A robot motor assembly assembly tool and process

Abstract

The application belongs to the technical field of robot assembly, and particularly relates to a robot motor assembly assembly tool and process. The tool comprises a large screw, a small screw, a ball pair force transmission structure and a runout detection aid, the lower end of the large screw is sleeved on the outside of a motor shaft fixing ring; a gear shaft is inserted into the large screw, an assembly section is butted with a motor gear assembly hole, and a tooth section tooth top circle is slidingly matched with a small diameter hole of the large screw; the ball pair force transmission structure is arranged above the gear shaft, the small screw is matched with a thread hole of the large screw; by controlling the axial distance of the tail ends of the large and small screws, a preset assembly gap is formed between the inside gear end face of the gear shaft and the shaft end face of the motor shaft; the runout detection aid is used to obtain the tooth surface runout high point of the gear shaft and the motor gear assembly hole runout low point, and the tooth surface runout high point and the motor gear assembly hole runout low point are phase aligned and inserted. The application realizes runout phase compensation assembly, reduces the assembly runout, accurately controls the assembly gap, avoids part assembly deformation, and has high assembly precision.

Description

Technical Field

[0001] This invention belongs to the field of robot assembly technology, and specifically relates to a robot motor assembly fixture and process. Background Technology

[0002] The motor and output gear shaft assembly is a core component of industrial robots. From a mass production application perspective, the motion accuracy and tooth surface runout of the assembled motor and output gear shaft directly determine the positioning accuracy, vibration characteristics, noise level, and service life of the entire industrial robot. Due to limitations in mass production processing conditions, setting excessively strict tolerances for gear runout and motor shaft runout will result in the scrapping of a large number of components. For example, the runout requirement for the motor-gear shaft assembly is 29μm. When the gear runout or motor shaft runout exceeds 29μm, the component should be scrapped according to current process standards. However, motors and gears are high-value-added key components in the industrial robot field, and direct scrapping would significantly increase production costs. Therefore, how to assemble a motor-gear assembly with acceptable runout using motors and gears with excessive runout is a technical problem that urgently needs to be solved in the mass production process. Thus, a new technical solution is urgently needed to overcome the shortcomings of the existing technology. Summary of the Invention

[0003] To address the issue of high costs associated with scrapping high-value-added motors and gears of industrial robots due to excessive runout, this invention provides a robot motor assembly fixture and process that can assemble motors and gears with excessive runout to obtain motor-gear assemblies with acceptable runout.

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

[0005] This invention provides a robot motor assembly fixture for assembling a motor and a gear shaft. The fixture includes a large screw, a small screw, a motor shaft retaining ring, a cylindrical pin, a ball joint force transmission structure, and a runout detection tool. The motor shaft retaining ring is positioned and connected to the motor shaft of the motor. The large screw has a through hole at its center, which includes a threaded hole, a small-diameter hole, and a large-diameter hole arranged sequentially from top to bottom. The large-diameter hole of the large screw is fitted onto the outside of the motor shaft retaining ring and is positioned and connected to the motor shaft retaining ring via the cylindrical pin. The gear shaft includes an assembly section, a tooth section, a bearing section, and an externally threaded section arranged sequentially along the axial direction. The gear shaft is inserted into the large screw, and the assembly section mates with the motor gear assembly hole of the motor shaft. The teeth of the tooth section... The top circle and the small-diameter hole of the large screw form a sliding linear pair; the ball joint force transmission structure is arranged above the gear shaft, the small screw is threadedly engaged with the threaded hole of the large screw, the lower end of the small screw abuts against the ball joint force transmission structure, and rotating the small screw applies assembly pressure to the gear shaft; by controlling the axial distance between the tail ends of the small screw and the large screw, a preset assembly gap is formed between the inner gear end face of the gear shaft and the shaft end face of the motor shaft; the runout detection auxiliary tool is used to obtain the high point of the tooth surface runout of the gear shaft and the low point of the runout of the motor gear assembly hole, so that the high point of the tooth surface runout of the gear shaft and the low point of the runout of the motor gear assembly hole are aligned and interlocked during assembly to achieve complementary cancellation of runout errors.

[0006] The preset assembly gap between the inner gear end face of the gear shaft and the shaft end face of the motor shaft is 0.1mm to 0.2mm.

[0007] The axial distance between the small screw and the tail end of the large screw is measured using a depth gauge.

[0008] The ball joint force transmission structure includes a rotating component and a ball bearing. The rotating component is a cylindrical structure, and its outer cylindrical surface is clearance-fitted with the small-diameter hole of the large screw. The bottom of the rotating component has a lower circular surface that abuts against the upper end of the gear shaft. The top of the rotating component has an upper conical pit, and the ball bearing is placed in the upper conical pit to form a ball joint. The lower end of the small screw abuts against the ball bearing.

[0009] The motor shaft fixing ring is a split structure, including a first half-ring and a second half-ring. The first half-ring and the second half-ring have the same structure, both including a half-ring body. The inner side of the half-ring body is provided with a shaft hole and a small hole along the axial direction. The inner wall of the shaft hole is provided with a half-shaft clip along the circumferential direction. The shaft hole mates with the motor shaft, and the half-shaft clip fills the annular groove of the motor shaft. The side wall of the small hole is provided with a radial pin hole.

[0010] The cylindrical pin includes a first internal thread cylindrical pin and a second internal thread cylindrical pin, which are arranged opposite to each other and pass through the pin hole on the large screw and the radial pin hole of the motor shaft fixing ring in sequence.

[0011] The assembly section of the gear shaft is divided into a clearance guide section and an interference fit section by a tolerance transition line; by controlling the ratio of the interference fit section (210) to the clearance guide section (208), the slippage torque of the interference fit between the gear shaft and the motor shaft is 3-5 times the rated torque of the motor.

[0012] The runout detection aids include a gear shaft tooth surface runout gauge and a motor shaft hole runout gauge;

[0013] The gear shaft tooth surface runout inspection tool includes a first detection V-weight, a detection pin, a dial indicator, and a second detection V-weight. The first and second detection V-weights are arranged side by side and are used to support both ends of the gear shaft, respectively. The detection pin is placed between two teeth of the gear shaft and contacts the meshing surfaces of the two teeth. The runout high point of the detection pin is detected by the dial indicator and recorded as the first high point. The high point detection of all tooth grooves is completed in sequence, the highest runout point is selected, and the tooth groove position corresponding to the highest runout is marked.

[0014] The motor shaft hole runout gauge includes a oscillating dial indicator. By rotating the motor and using the oscillating head of the oscillating dial indicator to press against the motor gear assembly hole, the low point of runout of the motor gear assembly hole can be detected.

[0015] Another aspect of the present invention provides a robot motor assembly process based on the tooling described above, comprising the following steps:

[0016] S1: Marks the highest point of tooth surface runout of the gear shaft;

[0017] S2: Marks the lowest point of runout of the motor gear mounting hole;

[0018] S3: Align the high point of the tooth surface runout of the gear shaft with the low point of the runout of the motor gear assembly hole in phase and then insert them so that the axial tolerance transition line of the assembly section of the gear shaft is exactly locked at the entrance position of the motor gear assembly hole.

[0019] S4: Assembly tooling and other components;

[0020] S5: Use two wrenches to tighten the large screw and the small screw respectively, and use a depth gauge to control the axial distance between the tail ends of the large screw and the small screw, so that an assembly gap of 0.1mm to 0.2mm is formed between the inner gear end face of the gear shaft and the shaft end face of the motor.

[0021] In step S1, a gear shaft tooth surface runout gauge is used to obtain and mark the highest point of tooth surface runout of the gear shaft; the two ends of the gear shaft are supported by the first detection V iron and the second detection V iron respectively, and the detection pin is placed between the two teeth of the gear shaft and in contact with the meshing surface of the tooth surface. The highest point of tooth surface runout is obtained by detecting tooth by tooth using a dial indicator and then marked.

[0022] In step S2, the motor shaft is rotated, and a oscillating dial indicator is used to detect the motor gear assembly hole to obtain and mark the lowest point of runout of the motor shaft hole.

[0023] In step S4, the steps for assembling the remaining parts of the tooling are as follows:

[0024] S41: The ball joint force transmission structure is placed on the upper end face of the gear shaft, and the lower end face of the ball joint force transmission structure is in contact with the upper end face of the gear shaft to ensure that the pressure can be transmitted downward evenly and to avoid uneven load during the pressing process.

[0025] S42: Insert the large screw from above the gear shaft. The small-diameter hole inside the large screw is adapted to the outer periphery of the ball joint force transmission structure. The lower end of the large screw is fitted on the outside of the motor shaft retaining ring, so that the pin hole of the large screw is radially aligned with the radial pin hole of the motor shaft retaining ring.

[0026] S43: Insert the cylindrical pins sequentially into the pin holes of the large screw and the radial pin holes of the motor shaft retaining ring to achieve circumferential positioning between the large screw and the motor shaft retaining ring, restrict the circumferential rotation of the large screw, and ensure that the phase will not shift during the assembly process.

[0027] S44: Screw the small screw into the threaded hole of the large screw, so that the lower end of the small screw abuts against the upper end face of the ball joint force transmission structure; at this time, the small screw has not yet applied the press load, only completed the pre-contact, and retains the axial adjustment margin for subsequent press fitting and clearance control.

[0028] The present invention has the following beneficial effects and advantages:

[0029] 1. In the entire assembly process of this invention, neither the outer gear end face 206 nor the inner gear end face 205 at either end of the tooth segment 202 of the gear shaft 2 comes into contact with any solid component. In the prior art assembly process, the outer gear end face 206 is pressed, and after the gear has been quenched, fatigue microcracks are easily generated under pressure; this invention can effectively avoid the occurrence of this defect.

[0030] 2. By controlling the axial distance between the large screw 3 and the tail end of the small screw 4, for example by using a depth gauge, the present invention creates an assembly gap of 0.1mm to 0.2mm between the inner gear end face 205 and the shaft end face 104 of the motor 1, thereby preventing fatigue cracks from forming at the end face position after the gear teeth are quenched.

[0031] 3. In this invention, the external thread section 204 of the gear shaft 2 is used to achieve the disassembly and separation between the gear shaft 2 and the motor 1; the bearing section 203 can be installed into the inner hole of the auxiliary bearing, thereby improving the gear meshing stiffness. The tooth tip circle of the tooth section 202 and the small hole 302 of the large screw form a sliding linear pair, which can solve the problem of pressure rod instability when pressing the gear shaft 2 and avoid the risk of microcracks in the gear quenching layer induced by the bending stress generated by pressing.

[0032] 4. This invention can appropriately relax the mass production tolerances for gear runout and motor shaft runout. In existing solutions, the runout requirement for motor-gear shaft assemblies is 29μm. When the gear runout or motor shaft runout exceeds 29μm, the components are usually scrapped. However, motors and gears are high-value-added key components of industrial robots, and scrapping them would result in resource waste. This invention can pair and assemble motors and gears with excessive runout to obtain motor-gear assemblies with acceptable runout. For example, if the motor shaft runout is 35μm and the gear shaft runout is 33μm, both exceeding the 29μm single-piece requirement, after assembly using this invention, the overall runout of the assembly can reach 27μm, meeting the requirements for post-assembly use.

[0033] 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.

[0034] 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

[0035] 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:

[0036] Figure 1 This is an isometric view of a robot motor assembly fixture according to the present invention;

[0037] Figure 2 This is a cross-sectional view of a robot motor assembly fixture according to the present invention;

[0038] Figure 3 for Figure 2 A magnified view of part A;

[0039] Figure 4 This is an isometric view of the gear shaft in this invention;

[0040] Figure 5 This is one of the structural schematic diagrams of the first semi-ring component in this invention;

[0041] Figure 6 This is the second schematic diagram of the structure of the first semi-ring component in this invention;

[0042] Figure 7 This is a schematic diagram of the test of the high point of tooth surface runout of the gear shaft in an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the low point test of the motor shaft hole in an embodiment of the present invention.

[0044] In the diagram: 1. Motor; 101. Motor shaft; 102. Motor gear assembly hole; 103. Annular groove; 104. Motor shaft end face; 105. Assembly chamfer; 2. Gear shaft; 201. Assembly section; 202. Gear section; 203. Bearing section; 204. External thread section; 205. Inner gear end face; 206. Outer gear end face; 207. Spiral vent groove; 208. Clearance guide section; 209. Interference fit section; 210. Tolerance transition line; 3. Large screw; 301. Threaded hole; 302. Small diameter hole; 303. Large diameter hole 304. Radial hole; 305. Hexagonal head; 4. Small screw; 5. First semi-ring; 501. Semi-ring body; 502. Radial pin hole; 503. Half-shaft clip; 504. Shaft hole; 505. Small hole; 6. Second semi-ring; 7. First internal thread cylindrical pin; 8. Second internal thread cylindrical pin; 9. Rotating part; 901. Outer cylindrical surface; 902. Upper conical pit; 903. Lower cylindrical surface; 10. Ball bearing; 11. First detection V-iron; 12. Detection pin; 13. Dial indicator; 14. Second detection V-iron; 16. Oscillating dial indicator. Detailed Implementation

[0045] 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.

[0046] 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.

[0047] See Figures 1 to 8As shown, an embodiment of the present invention provides a robot motor assembly fixture for assembling a motor 1 and a gear shaft 2. The fixture includes a large screw 3, a small screw 4, a motor shaft retaining ring, a cylindrical pin, a ball joint force transmission structure, and a runout detection tool. The motor shaft retaining ring is positioned and connected to the motor shaft 101 of the motor 1. The large screw 3 has a hexagonal head 305 at its head and a through hole at its center. The through hole includes a threaded hole 301, a small-diameter hole 302, and a large-diameter hole 303 arranged sequentially from top to bottom. The large-diameter hole 303 of the large screw 3 is fitted onto the outside of the motor shaft retaining ring and is positioned and connected to the motor shaft retaining ring by the cylindrical pin. The gear shaft 2 includes an assembly section 201, a tooth section 202, a bearing section 203, and an external thread section 204 arranged sequentially along the axial direction. The tooth section 202 has an outer gear end face 206 and an inner gear end face 205 at both ends. The gear shaft 2 is inserted... The assembly section 201 is located inside the large screw 3 and mates with the motor gear assembly hole 102 of the motor shaft 101. The tooth tip circle of the tooth section 202 and the small diameter hole 302 of the large screw 3 form a sliding linear pair. The ball joint force transmission structure is arranged above the gear shaft 2. The small screw 4 is threaded into the threaded hole 301 of the large screw 3. The lower end of the small screw 4 abuts against the ball joint force transmission structure. Rotating the small screw 4 applies assembly pressure to the gear shaft 2. By controlling the axial distance between the tail ends of the small screw 4 and the large screw 3, a preset assembly gap is formed between the inner gear end face 205 of the gear shaft 2 and the shaft end face 104 of the motor shaft 101. The runout detection auxiliary tool is used to obtain the high point of the tooth surface runout of the gear shaft 2 and the low point of the runout of the motor gear assembly hole 102, so that the high point of the tooth surface runout of the gear shaft 2 and the low point of the runout of the motor gear assembly hole 102 are aligned and interlocked during assembly to achieve complementary cancellation of runout errors.

[0048] Preferably, the axial distance between the tail ends of the small screw 4 and the large screw 3 is measured using a depth gauge; the preset assembly gap between the inner gear end face 205 of the gear shaft 2 and the shaft end face 104 of the motor shaft 101 is 0.1mm to 0.2mm to avoid fatigue cracks on the end face of the gear teeth after quenching. Throughout the entire process of this invention, neither the outer gear end face 206 nor the inner gear end face 205 at either end of the gear segment 202 comes into contact with other solid components. Existing technologies typically apply pressure to the outer gear end face 206, and after quenching, the gear is prone to fatigue microcracks under pressure; this invention avoids this problem.

[0049] See Figure 3As shown, in an embodiment of the present invention, the ball joint force transmission structure includes a rotating component 9 and a ball 10. The rotating component 9 is a cylindrical structure, and its outer cylindrical surface 901 is clearance-fitted with the small diameter hole 302 of the large screw 3. The bottom of the rotating component 9 is provided with a lower circular surface 903, which abuts against the upper end of the gear shaft 2. The top of the rotating component 9 is provided with an upper conical pit 902, and the ball 10 is placed in the upper conical pit 902 to form a ball joint. The lower end of the small screw 4 abuts against the ball 10.

[0050] See Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown in the embodiment of the present invention, the motor shaft fixing ring is a split structure, including a first half-ring 5 and a second half-ring 6. The first half-ring 5 and the second half-ring 6 have the same structure, both including a half-ring body 501. The inner side of the half-ring body 501 is provided with a shaft hole 504 and a small hole 505 along the axial direction. The inner wall of the shaft hole 504 is provided with a half-shaft clip 503 along the circumferential direction. The shaft hole 504 cooperates with the motor shaft 101, and the half-shaft clip 503 fills into the annular groove 103 of the motor shaft 101 to form axial and radial positioning. The side wall of the small hole 505 is provided with a radial pin hole 502, and the small hole 505 provides machining depth space for the radial pin hole 502.

[0051] Specifically, the cylindrical pin includes a first internal thread cylindrical pin 7 and a second internal thread cylindrical pin 8. The first internal thread cylindrical pin 7 and the second internal thread cylindrical pin 8 are arranged opposite to each other, and each cylindrical pin passes through the pin hole provided on the large screw 3 and the radial pin hole 502 of the motor shaft fixing ring in sequence.

[0052] See Figure 4 As shown, the assembly section 201 of the gear shaft 2 is divided into a clearance guide section 208 and an interference fit section 209 by a tolerance transition line 210. By controlling the ratio of the interference fit section 210 to the clearance guide section 208, the slippage torque of the interference fit between the gear shaft 2 and the motor shaft 101 is 3-5 times the rated torque of the motor. The peak operating torque of the industrial robot motor is 3.1 times the rated torque. This torque setting ensures that the motor and reducer are not damaged in the event of an accidental collision with the industrial robot, and the robot can continue to be used after zero-position calibration.

[0053] Furthermore, the outer surface of the assembly section 201 of the gear shaft 2 is provided with a spiral exhaust groove 207, and the spiral exhaust hole 207 is used for exhausting the motor gear assembly hole 102 after assembly.

[0054] Specifically, the external thread section 204 of the gear shaft 2 is used to facilitate the disassembly of the gear shaft 2 from the motor 1; the bearing section 203 can extend into the inner hole of the auxiliary bearing to improve the gear meshing rigidity. The tooth tip circle of the tooth section 202 and the small diameter hole 302 of the large screw form a sliding linear pair, which can eliminate the instability of the pressure rod during the press-fitting of the gear shaft 2 and avoid micro-cracks in the gear quenching layer induced by the bending stress during press-fitting.

[0055] Furthermore, the end of the motor gear mounting hole 102 is provided with a mounting chamfer 105 to prevent collisions when assembling the gear shaft 2.

[0056] Due to factors such as processing technology and heat treatment, the gear shaft 2 will have runout error relative to the bearing section 203 and the assembly section 201. Therefore, it is necessary to calibrate the high point of runout of the gear shaft 2.

[0057] In embodiments of the present invention, the runout detection auxiliary tool includes a gear shaft tooth surface runout gauge and a motor shaft hole runout gauge; see also Figure 7 As shown, the gear shaft tooth surface runout inspection tool includes a first detection V-bolt 11, a detection pin 12, a dial indicator 13, and a second detection V-bolt 14. The first detection V-bolt 11 and the second detection V-bolt 14 are arranged side by side and are used to support the two ends of the gear shaft 2, respectively. The detection pin 12 is placed between two teeth of the gear shaft 2 and is in contact with the meshing surfaces of the teeth on both sides. The high point of the runout of the detection pin 12 is detected by the dial indicator 13 and recorded as the first high point. The high point detection of all tooth grooves is completed in sequence, the highest runout point is selected, and the tooth groove position corresponding to the highest runout is marked.

[0058] See Figure 8 As shown, the motor shaft hole runout gauge includes a oscillating dial indicator 16; to detect the low point of runout in the motor gear assembly hole 102: drive the motor 1 to rotate, and use the oscillating head of the oscillating dial indicator 16 to press against the motor gear assembly hole 102 to detect the position of the low point of runout in the motor gear assembly hole 102.

[0059] This invention provides a robot motor assembly fixture that can achieve phase compensation assembly for high and low points of runout between the gear shaft and the motor assembly hole, effectively reducing the overall runout of the component. The assembly process can precisely control the end face assembly gap, avoid deformation of parts under pressure, and achieve stable assembly phase and high assembly accuracy.

[0060] See Figures 1 to 8 As shown, another embodiment of the present invention provides a robot motor assembly process based on the tooling described above, including the following steps:

[0061] S1: Mark the highest point of tooth surface runout of gear shaft 2;

[0062] S2: Mark the low point of runout of the motor gear mounting hole 102 of motor 1;

[0063] S3: Align the high point of the tooth surface runout of the gear shaft 2 with the low point of the runout of the motor gear assembly hole 102 in phase and then insert them so that the tolerance transition line 210 of the assembly section 201 of the gear shaft 2 is exactly positioned at the entrance of the motor gear assembly hole 102.

[0064] S4: Assembly tooling and other components;

[0065] S5: Use two wrenches to tighten the large screw 3 and the small screw 4 respectively, and control the axial distance between the tail ends of the large screw 3 and the small screw 4 with a depth gauge to form an assembly gap of 0.1mm to 0.2mm between the inner gear end face 205 of the gear shaft 2 and the shaft end face 104 of the motor 1.

[0066] In step S1, a gear shaft tooth surface runout gauge is used to obtain and mark the high point of tooth surface runout of gear shaft 2; the two ends of gear shaft 2 are supported by the first detection V iron 11 and the second detection V iron 14 respectively, and the detection pin 12 is placed between the two teeth of gear shaft 2 and in contact with the meshing surface of the tooth surface. The highest point of tooth surface runout is obtained by detecting tooth by tooth using a dial indicator 13 and marked.

[0067] In step S2, the motor shaft 101 is rotated, and the motor gear assembly hole 102 is detected by the oscillating dial indicator 16 to obtain and mark the low point of the runout of the motor shaft hole.

[0068] In step S4, the steps for assembling the remaining parts of the tooling are as follows:

[0069] S41: The ball joint force transmission structure is placed on the upper end face of the gear shaft 2, and the lower end face of the ball joint force transmission structure is in contact with the upper end face of the gear shaft 2 to ensure that the pressure can be transmitted downward evenly and to avoid uneven load during the pressing process.

[0070] S42: Insert the large screw 3 from above the gear shaft 2. The small diameter hole 302 inside the large screw 3 is adapted to the outer periphery of the ball joint force transmission structure. The lower end of the large screw 3 is fitted on the outside of the motor shaft fixing ring, so that the pin hole of the large screw 3 is radially aligned with the radial pin hole 502 of the motor shaft fixing ring.

[0071] S43: Insert the cylindrical pins sequentially into the pin holes of the large screw 3 and the radial pin holes 502 of the motor shaft fixing ring to achieve circumferential positioning between the large screw 3 and the motor shaft fixing ring, restrict the circumferential rotation of the large screw 3, and ensure that the phase will not shift during the assembly process.

[0072] S44: Screw the small screw 4 into the threaded hole 301 of the large screw 3, so that the lower end of the small screw 4 abuts against the upper end face of the ball joint force transmission structure; at this time, the small screw 4 has not yet applied the press-fit load, only completed the pre-contact, and retained the axial adjustment margin for subsequent press-fitting and clearance control.

[0073] The assembly process of this invention uses a runout detection tool to obtain the high point of runout on the gear shaft tooth surface and the low point of runout on the motor gear assembly hole. High and low point phase alignment and interlocking are used to achieve complementary compensation of runout errors, effectively reducing the overall runout of the component. During the press-fitting process, the ball joint force transmission structure and the sliding linear pair formed by the tooth tip circle and the small-diameter hole of the large screw eliminate the instability and bending stress of the pressure rod. The end faces of the gears are not subjected to press-fitting compression, and the assembly gap between the inner gear end face and the motor shaft end face is strictly controlled at 0.1mm to 0.2mm, which can avoid fatigue micro-cracks in the quenched gears. At the same time, the slippage torque is controlled to 3-5 times the rated torque of the motor by adjusting the ratio of the interference fit section to the clearance guide section. This protects the motor and reducer in the event of an accidental collision with the robot. After zero-position calibration, it can be put back into use. The assembly process has high precision and good reliability.

[0074] 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 robot motor assembly fixture for assembling a motor (1) and a gear shaft (2), characterized in that, The tooling includes a large screw (3), a small screw (4), a motor shaft retaining ring, a cylindrical pin, a ball joint force transmission structure, and a runout detection tool. The motor shaft retaining ring is positioned and connected to the motor shaft (101) of the motor (1). The large screw (3) has a through hole in its center. The through hole includes a threaded hole (301), a small diameter hole (302), and a large diameter hole (303) arranged sequentially from top to bottom. The large diameter hole (303) of the large screw (3) is fitted onto the outside of the motor shaft retaining ring and is positioned and connected to the motor shaft retaining ring by a cylindrical pin. The gear shaft (2) includes an assembly section (201), a gear section (202), a bearing section (203), and an external thread section (204) arranged sequentially along the axial direction. The gear shaft (2) is inserted into the large screw (3), and the assembly section (201) is connected to the motor gear assembly hole (102) of the motor shaft (101). The tooth tip circle of the gear section (202) is connected to the large screw. (3) The small diameter hole (302) forms a sliding linear pair; the ball pair force transmission structure is arranged above the gear shaft (2), the small screw (4) is threadedly engaged with the threaded hole (301) of the large screw (3), the lower end of the small screw (4) abuts against the ball pair force transmission structure, and the small screw (4) is rotated to apply assembly pressure to the gear shaft (2); by controlling the axial distance between the tail ends of the small screw (4) and the large screw (3), a preset assembly gap is formed between the inner gear end face (205) of the gear shaft (2) and the shaft end face (104) of the motor shaft (101); the runout detection auxiliary tool is used to obtain the high point of the tooth surface runout of the gear shaft (2) and the low point of the runout of the motor gear assembly hole (102) respectively, so that the high point of the tooth surface runout of the gear shaft (2) and the low point of the runout of the motor gear assembly hole (102) are aligned and interlocked during assembly to achieve complementary cancellation of runout errors.

2. The robot motor assembly fixture according to claim 1, characterized in that, The axial distance between the small screw (4) and the tail end of the large screw (3) is measured by a depth gauge; the preset assembly gap between the inner gear end face (205) of the gear shaft (2) and the shaft end face (104) of the motor shaft (101) is 0.1mm to 0.2mm.

3. The robot motor assembly fixture according to claim 1, characterized in that, The ball joint force transmission structure includes a rotating component (9) and a ball (10). The rotating component (9) is a cylindrical structure, and its outer cylindrical surface (901) is clearance-fitted with the small diameter hole (302) of the large screw (3). The bottom of the rotating component (9) is provided with a lower circular surface (903), which abuts against the upper end of the gear shaft (2). The top of the rotating component (9) is provided with an upper conical pit (902), and the ball (10) is placed in the upper conical pit (902) to form a ball joint. The lower end of the small screw (4) abuts against the ball (10).

4. The robot motor assembly fixture according to claim 1, characterized in that, The motor shaft fixing ring is a split structure, including a first half-ring (5) and a second half-ring (6). The first half-ring (5) and the second half-ring (6) have the same structure, both including a half-ring body (501). The inner side of the half-ring body (501) is provided with a shaft hole (504) and a small hole (505) along the axial direction. The inner wall of the shaft hole (504) is provided with a half-shaft clip (503) along the circumferential direction. The shaft hole (504) cooperates with the motor shaft (101), and the half-shaft clip (503) fills into the annular groove (103) of the motor shaft (101). The side wall of the small hole (505) is provided with a radial pin hole (502).

5. The robot motor assembly fixture according to claim 4, characterized in that, The cylindrical pin includes a first internal thread cylindrical pin (7) and a second internal thread cylindrical pin (8). The first internal thread cylindrical pin (7) and the second internal thread cylindrical pin (8) are arranged opposite to each other and pass through the pin hole on the large screw (3) and the radial pin hole (502) of the motor shaft fixing ring in sequence.

6. The robot motor assembly fixture according to claim 1, characterized in that, The assembly section (201) of the gear shaft (2) is divided into a clearance guide section (208) and an interference fit section (209) by a tolerance transition line (210). By controlling the ratio of the interference fit section (210) to the clearance guide section (208), the slippage torque of the interference fit between the gear shaft (2) and the motor shaft (101) is 3-5 times the rated torque of the motor.

7. The robot motor assembly fixture according to claim 1, characterized in that, The runout detection aids include a gear shaft tooth surface runout gauge and a motor shaft hole runout gauge; The gear shaft tooth surface runout inspection tool includes a first detection V-bolt (11), a detection pin (12), a dial indicator (13), and a second detection V-bolt (14). The first detection V-bolt (11) and the second detection V-bolt (14) are arranged side by side and are used to support the two ends of the gear shaft (2). The detection pin (12) is placed between two teeth of the gear shaft (2) and contacts the meshing surfaces of the two teeth. The high point of the runout of the detection pin (12) is detected by the dial indicator (13) and recorded as the first high point. The high point detection of all tooth grooves is completed in sequence, the highest runout point is obtained by screening, and the tooth groove position corresponding to the highest runout is marked. The motor shaft hole runout gauge includes a swing dial indicator (16). When the motor (1) is rotated, the swing head of the swing dial indicator (16) is pressed against the motor gear assembly hole (102) to detect the low point of runout of the motor gear assembly hole (102).

8. A robot motor assembly process based on the tooling described in claim 7, characterized in that, Includes the following steps: S1: Mark the highest point of tooth surface runout of gear shaft (2); S2: Mark the low point of the runout of the motor gear assembly hole (102) of the motor (1); S3: Align the high point of the tooth surface runout of the gear shaft (2) with the low point of the runout of the motor gear assembly hole (102) according to the phase and then insert them so that the tolerance transition line (210) of the assembly section (201) of the gear shaft (2) is exactly locked at the entrance position of the motor gear assembly hole (102). S4: Assembly tooling and other components; S5: Use two wrenches to tighten the large screw (3) and the small screw (4) respectively. Control the axial distance between the tail ends of the large screw (3) and the small screw (4) with a depth gauge so that an assembly gap of 0.1mm to 0.2mm is formed between the inner gear end face (205) of the gear shaft (2) and the shaft end face (104) of the motor (1).

9. The robot motor assembly process according to claim 8, characterized in that, In step S1, the high point of tooth surface runout of the gear shaft (2) is obtained and marked using a gear shaft tooth surface runout gauge; the two ends of the gear shaft (2) are supported by the first detection V iron (11) and the second detection V iron (14) respectively, and the detection pin (12) is placed between the two teeth of the gear shaft (2) and in contact with the meshing surface of the tooth surface. The highest point of tooth surface runout is obtained by detecting tooth by tooth using a dial indicator (13) and marked. In step S2, the motor shaft (101) is rotated, and the motor gear assembly hole (102) is detected by a oscillating dial indicator (16) to obtain and mark the low point of the runout of the motor shaft hole.

10. The robot motor assembly process according to claim 8, characterized in that, In step S4, the steps for assembling the remaining parts of the tooling are as follows: S41: The ball pair force transmission structure is placed on the upper end face of the gear shaft (2), and the lower end face of the ball pair force transmission structure is in contact with the upper end face of the gear shaft (2) to ensure that the pressure can be transmitted downward evenly and to avoid uneven load during the pressing process. S42: Insert the large screw (3) from above the gear shaft (2). The small diameter hole (302) inside the large screw (3) is adapted to the outer periphery of the ball joint force transmission structure. The lower end of the large screw (3) is fitted on the outside of the motor shaft fixing ring, so that the pin hole of the large screw (3) is radially aligned with the radial pin hole (502) of the motor shaft fixing ring. S43: Insert the cylindrical pins into the pin holes of the large screw (3) and the radial pin holes (502) of the motor shaft fixing ring in sequence to achieve circumferential positioning between the large screw (3) and the motor shaft fixing ring, restrict the circumferential rotation of the large screw (3), and ensure that the phase will not shift during the assembly process. S44: Screw the small screw (4) into the threaded hole (301) of the large screw (3) so that the lower end of the small screw (4) abuts against the upper end face of the ball joint force transmission structure; at this time, the small screw (4) has not yet applied the press load, only completed the pre-contact, and retained the axial adjustment margin for subsequent press fitting and clearance control.

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