed reducer pin gear shell half-buried hole is a group of semicircle holes with very small radius size and very high precision requirement, the processing technology of the high-precision small semicircle hole with large length-diameter ratio has very great difficulty under the conventional production condition, …";

(2) the RV-E type pin wheel-cycloid gear train convex-convex meshing is larger than the concave-concave meshing of double cycloid transmission in equivalent radius, so that the bearing capacity is lower than that of the concave-concave double cycloid transmission, and in addition, the pin and the semi-buried hole are poor in lubrication and are in sliding friction, so that the semi-buried hole is easily abraded, and the return difference is increased.

Shenpeji, Li implantable "double cycloid gear reducer" points out: the double cycloid gear speed reducer makes a breakthrough from the meshing principle, utilizes a pair of full-envelope cycloid gears as a gear mechanism of a conjugate curve, and adopts different forms of one-tooth-difference planetary gear transmission to realize speed reduction, thereby greatly simplifying the structure and the process.

Disclosure of Invention

The invention aims to solve the defects of heating and short service life of the background technology by using a thermal expansion theory and an anti-backlash cycloid, and provides an industrial robot RV reducer which has good dynamic characteristics and can be interchanged with Japanese Nabo Tesch products.

In order to solve the technical problems, the invention adopts the following technical characteristics:

the utility model provides an industrial robot inner gearing RV speed reducer, including hypocycloid ring gear and arrange the two-stage speed reduction part wherein in: the first stage comprises an input shaft, a sun gear and a planet gear; the second level includes the eccentric shaft of equipartition, cycloid wheel, bearing and planet carrier, wherein: the cycloidal gear comprises a first cycloidal gear and a second cycloidal gear, the planet carrier comprises a left side planet disk and a right side planet disk, the extension end of an eccentric shaft is connected with a planet wheel, eccentric shaft bearings for supporting the cycloidal gear are arranged on two eccentric sections of the eccentric shaft, the shaft extensions on the two sides of the eccentric section of the eccentric shaft are respectively supported in peripheral holes of the left side planet disk and the right side planet disk by tapered roller bearings, the left side planet disk and the right side planet disk are respectively supported on two sides of an inner cycloidal gear ring by main bearings, an input shaft is respectively supported in central holes of the left side planet disk and the right side planet disk by an input bearing, a flange on the left side planet disk penetrates through a corresponding hole of the cycloidal gear to:

(A) the reasonable radial clearance delta j is generated between the hypocycloid teeth and the cycloidal tooth grooves to ensure that the thermal expansion of the cycloidal gear does not cause the meshing part to be in interference friction under the rated torque, so the reasonable radial clearance delta j is necessarily related to the thermal expansion omega:

a radial gap Δ j = (0.18 to 0.5) Ω,

thermal expansion amount Ω = (α t · Δ t) d0,

wherein the temperature rise delta t =45 ℃, d0 is the average diameter of the addendum circle and the dedendum circle of the cycloidal gear, and the coefficient of thermal expansion of the cycloidal gear bearing steel is α_t=1.379·10^-5(1/° c), Ω = (α t · Δ t) d0=0.00062 · d0, units of Δ j and Ω being mm;

(B) the cycloid wheel adopts a positive equal distance-positive displacement combined modification, and the modification amount depends on a radial clearance delta j:

positive equidistance modification quantity delta r_z= Δ j/(1-K), positive displacement modification amount Δ R_z=KΔr_z，Δr_z-ΔR_z= Δ j, where:

K=（1-K₁ ²）^0.5short amplitude coefficient K₁=e Z_bZ/Rz, e is the eccentricity, Z_bNumber of teeth of the needle, R_zIs the radius of the central circle of the needle teeth,

(C) determining the size of a side clearance delta c by the positive equidistant modification quantity delta Rz and the positive displacement modification quantity delta Rz, wherein the side clearance delta c represents the return difference size, and according to the principle of a backlash eliminating gear, a first eccentric section of an eccentric shaft of the RV speed reducer deviates from a tiny angle theta to enable one cycloidal gear to be close to hypocycloid teeth clockwise; and the second eccentric section deviates reversely by a slight angle theta to enable the other cycloidal gear to approach to the hypocycloidal tooth anticlockwise, and the phase difference delta psi = 180-2 theta or delta psi < 179 DEG is formed between the two eccentric sections of the RV reducer eccentric shaft so as to reduce or eliminate the return difference.

In a preferred embodiment of the present invention, the radial gap Δ j = (0.205-0.4) Ω between the hypocycloidal tooth and the cycloidal tooth slot.

In a preferred embodiment of the invention, the radial gap Δ j between the hypocycloidal tooth and the cycloidal tooth slot is: delta j is more than or equal to 0.21 omega and less than or equal to 0.3 omega.

In a preferred embodiment of the invention, corresponding to the side clearance delta c values of various RV models, the phase difference delta psi of the eccentric shaft two eccentric sections is = 177.7-178.9 degrees according to the principle of an anti-backlash gear.

In a preferred embodiment of the invention, corresponding to the side clearance delta c values of various RV models, according to the principle of anti-backlash gears, the phase difference of two eccentric sections of the eccentric shaft is as follows: 177.8 degrees and less than or equal to delta psi and less than or equal to 178.8 degrees.

The invention has the beneficial effects that: after the shape of the cycloidal gear is modified, a reasonable gap (a radial gap delta j and a side gap delta c) is formed between an inner cycloidal tooth and a cycloidal gear tooth groove, so that a meshing part is not blocked when the cycloidal gear is thermally expanded under a rated load of the speed reducer.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein: FIG. 1 is a schematic cross-sectional view of a preferred embodiment of the present invention;

in the figure: 1. the planetary gear set comprises a hypocycloid gear ring, 2 parts of a main bearing, 3 parts of a first cycloidal gear, 4 parts of planet gears, 5 parts of a second cycloidal gear, 6 parts of an eccentric shaft, 7 parts of a tapered roller bearing, 8 parts of an eccentric shaft bearing, 9 parts of an input shaft, 10 parts of an input shaft bearing, 11 parts of a left side planetary disk flange, 12 parts of a right side planetary disk, 13 parts of a left side planetary disk and 14 parts of a sun gear.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, an embodiment of the present invention includes:

an industrial robot RV speed reducer adopts a Japanese Nabo RV structure so as to be convenient for exchange with the same, and the specific structure comprises a hypocycloid gear ring 1 and two-stage speed reducing components arranged in the hypocycloid gear ring: the first-stage speed reduction part comprises an input shaft 9, a sun gear 14 and a planet gear 4; the second-stage speed reduction component comprises 2-3 eccentric shafts 8, cycloidal gears and a planet carrier which are uniformly distributed, the cycloidal gears comprise a first cycloidal gear 3 and a second cycloidal gear 5, the planet carrier comprises a left side planet disk 13 and a right side planet disk 12, the shaft extension end of the eccentric shaft 6 is connected with a planet wheel 15, the eccentric shaft bearings 8 for supporting the cycloid wheel are arranged on the two eccentric sections of the eccentric shaft 6, the shaft extensions on the two sides of the eccentric section of the eccentric shaft are respectively supported in the peripheral holes of the left planetary disk 13 and the right planetary disk 12 by tapered roller bearings 7, the left side planetary disk 13 and the right side planetary disk 12 are respectively supported in the inner holes at the two sides of the hypocycloid gear ring 1 by the main bearing 2, the input shaft 9 is supported in the central holes of a left planetary disk 13 and a right planetary disk 12 by an input shaft bearing 10 respectively, and the flanges 11 uniformly distributed on the left planetary plate 13 penetrate through corresponding holes of the cycloid wheel to be connected with the right planetary plate 12 into a rigid body by using screws and positioning pins.

A cycloidal gear of an industrial robot inner gearing RV reducer must be shaped:

(A) when the shape of the cycloid wheel is modified, a reasonable radial gap delta j needs to be generated between hypocycloid teeth and cycloid tooth grooves to ensure that under rated torque, the meshing parts are not in interference friction due to thermal expansion of the cycloid wheel, and therefore the reasonable radial gap delta j is necessarily related to thermal expansion omega.

The explanation of physics, the expansion law of solid is the same in all directions, namely the linear expansion law of solid in one direction can be used to represent the solid expansion: α t = (d-d 0)/(d0 Δ t) = Ω/(d0 · Δ t), so:

since the cycloid wheel thermal expansion amount Ω = (α t · Δ t) d0, there are:

Δj =（0.18～0.5）Ω（mm），

thermal expansion amount Ω = (α t · Δ t }) d0=0.00062 · d0 (mm).

D 0-mean diameter of addendum circle and dedendum circle of cycloidal gear, coefficient of thermal expansion α t = 1.379-10 of bearing steel^-5(1/° c), these data, although possibly variable, can be measured by current technical means with a temperature rise Δ t =45 ℃.

Further, a radial gap Δ j = (0.183 to 0.4) Ω between the hypocycloidal tooth and the cycloidal gear tooth groove.

Further, the radial clearance Δ j between the hypocycloidal teeth and the trochoid spline: delta j is more than or equal to 0.186 omega and less than or equal to 0.3 omega (mm), and the radial clearance of the cycloid wheel can be more accurately controlled.

(B) The cycloid wheel adopts a positive equal distance-positive displacement combined modification, and the modification amount depends on a radial clearance delta j:

Δr_z=Δj/（1－K）、 ΔR_z=K Δr_zand Δ Rz- Δ Rz = Δ j (mm), wherein:

K=（1-K₁ ²）^0.5coefficient of shortwave K₁=eZ_bZ/Rz, e is the eccentricity, Z_bAnd Rz is the central circle radius of the pin teeth.

The acting force between the teeth of the positive equidistant-positive displacement modification and the teeth of the hypocycloid is 49 percent of that of the negative equidistant-negative displacement modification; the bearing capacity of the positive equidistant-positive displacement modification is 1.71 times that of the negative equidistant-negative displacement modification. (& ltPin pendulum gearing tooth form optimization and dynamic return error analysis) & gt

Equidistant modification: the grinding radius of the grinding wheel is increased to be a positive equal distance; otherwise, the distance is reduced to negative equidistance;

moving distance and modifying: the grinding wheel deviates from the center of the workbench by a positive displacement distance; otherwise, the shift-in is a negative shift distance.

(C) The positive equidistant modification quantity delta Rz and the positive displacement modification quantity delta Rz determine the value of a backlash delta c, the value of the backlash delta c represents the return difference, and in order to eliminate the return difference, according to the principle of a backlash eliminating gear, the phase difference of two eccentric sections of the eccentric shaft cannot be equal to 180 degrees: the first eccentric section deviates from the tiny angle theta to enable the cycloid wheel to be close to the hypocycloid tooth clockwise; and the second eccentric section is reversely deviated from a slight angle theta to enable the other cycloidal gear to be close to the hypocycloid teeth anticlockwise, and the phase difference delta psi = 180-2 theta or delta psi < 179 DEG is formed between the two eccentric sections so as to reduce or eliminate return difference.

The value of the side clearance delta c is related to factors such as adjacent distance deviation of hypocycloid teeth, tooth distance deviation of cycloidal gears, assembly deviation and the like and the model number of the RV. When the side clearance delta c is too small, the thermal expansion of the cycloidal gears leads the parts to be in interference friction, thus increasing the noise, wearing, vibrating and shortening the service life; the backlash Δ c is too large, and vibration is likely to occur when the input rotation speed is too high.

The principle of anti-backlash gears is described in doctor's paper "anti-backlash gear system … and its dynamic performance impact research":

"rely on the method that improves the machining precision to guarantee the transmission precision, will increase the processing cost by a wide margin. … should employ effective backlash elimination to control transmission errors and improve the transmission accuracy of the mechanism, … ".

The spring-loaded double-piece gear backlash eliminating mechanism (abbreviated as backlash eliminating gear) can eliminate backlash caused by gear manufacturing errors and idle stroke caused by temperature change, and is widely applied to industrial robots, precision servo mechanisms, radar antennas and inertially stabilized platforms. Inertial Stabilization Platforms (ISPs) for mobile carrier systems such as satellites, missiles, etc.

The anti-backlash gear mechanism not only requires to have the dynamic characteristics of high speed, high precision and high stability, but also has larger working condition change when the gear system works in the load environment of frequent starting, braking and positive and negative rotation. "

Furthermore, according to the anti-backlash gear principle, corresponding to the side clearance delta c values of various models,

the phase difference delta psi of the eccentric shaft two eccentric sections is = 177.7-178.9 deg.

Furthermore, the side clearance delta c value corresponding to various models can be obtained according to the principle of the anti-backlash gear,

phase difference of two eccentric sections of the eccentric shaft: 177.8 degrees and less than or equal to delta psi and less than or equal to 178.8 degrees.

The phase difference delta psi of the two eccentric sections of the eccentric shaft is not equal to 180 degrees, so that the backlash eliminating gear is formed like a backlash eliminating gear of a high-precision numerical control machine tool, and the backlash eliminating cycloid gear structure has the effect of eliminating return difference and requires that the precision of shape modification is far lower than 0.001 (mm) of RV-250 AII.

Theoretical calculation confirms that the phase difference of the eccentric sections is as follows: at 177.8 DEG & lt, & gt, Δ psi & lt, 178.8 DEG, the unbalanced centrifugal force is small because the deflection of the eccentric section clockwise and counterclockwise around the center of mass of the rotor (i.e., the eccentric section) is in the shape of a thin crescent, with very small mass, as shown in the following table:

further calculations confirm that the phase difference of the eccentric sections: when the angle is 177.8 degrees and less than or equal to delta psi and less than or equal to 178.8 degrees, the maximum allowable unbalance degree reaches G1 level. The balance quality is grade 11: g0.4 stage, G1 stage, G2.5 stage, G6.3 stage … …, G1600 stage, and G4000 stage.

Taking RV-80E as an example: the mass m =192 (g) and the rotating speed n =1000rpm of the two eccentric sections,

allowable unbalance eper =1.0 (60 · 10)³/2π·1000）= 9.55（g·mm/kg），

Allowable unbalance amount up = m · eper = (192/1000) · 9.55=1.834 · 10³（g·mm），

Uper Ⅰ=1.834·10³（0.5L/L）=0.917·10³（g·mm），UpeⅡ= Uper Ⅰ，

Thus, Uper I + Upe II = 0.917.10³+0.917·10³=1.834·10³（g·mm）。

The industrial robot inner gearing RV reducer has the beneficial effects that:

(1) after the shape of the cycloidal gear is modified, a reasonable gap (a radial gap delta j and a side gap delta c) is generated between the pin and the tooth socket of the cycloidal gear, so that an engaging part is not blocked when the cycloidal gear is thermally expanded under a rated load of the speed reducer;

(2) the invention can be made into a small machine type to replace a harmonic reducer, and the hypocycloid gear ring greatly simplifies the structure;

(3) the invention has concave-convex engagement, small equivalent curvature radius, larger bearing capacity than that of a cycloidal pin gear structure by 50 percent, and can forcibly form a high-pressure oil film near an engagement node, and the transmission efficiency is 5 percent higher than that of the cycloidal pin gear structure under the liquid friction lubrication state.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.