Industrial robot joint reduction device

Abstract

This invention discloses a joint reduction device for industrial robots, belonging to the technical field of industrial robot reducers. The reduction device includes an input shaft, planetary gears, a crankshaft, a cycloidal gear, a pinion housing, an input planetary carrier, and an output planetary carrier. Both the input and output planetary carriers have an integrally designed raceway serving as the inner raceway of an angular contact ball bearing. The input shaft meshes with three planetary gears. When the input shaft rotates, the input gears drive the planetary gears and the crankshaft to rotate. The crankshaft rotates synchronously and drives the two cycloidal gears to oscillate. The rotation vector of the cycloidal gears is transmitted to the output planetary carrier, achieving the purpose of speed reduction and torque increase. Under load, the resultant force of the meshing force on the cycloidal gear is always located in the area between the tooth root and the through hole of the cycloidal gear, reducing tooth deformation in this area. This invention uses marking arc grooves and positioning holes on the reduction device to avoid errors caused by visual alignment, improving the joint position accuracy.

Description

Technical Field

[0001] This invention belongs to the field of industrial robot reducer technology, and particularly relates to an industrial robot joint deceleration device. Background Technology

[0002] Currently, industrial robots are developing towards lightweight design, which requires that the rated output torque of the joint reduction device of industrial robots be increased as much as possible while maintaining the existing external dimensions; or the weight of the reduction device be reduced as much as possible while ensuring the rated output torque.

[0003] RV reducers are among the most widely used precision reducers in the field of industrial robots, such as... Figure 5 The diagram shown is a load-bearing schematic of a cycloidal gear in an unoptimized existing RV reducer. The cycloidal gear in the RV reducer has a through hole. Figure 5 (Irregularly shaped holes) and crankshaft mounting holes ( Figure 5 The medium-sized circular bore (crankshaft mounting hole) is used to mount the crankshaft and needle roller cage assembly. When the crankshaft is the input end, its rotation drives the cycloidal gear to oscillate. The through hole allows the rigid pins on the output flange or planetary carrier to pass through, converting the oscillating motion of the cycloidal gear into the rotational output of the output flange or planetary carrier. Additionally, the through hole provides a lubrication and cooling channel inside the reduction gear. However, from... Figure 5 It can be seen that the wall thickness of the cycloidal gear tooth root and the through hole in the vertical direction is ( Figure 5 (Illustrated by A) is thinner than other areas, resulting in poor bending stiffness and a low natural vibration frequency. Under load, the resultant force on the cycloidal gear teeth intersects at the vertical point ( Figure 5 (Illustrated by B) It will fall into the through hole. Elastic deformation will occur in the vicinity of this place and on the tooth surface, which will result in a shortened tooth surface life.

[0004] Furthermore, to improve production cycle time, industrial robot joints often employ low-ratio reduction gears. In this case, the input gear uses a spline structure to connect to the input shaft. Because the thickness between the input gear tooth root and the internal spline tooth root is thin, it affects strength. To allow space for a spiral bevel gear, the input shaft must also have increased external spline length and locking thread length, which places precision requirements on the axial installation position of the input shaft.

[0005] Finally, when calibrating the zero point of each joint of an industrial robot, most robots use marking on the robot body. This method is suitable for applications with moderate precision requirements and high maintenance frequency, but it is not suitable for applications with higher precision requirements. Summary of the Invention

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] The present invention first provides an industrial robot joint reduction device, including an input shaft, planetary gears, a crankshaft, a cycloidal gear, a pin gear housing, an input planetary carrier, and an output planetary carrier;

[0008] Both the input and output planetary carriers have an integrally designed raceway serving as the inner raceway of the angular contact ball bearing. The needle gear housing is connected to the input and output planetary carriers with raceways via the outer ring assembly of the angular contact ball bearing. The input shaft is located in the center hole of the input and output planetary carriers and meshes with three planetary gears through the input gear. The planetary gears are coaxially connected to the crankshafts located in the crankshaft mounting holes of the input and output planetary carriers. Two cycloidal gears, the first and second, with a phase difference of 180°, are hinged to the eccentric shaft sections of the three crankshafts. The two cycloidal gears mesh with needle rollers placed in the needle gear grooves. The input and output planetary carriers are fixedly connected as one unit, and the output planetary carrier is connected to the through holes of the two cycloidal gears, converting the oscillating motion of the cycloidal gears into the rotational output of the output planetary carrier.

[0009] The tooth profile parameters of the first cycloidal gear and the second cycloidal gear are configured such that, under load, the resultant force of the meshing force on the cycloidal gear always lies within the region between the tooth root and the through hole of the cycloidal gear.

[0010] As a preferred embodiment of the present invention, the input planetary carrier with raceways and the output planetary carrier with raceways are positioned by internally threaded tapered pins and are connected and fixed together by internal hexagonal head screws.

[0011] As a preferred embodiment of the present invention, the input shaft is hinged to the center holes of the input planetary carrier and the output planetary carrier respectively by two second tapered roller bearings. There is a bushing between the inner rings of the two second tapered roller bearings in the axial direction. The outer rings of the two second tapered roller bearings are pre-tightened by elastic retaining rings through the second hole. There is a washer at the front end of the input shaft. The washer is pressed against the inner ring of the second tapered roller bearing away from the teeth of the input gear by an internal hexagon socket head cap screw connected to the input shaft. There is a gap between the washer and the end face of the input shaft.

[0012] As a preferred embodiment of the present invention, the outer contour of the needle-tooth shell is a quadrilateral structure, the four sides of the quadrilateral are of the same length, and adjacent sides are connected by a rounded transition.

[0013] As a preferred embodiment of the present invention, the needle roller radius satisfies the following relationship:

[0014] ;

[0015] in, The radius of the distribution circle of the needle-tooth shell is given. The number of rollers, The radius of the needle roller;

[0016] Under the rated torque, obtain the maximum contact stress between the needle roller radius and the tooth surface for different values ​​that satisfy the above formula. The relationship between the two was considered, and finally, the maximum contact stress on the tooth surface was selected. The minimum needle radius value is taken as the radius of the needle.

[0017] As a preferred embodiment of the present invention, the tooth profile forming parameters of the first cycloidal gear and the second cycloidal gear satisfy the following relationship:

[0018] ;

[0019] Where e is the eccentricity of the cycloidal gear;

[0020] Under rated torque, obtain the eccentricity and maximum tooth surface load of the cycloidal gear that satisfy the above formula. The relationship between the two gears is considered. Finally, the eccentricity corresponding to the minimum maximum load on the tooth surface is selected as the eccentricity of the first cycloidal gear and the second cycloidal gear.

[0021] As a preferred embodiment of the present invention, when the cycloidal gear tooth profile generated after determining the roller radius and eccentricity interferes with the tooth tip of the needle tooth shell, on the basis of retaining the inflection point of the cycloidal gear, a portion of the depth of the tooth tip of the cycloidal gear or the tooth tip of the needle tooth shell is further removed, or a portion of the depth of both the tooth tip of the cycloidal gear and the tooth tip of the needle tooth shell is removed, to ensure that the cycloidal gear and the needle tooth shell do not interfere with each other during movement.

[0022] As a preferred embodiment of the present invention, the input gear on the input shaft is integrally fixed with the input shaft, there is an external spline next to the input gear, the external spline is located on the same side as the input planetary carrier, and there are threaded holes at the corresponding center parts at both ends of the input shaft.

[0023] A shoulder is provided on the input shaft near the teeth to restrict the axial movement of the second tapered roller bearing near the teeth. There is an adjusting shim between the inner ring of the second tapered roller bearing near the teeth and the shoulder.

[0024] As a preferred embodiment of the present invention, the diameter of the sealing ring on the outer circle of the output planetary carrier is larger than the diameter of the positioning surface on the outer circle of the output planetary carrier, and the sealing ring is made of fluororubber; the end face of the output planetary carrier has a positioning inner hole.

[0025] As a preferred embodiment of the present invention, the needle tooth shell has a first marking arc groove in the vertical direction, the output planetary carrier end face has a positioning hole in the horizontal direction, and a second marking arc groove is located at an angle of 87° with the positioning hole.

[0026] This invention features a reasonable and compact structure. The reduction gear increases output torque while maintaining a lightweight design. Both the output and input planetary carriers utilize a bearing raceway structure, with the inner ring raceway of the angular contact ball bearing integrally integrated with the planetary carrier, reducing assembly time and errors, and facilitating assembly.

[0027] This invention, while maintaining the external dimensions of the deceleration device, adjusts component parameters so that the resultant force of the cycloidal gear teeth intersects at point B in the vertical direction between the tooth root and the through hole A. This reduces tooth deformation in this area, increases the natural vibration frequency, and extends tooth life. If the cycloidal gear tooth tip exceeds the tip circle of the pinion tooth shell, the corresponding interference amount is removed from the cycloidal gear tooth tip or the pinion tooth shell tooth tip, or a certain depth is removed from both the cycloidal gear tooth tip and the pinion tooth shell tooth tip, while retaining the cycloidal gear inflection point. This avoids interference between the cycloidal gear tooth tip and the pinion tooth shell, while leaving lubrication space to achieve heat dissipation.

[0028] The diameter of the sealing ring on the outer circle of the output planetary carrier of this invention is larger than the diameter of the outer circle of the output planetary carrier assembly positioning surface, which avoids the sealing ring scratching the sealing lip when it is installed in the reduction gear, thus preventing oil leakage. The sealing ring is made of fluororubber, which is suitable for the high-temperature environment inside the reduction gear. The needle tooth housing adopts a quadrilateral and transition arc structure, which reduces the weight of the reduction gear.

[0029] In this invention, there is a bushing between the inner rings of the two second tapered roller bearings in the central hole of the planetary carrier. The outer rings of the two second tapered roller bearings are pre-tightened by elastic retaining rings through holes on both sides. The internal hexagonal head screw is connected to the input shaft through a shim against the inner ring of the second tapered roller bearing. There is a gap between the shim and the end face of the input shaft. There is an adjusting shim between the inner ring of the second tapered roller bearing near the teeth on the input shaft and the shaft shoulder. It can be used to adjust the axial position of the input shaft and the mounting end face of the pin tooth housing. By selecting the adjusting shim, the axial installation accuracy of the input shaft and the mounting end face of the pin tooth housing can be improved.

[0030] The input shaft of this invention has an internal threaded hole at the center of the external spline area near the input planetary carrier end, which is used for the installation and locking of the spiral bevel gear. This changes the previous method of locking with external threads and nuts, and shortens the length of the input shaft.

[0031] The two threaded holes on the end face of the input planetary carrier of the present invention are used to install positioning blocks with zero-position marks. The pin tooth housing and the output planetary carrier have marking arc grooves for the zero-position marks of the joint deceleration device of the industrial robot. The marking arc grooves on the deceleration device are detected by the electronic controller, which directly correlates with the actual position of the joint, avoiding errors caused by visual alignment and improving the joint position accuracy. Attached Figure Description

[0032] Figure 1 This is a front view of the industrial robot joint deceleration device of the present invention;

[0033] Figure 2 yes Figure 1 BB cross-sectional view;

[0034] Figure 3 yes Figure 2 The view to the view;

[0035] Figure 4 This is the present invention. Figure 3 A magnified view of a portion of the image;

[0036] Figure 5 This is a schematic diagram of a cycloidal gear under load, without the optimization of this invention.

[0037] Figure 6 This is a schematic diagram of the optimized load-bearing system according to the present invention;

[0038] Figure 7 This is a schematic diagram of the optimized cycloidal gear tooth profile and load according to the present invention;

[0039] Figure 8 It is the transmission efficiency curve of the speed reduction device A(1);

[0040] Figure 9 It is the transmission efficiency curve of the speed reduction device A(2);

[0041] Figure 10 It is the transmission efficiency curve of the speed reduction device A(3);

[0042] Figure 11 It is the transmission efficiency curve of the speed reduction device B(1);

[0043] Figure 12 This is the transmission efficiency curve of the speed reduction device B(2);

[0044] Figure 13 This is the transmission efficiency curve of the speed reduction device B(3).

[0045] In the diagram, 1-output planetary carrier; 2-first sealing cover; 3-first tapered roller bearing; 4-elastic retaining ring for first bore; 5-second sealing cover; 6-washer; 7-needle roller retainer assembly; 8-shield; 9-first hexagon socket head cap screw; 10-elastic retaining ring for second bore; 11-second tapered roller bearing; 12-sealing ring; 13-outer ring assembly of angular contact ball bearing; 14-pin gear housing; 15-needle roller; 16-first cycloidal gear; 17-second cycloidal gear; 18-input planetary carrier; 19-internal threaded tapered pin; 20-shaft sleeve; 21-adjusting shim; 22-input shaft; 23-elastic retaining ring for shaft; 24-planetary gear; 25-crankshaft; 26-second hexagon socket head cap screw. Detailed Implementation

[0046] The present invention will be further described and illustrated below with reference to specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0047] like Figures 1 to 3 As shown, the deceleration device of the present invention is used as a joint deceleration device for an industrial robot. It mainly includes components such as a needle gear housing 14, a needle roller 15, an angular contact ball bearing outer ring assembly 13, an input planetary carrier 18 with raceways, an output planetary carrier 1 with raceways, an input shaft 22 containing an input gear, planetary gears 24, a crankshaft 25, a first cycloidal gear 16, and a second cycloidal gear 17. The input planetary carrier 18 and the output planetary carrier 1 each have three corresponding crankshaft mounting holes, which are evenly distributed in the circumferential direction. Furthermore, the input planetary carrier 18 and the output planetary carrier 1 have a central hole for mounting the input shaft 22.

[0048] In this invention, the input shaft serves as the input end and has an input gear. The input gear meshes with three planetary gears 24, which are coaxially connected to three crankshafts 25. Two cycloidal gears 16 and 17, with a phase difference of 180°, are hinged to the eccentric shaft sections of the three crankshafts 25 via a needle roller retainer assembly 7. The two cycloidal gears mesh with needle rollers 15 placed in needle tooth grooves. The three crankshafts 25 are further evenly distributed in the crankshaft mounting holes of the input planetary carrier 18 and the output planetary carrier 1 via first tapered roller bearings 3. The outer rings of the two first tapered roller bearings 3 are pre-tightened by elastic retaining rings 4 through the first holes on both sides. When the input shaft rotates, the input gear drives the planetary gears 24 to rotate, and the crankshafts 25 rotate synchronously, causing the two cycloidal gears to oscillate. The rigid pins on the output planetary carrier pass through the through holes on the two cycloidal gears. Figure 6 The three irregular holes in the cycloidal gear convert the oscillating motion of the cycloidal gear into the rotational output of the planetary carrier.

[0049] In this embodiment, the input planetary carrier 18 and the output planetary carrier 1 are positioned by internally threaded tapered pins 19 and connected and fixed together by second internal hexagonal head screws 26, as shown. Figure 1 and Figure 2 As shown.

[0050] like Figure 2As shown, the needle tooth housing 14 has a groove inside, which is arranged circumferentially along the inner wall of the needle tooth housing 14. A needle roller 15 is arranged on the groove. One side of the needle tooth housing 14 in the axial direction is connected to the input planetary carrier 18 with raceway through an outer ring assembly 13 of an angular contact ball bearing, and the other side is connected to the output planetary carrier 1 with raceway through another outer ring assembly 13 of an angular contact ball bearing. The raceways of the input planetary carrier 18 and the output planetary carrier 1 serve as the inner ring raceways of the angular contact ball bearings. They are designed and manufactured integrally with the corresponding planetary carriers. This invention integrates the inner ring raceways of the angular contact ball bearings with the planetary carriers, which can reduce assembly time and assembly errors, and facilitate assembly.

[0051] An input shaft 22 containing an input gear meshes with three sets of planetary gears 24, which are located outside the input planetary carrier 18 and evenly distributed circumferentially. The side of the input shaft 22 containing the external spline is placed on the same side of the input planetary carrier 18. The input shaft 22 is hinged to the center holes of the input planetary carrier 18 and the output planetary carrier 1 respectively through two second tapered roller bearings 11 (of the two second tapered roller bearings 11, the second tapered roller bearing 11 closer to the teeth is hinged to the center hole of the input planetary carrier 18, and the second tapered roller bearing 11 farther from the teeth is hinged to the center hole of the output planetary carrier 1). There is a bushing 20 between the inner rings of the two second tapered roller bearings 11 to control the axial distance. The outer rings of the two second tapered roller bearings 11 are connected by two... The second hole on the side is pre-tightened with an elastic retaining ring 10. There is a shim 8 on the front end of the input shaft 22. In this invention, a first internal hexagon socket head cap screw 9 connected to the input shaft 22 is used to press the shim 8 against the inner ring of the second tapered roller bearing 11 away from the teeth. The shim 8 does not directly contact the front end face of the input shaft 22 but there is a gap (that is, the front end face of the second tapered roller bearing 11 away from the teeth is not flush with the front end face of the input shaft 22). A shoulder is provided on the input shaft 22 near the teeth to restrict the axial movement of the second tapered roller bearing 11 near the teeth. There is an adjusting shim 21 between the inner ring of the second tapered roller bearing 11 near the teeth and the shoulder. In this invention, the axial position of the input shaft is adjusted by adjusting the shim 21.

[0052] A sealing ring 12 is installed between the output planetary carrier 1 and the pin tooth housing 14. The three evenly distributed crankshaft mounting holes of the output planetary carrier 1 are fitted with a first sealing cover 2, and the center hole is fitted with a second sealing cover 5.

[0053] Figure 5 The diagram shows the load on the cycloidal gear of an existing speed reduction device. The resultant force of the force on the teeth of the cycloidal gear intersects at point B in the vertical direction, which falls inside the through hole. Elastic deformation occurs near this point and on the tooth surface, resulting in a shortened tooth life. Figure 6 and Figure 7This diagram illustrates the tooth profiles and load conditions of the first cycloidal gear 16 and the second cycloidal gear 17 in the speed reduction device of this invention. By adjusting the parameters of the cycloidal gears, this invention ensures that, after being loaded (transmitting the load), the point of application B of the resultant force of the meshing force on the cycloidal gear falls between the tooth root and the through hole (area A). The point of application of the resultant force refers to the contact force generated between the first cycloidal gear 16 or the second cycloidal gear 17 and the needle roller 15 when they mesh to transmit the load. This contact force acts on the tooth profile of the cycloidal gear along the normal direction of the meshing point. Since multiple needle rollers participate in the meshing simultaneously, the contact forces at each meshing point can be combined into an equivalent resultant force; the point of application of this resultant force is the point of application of the resultant force. Figure 6 As shown in B in the diagram.

[0054] To meet the above design requirements, this invention further optimizes the needle roller radius and the eccentricity of the cycloidal gear. The needle roller radius satisfies the following relationship:

[0055] ;

[0056] in, The radius of the distribution circle of the needle-tooth shell is given. The number of rollers, The radius of the needle roller is given.

[0057] The present invention further obtains the maximum contact stress between various needle roller radii and tooth surfaces that satisfy the above formula under the rated torque by using the tooth surface contact stress calculation process of cycloidal gears. The relationship between the two was considered, and finally, the maximum contact stress on the tooth surface was selected. The minimum needle radius value is taken as the radius of the needle.

[0058] The tooth profile forming parameters of the first cycloidal gear 16 and the second cycloidal gear 17 satisfy the following relationship:

[0059] ;

[0060] Where e is the eccentricity of the cycloidal gear.

[0061] The present invention further obtains the eccentricity and maximum tooth surface load of each cycloidal gear satisfying the above-mentioned conditions under rated torque. The relationship between the two gears is considered. Finally, the eccentricity corresponding to the minimum maximum load on the tooth surface is selected as the eccentricity of the first cycloidal gear 16 and the second cycloidal gear 17.

[0062] If the cycloidal gear tooth profile generated after meeting the above design requirements interferes with the tooth tip of the pinion tooth housing, then, while retaining the inflection point of the cycloidal gear, a portion of the depth of the cycloidal gear tooth tip or the pinion tooth tip can be removed, or a certain depth can be removed from both the cycloidal gear tooth tip and the pinion tooth tip, to ensure that the cycloidal gear and the pinion tooth housing do not interfere with each other during movement. Using the aforementioned cycloidal gear can increase the allowable output torque of the reduction gear while providing lubrication space for heat dissipation.

[0063] In actual use, when the pin gear housing 14 is fixed, if power is input clockwise from the splined input shaft 22, the input gear on the input shaft 22 simultaneously meshes with the three circumferential planetary gears 24. The planetary gears 24 are fixed to the crankshaft 25, driving the crankshaft 25 to move eccentrically. The first cycloidal gear 16 and the second cycloidal gear 17, which are 180° out of phase, are hinged to the three crankshafts 25 through the needle roller retainer assembly 7 and mesh with the needle rollers 15 placed on the output planetary carrier. While the first cycloidal gear 16 and the second cycloidal gear 17 are rotating under the action of the eccentric shaft section of the crankshaft 25, they generate a torque on the needle rollers 15 in the pin gear housing groove in the same direction as the cycloidal gear's revolution, causing the output planetary carrier to rotate clockwise.

[0064] like Figure 1 As shown, the outer contour of the needle-tooth shell 14 is a quadrilateral structure, with all four sides of equal length and adjacent sides connected by a rounded transition. This design of the needle-tooth shell outer contour can reduce the overall weight and avoid interference with the robot body.

[0065] like Figure 1 As shown, in one embodiment of the present invention, the input planet carrier 18 end face passes through the center of one of the planetary gears ( Figure 1 Two threaded holes are located along one diameter of the planetary carrier 1 (located at the bottom planetary gear) for mounting a positioning block with a zero-position mark to output the positioning outer circle of the planetary carrier 1. Figure 2 (C) Output planetary carrier 1 end face ( Figure 2 (middle D) and the positioning hole on the end face ( Figure 3 Based on F), such as Figure 1 As shown, these two threaded holes have positional requirements relative to references C, D, and F. Figure 3 and Figure 4 As shown, the needle-tooth shell 14 has a first marking arc groove in the vertical direction ( Figure 4 The upper marking arc groove), there is a positioning hole in the horizontal direction on the end face of the output planet carrier 1, and there is a second marking arc groove at an 87° angle to the positioning hole ( Figure 4The marked arc groove located at the bottom is used as a zero-position mark for the joint deceleration device of industrial robots. The marked arc groove on the deceleration device is detected by the electronic controller and directly associated with the actual position of the joint, avoiding errors caused by visual alignment and improving the accuracy of joint position.

[0066] The invention features a reasonable and compact structure. The reduction gear increases output torque while maintaining a lightweight design. The output and input planetary carriers adopt a bearing raceway structure, with the inner ring raceway of the angular contact ball bearing integrally integrated with the planetary carrier, reducing assembly time and errors while facilitating assembly. While maintaining the overall dimensions of the reducer, parameters are adjusted so that the resultant force of the cycloidal gear teeth intersects at point B in the vertical direction between the tooth root and through hole A, reducing tooth deformation in this area, increasing the natural vibration frequency, and extending tooth life. If the cycloidal gear tooth tip exceeds the pinion tooth tip circle, the corresponding interference amount is removed from the cycloidal gear tooth tip or pinion tooth tip while retaining the cycloidal gear inflection point, or a certain depth is removed from both the cycloidal gear tooth tip and pinion tooth tip to avoid interference between the cycloidal gear tooth tip and the pinion tooth tip, while also leaving lubrication space for heat dissipation. The diameter of the sealing ring on the outer circle of the output planetary carrier is larger than the diameter of the outer circle mounting positioning surface of the output planetary carrier, preventing the sealing ring from scratching the sealing lip during installation in the reducer and causing oil leakage. The sealing ring is made of fluororubber, suitable for the high-temperature environment inside the reducer. The needle gear housing features a quadrilateral shape and a transition arc structure, reducing the weight of the reduction gear. A bushing exists between the inner rings of the two second tapered roller bearings in the planetary carrier's central hole. The outer rings of the two second tapered roller bearings are pre-tightened with elastic retaining rings through the second holes on both sides. Hexagonal socket head cap screws are connected to the input shaft via shims against the inner rings of the second tapered roller bearings. A gap exists between the shims and the end face of the input shaft. Adjusting shims exist between the inner ring of the second tapered roller bearing near the teeth on the input shaft and the shaft shoulder, which can be used to adjust the axial position of the input shaft and the mounting face of the needle gear housing. By selecting and matching adjusting shims, the axial installation accuracy between the input shaft and the mounting face of the needle gear housing can be improved. An internal threaded hole is provided at the center of the external spline area near the input planetary carrier end of the input shaft for locking the spiral bevel gear, changing the previous method of locking with external threads and nuts, and shortening the length of the input shaft. Marking arc grooves are marked on the reduction gear for zero-position marking of the industrial robot joint reduction gear, avoiding errors caused by visual alignment and improving joint position accuracy.

[0067] The effects of this invention are explained below with reference to experimental data:

[0068] Speed ​​Reduction Device A: Cycloidal Wheel Forming Parameters: Eccentricity =1.3mm, radius of the distribution circle of the needle teeth ring =68.5mm, number of teeth on the pin gear ring =40, number of teeth on the cycloidal gear =39, needle roller radius =3mm. The outer radius of the through hole is 59.5mm. The resultant force of the cycloidal gear in this reduction device acts radially at point B, which falls within the through hole. The distance A between the root of the cycloidal gear and the through hole is 4.7mm.

[0069] Speed ​​Reduction Device B: Cycloidal Wheel Forming Parameters: Eccentricity =1.6mm, needle tooth ring distribution circle radius, needle roller radius =69.5mm, number of teeth on the pin gear ring =40, number of teeth on the cycloidal gear =39, needle roller radius =3mm. The outer radius of the through hole is 59.5mm. The point of application B of the resultant force of the cycloidal gear in this reduction device falls between the root of the cycloidal gear tooth and the through hole (satisfying the requirements of this invention). The distance A between the root of the cycloidal gear tooth and the through hole is 5.4mm. In the reduction device, to avoid interference between the tip of the cycloidal gear tooth and the tip circle of the pin tooth ring, and to leave space for heat dissipation, 0.3mm is removed from the tip of the cycloidal gear tooth with the center of the cycloidal gear as the center.

[0070] Three prototypes of both speed reducer A and speed reducer B were taken and installed on the speed reducer performance test bench. The relevant data are as follows:

[0071] Table 1

[0072] From the data in the table above and Figures 8 to 13 It can be seen that, in terms of temperature rise, reduction gear B is 3.8℃ lower than reduction gear A, transmission efficiency is increased by 5%, and the representative value of torsional stiffness is increased by 12%. Measuring the starting torque of the reduction gears using the performance testing system, reduction gear B is approximately 0.25 Nm lower than reduction gear A. Through comparative experiments, accelerated overload tests were conducted on both reduction gears. After the tests, the wear on the cycloidal gear teeth in reduction gear A was more severe than that in reduction gear B, indicating that the lifespan of the cycloidal gears in reduction gear B is improved to some extent. The above data demonstrate that reduction gear B achieves significant improvements in temperature rise, transmission efficiency, torsional stiffness, starting torque, and lifespan.

[0073] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. An industrial robot joint reduction device, comprising an input shaft, planetary gears, a crankshaft, a cycloidal gear, a pin gear housing, an input planetary carrier, and an output planetary carrier, characterized in that: Both the input and output planetary carriers have an integrally designed raceway serving as the inner raceway of the angular contact ball bearing. The needle gear housing is connected to the input and output planetary carriers with raceways via the outer ring assembly of the angular contact ball bearing. The input shaft is located in the center hole of the input and output planetary carriers and meshes with three planetary gears through the input gear. The planetary gears are coaxially connected to the crankshafts located in the crankshaft mounting holes of the input and output planetary carriers. Two cycloidal gears, the first and second, with a phase difference of 180°, are hinged to the eccentric shaft sections of the three crankshafts. The two cycloidal gears mesh with needle rollers placed in the needle gear grooves. The input and output planetary carriers are fixedly connected as one unit, and the output planetary carrier is connected to the through holes of the two cycloidal gears, converting the oscillating motion of the cycloidal gears into the rotational output of the output planetary carrier. The tooth profile parameters of the first cycloidal gear (16) and the second cycloidal gear (17) are configured such that, under load, the resultant force of the meshing force on the cycloidal gear is always located in the area between the tooth root and the through hole of the cycloidal gear.

2. The industrial robot joint deceleration device according to claim 1, characterized in that, The input planetary carrier (18) with raceways and the output planetary carrier (1) with raceways are positioned by internally threaded tapered pins (19) and are connected and fixed together by second internal hexagonal head screws (26).

3. The industrial robot joint deceleration device according to claim 1, characterized in that, The input shaft (22) is hinged to the center holes of the input planetary carrier (18) and the output planetary carrier (1) respectively through two second tapered roller bearings (11). There is a bushing (20) between the inner rings of the two second tapered roller bearings (11) in the axial direction. The outer rings of the two second tapered roller bearings are pre-tightened by elastic retaining rings (10) through the second hole. There is a washer at the front end of the input shaft. The washer is pressed against the inner ring of the second tapered roller bearing away from the teeth of the input gear by an internal hexagon socket head cap screw connected to the input shaft. There is a gap between the washer and the end face of the input shaft.

4. The industrial robot joint deceleration device according to claim 1, characterized in that, The outer contour of the needle-tooth shell (14) is a quadrilateral structure with four sides of equal length and a circular arc transition between adjacent sides.

5. The industrial robot joint deceleration device according to claim 1, characterized in that, The radius of the needle roller satisfies the following relationship: ； in, The radius of the distribution circle of the needle-tooth shell is given. The number of rollers, The radius of the needle roller; Under the rated torque, obtain the maximum contact stress between the needle roller radius and the tooth surface for different values ​​that satisfy the above formula. The relationship between the two was considered, and finally, the maximum contact stress on the tooth surface was selected. The minimum needle radius value is taken as the radius of the needle.

6. The industrial robot joint deceleration device according to claim 5, characterized in that, The tooth profile forming parameters of the first cycloidal gear (16) and the second cycloidal gear (17) satisfy the following relationship: ； Where e is the eccentricity of the cycloidal gear; Under rated torque, obtain the eccentricity and maximum tooth surface load of the cycloidal gear that satisfy the above formula. Based on the relationship between the two, the eccentricity corresponding to the minimum maximum load on the tooth surface is selected as the eccentricity of the first cycloidal gear (16) and the second cycloidal gear (17).

7. The industrial robot joint deceleration device according to claim 6, characterized in that, When the cycloidal gear tooth profile generated after determining the roller radius and eccentricity interferes with the tooth tip of the needle tooth shell, on the basis of retaining the inflection point of the cycloidal gear, further remove part of the depth of the tooth tip of the cycloidal gear or the tooth tip of the needle tooth shell, or remove part of the depth of both the tooth tip of the cycloidal gear and the tooth tip of the needle tooth shell, to ensure that the cycloidal gear and the needle tooth shell do not interfere with each other during movement.

8. The industrial robot joint deceleration device according to claim 1, characterized in that, The input gear on the input shaft (22) is fixed to the input shaft. There is an external spline next to the input gear. The external spline is located on the same side as the input planetary carrier (18). There are threaded holes at the center of both ends of the input shaft (22). The input shaft (22) has a shoulder near the teeth to restrict the axial movement of the second tapered roller bearing near the teeth. There is an adjusting shim (21) between the inner ring of the second tapered roller bearing near the teeth and the shoulder.

9. The industrial robot joint deceleration device according to claim 1, characterized in that, The diameter of the sealing ring on the outer circle of the output planetary carrier (1) is larger than the diameter of the positioning surface on the outer circle of the output planetary carrier. The sealing ring is made of fluororubber. There is a positioning inner hole on the end face of the output planetary carrier (1).

10. The industrial robot joint deceleration device according to claim 1, characterized in that, The needle housing (14) has a first marking arc groove in the vertical direction, the output planet carrier (1) has a positioning hole in the horizontal direction, and a second marking arc groove is located at an angle of 87° with the positioning hole.

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