Miniature cycloidal-pin wheel speed reducer and eccentric wheel eccentricity calculation method

Abstract

The invention relates to a micro cycloidal-pin wheel speed reducer and an eccentricity calculation method of an eccentric wheel. The eccentricity calculation method of the eccentric wheel comprises the steps that the pin tooth reference diameter D1 of a cycloidal disc of the cycloidal-pin wheel speed reducer is determined according to the appearance of a harmonic speed reducer; deducing the initial range of the eccentricity DS1 of an eccentric wheel of the cycloidal-pin wheel speed reducer according to the curtate coefficient K1; wherein DS1 is equal to K1 * D1 / Z; z is the number of needle teeth; drawing a curtate epicycloid of the cycloid disc according to the curtate coefficient K1; the eccentricity DS1 corresponding to the curtate epicycloid in the initial range of the eccentricity DS1 is selected as the actual eccentricity of the eccentric wheel; machining of the cycloidal-pin wheel speed reducer is determined through design and calculation of the eccentricity of the eccentric wheel, so that when the cycloidal-pin wheel speed reducer completes transmission, the problems of transmission system resonance caused by too large eccentricity and insufficient torque caused by too small eccentricity are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of cycloid pinwheel reducers, and in particular relates to a miniature cycloid pinwheel reducer and a method for calculating the eccentricity of an eccentric wheel. Background Art

[0002] With the recent development of micro-transmission devices, harmonic reducer transmissions that originally used right-angle turns can no longer meet the high rigidity and long life requirements of closed-loop servo control in specific applications. Dual-bearing support micro-cycloid reducers are highly trusted by users because they meet the high rigidity requirements of closed-loop servo control. However, traditional dual-bearing support micro-cycloid reducers use direct-axis transmission at the input, which cannot meet the requirements of vertical transmission. Therefore, it is urgent to solve the problem of meeting both vertical transmission and closed-loop servo control requirements while maintaining the same reducer size. Summary of the Invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a miniature cycloid pinwheel reducer and an eccentricity calculation method for an eccentric wheel, so that the cycloid pinwheel reducer can complete the transmission while avoiding the problems of system resonance caused by excessive eccentricity and insufficient torque caused by too small eccentricity.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] First, the present invention provides a miniature cycloid pinwheel reducer, comprising a high-speed input mechanism, a reduction mechanism, a low-speed output mechanism and a housing, wherein the high-speed input mechanism and the low-speed output mechanism are respectively nested at both ends of the housing, and the reduction mechanism is nested in the housing and connected to the high-speed input mechanism and the low-speed output mechanism respectively, wherein the high-speed input mechanism comprises a large bevel gear and a small bevel gear, wherein the large bevel gear and the small bevel gear are vertically meshed to form a right-angle transmission, one end of the large bevel gear is drive-connected to the reduction mechanism, and one end of the small bevel gear serves as the power input end of the high-speed input mechanism.

[0006] Furthermore, the reduction mechanism includes a needle gear sleeve, a cycloid disk and a pair of eccentric wheels connected in series. The outer periphery of the pair of eccentric wheels is sleeved with a cycloid disk, the cycloid disk is sleeved in the needle gear sleeve, and one end of the pair of eccentric wheels is sleeved with a large bevel gear; the low-speed output mechanism includes a support bearing and an output shaft, a pair of support bearings are respectively nested in one end of the cycloid disk, the output shaft is nested in the support bearing, the outer periphery of the output shaft is sleeved with a needle wheel, and a gap ring support bearing is sleeved at one end of the needle wheel. There are cycloid needles arrayed on the needle wheel, and one end of the cycloid needle is inserted into one end of the cycloid disk and connected to the cycloid disk.

[0007] The present invention also provides a method for calculating the eccentricity of the eccentric wheel based on the micro-cycloid pinwheel reducer, comprising the following steps:

[0008] Step 1: Determine the pitch circle diameter D1 of the cycloid disk of the cycloid pinwheel reducer according to the external dimensions of the harmonic reducer to be replaced;

[0009] Step 2: Obtain the initial range of the eccentricity DS1 of the cycloid pinwheel reducer according to the pitch circle diameter D1 of the pinwheel; wherein DS1 = K1*D1 / Z; (1)

[0010] (1) In the formula, Z is the number of needle teeth, K1 is the short amplitude coefficient;

[0011] Step 3, draw the short-amplitude epicycloid of the cycloid disk according to the short-amplitude coefficient K1;

[0012] Step 4: Select the eccentricity DS1 corresponding to the short-amplitude epicycloid within the initial range of the eccentricity DS1 as the actual eccentricity of the eccentric wheel.

[0013] Furthermore, the short-width coefficient K1 is 0.4 to 0.8.

[0014] Furthermore, the step 3 of drawing the short-amplitude epicycloid of the cycloid disk according to the short-amplitude coefficient K1 specifically includes the following steps:

[0015] Step 301, calculating the curve coordinates of the short-amplitude epicycloid according to the short-amplitude coefficient K1;

[0016] Among them, the short-amplitude epicycloid is selected as the tooth shape of the cycloid disk, and the curve coordinates of the short-amplitude epicycloid are determined according to the standard tooth shape equation of the cycloid disk (2);

[0017]

[0018] (2)In the formula, xc and yc are the curvilinear coordinates of the short-amplitude epicycloid;

[0019] r p is the radius of the needle roller;

[0020] r rp is the outer radius of the needle tooth sleeve, in mm;

[0021] i H is the relative transmission ratio between the cycloid disk and the pinwheel, Among them, zp is the number of teeth of the cycloid disk, and zc is the number of teeth of the pinwheel;

[0022] is the rotation angle of the arm relative to the center vector of a certain needle tooth, that is, the meshing phase angle;

[0023] s is a function, indicating a is a constant;

[0024] Step 302: Draw a short-amplitude epicycloid according to the curve coordinates.

[0025] Furthermore, in step 4, the eccentricity DS1 corresponding to the short-amplitude epicycloid within the initial range of the eccentricity DS1 is selected as the actual eccentricity of the eccentric wheel, specifically:

[0026] In the initial range of the eccentricity DS1, the eccentricity DS1 corresponding to the short-amplitude epicycloid without motion interference is selected as the actual eccentricity of the eccentric wheel.

[0027] Furthermore, the step 1, determining the pitch circle diameter D1 of the cycloid disk of the cycloid pinwheel reducer according to the shape of the harmonic reducer, specifically includes the following steps:

[0028] Step 101, selecting the dimensions of the harmonic reducer to be replaced;

[0029] Step 102: Determine the outer dimensions of the cycloid reducer based on the outer dimensions of the harmonic reducer to be replaced, wherein the outer dimensions of the cycloid reducer are the same as those of the harmonic reducer to be replaced.

[0030] Step 103: Determine the diameter of the pinwheel of the cycloid pinwheel reducer according to the outer dimensions of the cycloid pinwheel reducer, and determine the pitch circle diameter D1 of the pinwheel of the cycloid disk according to the pinwheel diameter and the reduction ratio of the reducer.

[0031] The present invention adopts the above technical solution, which has the following advantages and effects:

[0032] The present invention provides a method for calculating the eccentricity of a micro-cycloid pinwheel reducer and an eccentric wheel, and determines the processing of the cycloid pinwheel reducer through design calculation of the eccentricity of the eccentric wheel, so that the cycloid pinwheel reducer can avoid the problems of system resonance caused by excessive eccentricity and insufficient torque caused by excessive eccentricity while completing transmission; at the same time, because the cycloid pinwheel reducer has the same size as the harmonic reducer, a right-angle turn structural transmission is achieved through a pair of meshing bevel gears, and has the characteristics of compact structure, high transmission efficiency, large transmission ratio, long service life and high rigidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a structural schematic diagram of a micro cycloid pinwheel reducer of the present invention.

[0034] Figure 2 This is a simulation diagram of the short-amplitude epicycloid calculation of the eccentricity of the embodiment.

[0035] Figure 3 This is a frequency sweep diagram of the micro cycloid pinwheel reducer of the embodiment at 2 degrees and 25HZ.

[0036] Figure 4 This is a frequency sweep diagram of the micro cycloid pinwheel reducer of the embodiment at 3 degrees and 22HZ.

[0037] The reference numerals are as follows: 1-housing, 2-small bevel gear, 3-large bevel gear, 4-pin gear sleeve, 5-cycloid disk, 6-eccentric wheel, 7-output shaft, 8-support bearing, 9-pin wheel. DETAILED DESCRIPTION

[0038] The following will be described in detail with reference to the accompanying drawings to provide a clearer understanding of the objectives, features and advantages of the present invention. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0039] like Figure 1 The present invention provides a micro-cycloid reducer, comprising a housing 1, a high-speed input mechanism, a reduction mechanism, and a low-speed output mechanism. The high-speed input mechanism and the low-speed output mechanism are respectively nested at opposite ends of the housing 1. The reduction mechanism is nested within the housing 1 and connected to the high-speed input mechanism and the low-speed output mechanism, respectively. The high-speed input mechanism comprises a large bevel gear 3 and a small bevel gear 2, which mesh perpendicularly with each other to form a right-angle transmission. One end of the large bevel gear 3 is drivingly connected to the reduction mechanism, while one end of the small bevel gear 2 serves as the power input.

[0040] Specifically, one end of the high-speed input mechanism is connected to one end of the reduction mechanism, outputting a high rotational speed to drive the reduction mechanism. One end of the low-speed output mechanism is connected to the other end of the reduction mechanism. The reduction mechanism is used to reduce the high rotational speed of the high-speed input mechanism and transmit it to the output through the low-speed output mechanism. The reduction mechanism includes a pinion gear sleeve 4, a cycloid disk 5, and a pair of serially connected eccentrics 6. The cycloid disk 5 is sleeved around the outer periphery of each pair of eccentrics 6, which is encircled within the pinion gear sleeve 4. The large bevel gear 3 is sleeved on one end of the eccentrics 6. The low-speed output mechanism includes a support bearing 8 and an output shaft 7. The pair of support bearings 8 are respectively nested at one end of the cycloid disk 5. The output shaft 7 is nested within the support bearing 8. The outer periphery of the output shaft 7 is sleeved with a pinwheel 9, one end of which is interposed around the support bearing 8. The pinwheel 9 is arrayed with cycloid pins, one end of which is inserted into one end of the cycloid disk 5 and connected to the cycloid disk. When the high-speed input mechanism is driven, the small bevel gear 2 is installed on the motor, which drives the large bevel gear 3 to rotate. The large bevel gear 3 is fixedly connected to the eccentric wheel 6, forcing the cycloid disk 5 and the pin gear sleeve 4 to produce staggered tooth motion, thereby realizing a small tooth difference deceleration motion and achieving the deceleration purpose.

[0041] The present invention also provides a method for calculating the eccentricity of an eccentric wheel of a micro-cycloid pinwheel reducer, comprising the following steps:

[0042] Step 1: Determine the pitch circle diameter D1 of the pin teeth of the cycloid pinwheel reducer according to the external dimensions of the harmonic reducer to be replaced.

[0043] Specifically, the dimensions of the harmonic reducer to be replaced are selected. Based on the dimensions of the harmonic reducer, while maintaining the same dimensions as the cycloid reducer, the diameter of the cycloid reducer's pinwheel is determined. Furthermore, the pitch circle diameter D1 of the cycloid disk of the cycloid reducer is determined based on the pinwheel diameter and the reduction ratio of the reducer. This diameter D1 ensures that it meets the required mounting interface layout.

[0044] Step 2: Obtain the initial range of the eccentricity DS1 of the eccentric wheel of the cycloid pinwheel reducer according to the pinwheel pitch circle diameter D1.

[0045] Specifically, the eccentricity DS1 of the eccentric wheel of the cycloid reducer is derived according to the definition of the short-width coefficient in the mechanical design manual. DS1=K1*D1 / Z;(1)

[0046] (1) Where D1 is the pitch circle diameter of the needle teeth, Z is the number of needle teeth, and the short-width coefficient K1 is 0.4 to 0.8. The initial range of the eccentricity DS1 is determined based on the short-width coefficient K1.

[0047] Step 3: Draw the short-amplitude epicycloid of the cycloid disk according to the short-amplitude coefficient K1.

[0048] Specifically, a short-amplitude epicycloid K1 with a short-amplitude coefficient K1 in the range of 0.4 to 0.8 is plotted, and a suitable eccentricity DS1 of the cam is selected based on the short-amplitude epicycloid K1 to meet the transmission requirements.

[0049] The steps for drawing a short epicycloid are as follows:

[0050] First, according to the principle of cycloid pinwheel small tooth difference transmission, a short-amplitude epicycloid is selected as the tooth profile of the cycloid disk. The curve of the short-amplitude epicycloid is determined according to the standard tooth profile equation of the cycloid disk.

[0051]

[0052] (2)In the formula, xc and yc are the curvilinear coordinates of the short-amplitude epicycloid;

[0053] r p is the needle roller radius of the reducer;

[0054] r rp The outer radius of the pin gear sleeve of the reducer, in mm;

[0055] i H is the relative transmission ratio between the cycloid disk and the pinwheel, Among them, zp is the number of teeth of the cycloid disk, and zc is the number of teeth of the pinwheel;

[0056] is the rotation angle of the arm relative to the center vector of a certain needle tooth, that is, the meshing phase angle;

[0057] s is a function, indicating in, a is a constant.

[0058] Second, use MATLAB software to calculate the curve coordinates of the short-amplitude epicycloid according to formula (2), and obtain the curve coordinates of the short-amplitude epicycloid with a phase angle of 1 degree every -180° to +180°. Then, draw the short-amplitude epicycloid in CAD software based on the curve coordinates.

[0059] Step 4: Select the eccentricity DS1 corresponding to the short-amplitude epicycloid within the initial range of the eccentricity DS1 as the actual eccentricity of the eccentric wheel.

[0060] Specifically, through simulation operations, the eccentricity DS1 corresponding to the short-width epicycloid without motion interference is selected as the actual eccentricity of the eccentric wheel. The actual eccentricity of the eccentric wheel is used as the processing parameter, and the internal parts of the cycloid pinwheel reducer can be processed in sequence.

[0061] Example

[0062] Taking the 25-type harmonic reducer as an example, a cycloid pinwheel reducer with the same external dimensions is processed and manufactured.

[0063] First, the overall dimensions of the 25 model harmonic reducer are 34x34mm. Under the premise of ensuring that the shape of the cycloid pinwheel reducer remains unchanged, the diameter of the pinwheel of the cycloid pinwheel reducer is determined to be 2mm and the number of pin teeth is 42. At this time, the pitch circle diameter D1 of the cycloid pinwheel pin teeth is simulated and designed to be 29.2mm, which can meet the layout of the required installation interface.

[0064] Second, substitute D1 as 29.2 mm, Z as 42, and short amplitude coefficient K1 as 0.4 to 0.8 into formula (1), and the initial range of eccentricity DS1 is obtained as: 0.278-0.556 mm.

[0065] Third, use MATLAB software to calculate the curve coordinates of the short-amplitude epicycloid with the short-amplitude coefficient K1 in the range of 0.4 to 0.8 according to formula (2), and obtain the curve coordinates of the short-amplitude epicycloid with the phase angle in the range of -180° to +180° every 1 degree. Then, draw the short-amplitude epicycloid in CAD software according to the curve coordinates, as shown in the following example: Figure 2 shown.

[0066] Fourth, according to the short-amplitude epicycloid, an eccentric wheel is selected that is easy to manufacture and process and does not cause motion interference. The actual eccentricity is 0.26 mm.

[0067] Fifth, the cycloid disk, eccentric wheel and other components of the cycloid pinwheel reducer are processed separately with the actual eccentricity of 0.26mm as the processing parameter, and the cycloid pinwheel reducer is assembled after the processing is completed.

[0068] After the assembled cycloid pinwheel reducer is driven by the motor, it rotates smoothly, has a correct speed ratio, and the measurement motion accuracy meets the use accuracy requirements.

[0069] The assembled cycloid pinwheel reducer is compared with the harmonic reducer of the same volume as shown in Table 1.

[0070]

[0071] Table 1 is a comparison table of the operating parameters of the two reducers

[0072] As can be seen from Table 1, the transmission efficiency difference between the two is N=46.56%-40.1%=6.46%. After checking, the motor efficiency point is 75%, so the efficiency difference between the two reducers is N1=6.46% / 0.75=8.6%.

[0073] like Figure 3-Figure 4 As shown in the figure, after the assembled cycloid pinwheel reducer is subjected to load torque and sweep frequency tests, the test results meet the sweep frequency indicators of 2 degrees 25HZ and 3 degrees 22HZ (amplitude attenuation is not less than 3dB and phase shift does not exceed 90°).

Claims

1. A micro cycloid pinwheel reducer, characterized in that: It includes a high-speed input mechanism, a reduction mechanism, a low-speed output mechanism and a housing. The high-speed input mechanism and the low-speed output mechanism are respectively nested at both ends of the housing. The reduction mechanism is nested in the housing and is respectively connected to the high-speed input mechanism and the low-speed output mechanism. The high-speed input mechanism includes a large bevel gear and a small bevel gear. The large bevel gear and the small bevel gear are vertically meshed to form a right-angle transmission. One end of the large bevel gear is drivingly connected to the reduction mechanism, and one end of the small bevel gear serves as the power input end of the high-speed input mechanism.

2. The micro-cycloid reducer according to claim 1, characterized in that: The deceleration mechanism includes a pin gear sleeve, a cycloid disk and a pair of eccentric wheels connected in series. The outer periphery of the pair of eccentric wheels is sleeved with a cycloid disk, the cycloid disk is sleeved in the pin gear sleeve, and one end of the pair of eccentric wheels is sleeved with a large bevel gear; the low-speed output mechanism includes a support bearing and an output shaft, a pair of support bearings are respectively nested in one end of the cycloid disk, the output shaft is nested in the support bearing, the outer periphery of the output shaft is sleeved with a pin wheel, one end of the pin wheel is sleeved with a support bearing, and a cycloid needle is arrayed on the pin wheel, and one end of the cycloid needle is inserted into one end of the cycloid disk and connected to the cycloid disk.

3. A method for calculating the eccentricity of the eccentric wheel of the micro-cycloid pinwheel reducer according to claim 1 or 2, characterized in that: The steps include: Step 1: Determine the pitch circle diameter D1 of the cycloid disk of the cycloid pinwheel reducer according to the overall dimensions of the harmonic reducer; Step 2: Obtain the initial range of the eccentricity DS1 of the cycloid pinwheel reducer according to the pitch circle diameter D1 of the pinwheel; wherein DS1 = K1*D1 / Z; (1) (1) In the formula, Z is the number of needle teeth, K1 is the short amplitude coefficient; Step 3, drawing the short-amplitude epicycloid of the cycloid disk according to the short-amplitude coefficient K1; Step 4: Select the eccentricity DS1 corresponding to the short-amplitude epicycloid within the initial range of the eccentricity DS1 as the actual eccentricity of the eccentric wheel.

4. The method for calculating the eccentricity of the eccentric wheel of the micro-cycloid pinwheel reducer according to claim 3 is characterized in that: The short-width coefficient K1 is 0.4 to 0.

8.

5. The method for calculating the eccentricity of the eccentric wheel of the micro-cycloid pinwheel reducer according to claim 4 is characterized in that: The step 3, drawing the short-amplitude epicycloid of the cycloid disk according to the short-amplitude coefficient K1, specifically includes the following steps: Step 301, calculating the curve coordinates of the short-amplitude epicycloid according to the short-amplitude coefficient K1; Among them, the short-amplitude epicycloid is selected as the tooth shape of the cycloid disk, and the curve coordinates of the short-amplitude epicycloid are determined according to the standard tooth shape equation of the cycloid disk (2); (2)In the formula, xc and yc are the curvilinear coordinates of the short-amplitude epicycloid; r p is the radius of the needle roller; r rp is the outer radius of the needle tooth sleeve, in mm; i H is the relative transmission ratio between the cycloid disk and the pinwheel, Among them, zp is the number of teeth of the cycloid disk, and zc is the number of teeth of the pinwheel; is the rotation angle of the arm relative to the center vector of a certain needle tooth, that is, the meshing phase angle; s is a function, indicating a is a constant; Step 302: Draw a short-amplitude epicycloid according to the curve coordinates.

6. The method for calculating the eccentricity of the eccentric wheel of the micro-cycloid pinwheel reducer according to claim 4, characterized in that: In step 4, the eccentricity DS1 corresponding to the short-amplitude epicycloid within the initial range of the eccentricity DS1 is selected as the actual eccentricity of the eccentric wheel, specifically: In the initial range of the eccentricity DS1, the eccentricity DS1 corresponding to the short-amplitude epicycloid without motion interference is selected as the actual eccentricity of the eccentric wheel.

7. The method for calculating the eccentricity of the eccentric wheel of the micro-cycloid pinwheel reducer according to claim 4, characterized in that: The step 1, determining the pitch circle diameter D1 of the cycloid disk of the cycloid pinwheel reducer according to the shape of the harmonic reducer to be replaced, specifically includes the following steps: Step 101, determining the harmonic reducer to be replaced; Step 102: Determine the outer dimensions of the cycloid reducer based on the outer dimensions of the harmonic reducer to be replaced, wherein the outer dimensions of the cycloid reducer are the same as those of the harmonic reducer to be replaced. Step 103: Determine the diameter of the pinwheel of the cycloid pinwheel reducer according to the outer dimensions of the cycloid pinwheel reducer, and determine the pitch circle diameter D1 of the pinwheel of the cycloid disk according to the pinwheel diameter and the reduction ratio of the reducer.

Images