Long-arc multi-tooth full-meshing cycloidal speed reducer
By designing a long-arc multi-tooth full-meshing cycloidal reducer, the problems of low torque transmission, short fatigue life, and high machining accuracy of harmonic reducers are solved, achieving the effects of increased torque, extended life, reduced cost, and improved accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-12
- Publication Date
- 2026-04-03
AI Technical Summary
Existing harmonic reducers suffer from problems such as low transmitted torque, short fatigue life, high machining accuracy, and high cost. In particular, under high reduction ratio conditions, flexible gears are prone to fatigue damage and are difficult to machine.
The long-arc multi-tooth full-meshing cycloidal reducer adopts a design that reduces the gear tooth difference to 1 through the full meshing of the flexible cycloidal gear and the internal gear. The deformation position of the flexible cycloidal gear is moved to the elastic disk, reducing the amount of deformation, increasing the torque transmission capacity and fatigue resistance, and simplifying the processing requirements.
Increasing torque transmission capacity within the same size range extends product life, reduces machining accuracy and material requirements, lowers costs, and simultaneously improves working accuracy.
Smart Images
Figure CN121782332A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to cycloidal reducers, such as cycloidal reducers that can be widely used in various robots, turntables, etc. Background Technology
[0002] In existing technologies, the main types of speed reducers used to drive robot movements include planetary reducers, RV reducers, and harmonic reducers. Planetary reducers achieve coaxial speed reduction through the meshing of a sun gear, planetary gears, and a ring gear. While achieving high precision and zero backlash is costly, multi-stage reduction results in large axial dimensions. RV reducers use a combination of planetary gears and cycloidal pinwheels for two-stage speed reduction; their structure is complex, with many components, high cost, and significant size and weight. Harmonic reducers utilize the elastic deformation of flexible gears for meshing transmission, resulting in relatively low torsional rigidity. The flexible gears also have limited fatigue life and are not impact-resistant. Additionally, spherical gear reducers, magnetic gear reducers, and integrated joint modules are still in the conceptual exploration stage.
[0003] During operation, the flexible gear in a harmonic reducer is repeatedly stretched and deformed into an elliptical shape. The teeth on the gear rings at both ends of the elliptical long shaft mesh with the internal gear, making the flexible gear prone to fatigue damage. After deformation, the number of teeth on the elliptical long shaft end of the flexible gear participating in meshing is small, resulting in a smaller transmitted torque. Furthermore, for example, when the reduction ratio is 100, since only the teeth at both ends of the elliptical long shaft of the flexible gear mesh, the difference in the number of teeth between the flexible gear and the meshing internal gear is 2. That is, when the number of teeth of the internal gear is 200, the number of teeth of the flexible gear is 198. This means that for a given reducer volume, the number of teeth must be made smaller due to the large number of teeth, resulting in unsatisfactory rigidity. Moreover, harmonic reducers have very high requirements for machining precision and component materials, resulting in high manufacturing costs and an astonishingly high selling price. Summary of the Invention
[0004] The technical problem to be solved by this invention is to address the shortcomings of existing harmonic reducers by proposing a long-arc multi-tooth full-meshing cycloidal reducer. This reducer can overcome the tension stress of the flexible gear ring, reduce the number of gear teeth under the same reduction ratio, thereby extending the product's fatigue life, increasing the transmitted torque, reducing the required machining accuracy, and achieving high working accuracy and reduced product cost.
[0005] The technical solution of the present invention is that the long arc multi-tooth full meshing cycloidal reducer includes a housing with an input shaft. Its technical feature is that a flexible bearing is installed on the input shaft, and a deformation generating structure is provided between the inner ring of the flexible bearing and the input shaft. The flexible cycloidal gear is installed on the flexible bearing. The flexible cycloidal gear meshes with the internal gear (6) and can run as a planetary gear relative to the internal gear (6). The deformation generating structure forces the flexible cycloidal gear (5) to produce elastic deformation so that multiple teeth on a section of arc length α of the flexible cycloidal gear (5) are fully meshed with the internal gear (6). α ≧ 20° angle.
[0006] The present invention will be further described below with reference to the accompanying drawings.
[0007] See Figure 1 and Figure 2 The cycloidal reducer of the present invention includes a housing (11) with an input shaft (1). Its technical feature is that a flexible bearing (7) is mounted on the input shaft (1). A deformation generating structure is provided between the inner ring of the flexible bearing (7) and the input shaft (1). A flexible cycloidal gear (5) is mounted on the flexible bearing (7). The flexible cycloidal gear (5) meshes with a rigid internal gear (6) and can run as a planetary gear relative to the internal gear (6). The deformation generating structure forces the flexible cycloidal gear (5) to undergo elastic deformation so that multiple teeth on a section of arc length α of the flexible cycloidal gear (5) are fully meshed with the internal gear (6). α ≧ 20° angle.
[0008] α refers to the angle of the central angle corresponding to a segment of arc length. According to design requirements, it can be taken in the range of 20° to 240°, preferably 40° to 120°. The internal gear (6) is a power output element, and an output disk (10) can be connected to one side of it to serve as the power output end after speed change.
[0009] The deformation structure described in this invention can be an eccentric bushing (8) installed on the shaft segment of the input shaft (1); or the shaft segment can be machined to be an eccentric shaft relative to the input shaft (1) (equivalent to making the eccentric bushing and the input shaft segment into one piece); in this case, the flexible bearing (7) is preferably a flexible needle bearing, or it can be a flexible ball bearing.
[0010] The deformation structure described in this invention can also be a cam structure formed by installing a bushing with a protrusion on the shaft segment of the input shaft (1), wherein the arc length of the protrusion corresponds to the central angle α; or the shaft segment of the input shaft (1) can be made into an integrated cam structure, wherein the arc length of the protrusion corresponds to the central angle α. In this case, the flexible bearing (7) is preferably a flexible pin bearing, but it can also be a flexible ball bearing.
[0011] The deformation-generating structure described in this invention can also be, for example: Figure 4As shown, the shaft segment of the input shaft (1) is made into an oblique shaft segment (12) relative to the input shaft (1), that is, the axis of the oblique shaft segment (12) forms an angle β with the axis of the input shaft (1), β≧0.1°. According to the design requirements, it can be taken in the range of 0.1° to 2°, preferably 0.1°—1°; the flexible bearing (7) is installed on the oblique shaft segment.
[0012] The deformation generating structure described in this invention can also be various suitable structural elements that can play the same role when installed on the input shaft (1), such as a bushing with a specific wall thickness.
[0013] In this invention, experiments have shown that the flexible cycloidal gear (5) undergoes radial deformation under stress during elastic deformation, engagement, and disengagement, and also experiences other strains due to traction. To overcome the adverse effects of this situation, the flexible cycloidal gear (5) can be constructed in a structure as described in [reference needed]. Figures 5-7 An external tooth is provided at one end of the connecting body (14) to form a gear; further, an elastic disk (15) is provided at the other end of the connecting body (14), the elastic disk being an external folded disk (plate) at one end of the connecting body; the connection part between the elastic disk (15) and the connecting body (14) is provided with a groove (16) surrounding the outer periphery of the connecting body or a convex groove opposite to the downward direction of the groove (16), or other suitable deformation buffer (acceptance) structure; the elastic disk (15) is confined (locked) in the cavity of the housing (11). The connection part between the elastic disk (15) and the groove or convex groove is the elastic deformation zone (151), the elastic deformation zone (151) being the connection part between the inner periphery of the elastic disk (15) and the groove (16), the main deformation of the flexible cycloidal gear (5) during operation occurs in this section; further, a connecting hole (17) can also be provided on the outer periphery of the elastic disk (15), and the elastic disk can be fixedly connected to the housing (11) with fasteners.
[0014] The technical principle of this invention is as follows, see [link / reference] Figure 1 and Figure 2The external power drives the input shaft (1) to rotate. The deformation structure on the shaft causes the flexible bearing (7) and the flexible cycloidal gear (5) to deform accordingly. As a result, multiple teeth of the arc length corresponding to the central angle α on the flexible cycloidal gear are fully meshed with the internal gear (6), that is, multi-tooth backlash-free meshing (other teeth are in a non-meshing or disengaged transitional state). Compared with the structure and working method of the flexible gear of the existing harmonic reducer (machine) being stretched into an ellipse and meshing at both ends of the long shaft, the flexible cycloidal gear of the present invention overcomes this repeated tensioning force and improves the fatigue resistance. Under the same size flexible gear and speed ratio, the present invention has a tooth number difference of 1 between the two meshing gears, for example, their tooth numbers are 100 and 99 respectively, which reduces the number of teeth by half compared with the existing harmonic reducer. Therefore, the teeth can be made relatively large, increasing the load bearing capacity and transmitting greater torque. The multi-tooth full meshing of the present invention effectively ensures the speed transmission accuracy. Figure 5 The structure of the groove (16) of the flexible cycloidal gear (5) shown can effectively improve the component's resistance to strain and fatigue damage, and increase its service life. The groove (16) is proportional to the swing amplitude of the connecting body (14). The greater the swing amplitude, the closer the bottom of the groove is to the axis of the connecting body (14).
[0015] Compared with the prior art, the beneficial effects of the present invention are: 1) This invention relates to a long-arc multi-tooth full-meshing cycloidal reducer. Compared with the harmonic reducer mentioned in the background art, this application, due to the cycloidal effect, changes the deformation position of the flexible cycloidal gear, shifting the deformation position to the elastic disc. Furthermore, the deformation amount is reduced by 1 / 2 to 1 / 8 compared to the flexible gear in the prior art, significantly reducing the deformation of the flexible gear. Therefore, it can overcome the tension stress on the flexible gear ring, reduce the number of gear teeth under the same reduction ratio, extend the product's fatigue life, increase the transmitted torque, reduce the required machining accuracy, and relatively reduce the high-precision requirements of the material. It also offers high working accuracy and lower product cost.
[0016] 2) The present invention is a long arc multi-tooth full meshing cycloidal reducer. Compared with the RV reducer mentioned in the background art, the present application reduces the number of internal working parts, has a simple structure, greatly reduces the processing difficulty, and increases the working accuracy. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of one embodiment of the present invention; Figure 2 yes Figure 1 The diagram shows the radial section of this part when the internal gear and the flexible cycloidal gear are meshing. Figure 3 yes Figure 1A schematic diagram of an eccentric bushing structure as one embodiment of the deformation-generating structure; Figure 4 yes Figure 1 A schematic diagram of the oblique axis segment structure, which serves as another embodiment of the deformation-generating structure; Figure 5 yes Figure 1 A schematic diagram of the first embodiment of the flexible cycloidal gear; Figure 6 yes Figure 1 A schematic diagram of the second embodiment of the flexible cycloidal gear; Figure 7 yes Figure 1 A schematic diagram of the third embodiment of the flexible cycloidal gear; Figure 8 yes Figure 1 A schematic diagram (front view) of an embodiment of an internal gear; Figure 9 yes Figure 6 A schematic diagram of the radial cross-section of the internal gear shown. Figure 10 This is a schematic diagram of another embodiment of the present invention.
[0018] In the figure 1—Input shaft; 2—End cover; 3—Bearing A; 4—Bearing B; 5—Flexible cycloidal gear; 6—Internal gear; 7—Flexible bearing; 8—Eccentric bushing; 9—Bearing C; 10—Output disc; 11—Housing; 12—Helical shaft section; 13—Gear teeth; 14—Connecting body; 15—Elastic disc; 151—Elastic deformation zone; 16—Groove; 17—Connecting hole; 18—Pressure cover; 19—Taply tapered roller bearing; 20—Taply tapered roller bearing; 21—Flange; 22—Internal gear ring; 23—Bearing cavity; 24—Connecting ring; 25—Snap ring. Detailed Implementation
[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" used below only indicate that they correspond to the upper, lower, left, and right directions in the accompanying drawings and do not limit the structure.
[0020] Example 1, see Figure 1 and Figure 2The cycloidal reducer of the present invention includes a housing (11) with an input shaft (1), a flexible bearing (7) is mounted on the input shaft (1), a deformation generating structure is provided between the inner ring of the flexible bearing (7) and the input shaft (1), a flexible cycloidal gear (5) is mounted on the flexible bearing (7), and the flexible cycloidal gear (5) meshes with a rigid internal gear (6) and can perform planetary gear operation relative to the internal gear (6). Figure 3 As shown, the deformation-generating structure is an eccentric bushing (8) fixedly fitted onto the input shaft (1), and the wall thickness of the eccentric bushing (8) is... Figure 3 The central angle α is 60°. The distance oa from any point on the outer circumference of the eccentric bushing corresponding to this central angle α to the center of the circle is equal (oa1=oa2). This arc-shaped bushing allows multiple teeth of the corresponding tooth segment of the flexible cycloidal gear to achieve full meshing with the internal gear; while Figure 3 In the middle arc segment b1b2b3, the distance ob from any point on the outer periphery of the eccentric bushing to the center of the circle is equal (ob1=ob2=ob3), and the length oa>ob. The running part of the bushing in this arc segment is the state where the flexible cycloidal gear and the internal gear are disengaged. In contrast, the running parts of the bushings in the arc segments a1b1 and a2b3 are the transitional states between the flexible cycloidal gear and the internal gear, from engagement to disengagement or from disengagement to engagement.
[0021] like Figures 1-9 As shown, a cover (2) is installed on one side of the housing (11), and a bearing A (3) is installed between the cover (2) and the input shaft (1); the internal gear (6) on the other side of the housing (11) has a bearing cavity (23) located on one side of the internal gear ring (22) and equipped with a bearing C (9), and the internal gear (6) is connected to the input shaft (1) via the bearing C (9); a connecting ring (24) is also installed in the housing (11), and the connecting ring (24) is connected to the housing (11) via the bearing B (4), and the output disk (10) located at the outer end of the other side of the housing (11) is fixedly connected to the internal gear (6) and the connecting ring (24) in sequence via connecting elements (fasteners); flexible cycloidal gear The connecting body (14) of the wheel (5) is located in the annular cavity between the connecting ring (24) and the input shaft (1). The elastic disc (15) is placed in the annular gap between the end cover (2) and the connecting ring (24). The connection part between the elastic disc (15) and the groove or protrusion is the elastic deformation zone (151). The elastic deformation zone (151) is the connection part between the inner circumference of the elastic disc (15) and the groove (16). The main deformation of the flexible cycloidal gear (5) during operation occurs in this section. The outer circumference of the elastic disc (15) abuts against the retaining ring (25) installed between the housing (11) and the end cover (2). The outer bottom of the groove (16) abuts against the inclined step on the inner side of the end cover (2). The elastic disc is an outer folded disc (plate) at one end of the connecting body.
[0022] The flexible cycloidal gear (5) has a root circle diameter of 43.45 mm, a gear module of 0.5, and a connecting body (14) wall thickness of 1.6 mm. The flexible cycloidal gear (5) has 79 teeth, the internal gear (6) has 80 teeth, and the diameter of the root circle of the internal gear (6) is 44 mm. The difference in the number of teeth is 1.
[0023] Suitable for reducers used in robot joints.
[0024] Example 2, see Figure 10 and Figure 2 The cycloidal reducer of the present invention includes a housing (11) with an input shaft (1), a flexible bearing (7) is mounted on the input shaft (1), a deformation generating structure is provided between the inner ring of the flexible bearing (7) and the input shaft (1), a flexible cycloidal gear (5) is mounted on the flexible bearing (7), and the flexible cycloidal gear (5) meshes with a rigid internal gear (6) and can run as a planetary gear relative to the internal gear (6). The deformation structure is the same as in Example 1, with a central angle α of 45°. A cover (2) is installed on one side of the housing (11), and a bearing A (3) is installed between the cover (2) and the input shaft (1). The internal gear (6) in the housing (11) is connected to the input shaft (1) via bearing C (9). A pair of tapered roller bearings (19, 20) are installed between the internal gear (6) and the housing (11). The pressure cap (18) on the other side of the housing (11) is fixedly connected to the housing (11) via connecting elements (fasteners). The connecting body (14) of the flexible cycloidal gear (5) is located in the annular cavity between the internal gear (6) and the input shaft (1), and the elastic disc (15) is placed in the annular gap between the end cover (2) and the internal gear (6). The outer periphery of the elastic disc (15) is provided with a connecting hole (17) (see [link]). Figure 5 The elastic disc (15) is fixedly connected to the end cap through the connection hole (17) and fasteners.
[0025] The flexible cycloidal gear (5) has a root circle diameter of 125.73 mm, a gear module of 1.27, and a connecting body (14) with a wall thickness of 3 mm. The flexible cycloidal gear (5) has 99 teeth, the internal gear (6) has a tooth root circle diameter of 127 mm, the internal gear (6) has 100 teeth, and the tooth number difference is 1.
[0026] Suitable for rotary table reducers.
[0027] Example 3, a cycloidal reducer as in Example 1, adopts a deformation generating structure different from that in Example 1; the deformation generating structure is that the shaft segment of the input shaft (1) is made into an oblique shaft segment (12) relative to the input shaft (1), that is, the axis of the oblique shaft segment (12) forms an angle β with the axis of the input shaft (1), and the angle of β can be 0.1°, 0.2°, 0.5° or 1°.
[0028] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.
Claims
1. A long-arc multi-tooth full-meshing cycloidal reducer, comprising a housing (11) housing an input shaft (1), characterized in that, The input shaft (1) is equipped with a flexible bearing (7). A deformation generating structure is provided between the inner ring of the flexible bearing (7) and the input shaft (1). A flexible cycloidal gear (5) is installed on the flexible bearing (7). The flexible cycloidal gear (5) meshes with the internal gear (6) and can run as a planetary gear relative to the internal gear (6). The deformation generating structure forces the flexible cycloidal gear (5) to undergo elastic deformation, so that multiple teeth on a segment of arc length α of the flexible cycloidal gear (5) are fully meshed with the internal gear (6). α refers to the angle of the central angle corresponding to a segment of arc length, α≧20°. The gear (6) is a power output element.
2. The long-arc multi-tooth full-meshing cycloidal reducer according to claim 1, characterized in that, The value of α ranges from 20° to 240°.
3. The long-arc multi-tooth fully meshing cycloidal reducer according to claim 2, characterized in that, The value of α ranges from 40° to 120°.
4. The long-arc multi-tooth full-meshing cycloidal reducer according to claim 1, characterized in that, The deformation-generating structure is an eccentric bushing (8) installed on the input shaft (1) shaft segment.
5. The long-arc multi-tooth fully meshing cycloidal reducer according to claim 1, characterized in that, The deformation-generating structure is a cam structure formed by installing a bushing with a protrusion on the shaft segment of the input shaft (1).
6. The long-arc multi-tooth fully meshing cycloidal reducer according to claim 1, characterized in that, The deformation structure is that the shaft segment of the input shaft (1) is made into an oblique shaft segment (12) relative to the input shaft (1), that is, the axis of the oblique shaft segment (12) forms an angle β with the axis of the input shaft (1), and β≧0.1°.
7. The long-arc multi-tooth fully meshing cycloidal reducer according to claim 6, characterized in that, The value of β ranges from 0.1° to 2°.
8. The long-arc multi-tooth fully meshing cycloidal reducer according to claim 1, characterized in that, The flexible cycloidal gear (5) has an external tooth set at one end of the connecting body (14) to form a gear.
9. The long-arc multi-tooth full-meshing cycloidal reducer according to claim 8, characterized in that, An elastic disc (15) is provided at the other end of the connector (14). The connection part between the elastic disc (15) and the connector (14) is provided with a groove (16) surrounding the outer periphery of the connector or a convex groove in the opposite direction to the groove (16). The elastic disc (15) is fixed in the cavity of the housing (11).
10. The long-arc multi-tooth fully meshing cycloidal reducer according to claim 8, characterized in that, An elastic disc (15) is provided at the other end of the connector (14). The connection part between the elastic disc (15) and the connector (14) is provided with a groove (16) surrounding the outer periphery of the connector or a protrusion in the opposite direction to the groove (16). A connection hole (17) is provided on the outer periphery of the elastic disc (15), and the elastic disc is fixedly connected to the housing (11) with fasteners.