阅读说明：本技术 工业机器人rv-c型减速机 (RV-C type speed reducer of industrial robot ) 是由 刘巍巍 吴小杰 吴绍松 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RV-C型减速机,对摆线轮修形后,使得针销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,而且不需要很高的制造精度,还可以与市面上的RV减速器互换,提高产品的适应性和实用性。(The invention discloses an industrial robot RV-C type speed reducer, which can generate reasonable gaps (a radial gap delta j and a side gap delta C) between a needle pin and a tooth socket of a cycloidal gear after the cycloidal gear is shaped, so that an engaging part of the cycloidal gear is not blocked when the cycloidal gear is thermally expanded under rated load of the speed reducer, high manufacturing precision is not needed, the speed reducer can be exchanged with the RV speed reducer on the market, and the adaptability and the practicability of a product are improved.)

1. An industrial robot RV-C type speed reducer, includes the pin gear shell and arranges the two-stage speed reduction part in it: the first-stage reduction part comprises a driving wheel, a duplicate gear and a planetary gear on the servo motor, the duplicate gear comprises a driven wheel and a sun wheel, the driven wheel is meshed with the driving wheel, the sun wheel is meshed with the planetary gear, the planetary gear is connected to the extension end of an eccentric shaft of the second-stage reduction part, a through pipe is arranged in an inner hole of the duplicate gear, and two sides of the duplicate gear are respectively supported on corresponding positions of the right rigid disc and the robot body through a first bearing and a second bearing; the second-stage speed reduction component comprises 2-3 eccentric shafts, cycloidal gears, a pin, a left rigid disc and a right rigid disc which are uniformly distributed, each cycloidal gear comprises a first cycloidal gear and a second cycloidal gear, eccentric shaft bearings used for supporting the cycloidal gears are arranged on two eccentric sections of the eccentric shafts, shaft extensions on two sides of the eccentric sections are respectively supported in peripheral holes of the left rigid disc and the right rigid disc by conical roller bearings, the left rigid disc and the right rigid disc are respectively supported in inner holes on two sides of a pin gear shell by main bearings, and flanges uniformly distributed on the left rigid disc penetrate through corresponding holes in the cycloidal gears to be connected with the right rigid disc by screws and positioning pins to form a rigid body, and the second-stage speed reduction component:

(A) the cycloid wheel must be modified in shape, and a reasonable radial clearance delta j must be generated between a pin and a cycloid tooth groove to ensure that under rated torque, the thermal expansion of the cycloid wheel does not cause an engagement part to be in interference friction, so that the radial clearance delta j must be related to thermal expansion 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 pin 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 pin anticlockwise, and the phase difference delta psi of the two eccentric sections is = 180-2 theta or delta psi < 179 DEG so as to reduce or eliminate the return difference.

2. An industrial robot RV-C reducer according to claim 1 characterized in that: and a radial gap delta j = (0.183-0.4) omega between the pin and the tooth groove of the cycloidal gear.

3. An industrial robot RV-C reducer according to claim 2 characterized in that: the radial clearance delta j between the pin and the tooth groove of the cycloidal gear 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 RV-C 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 RV-C 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 RV-C 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 RV-C 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 RV-C 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 RV-C reducer according to claim 8 characterized by: 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 industrial robot RV-C reducer according to any of the claims 1-9 characterized in that the coefficient of thermal expansion of the cycloid 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 a hollow type 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.

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 heat-structure coupling of RV reducer

The speed reducer is less in grease lubrication, the heat dissipation condition is poor, and various conditions are closely related to heat in operation. Temperature is to be considered

The influence of the temperature on the volume of the part is avoided, so that the part is prevented from being blocked due to overhigh temperature and 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 small parts in more than 80 cases of documents Is divided into

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).

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 a hollow type industrial robot RV-C type speed reducer which has good dynamic characteristics and can be exchanged with a Japanese Naboteske product.

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

the utility model provides an industrial robot RV-C type speed reducer, including the pin gear shell and arrange the two-stage speed reduction part in it: the first stage comprises a driving wheel, a duplicate gear and a planet wheel on the servo motor, the duplicate gear comprises a driven wheel and a sun wheel, the driven wheel is meshed with the driving wheel, the sun wheel is meshed with the planet wheel, the planet wheel is connected to the extension end of an eccentric shaft of the second stage speed reduction part, a through pipe is arranged in an inner hole of the duplicate gear, and two sides of the duplicate gear are respectively supported on the right rigid disc and the corresponding position of the robot body through a first bearing and a second bearing; the second level includes the eccentric shaft of 2 equipartitions, the cycloid wheel, the needle, left rigidity dish and right rigidity dish, the cycloid wheel includes first cycloid wheel and second cycloid wheel, be equipped with the eccentric bearing that is used for supporting the cycloid wheel on two eccentric sections of eccentric shaft, eccentric section both sides axle is stretched and is supported in left and right rigidity dish week edge hole respectively with tapered roller bearing, left and right rigidity dish supports respectively in the needle tooth shell both sides with the base bearing, the last flange of left side rigidity dish passes corresponding hole on the cycloid wheel and connects into the rigid body with right rigidity dish, the cycloid wheel is repaiied the shape after:

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

a radial gap Δ j = (0.18-0.5) Ω (mm),

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 reducer deviates from a tiny angle theta to enable one cycloidal gear to be close to a pin 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 pin counterclockwise, and the phase difference delta psi of the two eccentric sections of the eccentric shaft of the RV reducer is = 180-2 theta or delta psi < 179 degrees so as to reduce or eliminate the return difference.

In a preferred embodiment of the invention, the radial gap Δ j = (0.183-0.4) Ω between the pin and the cycloidal tooth slot.

In a preferred embodiment of the present invention, the radial clearance Δ j between the pin and the cycloidal tooth slot is: delta j is more than or equal to 0.186 omega and less than or equal to 0.3 omega.

In a preferred embodiment of the present invention, the magnitude, root, of the backlash Δ c values for various RV models

According to the principle of the anti-backlash gear, the phase difference delta psi of the eccentric shaft two eccentric sections is 177.7-178.9 degrees.

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 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 of the cycloidal gear is not blocked when the cycloidal gear is thermally expanded under a rated load, high manufacturing precision is not needed, the cycloidal gear can be exchanged with a Japanese Nabo RV-C type speed reducer, and the adaptability and the practicability of a product are improved.

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 type planetary gear set comprises a pin gear shell, 2, a main bearing, 3, a first cycloidal gear, 4, a second cycloidal gear, 5, a right rigid disk, 6, a driven gear, 7, a sun gear, 8, a duplicate gear, 9, a second bearing, 10, a first bearing, 11, an eccentric shaft, 12, a planetary gear, 13, a driving wheel, 14, a tapered roller bearing, 15, an eccentric bearing, 16, a left rigid disk and 17, and a pin.

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 industrial robot RV-C type speed reducer includes a pin gear housing 1 and two-stage speed reducing components disposed therein: the first-stage reduction part comprises a driving wheel 13, a duplicate gear 8 and a planet wheel 12 on a servo motor, the duplicate gear 8 comprises a driven wheel 6 and a sun wheel 7, the driven wheel 6 is meshed with the driving wheel 13, the sun wheel 7 is meshed with the planet wheel 12, the planet wheel 12 is connected with the axial extension end of an eccentric shaft 11 of the second-stage reduction part, a through pipe is arranged in an inner hole of the duplicate gear 8, and two sides of the duplicate gear 8 are respectively supported on the right rigid disc 5 and the corresponding position of the robot body through a first bearing 10 and a second bearing 9; the second-stage speed reduction component comprises 2-3 eccentric shafts 11, cycloidal gears, a pin 17, a left rigid disk 16 and a right rigid disk 5 which are uniformly distributed, each cycloidal gear comprises a first cycloidal gear 3 and a second cycloidal gear 4, eccentric shaft bearings 15 used for supporting the cycloidal gears are arranged on two eccentric sections of the eccentric shafts 3, shaft extensions on two sides of the eccentric sections are respectively supported in peripheral holes of the left rigid disk 16 and the right rigid disk 5 through conical roller bearings 14, the left rigid disk 16 and the right rigid disk 5 are respectively supported in inner holes on two sides of a pin gear shell 1 through main bearings 2, and flanges uniformly distributed on the left rigid disk 16 penetrate through corresponding holes in the cycloidal gears to be connected with the right rigid disk 5 through screws and positioning pins to form a rigid body.

A cycloidal gear of an industrial robot RV-C type speed reducer must be shaped:

(A) when the shape of the cycloid wheel is modified, a reasonable radial clearance delta j needs to be generated between the pin and the cycloid tooth groove to ensure that under rated torque, the meshing part is not in interference friction due to thermal expansion of the cycloid wheel, and therefore the reasonable radial clearance 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:

a radial gap Δ j = (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 mm between the pin 4 and the trochoid spline.

Further, the radial clearance Δ j between the pin 4 and the trochoid tooth groove: delta j is more than or equal to 0.186 omega and less than or equal to 0.3 omega 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:

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 gear teeth of the positive equal distance-positive displacement modification and the pin is 49 percent of that of the negative equal distance-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

Wherein the content of the first and second substances,

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 side clearance delta c, the value of the side clearance 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 an RV reducer 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 pin 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 pin anticlockwise, and the phase difference delta psi of the two eccentric sections is = 180-2 theta or delta psi < 179 DEG so as to reduce or eliminate the return difference.

The value of the side clearance delta c is related to factors such as the precision of the adjacent distance of the pin pins, the precision of the diameter of the pin, the fit clearance of the pin pins and the semi-buried holes, the pitch deviation and the assembly deviation of the cycloid wheel and the type 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, the side clearance delta c value corresponding to various RV models can be calculated according to the principle of anti-backlash gears,

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 RV models can be obtained according to the principle of anti-backlash gears,

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 RV-C type speed reducer of the industrial robot 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 only needs to use a domestic machine tool and conventional manufacturing precision, and the processing and manufacturing difficulty is low;

(3) the external dimension of the invention is the same as the RV reducer of Japanese Nabotte Tech, thus the invention can be interchanged with the RV reducer, and the adaptability and the practicability of the product are improved.

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.