Cycloid reducer and assembling method thereof

Abstract

The present disclosure provides a cycloid reducer including an input shaft, a cycloid gear disc, a roller wheel set, a plurality of connection shafts, a first output plate and a second output plate. The cycloid gear disc includes a center shaft hole and a shaft holes. The center shaft hole runs through the cycloid gear disc in an axial direction and is used for the input shaft to pass through. The roller wheel set is sleeved on the cycloid gear disc. The plurality of connection shafts pass the cycloid gear disc through the shaft holes, are parallel to the axial direction, and are selected from a combination of a long straight shaft and a short straight shaft. The first output plate and the second output plate are respectively arranged on two opposite sides of the cycloid gear disc. The plurality of connection shafts are fixed to the first output plate, the short straight shaft is connected to the second output plate, and the long straight shaft is engaged with the second output plate, so that the first output plate and the second output plate are kept coaxial. When the input shaft drives the cycloid gear disc to mesh with the roller wheel set, the connection shafts drive the first output plate and the second output plate to rotate.

Description

[Technical Field]

[0001] This case relates to a speed reducer structure, particularly a cycloidal speed reducer and its assembly method, wherein the front and rear output discs are assembled by a long straight shaft and a short straight shaft to optimize processing, improve assembly accuracy, and reduce costs. [Previous Technology]

[0002] Currently, the reducers commonly used in robotic arms on the market can be roughly divided into two structural types: "cycloidal reducer" and "harmonic reducer". Both types of reducers are designed to be lightweight, compact, and have high-speed characteristics.

[0003] Harmonic reducers are mainly composed of a wave generator, flexible gears, and rigid gears. The harmonic drive system of a harmonic reducer utilizes the elastic micro-deformation of the flexible gears to perform a pushing operation, thereby transmitting motion and power. Because harmonic reducers use flexible gear transmission, their rigidity is relatively poor. Therefore, harmonic reducers are not impact-resistant and suffer from gear differential friction, resulting in a shorter service life.

[0004] A cycloidal reducer includes an eccentric shaft and two cycloidal disks, each with at least one tooth and linked to the power input shaft and power output shaft, respectively. Its operating principle is that the input shaft drives one of the cycloidal disks to rotate via the eccentric shaft, which in turn causes the other cycloidal disk to drive the output shaft to rotate. The rotation of the two cycloidal disks is actually achieved using corresponding tooth structures. Although traditional cycloidal reducers have advantages such as large transmission ratio, compact structure, and high transmission efficiency, they are larger in size compared to harmonic reducers, which is not conducive to miniaturization.

[0005] In view of this, it is necessary to provide a cycloidal reducer and its assembly method, in which the front and rear output discs are assembled by a long straight shaft and a short straight shaft, so as to optimize the processing, improve the assembly accuracy, reduce the cost, and solve the deficiencies of the prior art. [Summary of the Invention]

[0006] The purpose of this case is to provide a cycloidal reducer and its assembly method, wherein the front and rear output discs are assembled by a long straight shaft and a short straight shaft to optimize processing, improve assembly accuracy, and reduce costs.

[0007] Another objective of this invention is to provide a thin and lightweight cycloidal reducer that, compared to traditional cycloidal reducers, offers advantages in size and weight while maintaining the same specifications. It also maintains the same thickness when used with harmonic reducers, thus replacing existing harmonic reducers and achieving better rigidity. The multiple connecting shafts between the front and rear output discs can replace the traditional cylindrical or eccentric shaft geometry of the output discs with long and short straight shafts. Since the long and short straight shafts have lower machining costs and better control precision, they help reduce the manufacturing cost of the cycloidal reducer, thereby providing a high-torque, high-rigidity, low-cost, and highly replaceable product. The connecting shafts and output discs are detachably connected, optimizing overall machining, reducing the need to remove excessive material from the output discs, and simplifying the machining process. The combination of the short straight shaft and the output disc allows for more precise control of the axial distance of the short straight shaft protruding from the output disc, improving assembly accuracy. Compared to the conventional integrated structure of the geometric protrusion and output disc, the combined structure of the short straight shaft and output disc in this design reduces material usage while maintaining the original geometric requirements. Furthermore, it reduces machining difficulty, thereby lowering manufacturing costs. In other words, the combined structure of the short straight shaft and output disc not only retains the functionality of the conventional integrated structure of the geometric protrusion and output disc but also effectively improves production efficiency and reduces costs. In addition, the long straight shaft design running through the front and rear output discs ensures the coaxiality of the front and rear output discs and guides assembly. Multiple long straight shafts effectively guide the front and rear output discs to maintain coaxiality during assembly, allowing internal parts and double-row ball bearings to be accurately installed in the correct positions, improving assembly accuracy. On the other hand, since the locking end of the short straight shaft is only secured to the output disc with screws, its torque resistance is relatively weak. In contrast, the engaging end of the long straight shaft is designed with an inner hole into which an interference fixing insert can be pressed, causing the outer diameter of the engaging end to expand. After expansion, the engaging end of the long straight shaft and the fixing hole of the output disc can achieve an interference effect, thereby improving overall rigidity and torsional strength. Because the manufacturing cost of the traditional cycloidal reducer's integrated output disc structure and eccentric shaft structure is relatively high, this design replaces the connection mechanism between the front and rear output discs with a combination of long and short straight shafts. The machining cost of both long and short straight shafts is lower, and precision control is better, significantly reducing the manufacturing cost of the cycloidal reducer. This results in a product with high torque, high rigidity, low cost, and high replaceability.

[0008] To achieve the aforementioned objective, this invention provides a cycloidal reducer comprising an input shaft, a cycloidal gear disk, a roller wheel assembly, a plurality of connecting shafts, a first output disk, and a second output disk. The input shaft is arranged axially. The cycloidal gear disk includes a central shaft hole, an external tooth portion, and a plurality of shaft holes, wherein the central shaft hole extends axially through the cycloidal gear disk and is configured for the input shaft to pass through; the external tooth portion is disposed on the outer annular surface of the cycloidal gear disk; and the plurality of shaft holes are equidistantly arranged around the central shaft hole and the external tooth portion. The roller wheel assembly is sleeved on the cycloidal gear disk and includes a plurality of rollers spatially relative to the external tooth portion of the cycloidal gear disk. The plurality of connecting shafts pass through the plurality of shaft holes through the cycloidal gear disk and are parallel to the axial direction, wherein the plurality of connecting shafts are selected from a combination of long straight shafts and short straight shafts. The first output disk and the second output disk are respectively disposed on opposite sides of the cycloidal gear disk and connected to the cycloidal gear disk through a plurality of connecting shafts. Each of the plurality of connecting shafts is fixed to the first output disk. Each short straight shaft forms a locking end and each long straight shaft forms a engaging end. The locking end is connected to the second output disk, and the engaging end passes through the second output disk and engages with the second output disk, so that the first output disk and the second output disk remain coaxial. When the input shaft drives the outer teeth of the cycloidal gear disk to mesh with the plurality of rollers of the roller wheel assembly, the cycloidal gear disk, through the rotation of the plurality of connecting shafts, causes the plurality of connecting shafts to drive the first output disk and the second output disk to rotate.

[0009] In one embodiment, a plurality of connecting shafts pass through and are fixed to the first output disk from the outside to the inside, and extend from the inside of the first output disk to the second output disk to form a locking end or a fastening end.

[0010] In one embodiment, the locking end abuts against the inner side of the second output disk.

[0011] In one embodiment, the locking end includes a threaded hole and a screw, and the second output disk includes a threaded through hole spatially opposite the threaded hole and the screw, and parallel to the axial direction, wherein the screw is locked to the threaded hole through the threaded through hole, so that the locking end abuts against the inner side of the second output disk and is fixed to each other.

[0012] In one embodiment, the engaging end passes through the inside of the second output disk.

[0013] In one embodiment, the engaging end further includes an inner hole and a fixing plug, wherein the second output disk includes a fixing hole that is spatially opposite to the inner hole and the fixing plug and is parallel to the axial direction, wherein the engaging end passes through the fixing hole of the second output disk, and the fixing plug is inserted into the inner hole in a direction parallel to the axial direction, so that the engaging end and the fixing hole interfere with each other and are fixed.

[0014] In one embodiment, after the fixing plug is inserted into the inner hole of the engaging end, the outer diameter of the engaging end expands and interferes with and fixes with the second output disk.

[0015] In one embodiment, the central shaft hole of the cycloidal gear disk is sleeved on an eccentric part of the input shaft through a needle roller bearing.

[0016] In one embodiment, the cycloidal reducer further includes a spacer ring disposed between the eccentric portion of the input shaft and the deep groove bearing.

[0017] To achieve the aforementioned objective, this invention further provides an assembly method for a cycloidal reducer, comprising the steps of: (a) providing a first output disc and a plurality of connecting shafts, the plurality of connecting shafts being fixed to the first output disc and parallel to the axial direction, wherein the plurality of connecting shafts are selected from a combination of long straight shafts and short straight shafts, each short straight shaft forming a locking end and each long straight shaft forming a engaging end; (b) providing an input shaft and a cycloidal gear disc, wherein the input shaft is axially disposed on the first output disc, the cycloidal gear disc includes a central shaft hole, an external tooth portion, and a plurality of shaft holes, wherein the central shaft hole extends axially through the cycloidal gear disc and allows the input shaft to pass through, the external tooth portion is disposed on the outer annular surface of the cycloidal gear disc, and the plurality of shaft holes are equidistantly arranged around the central shaft hole and the external tooth portion, allowing the plurality of connecting shafts to pass through and being parallel to the axial direction; (c) providing a roller wheel assembly, sleeved on the cycloidal gear disc, and including a plurality of rollers spatially relative to the external tooth portion of the cycloidal gear disc; (d) A second output disk is provided, disposed on the opposite side of the cycloidal gear disk away from the first output disk, and connected to the first output disk via a plurality of connecting shafts, wherein a locking end is connected to the second output disk and a engaging end passes through the second output disk; (e) the locking end is fixed by locking it to the second output disk with screws; and (f) the engaging end is fixed by inserting a fixing plug into the inner hole of the engaging end to create a tight fit interference with the second output disk.

[0018] In one embodiment, in step (a), a plurality of connecting shafts pass through and are fixed to the first output disk from the outside to the inside, and extend from the inside of the first output disk to the second output disk to form a locking end or a fastening end.

[0019] In one embodiment, the locking end includes a threaded hole and a screw, and the second output disk includes a threaded through hole spatially opposite to the threaded hole and the screw, and parallel to the axial direction, wherein in step (e), the screw is locked to the threaded hole through the threaded through hole, so that the locking end abuts against the inner side of the second output disk and is fixed to each other.

[0020] In one embodiment, the second output disk includes a fixing hole that is spatially opposite to the inner hole and the fixing plug and is parallel to the axial direction. In step (f), the engaging end passes through the fixing hole of the second output disk, and the fixing plug is inserted into the inner hole in a direction parallel to the axial direction, so that the engaging end interferes with the fixing hole and is fixed.

[0021] In one embodiment, the plurality of shaft holes of the cycloidal gear disk are respectively sleeved on the corresponding short straight shaft or long straight shaft among the plurality of connecting shafts through bushings.

Implementation Method

[0022] Some typical embodiments embodying the features and advantages of this invention will be described in detail in the following description. It should be understood that this invention can have various variations in different forms, all of which do not depart from the scope of this invention, and the descriptions and drawings therein are essentially for illustrative purposes and not for limiting this invention. For example, if the following description of this disclosure refers to a first feature disposed on or above a second feature, it indicates that it includes embodiments in which the first feature and the second feature are in direct contact, and also includes embodiments in which additional features may be disposed between the first feature and the second feature, so that the first feature and the second feature may not be in direct contact. In addition, different embodiments in this disclosure may use repeated reference numerals and / or markings. These repetitions are for simplification and clarity and are not intended to limit the various embodiments and / or the relationship between the appearance structures. Furthermore, to facilitate the description of the relationship between one component or feature and another (plural) component or feature in the drawings, spatial terms such as "front," "rear," "inner," "outer," and similar terms may be used. In addition to the orientations illustrated in the diagrams, spatially related terms are used to cover different orientations of the device in use or operation. The device may also be otherwise positioned (e.g., rotated 90 degrees or located in other orientations), and the descriptions of the spatially related terms used will be interpreted accordingly. Furthermore, when a component is referred to as "connected to" or "coupled to" another component, it may be directly connected to or coupled to the other component, or there may be intervening components. Although the numerical ranges and parameters of the broad scope of this disclosure are approximate, the values ​​are stated as precisely as possible in specific examples. Additionally, it is understood that while terms such as "first," "second," etc., may be used in the claims to describe different components, these components should not be limited by these terms, and the components described accordingly in the embodiments are represented by different component symbols. These terms are used to distinguish different components. For example, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component without departing from the scope of the embodiments. The term "and / or" as thus used includes any or all combinations of one or more of the related listed items.

[0023] Figure 1 is a perspective view showing the structure of the cycloidal reducer according to the first embodiment of this invention. Figure 2 is a cross-sectional view showing the cycloidal reducer according to the first embodiment of this invention. Figure 3 is a front view of Figure 2. Refer to Figures 1 to 3. This invention provides a thin and light cycloidal reducer 1 with a front and rear output design. In this embodiment, the cycloidal reducer 1 includes an input shaft 10, a cycloidal gear disk 20, a roller wheel assembly 30, a plurality of connecting shafts, a first output disk 60, and a second output disk 70. The input shaft 10 is arranged along the axial direction C. The cycloidal gear disk 20 includes a central shaft hole 21, an external tooth portion 22, and a plurality of shaft holes 23. In this embodiment, the central shaft hole 21 penetrates the cycloidal gear disk 20 along the axial direction C and is configured to allow the input shaft 10 to pass through. The external tooth portion 22 is disposed on the outer annular surface of the cycloidal gear disk 20. A plurality of shaft holes 23 are disposed equidistantly around the central shaft hole 21 and the external tooth portion 22. The roller wheel assembly 30 is sleeved on the cycloidal gear disk 20 and includes a plurality of rollers 31 spatially relative to the external tooth portion 22 of the cycloidal gear disk 20. It should be noted that the plurality of connecting shafts are selected from combinations of long straight shafts 50 and short straight shafts 40. In this embodiment, the cycloidal gear disk 20 includes eight shaft holes 23 equidistantly disposed around the central shaft hole 21 and the external tooth portion 22. The plurality of connecting shafts are composed of four short straight shafts 40 and four long straight shafts 50, corresponding to the eight shaft holes 23. A plurality of connecting shafts, with short straight shafts 40 and long straight shafts 50 arranged alternately, pass through a plurality of shaft holes 23 to the cycloidal gear disk 20, and are parallel to the axial direction C. In this embodiment, the first output disk 60 and the second output disk 70 are respectively disposed on opposite sides of the cycloidal gear disk 20, and are connected to the cycloidal gear disk 20 by a plurality of connecting shafts, serving as the front output disk (first output disk 60) and the rear output disk (second output disk 70). In this embodiment, each of the plurality of connecting shafts is fixed to the first output disk 60. Each short straight shaft 40 is fixed to the first output disk 60 by a fixing end 41, and a locking end 42 is formed by a protrusion on the inner side of the first output disk 60 parallel to the axial direction C. In addition, each long straight shaft 50 is fixed to the first output disk 60 by a fixing end 51, and a locking end 52 is formed by a protrusion on the inner side of the first output disk 60 parallel to the axial direction C. In this embodiment, the locking end 42 connects to the inner side of the second output disk 70, and the engaging end 52 passes through the second output disk 70 and engages with it. The first output disk 60 and the second output disk 70 are connected by a plurality of connecting shafts composed of short straight shafts 40 and long straight shafts 50, which allows the first output disk 60 and the second output disk 70 to remain coaxial. In this embodiment, when the input shaft 10 drives the outer tooth 22 of the cycloidal gear disk 20 to mesh with a plurality of rollers 31 of the roller wheel assembly 30, the cycloidal gear disk 20, through the rotation of the short straight shafts 40 and long straight shafts 50 of the plurality of connecting shafts, causes the short straight shafts 40 and long straight shafts 50 of the plurality of connecting shafts to drive the first output disk 60 and the second output disk 70 to rotate.Of course, the number and arrangement of the shaft hole 23, the short straight shaft 40 and the long straight shaft 50 can be adjusted according to the actual application requirements, and this case is not limited to this.

[0024] In this embodiment, a plurality of short straight shafts 40 of the connecting shafts are fixed to the first output disk 60 by passing through the fixing hole 61 of the first output disk 60 from the outside to the inside through the fixing end 41, and extend from the inside of the first output disk 60 toward the second output disk 70 to form a locking end 42. Additionally, a plurality of long straight shafts 50 of the connecting shafts are fixed to the first output disk 60 by passing through the fixing hole 62 of the first output disk 60 from the outside to the inside through the fixing end 51, and extend from the inside of the first output disk 60 toward the second output disk 70 to form a engaging end 52. It should be noted that the method of fixing the short straight shafts 40 to the first output disk 60 to form the locking end 42 and the long straight shafts 50 to the first output disk 60 to form the engaging end 52 is not a limitation of the essential technology of this invention. However, compared to the conventional integrated structure of geometric protrusions and output disks, the combined structure of the short straight shaft 40 and the first output disk 60 in this case reduces material usage while maintaining the original geometric requirements and is easier to assemble and fix. In this embodiment, when the first output disk 60 and the second output disk 70 are connected by a plurality of connecting shafts, the locking end 42 of the short straight shaft 40 will abut against the inner side of the second output disk 70, and the engaging end 52 of the long straight shaft 50 will further penetrate through the second output disk 70 and engage with the second output disk 70.

[0025] In this embodiment, the locking end 42 of each short straight shaft 40 includes a threaded hole 43 and a screw 44, the threaded hole 43 and the second screw 44 being, for example, a screw hole and a bolt that mate with each other. Additionally, the second output disk 70 includes four threaded through holes 71. The threaded through holes 71 are spatially opposite to the threaded holes 43 and the screw 44, and parallel to the axial direction C. When the short straight shaft 40 is connected between the first output disk 60 and the second output disk 70, the screw 44 is locked to the threaded hole 43 through the threaded through holes 71, allowing the locking end 42 of the short straight shaft 40 to abut against the inner side of the second output disk 70 and be fixed to each other.

[0026] In this embodiment, the engaging end 52 of each long straight shaft 50 passes through the inner side of the second output disk 70. Each engaging end 52 of the long straight shaft 50 further includes an inner hole 53 and a fixing insert 54. Additionally, the second output disk 70 includes four fixing holes 72, the inner diameter of each fixing hole 72 being slightly larger than the outer diameter of each long straight shaft 50. The fixing holes 72 are spatially opposite the inner hole 53 and the fixing insert 54, and are parallel to the axial direction C. When the long straight shaft 50 is connected between the first output disk 60 and the second output disk 70, the engaging end 52 of the long straight shaft 50 will pass through the fixing holes 72 of the second output disk 70. At this time, the fixing insert 54, inserted into the inner hole 53 along the direction parallel to the axial direction C, creates an interference effect, causing the outer diameter of the engaging end 52 of the long straight shaft 50 to expand. After expansion, the engaging end 52 of the long straight shaft 50 and the fixing hole 72 of the second output disk 70 can achieve an interference effect, thereby improving the overall rigidity and torsional strength.

[0027] In this embodiment, the first output disc 60 is sleeved on the input shaft 10 via a deep groove bearing 80, and the second output disc 70 is sleeved on the input shaft 10 via a deep groove bearing 81. In this embodiment, the central shaft hole 21 of the cycloidal gear disc 20 is sleeved on the eccentric portion 11 of the input shaft 10 via a needle roller bearing 83. In this embodiment, the cycloidal reducer 1 further includes a spacer ring 90, which is disposed between the eccentric portion 11 of the input shaft 10 and the deep groove bearings 80 and 81. In addition, in this embodiment, the first output disc 60 is connected to the roller wheel assembly 30 via a ball bearing 84, and the second output disc 70 is connected to the roller wheel assembly 30 via a ball bearing 85. In this embodiment, the plurality of shaft holes 23 of the cycloidal gear disc 20 are respectively sleeved on the corresponding short straight shaft 40 or long straight shaft 50 among the plurality of connecting shafts via bushings 82.

[0028] It is worth noting that, in this embodiment, the first output disc 60 and the second output disc 70 are located on opposite outer sides of the cycloidal gear disc 20 and the roller conveyor assembly 30, respectively, so that both the first output disc 60 and the second output disc 70 can be used for power output. The connection between the two output discs is achieved by using a combination of a long straight shaft 50 and a short straight shaft 40 instead of the traditional cylindrical structure or eccentric shaft geometry of the output disc. When corresponding to a traditional cycloidal reducer, this combination offers the advantages of smaller size and lighter weight while maintaining the same specifications. When corresponding to a harmonic reducer, the thickness can be the same, thus replacing the original harmonic reducer and achieving better rigidity. Since the short straight shaft 40 and the long straight shaft 50 have lower processing costs and better control precision, they help reduce the manufacturing cost of the cycloidal reducer 1, thereby providing a product with high torque, high rigidity, low cost, and high replaceability. The short straight shaft 40 and the long straight shaft 50 are detachably connected to the first output disc 60 and the second output disc 70, which optimizes the overall processing, eliminates the need to remove too much material, and simplifies the processing procedure.

[0029] Regarding the aforementioned cycloidal reducer 1, this invention further proposes an assembly method for the cycloidal reducer. Figure 4 is a flowchart illustrating the assembly method of the cycloidal reducer according to the first embodiment of this invention. Figures 5A to 5E illustrate the assembly process of the cycloidal reducer according to the first embodiment of this invention. Referring to Figures 1 to 5E. First, in step S1, a first output disk 60 and a plurality of connecting shafts are provided. The plurality of connecting shafts are fixed to the first output disk 60 and parallel to the axial direction C, wherein the plurality of connecting shafts are composed of four long straight shafts 50 and four short straight shafts 40. After each of the plurality of connecting shafts is fixed to the first output disk 60, as shown in Figure 5A, each short straight shaft 40 protrudes from the inner side of the first output disk 60 parallel to the axial direction C to form a locking end 42. In addition, each long straight shaft 50 protrudes from the inner side of the first output disk 60 parallel to the axial direction C to form a locking end 52. Of course, the splicing method of the short straight shaft 40, the long straight shaft 50, and the first output disk 60 can be adjusted according to actual application requirements, and this case is not limited to this. Next, in step S2, an input shaft 10 and a cycloidal gear disk 20 are provided for assembly with the aforementioned structure. The input shaft 10 is disposed on the first output disk 60 along the axial direction C. The central shaft hole 21 of the cycloidal gear disk 20 passes through the cycloidal gear disk 20 along the axial direction C and allows the input shaft 10 to pass through. The outer tooth portion 22 is disposed on the outer ring surface of the cycloidal gear disk 20. A plurality of shaft holes 23 are equidistantly arranged around the central shaft hole 21 and the outer tooth portion 22, and allow a plurality of short straight shafts 40 and long straight shafts 50 to pass through correspondingly and parallel to the axial direction C. In step S3, a roller wheel assembly 30 is provided and fitted onto the outer periphery of the cycloidal gear disk 20, with the plurality of rollers 31 of the roller wheel assembly 30 corresponding to the outer teeth 22 of the cycloidal gear disk 20, as shown in Figure 5B. Then, in step S4, a second output disk 70 is provided, disposed on the side of the cycloidal gear disk 20 and the roller wheel assembly 30 away from the first output disk 60, and connected to the first output disk 60 via a plurality of connecting shafts, as shown in Figure 5C. At this time, the locking end 42 of the short straight shaft 40 contacts the inner side of the second output disk 70, and the engaging end 52 of the long straight shaft 50 passes through the fixing hole 72 of the second output disk 70, while the second output disk 70 remains in a detachable state. In step S5, as shown in Figure 5D, screw 44 is used to lock the second output disk 70 through the threaded through hole 71 and threaded hole 43, so that the locking end 42 of the short straight shaft 40 abuts against the inner side of the second output disk 70, and is fixed to each other by the locking action of screw 44 and the second output disk 70. Since the short straight shaft 40 and the first output disk 60 are pre-assembled, the axial distance of the short straight shaft 40 protruding from the first output disk 60 can be controlled more precisely, thereby improving the assembly accuracy with the second output disk 70. Compared with the conventional integrated structure of geometric protrusion and output disk, the combined structure of the short straight shaft 40 and the first output disk 60 in this case reduces the amount of material used while maintaining the original geometric requirements. In addition, it reduces the processing difficulty, thereby reducing manufacturing costs.In other words, the combined structure of the short straight shaft 40 and the first output disk 60 not only retains the functionality of the conventional integrated structure of geometric protrusions and output disks, but also effectively improves production efficiency and reduces costs. Furthermore, it should be noted that the assembly structure completed in step S5 allows for specification verification to confirm whether the first output disk 60 and the second output disk 70 are coaxial. If the first output disk 60 and the second output disk 70 are not coaxial, adjustments to the parts are still allowed until specification verification is passed. Finally, in step S6, as shown in Figure 5E, after the coaxial state of the first output disk 60 and the second output disk 70 has passed specification verification, the fixing plug 54 is inserted into the inner hole 53 of the engaging end 52 of the long straight shaft 50 along the direction of parallel axis C, causing the outer diameter of the engaging end 52 of the long straight shaft 50 to expand. After expansion, the engaging end 52 of the long straight shaft 50 and the fixing hole 72 of the second output disk 70 can achieve an interference effect and be fixed. Because the locking end 42 of the short straight shaft 40 is only locked to the second output disc 70 through the screw 44, its torque resistance is relatively weak. In contrast, the long straight shaft 50, which runs through the first output disc 60 and the second output disc 70, can better ensure the coaxiality of the front and rear output discs and guide the assembly. In other words, multiple long straight shafts 50 can effectively guide the first output disc 60 and the second output disc 70 to remain coaxial in the aforementioned assembly process, so that the cycloidal gear disc 20, the roller wheel set 30, and the double-row ball bearings 84 and 85 can be accurately installed in the correct position, improving assembly accuracy. On the other hand, the design of the engaging end 52 of the long straight shaft 50, with the fixing insert 54 pressed into the inner hole 53, causes the engaging end 52 to interfere with the fixing hole 72 of the second output disc 70 for fixation, which further helps to improve the overall rigidity and torsional strength.

[0030] It is worth noting that, in this embodiment, the number, arrangement, and pre-assembly method of the short straight shafts 40 and long straight shafts 50 with the first output disk 60 can be adjusted according to actual application requirements. In the embodiment shown in Figure 5A, four short straight shafts 40 are fixed to the first output disk 60 by passing through the fixing holes 61 of the first output disk 60 from the outside to the inside through the fixing ends 41 (see Figure 3), and extend from the inside of the first output disk 60 toward the second output disk 70 to form locking ends 42. In addition, four long straight shafts 50 are fixed to the first output disk 60 by passing through the fixing holes 62 of the first output disk 60 from the outside to the inside through the fixing ends 51, and extend from the inside of the first output disk 60 toward the second output disk 70 to form engaging ends 52. In other embodiments, the short straight shafts 40 and long straight shafts 50 can be used alternately, and are not limited to the same number.

[0031] Figure 6 illustrates the combination of a plurality of connecting shafts connecting the first output disc in the cycloidal reducer of the second embodiment of this invention. In this embodiment, the structure of the first output disc 60 and the connecting shaft is generally similar to that shown in Figures 1 to 3 and Figure 5A, and the same component reference numerals represent the same components, structures, and functions, which will not be repeated here. In this embodiment, the four long straight shafts 50 in Figure 5A are replaced, for example, by four long eccentric shafts 50a. The engaging end 52 of the long eccentric shaft 50a also includes an inner hole 53. When assembled with the second output disc 70, the inner hole 53 is allowed to be inserted into the fixing plug 54 along the direction of the parallel axis C to produce an interference effect, causing the outer diameter of the engaging end 52 of the long eccentric shaft 50a to expand and interfere with the fixing hole 72 of the second output disc 70 for fixation, thereby improving the overall rigidity and torsional strength. Of course, this invention is not limited to this.

[0032] Figure 7 illustrates the combination of a plurality of connecting shafts connecting the first output disk in the cycloidal reducer of the third embodiment of this invention. In this embodiment, the structure of the first output disk 60 and the connecting shaft is generally similar to that shown in Figures 1 to 3 and Figure 5A, and the same component numbers represent the same components, structures and functions, which will not be repeated here. In this embodiment, the four long straight shafts 50 in Figure 5A are replaced, for example, by four short straight shafts 40. After the eight short straight shafts 40 are combined with the first output disk 60, the axial distance of the short straight shafts 40 protruding from the first output disk 60 can be precisely controlled, improving the assembly accuracy with the second output disk 70. Furthermore, the locking end 42 of the short straight shaft 40 can be locked to the inside of the second output disk 70 by means of screws 44, threaded through holes 71 and threaded holes 43. Compared to the conventional integrated structure of geometric protrusions and output disks, the combination of the short straight shaft 40 and the first output disk 60 in this case more effectively improves production efficiency and reduces costs. Of course, this case is not limited to this.

[0033] Figure 8 illustrates the combination of a plurality of connecting shafts connecting the first output disc in the cycloidal reducer of the fourth embodiment of this invention. In this embodiment, the structure of the first output disc 60 and the connecting shaft is generally similar to that shown in Figures 1 to 3 and Figure 5A, and the same component numbers represent the same components, structures, and functions, which will not be repeated here. In this embodiment, the four short straight shafts 40 in Figure 5A are replaced, for example, by four long straight shafts 50. The eight long straight shafts 50 can effectively guide the first output disc 60 and the second output disc 70 to remain coaxial during the assembly process, so that the internal parts can be accurately installed in the correct position, improving the assembly accuracy. Furthermore, the long straight shafts 50 are fixed by pressing the fixing plug 54 into the inner hole 53, so that the engaging end 52 interferes with the fixing hole 72 of the second output disc 70, which further helps to improve the overall rigidity and torsional strength. Of course, this invention is not limited to this.

[0034] As can be seen from the above, for the plurality of connecting shafts between the first output disc 60 and the second output disc 70 in the cycloidal reducer 1, the combination can be selected from any combination of short straight shaft 40, long straight shaft 50, and long eccentric shaft 50a. The number of individual connecting shafts, the overall number, and the arrangement can also be adjusted according to actual application requirements. The short straight shaft 40 precisely controls the axial distance between the output discs, and the long straight shaft 50 and long eccentric shaft 50a guide the coaxiality of the front and rear output discs, thereby improving the overall rigidity and torsional strength, without interfering with each other. Of course, the application of the connecting shaft combination output disc in this case is not limited to this, and will not be elaborated further.

[0035] In summary, this invention provides a cycloidal reducer and its assembly method. The front and rear output discs are assembled using long and short straight shafts to optimize processing, improve assembly accuracy, and reduce costs. This thin and light cycloidal reducer offers the advantage of smaller size and lighter weight compared to traditional cycloidal reducers, while maintaining the same specifications. It can also maintain the same thickness when used with harmonic reducers, replacing the original harmonic reducer and achieving better rigidity. The multiple connecting shafts between the front and rear output discs can replace the traditional cylindrical structure or eccentric shaft geometry of the output discs using long and short straight shafts. Since the long and short straight shafts have lower processing costs and better precision control, they help reduce the manufacturing cost of the cycloidal reducer, thus providing a high-torque, high-rigidity, low-cost, and highly replaceable product. The connecting shafts and output discs are detachably connected, optimizing overall processing, reducing the need to remove excessive material from the output discs, and simplifying the processing procedure. The combination of the short straight shaft and the output disc allows for more precise control of the axial distance of the short straight shaft protruding from the output disc, thus improving assembly accuracy. Compared to the conventional integrated structure of the geometric protrusion and output disc, the combined structure of the short straight shaft and output disc in this design reduces material usage while maintaining the original geometric requirements. Furthermore, it reduces machining difficulty, thereby lowering manufacturing costs. In other words, the combined structure of the short straight shaft and output disc not only retains the functionality of the conventional integrated structure of the geometric protrusion and output disc but also effectively improves production efficiency and reduces costs. In addition, the design of the long straight shaft running through the front and rear output discs ensures the coaxiality of the front and rear output discs and guides assembly. Multiple long straight shafts effectively guide the front and rear output discs to remain coaxial during the assembly stage, allowing internal parts and double-row ball bearings to be accurately installed in the correct positions, improving assembly accuracy. On the other hand, since the locking end of the short straight shaft is only secured to the output disc with screws, its torque resistance is relatively weak. In contrast, the engaging end of the long straight shaft is designed with an inner hole into which an interference fixing insert can be pressed, causing the outer diameter of the engaging end to expand. After expansion, the engaging end of the long straight shaft and the fixing hole of the output disc can achieve an interference effect, thereby improving overall rigidity and torsional strength. Because the manufacturing cost of the traditional cycloidal reducer's integrated output disc structure and eccentric shaft structure is relatively high, this design replaces the connection mechanism between the front and rear output discs with a combination of long and short straight shafts. The machining cost of both long and short straight shafts is lower, and precision control is better, significantly reducing the manufacturing cost of the cycloidal reducer. This results in a product with high torque, high rigidity, low cost, and high replaceability.

[0036] This case can be modified in various ways by a person skilled in this technology, but all of them are subject to the protection sought by the scope of the attached patent application. [Simplified Explanation of the Diagram]

[0037] Figure 1 is a perspective view of the structure of the cycloidal reducer of the first embodiment of this case.

[0038] Figure 2 is a cross-sectional structural diagram of the cycloidal reducer of the first embodiment of this case.

[0039] Figure 3 is the front view of Figure 2.

[0040] Figure 4 is a flowchart illustrating the assembly method of the cycloidal reducer according to the first embodiment of this case.

[0041] Figures 5A to 5E illustrate the assembly process of the cycloidal reducer of the first embodiment of this case.

[0042] Figure 6 shows the combination of a plurality of connecting shafts connecting the first output disc in the cycloidal reducer of the second embodiment of this case.

[0043] Figure 7 shows the combination of a plurality of connecting shafts connecting the first output disc in the cycloidal reducer of the third embodiment of this case.

[0044] Figure 8 shows the combination of a plurality of connecting shafts connecting the first output disc in the cycloidal reducer of the fourth embodiment of this case.

Claims

1. A cycloidal reducer, comprising: One input shaft, set along one axis; A cycloidal gear disk includes a central shaft hole, an external tooth portion, and a plurality of shaft holes, wherein the central shaft hole extends through the cycloidal gear disk along the axial direction and is configured to allow the input shaft to pass through; the external tooth portion is disposed on the outer annular surface of the cycloidal gear disk; and the plurality of shaft holes are equidistantly arranged around the central shaft hole and the external tooth portion; a roller wheel assembly is sleeved on the cycloidal gear disk and includes a plurality of rollers spatially relative to the external tooth portion of the cycloidal gear disk. A plurality of connecting shafts pass through the plurality of shaft holes of the cycloidal gear disk and are parallel to the axial direction, wherein the plurality of connecting shafts are selected from a combination of a long straight shaft and a short straight shaft; and a first output disk and a second output disk are respectively disposed on two opposite sides of the cycloidal gear disk and connected to the cycloidal gear disk through the plurality of connecting shafts, wherein each of the plurality of connecting shafts is fixed to the first output disk, each of the short straight shafts forms a locking end, each of the long straight shafts forms a engaging end, the locking end is connected to the second output disk, and the engaging end passes through the second output disk and engages with the second output disk, so that the first output disk and the second output disk remain coaxial, wherein when the input shaft drives the external tooth portion of the cycloidal gear disk to mesh with the plurality of rollers of the roller wheel assembly, the cycloidal gear disk, by rotating with the plurality of connecting shafts, causes the plurality of connecting shafts to drive the first output disk and the second output disk to rotate.

2. The cycloidal reducer as claimed in claim 1, wherein the plurality of connecting shafts pass through and are fixed to the first output disk from the outside to the inside, and extend from the inside of the first output disk to the second output disk to form the engaging end or the locking end.

3. The cycloidal reducer as claimed in claim 2, wherein the locking end abuts against the inside of the second output disc.

4. The cycloidal reducer as claimed in claim 3, wherein the locking end includes a threaded hole and a screw, the second output disc includes a threaded through hole spatially opposite the threaded hole and the screw and parallel to the axial direction, wherein the screw is locked to the threaded hole through the threaded through hole, such that the locking end abuts against the inner side of the second output disc and is fixed to each other.

5. The cycloidal reducer as claimed in claim 2, wherein the engaging end passes through the inside of the second output disc.

6. The cycloidal reducer as claimed in claim 5, wherein the engaging end further includes an inner hole and a fixing plug, wherein the second output disc includes a fixing hole spatially opposite the inner hole and the fixing plug and parallel to the axial direction, wherein the engaging end passes through the fixing hole of the second output disc, and the fixing plug is inserted into the inner hole in a direction parallel to the axial direction, so that the engaging end interferes with the fixing hole and is fixed.

7. The cycloidal reducer as claimed in claim 6, wherein after the fixing plug is inserted into the inner hole of the engaging end, the outer diameter of the engaging end expands and interferes with and fixes against the second output disc.

8. The cycloidal reducer as claimed in claim 1, wherein the central shaft hole of the cycloidal gear is fitted onto an eccentric portion of the input shaft via a needle roller bearing.

9. The cycloidal reducer as claimed in claim 8 further includes a spacer ring disposed between the eccentric portion of the input shaft and a deep groove bearing.

10. A method for assembling a cycloidal reducer, comprising the steps of: (a) providing a first output disc and a plurality of connecting shafts, the plurality of connecting shafts being fixed to the first output disc and parallel to an axial direction, wherein the plurality of connecting shafts are selected from a combination of a long straight shaft and a short straight shaft, each of the short straight shafts forming a locking end and each of the long straight shafts forming a engaging end; (b) providing an input shaft and a cycloidal gear disk, wherein the input shaft is disposed on the first output disc along the axial direction, the cycloidal gear disk including a central shaft hole, an external tooth portion and a plurality of shaft holes, wherein the central shaft hole penetrates the cycloidal gear disk along the axial direction and allows the input shaft to pass through, the external tooth portion is disposed on the outer annular surface of the cycloidal gear disk, and the plurality of shaft holes are equidistantly disposed around the central shaft hole and the external tooth portion, allowing the plurality of connecting shafts to pass through and being parallel to the axial direction; (c) (d) A roller assembly is provided, fitted onto the cycloidal gear disk, and includes a plurality of rollers spatially relative to the outer teeth of the cycloidal gear disk; (e) A second output disk is provided, disposed on the other side of the cycloidal gear disk away from the first output disk, and connected to the first output disk via the plurality of connecting shafts, wherein the locking end is connected to the second output disk, and the engaging end passes through the second output disk; (f) The locking end is fixed by locking it to the second output disk with a screw; and (c) The engaging end is fixed by inserting a fixing plug into an inner hole of the engaging end to create a tight fit interference with the second output disk.

11. The assembly method of the cycloidal reducer as claimed in claim 10, wherein in step (a), the plurality of connecting shafts are fixed to the first output disk through the outer side of the first output disk and extend from the inner side of the first output disk to the second output disk to form the engaging end or the locking end.

12. The assembly method of the cycloidal reducer as claimed in claim 10, wherein the locking end includes a threaded hole and the screw, the second output disc includes a threaded through hole spatially opposite the threaded hole and the screw and parallel to the axial direction, wherein in step (d), the screw is locked to the threaded hole through the threaded through hole, so that the locking end abuts against the inner side of the second output disc and is fixed to each other.

13. The assembly method of the cycloidal reducer as claimed in claim 10, wherein the second output disc includes a fixing hole spatially opposite the inner hole and the fixing plug and parallel to the axial direction, wherein in step (f), the engaging end passes through the fixing hole of the second output disc, and the fixing plug is inserted into the inner hole in a direction parallel to the axial direction, so that the engaging end interferes with the fixing hole and is fixed.

14. The assembly method of the cycloidal reducer as described in claim 10, wherein the plurality of shaft holes of the cycloidal gear disk are respectively fitted onto the corresponding short straight shaft or the long straight shaft among the plurality of connecting shafts through a bushing.

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