A cycloid gear and a planetary cycloid reducer

Abstract

This invention relates to speed reducers, and more particularly to a cycloidal gear and a planetary cycloidal speed reducer. The cycloidal gear, used in a planetary speed reducer, includes: a gear body with teeth distributed along its outer contour; multiple bearing holes evenly distributed around the rotation axis of the gear body; the contour center of the cycloidal gear is o1, the fitted circle center of the multiple bearing holes is o2, and the distance between o1 and o2 is A; where A is less than a first preset value, the first preset value being the maximum allowable error for the cycloidal gear to rotate normally; thereby achieving the effect of making the planetary cycloidal speed reducer more stable during operation and the two cycloidal gears more evenly stressed.

Description

Technical Field

[0001] This invention relates to speed reducers, and more particularly to a cycloidal gear and a planetary cycloidal speed reducer. Background Technology

[0002] The second-stage cycloidal wheel of the planetary cycloidal reducer is particularly important for the reducer's operation. Due to machining errors, there are eccentric and angular deviations between the fitting circle of the cycloidal wheel bearing hole and the cycloidal wheel profile. When the eccentricity and angular deviations are too large, the force on the cycloidal wheel and pin teeth will be unbalanced. For example, some pin teeth will be under great force, while others will be under little force, or even the force direction of some pin teeth will be opposite to the transmission direction, hindering the transmission of the cycloidal wheel. The eccentricity angle and angular direction of the two cycloidal wheels of the planetary reducer are different, which leads to an imbalance of force on the two cycloidal wheels during operation. One cycloidal wheel will be under greater force, while the other will be relatively under less force. Over time, this will accelerate the wear of the cycloidal wheel and pin teeth, making the transmission unstable, generating noise and vibration. Not only will the transmission accuracy be affected, but the service life will also be reduced.

[0003] Patent CN111765211A provides an internal meshing RV-C type reducer for industrial robots. After modifying the cycloidal wheel, a reasonable clearance (radial clearance Δj and side clearance Δc) is created between the internal cycloidal teeth and the cycloidal tooth groove. This prevents the meshing parts from jamming when the cycloidal wheel thermally expands under rated load. Furthermore, it simplifies the structure of the internal cycloidal gear ring and improves load-bearing capacity through concave-convex meshing. However, this solution only considers the clearance between the cycloidal and pin teeth under thermal expansion, neglecting the influence of the cycloidal wheel's own deviations. If there is eccentricity at the center of the cycloidal wheel's entire contour or angular deviation in the contour, interference between the pin and cycloidal meshing and jamming may occur.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] To make the planetary cycloidal reducer operate more smoothly and the force on the two cycloidal gears more balanced, this invention provides a cycloidal gear and a planetary cycloidal reducer.

[0006] On one hand, a cycloidal gear is used in a planetary reducer. The cycloidal gear includes: a gear body, teeth distributed on the outer contour of the gear body, and multiple bearing holes on the gear body, the multiple bearing holes being evenly distributed around the rotation axis of the gear body.

[0007] The contour center of the cycloidal gear is o1, the fitting circle center of the plurality of bearing holes is o2, and the distance between o1 and o2 is A; then A is less than a first preset value, which is the maximum error allowed for the cycloidal gear to rotate normally.

[0008] Preferably, the diameter of the pin teeth disposed around the cycloidal gear is d, and the diameter of the distribution circle of the pin teeth is D;

[0009] Then A = D - R1 - R2 - d; 0 ≤ A ≤ 0.002 mm; the first preset value is greater than 0.002 mm; R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear.

[0010] Preferably, the plurality of bearing holes include a positioning bearing hole, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; a ray passing through o4 and o3 and extending from o4 to o3 is L1, the tooth passing through which L1 passes is a positioning tooth, the straight line passing through o4 and the center of the tooth surface of the positioning tooth is L2, and the acute angle formed by the projections of L1 and L2 in the axial direction is the deflection angle α.

[0011] but 0≤m≤0.005mm; m is the profile deviation of the cycloidal gear corresponding to α, R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear.

[0012] Preferably, the plurality of bearing holes include a positioning bearing hole, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; a ray passing through o4 and o3 and extending from o4 to o3 is L3, the tooth groove through which L3 passes is a positioning tooth groove, the straight line passing through o4 and the center of the tooth surface of the positioning gear is L4, and the acute angle formed by the projections of L3 and L4 in the axial direction is the deflection angle β.

[0013] but 0≤m≤0.005mm; n is the profile deviation of the cycloidal gear corresponding to β, R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear.

[0014] Preferably, the cycloidal gear includes: a gear body, teeth distributed on the outer contour of the gear body, and multiple bearing holes on the gear body, the multiple bearing holes being evenly distributed around the rotation axis of the gear body;

[0015] The plurality of bearing holes include a positioning bearing hole, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; a ray passing through o4 and o3 and extending from o4 to o3 is L5, L5 passes through the positioning structure on the edge of the gear body, and a straight line passing through the center of o4 and the positioning structure is L6; the acute angle formed by the projections of L5 and L6 in the axial direction is the deflection angle θ.

[0016] but If p is less than the second preset value, the second preset value is the maximum error allowed for the cycloidal gear to rotate normally, p is the profile deviation of the cycloidal gear corresponding to θ, R1 is the addendum circle radius of the cycloidal gear, and R2 is the root circle radius of the cycloidal gear.

[0017] Preferably, the positioning structure is a gear tooth, and the center of the positioning structure is the center of the projection of the tooth surface in the axial direction.

[0018] Preferably, the positioning structure is a tooth groove, and the center of the positioning structure is the center of the projection of the tooth surface of the tooth groove in the axial direction.

[0019] Preferably, 0 ≤ p ≤ 0.005 mm.

[0020] Preferably, the diameter of the pin teeth disposed around the cycloidal gear is d, and the diameter of the distribution circle of the pin teeth is D;

[0021] Then A = D - R1 - R2 - d; 0 ≤ A ≤ 0.002 mm; the first preset value is greater than 0.002 mm; R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear.

[0022] On the other hand, the present invention also provides a planetary reducer, including the aforementioned cycloidal gear; there are two cycloidal gears, namely a first gear and a second gear; the first gear and the second gear are configured such that when the first gear is translated so that the contour center of the first gear is coaxial with the contour center of the second gear, the distance A1 between the fitting circle center of the bearing hole of the first gear and the fitting circle center of the bearing hole of the second gear is 0≤A1≤0.002mm.

[0023] Preferably, the deflection angle of the first gear is γ1, and its corresponding profile deviation is f1; the deflection angle of the second gear is γ2, and its corresponding profile deviation is f2.

[0024] The first gear and the second gear are configured such that when the deflection angle γ1 of the first gear and the deflection angle γ2 of the second gear are opposite in the direction of deflection in the circumferential direction, (f1+f2)≤0.005mm.

[0025] This invention effectively prevents the force between some teeth and pins from being opposite to the transmission direction during rotation of the cycloidal gear by controlling the distance between the contour center of the cycloidal gear and the fitting circle center of the bearing hole. It also prevents uneven force between the cycloidal gear teeth and pins by controlling the contour deviation of the cycloidal gear, thus avoiding excessive force, abnormal vibration, accelerated wear, and reduced precision. Planetary reducers using this cycloidal gear operate smoothly, have higher precision, and longer service life. Attached Figure Description

[0026] Figure 1 This is a schematic diagram showing the relationship between the contour center and the fitting circle center of the cycloidal gear in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the cycloidal gear in an embodiment of the present invention when the deflection angle is α;

[0028] Figure 3 This is a schematic diagram of the cycloidal gear in an embodiment of the present invention when the deflection angle is β;

[0029] Figure 4 This is a schematic diagram of the cycloidal gear with a deflection angle of θ according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram showing the relationship between the centers of two fitted circles when the contour centers of the first gear and the second gear in an embodiment of the present invention coincide.

[0031] Figure 6 This is a schematic diagram showing the two fitted circles offset in the same direction when the contour centers of the first gear and the second gear in an embodiment of the present invention coincide.

[0032] Figure 7 This is a schematic diagram showing the two fitted circles deviating in opposite directions when the contour centers of the first gear and the second gear coincide in an embodiment of the present invention.

[0033] Figure 8 This is a schematic diagram of the first gear and the second gear in an embodiment of the present invention when their deflection angles are in opposite directions.

[0034] Figure 9 This is a schematic diagram of the first gear and the second gear in an embodiment of the present invention when their deflection angles are in the same direction;

[0035] Figure 10 This is a schematic diagram of a planetary reducer according to an embodiment of the present invention;

[0036] Figure 11 This is a coordinate graph showing the relationship between the maximum force and the eccentricity at the meshing point of a single cycloidal gear in the planetary reducer of this embodiment of the invention.

[0037] Figure 12 This is a coordinate graph showing the relationship between the ratio of the maximum force at the meshing point of the two cycloidal gears and the cumulative eccentricity of the two cycloidal gears in the planetary reducer of this embodiment of the invention.

[0038] Figure 13 This is a coordinate graph showing the relationship between the maximum force and the profile deviation at the meshing point of a single cycloidal gear in the planetary reducer of this embodiment of the invention.

[0039] Figure 14 This is a coordinate graph showing the relationship between the ratio of the maximum force at the meshing point of the two cycloidal gears in the planetary reducer of this embodiment of the invention and the magnitude of the cumulative eccentricity.

[0040] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0041] In the attached drawings: 1-Gear body; 2-Gear teeth; 3-Bearing hole; 301-Positioning bearing hole; 4-First gear; 5-Second gear; 6-Positioning gear teeth; 7-Positioning tooth groove; 8-Pin tooth pin. Detailed Implementation

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0044] This invention relates to speed reducers, and more particularly to a cycloidal gear and a planetary cycloidal speed reducer. The second-stage cycloidal wheel of the planetary cycloidal speed reducer is particularly important for the operation of the speed reducer. Due to machining errors, the fitting circle of the cycloidal wheel bearing hole and the cycloidal wheel profile will have eccentricity and angular deviation. When the eccentricity and angular deviation are too large, the force on the cycloidal wheel and the pin teeth will be unbalanced. For example, some pin teeth will have a large force, some pin teeth will have a small force, and some pin teeth may even have a force direction opposite to the transmission direction, which will hinder the transmission of the cycloidal wheel. The eccentricity angle and angular direction of the two cycloidal wheels are different, which makes the transmission unstable, generates noise and vibration, and not only affects the transmission accuracy, but also reduces the service life.

[0045] To address the above problems, the present invention provides a cycloidal gear and a planetary cycloidal reducer;

[0046] like Figure 1-14 As shown, a cycloidal gear is used in a planetary reducer. The cycloidal gear includes: a gear body 1, with teeth 2 distributed on the outer contour of the gear body 1, and multiple bearing holes 3 evenly distributed around the rotation axis of the gear body 1; the contour center of the cycloidal gear is o1, the fitting circle center of the multiple bearing holes 3 is o2, and the distance between o1 and o2 is A; then A is less than a first preset value, which is the maximum allowable error for the cycloidal gear to rotate normally; A is also called the eccentricity value; by controlling the distance between the contour center of the cycloidal gear and the fitting circle center on the bearing hole 3 within the first preset value range, when the cycloidal gear is working, when some teeth of the cycloidal gear are fully engaged with the pin 8 to transmit force, the other part of the gear, which is symmetrical about the center of the cycloidal gear, is completely separated from the pin 8 or experiences minimal interference. The interference part has minimal impact on the cycloidal gear due to the deformation of the pin 8 and the cycloidal gear itself, as well as the effect of lubrication, thereby achieving the purpose of the cycloidal gear always being subjected to force in one direction.

[0047] Preferred, such as Figure 1 As shown, the diameter of the pin 8 set around the cycloidal gear is d, and the diameter of the distribution circle of the pin 8 is D; then A = D - R1 - R2 - d; 0 ≤ A ≤ 0.002 mm; the first preset value is greater than 0.002 mm; R1 is the addendum circle radius of the cycloidal gear, and R2 is the root circle radius of the cycloidal gear; by controlling the value of A within 0.002, the interference force between the cycloidal gear and the pin 8 is greatly reduced. When A = 0.002 mm, the radial force between the gear tooth 2 and the pin 8 in the cycloidal gear reaches 1350 N. When A is greater than 0.002 mm, the force when the gear tooth 2 meshes with the pin 8 is greater, and the wear is also greater; as Figure 11 As shown, in the experiment, the magnitude of the eccentricity value A of the cycloidal gear was controlled, and the maximum force at the meshing point of the cycloidal gear was detected. The experimental results were plotted as follows: Figure 11 The chart, Figure 11 The horizontal axis represents the eccentricity of a single cycloidal gear, and the vertical axis represents the maximum force at the meshing point of a single cycloidal gear. The maximum force at the meshing point of the cycloidal gear increases with the increase of the eccentricity. Controlling A to no more than 0.002 mm effectively reduces the force between the pin 8 and the cycloidal gear in the radial direction of the cycloidal gear, reduces excessive wear, and helps to improve service life.

[0048] Preferred, such as Figure 2 As shown, the plurality of bearing holes 3 include a positioning bearing hole 301, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; the ray passing through o4 and o3 and extending from o4 to o3 is L1, the gear tooth 2 that L1 passes through is the positioning gear tooth 62, the straight line passing through the center of the tooth surface of o4 and the positioning gear tooth 62 is L2, and the acute angle formed by the projections of L1 and L2 in the axial direction is the deflection angle α. 0≤m≤0.005mm; m is the profile deviation of the cycloidal gear corresponding to α, R1 is the addendum circle radius of the cycloidal gear, and R2 is the root circle radius of the cycloidal gear; by controlling the profile deviation of the cycloidal gear, the force between the gear tooth 2 and the pin 8 decreases more evenly from the fully meshing end to the fully disengaged end, and conversely, increases more evenly; this avoids excessive force on some gear teeth 2 and pin 8, which would lead to rapid wear and abnormal vibration and noise.

[0049] Preferred, such as Figure 3 As shown, the plurality of bearing holes 3 include a positioning bearing hole 301, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; the ray passing through o4 and o3 and extending from o4 to o3 is L3, the tooth groove through which L3 passes is the positioning tooth groove 7, the straight line passing through the center of the tooth surface of o4 and the positioning gear tooth 62 is L4, and the acute angle formed by the projections of L3 and L4 in the axial direction is the deflection angle β. 0 ≤ n ≤ 0.005 mm; n is the profile deviation of the cycloidal gear corresponding to β, R1 is the addendum circle radius of the cycloidal gear, and R2 is the root circle radius of the cycloidal gear; by controlling the profile deviation of the cycloidal gear, the force between the gear tooth 2 and the pin 8 decreases more evenly from the fully meshing end to the fully disengaged end, and conversely, increases more evenly; that is, under the premise of a certain output power, as β increases, the contact force between the cycloidal gear and the pin 8 also increases, the useless work in the contact force increases, and the rate of increase of the contact force is greater than the rate of increase of β; when n = 0.005 mm, the maximum contact force reaches 1300 N, and wear begins to increase rapidly; such as Figure 13As shown, the magnitude of the profile deviation of a single cycloidal gear is controlled, the maximum force at the meshing point of the cycloidal gear corresponding to the profile deviation is detected, and the detection results are plotted as shown. Figure 13 The chart, Figure 13 The horizontal axis represents the profile deviation value of a single cycloidal gear, and the vertical axis represents the maximum force value at the meshing point of a single cycloidal gear; from Figure 13 It can be concluded that the maximum force at the meshing point of the cycloidal gear increases with the increase of the profile deviation. Since the profile deviation is directly proportional to the deflection angle of the cycloidal gear, that is, as the deflection angle gradually increases, the profile deviation also gradually increases. Figure 13 The same conclusion can be reached by replacing the x-axis with the deflection angle of the cycloidal gear; when 0≤n≤0.005mm, it can avoid excessive force on some gear teeth 2 and pin 8, which would lead to rapid wear and abnormal vibration and noise; taking the center of the tooth surface of gear teeth 2 as the reference and the center of the tooth groove as the reference are design and processing requirements.

[0050] A cycloidal gear includes: Figure 4 As shown, the gear body 1 has teeth 2 distributed along its outer contour. Multiple bearing holes 3 are evenly distributed around the rotation axis of the gear body 1. Among the bearing holes 3 is a positioning bearing hole 301, with its center at o3. The cycloidal gear includes a designed rotation center at o4. A ray L5 extends from o4 to o3, passing through the positioning structure at the edge of the gear body 1. A straight line L6 passes through the center of o4 and the positioning structure. The acute angle formed by the projections of L5 and L6 in the axial direction is the deflection angle θ. If p is less than the second preset value, which is the maximum allowable error for the cycloidal gear to rotate normally, p is the profile deviation of the cycloidal gear corresponding to θ, R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear. By controlling the profile deviation of the cycloidal gear, the force between the gear tooth 2 and the pin 8 decreases more evenly from the fully meshed end to the fully separated end, and conversely, increases more evenly. This avoids excessive force on some gear teeth 2 and pin 8, which would lead to rapid wear and abnormal vibration and noise. Using the center of the tooth surface of gear tooth 2 as a reference and the center of the tooth groove as a reference are design and manufacturing requirements.

[0051] Preferably, the positioning structure is a tooth 2, and the center of the positioning structure is the center of the projection of the tooth surface of the tooth 2 in the axial direction; or, the positioning structure is a tooth groove, and the center of the positioning structure is the center of the projection of the tooth surface of the tooth groove in the axial direction; 0≤p≤0.005mm;

[0052] Preferably, the diameter of the pin 8 set around the cycloidal gear is d, and the diameter of the distribution circle of the pin 8 is D; then A = D - R1 - R2 - d; 0 ≤ A ≤ 0.002 mm; the first preset value is greater than 0.002 mm; R1 is the addendum circle radius of the cycloidal gear, and R2 is the root circle radius of the cycloidal gear.

[0053] On the other hand, the present invention also provides a planetary reducer, such as Figure 10 As shown, it includes a cycloidal gear; there are two cycloidal gears, namely a first gear 4 and a second gear 5; the first gear 4 and the second gear 5 are configured such that when the first gear 4 is translated so that the contour center of the first gear 4 is coaxial with the contour center of the second gear 5, as... Figure 5 As shown, the distance A1 between the center of the fitting circle of the bearing hole 3 of the first gear 4 and the center of the fitting circle of the bearing hole 3 of the second gear 5 is 0≤A1≤0.002mm. The eccentricity value of the first gear 4 is A2, and the eccentricity value of the second gear 5 is A3, making the contour centers of the two gears coaxial. At this time, the distance A1 between the centers of the fitting circles of the two gears is... During operation, there is an accumulation of eccentricity values ​​between the two cycloidal gears. The eccentricity value of each cycloidal gear is no greater than 0.002mm. Since the eccentricity directions of the fitting circle centers of the two cycloidal gears relative to the contour centers may be opposite, when the eccentricity directions are completely opposite, such as... Figure 7 As shown, even if the eccentricity of each cycloidal gear is no greater than 0.002 mm, when two cycloidal gears work together, the cumulative deviation A1 can reach 0.004 mm, causing a significant increase in the force between the two cycloidal gears and the pin 8, and a significant increase in wear; when the eccentricity directions of the two cycloidal gears are consistent, such as Figure 6 As shown, this results in extremely uneven force distribution on the two cycloidal gears. One cycloidal gear experiences a large force with the pin 8, while the other experiences a small force. The wear between the cycloidal gear and the pin 8 also differs. Over time, this leads to uneven loads on the two cycloidal gears, and the difference becomes increasingly pronounced. The superposition of eccentricity values ​​is directly proportional to the load distribution on the cycloidal gears, as shown in the diagram. Figure 12 As shown, the cumulative eccentricity of the two cycloidal gears in the planetary reducer is controlled, the maximum force value of the two cycloidal gears at their respective meshing points with the pinion is detected, and the two maximum force values ​​are compared to obtain the ratio of the maximum force of the two cycloidal gears. Figure 12 The horizontal axis represents the cumulative eccentricity of the two cycloidal gears, and the vertical axis represents the maximum force distribution ratio at the meshing point of the two cycloidal gears; from Figure 12It can be concluded that the maximum force ratio of the two cycloidal gears increases with the increase of the cumulative eccentricity. That is, the increase of the cumulative eccentricity of the two cycloidal gears leads to an increase in the ratio of the maximum force of each cycloidal gear, and the corresponding difference in force between the two cycloidal gears also increases. When A1 = 0.002mm, the ratio reaches 1:1.5. Controlling the cumulative deviation within 0.002mm can control the processing cost and effectively avoid the situation where the maximum force ratio at the meshing point of the two cycloidal gears is too large. This effectively ensures the smooth operation of the planetary reducer, avoids unnecessary noise and vibration, and also improves its service life.

[0054] Preferably, the deflection angle of the first gear 4 is γ1, and its corresponding profile deviation is f1; the deflection angle of the second gear 5 is γ2, and its corresponding profile deviation is f2; the first gear 4 and the second gear 5 are configured as follows: Figure 8 As shown, when the deflection angle γ1 of the first gear 4 and the deflection angle γ2 of the second gear 5 are opposite in direction in the circumferential direction, γ = γ1 + γ2, and the cumulative deflection angle γ is greater than γ1 and γ2; as Figure 9 As shown, when the deflection angle γ1 of the first gear 4 and the deflection angle γ2 of the second gear 5 are in the same direction in the circumferential direction, γ = γ1 - γ2. Here, the magnitudes of γ1 and γ2 can be interchanged, meaning the cumulative profile deviation γ is less than γ1 and γ2. It is sufficient to ensure that (f1 + f2) ≤ 0.005 mm. When the deflection angles are in the same direction, because the profile deviation corresponding to a single deflection angle is no greater than 0.005 mm, the difference between the two profile deviations is also no greater than 0.005 mm. The larger the cumulative profile deviation, the greater the load differentiation ratio between the two cycloidal gears, resulting in a larger load on one cycloidal gear and a smaller load on the other. When the cumulative profile deviation reaches 0.005 mm, the load differentiation between the two cycloidal gears reaches 1:1.4. One cycloidal gear experiences prolonged overload, leading to accelerated wear. Consequently, the difference in the outer profile size between the two cycloidal gears increases, exacerbating the load differentiation and causing the entire machine to malfunction, reducing the service life of the planetary reducer. Figure 14 As shown, the cumulative profile deviation of the two cycloidal gears in the planetary reducer is controlled. The maximum force at the meshing point of each cycloidal gear with the pinion is detected. The obtained maximum values ​​of the two cycloidal gears are compared to obtain the maximum force ratio at the core of the two cycloidal gears. The horizontal axis of the figure represents the cumulative profile deviation of the two cycloidal gears, and the vertical axis represents the maximum force ratio at the meshing point of the two cycloidal gears. Figure 14As can be seen, the maximum force ratio at the meshing point of the two cycloidal gears increases with the increase of the cumulative deviation of the two cycloidal gear profiles. The cumulative deviation (f1+f2)≤0.005mm is effectively avoided, thus preventing the phenomenon of severe load differentiation caused by the accumulation of the profile deviation of the two cycloidal gears. This effectively ensures the smooth operation of the planetary reducer, avoids abnormal noise and vibration, and also improves its service life.

[0055] The present invention has the following significant advantages:

[0056] 1. This invention effectively avoids interference between the radially opposite portion of the meshing teeth of the cycloidal gear and the pin tooth pin during planetary reducer operation by controlling the eccentricity value A of a single cycloidal gear in the planetary reducer, as well as the cumulative eccentricity value of the two cycloidal gears. This prevents the meshing teeth and the radially opposite portion of the teeth from experiencing opposite forces. Alternatively, it minimizes interference between the radially opposite portion of the meshing teeth of the cycloidal gear and the pin tooth pin during planetary reducer operation, ensuring normal operation of the cycloidal gear and reducing abnormal noise, vibration, and wear. This ensures smooth operation of the planetary reducer and extends its service life. Controlling the cumulative eccentricity value prevents an excessively large ratio of the maximum force between the two cycloidal gears and the pin tooth pin, ensuring balanced force on the two cycloidal gears, further reducing noise and vibration during planetary reducer operation, ensuring smooth operation, and extending service life.

[0057] 2. This invention effectively avoids uneven force between different teeth and corresponding pins when the cycloidal gear meshes with the pin pin during planetary reducer operation by controlling the magnitude of the profile deviation value (bias angle) of a single cycloidal gear in the planetary reducer, as well as the magnitude of the cumulative profile deviation value (cumulative bias angle value) of two cycloidal gears. This further avoids excessive force between some teeth and pins, preventing abnormal vibration and noise, and also avoids abnormal wear caused by this. This ensures smooth operation of the planetary reducer and improves its service life. Controlling the cumulative profile deviation value prevents the ratio of the maximum force between the two cycloidal gears and the pins from being too large, ensuring balanced force on the two cycloidal gears, further reducing noise and vibration during planetary reducer operation, ensuring smooth operation of the planetary reducer, and improving its service life.

[0058] Exemplary embodiments of this disclosure have been specifically shown and described above. It should be understood that this disclosure is not limited to the detailed structures, arrangements, or implementations described herein; rather, this disclosure is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A cycloidal gear for use in a planetary reducer, characterized in that, The cycloidal gear includes: a gear body, teeth distributed on the outer contour of the gear body, and multiple bearing holes on the gear body, the multiple bearing holes being evenly distributed around the rotation axis of the gear body; The contour center of the cycloidal gear is o1, the fitting circle center of the plurality of bearing holes is o2, and the distance between o1 and o2 is A; then A is less than a first preset value, which is the maximum error allowed for the cycloidal gear to rotate normally.

2. A cycloidal gear according to claim 1, characterized in that, The diameter of the pin teeth arranged around the cycloidal gear is d, and the diameter of the distribution circle of the pin teeth is D. Then A = D - R1 - R2 - d; 0 ≤ A ≤ 0.002 mm; the first preset value is greater than 0.002 mm; R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear.

3. A cycloidal gear according to claim 2, characterized in that, The plurality of bearing holes include a positioning bearing hole, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; a ray passing through o4 and o3 and extending from o4 to o3 is L1, the tooth through which L1 passes is a positioning tooth, the straight line passing through o4 and the center of the tooth surface of the positioning tooth is L2, and the acute angle formed by the projections of L1 and L2 in the axial direction is the deflection angle α. but 0≤m≤0.005mm; m is the profile deviation of the cycloidal gear corresponding to α, R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear.

4. A cycloidal gear according to claim 2, characterized in that, The plurality of bearing holes include a positioning bearing hole, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; a ray passing through o4 and o3 and extending from o4 to o3 is L3, the tooth groove through which L3 passes is a positioning tooth groove, the straight line passing through the center of the tooth surface of o4 and the positioning tooth groove is L4, and the acute angle formed by the projections of L3 and L4 in the axial direction is the deflection angle β. but 0≤n≤0.005mm; n is the profile deviation of the cycloidal gear corresponding to β, R1 is the addendum circle radius of the cycloidal gear, and R2 is the root circle radius of the cycloidal gear.

5. A cycloidal gear for use in a planetary reducer, characterized in that, The cycloidal gear includes: a gear body, teeth distributed on the outer contour of the gear body, and multiple bearing holes on the gear body, the multiple bearing holes being evenly distributed around the rotation axis of the gear body; The plurality of bearing holes include a positioning bearing hole, the center of which is o3; the cycloidal gear includes a designed rotation center, which is o4; a ray passing through o4 and o3 and extending from o4 to o3 is L5, L5 passes through the positioning structure on the edge of the gear body, and a straight line passing through the center of o4 and the positioning structure is L6; the acute angle formed by the projections of L5 and L6 in the axial direction is the deflection angle θ. but If p is less than the second preset value, the second preset value is the maximum error allowed for the cycloidal gear to rotate normally, p is the profile deviation of the cycloidal gear corresponding to θ, R1 is the addendum circle radius of the cycloidal gear, and R2 is the root circle radius of the cycloidal gear.

6. A cycloidal gear according to claim 5, characterized in that, The positioning structure is a gear tooth, and the center of the positioning structure is the center of the projection of the tooth surface in the axial direction.

7. A cycloidal gear according to claim 5, characterized in that, The positioning structure is a tooth groove, and the center of the positioning structure is the center of the projection of the tooth surface of the tooth groove in the axial direction.

8. A cycloidal gear according to claim 6 or 7, characterized in that, 0≤p≤0.005mm.

9. A cycloidal gear according to claim 8, characterized in that, The diameter of the pin teeth arranged around the cycloidal gear is d, and the diameter of the distribution circle of the pin teeth is D. Then A = D - R1 - R2 - d; 0 ≤ A ≤ 0.002 mm; the first preset value is greater than 0.002 mm; R1 is the addendum circle radius of the cycloidal gear, and R2 is the dedendum circle radius of the cycloidal gear.

10. A planetary reducer, characterized in that, The invention includes a cycloidal gear as described in claim 4 or 9; there are two cycloidal gears, namely a first gear and a second gear; the first gear and the second gear are configured such that when the first gear is translated so that the contour center of the first gear is coaxial with the contour center of the second gear, the distance A1 between the fitting circle center of the bearing hole of the first gear and the fitting circle center of the bearing hole of the second gear is 0 ≤ A1 ≤ 0.002 mm.

11. A planetary reducer according to claim 10, characterized in that, The first gear has a deflection angle of γ1 and a corresponding profile deviation of f1; the second gear has a deflection angle of γ2 and a corresponding profile deviation of f2. The first gear and the second gear are configured such that when the deflection angle γ1 of the first gear and the deflection angle γ2 of the second gear are opposite in the direction of deflection in the circumferential direction, (f1+f2)≤0.005mm.

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