Cup type flexible wheel and harmonic reducer

Abstract

This application relates to a cup-shaped flexspline and a harmonic reducer. The cylinder body and the bottom plate of the flexspline are connected by a first arc section. The tooth ring is arranged at one end of the cylinder body away from the bottom plate. The tooth ring includes a plurality of first teeth. The tooth ring is connected to the cylinder body at the connection point. The line connecting the pole point of the outer contour line of the cylinder body and the connection point is perpendicular to the tangent at the connection point. The polar radius ρ(θ) of the outer contour line of the cylinder body satisfies ρ(θ) = U1 + U2θ + U3θ 2 , (0 ≤ θ ≤ π / 2), where U1 is the distance between the pole point of the outer contour line of the cylinder body and the connection point, U2 is positively correlated with w0 and negatively correlated with m, m is the module of the first teeth, w0 is the maximum radial deformation of the theoretical design section of the tooth ring, and U3 is positively correlated with L1. L1 is the length from the end of the tooth ring away from the bottom plate to the side of the maximum wall thickness of the bottom plate away from the tooth ring. According to the flexspline of the present invention, the cylinder body causes the first teeth to translate under the action of the wave generator without generating taper deformation.

Description

Technical Field

[0001] The present application relates to the field of robots, and in particular to a cup-type flexspline and a harmonic reducer. Background Art

[0002] Harmonic reducers have the characteristics of high transmission accuracy and small size, and are currently widely used in joint modules of bionic robots and industrial robots. Harmonic reducers are usually composed of a flexible wheel, a rigid wheel and a wave generator, in which the flexible wheel is an elastic component that produces periodic elastic deformation under the action of the wave generator, and the deformation causes the first flexible wheel teeth and the first rigid wheel teeth to mesh, thereby realizing the transmission of motion and force.

[0003] Due to the structural characteristics of the cup-type flexible wheel, the flexible wheel produces a taper deformation along the axial generatrix under the action of the wave generator, which causes interference in the front section along the first tooth width of the flexible wheel and the rear section does not participate in the meshing. The meshing width along the tooth width becomes shorter, and the meshing pressure on the tooth surface becomes larger, aggravating the wear of the flexible wheel and the rigid wheel, thereby affecting the transmission accuracy and service life of the harmonic reducer.

[0004] CN112762157A proposes a cup-shaped flexible wheel with a gradually changing wall thickness. This structure cannot solve the problem of tapered deformation of the flexible wheel along the axial generatrix. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a cup-type flexible wheel, which can prevent the tooth ring of the flexible wheel from producing a taper deformation along the axial generatrix, so that the full tooth width of the first gear tooth of the flexible wheel in the tooth width direction can participate in the meshing, thereby improving the precision retention of the flexible wheel.

[0006] The present invention also proposes a harmonic reducer, including the above-mentioned flexible wheel, which can increase the service life of the entire harmonic reducer.

[0007] According to the cup-type flexible wheel of the present invention, the gear ring comprises a gear ring, a cylinder, a bottom plate and a first arc segment, the cylinder and the bottom plate are connected by the first arc segment, the gear ring is arranged at one end of the cylinder away from the bottom plate, the gear ring comprises a plurality of first gear teeth, a side of the bottom plate away from the gear ring is provided with an outwardly convex output portion, the gear ring is connected to the cylinder at a connection point, a line between the pole of the outer contour line of the cylinder and the connection point is perpendicular to the tangent at the connection point and is located outside the cylinder, and the pole diameter ρ(θ) of the outer contour line of the cylinder satisfies the formula: ρ(θ)=U1+U2θ+U3θ 2 , (0≤θ≤π / 2), where θ is the polar angle, U1 is the distance from the pole of the outer contour of the cylinder to the connection point, U2 is positively correlated with w0 and negatively correlated with m, m is the module of the first gear tooth, w0 is the maximum radial deformation of the theoretical design section of the gear ring, U3 is positively correlated with L1, and L1 is the length from the end face of the gear ring to the side of the maximum wall thickness of the bottom plate away from the gear ring.

[0008] According to the cup-type flexible wheel of the present invention, the outer contour of the cylinder enables the cylinder to translate the gear ring under the action of the wave generator without generating conical deformation, thereby increasing the axial effective meshing line length of the first gear tooth and reducing the pressure caused by the meshing force on the first gear tooth under the condition of transmitting the same torque, thereby reducing the wear of the first gear tooth during the transmission process and extending the time for maintaining the transmission accuracy.

[0009] According to the cup-type flexible gear of the present invention, the gear ring also includes a second arc segment, the second arc segment connects the first gear teeth and the cylinder respectively, the second arc segment and the cylinder are connected at a connection point, the radius of the connection point in the radial direction of the cylinder is r1, and U1 satisfies 100 / 56<U1 / r1<100 / 9.

[0010] Optionally, U2 satisfies w0 / 35m<U2<w0 / 10m.

[0011] Optionally, U3 satisfies L1 / 100<U3<L1 / 10.

[0012] Optionally, L1 satisfies 4.0<L1 / r1<5.6, and / or the width of the gear ring along the axial direction is b, and b satisfies 1.8<b / r1<2.4.

[0013] Optionally, the first arc segment includes a first end connected to the cylinder and a second end connected to the bottom plate, the outer wall at the first end is tangent to the outer wall of the cylinder, and the outer wall at the second end is tangent to the outer wall of the bottom plate, the radius corresponding to the outer wall contour of the first arc segment is r2, r2 satisfies 0.1<r2 / r1<0.8, and / or the radius corresponding to the outer wall contour of the output part is r4, r4 satisfies 0.1<r4 / r1<1.3.

[0014] Optionally, ρ(π / 2)>L1-b.

[0015] According to the cup-type flexible impeller of the present invention, the cylinder and the first arc segment are both structures with equal wall thickness, the wall thickness of the cylinder is t1, the wall thickness of the first arc segment is t2, the bottom plate is a variable wall thickness structure, the wall thickness of the bottom plate at the thinnest part is t3, and the wall thickness of the connection between the bottom plate and the output part in the radial direction is t4, wherein t1, t2, t3 and t4 satisfy: t4>t1=t2>t3.

[0016] Optionally, a first straight line is defined, the distance between the first straight line and the end of the gear ring away from the bottom plate is L1, the first straight line intersects with the extension line of the outer contour of the cylinder at a first point, the point where the outer contour of the bottom plate and the output part meet is a second point, the point where the perpendicular bisector of the line between the first point and the second point intersects with the bottom plate is a third point, and the wall thickness at the third point is t3.

[0017] The harmonic reducer according to the present invention comprises: an annular rigid internal gear; a cup-type flexspline as described above, the flexspline partially meshing with the internal gear; and a wave generator, the wave generator being clamped in the flexspline.

[0018] According to the harmonic reducer of the present invention, the outer contour of the cylinder of the flexible wheel allows the cylinder to cause the gear ring to translate under the action of the wave generator without causing taper deformation, thereby increasing the axial effective meshing line length of the first gear tooth, and reducing the pressure caused by the meshing force on the first gear tooth under the condition of transmitting the same torque, thereby reducing the wear of the first gear tooth during the transmission process, extending the maintenance time of the transmission accuracy, and thus extending the overall life of the harmonic reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 is an overall structural diagram of a harmonic reducer according to an embodiment of the present invention;

[0022] Figure 2 for Figure 1 Sectional view in the middle II direction;

[0023] Figure 3 for Figure 1 Cross-section along the mid-JJ direction;

[0024] Figure 4 FIG. 4 is a cross-sectional view of a flexible spline according to an embodiment of the present invention.

[0025] Reference numerals:

[0026] Flexspline 1, gear ring 101, gear ring end face 1011, second arc segment 1012, cylinder 102, cylinder outer contour line 1021, first arc segment 103, first arc segment outer contour 1031, bottom plate 104, bottom plate outer wall 1041, bottom plate inner wall 1042, output part 105, output part outer wall contour 1051, axis line 106, wave generator 2, cam 201, flexible bearing 202, internal gear 3, second gear teeth 301, first straight line 107. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0028] like Figure 1 As shown, the cup-type flexspline 1 of the present invention can be applied to a harmonic reducer 100. In some embodiments, the harmonic reducer 100 includes: an annular rigid internal gear 3; as the cup-type flexspline 1 mentioned above, the flexspline 1 is partially meshed with the internal gear 3; and a wave generator 2, which is clamped in the flexspline 1.

[0029] like Figure 1 As shown, usually, the wave generator 2 includes a cam 201 and a flexible bearing 202, the inner side of the inner gear 3 is provided with a second gear 301, the bearing 202 is sleeved on the outer side of the cam 201, the inner gear 3 is sleeved on the outer side of the flexible wheel 1, and the second gear 301 is meshed with the first gear. Usually, the inner gear 3 is fixed, and the wave generator 2 forces the flexible wheel 1 to continuously deform when rotating. The first gear gradually meshes with the second gear 301 during the deformation process of the flexible wheel 1, and then gradually withdraws until it is completely disengaged. The first gear repeats the cycle of meshing, meshing, meshing out and disengaging in the deformation process of the flexible wheel 1. This staggered tooth movement converts the input of the wave generator 2 into the output of the flexible wheel 1, thereby realizing the reduction transmission.

[0030] The cup-type flexspline 1 used in the harmonic reducer 100 is described below with reference to the accompanying drawings.

[0031] like Figure 4 As shown, the cup-type flexible spline 1 according to the embodiment of the present invention includes a gear ring 101 , a cylinder 102 , a bottom plate 104 and a first arc segment 103 .

[0032] Specifically, the cylinder 102 and the bottom plate 104 are connected by a first arc segment 103, the gear ring 101 is arranged at one end of the cylinder 102 away from the bottom plate 104, the gear ring 101 includes a plurality of first gear teeth, and a side of the bottom plate 104 away from the gear ring 101 is provided with a convex output portion 105, the gear ring 101 and the cylinder 102 are connected at a connection point C, the line between the pole of the outer contour line of the cylinder and the connection point C is perpendicular to the tangent at the connection point C, and is located outside the cylinder 102, and the pole diameter ρ(θ) of the outer contour line of the cylinder satisfies the formula: ρ(θ)=U1+U2θ+U3θ 2, (0≤θ≤π / 2), where θ is the polar angle, U1 is the distance from the pole of the outer contour of the cylinder to the connection point C, U2 is positively correlated with w0 and negatively correlated with m, m is the module of the first gear tooth, w0 is the maximum radial deformation of the theoretical design section of the gear ring 101, U3 is positively correlated with L1, and L1 is the length from the end face 1011 of the gear ring to the maximum wall thickness on the side of the bottom plate 104 away from the gear ring 101.

[0033] To elaborate, when the flexible wheel 1 is acted upon by the wave generator 2, U1 and U3 affect the deformation of the cylinder 102 and ultimately affect the displacement of the first gear tooth. U2 is positively correlated with w0, and the larger w0 is, the larger U2 is. U2 is negatively correlated with m, and the larger m is, the smaller U2 is. U2 affects the displacement of the first gear tooth, so that the deformation of the cylinder 102 can drive the first gear tooth to translate without causing taper deformation, thereby reducing the wear of the first gear tooth during the transmission process and extending the transmission accuracy retention time.

[0034] It should be noted that “L1 is the length from the gear ring end face 1011 to the maximum wall thickness on the side of the bottom plate 104 away from the gear ring 101”, that is, L1 is the sum of the length from the gear ring end face 1011 to the inner wall of the bottom plate 104 and the maximum wall thickness of the bottom plate 104 .

[0035] According to the cup-type flexible wheel 1 of the embodiment of the present invention, the outer contour of the cylinder 102 allows the cylinder 102 to translate the gear ring 101 under the action of the wave generator 2 without causing conical deformation, so that the axial effective meshing line length of the first gear tooth is increased, and the pressure caused by the meshing force on the first gear tooth is reduced under the condition of transmitting the same torque, thereby reducing the wear of the first gear tooth during the transmission process and extending the time for maintaining the transmission accuracy.

[0036] like Figure 4 As shown, according to the cup-type flexible spline 1 of the embodiment of the present invention, the gear ring 101 also includes a second arc segment 1012, the second arc segment 1012 connects the first gear tooth and the cylinder 102 respectively, the second arc segment 1012 and the cylinder 102 are connected at a connection point C, the radius of the connection point C in the radial direction of the cylinder 102 is r1, and U1 satisfies 100 / 56<U1 / r1<100 / 9.

[0037] According to the cup-type flexible spline 1 of the embodiment of the present invention, the second arc segment 1012 is provided to ensure the structural strength of the connection between the ring gear 101 and the cylinder 102, and ensure the structural stability and service life of the flexible spline 1. When the size of r1 is constant, if the value of U1 is too large, the ring gear 101 is likely to be tapered in the tooth width direction. If the value of U1 is too small, stress concentration will be likely to occur at the first arc segment 103, increasing the fatigue stress of the flexible spline 1 during operation. Therefore, it is necessary to set a suitable size of U1.

[0038] That is, U1 satisfies: 100 / 56r1<U1<100 / 9r1, where U1 can be 100 / 50r1, 100 / 45r1, 100 / 40r1, 100 / 35r1, 100 / 30r1, 100 / 25r1, 100 / 20r1, 100 / 15r1, 100 / 10r1, etc. The units of U1 and r1 are both mm.

[0039] In some embodiments, U2 satisfies w0 / 35m<U2<w0 / 10m.

[0040] According to the cup-type flexible spline 1 of the embodiment of the present invention, when w0 and m are constant, if the value of U2 is too large, the gear ring 101 will be tapered in the tooth width direction, which will easily cause stress concentration at the first arc segment 103 and increase the fatigue stress of the flexible spline 1 during operation. Therefore, it is necessary to set a suitable value of U2.

[0041] For example, U2 can be w0 / 34m, w0 / 33m, w0 / 32m, w0 / 31m, w0 / 30m, w0 / 29m, w0 / 28m, w0 / 27m, w0 / 26m, w0 / 25m, w0 / 24m, w0 / 23m, w0 / 22m, w0 / 21m, w0 / 20m, w0 / 19m, w0 / 18m, w0 / 17m, w0 / 16m, w0 / 15m, w0 / 14m, w0 / 13m, w0 / 12m and w0 / 11m, etc. The units of U2 and w0 are both mm.

[0042] In some embodiments, U3 satisfies L1 / 100<U3<L1 / 10. If the value of U3 is too large, it is easy to generate excessive stress on the bottom plate 104 and cause damage to the bottom plate 104. If the value of U3 is too small, it is easy to generate stress concentration at the first arc segment 103 and cause damage to the first arc segment 103. Therefore, it is necessary to set a suitable value of U3.

[0043] For example, U3 may be L1 / 95, L1 / 90, L1 / 85, L1 / 80, L1 / 75, L1 / 70, L1 / 65, L1 / 60, L1 / 55, L1 / 50, L1 / 45, L1 / 40, L1 / 35, L1 / 30, L1 / 25, L1 / 20, and L1 / 15, etc. The units of U3 and L1 are both mm.

[0044] In some embodiments, L1 satisfies 4.0<L1 / r1<5.6, that is, L1 satisfies: 4.0r1<L1<5.6r1. When r1 is constant, the smaller L1 is, the more serious the stress concentration at the bottom plate 104 is. The larger L1 is, the greater the overall weight of the flexible wheel 1 is, which affects the manufacturing cost and the overall volume and weight of the harmonic reducer 100. Therefore, it is necessary to set a suitable L1 size. Among them, L1 can be 4.1r1, 4.2r1, 4.3r1, 4.4r1, 4.5r1, 4.6r1, 4.7r1, 4.8r1, 4.9r1, 5.0r1, 5.1r1, 5.2r1, 5.3r1, 5.4r1, and 5.5r1.

[0045] In some embodiments, the width of the gear ring 101 along the axial direction is b, and b satisfies 1.8<b / r1<2.4. That is, b satisfies: 1.8r1<b<2.4r1. b can be 1.9r1, 2.0r1, 2.1r1, 2.2r1 and 2.3r1. If b is too large, the tooth width of the first gear tooth will be too large, and the gear ring 101 will be tapered in the tooth width direction, which will not increase the effective gear tooth meshing width and increase the local wear of the gear teeth. If b is too small, the gear ring 101 can be translated, and the gear teeth will increase the contact pressure generated when the gear teeth are meshed due to the short gear tooth width, resulting in severe wear of the gear teeth. Therefore, it is necessary to set a suitable size of b.

[0046] In some embodiments, the first arc segment 103 includes a first end D connected to the cylinder 102 and a second end E connected to the bottom plate 104. The outer wall at the first end D is tangent to the outer wall of the cylinder 102, and the outer wall at the second end E is tangent to the outer wall of the bottom plate 104. The radius corresponding to the outer wall profile of the first arc segment 103 is r2, and r2 satisfies 0.1<r2 / r1<0.8. In other words, r2 satisfies 0.1r1<r2<0.8r1. When r1 is constant, if r2 is too large, the deformation of the cylinder 102 is not easy to drive the first gear teeth to translate. If r2 is too small, the first arc segment 103 will produce stress concentration and is easy to break. Therefore, setting a suitable r2 size can make the stress at the cylinder 102, the first arc segment 103 and the bottom plate 104 more uniform, and at the same time make the first gear teeth less likely to produce taper deformation. Among them, r2 can be 0.2r1, 0.3r1, 0.4r1, 0.5r1, 0.6r1 and 0.7r1. Figure 4 As shown, the first arc segment outer contour 1031 is tangent to the outer contour line 1021 of the cylinder and the outer wall 1041 of the bottom plate respectively.

[0047] like Figure 4As shown, in some embodiments, the radius corresponding to the outer wall profile 1051 of the output part is r4, and r4 satisfies 0.1<r4 / r1<1.3. That is, r4 satisfies 0.1r1<r4<1.3r1. When r1 is constant, the larger the r4, the higher the structural strength of the output part 105, and at the same time, it is not conducive to the deformation of the bottom plate 104, causing the gear ring 101 to have a taper deformation in the tooth width direction. The smaller the r4, the lower the structural strength of the output part 105, and cannot withstand a large output load. Therefore, it is necessary to set a suitable r4 size. r4 can be 0.2r1, 0.3r1, 0.4r1, 0.5r1, 0.6r1, 0.7r1, 0.8r1, 0.9r1, 1.0r1, 1.1r1, and 1.2r1, etc.

[0048] In some embodiments, ρ(π / 2)>L1-b. Such a configuration makes the outer contour of the cylinder 102 curved, making it easier for the first gear tooth to translate under the action of the wave generator 2.

[0049] like Figure 4 As shown, according to the cup-type flexible wheel 1 of the embodiment of the present invention, the cylinder 102 and the first arc segment 103 are both structures with equal wall thickness, the wall thickness of the cylinder 102 is t1, the wall thickness of the first arc segment 103 is t2, the bottom plate 104 is a variable wall thickness structure, the wall thickness of the bottom plate 104 at the thinnest part is t3, and the wall thickness of the connection between the bottom plate 104 and the output part 105 in the radial direction is t4, wherein t1, t2, t3 and t4 satisfy: t4>t1=t2>t3.

[0050] That is to say, the cylinder 102 and the first arc segment 103 are both configured with equal wall thickness, so that when the flexible wheel 1 is acted upon by the wave generator 2, the stress on the cylinder 102 and the first arc segment 103 can be more evenly distributed, and the bottom plate 104 is a variable wall thickness structure. Such a configuration can make the bottom plate 104 easier to deform, and further prevent stress concentration at the first arc segment 103. Among them, t1, t2, t3 and t4 satisfy: t4>t1=t2>t3, so that when the cylinder 102, the first arc portion and the bottom plate 104 are deformed, the connection between the bottom plate 104 and the output portion 105 has a higher structural strength, and the structural damage of the output portion 105 can be prevented. Among them, the bottom plate inner wall 1042 is a plane structure, and the bottom plate outer wall 1041 is a curved structure, such as Figure 4 As shown, in the cross-sectional view formed by cutting the flexible wheel 1 along the axial direction, the bottom plate inner wall 1042 is in a straight line shape, and the bottom plate outer wall 1041 is in a curved line shape.

[0051] like Figure 4As shown, in some embodiments, a first straight line 107 is defined, the distance between the first straight line 107 and the end face 1011 of the gear ring is L1, the first straight line 107 and the extension line of the outer contour of the cylinder 102 intersect at the first point A, the point where the outer contour of the bottom plate 104 and the output portion 105 meet is the second point B, the point where the perpendicular midline of the line between the first point A and the second point B intersects with the bottom plate 104 is the third point F, and the wall thickness at the third point F is t3. In this way, when the bottom plate 104 is deformed under force, it is easier to drive the first gear to translate, thereby avoiding tapered deformation and making the stress distribution more uniform.

[0052] like Figure 1 As shown, the harmonic reducer 100 according to the embodiment of the present invention comprises: an annular rigid internal gear 3; the cup-type flexspline 1 as mentioned above, the flexspline 1 partially meshing with the internal gear 3; and a wave generator 2, which is clamped in the flexspline 1.

[0053] Figure 2 shows an overall cross-sectional view of the harmonic reducer 100 along the long axis direction of the flexible wheel 1, Figure 3 FIG. 1 shows a cross-sectional view of the entire harmonic reducer 100 along the short axis direction of the flexible wheel 1. Figure 2 As shown in FIG. 1 , after the flexible wheel 1 is deformed, the gear ring 101 of the flexible wheel 1 in the section where the long axis is located is translated as a whole without tapering deformation, and the radial displacement at the long axis is w0, as shown in FIG. Figure 3 As shown in FIG. 1 , after the flexible wheel 1 is deformed, the gear ring 101 of the flexible wheel 1 in the section where the short axis is located is translated as a whole without causing conical deformation. Figure 2 As shown, the cylinder 102, the first arc segment 103 and the bottom plate 104 are deformed in a direction away from the gear ring end surface 1011 along the axis 106 of the flexible wheel 1. Figure 3 As shown, the cylinder 102, the first arc segment 103 and the bottom plate 104 are deformed along the axis 106 of the flexible wheel 1 close to the end surface 1011 of the gear ring. Figure 2 and Figure 3 The dotted lines in the figure are the flexible wheel 1 before deformation, and the solid lines are the flexible wheel 1 after deformation.

[0054] According to the harmonic reducer 100 of the embodiment of the present invention, the outer contour of the cylinder 102 of the flexible wheel 1 allows the cylinder 102 to translate the gear ring 101 under the action of the wave generator 2 without causing conical deformation, so that the axial effective meshing line length of the first gear tooth is increased, and the pressure caused by the meshing force on the first gear tooth is reduced under the condition of transmitting the same torque, thereby reducing the wear of the first gear tooth during the transmission process, extending the maintenance time of the transmission accuracy, and thus extending the service life of the whole harmonic reducer 100.

[0055] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "inner", "outer", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships 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, rather than indicating or implying 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. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. A cup-type flexible wheel, characterized in that: The invention comprises a gear ring, a cylinder, a bottom plate and a first arc segment, wherein the cylinder and the bottom plate are connected by the first arc segment, the gear ring is arranged at one end of the cylinder away from the bottom plate, the gear ring comprises a plurality of first gear teeth, a side of the bottom plate away from the gear ring is provided with an outwardly convex output portion, the gear ring is connected to the cylinder at a connection point, a line between the pole of the outer contour line of the cylinder and the connection point is perpendicular to a tangent line at the connection point and is located outside the cylinder, and the pole diameter ρ(θ) of the outer contour line of the cylinder satisfies the formula: ρ(θ)=U1+U2θ+U3θ 2 , (0≤θ≤π / 2), where θ is the polar angle, U1 is the distance from the pole of the outer contour of the cylinder to the connection point, U2 is positively correlated with w0 and negatively correlated with m, m is the module of the first gear tooth, w0 is the maximum radial deformation of the theoretical design section of the gear ring, U3 is positively correlated with L1, and L1 is the length from the end face of the gear ring to the side of the maximum wall thickness of the bottom plate away from the gear ring.

2. The cup-type flexible wheel according to claim 1, characterized in that: The gear ring also includes a second arc segment, which connects the first gear tooth and the cylinder respectively. The second arc segment and the cylinder are connected at the connection point. The radius of the connection point in the radial direction of the cylinder is r1, and U1 satisfies 100 / 56<U1 / r1<100 / 9.

3. The cup-type flexible wheel according to claim 2, characterized in that: U2 satisfies w0 / 35m<U2<w0 / 10m.

4. The cup-type flexible wheel according to claim 3, characterized in that: U3 satisfies L1 / 100<U3<L1 / 10.

5. The cup-type flexible wheel according to claim 2, characterized in that: L1 satisfies 4.0<L1 / r1<5.6, and / or The width of the gear ring along the axial direction is b, and b satisfies 1.8<b / r1<2.

4.

6. The cup-type flexible wheel according to claim 2, characterized in that: The first arc segment includes a first end connected to the cylinder and a second end connected to the bottom plate, the outer wall at the first end is tangent to the outer wall of the cylinder, the outer wall at the second end is tangent to the outer wall of the bottom plate, the radius corresponding to the outer wall profile of the first arc segment is r2, r2 satisfies 0.1<r2 / r1<0.8, and / or The radius corresponding to the outer wall profile of the output portion is r4, and r4 satisfies 0.1<r4 / r1<1.

3.

7. The cup-type flexible wheel according to claim 6, characterized in that: ρ(π / 2)>L1-b.

8. The cup-type flexible wheel according to claim 1, characterized in that: The cylinder and the first arc segment are both structures with equal wall thickness, the wall thickness of the cylinder is t1, the wall thickness of the first arc segment is t2, the bottom plate is a structure with variable wall thickness, the wall thickness of the bottom plate at its thinnest point is t3, and the wall thickness of the connection between the bottom plate and the output part in the radial direction is t4, wherein t1, t2, t3 and t4 satisfy: t4>t1=t2>t3.

9. The cup-type flexible wheel according to claim 8, characterized in that: A first straight line is defined, the distance between the first straight line and the end of the gear ring away from the bottom plate is L1, the first straight line intersects with the extension line of the outer contour of the cylinder at a first point, the point where the outer contour of the bottom plate and the output portion meet is a second point, the point where the perpendicular bisector of the line between the first point and the second point intersects with the bottom plate is a third point, and the wall thickness at the third point is t3.

10. A harmonic reducer, characterized in that: include: Annular rigid internal gear teeth; The cup-type flexspline according to any one of claims 1 to 9, wherein the flexspline is partially meshed with the inner gear teeth; as well as A wave generator is clamped in the flexible wheel.

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