Robot high transmission stiffness structure and assembly method

Abstract

This invention belongs to the field of blind mounting technology for the unseen area of ​​RV-C series reducers, and specifically relates to a high transmission rigidity structure and assembly method for robots. It includes a motor, a gear shaft assembly, a casting, a reducer, and a bearing assembly. The casting is connected to the reducer, and an unseen area is left between the casting and the reducer. A bearing assembly is located at the bottom of this unseen area. The gear shaft assembly is connected to the output shaft of the motor, inserted into the unseen area, and is transmitted to the reducer. The end of the gear shaft assembly is supported by the bearing assembly. This invention significantly improves transmission rigidity and accuracy, while reducing transmission vibration and noise, ensuring proper meshing and high transmission efficiency.

Description

Technical Field

[0001] This invention belongs to the field of blind assembly technology for the unseen areas of RV-C series reducers, and specifically relates to a high transmission stiffness structure and assembly method for robots. Background Technology

[0002] Currently, as industrial robots develop towards higher speeds and precision, the joint structure of industrial robots using RV-C series reducers is becoming increasingly hot, leading to increased heat generation in the reducer due to motor heat. Therefore, increasing the distance between the motor and reducer can effectively prevent overheating of the reducer's lubricating oil. While this solves the heat problem, it results in an excessively long cantilever on the gear shaft mounted on the motor's output shaft. To address this, the current technology involves adding a bearing between the central gear of the RV-C series reducer and the motor housing. However, the assembly of the motor, bearing, gear shaft, and central shaft involves high-precision blind assembly in an area not visible within the casting. Existing bearing installations are large, have low precision, and cannot fundamentally solve the cantilever stiffness, vibration, and precision issues of the gear shaft drive. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a high transmission stiffness structure and assembly method for robots, thereby solving the issues of low blind assembly accuracy in unseen areas of RV-C series reducers and the problems of gear shaft cantilever stiffness, vibration, and accuracy.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An embodiment of the present invention provides a high transmission rigidity structure for a robot, including a motor, a gear shaft assembly, a casting, a reducer, and a bearing assembly. The casting is connected to the reducer, and there is an invisible area between the casting and the reducer. The bottom of the invisible area is provided with a bearing assembly. The gear shaft assembly is connected to the output shaft of the motor. The gear shaft assembly is inserted into the invisible area and is connected to the reducer for transmission. The end of the gear shaft assembly is supported by the bearing assembly.

[0006] In one possible implementation, the gear shaft assembly includes a gear shaft and a drive gear, wherein one end of the gear shaft is connected to the output shaft of the motor, and the other end is provided with a drive gear that meshes with the central gear of the reducer; the center of the drive gear is provided with a bearing mounting hole, and the bearing assembly is accommodated in the bearing mounting hole.

[0007] In one possible implementation, the other end of the gear shaft has an internal countersunk hole along the axis that communicates with the bearing mounting hole, and the sidewall of the internal countersunk hole has a radial hole for lubricating oil to pass through.

[0008] In one possible implementation, the outer end of the bearing mounting hole is provided with a bearing mounting chamfer.

[0009] In one possible implementation, one end of the gear shaft has a blind hole along the axis, and the output shaft of the motor is mated to the blind hole.

[0010] In one possible implementation, the bearing assembly includes a bearing and a bearing retainer, the bearing being mounted on the casting via the bearing retainer, and the bearing axis being collinear with the drive gear axis of the drive gear.

[0011] In one possible implementation, the bearing retainer includes a mandrel, a pressure washer, and a screw; the bearing is fitted onto the mandrel, the mandrel is connected to the casting via the pressure washer and the screw, and the inner ring of the bearing is axially limited by the pressure washer.

[0012] In one possible implementation, the reducer includes a housing and a central gear disposed within the housing, wherein the housing is sealed to the casting, and the central gear meshes with the drive gear.

[0013] In one possible implementation, the housing contains lubricating oil, with the oil level located at half the thickness of the central gear.

[0014] Based on the above design concept, another embodiment of the present invention provides an assembly method for the robot high transmission stiffness structure as described above, the assembly method comprising the following steps:

[0015] Step 1, state before blind installation: the gear shaft assembly, the center gear, and the bearing are separate from each other;

[0016] The second step is to connect the gear shaft assembly to the output shaft of the motor, and then insert the gear shaft assembly from top to bottom into the invisible area left between the casting and the reducer, so that the drive gear of the gear shaft assembly is aligned with the center gear in phase and height.

[0017] The third step, blind assembly status: the phase of the drive gear and the center gear are aligned, but the height part is not completely aligned at this time, and the drive gear and the bearing are in a separate state.

[0018] Fourth, the gear shaft assembly continues to move downwards until the height of the drive gear and the center gear are aligned, and the bearing is fully inserted into the bearing mounting hole at the center of the drive gear, so that the drive gear axis, the motor stator axis and the bearing axis are collinear.

[0019] The advantages and beneficial effects of this invention are as follows: The robot high transmission stiffness structure and assembly method provided by this invention change the cantilever stiffness of the existing gear shaft transmission to the simply supported stiffness, which greatly improves the transmission stiffness and transmission accuracy, while reducing transmission vibration and transmission noise, ensuring meshing transmission at the correct position, and achieving high transmission efficiency.

[0020] The present invention provides a high transmission stiffness structure for robots. By designing the gear shaft hollow and incorporating radial holes, it facilitates the circulation of lubricating oil, resulting in good lubrication and improved heat dissipation.

[0021] The present invention provides an assembly method for a robot with high transmission rigidity structure. In the unseen area, the gears are assembled first and then the bearings, which facilitates blind assembly. The assembly accuracy is high through tactile force sensing.

[0022] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a schematic diagram of a high transmission stiffness structure for a robot according to the present invention;

[0026] Figure 2 This is a schematic diagram of the initial assembly stage of a robot high transmission stiffness structure according to the present invention.

[0027] Figure 3 This is a schematic diagram showing the assembled robot high transmission stiffness structure of the present invention.

[0028] In the diagram: 1-Motor, 101-Motor body, 102-Motor output shaft, 2-Gear shaft assembly, 201-Gear shaft, 202-Drive gear, 203-Bearing mounting hole, 204-Bearing mounting chamfer, 205-Internal countersunk hole, 206-Radial hole, 3-Casing, 4-Reducer, 401-Housing, 402-Center gear, 403-Lubricating oil level, 5-Bearing, 501-Inner ring, 502-Outer ring, 503-Ball, 6-Spindle, 7-Pressure pad, 8-Screw, 9-Drive gear axis, 10-Motor stator axis, 11-Bearing axis. Detailed Implementation

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] One embodiment of the present invention provides a high transmission stiffness structure for a robot, employing a simply supported structure, which significantly improves transmission stiffness and accuracy while reducing transmission vibration and noise, ensuring proper meshing and high transmission efficiency. See also Figure 1 As shown, the robot's high transmission rigidity structure includes a motor 1, a gear shaft assembly 2, a casting 3, a reducer 4, and a bearing assembly. The casting 3 is connected to the reducer 4, and there is an invisible area between the casting 3 and the reducer 4. The bottom of the invisible area is provided with a bearing assembly. The gear shaft assembly 2 is connected to the output shaft of the motor 1. The gear shaft assembly 2 is inserted into the invisible area and is connected to the reducer 4 for transmission. The end of the gear shaft assembly 2 is supported by the bearing assembly.

[0034] like Figure 2As shown in the embodiment of the present invention, the motor 1 includes a motor body 101 and a motor output shaft 102. The motor body 101 is connected to the housing of the reducer 4, and the motor output shaft 102 is connected to the gear shaft assembly 2. The gear shaft assembly 2 includes a gear shaft assembly 201 and a drive gear 202, wherein one end of the gear shaft assembly 201 is connected to the motor output shaft 102, and the other end is provided with the drive gear 202; the center of the drive gear 202 is provided with a bearing mounting hole 203, and the bearing assembly is accommodated in the bearing mounting hole 203.

[0035] Furthermore, one end of the gear shaft assembly 201 is provided with a blind hole along the axis. The motor output shaft 102 is connected to the blind hole and fixed by bolts. Alternatively, common mechanical parts such as keyways and screws can be used to connect with the gear shaft assembly 201, so that the drive gear axis 9 of the drive gear 202 is collinear with the motor stator axis 10 of the motor body 101. The gear shaft assembly 201 and the motor output shaft 102 share the same axis of rotation as the drive gear axis 9.

[0036] In an embodiment of the present invention, the other end of the gear shaft assembly 201 is provided with an internal countersunk hole 205 communicating with the bearing mounting hole 203 along the axial direction, and the sidewall of the internal countersunk hole 205 is provided with radial holes 206 for lubricating oil to pass through. In this embodiment, four radial holes 206 are provided circumferentially on the sidewall of the gear shaft assembly 201 to balance the lubricating oil and improve the heat dissipation effect.

[0037] like Figure 2 As shown, in an embodiment of the present invention, the bearing assembly includes a bearing 5 and a bearing fixing member. The bearing 5 is mounted on the casting 3 through the bearing fixing member, and the bearing axis 11 of the bearing 5 is collinear with the drive gear axis 9 of the drive gear 202.

[0038] In an embodiment of the present invention, the bearing fixing component includes a spindle 6, a pressure washer 7, and a screw 8; the bearing 5 is sleeved on the spindle 6, and the spindle 6 is connected to the casting 3 through the pressure washer 7 and the screw 8. The bearing 5 includes an inner ring 501, an outer ring 502, and balls 503 disposed between the inner ring 501 and the outer ring 502. The inner ring 501 is axially limited by the pressure washer 7, and the outer ring 502 is tightly fitted with the bearing mounting hole 203.

[0039] Furthermore, a bearing mounting chamfer 204 is provided on the outer end of the bearing mounting hole 203 to facilitate the smooth insertion of the bearing 5 into the bearing mounting hole 203.

[0040] In an embodiment of the present invention, the reducer 4 includes a housing 401 and a central gear 402 disposed within the housing 401. The housing 401 is sealed to the casting 3, and the central gear 402 meshes with the drive gear 202. Lubricating oil is provided inside the housing 401, with the oil level 403 located at half the thickness of the central gear 402. The center of the ball bearing 503 is below the oil level 403.

[0041] In this embodiment of the invention, the reducer 4 is an RV-C series reducer, which is a hollow internal wiring reducer for industrial robots. In actual use, due to the meshing transmission between the drive gear 202 of the gear shaft assembly 2 and the spur gear 402 of the reducer 4, the radial force generated by the gear transmission, combined with the stiffness factors of the internal bearings of the motor body 101 and the motor output shaft 102, causes the drive gear axis 9 and the motor stator axis 10 to be non-collinear. This non-collinearity means that the drive gear axis 9 is offset and skewed relative to the motor stator axis 10, which is commonly related to bending stiffness in mechanical transmission. In this embodiment, the bearing 5 is built into the center of the drive gear 202, so that the radial force generated between the drive gear 202 and the central gear 402 of the reducer 4 is applied to the bearing 5, improving bending stiffness and thus improving transmission accuracy.

[0042] The present invention provides a high transmission stiffness structure for robots, which changes the cantilever stiffness of the existing gear shaft transmission to simply supported stiffness, greatly improving the transmission stiffness and transmission accuracy, while reducing transmission vibration and transmission noise, ensuring meshing transmission at the correct position, and achieving high transmission efficiency.

[0043] Based on the above embodiments, another embodiment of the present invention provides an assembly method for a robot with high transmission stiffness, comprising the following steps:

[0044] Step 1, state before blind installation: Gear shaft assembly 2, center gear 402 and bearing 5 are separated from each other.

[0045] The second step is to connect the gear shaft assembly 2 to the output shaft of the motor 1, and then insert the gear shaft assembly 2 from top to bottom into the invisible area left between the casting 3 and the reducer 4, so that the drive gear 202 and the center gear 402 of the gear shaft assembly 2 are aligned in phase and height; the phase is defined as the initial angle of relative meshing between the drive gear 202 and the center gear 402, with a gap between the upper and lower parts of the skewed insertion.

[0046] The third step, as Figure 2 As shown, in the blind assembly state: the drive gear 202 and the center gear 402 are aligned in phase, but the height is not completely aligned. At this time, the drive gear 202 and the bearing 5 are separated from each other.

[0047] Step four, as Figure 3As shown, the gear shaft assembly 2 continues to move downwards. The bearing mounting chamfer 204 and bearing mounting hole 203 of the drive gear 202 guide each other to the outer ring 502 of the bearing 5. The drive gear 202 is aligned with the height of the central gear 402, and the bearing 5 is fully inserted into the bearing mounting hole 203 at the center of the drive gear 202, making the drive gear axis 9, the motor stator axis 10, and the bearing axis 11 collinear. The drive gear axis 9 changes from skewed to upright. At this time, the support bearing inside the central gear 402, the bearing 5, and the inner bearing between the motor body 101 and the motor output shaft 102 are pressed together to generate support rigidity.

[0048] During operation, due to the viscosity of the lubricating oil and the rotational unload, the lubricating oil in bearing 5 circulates through the internal countersunk hole 205 and radial hole 206, which facilitates heat dissipation and the formation of bearing support oil film stiffness.

[0049] This invention provides a high-transmission stiffness structure and assembly method for robots, enabling high-precision, high-rigidity, and low-vibration blind assembly in unseen areas. This significantly improves transmission stiffness and accuracy while reducing transmission vibration and noise, ensuring correct meshing and high transmission efficiency. Furthermore, the structure offers good lubrication and improved heat dissipation. During assembly, in the unseen area, the gears are aligned first (i.e., the phase and height of the drive gear 202 and the central gear 402 are determined), followed by the bearings (i.e., the bearing 5 is inserted into the central gear 402). This facilitates blind assembly, allows for tactile feedback, ensures high assembly accuracy, and improves assembly efficiency.

[0050] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method of assembling a robot high-transmission-rigidity structure, characterized by, The high transmission rigidity structure of the robot includes a motor (1), a gear shaft assembly (2), a casting (3), a reducer (4), and a bearing assembly. The casting (3) is connected to the reducer (4), and there is an invisible area between the casting (3) and the reducer (4). The bottom of the invisible area is provided with a bearing assembly. The gear shaft assembly (2) is connected to the output shaft of the motor (1). The gear shaft assembly (2) is inserted into the invisible area and is connected to the reducer (4) for transmission. The end of the gear shaft assembly (2) is supported by the bearing assembly. The gear shaft assembly (2) includes a gear shaft (201) and a drive gear (202), wherein one end of the gear shaft (201) is connected to the output shaft of the motor (1), and the other end is provided with a drive gear (202), which meshes with the center gear (402) of the reducer (4); the center of the drive gear (202) is provided with a bearing mounting hole (203), and the bearing assembly is housed in the bearing mounting hole (203); The other end of the gear shaft (201) is provided with an internal countersunk hole (205) communicating with the bearing mounting hole (203) along the axis, and the sidewall of the internal countersunk hole (205) is provided with a radial hole (206) for lubricating oil to pass through. The bearing assembly includes a bearing (5) and a bearing retainer. The bearing (5) is mounted on the casting (3) by the bearing retainer, and the bearing axis (11) of the bearing (5) is collinear with the drive gear axis (9) of the drive gear (202). The assembly method includes the following steps: Step 1, state before blind installation: the gear shaft assembly (2), the center gear (402) and the bearing (5) are separated from each other; The second step is to connect the gear shaft assembly (2) to the output shaft of the motor (1), and then insert the gear shaft assembly (2) from top to bottom into the invisible area left between the casting (3) and the reducer (4), so that the drive gear (202) of the gear shaft assembly (2) is aligned with the center gear (402) in phase and height. The third step, blind assembly state: the phase of the drive gear (202) and the center gear (402) are aligned, but the height part is not completely aligned at this time, and the drive gear (202) and the bearing (5) are separated from each other; In the fourth step, the gear shaft assembly (2) continues to move downward until the height of the drive gear (202) and the center gear (402) are aligned, and the bearing (5) is fully inserted into the bearing mounting hole (203) at the center of the drive gear (202), so that the drive gear axis (9), the motor stator axis (10) and the bearing axis (11) are collinear.

2. The assembly method of the robot high transmission stiffness structure according to claim 1, characterized in that, The outer end of the bearing mounting hole (203) is provided with a bearing mounting chamfer (204).

3. The assembly method of the robot high transmission stiffness structure according to claim 1, characterized in that, One end of the gear shaft (201) is provided with a blind hole along the axis, and the output shaft of the motor (1) is connected to the blind hole by insertion.

4. The assembly method of the robot high transmission stiffness structure according to claim 1, characterized in that, The bearing fixing component includes a spindle (6), a pressure pad (7), and a screw (8); the bearing (5) is sleeved on the spindle (6), the spindle (6) is connected to the casting (3) through the pressure pad (7) and the screw (8), and the inner ring (501) of the bearing (5) is axially limited by the pressure pad (7).

5. The assembly method of the robot high transmission stiffness structure according to claim 1, characterized in that, The reducer (4) includes a housing (401) and a central gear (402) disposed in the housing (401), wherein the housing (401) is sealed to the casting (3), and the central gear (402) meshes with the drive gear (202).

6. The assembly method of the robot high transmission stiffness structure according to claim 5, characterized in that, The housing (401) contains lubricating oil, and the lubricating oil level (403) is located at half the thickness of the central gear (402).

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