A machine and method for assembling a bearing for a rotor shaft of an in-line motor

Abstract

This invention relates to a machine and method for assembling bearings on the rotor shaft of a mid-drive motor, comprising a bearing positioning seat, a transverse unit, a pressing bracket, a press, a pressing plate, and a rotor shaft positioning plate. The bearing positioning seat moves between a receiving position and a pressing position via the transverse unit, and has a stepped position to accommodate two bearings, with an internal support cylinder containing a special partition plate. The rotor shaft positioning plate has a positioning fixture and openings, and its height can be adjusted by the cylinder. The pressing plate is driven by the press. During assembly, the two bearings are first placed into the bearing positioning seat in sequence, and the partition plate of the internal support cylinder is used to radially tension and position the two bearings before pressing. The rotor shaft and the upper bearing are manually placed in the positioning fixture. After adjusting the height for alignment, the bearing positioning seat moves to the pressing position. The press drives the pressing plate to press down for pressing. This achieves semi-automatic, high coaxiality, and damage-free pressing of the upper, middle, and lower bearings of the rotor shaft of a mid-drive motor, significantly improving assembly efficiency and quality consistency.

Description

Technical Field

[0001] This invention relates to the field of mid-drive motor rotor shaft bearing assembly technology, and more specifically, to a mid-drive motor rotor shaft bearing assembly machine and method. Background Technology

[0002] Mid-drive motors are core drive components in electric bicycles, electric motorcycles, and other similar vehicles, and their performance and reliability directly affect the vehicle's power output and lifespan. Mid-drive motors typically employ a hollow shaft structure, with the rotor shaft being cylindrical. Multiple bearings are press-fitted inside to achieve stable high-speed operation. A typical rotor shaft usually has one bearing press-fitted at the top, and two more bearings are press-fitted axially in the middle of the shaft. The axes of these three bearings must be strictly coaxial, and the pressing process must not damage the mating surfaces of the bearings or the shaft.

[0003] Currently, the industry mostly uses manual or semi-automatic methods to assemble bearings on the rotor shaft of mid-drive motors. The common practice is to first fix the rotor shaft, and then press the bearings into the shaft one by one. This method has the following significant drawbacks: Low assembly efficiency: The three bearings need to be press-fitted in three separate steps, resulting in a long operation cycle.

[0004] Coaxiality is difficult to guarantee: repeated clamping and pressing can easily lead to cumulative errors, causing the axes of the three bearings to be non-collinear, affecting the rotor's dynamic balance and running stability, and generating vibration and noise.

[0005] Risk of bearing damage: When pressing two closely spaced bearings in the middle, the lack of effective separation and guidance measures can easily cause the bearings to become misaligned or stuck during the pressing process, thereby scratching the journal or damaging the bearing raceway.

[0006] Low level of automation: There is a lot of manual intervention, the labor intensity is high, the assembly quality is highly dependent on the worker's skills, and the consistency is poor.

[0007] Therefore, there is an urgent need for a special equipment and method that can achieve efficient, high-precision, and automated press-fitting of multi-bearing rotor shafts in mid-drive motors. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a mid-drive motor rotor shaft bearing assembly machine and a mid-drive motor rotor shaft bearing assembly method, in view of the above-mentioned defects of the prior art.

[0009] The technical solution adopted by this invention to solve its technical problem is: A mid-mounted motor rotor shaft bearing assembly machine is constructed, comprising a bearing positioning seat, a lateral movement unit for driving the bearing positioning seat to move laterally, and a pressing bracket; a press, a pressing plate, and a rotor shaft positioning plate are sequentially arranged from top to bottom on the pressing bracket; both the pressing plate and the rotor shaft positioning plate are longitudinally slidably arranged on the pressing bracket, the pressing plate is driven to move longitudinally by the press, and a height adjusting cylinder is provided on the rotor shaft positioning plate to adjust its height position; The bearing positioning seat has a receiving position and a pressing position in its lateral travel; the central motor rotor shaft bearing assembly machine also includes a bearing feeding assembly for feeding the bearing positioning seat bearing at the receiving position; the rotor shaft positioning plate is provided with an opening for the bearing positioning seat to extend from bottom to top and a positioning fixture for positioning the rotor shaft located at the edge of the opening; the pressing position is located directly below the opening; The bearing positioning seat has an installation groove on its upper surface, and an inner support cylinder is installed in the installation groove. The two inner support arms of the inner support cylinder are both inverted L-shaped. The opening of the installation groove has a first slot for the lateral side of the inner support arm to extend out. The outer surface of the upper end of the bearing positioning seat has a step for accommodating two bearings. The outer surface of the longitudinal side of the inner support arm has a rubber partition for inserting between the two bearings on the step. The inner wall of the installation groove has a second slot for the partition to extend out, and the second slot is connected to the step.

[0010] The mid-mounted motor rotor shaft bearing assembly machine of the present invention, wherein the two inner support arms of the inner support cylinder have a retracted state, a first open state and a second open state; In the retracted state, both inner support arms are retracted into the mounting slots, and the partition plate is located within the second slot; In the first open state, the lateral edges of the two inner support arms enter the first slot, and the end of the partition plate extends out of the second slot; In the second open state, the lateral edges of the two inner support arms extend out of the first slot, and the middle part of the partition plate extends out of the second slot.

[0011] The present invention relates to a mid-mounted motor rotor shaft bearing assembly machine, wherein the end and the middle of the partition plate are both flat, and the thickness of the end of the partition plate is less than the thickness of the middle of the partition plate.

[0012] The mid-mounted motor rotor shaft bearing assembly machine of the present invention has a transition arc surface provided at the connection between the end of the partition plate and the middle part of the partition plate.

[0013] The present invention relates to a mid-mounted motor rotor shaft bearing assembly machine, wherein a deformable stainless steel sheet is embedded inside the partition plate.

[0014] The present invention discloses a mid-mounted motor rotor shaft bearing assembly machine, wherein the press-fitting bracket includes a mounting base plate, a mounting top plate, and multiple connecting columns; the connecting columns connect the mounting base plate and the mounting top plate; the press is mounted on the mounting top plate, and the transverse movement unit is mounted on the mounting base plate; both the press-fitting plate and the rotor shaft positioning plate are provided with multiple guide sleeves that cooperate with the connecting columns.

[0015] The present invention relates to a mid-mounted motor rotor shaft bearing assembly machine, wherein a flexible pressure plate is provided on the lower surface of the pressure plate, and a guide boss is provided on the central part of the pressure plate.

[0016] The present invention relates to a mid-mounted motor rotor shaft bearing assembly machine, wherein two height adjustment cylinders are provided and are respectively located on both sides of the rotor shaft positioning plate, and the movable end of the height adjustment cylinder faces downward and abuts against the mounting base plate.

[0017] The mid-mounted motor rotor shaft bearing assembly machine of the present invention includes a bearing feeding assembly comprising a three-jaw cylinder, a lifting module for driving the three-jaw cylinder to rise and fall, and a traversing module for driving the lifting module to move laterally.

[0018] A method for assembling a rotor shaft bearing of a mid-drive motor, using the mid-drive motor rotor shaft bearing assembly machine described above, wherein the method includes: S1. The transverse unit moves the bearing positioning seat transversely to the receiving position. The bearing feeding assembly feeds the first bearing to the step position at the upper end of the bearing positioning seat, so that the lower end face of the first bearing abuts against the step position. S2, the inner support cylinder drives the two inner support arms to switch to the first open state. At this time, the end of the partition plate extends out of the second slot and is located at the upper end face of the first bearing. S3. The bearing feeding assembly feeds the second bearing above the first bearing. The inner support cylinder drives the two inner support arms to switch from the first open state to the second open state. At this time, the middle part of the partition plate extends out of the second slot and is embedded between the first bearing and the second bearing. The two bearings are radially tensioned and positioned on the step position by the squeezing action of the partition plate. S4. Manually place a rotor shaft on the positioning fixture of the rotor shaft positioning plate, and manually place a bearing on the upper part of the rotor shaft to form an upper bearing. S5. Drive the height adjustment cylinder to raise the height of the rotor shaft positioning plate so that the pressing part of the pressing plate fits and holds the upper bearing. S6. The bearing positioning seat moves laterally from the receiving position to the pressing position under the drive of the transverse unit; S7. The press drives the pressing plate to move downwards, and the height adjustment cylinder coordinates the movement to control the rotor shaft positioning plate to follow the downward movement. When the second bearing contacts the pressing position inside the rotor shaft, the pressing process begins. S8. After the second bearing is pressed into place, the first bearing has partially entered the corresponding pressing position; the inner support cylinder drives the two inner support arms to switch to the retracted state, releasing the pressure and tension of the partition plate on the two bearings; S9. The press drives the pressing plate to move downwards, completing the pressing of the first bearing and the upper bearing; S10. After pressing is completed, the press drives the pressing plate to move upward and reset, the height adjustment cylinder drives the rotor shaft positioning plate to move upward and reset, the bearing positioning seat moves laterally to exit the pressing position, and the pressed rotor shaft is taken out.

[0019] The beneficial effects of this invention are as follows: 1. High-efficiency three-bearing synchronous / sequential press-fitting: Through the unique bearing positioning seat and internal support structure, the press-fitting of one bearing at the top of the rotor shaft and two bearings inside the shaft can be completed in one go, significantly improving assembly efficiency.

[0020] 2. High coaxiality and good assembly quality: The height adjustment cylinder and precision guide structure ensure that the axes of the upper bearing and the two lower bearings are aligned; the two bearings inside the shaft are radially tensioned and positioned by the partition plate before pressing, which effectively prevents them from deviating during the pressing process, ensuring the final coaxiality of the three bearings and improving the dynamic balance performance and running stability of the rotor assembly.

[0021] 3. Damage-proof design: The rubber partition can separate and position the two bearings before pressing, and play a guiding and buffering role during the pressing process; its built-in stainless steel sheet can provide the necessary support rigidity; the flexible pressure plate protects the bearing end face; these designs minimize the risk of scratching the mating surfaces of the bearings and rotor shaft during the pressing process.

[0022] 4. High degree of automation and simple operation: From bearing loading, positioning, rotor shaft placement to final pressing, the process is clear and highly automated, which reduces the skill requirements for operators and ensures the consistency of product assembly quality. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a front view of the assembly machine for the rotor shaft bearing of the mid-mounted motor according to a preferred embodiment of the present invention; Figure 2This is a schematic diagram of the assembly structure of the mid-mounted motor rotor shaft bearing according to a preferred embodiment of the present invention; Figure 3 This is a structural schematic diagram of the mid-mounted motor rotor shaft bearing assembly machine from another perspective, according to a preferred embodiment of the present invention. Figure 4 yes Figure 1 Enlarged view of point A in the middle; Figure 5 This is a cross-sectional view of the partition plate of the mid-mounted motor rotor shaft bearing assembly machine according to a preferred embodiment of the present invention; Figure 6 This is a rear sectional view of the rotor shaft press-fitted bearing of the rotor shaft bearing assembly machine of the mid-drive motor according to a preferred embodiment of the present invention. Figure 7 This is a flowchart of the assembly method of the rotor shaft bearing of the mid-mounted motor according to a preferred embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0025] Please see Figures 1 to 6 The present invention provides a mid-mounted motor rotor shaft bearing assembly machine, comprising a press bracket 1, a bearing positioning seat 2, a transverse unit 3, a press 4, a press plate 5, a rotor shaft positioning plate 6, a height adjustment cylinder 7, a bearing feeding assembly 8, and an internal support mechanism. The pressing bracket forms the main frame, including a mounting base plate 101, a mounting top plate 102, and four connecting columns 103; the transverse moving unit 3 is set on the mounting base plate 101, and the bearing positioning seat 2 is installed on the sliding part of the transverse moving unit 3, which can move horizontally between the receiving position A and the pressing position B under its drive. The press 4 (such as a servo electric cylinder or pneumatic cylinder) is installed on the mounting top plate 102; the press plate 5 and the rotor shaft positioning plate 6 are slidably fitted on the connecting column 103 through the guide sleeve 104 to achieve precise vertical guidance; the press plate 5 is connected to the output end of the press 4; a height adjustment cylinder 7 is provided on each side of the rotor shaft positioning plate 6, and its piston rod extends downward and the end can abut against the mounting base plate 101, thereby realizing the lifting and height locking of the rotor shaft positioning plate 6; The rotor shaft positioning plate 6 has an opening 61 in the middle and a positioning fixture 62 on the edge of the opening 61; the cylindrical central motor rotor shaft can be placed in the positioning fixture 62, and its axis is aligned with the center of the opening 61; the upper bearing 90 can be pre-placed on the upper end of the rotor shaft. The bearing loading assembly 8 can be installed on one side of the frame, including a three-jaw cylinder 81, a lifting module 82 and a transverse module 83, for grabbing bearings from the hopper and conveying them to the bearing positioning seat 2 located at the receiving position A; The bearing positioning seat 2 is the core component. Its upper end face is provided with a mounting groove 21, and the inner support cylinder 22 is installed in it. The two inner support arms 23 of the inner support cylinder 22 are inverted L-shaped. The mounting groove 21 has a first slot 24 at the opening. The upper outer side of the bearing positioning seat 2 is provided with a step position 25 for supporting two bearings stacked on top of each other. A rubber partition plate 26 is fixed to the outer side of the longitudinal edge of the inner support arm 23. The inner wall of the mounting groove 21 has a second slot 27 that communicates with the step position 25 for the partition plate 26 to extend and retract. The partition piece 26 has a flat and thin end 261, a flat and thick middle section 262, and a transition arc surface 263 at the connection point; a stainless steel sheet 264 can be embedded inside to enhance rigidity; the inner support cylinder 22 can precisely control the inner support arm 23 to be in three states: Retracted state: The inner support arm 23 is fully retracted into the mounting slot 21, and the partition plate 26 is located in the second slot 27, which does not affect the insertion and removal of the bearing; First open state: The lateral edge of the inner support arm 23 enters the first slot 24, and the thin end 261 of the partition piece 26 extends out of the second slot 27 and is located on the upper surface of the first bearing 91. Second open state: The lateral edge of the inner support arm 23 extends out of the first slot 24, and the thick middle part 262 of the partition piece 26 extends out of the second slot 27, inserts between the first bearing 91 and the second bearing 92 and stretches and tensions them radially (the end face of the second bearing 92 is pressed by the lateral edge of the inner support arm 23). A flexible pressure plate 51 can be provided on the lower surface of the pressing plate 5, and a guide boss 52 is provided in the middle to guide the upper bearing during the initial pressing. The assembly method of the present invention is as follows: Loading and positioning: The bearing positioning seat 2 moves to the receiving position A; the loading assembly 8 places the first bearing 91 into the step position 25; the inner support cylinder 22 drives the inner support arm 23 to the first open state, and the end 261 of the thin partition plate is located on the first bearing 91; the loading assembly 8 places the second bearing 92; the inner support cylinder 22 drives the inner support arm 23 to the second open state, and the middle part 262 of the thick partition plate extends out and is squeezed between the two bearings to radially tension and fix them. Rotor shaft placement: Place the rotor shaft 10 into the positioning fixture 62, and place the upper bearing 90 on the upper end of the rotor shaft 10; Alignment: Raise the rotor shaft positioning plate 6 so that the upper bearing 90 contacts and is positioned with the pressure plate 51 of the press plate 5; Feed: The bearing locating seat 2 moves laterally to the press-fit position B, and the two bearings on it are aligned with the assembly position inside the rotor shaft from below; Step-by-step pressing: Press 4 drives pressing plate 5 to press down, and height adjustment cylinder 7 coordinates to control rotor shaft positioning plate 6 to move down; the second bearing 92 is first pressed into the middle position inside the rotor shaft; when it is pressed into place, the first bearing 91 has also partially entered its installation position and completed positioning; at this time, inner support cylinder 22 retracts inner support arm 23 to the retracted state, partition plate 26 retracts, and releases the constraint on the first bearing 91; Pressing complete: Press 4 continues to press down, fully pressing the first bearing 91 into place, and at the same time pressing the upper bearing 90 into place; Reset and remove components: All actuators are reset, and the assembled rotor shaft assembly is removed.

[0026] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A mid-mounted motor rotor shaft bearing assembly machine, characterized in that, The device includes a bearing positioning seat, a lateral movement unit that drives the bearing positioning seat to move laterally, and a pressing bracket; the pressing bracket is provided with a press, a pressing plate, and a rotor shaft positioning plate from top to bottom; the pressing plate and the rotor shaft positioning plate are both longitudinally slidably disposed on the pressing bracket, the pressing plate is driven to move longitudinally by the press, and the rotor shaft positioning plate is provided with a height adjusting cylinder to adjust its height position; The bearing positioning seat has a receiving position and a pressing position in its lateral travel; the central motor rotor shaft bearing assembly machine also includes a bearing feeding assembly for feeding the bearing positioning seat bearing at the receiving position; the rotor shaft positioning plate is provided with an opening for the bearing positioning seat to extend from bottom to top and a positioning fixture for positioning the rotor shaft located at the edge of the opening; the pressing position is located directly below the opening; The bearing positioning seat has an installation groove on its upper surface, and an inner support cylinder is installed in the installation groove. The two inner support arms of the inner support cylinder are both inverted L-shaped. The opening of the installation groove has a first slot for the lateral side of the inner support arm to extend out. The outer surface of the upper end of the bearing positioning seat has a step for accommodating two bearings. The outer surface of the longitudinal side of the inner support arm has a rubber partition for inserting between the two bearings on the step. The inner wall of the installation groove has a second slot for the partition to extend out, and the second slot is connected to the step.

2. The mid-mounted motor rotor shaft bearing assembly machine according to claim 1, characterized in that, The two inner support arms of the inner support cylinder have a retracted state, a first open state, and a second open state. In the retracted state, both inner support arms are retracted into the mounting slots, and the partition plate is located within the second slot; In the first open state, the lateral edges of the two inner support arms enter the first slot, and the end of the partition plate extends out of the second slot; In the second open state, the lateral edges of the two inner support arms extend out of the first slot, and the middle part of the partition plate extends out of the second slot.

3. The mid-mounted motor rotor shaft bearing assembly machine according to claim 2, characterized in that, The ends and the middle of the partition are both flat, and the thickness of the ends of the partition is less than the thickness of the middle of the partition.

4. The mid-mounted motor rotor shaft bearing assembly machine according to claim 3, characterized in that, A transition arc surface is provided at the connection between the end of the partition piece and the middle part of the partition piece.

5. The mid-mounted motor rotor shaft bearing assembly machine according to claim 3, characterized in that, The partition plate has a deformable stainless steel sheet embedded inside.

6. The mid-mounted motor rotor shaft bearing assembly machine according to claim 2, characterized in that, The press-fitting bracket includes a mounting base plate, a mounting top plate, and multiple connecting columns; the connecting columns connect the mounting base plate and the mounting top plate; the press is mounted on the mounting top plate, and the transverse movement unit is mounted on the mounting base plate; both the press-fitting plate and the rotor shaft positioning plate are provided with multiple guide sleeves that cooperate with the connecting columns.

7. The mid-mounted motor rotor shaft bearing assembly machine according to claim 6, characterized in that, The lower surface of the pressing plate is provided with a flexible pressing plate, and the center of the pressing plate is provided with a guide boss.

8. The mid-mounted motor rotor shaft bearing assembly machine according to claim 6, characterized in that, Two height adjustment cylinders are provided and are located on both sides of the rotor shaft positioning plate, with the movable end of the height adjustment cylinder facing downward and abutting against the mounting base plate.

9. The mid-mounted motor rotor shaft bearing assembly machine according to claim 2, characterized in that, The bearing loading assembly includes a three-jaw cylinder, a lifting module that drives the three-jaw cylinder to rise and fall, and a traversing module that drives the lifting module to move laterally.

10. A method for assembling a rotor shaft bearing of a mid-drive motor, using the mid-drive motor rotor shaft bearing assembly machine as described in any one of claims 2-9, characterized in that, The method includes: S1. The transverse unit moves the bearing positioning seat transversely to the receiving position. The bearing feeding assembly feeds the first bearing to the step position at the upper end of the bearing positioning seat, so that the lower end face of the first bearing abuts against the step position. S2, the inner support cylinder drives the two inner support arms to switch to the first open state. At this time, the end of the partition plate extends out of the second slot and is located at the upper end face of the first bearing. S3. The bearing feeding assembly feeds the second bearing above the first bearing. The inner support cylinder drives the two inner support arms to switch from the first open state to the second open state. At this time, the middle part of the partition plate extends out of the second slot and is embedded between the first bearing and the second bearing. The two bearings are radially tensioned and positioned on the step position by the squeezing action of the partition plate. S4. Manually place a rotor shaft on the positioning fixture of the rotor shaft positioning plate, and manually place a bearing on the upper part of the rotor shaft to form an upper bearing. S5. Drive the height adjustment cylinder to raise the height of the rotor shaft positioning plate so that the pressing part of the pressing plate fits and holds the upper bearing. S6. The bearing positioning seat moves laterally from the receiving position to the pressing position under the drive of the transverse unit; S7. The press drives the pressing plate to move downwards, and the height adjustment cylinder coordinates the movement to control the rotor shaft positioning plate to follow the downward movement. When the second bearing contacts the pressing position inside the rotor shaft, the pressing process begins. S8. After the second bearing is pressed into place, the first bearing has partially entered the corresponding pressing position; the inner support cylinder drives the two inner support arms to switch to the retracted state, releasing the pressure and tension of the partition plate on the two bearings; S9. The press drives the pressing plate to move downwards, completing the pressing of the first bearing and the upper bearing; S10. After pressing is completed, the press drives the pressing plate to move upward and reset, the height adjustment cylinder drives the rotor shaft positioning plate to move upward and reset, the bearing positioning seat moves laterally to exit the pressing position, and the pressed rotor shaft is taken out.

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