Bearing gear composite grinding center

Abstract

The application discloses a bearing and gear composite grinding center and belongs to the technical field of precision grinding processing. The grinding center comprises a bed body, a Z-direction transmission mechanism and an X-direction transmission mechanism are arranged on the bed body, a workpiece spindle is arranged on the Z-direction transmission mechanism, the grinding center adopts a horizontal layout, the workpiece spindle moves along the Z-axis direction through the Z-direction transmission mechanism, a first spindle and a second spindle are fixedly arranged on an X-axis sliding plate of the X-direction transmission mechanism, and the position switching of the workpiece spindle and the first spindle or the second spindle is realized through the Z-direction movement of the workpiece spindle. The application realizes the composite machining of bearing channels, gear tooth types and reference surfaces under one-time clamping of a workpiece, can cover the precision grinding of concentric / eccentric structures, internal and external gears, bearing channels, robot reducer integrated components and micro gears, eliminates reference conversion errors, and has the advantages of small inertia, good precision consistency, no need of maintenance of a crown block, low requirement on a foundation and the like.

Description

Technical Field

[0001] This invention belongs to the field of precision grinding, and more specifically, relates to a bearing and gear composite grinding center. Background Technology

[0002] As industrial robots develop towards higher precision, higher rigidity, and lighter weight, key components in robot joint reducers (such as RV reducers, harmonic reducers, and planetary reducers) are showing a significant trend towards integration. Bearing raceways and gear tooth surfaces are often integrated into the same component, or require extremely high coaxiality and relative positional accuracy between the two. For example, the rigid wheel of a harmonic reducer integrates the internal gear ring and the bearing mounting reference surface; the pin gear housing of an RV reducer integrates the internal pin tooth groove and the main bearing positioning hole / end face; and the internal gear ring of a planetary reducer integrates the internal teeth and the internal bearing raceway.

[0003] At the same time, the rapid development of the humanoid robot industry has placed new demands on gears, requiring miniaturization, lightweighting, and high precision: gear modules must be minimized (minimum module can reach 0.05mm), flexible gear walls must be extremely thin (only 0.2-0.8mm), and tooth profile errors must be controlled within 3-5 micrometers. Secondary clamping and alignment of micro gears is extremely difficult, and thin-walled structures are prone to deformation or damage during repeated clamping.

[0004] However, the processing of the above-mentioned parts under the traditional processing mode has the following prominent problems:

[0005] First, the functions are limited, and the equipment investment is large. Gear tooth profile grinding (including spur and helical teeth) relies on gear grinding machines, grinding of reference surfaces such as internal holes, external diameters, and end faces relies on universal grinding machines or internal cylindrical grinding machines, and grinding of bearing raceways relies on bearing-specific grinding machines. To complete the entire machining of an integrated component, multiple machines with different functions are usually required, resulting in a lack of compactness in the production line and increasing equipment investment costs and floor space.

[0006] Secondly, multiple clamping operations lead to datum dispersion, making it difficult to guarantee accuracy. When workpieces move between multiple machines, multiple clamping and repeated tool setting are required, which not only increases the cumulative error of datum installation but also increases the probability of datum surface damage. This is especially true for composite components integrating internal gears and bearings, where the concentricity requirements between the internal gear pitch circle and the bearing rotation center are extremely stringent. In harmonic reducers, this concentricity deviation directly leads to meshing interference between the rigid and flexible gears, determining the reducer's lifespan and load-bearing capacity. In RV reducers, deviations in the pin tooth groove position and bearing bore concentricity cause torque fluctuations. In planetary reducers, eccentricity between the gear ring and bearing raceway leads to uneven meshing of planetary gears, generating noise and increased backlash. Traditional sequential machining methods cannot fundamentally eliminate this error.

[0007] Third, it is difficult to adapt to the trend of gear miniaturization. For micro gears with extremely small module and extremely thin wall thickness, the secondary clamping and alignment itself is a huge source of precision loss, and multiple clamping can easily lead to deformation of thin-walled parts or damage to the reference surface.

[0008] Fourth, existing vertical compound grinding machines have structural technical defects. Most gear compound grinding machines currently on the market adopt a vertical layout, with their Z-axis feed achieved by the grinding wheel spindle moving up and down along the column. This vertical structure has the following inherent defects:

[0009] Large inertia of moving parts: The total mass of the grinding wheel spindle, drive motor and slide plate can reach hundreds of kilograms. The large inertia causes lag in acceleration and deceleration response, making it difficult to achieve high-precision feed control. Moreover, the vibration is obvious when moving up and down at high speed, which limits the further improvement of grinding accuracy.

[0010] The Z-axis motion is affected by gravity: the forces are asymmetrical when moving upwards and downwards, resulting in inconsistent feed accuracy in both directions; and as the grinding wheel spindle extends at different heights, the rigidity of the column changes, making it difficult to maintain consistent accuracy throughout the entire stroke.

[0011] Dual spindle configuration requires two Z-axis: When a machine tool needs to be configured with two grinding wheel spindles, the vertical structure usually requires two independent Z-axis drive systems or a complex spindle changing mechanism. The differences in manufacturing, assembly and thermal deformation between the two Z-axis will introduce dual-axis synchronization error, which will directly affect the machining accuracy.

[0012] Maintenance is difficult and requires high user skills: Core components such as the grinding wheel spindle, Z-axis slide plate, and guide rail slider are all located at a high position on the column (usually 2-4 meters). When repairing, replacing, or adjusting the precision, overhead cranes or large cranes must be used. This not only requires users to have heavy lifting equipment and certified operators, but also results in long equipment maintenance cycles and large downtime losses due to the strict safety requirements and complicated procedures of lifting operations.

[0013] High manufacturing and installation costs: The tall columns and cantilever structure result in complex castings, a large amount of materials, and difficult assembly; the high center of gravity and large cantilever load place extremely strict requirements on the bearing capacity and stability of the foundation, usually requiring deep excavation of the foundation and thick concrete foundation, resulting in high equipment manufacturing and user installation costs.

[0014] For example, patent number CN104889863A discloses a large-scale high-precision gear composite grinding center, which adopts a vertical layout and realizes gear one-time clamping and processing through external gear grinding function module and internal gear grinding function module, and can complete the grinding of tooth surface, inner hole and end face. However, the following shortcomings still exist in this scheme: (1) It adopts a vertical layout, and the Z-axis moving parts are grinding wheel spindle and slide plate. The total mass can reach hundreds of kilograms, the motion inertia is large, the acceleration and deceleration response is lagging, and the force is asymmetrical when the Z-axis moves up and down, and the feed accuracy is inconsistent in the forward and reverse directions; (2) It only targets the tooth profile, inner hole and end face of the gear itself, and does not involve the forming grinding of the bearing ring groove, which cannot meet the processing requirements of the integrated composite component of "gear + bearing" in the robot reducer; (3) It does not set up a swing angle device that can switch between spur and helical gear processing, the processing flexibility is limited, and it cannot adapt to the flexible switching between spur and helical gears; (4) Its dual spindle configuration requires two independent Z-axis drive systems or complex spindle changing mechanisms. The manufacturing, assembly and thermal deformation differences between the two Z-axis will introduce dual-axis synchronization errors.

[0015] Fifth, the work is labor-intensive and inefficient. Operators need to master the operation skills of multiple machines, repeatedly clamping and setting tools between them, which severely restricts production efficiency.

[0016] Currently, there is no composite grinding center on the market that can break down the barriers in the bearing and gear industry, complete precision forming grinding of bearing raceways, generating grinding of gear teeth, and grinding of internal and external cylindrical datums on the same equipment and with the same clamping reference, and adapt to flexible switching between spur and helical teeth as well as machining of eccentric structures. Summary of the Invention

[0017] The main objective of this invention is to provide a bearing and gear composite grinding center, which aims to achieve multi-process composite machining of bearing groove grinding, gear tooth profile grinding and datum surface grinding in a single workpiece clamping by optimizing the machine tool structure. It also achieves flexible switching between spur and helical teeth through a swing angle mechanism, thereby reducing equipment investment, eliminating datum conversion errors, and improving machining efficiency and accuracy.

[0018] To achieve the above objectives, the present invention adopts the following technical solution:

[0019] A bearing and gear composite grinding center includes a bed, on which a Z-axis transmission mechanism and an X-axis transmission mechanism are provided. A workpiece spindle is provided on the Z-axis transmission mechanism. The workpiece spindle is used to clamp and drive the workpiece to rotate. The grinding center is characterized by a horizontal layout. The workpiece spindle moves along the Z-axis direction through the Z-axis transmission mechanism. An X-axis slide is fixedly provided on the X-axis transmission mechanism. A first spindle and a second spindle are provided on the X-axis slide. The first spindle and the second spindle are fixedly provided on the X-axis slide along the Z-axis direction. The position switching between the workpiece spindle and the first spindle or the second spindle is achieved by the Z-axis movement of the workpiece spindle.

[0020] The first spindle is configured as a machining spindle, at least for grinding the mounting reference surface of the workpiece, or for shaping the groove of the bearing ring by mounting a shaping grinding wheel.

[0021] A lifting mechanism that moves up and down along the Y-axis is provided on the X-axis slide plate and on one side of the first spindle. A second spindle is provided on the lifting mechanism. The second spindle is configured as a gear machining spindle and is used to grind the teeth of the gear workpiece.

[0022] The lifting mechanism is also equipped with a swing angle device, and the second spindle can be swing-adjusted through the swing angle device so that the second spindle can be switched to an angle corresponding to straight gear machining or an angle corresponding to helical gear machining.

[0023] The first spindle and the second spindle are configured such that, under one clamping of the workpiece spindle, the first spindle first grinds the mounting reference surface of the workpiece, and then the second spindle grinds the tooth profile of the gear workpiece using the mounting reference surface as the positioning reference.

[0024] As a parallel technical solution, a bearing and gear composite grinding center includes a bed, on which a Z-axis transmission mechanism and an X-axis transmission mechanism are provided. A workpiece spindle is mounted on the Z-axis transmission mechanism, and the workpiece spindle is used to clamp and drive the workpiece to rotate. The grinding center adopts a horizontal layout. The workpiece spindle moves along the Z-axis direction via the Z-axis transmission mechanism. An X-axis slide is fixedly mounted on the X-axis transmission mechanism, and a first spindle and a second spindle are mounted on the X-axis slide. The position switching between the workpiece spindle and the first or second spindle is achieved by the Z-axis movement of the workpiece spindle. The first spindle is configured as a machining spindle. It is used at least for grinding the mounting reference surface of a workpiece, or for grinding the grooves of a bearing ring by mounting a shaped grinding wheel; the X-axis slide plate is also provided with a lifting mechanism and a swing angle device, the second spindle can be raised and lowered along the Y-axis direction by the lifting mechanism, and the second spindle can swing and adjust the angle by the swing angle device to switch between grinding spur teeth or helical teeth; the first spindle and the second spindle are configured such that: under the clamping of the workpiece spindle, the first spindle first grinds the mounting reference surface of the workpiece, and then the second spindle grinds the tooth profile of the gear workpiece with the mounting reference surface as the positioning reference.

[0025] Furthermore, when the second spindle swings to the first angle via the swing angle device, the second spindle is used to grind spur gears; when the second spindle swings to the second angle via the swing angle device, the second spindle is used to grind helical gears.

[0026] Furthermore, the swing angle device includes a swing drive mechanism and a locking mechanism. The swing drive mechanism is used to drive the second spindle to swing to a predetermined angle, and the locking mechanism is used to lock and fix the second spindle after it has swung to the desired position.

[0027] Furthermore, the swing angle device also includes a swing angle body, a swing angle shaft, and a swing angle rotating plate. The swing angle body is fixedly installed on the lifting mechanism. The swing angle body is rotatably connected to the swing angle rotating plate through the swing angle shaft. The second main shaft is fixedly installed on the swing angle rotating plate. The swing drive mechanism is a swing drive motor, which is used to drive the swing angle rotating plate to swing around the swing angle shaft to a predetermined angle.

[0028] Furthermore, an automatic tool magazine is fixedly installed on the machine bed. The automatic tool magazine is located on one side of the X-axis transmission mechanism and is used to automatically change the cutting tools or grinding wheels for the first spindle.

[0029] Furthermore, a first grinding wheel dresser is fixedly installed on the Z-axis transmission mechanism. The first grinding wheel dresser is located on one side of the workpiece spindle and is used to dress the toothed grinding wheel on the second spindle.

[0030] Furthermore, the lifting mechanism includes a lifting platform and a lifting drive device. The lifting platform is connected to the X-axis transmission mechanism through the lifting drive device, and the lifting drive device is used to drive the lifting platform to move up and down along the Y-axis direction.

[0031] Furthermore, a second grinding wheel dresser is fixedly installed on the workpiece spindle. The second grinding wheel dresser is located on the side of the workpiece spindle away from the first grinding wheel dresser and is used to dress the grinding wheel on the first spindle.

[0032] Furthermore, the Z-axis transmission mechanism includes a Z-axis slide plate and a Z-axis drive device. The Z-axis drive device is connected to the Z-axis slide plate to drive the Z-axis slide plate to move back and forth along the Z-axis direction. The workpiece spindle is fixedly mounted on the Z-axis slide plate. The X-axis transmission mechanism includes an X-axis slide plate and an X-axis drive device. The X-axis drive device is connected to the X-axis slide plate to drive the X-axis slide plate to move back and forth along the X-axis direction. Both the first spindle and the second spindle are mounted on the X-axis slide plate.

[0033] Furthermore, both the Z-axis slide plate and the X-axis slide plate are provided with several fixing holes for adjusting the installation position of each spindle.

[0034] Furthermore, the first grinding wheel dresser and / or the second grinding wheel dresser are configured to dress the grinding wheel using a forming dressing mode or a CNC interpolation dressing mode, and the two dressing modes can be switched according to processing requirements.

[0035] Furthermore, the CNC interpolation dressing mode dresses the grinding wheel profile according to the CNC program trajectory by the coordinated movement of the first grinding wheel dresser and / or the second grinding wheel dresser along at least two coordinate axes.

[0036] Furthermore, an external gear grinding wheel is mounted on the second spindle for grinding the tooth profile of the external gear.

[0037] Furthermore, an internal gear grinding wheel is mounted on the second spindle. The second spindle moves into the inner hole of the gear workpiece under the linkage drive of the X-axis transmission mechanism and the Z-axis transmission mechanism to grind the tooth profile of the internal gear.

[0038] Furthermore, a profile grinding wheel is mounted on the first spindle, and the first spindle is configured to perform profile grinding on the inner and outer cylindrical circles of a workpiece, and / or to perform profile grinding on the bearing groove of a bearing workpiece.

[0039] Furthermore, the bearing raceway includes a deep groove ball bearing raceway, an angular contact ball bearing raceway, or a cylindrical roller bearing raceway.

[0040] Furthermore, by replacing the forming grinding wheels of different types or profiles, the first spindle can selectively perform gear inner hole grinding, gear outer circle grinding, bearing inner ring groove grinding, and bearing outer ring groove grinding on the same machine tool.

[0041] Furthermore, the first spindle, through the CNC linkage of the X-axis transmission mechanism and the Z-axis transmission mechanism with the workpiece spindle, performs follow-up grinding on the eccentric hole and / or eccentric outer circle on the workpiece.

[0042] Furthermore, the workpiece is a cycloidal wheel of a cycloidal reducer, the first spindle grinds one or more eccentric holes on the cycloidal wheel, and the second spindle grinds the outer cycloidal tooth profile of the cycloidal wheel.

[0043] Furthermore, the first spindle can be adapted to the machining of cycloidal wheels with different eccentricities by replacing grinding wheels of different specifications or adjusting CNC linkage parameters.

[0044] Furthermore, the grinding center is used to process a composite component integrating an internal gear and a bearing. The composite component integrates at least the internal gear tooth surface and the bearing mounting reference surface. The first spindle processes the bearing mounting reference surface, and the second spindle processes the internal gear tooth surface. Both processes are completed in a single clamping operation of the workpiece spindle to ensure the concentricity between the pitch circle of the internal gear tooth surface and the rotation center of the bearing mounting reference surface.

[0045] Furthermore, the composite component is the rigid wheel of a harmonic reducer, the pin gear housing of an RV reducer, or the internal gear ring of a planetary reducer.

[0046] Furthermore, the grinding center is used to process micro gears with a module of no more than 1 mm. The first spindle processes the mounting reference surface of the micro gear, and the second spindle processes the tooth profile of the micro gear. Both processes are completed in a single clamping operation.

[0047] Furthermore, the micro gear is a thin-walled gear component in the joint reducer of a humanoid robot, and the wall thickness of the thin-walled gear component is no more than 1 mm.

[0048] Furthermore, the Z-axis movement direction of the Z-axis transmission mechanism is perpendicular to the direction of gravity, and the moving parts of the Z-axis transmission mechanism are the workpiece spindle and the clamped workpiece, so as to reduce the Z-axis moment of inertia and eliminate the influence of gravity on the feed accuracy.

[0049] A method for composite grinding of bearings and gears, using the composite grinding center for bearings and gears as described above, is characterized by comprising the following steps:

[0050] S1: Clamp the workpiece onto the workpiece spindle;

[0051] S2: Grind the mounting reference surface of the workpiece through the first spindle to establish the positioning reference for subsequent tooth profile machining;

[0052] S3: The second main shaft is raised or lowered along the Y-axis to the working position using the lifting mechanism;

[0053] S4: The second spindle is swung to a first angle corresponding to straight gear machining or a second angle corresponding to helical gear machining by means of the swing angle device;

[0054] S5: Using the mounting reference surface processed in step S2 as the positioning reference, the second spindle grinds the tooth profile of the workpiece.

[0055] One of the above-described technical solutions of the present invention has at least one of the following advantages or beneficial effects:

[0056] By integrating the first and second spindles onto the same X-axis transmission mechanism, and cooperating with the Z-axis transmission mechanism, the machine tool can sequentially complete multiple processes such as bearing groove forming grinding, datum surface grinding (internal hole, outer circle, end face), and gear tooth profile grinding without changing the workpiece clamping. Especially when the mounting datum is machined first and then used as a reference for machining the tooth profile or bearing groove, the concentricity and positional accuracy between various features can be effectively guaranteed. This "datum-based" machining method is a fundamental approach to solving the precision problem of miniaturized gears from the perspective of machining principles.

[0057] Flexible switching between spur and helical gear machining: By setting a swing angle device on the lifting mechanism, the second spindle can swing flexibly to different angles, realizing the switching between spur and helical gear grinding without changing equipment or adding an additional indexing mechanism, which greatly expands the processing range and flexibility of the machine tool and adapts to the needs of multi-variety, small-batch gear production.

[0058] High degree of automation: By setting up an automatic tool magazine, the first spindle can automatically change different types of tools or grinding wheels according to processing needs, thereby realizing flexible switching of multiple processes such as internal hole grinding, external cylindrical grinding, end face grinding, and bearing groove forming grinding, further expanding the machine tool's composite processing capabilities.

[0059] Good grinding accuracy retention: By setting the first grinding wheel dresser and the second grinding wheel dresser, the gear grinding wheel and other grinding wheels are dressed independently respectively. The dresser is compatible with both profile dressing and CNC interpolation dressing modes. The most suitable dressing method can be flexibly selected according to different gear types and batches to ensure that the grinding wheel is always in the best working condition and to ensure grinding quality and processing stability.

[0060] Compact structure and space saving: Integrating bearing processing, gear processing and reference processing into one machine significantly reduces the equipment footprint and production line length, thereby reducing the company's factory and operating costs.

[0061] Especially suited to the trend of gear and bearing integration in the robotics industry: For composite components that integrate internal gears and bearings, such as the rigid wheel of harmonic reducer, the pin tooth housing of RV reducer, and the internal gear ring of planetary reducer, this invention, through a process logic of one-time clamping and unified reference, physically ensures the coaxiality of the pitch circle of the internal gear and the rotation center of the bearing, providing core process equipment support for breaking the foreign monopoly in domestic high-precision robot reducers.

[0062] Especially suitable for the trend of miniaturization of gears in humanoid robots: For micro gears with extremely small module and extremely thin wall thickness, this invention avoids the difficulty of alignment and deformation risk caused by secondary clamping, and is a precision manufacturing infrastructure for the humanoid robot industry.

[0063] The horizontal layout offers significant technical and economic advantages: Technically, the workpiece spindle moves along the Z-axis, with the only moving parts being the workpiece spindle and the clamped workpiece, resulting in low inertia and fast dynamic response; the Z-axis movement direction is perpendicular to gravity, ensuring consistent feed accuracy in both directions, unaffected by gravity; both spindles (first and second) are fixed on the same X-axis slide plate, sharing the same Z-axis transmission mechanism, eliminating the need for two sets of Z-axis synchronization and fundamentally eliminating dual-axis synchronization errors. Economically, the horizontal bed structure is regular, castings are simple, and less material is used; the guide rails and drive system do not need to bear large cantilever loads, allowing for smaller specifications and lower motor torque requirements; the machine has a low center of gravity, easy geometric accuracy adjustment, and a short installation and commissioning cycle; and low foundation requirements allow for installation on standard factory floors without deep foundation excavation.

[0064] Easy maintenance and user-friendly design: All core components (first spindle, second spindle, X-axis transmission mechanism, lifting mechanism, etc.) are located near the machine bed at ground level, allowing operators to perform daily inspections, lubrication, precision adjustments, and component replacements without needing to climb. When it is necessary to disassemble components such as the spindle, lead screw, or guide rail slider, a regular forklift can be used for auxiliary lifting, completely eliminating the need for overhead cranes or large lifting equipment. This feature significantly lowers the technical threshold for equipment maintenance, shortens downtime, and makes the composite grinding center of this invention highly user-friendly and marketable, especially suitable for small and medium-sized manufacturing enterprises that lack heavy-duty lifting capabilities. Attached Figure Description

[0065] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0066] Figure 1 This is a schematic diagram of the structure of the bearing and gear composite grinding center in some embodiments of the present invention;

[0067] Figure 2 This is a schematic diagram of the structure of the bearing and gear composite grinding center in some embodiments of the present invention;

[0068] Figure 3 This is a schematic diagram of the structure of the second spindle swinging to the straight gear machining position in some embodiments of the present invention;

[0069] Figure 4 This is a schematic diagram of the structure of the second spindle swinging to the helical gear machining position in some embodiments of the present invention;

[0070] Figure 5 This is a top view schematic diagram of the horizontal layout of the bearing and gear composite grinding center in some embodiments of the present invention. Detailed Implementation

[0071] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0072] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are 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 limiting this invention.

[0073] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0074] 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. Therefore, a feature defined as "first" and "second" may explicitly or implicitly include one or more features.

[0075] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection or a connection that allows communication between the two components; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components, an indirect connection, or an interaction between two components.

[0076] The following disclosure provides many different implementations or examples for different ways of implementing the present invention.

[0077] Reference Figures 1 to 5 As shown, a bearing and gear composite grinding center is provided, including a bed 1, on which a Z-axis transmission mechanism 2 and an X-axis transmission mechanism 3 are provided.

[0078] The bearing and gear composite grinding center of this invention adopts a horizontal layout. The workpiece spindle 4 moves along the Z-axis via the Z-axis transmission mechanism 2. Unlike the structure of existing vertical machine tools where the grinding wheel spindle moves up and down along the Z-axis, the Z-axis moving parts of this invention are only the workpiece spindle 4 and the clamped workpiece. It has low inertia, fast dynamic response, and the direction of movement is perpendicular to the direction of gravity, with consistent feed accuracy in both forward and reverse directions.

[0079] Meanwhile, both the first spindle 7 and the second spindle 8 are fixedly mounted on the X-axis slide plate 31, sharing the same Z-axis transmission mechanism 2. When a process needs to be switched, the workpiece spindle 4 moves along the Z-axis to the corresponding station and is sequentially aligned with the first spindle 7 or the second spindle 8 for processing. This horizontal layout of "workpiece moving, spindle fixed" eliminates the need for each spindle to have an independent Z-axis drive system, fundamentally eliminating dual-axis synchronization errors and ensuring consistent reference.

[0080] Compared to the vertical gear compound grinding center represented by patent number CN104889863A, the horizontal layout of this application differs fundamentally in its kinematic structure. In patent number CN104889863A, the Z-axis feed is achieved by the grinding wheel spindle moving up and down along the column. The moving parts are the grinding wheel spindle, drive motor, and slide plate assembly, resulting in high inertia and significant influence from gravity. In contrast, the Z-axis moving parts of this application are only the workpiece spindle 4 and the clamped workpiece, exhibiting low inertia, fast dynamic response, and a movement direction perpendicular to the direction of gravity, ensuring consistent feed accuracy in both forward and reverse directions. Furthermore, the dual-spindle module of patent number CN104889863A requires independent Z-axis drives or complex switching mechanisms, leading to dual-axis synchronization errors. In contrast, the first spindle 7 and the second spindle 8 of this application are both fixedly mounted on the same X-axis slide plate 31, sharing the same Z-axis transmission mechanism 2, fundamentally eliminating dual-axis synchronization errors. Regarding the processing objects, patent number CN104889863A only targets the tooth profile, inner hole and end face processing of the gear workpiece itself, and does not involve the forming grinding of the bearing ring groove; while the first spindle 7 of this application can perform forming grinding processing on the bearing ring groove by installing a forming grinding wheel, realizing cross-domain integration of the two technical fields of bearing processing and gear processing.

[0081] In terms of equipment maintenance, the horizontal layout of this invention offers significant advantages. All major components (first spindle 7, second spindle 8, X-axis transmission mechanism 3, lifting mechanism, etc.) are arranged at a height near the ground above the machine bed 1, allowing operators to perform routine inspections, lubrication, precision adjustments, and component replacements without needing to climb. When heavier components such as spindles, lead screws, or guide rail sliders need to be disassembled, a forklift can assist in the lifting, completely eliminating the need for overhead cranes or large lifting equipment. Taking the maintenance of the swing angle device of the second spindle 8 as an example, maintenance personnel only need to stand beside the machine tool and use ordinary tools to remove the second spindle 8 along with the swing angle rotating plate from the lifting mechanism, without the need for a crane. This feature significantly lowers the technical threshold for equipment maintenance, shortens maintenance downtime, and greatly reduces the user's daily maintenance costs.

[0082] Compared to vertical compound grinding machines, the horizontal layout of this invention also has a significant cost advantage. Vertical machine tools, due to their tall column structure and cantilever load, have complex castings, thick walls, and high material consumption. They also require extremely high rigidity and precision of the column guideways, and the matching servo motors need to have brakes and high torque specifications. In contrast, this invention adopts a horizontal layout, with a planar and regular structure for the bed 1. The casting process is simple, material is saved, and the specifications of the guideways and motors can be reduced. In terms of installation, the horizontal machine tool has a low center of gravity, and geometric accuracy adjustment is intuitive and simple, significantly shortening the assembly cycle. It also has no special requirements for the factory foundation, eliminating the need for deep foundation excavation, thus reducing the user's factory investment and installation time. These cost advantages give this invention a stronger market competitiveness in industrialization.

[0083] The Z-axis transmission mechanism 2 is equipped with a workpiece spindle 4, which is used to clamp and drive the workpiece to rotate. The Z-axis transmission mechanism 2 includes a Z-axis slide plate 23 and a Z-axis drive device. The Z-axis drive device is connected to the Z-axis slide plate 23 to drive the Z-axis slide plate 23 to move back and forth along the Z-axis direction. The workpiece spindle 4 is fixedly mounted on the Z-axis slide plate 23.

[0084] The X-axis transmission mechanism 3 is equipped with a first spindle 7. The first spindle 7 is configured as a machining spindle, and its end can be fitted with different types of grinding wheels or cutting tools according to machining needs. The first spindle 7 can be used for:

[0085] Install an internal grinding wheel to grind the inner hole of the gear workpiece and establish a positioning reference for subsequent tooth profile machining;

[0086] Install an external cylindrical grinding wheel to grind the outer diameter of the workpiece;

[0087] Install a face grinding wheel to grind the end face of the workpiece;

[0088] Install bearing raceway forming grinding wheels to perform forming grinding on the raceways of bearing rings (such as deep groove ball bearing raceways, angular contact ball bearing raceways, or cylindrical roller bearing raceways).

[0089] Through the CNC linkage of the X-axis transmission mechanism 3, the Z-axis transmission mechanism 2 and the workpiece spindle 4 (C-axis), the eccentric hole and / or eccentric outer circle on the workpiece are subjected to follow-up grinding.

[0090] Internal grinding is a critical process in gear manufacturing. The dimensional accuracy and surface quality of the internal bore directly affect the fit accuracy between the gear and the shaft, as well as the meshing performance of the gear pair. When the first spindle 7 is equipped with an internal grinding wheel for internal grinding, since the internal bore serves as the positioning reference for subsequent tooth profile machining, machining the internal bore first and then the tooth profile ensures the concentricity between the internal bore and the tooth profile. This is a core element in ensuring gear accuracy.

[0091] A lifting mechanism that moves up and down along the Y-axis is provided on one side of the first main shaft 7. The lifting mechanism is mounted on the X-axis transmission mechanism 3. Specifically, the lifting mechanism includes a lifting platform and a lifting drive device. The lifting platform is connected to the X-axis transmission mechanism 3 via the lifting drive device, which drives the lifting platform to move up and down along the Y-axis. Preferably, the lifting drive device uses a ball screw pair driven by a servo motor to achieve high-precision lifting control.

[0092] The lifting mechanism is equipped with a second spindle 8. The second spindle 8 is configured as a gear machining spindle, and its end can be fitted with a gear grinding wheel (such as a worm wheel, profile wheel, external gear grinding wheel, or internal gear grinding wheel) for grinding the gear teeth. Gear grinding is a core process in gear machining that determines the gear's precision grade, directly affecting the gear's transmission accuracy, noise, and lifespan.

[0093] When an external gear grinding wheel is mounted on the second spindle 8, it is used to grind the tooth profile of the external gear. When an internal gear grinding wheel is mounted on the second spindle 8, the second spindle 8 moves into the inner hole of the gear workpiece under the linkage drive of the X-axis transmission mechanism 3 and the Z-axis transmission mechanism 2, and is used to grind the tooth profile of the internal gear. When grinding the internal gear, the lifting mechanism drives the second spindle 8 to adjust its height along the Y-axis, so that the internal gear grinding wheel is aligned with the inner tooth surface of the gear workpiece.

[0094] The lifting mechanism is also equipped with a swing angle device. The second spindle 8 can swing and adjust its angle via the swing angle device. Specifically, the swing angle device includes a swing drive mechanism and a locking mechanism. The swing drive mechanism is used to drive the second spindle 8 to swing to a predetermined angle, and the locking mechanism is used to lock and fix the second spindle 8 after swinging to the desired position, ensuring that the angle remains stable during processing. As a specific embodiment of the present invention, the swing angle device also includes a swing angle body, a swing angle shaft, and a swing angle rotating plate. The swing angle body is fixedly installed on the lifting mechanism, and the swing angle body is rotatably connected to the swing angle rotating plate via the swing angle shaft. The second spindle 8 is fixedly mounted on the swing angle rotating plate. The swing drive mechanism is a swing drive motor (such as a servo motor), which is connected to the swing angle shaft and is used to drive the swing angle rotating plate to swing around the swing angle shaft to a predetermined angle. The locking mechanism is a hydraulic locking or pneumatic locking device.

[0095] When the second spindle 8 swings to a first angle (usually 0°, i.e., the axis of the second spindle 8 is parallel to the axis of the workpiece spindle 4) via the swing angle device, the second spindle 8 is used to grind spur gears. At this time, the grinding wheel performs plunge grinding or generating grinding along the tooth direction of the gear.

[0096] When the second spindle 8 swings to a second angle via the swing angle device (this angle is equal to the helix angle of the gear, and is a non-zero angle, such as 15°, 20°, 30°, etc., depending on the design parameters of the helical gear being machined), the second spindle 8 is used to grind the helical gear. At this time, the grinding direction of the grinding wheel forms a certain angle with the gear axis, thereby grinding a tooth profile with a helix angle on the workpiece.

[0097] With the aforementioned tilt angle adjustment, the present invention can achieve flexible switching between spur and helical gear machining on the same machine tool without replacing equipment or adding an additional indexing mechanism, greatly improving the adaptability and machining range of the machine tool.

[0098] In addition, the second spindle 8 can be raised and lowered along the Y-axis via the lifting mechanism, enabling the second spindle 8 to adapt to gear workpieces of different diameters and quickly switch to the gear machining position after the benchmark machining is completed, without disassembling the workpiece.

[0099] In this embodiment, the X-axis transmission mechanism 3 includes an X-axis slide plate 31 and an X-axis drive device. The X-axis drive device is connected to the X-axis slide plate 31 to drive the X-axis slide plate 31 to move back and forth along the X-axis direction. The first spindle 7, the lifting mechanism, and the second spindle 8 are all mounted on the X-axis slide plate 31. Both the Z-axis slide plate 23 and the X-axis slide plate 31 have several fixing holes 10 for adjusting the installation position of each spindle, allowing the machine tool to quickly adjust the spindle layout according to the processing requirements of different workpieces.

[0100] As a further preferred embodiment, an automatic tool magazine 9 is fixedly installed on the bed 1. The automatic tool magazine 9 is located on one side of the X-axis transmission mechanism 3 and is used to automatically change tools or grinding wheels for the first spindle 7. Through the automatic tool magazine 9, the machine tool can automatically switch between different grinding wheels or tools according to the process requirements, realizing flexible conversion of various processes such as internal hole grinding, external cylindrical grinding, end face grinding, and bearing groove forming grinding, reducing manual intervention and auxiliary time, and improving the degree of automation and processing continuity.

[0101] As a further preferred embodiment, a first grinding wheel dresser 6 is fixedly mounted on the Z-axis transmission mechanism 2. The first grinding wheel dresser 6 is located on one side of the workpiece spindle 4 and is used to dress the toothed grinding wheel on the second spindle 8. The Z-axis transmission mechanism 2 has a mounting groove 21, and a mounting plate 22 is mounted on the mounting groove 21. The first grinding wheel dresser 6 is fixedly mounted on the mounting plate 22. The mounting groove 21 has several positioning holes 211, and the mounting plate 22 has limiting holes 221 that mate with the positioning holes 211. The engagement of the positioning holes 211 and the limiting holes 221 fixes the mounting plate 22 in place, ensuring the stability of the first grinding wheel dresser 6 during operation. Simultaneously, the position of the mounting plate 22 on the mounting groove 21 can be adjusted according to actual conditions to change the position of the first grinding wheel dresser 6 and adapt to the dressing requirements of grinding wheels of different specifications.

[0102] As a further preferred embodiment, a second grinding wheel dresser 5 is fixedly installed on the workpiece spindle 4. The second grinding wheel dresser 5 is located on the side of the workpiece spindle 4 away from the first grinding wheel dresser 6, and is used to dress the grinding wheel on the first spindle 7.

[0103] The first grinding wheel dresser 6 and / or the second grinding wheel dresser 5 are configured to dress the grinding wheel using either a profile dressing mode or a CNC interpolation dressing mode. These two modes can be switched according to processing requirements. The profile dressing mode is suitable for mass production, offering high efficiency and good consistency. The CNC interpolation dressing mode, through the coordinated movement of the grinding wheel dresser along at least two coordinate axes, dresses the grinding wheel profile according to a CNC program trajectory, making it suitable for processing multiple varieties in small batches with complex tooth profiles, offering high flexibility. This compatible configuration of the two dressing modes allows the grinding center of this invention to flexibly select the most suitable dressing method based on different gear types and batches, further improving the adaptability and processing efficiency of the equipment.

[0104] By setting up a first grinding wheel dresser 6 and a second grinding wheel dresser 5 to form a dual dresser structure, the tooth grinding wheel and other grinding wheels can be dressed independently, ensuring that each grinding wheel is always in the best working condition, and ensuring grinding quality and processing stability.

[0105] Example 1: Gear workpiece machining

[0106] When the bearing and gear composite grinding center of the first embodiment of the present invention is working, the gear workpiece is clamped on the workpiece spindle 4.

[0107] First, a reference machining process is performed: As needed, the first spindle 7 is equipped with a corresponding grinding wheel or tool (e.g., an internal grinding wheel). Under the linkage of the X-axis transmission mechanism 3 and the Z-axis transmission mechanism 2, the first spindle 7 performs reference grinding on the gear workpiece—for example, when an internal grinding wheel is installed, the inner hole of the gear workpiece can be ground to establish a positioning reference for subsequent gear machining. During the machining process, the second grinding wheel dresser 5 can dress the grinding wheel on the first spindle 7 as needed.

[0108] After the baseline machining is completed, the first spindle 7 retracts to the safe position. If it is necessary to change to a different specification or type of grinding wheel, the automatic tool magazine 9 automatically completes the tool change operation.

[0109] The gear grinding process then proceeds: the second spindle 8, driven by the lifting mechanism, rises and falls along the Y-axis to the working position. Depending on the gear type, the second spindle 8 is swung to the corresponding angle via the swing angle device—to the first angle (0°) for spur gears and to the second angle (equal to the helix angle) for helical gears. After swivel to the desired position, the locking mechanism locks the swing angle rotating plate in place. Under the linkage of the X-axis transmission mechanism 3 and the Z-axis transmission mechanism 2, the second spindle 8 grinds the gear teeth. During the process, the first grinding wheel dresser 6 can dress the gear grinding wheel on the second spindle 8 as needed. Depending on the type of grinding wheel installed, the gear teeth of external or internal gears can be ground.

[0110] Example 2: Machining of bearing ring grooves

[0111] In one embodiment of the present invention, a bearing groove forming grinding wheel is installed at the end of the first spindle 7. When it is necessary to process the bearing ring, the bearing workpiece is clamped on the workpiece spindle 4. First, the first spindle 7 grinds the mounting reference surface (such as the outer circle or end face) of the bearing workpiece; after the reference machining is completed, without removing the workpiece, the bearing groove forming grinding wheel is replaced by the automatic tool magazine 9, and the first spindle 7 performs forming grinding on the inner or outer ring groove of the bearing workpiece under the linkage of the X and Z axis transmission mechanisms. Since the reference machining and the groove machining are completed in one clamping, the form and position tolerances (such as concentricity and perpendicularity) between the bearing groove and the mounting reference surface are guaranteed. The types of bearings that can be machined include, but are not limited to, deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, and tapered roller bearings.

[0112] Example 3: Machining of the eccentric hole of the cycloidal wheel

[0113] In one embodiment of the invention, the grinding center is used to process the cycloidal wheel of a cycloidal reducer. When processing the eccentric hole on the cycloidal wheel, the workpiece spindle 4 (C-axis) drives the cycloidal wheel to rotate at a constant speed, and the X-axis transmission mechanism 3 drives the first spindle 7 to perform periodic reciprocating motion along the X-axis direction corresponding to the eccentricity, so that the grinding wheel always maintains constant grinding contact with the inner wall of the eccentric hole (i.e., follow-up tracking grinding, also known as tangent point tracking technology). By adjusting the amplitude of the X-axis reciprocating motion, it can adapt to the processing of cycloidal wheels with different eccentricities without changing the eccentric fixture. After the eccentric hole is ground, the workpiece is not removed, and the second spindle 8 grinds the outer cycloidal tooth profile of the cycloidal wheel. Since the eccentric hole and the outer cycloidal teeth share the same clamping datum, the phase error introduced by multiple clamping is completely eliminated.

[0114] Example 4: Machining of an integrated composite component of gears and bearings in a robot reducer

[0115] In one embodiment of the present invention, the grinding center is used to process a composite component integrating an internal gear and a bearing, the composite component integrating at least the internal gear tooth surface and the bearing mounting reference surface. Specifically:

[0116] When machining the rigid wheel of the harmonic reducer, the first spindle 7 machines the bearing mounting reference surface (inner hole, end face, etc.) of the rigid wheel, while the second spindle 8 grinds the internal teeth of the rigid wheel after adjusting the angle through the tilting device. Both processes are completed in a single clamping operation of the workpiece spindle 4, ensuring the concentricity between the pitch circle of the rigid wheel's internal teeth and the rotation center of the bearing mounting reference surface.

[0117] When machining the pin tooth housing of the RV reducer, the first spindle 7 machines the main bearing positioning hole / end face of the pin tooth housing, and the second spindle 8 machines the inner pin tooth groove of the pin tooth housing. Both are completed in one clamping operation of the workpiece spindle 4, ensuring the concentricity of the pin tooth groove position with the bearing hole.

[0118] When machining the internal gear ring of the planetary reducer, the first spindle 7 machines the inner bearing raceway of the internal gear ring, while the second spindle 8 machines the internal gears of the internal gear ring. Both processes are completed in a single clamping operation on the workpiece spindle 4, ensuring the concentricity of the gear ring and the bearing raceway.

[0119] In the aforementioned application scenarios, since the first spindle 7 and the second spindle 8 establish machining references based on the rotation axis of the same workpiece spindle 4, the bearing mounting reference surface and the pitch circle of the internal gear tooth surface remain physically coaxial in a single clamping operation. This "physical-level" precision assurance is unmatched by traditional "coordinate-level" methods (relying on manual or instrumental alignment).

[0120] Example 5: Micro Gear Machining

[0121] In one embodiment of the invention, the grinding center is used to process micro gears with a module of no more than 1 mm, particularly thin-walled gear components (wall thickness no more than 1 mm) in humanoid robot joint reducers. After the micro gear workpiece is clamped on the workpiece spindle 4, the first spindle 7 processes the mounting reference surface of the micro gear, and the second spindle 8 processes the tooth profile of the micro gear; both processes are completed in a single clamping operation. By avoiding secondary clamping, the difficulty of aligning the micro gear and the risk of thin-wall deformation are effectively eliminated.

[0122] Throughout the entire machining process, the workpiece only needs to be clamped once to complete multiple composite machining operations. It can flexibly switch between spur gears and helical gears, and can cover the machining of various geometric features such as concentric holes / outer circles, eccentric holes / eccentric outer circles, external gears, internal gears, and bearing grooves. There is no need to change equipment or re-clamp, which significantly improves machining accuracy and efficiency.

[0123] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions without departing from the concept of the present invention are all within the protection scope of the present invention.

Claims

1. A bearing and gear composite grinding center, characterized in that, The grinding center includes a bed (1), on which a Z-axis transmission mechanism (2) and an X-axis transmission mechanism (3) are provided. A workpiece spindle (4) is provided on the Z-axis transmission mechanism (2). The workpiece spindle (4) is used to clamp and drive the workpiece to rotate. The grinding center adopts a horizontal layout. The workpiece spindle (4) moves along the Z-axis direction through the Z-axis transmission mechanism (2). An X-axis slide plate (31) is fixedly provided on the X-axis transmission mechanism (3). A first spindle (7) and a second spindle (8) are provided on the X-axis slide plate (31). The first spindle (7) and the second spindle (8) are fixedly provided on the X-axis slide plate (31) along the Z-axis direction. The position switching with the first spindle (7) or the second spindle (8) is realized by the Z-axis movement of the workpiece spindle (4). The first spindle (7) is configured as a machining spindle, at least for grinding the mounting reference surface of the workpiece, or for shaping grinding the groove of the bearing ring by mounting a shaping grinding wheel; A lifting mechanism that moves up and down along the Y-axis is provided on the X-axis slide plate (31) and on one side of the first spindle (7). A second spindle (8) is provided on the lifting mechanism. The second spindle (8) is configured as a gear machining spindle for grinding the gear teeth of the gear workpiece. The lifting mechanism is also equipped with a swing angle device. The second spindle (8) can be swing-adjusted by the swing angle device so that the second spindle (8) can be switched to an angle corresponding to straight gear machining or an angle corresponding to helical gear machining. The first spindle (7) and the second spindle (8) are configured such that, under the clamping of the workpiece spindle (4), the first spindle (7) first grinds the mounting reference surface of the workpiece, and then the second spindle (8) grinds the tooth profile of the gear workpiece with the mounting reference surface as the positioning reference.

2. The bearing and gear composite grinding center according to claim 1, characterized in that, When the second spindle (8) swings to the first angle through the swing angle device, the second spindle (8) is used to grind spur gears; when the second spindle (8) swings to the second angle through the swing angle device, the second spindle (8) is used to grind helical gears.

3. The bearing and gear composite grinding center according to claim 1, characterized in that, The swing angle device includes a swing drive mechanism and a locking mechanism. The swing drive mechanism is used to drive the second main shaft (8) to swing to a predetermined angle, and the locking mechanism is used to lock and fix the second main shaft (8) after it swings to the desired position.

4. The bearing and gear composite grinding center according to claim 3, characterized in that, The swing angle device further includes a swing angle body, a swing angle shaft and a swing angle rotating plate. The swing angle body is fixedly installed on the lifting mechanism. The swing angle body is rotatably connected to the swing angle rotating plate through the swing angle shaft. The second main shaft (8) is fixedly installed on the swing angle rotating plate. The swing drive mechanism is a swing drive motor, which is used to drive the swing angle rotating plate to swing around the swing angle shaft to a predetermined angle.

5. A bearing and gear compound grinding center, comprising a bed (1), wherein a Z-axis transmission mechanism (2) and an X-axis transmission mechanism (3) are provided on the bed (1), and a workpiece spindle (4) is provided on the Z-axis transmission mechanism (2), wherein the workpiece spindle (4) is used to clamp and drive the workpiece to rotate, characterized in that, The grinding center adopts a horizontal layout. The workpiece spindle (4) moves along the Z-axis direction through the Z-axis transmission mechanism (2). An X-axis slide plate (31) is fixedly installed on the X-axis transmission mechanism (3). A first spindle (7) and a second spindle (8) are installed on the X-axis slide plate (31). The position switching between the workpiece spindle (4) and the first spindle (7) or the second spindle (8) is realized by the Z-axis movement of the workpiece spindle (4). The first spindle (7) is configured as a machining spindle, at least for grinding the mounting reference surface of the workpiece, or for shaping grinding the groove of the bearing ring by mounting a shaping grinding wheel; The X-axis slide plate (31) is also provided with a lifting mechanism and a swing angle device. The second main shaft (8) can be lifted and lowered along the Y-axis direction through the lifting mechanism, and the second main shaft (8) can swing and adjust the angle through the swing angle device to switch between grinding straight teeth or helical teeth. The first spindle (7) and the second spindle (8) are configured such that, under the clamping of the workpiece spindle (4), the first spindle (7) first grinds the mounting reference surface of the workpiece, and then the second spindle (8) grinds the tooth profile of the gear workpiece with the mounting reference surface as the positioning reference.

6. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, An automatic tool magazine (9) is fixedly installed on the bed (1). The automatic tool magazine (9) is located on one side of the X-axis transmission mechanism (3) and is used to automatically change the cutting tools or grinding wheels for the first spindle (7).

7. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, A first grinding wheel dresser (6) is fixedly installed on the Z-axis transmission mechanism (2). The first grinding wheel dresser (6) is located on one side of the workpiece spindle (4) and is used to dress the toothed grinding wheel on the second spindle (8).

8. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The lifting mechanism includes a lifting platform and a lifting drive device. The lifting platform is connected to the X-axis transmission mechanism (3) through the lifting drive device. The lifting drive device is used to drive the lifting platform to move up and down along the Y-axis.

9. The bearing and gear composite grinding center according to claim 7, characterized in that, A second grinding wheel dresser (5) is fixedly installed on the workpiece spindle (4). The second grinding wheel dresser (5) is located on the side of the workpiece spindle (4) away from the first grinding wheel dresser (6) and is used to dress the grinding wheel on the first spindle (7).

10. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The Z-axis transmission mechanism (2) includes a Z-axis slide plate (23) and a Z-axis drive device. The Z-axis drive device is connected to the Z-axis slide plate (23) to drive the Z-axis slide plate (23) to move back and forth along the Z-axis direction. The workpiece spindle (4) is fixedly mounted on the Z-axis slide plate (23). The X-axis transmission mechanism (3) includes an X-axis slide plate (31) and an X-axis drive device. The X-axis drive device is connected to the X-axis slide plate (31) to drive the X-axis slide plate (31) to move back and forth along the X-axis direction. The first spindle (7) and the second spindle (8) are both mounted on the X-axis slide plate (31).

11. The bearing and gear composite grinding center according to claim 10, characterized in that, Both the Z-axis slide plate (23) and the X-axis slide plate (31) are provided with several fixing holes (10) for adjusting the installation position of each spindle.

12. The bearing and gear composite grinding center according to claim 7, characterized in that, The first grinding wheel dresser (6) and / or the second grinding wheel dresser (5) are configured to dress the grinding wheel using either a forming dressing mode or a CNC interpolation dressing mode, and the two dressing modes can be switched according to processing requirements.

13. The bearing and gear composite grinding center according to claim 12, characterized in that, The CNC interpolation dressing mode uses the first grinding wheel dresser (6) and / or the second grinding wheel dresser (5) to move along at least two coordinate axes in a coordinated manner, and dresses the grinding wheel profile according to the CNC program trajectory.

14. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The second spindle (8) is equipped with an external gear grinding wheel for grinding the tooth profile of the external gear.

15. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, An internal gear grinding wheel is mounted on the second spindle (8). The second spindle (8) moves into the inner hole of the gear workpiece under the linkage drive of the X-axis transmission mechanism (3) and the Z-axis transmission mechanism (2) to grind the tooth profile of the internal gear.

16. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The first spindle (7) is equipped with a profile grinding wheel. The first spindle (7) is configured to perform profile grinding on the inner and outer cylindrical circles of the workpiece and / or on the bearing groove of the bearing workpiece.

17. The bearing and gear composite grinding center according to claim 16, characterized in that, The bearing raceway includes deep groove ball bearing raceway, angular contact ball bearing raceway, or cylindrical roller bearing raceway.

18. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The first spindle (7) can perform gear inner hole grinding, gear outer circle grinding, bearing inner ring groove grinding and bearing outer ring groove grinding on the same machine tool by changing different types or contours of forming grinding wheels.

19. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The first spindle (7) performs follow-up grinding of the eccentric hole and / or eccentric outer circle on the workpiece through the CNC linkage of the X-axis transmission mechanism (3) and the Z-axis transmission mechanism (2) with the workpiece spindle (4).

20. The bearing and gear composite grinding center according to claim 19, characterized in that, The workpiece is a cycloidal wheel of a cycloidal reducer. The first spindle (7) grinds one or more eccentric holes on the cycloidal wheel, and the second spindle (8) grinds the outer cycloidal tooth profile of the cycloidal wheel.

21. The bearing and gear composite grinding center according to claim 20, characterized in that, The first spindle (7) can adapt to the processing of cycloidal wheels with different eccentricities by changing grinding wheels of different specifications or adjusting CNC linkage parameters.

22. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The grinding center is used to process a composite component integrating an internal gear and a bearing. The composite component integrates at least the internal gear tooth surface and the bearing mounting reference surface. The first spindle (7) processes the bearing mounting reference surface, and the second spindle (8) processes the internal gear tooth surface. Both are completed in one clamping operation on the workpiece spindle (4) to ensure the concentricity between the pitch circle of the internal gear tooth surface and the rotation center of the bearing mounting reference surface.

23. The bearing and gear composite grinding center according to claim 22, characterized in that, The composite component is the rigid wheel of a harmonic reducer, the needle gear housing of an RV reducer, or the internal gear ring of a planetary reducer.

24. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The grinding center is used to process micro gears with a module of no more than 1 mm. The first spindle (7) processes the mounting reference surface of the micro gear, and the second spindle (8) processes the tooth profile of the micro gear. Both are completed in one clamping.

25. The bearing and gear composite grinding center according to claim 24, characterized in that, The micro gear is a thin-walled gear component in the joint reducer of a humanoid robot, and the wall thickness of the thin-walled gear component is no more than 1 mm.

26. The bearing and gear composite grinding center according to any one of claims 1 to 5, characterized in that, The Z-axis motion direction of the Z-axis transmission mechanism (2) is perpendicular to the direction of gravity. The moving parts of the Z-axis transmission mechanism (2) are the workpiece spindle (4) and the workpiece being clamped, so as to reduce the Z-axis motion inertia and eliminate the influence of gravity on the feed accuracy.

27. A method for composite grinding of bearings and gears, using a composite grinding center for bearings and gears as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Clamp the workpiece on the workpiece spindle (4); S2: The mounting reference surface of the workpiece is ground by the first spindle (7) to establish the positioning reference for subsequent tooth profile machining; S3: The second main shaft (8) is raised or lowered along the Y-axis to the working position by means of the lifting mechanism; S4: The second spindle (8) is swung to a first angle corresponding to straight gear machining or a second angle corresponding to helical gear machining by means of the swing angle device; S5: The tooth profile of the workpiece is ground by the second spindle (8) with the mounting reference surface processed in step S2 as the positioning reference.

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