Rigid wheel, harmonic speed reducer and industrial robot

Abstract

The utility model discloses a rigid gear, harmonic reducer and industrial robot belongs to transmission device technical field, the rigid gear includes the body, the body has the inner bore, along the axial direction of inner bore, the inner peripheral wall of inner bore is equipped with first wall surface and second wall surface in proper order, the first wall surface forms the internal tooth part, the internal tooth part is arranged along the circumferential direction of first wall surface, and the second wall surface is equipped with the second wall surface. As the inner diameter of the second wall surface is larger than that of the first wall surface, a step surface can be constructed between the second wall surface and the first wall surface, and a concave space is defined on the inner wall of the inner hole through the step surface and the second wall surface, so that the inner side of the rigid gear has more space for being filled with lubricating grease, and the rigid gear is suitable for the harmonic speed reducer; the lubricating performance between the rigid gear and the flexible gear is effectively improved, the risk of abrasion between the rigid gear and the flexible gear is reduced, and therefore the reliability of the harmonic speed reducer is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of transmission devices, in particular to a rigid wheel, a harmonic reducer and an industrial robot. Background Art

[0002] The harmonic reducer transmits motion through the meshing between teeth. When the wave generator is running, the flexible wheel will be forced to produce periodic elastic deformation. During this deformation process, the outer teeth of the flexible wheel will mesh with the inner teeth of the rigid wheel. Since the meshing area between the inner teeth of the rigid wheel and the outer teeth of the flexible wheel is large, the end face of the flexible wheel presents a periodic bell-mouth deformation during the operation of the wave generator, causing the flexible wheel to have periodic circumferential motion and axial movement, which makes it easy for friction to occur between the rigid wheel and the flexible wheel, increasing the risk of wear between the rigid wheel and the flexible wheel, and reducing the reliability of the harmonic reducer. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a rigid wheel that can be filled with more lubricating oil, effectively improving the lubrication performance between the rigid wheel and the flexible wheel, and reducing the risk of wear.

[0004] The utility model also provides a harmonic reducer and an industrial robot including the rigid wheel.

[0005] According to the first aspect of the present invention, the rigid wheel includes a main body, the main body has an inner hole, and along the axial direction of the inner hole, the inner circumferential wall of the inner hole is provided with a first wall surface and a second wall surface in sequence, the first wall surface is formed with an inner tooth portion, and the inner tooth portion is arranged along the circumference of the first wall surface, the inner diameter of the second wall surface is larger than the inner diameter of the first wall surface, and the second wall surface is constructed as a step surface with the first wall surface, and the step surface and the second wall surface define a recessed space for filling lubricating oil.

[0006] The rigid wheel according to the embodiment of the utility model has at least the following beneficial effects:

[0007] The inner circumferential wall of the inner hole of the rigid wheel is provided with a first wall surface and a second wall surface, and the first wall surface and the second wall surface are arranged in sequence along the axial direction of the inner hole, and the inner tooth portion of the rigid wheel is arranged on the first wall surface. Since the inner diameter of the second wall surface is larger than the inner diameter of the first wall surface, the second wall surface and the first wall surface can be constructed as a step surface, and a recessed space is defined on the inner wall of the inner hole by the step surface and the second wall surface, so that the inner side of the rigid wheel has more space for filling lubricating oil. It is suitable for harmonic reducers, effectively improves the lubrication performance between the rigid wheel and the flexible wheel, reduces the risk of wear between the rigid wheel and the flexible wheel, and thus improves the reliability of the harmonic reducer.

[0008] According to some embodiments of the present invention, along the axial direction of the inner hole, the width of the second wall surface is greater than or equal to the width of the first wall surface.

[0009] According to some embodiments of the present invention, along the axial direction of the inner hole, the width of the body is a, and the width of the second wall surface is b, satisfying: a*50%≤b≤a*60%.

[0010] According to some embodiments of the present invention, along the radial direction of the inner hole, the distance between the first wall surface and the second wall surface is h, and the outer diameter of the body is D, satisfying: D*5%≤h≤D*10%.

[0011] According to some embodiments of the present invention, the angle between the second wall surface and the step surface ranges from 90° to 150°.

[0012] According to the harmonic reducer of the second aspect embodiment of the utility model, it includes a flexible wheel, a wave generator and the rigid wheel described in the first aspect embodiment; the flexible wheel is provided with an outer tooth portion, and the flexible wheel is installed in the inner hole; the wave generator is installed on the inner side of the flexible wheel, and the wave generator is configured to make the outer tooth portion mesh with the inner tooth portion when rotating.

[0013] The harmonic reducer according to the embodiment of the utility model has at least the following beneficial effects:

[0014] The harmonic reducer applies the flexible wheel of the above embodiment, and the flexible wheel is installed in the inner hole of the rigid wheel. The wave generator can make the outer tooth portion mesh with the inner tooth portion during operation. Since the inner side of the rigid wheel has more space for filling lubricating oil, the lubrication performance between the rigid wheel and the flexible wheel is effectively improved, and the risk of wear between the rigid wheel and the flexible wheel is reduced, thereby improving the reliability of the harmonic reducer.

[0015] According to some embodiments of the present invention, along the axial direction of the rigid wheel, the maximum width of the inner tooth portion is c, and the maximum width of the outer tooth portion is d, satisfying: d*80%≤c≤d*100%.

[0016] According to some embodiments of the utility model, the flexible wheel includes a cylindrical portion, the external tooth portion is formed on a portion of the outer peripheral wall of the cylindrical portion, and the cylindrical portion is arranged along the axial direction of the rigid wheel toward the second wall surface, so that an annular groove is defined between the outer wall of the cylindrical portion, the second wall surface and the step surface.

[0017] According to some embodiments of the utility model, the harmonic reducer also includes an output assembly, a connecting portion is provided at one end of the cylinder away from the external tooth portion, the output assembly is connected to the connecting portion, and the second wall surface is formed at one end of the rigid wheel facing the output assembly.

[0018] The industrial robot according to the embodiment of the third aspect of the utility model includes the harmonic reducer described in the second aspect.

[0019] Since the industrial robot includes the harmonic reducer of the above embodiment, it has at least the above beneficial effects, which will not be described in detail here.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 It is a schematic diagram of the cross-sectional structure of a rigid wheel in a harmonic reducer in some embodiments of the utility model;

[0023] Figure 2 for Figure 1 A schematic diagram of the enlarged structure at A in the middle;

[0024] Figure 3 It is a schematic diagram of the cross-sectional structure of the harmonic reducer of some embodiments of the utility model;

[0025] Figure 4 It is a schematic cross-sectional structure diagram of a flexible wheel in a harmonic reducer in some embodiments of the utility model;

[0026] Figure 5 for Figure 3 Schematic diagram of the enlarged structure at point B in the middle.

[0027] Reference numerals:

[0028] Harmonic reducer 10;

[0029] The wheel 100; the body 110; the first wall surface 111; the second wall surface 112; the inner tooth portion 113; the step surface 114; the inner hole 120; the recessed space 121; the boss 130; the first connecting hole 131;

[0030] Flexspline 200; cylinder 210; external tooth 211; connecting portion 220; flange 230;

[0031] Wave generator 300; flexible bearing 310; cam 320;

[0032] Output assembly 400; fixed portion 410; second connection hole 411; rotating portion 420;

[0033] Annular groove 500;

[0034] Connecting bolt 600. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the description of the present invention, it should be understood that the descriptions involving orientations, such as up, down, left, right, circumferential, axial, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] In the description of the utility model, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0038] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0039] The harmonic reducer transmits motion through the meshing between teeth. During the entire motion process, the meshing area between the inner teeth of the rigid wheel and the outer teeth of the flexible wheel is large, and the meshing tooth pairs account for about 30%. Since the flexible wheel is a thin-walled structure, it presents the same shape as the cam after the wave generator is assembled. During the operation of the wave generator, the end face of the flexible wheel presents a periodic bell-mouth deformation form. The end face of the flexible wheel is a curved surface. There is periodic circumferential motion and axial movement between the outer ring of the flexible bearing and the inside of the flexible wheel. Friction will occur between the outer ring of the flexible bearing and the inner wall of the flexible wheel, and between the outer wall of the flexible wheel and the inner wall of the rigid wheel.

[0040] The outer ring of the flexible bearing and the inner wall of the flexible wheel are the friction pairs that contribute the most to the wear during the entire life cycle of the reducer. Since the main load-bearing area of ​​the flexible bearing is the long axis area, and the inner raceway and roller of the flexible bearing are in non-conformal contact, its long axis area is in a state of large contact stress during operation. Poor lubrication of the inner raceway of the flexible bearing will cause wear of the inner raceway. Therefore, most of the related technologies use the honing process of the inner wall of the flexible wheel and the nitriding process of the flexible wheel to improve the wear here, but they do not consider the improvement of the wear of the rigid wheel. The wear problem between the flexible wheel and the rigid wheel also seriously restricts the reliability of the harmonic reducer.

[0041] In order to improve the reliability of the harmonic reducer, the utility model proposes a rigid wheel, which optimizes the structure of the rigid wheel, effectively improves the lubrication performance between the rigid wheel and the flexible wheel, improves the wear problem between the rigid wheel and the flexible wheel, and thus improves the reliability of the harmonic reducer. The following is a description of the rigid wheel and the harmonic reducer with specific examples in conjunction with the accompanying drawings.

[0042] Reference Figure 1 As shown, a rigid wheel 100 proposed in an embodiment of the utility model is applied to a harmonic reducer 10. Figure 1 , the cross-sectional structure of the rigid wheel 100 along its axial direction is shown. The rigid wheel 100 is an annular internal gear ring rigid gear. The rigid wheel 100 specifically includes a body 110. The body 110 is annular and has an inner hole 120. The inner hole 120 penetrates the body 110 along the axial direction of the rigid wheel 100. The inner wall of the inner hole 120 is provided with an inner tooth portion 113. The inner hole 120 is used to install the flexible wheel 200. The wave generator 300 is installed on the inner side of the flexible wheel 200. The inner tooth portion 113 can mesh with the outer tooth portion 211 of the flexible wheel 200.

[0043] In the embodiment of the utility model, the inner peripheral wall of the inner hole 120 of the rigid wheel 100 is provided with a first wall surface 111 and a second wall surface 112, and the first wall surface 111 and the second wall surface 112 are both annular and arranged in sequence along the axial direction of the inner hole 120, such as Figure 1 As shown, the first wall surface 111 and the second wall surface 112 are arranged in sequence from the front side to the rear side of the rigid wheel 100. The inner tooth portion 113 is arranged on the first wall surface 111, and the inner tooth portion 113 specifically includes a plurality of inner teeth, which are arranged along the circumference of the first wall surface 111. When the flexible wheel 200 is installed in the inner hole 120, the inner tooth portion 113 can mesh with the outer tooth portion 211 of the flexible wheel 200.

[0044] It can be understood that the number of internal teeth of the rigid wheel 100 is greater than the number of external teeth of the flexible wheel 200, and the pitch circle diameter of the rigid wheel 100 is slightly larger than that of the flexible wheel 200. When the wave generator 300 is in operation, the flexible wheel 200 can undergo periodic elastic deformation to form an elliptical shape. During this deformation process, the external teeth of the flexible wheel 200 at both ends of the long axis direction mesh with the internal teeth of the rigid wheel 100, and the teeth in the short axis direction are disengaged. With the continuous rotation of the wave generator 300, the meshing state of the flexible wheel 200 and the internal gear will continue to change, thereby driving the flexible wheel 200 to rotate at a low speed relative to the rigid wheel 100.

[0045] Reference Figure 1 and Figure 2As shown, in the embodiment of the utility model, the inner diameter of the second wall surface 112 is greater than the inner diameter of the first wall surface 111. It can be understood that the inner hole 120 is divided into two sections of hole walls along its front-to-back direction, the aperture of the front section of the inner hole 120 is the inner diameter of the first wall surface 111, and the aperture of the rear section of the inner hole 120 is the inner diameter of the second wall surface 112. In other words, the inner hole 120 has two sections of hole walls with different apertures. Since the first wall surface 111 and the second wall surface 112 are not on the same inner wall surface, a step surface 114 is constructed between the second wall surface 112 and the first wall surface 111, so that the first wall surface 111 and the second wall surface 112 are transitionally connected through the step surface 114.

[0046] In the radial direction of the rigid wheel 100, the distance between the second wall surface 112 and the central axis P of the rigid wheel 100 is greater than that between the first wall surface 111 and the second wall surface 112. The step surface 114 and the second wall surface 112 cooperate with the inner wall of the inner hole 120 to define a recessed space 121. Figure 1 As shown, the recessed space 121 is formed on the inner wall of the inner hole 120 and is annular, the bottom wall of the recessed space 121 is the first wall surface 111, the side wall on one side is the step surface 114, and the other side is an open structure, which is conducive to the lubricating oil to be added to the recessed space 121. Since the first wall surface 111 and the second wall surface 112 are arranged in sequence along the axial direction, the recessed space 121 is adjacent to the inner tooth portion 113, and the recessed space 121 is used to fill the lubricating oil, which can improve the wear problem between the rigid wheel 100 and the flexible wheel 200.

[0047] It should be noted that, in the related art, the inner wall of the inner hole 120 of the rigid wheel 100 is annular and does not have a segmented hole wall structure. The inner tooth portion 113 can cover part of the hole wall, or the inner tooth portion 113 can cover the entire hole wall. Since the inner wall is at the same distance from the central axis P of the rigid wheel 100, and after the flexible wheel 200 is installed in the inner hole 120, the gap between the rigid wheel 100 and the flexible wheel 200 is small, the space that can be filled with lubricating oil is limited, which reduces the lubrication performance. Moreover, the lubricating oil mostly used in the harmonic reducer 10 is grease. Due to the poor fluidity of grease, when the harmonic reducer 10 is subjected to harsh working conditions such as impact torque, there is a problem of insufficient lubrication of the friction contact surface, thereby increasing the amount of wear, seriously restricting the reliability of the harmonic reducer 10, and even reducing the service life of the harmonic reducer 10.

[0048] In the embodiment of the utility model, the recessed space 121 on the inner wall of the inner hole 120 has the function of storing lubricating oil. Compared with the harmonic reducer in the related art, it has a larger space for filling lubricating oil. When the wave generator 300 drives the flexible wheel 200 to operate, the grease in the recessed space 121 can be continuously added to the gap between the rigid wheel 100 and the flexible wheel 200, thereby improving the lubrication performance between the rigid wheel 100 and the flexible wheel 200. Moreover, by increasing the recessed space 121, the contact between the second wall surface 112 and the flexible wheel 200 can be avoided, which further has the function of reducing the contact area, effectively reducing the risk of wear between the rigid wheel 100 and the flexible wheel 200, thereby improving the reliability of the harmonic reducer 10.

[0049] It should be noted that the recessed space 121 stores a certain amount of lubricating oil, which protects the grease and reduces the risk of the grease being contaminated by the abrasive particles inside the harmonic reducer 10, ensuring that the grease can provide stable lubrication performance. Due to the poor fluidity of the grease, when the harmonic reducer 10 is subjected to harsh working conditions such as impact torque, there is a problem of insufficient lubrication of the friction contact surface. The recessed space 121 can bring in and leave some grease when the flexible wheel 200 and the rigid wheel 100 move relative to each other, playing the role of secondary replenishment of lubricant, thereby effectively improving the wear problem of the flexible wheel 200 and the rigid wheel 100.

[0050] It is understandable that after the rigid wheel 100 is formed, the inner wall of the inner hole 120 is processed to form a recessed space 121 by cutting or other methods; in other embodiments, the rigid wheel 100 and the recessed space 121 can also be integrally formed by casting, stamping or other processes. After the rigid wheel 100 is added with the recessed space 121, it is not only beneficial to increase the space for filling lubricating oil, but also can reduce the metal material for making the rigid wheel 100, which plays a role in weight reduction and is beneficial to reducing the weight of the harmonic reducer 10.

[0051] Reference Figure 2 As shown, it can be understood that the inner tooth portion 113 and the body 110 of the rigid wheel 100 are an integrally formed structure, ensuring that the inner tooth portion 113 is stable and reliable. Since the inner tooth portion 113 is formed on the first wall surface 111, the width of the inner tooth portion 113 is consistent with the width of the first wall surface 111, and the width of the inner tooth portion 113 is specifically set according to the size of the outer tooth portion 211 of the flexible wheel 200, ensuring that the inner tooth portion 113 and the outer tooth portion 211 are stably meshed.

[0052] In the embodiment of the utility model, along the axial direction of the inner hole 120, the width of the second wall surface 112 is greater than or equal to the width of the first wall surface 111, so that the recessed space 121 can be ensured to have a sufficiently large size so as to be filled with sufficient lubricating oil. Since the width of the inner tooth portion 113 is consistent with the width of the first wall surface 111, when the first wall surface 111 is equal to the second wall surface 112, the width of the inner tooth portion 113 is equal to the width of the second wall surface 112. Therefore, the width of the inner tooth portion 113 can be equal to half of the width of the inner hole 120, or the width of the inner tooth portion 113 can be less than half of the width of the inner hole 120, ensuring that the size distribution of the inner tooth portion 113 and the recessed space 121 is reasonable. For example, the axial width of the inner hole 120 is 30mm, the width of the first wall surface 111 and the width of the second wall surface 112 can be set to 15mm; for another example, the width of the first wall surface 111 can be set to 18mm, and the width of the second wall surface 112 can be set to 22mm.

[0053] Without changing the overall size of the rigid wheel 100, if the width of the first wall 111 is greater than that of the second wall 112, the inner tooth portion 113 occupies a larger area of ​​the inner wall of the inner hole 120. When the width of the second wall 112 is too narrow, the size of the recessed space 121 becomes too small, which reduces the amount of lubricating oil filled therein, thereby reducing the lubrication performance, and easily causing poor lubrication between the rigid wheel 100 and the flexible wheel 200.

[0054] Reference Figure 2 As shown, in some embodiments, along the axial direction of the inner hole 120, the width of the body 110 is a, and the width of the second wall 112 is b, satisfying: a*50%≤b≤a*60%, that is, the width of the second wall 112 is greater than or equal to 50% of the width of the body 110, and less than or equal to 60% of the width of the body 110, so as to avoid the width of the second wall 112 being too large and causing the recessed space 121 to be too large; when b>a*60%, it means that the second wall 112 occupies a larger overall width of the body 110. At this time, the recessed space 121 is too large, and the size of the inner tooth portion 113 will be too small to affect its contact with the outer tooth portion 211, and the contact area of ​​the tooth surfaces of the two is reduced, thereby affecting the stability of the meshing. The unstable meshing state will increase the vibration and impact in the transmission process, reduce the transmission efficiency, and the load-bearing capacity and transmission performance will also decrease. It will also reduce the overall strength of the rigid wheel 100 and affect the reliability of the harmonic reducer 10.

[0055] It can be understood that when b=a*50%, it means that the width of the second wall 112 is equal to half the width of the main body 110; when b<a*50%, it means that the width of the second wall 112 is less than half the width of the main body 110. At this time, the size of the recessed space 121 is too small, that is, the space for filling the lubricating oil is too small, which can easily cause insufficient lubricating oil and reduce the lubrication performance.

[0056] Reference Figure 1 and Figure 2 As shown, along the radial direction of the inner hole 120, the distance between the first wall 111 and the second wall 112 is h, and the outer diameter of the body 110 is D, which satisfies: D*5%≤h≤D*10%, that is, the distance between the first wall 111 and the second wall 112 is greater than or equal to 5% of the outer diameter of the body 110, and less than or equal to 10% of the outer diameter of the body 110. The distance between the first wall 111 and the second wall 112 can be understood as the depth of the recessed space 121 along the radial direction of the rigid wheel 100. The distance between the first wall 111 and the second wall 112 is also the height difference between the two. The greater the height difference, the greater the depth of the recessed space 121. Under the condition of satisfying D*5%≤h≤D*10%, the depth of the recessed space 121 can meet the requirement of filling enough lubricating oil and provide better lubrication performance. For example, the outer diameter of the body 110 is 50mm, and the depth of the recessed space 121 is h= D*8%=4mm.

[0057] It can be understood that when h<D*5%, it means that the depth of the recessed space 121 is too small, which is not conducive to storing lubricating oil, and the amount of lubricating oil is too small to provide a stable lubrication effect; when h>D*10%, it means that the depth of the recessed space 121 is too large, resulting in a too small distance between the second wall surface 112 and the outer peripheral wall of the body 110, that is, although the size of the recessed space 121 is enlarged, the bottom wall thickness of the recessed space 121 will be too small, reducing the structural strength of the body 110 and the reliability of the harmonic reducer 10. The depth of the recessed space 121 is specifically set according to the use requirements of the harmonic reducer 10, the outer diameter of the rigid wheel 100, the wall thickness of the body 110 and other parameters.

[0058] Reference Figure 2 As shown, the first wall 111 and the second wall 112 are transitionally connected via a step surface 114, wherein the second wall 112 is extended along the axial direction of the inner hole 120, and the step surface 114 is arranged along the radial direction of the inner hole 120. The step surface 114 can be perpendicular to the first wall 111, or the step surface 114 can be inclined along the radial direction, and the angle β between the second wall 112 and the step surface 114 is in the range of 90° to 150°, that is, 90°≤β≤150°.

[0059] exist Figure 2In the cross-sectional view of the body 110 shown, the step surface 114 is perpendicular to the second wall surface 112, and the angle β between the step surface 114 and the second wall surface 112 is 90°. The cross-sectional contour lines of the step surface 114 and the second wall surface 112 are L-shaped, which is convenient for processing and forming the recessed space 121. For example, the inner wall of the inner hole 120 is milled along the axial direction of the body 110 by a milling cutter at one end of the body 110, so as to process and form the recessed space 121. In other embodiments, the angle β between the step surface 114 and the second wall surface 112 may be greater than 90°, for example, the angle β may be 95°, 100°, 120°, etc.

[0060] It should be noted that the step surface 114 can be set as an inclined surface along the radial direction of the inner hole 120, so that the angle β between the step surface 114 and the second wall surface 112 is greater than 90°, which helps the lubricating oil flow along the step surface 114 toward the flexible wheel 200 and improves the lubrication effect. In some embodiments, the angle β between the step surface 114 and the second wall surface 112 does not exceed 150° to avoid the angle being too large and affecting the structure of the inner tooth portion 113. For example, when the angle β between the step surface 114 and the second wall surface 112 is 160°, the length of the step surface 114 will be too large, resulting in the width of the inner tooth portion 113 being too small, resulting in the contact area between the inner tooth portion 113 and the outer tooth portion 211 being too small, and the reliability is reduced.

[0061] Reference Figure 3 As shown, the embodiment of the utility model further provides a harmonic reducer 10, which is suitable for industrial robots, automation devices and other equipment. The harmonic reducer 10 includes a rigid wheel 100, a flexible wheel 200 and a wave generator 300, wherein the rigid wheel 100 adopts the rigid wheel structure of the above embodiment, the flexible wheel 200 is installed in the inner hole 120 of the rigid wheel 100, and the wave generator 300 is installed on the inner side of the flexible wheel 200, and the wave generator 300 is configured to make the outer tooth portion 211 mesh with the inner tooth portion 113 when rotating.

[0062] Reference Figure 2 and Figure 4As shown, along the axial direction of the rigid wheel 100, the maximum width of the inner tooth portion 113 is c, and the maximum width of the outer tooth portion 211 is d, satisfying: d*80%≤c≤d*100%, the maximum width c of the inner tooth portion 113 is greater than or equal to 80% of the maximum width d of the outer tooth portion 211, and less than or equal to 100% of the maximum width d of the outer tooth portion 211, ensuring that the inner tooth portion 113 and the outer tooth portion 211 can be stably meshed. It can be understood that the maximum width c of the inner tooth portion 113 does not exceed the maximum width d of the outer tooth portion 211. When c=d*100%, it means that the maximum width of the inner tooth portion 113 is consistent with that of the outer tooth portion 211. For example, when the maximum width d of the outer tooth portion 211 is 20 mm, the maximum width c of the inner tooth portion 113 can be 20 mm, or c=d*90%=18 mm, and the maximum width of the inner tooth portion 113 is not less than 16 mm.

[0063] It can be understood that when c<d*80%, it means that the maximum width c of the inner tooth portion 113 is less than 80% of the maximum width d of the outer tooth portion 211. The width difference between the inner tooth portion 113 and the outer tooth portion 211 is large, which is not conducive to maintaining the stability of the meshing area. The tooth surface contact area of ​​the two is uneven, and the stress distribution is also uneven, which accelerates the wear and fatigue damage of the tooth surface, reduces the load-bearing capacity and service life, and thus reduces the reliability of the operation of the harmonic reducer 10.

[0064] Reference Figure 4 As shown, in the embodiment of the utility model, the flexible wheel 200 includes a barrel 210 and a connecting portion 220, the barrel 210 is cylindrical, the external tooth portion 211 is arranged on the outer peripheral wall of one end of the barrel 210, the connecting portion 220 is arranged at the other end of the barrel 210, the wave generator 300 is installed on the inner side of the barrel 210, and the connecting portion 220 is used to connect the output assembly 400. The external tooth portion 211 includes a plurality of external teeth, and the plurality of external teeth are arranged along the circumference of the barrel 210. The barrel 210 is a thin-walled structure, and can be deformed under the action of the wave generator 300.

[0065] During the operation of the harmonic reducer 10, the wave generator 300 forces the flexible spline 200 to produce elastic deformation and become elliptical when in operation. The flexible spline 200 is completely meshed with the rigid wheel 100 in the direction of the major axis of the ellipse and completely separated in the direction of the minor axis. The remaining teeth are either in a meshing state or in a meshing state depending on the rotation position of the flexible spline 200. With the continuous rotation of the wave generator 300, the meshing state of the flexible spline 200 and the rigid wheel 100 will continue to change, forming a meshing-in and meshing-out zone, thereby realizing the relative deceleration motion between the flexible spline 200 and the rigid wheel 100.

[0066] Reference Figure 3As shown, the wave generator 300 includes a flexible bearing 310 and a cam 320. The flexible bearing 310 is sleeved on the cam 320. The flexible bearing 310 is a thin-walled bearing that can be elastically deformed. The cam 320 is used to connect a driving device such as a motor. Taking the motor as an example, when the motor drives the cam 320 to rotate, the flexible bearing 310 is deformed regularly with the rotation of the cam 320, thereby forcing the flexible wheel 200 to deform repeatedly, thereby driving the flexible wheel 200 to rotate at a low speed in the opposite direction of the wave generator 300 relative to the rigid wheel 100.

[0067] It is understandable that the flexible wheel 200 is generally used as the output component of the harmonic reducer 10. Through the rotation of the flexible wheel 200, the harmonic gear device can convert the input motion of the wave generator 300 into the output motion of the flexible wheel 200, thereby realizing the transmission and reduction of power. Figure 3 and Figure 4 As shown, the harmonic reducer 10 further includes an output assembly 400, which is connected to the connection portion 220 of the flexible wheel 200. Specifically, one end of the barrel 210 away from the outer tooth portion 211 is bent inward to form the connection portion 220, which is roughly disc-shaped, and a flange portion 230 is provided in the middle of the connection portion 220. The flange portion 230 is provided with a plurality of mounting holes, which are arranged along the circumference of the flange portion 230. The flange portion 230 is connected to the output assembly 400 through the mounting holes by fasteners such as bolts, so as to transmit power from the flexible wheel 200 to the output component. The output assembly 400 is used to connect other devices to transmit motion and torque to other devices. For example, the output assembly 400 is connected to the mechanical arm of an industrial robot, so as to drive the mechanical arm to move to perform corresponding operations.

[0068] In other embodiments, the connecting portion 220 can be bent in a direction away from the central axis P of the barrel 210, so that the connecting portion 220 is annular and arranged around the outer wall of the barrel 210. The flange portion 230 is formed circumferentially on the connecting portion 220 and is connected to the output assembly 400 through the flange portion 230.

[0069] Reference Figure 3 As shown, it can be understood that the outer peripheral wall of the rigid wheel 100 is provided with a boss 130, and the boss 130 is provided with a first connecting hole 131 arranged along the axial direction. The output assembly 400 includes a fixed part 410 and a rotating part 420, the fixed part 410 is annular, and the rotating part 420 is installed on the inner side of the rotating part 420. The rotating part 420 is connected to the flange part 230, and the fixed part 410 is provided with a second connecting hole 411. The first connecting hole 131 of the rigid wheel 100 and the second connecting hole 411 of the fixed part 410 are connected by connecting bolts 600, so that the rigid wheel 100 and the fixed part 410 cooperate to form a fixing part, and the flexible wheel 200 is connected to the rotating part 420 and can rotate relative to the rigid wheel 100 and the fixed part 410.

[0070] In some embodiments, the output assembly 400 may be a bearing structure, wherein the fixed portion 410 is the outer ring of the bearing structure, and the rotating portion 420 is the inner ring of the bearing structure. Of course, the specific form of the output assembly 400 can be selected according to the requirements of the actual application.

[0071] by Figure 3 The axial direction shown is used as a reference direction, the rigid wheel 100, the flexible wheel 200 and the wave generator 300 are axially located at the front side of the output assembly 400, the inner tooth portion 113 is located on the inner wall of the front end of the rigid wheel 100, the second wall surface 112 is located on the inner wall of the rear end of the rigid wheel 100, the wave generator 300 is close to the front end opening of the flexible wheel 200, and the open end of the recessed space 121 along the axial direction is arranged toward the output assembly 400.

[0072] Reference Figure 3 and Figure 5 As shown, since the cylinder 210 is arranged along the axial direction of the rigid wheel 100 toward the rear side and close to the output assembly 400, when the flexible wheel 200, the rigid wheel 100 and the output assembly 400 are installed in place, an annular groove 500 is defined between the outer wall of the cylinder 210, the second wall surface 112 and the step surface 114, and the annular groove 500 is arranged around the cylinder 210.

[0073] It can be understood that, since the recessed space 121 is filled with lubricating oil, and the side of the recessed space 121 facing the barrel 210 is an open structure, the lubricating oil can expand into the annular groove 500. During the operation of the harmonic reducer 10, the flexible wheel 200 can continuously take away the lubricating oil when it rotates. Since the annular groove 500 is connected to the meshing area between the rigid wheel 100 and the flexible wheel 200, the lubricating oil can be supplemented to the meshing area between the rigid wheel 100 and the flexible wheel 200 through the annular groove 500, thereby effectively improving the lubrication effect and solving the wear problem between the flexible wheel 200 and the rigid wheel 100.

[0074] Through experimental comparison, compared with the traditional harmonic reducer, the harmonic reducer 10 of the embodiment of the utility model has a recessed space 121 added to the inner wall of the rigid wheel 100, so that the inner side of the rigid wheel 100 has more space for filling lubricating oil. Without changing the outer dimensions of the rigid wheel 100 and the flexible wheel 200, the lubrication performance between the rigid wheel 100 and the flexible wheel 200 is effectively improved, and the risk of wear between the rigid wheel 100 and the flexible wheel 200 is reduced. The reliability of the operation of the harmonic reducer 10 can be improved by more than 10%, and the friction noise is also reduced; and the metal material used to make the rigid wheel 100 can be reduced, which plays a role in weight reduction and is conducive to reducing the weight of the harmonic reducer 10.

[0075] The present utility model also provides an industrial robot, comprising the harmonic reducer 10 shown in the above embodiment. Figures 1 to 5 As shown, in the embodiment of the utility model, the inner peripheral wall of the inner hole 120 of the rigid wheel 100 is provided with a first wall surface 111 and a second wall surface 112, both of which are annular and arranged in sequence along the axial direction of the inner hole 120, and the inner diameter of the second wall surface 112 is greater than the inner diameter of the first wall surface 111. Since the first wall surface 111 and the second wall surface 112 are not on the same inner wall surface, a step surface 114 is constructed between the second wall surface 112 and the first wall surface 111, so that the first wall surface 111 and the second wall surface 112 are transitionally connected through the step surface 114. The step surface 114 and the second wall surface 112 cooperate with the inner wall of the inner hole 120 to define a recessed space 121, which is formed on the inner wall of the inner hole 120 and is annular, and the recessed space 121 has the function of storing lubricating oil.

[0076] Compared with the traditional harmonic reducer, the harmonic reducer 10 of the embodiment of the utility model has a larger space for filling lubricating oil. When the wave generator 300 drives the flexible wheel 200 to operate, the grease in the recessed space 121 can be continuously added to the gap between the rigid wheel 100 and the flexible wheel 200, thereby improving the lubrication performance between the rigid wheel 100 and the flexible wheel 200. Moreover, by increasing the recessed space 121, the contact between the second wall surface 112 and the flexible wheel 200 can be avoided, which further has the effect of reducing the contact area, effectively reducing the risk of wear between the rigid wheel 100 and the flexible wheel 200, thereby improving the reliability of the harmonic reducer 10.

[0077] The industrial robot in the embodiment of the utility model can specifically be an automated device including a robotic arm. A motor and a harmonic reducer 10 for driving the movement of the robotic arm can be provided at each joint of the robotic arm. The harmonic reducer 10 is connected to the motor, and the motor drives the harmonic reducer 10 to transmit and reduce power, thereby driving the movement of the robotic arm.

[0078] Since the industrial robot includes the harmonic reducer 10 of the above embodiment, it at least has the beneficial effects of the above harmonic reducer 10, which will not be described in detail here.

[0079] Of course, the present invention is not limited to the above-mentioned embodiments, and technicians familiar with the field may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A rigid wheel, characterized in that: include: The main body has an inner hole. Along the axial direction of the inner hole, the inner circumferential wall of the inner hole is sequentially provided with a first wall surface and a second wall surface, the first wall surface is formed with an inner tooth portion, and the inner tooth portion is arranged along the circumference of the first wall surface, the inner diameter of the second wall surface is larger than the inner diameter of the first wall surface, and the second wall surface and the first wall surface are configured as a step surface, and the step surface and the second wall surface define a recessed space for filling lubricating oil.

2. The rigid wheel according to claim 1, characterized in that: Along the axial direction of the inner hole, the width of the second wall surface is greater than or equal to the width of the first wall surface.

3. The rigid wheel according to claim 2, characterized in that: Along the axial direction of the inner hole, the width of the body is a, and the width of the second wall surface is b, satisfying: a*50%≤b≤a*60%.

4. The rigid wheel according to claim 1, characterized in that: Along the radial direction of the inner hole, the distance between the first wall surface and the second wall surface is h, and the outer diameter of the body is D, satisfying: D*5%≤h≤D*10%.

5. The rigid wheel according to claim 1, characterized in that: The included angle between the second wall surface and the step surface ranges from 90° to 150°.

6. A harmonic reducer, characterized in that: include: The rigid wheel according to any one of claims 1 to 5; A flexible wheel, provided with an external tooth portion, the flexible wheel being mounted in the inner hole; A wave generator is installed on the inner side of the flexible wheel, and the wave generator is configured to make the outer tooth portion mesh with the inner tooth portion when rotating.

7. The harmonic reducer according to claim 6, characterized in that: Along the axial direction of the rigid wheel, the maximum width of the inner tooth portion is c, and the maximum width of the outer tooth portion is d, satisfying: d*80%≤c≤d*100%.

8. The harmonic reducer according to claim 6, characterized in that: The flexible wheel includes a cylinder portion, the external tooth portion is formed on a portion of the outer peripheral wall of the cylinder portion, and the cylinder portion is arranged along the axial direction of the rigid wheel toward the second wall surface, so that an annular groove is defined between the outer wall of the cylinder portion, the second wall surface and the step surface.

9. The harmonic reducer according to claim 8, characterized in that: The harmonic reducer also includes an output assembly, a connecting portion is provided at one end of the cylinder away from the external tooth portion, the output assembly is connected to the connecting portion, and the second wall surface is formed at one end of the rigid wheel facing the output assembly.

10. An industrial robot, characterized in that: Including the harmonic reducer as described in any one of claims 6 to 9.

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