Device for measuring stress in operation process of medium-large low-speed tapered roller bearing retainer

Abstract

The utility model relates to the technical field of bearing testing, in particular to a stress measuring device for a middle-large low-speed tapered roller bearing retainer in an operation process, which comprises a testing machine, a bearing support and a measuring device, the strain gauge group is adhered to a specific part of a retainer of the bearing; the input end of the lead is connected with the strain gauge group; the lead is fixed on the large end surface or the outer side surface of the retainer in a bundling manner; a rotor of the slip ring device is connected with the output ends of the bundled wires, and a stator and the rotor are in rolling fit to transmit signals; the signal acquisition equipment is connected with a stator of the slip ring device through a compensation bridge; wherein a driving shaft of the motor is in transmission connection with the slip ring rotor, so that the slip ring rotor, the wire and the retainer synchronously rotate at the same speed. The scheme has the advantages that the dynamic stress change in the operation process of the retainer is monitored in real time, the structural design of the retainer is optimized, and the operation reliability is improved.

Description

Technical Field

[0001] This utility model relates to the field of bearing testing technology, and in particular to a stress measurement device for the cage operation process of medium and large low-speed tapered roller bearings. Background Technology

[0002] As a key component of bearings, the bearing cage's main functions are to evenly separate the rolling elements, guide their movement, and prevent direct collisions. This plays a crucial role in reducing friction and wear and extending bearing life. Currently, the design of small and medium-sized bearing cages mainly relies on experience or reverse engineering of foreign products. However, medium and large tapered roller bearings (outer diameter 0.5-2 meters) used in wind power face even more severe technical challenges. Under harsh operating conditions of huge axial and radial loads and overturning moments, the structural reliability of the cage directly affects the operational stability of the entire bearing system.

[0003] Existing technologies have significant drawbacks: Firstly, the lack of systematic design specifications and testing standards for medium and large-sized wind turbine bearing cages makes it impossible to obtain effective stress distribution data during the design phase. Secondly, traditional bearing testing machines can only test the overall performance of the complete bearing assembly and cannot monitor the dynamic stress changes of the cage during operation in real time. This testing blind spot makes cage design optimization lack a theoretical basis, often leading to fracture failures only being discovered after mass application, posing significant safety hazards to wind turbine operation. In particular, for tapered roller bearings operating under low-speed, heavy-load conditions, stress concentration in critical areas such as the cage pocket area and crossbeam connections is difficult to detect using conventional methods, severely restricting the optimization and improvement of the cage structure.

[0004] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide a stress measurement device for the cage operation process of medium and large low-speed tapered roller bearings, which has the advantages of real-time monitoring of dynamic stress changes during cage operation, optimizing cage structural design, and improving operational reliability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This application provides a stress measurement device for the cage of a medium-to-large low-speed tapered roller bearing during operation, the technical solution of which is as follows: (Includes:)

[0008] • Testing machine, used for installing bearings;

[0009] • An assembly of strain gauges bonded to specific locations on the bearing cage;

[0010] • The wires are bundled and fixed to the large end face or outer side of the cage, and their input ends are connected to the strain gauge assembly;

[0011] • A motor-driven slip ring device, in which the rotor is connected to the output end of multiple bundled wires, and the stator and rotor roll together to transmit signals;

[0012] • The signal acquisition equipment connects the stator of the slip ring device through a compensation bridge; the drive shaft of the motor is connected to the slip ring rotor, so that the slip ring rotor and the wires rotate synchronously and at the same speed as the cage.

[0013] This technical solution achieves real-time acquisition of cage stress under rotating conditions by constructing a dynamic stress measurement system. The testing machine provides a realistic installation foundation for the bearing, ensuring that the testing environment is consistent with actual applications; the strain gauge assembly directly contacts the high-stress area of ​​the cage, accurately capturing stress changes; the wires avoid tangling or breakage during rotation, ensuring signal transmission stability; the slip ring device solves the signal transmission problem between rotating components and stationary equipment through rolling contact between the stator and rotor; the signal acquisition equipment, combined with a compensating bridge, eliminates interference signals and improves measurement accuracy. The core innovation lies in the motor-driven synchronous rotation of the slip ring rotor and the cage at the same speed, eliminating relative movement between the wires and rotating components, completely eliminating the problems of wire tangling or signal interruption caused by speed differences in traditional measurements, and providing a physical basis for continuously acquiring dynamic stress data.

[0014] The assembly process involves first installing the bearing inner ring assembly onto the testing machine, then attaching strain gauges to specific locations on the cage, and finally bundling the lead wires at a fixed position on the large end of the cage. The outer ring is then installed onto the inner ring assembly. The strain gauge lead wires are connected to the signal acquisition equipment via a motor-driven slip ring device. The motor drives the slip ring and the strain gauge lead wires to rotate at the same speed as the cage. During bearing rotation, the cage strain information is collected via the strain gauges, lead wires, and slip ring, and then connected to the compensation bridge and signal acquisition equipment.

[0015] This invention solves the problem of difficulty in installing sensors and connecting wires during bearing operation due to the small internal space of the bearing and the different rotation speeds of the cage and inner and outer rings. The multi-way slip ring rotates in the same direction and at the same speed as the cage, and the strain gauge wires avoid the problem of wire entanglement during rotation after passing through the multi-way slip ring.

[0016] Furthermore, this application also proposes that the strain gauge group is distributed on the outer side of the large end of the cage pocket, the outer side of the junction between the large end of the cage pocket and the crossbeam, the outer side of the small end of the cage pocket, or the outer side of the junction between the small end of the cage pocket and the crossbeam.

[0017] Furthermore, this application proposes that the strain gauge assembly comprises multiple strain gauges, which are adhered and fixed to the crossbeam between two pockets on the cage. This technical solution achieves precise stress monitoring of weak points in the cage by placing multiple strain gauges in the crossbeam region between the two pockets. Specifically, the strain gauge assembly is arranged on the crossbeam between the two pockets because this area bears alternating loads and complex stresses during bearing operation, making it a critical area in the cage structure most prone to stress concentration. The combined arrangement of multiple strain gauges allows for the capture of multi-dimensional strain data of the crossbeam in the circumferential, radial, and axial directions from different angles, overcoming the limitations of single strain gauge measurements. By directly adhering and fixing the strain gauges to the crossbeam surface, a rigid connection between the strain sensing element and the measured part is ensured, thereby accurately transmitting mechanical deformation signals and providing reliable raw data for subsequent establishment of a cage mechanical model.

[0018] Furthermore, this application proposes that the wire bead be bonded to the end face or outer surface of the cage's large-end crossbeam extension line using a fixing adhesive. This technical solution achieves reliable wire fixation through structural optimization and material combination. The fixing adhesive ensures that the wire will not touch the rollers or loosen and fall off during operation, thus not affecting the normal operation of the cage. Choosing the end face or outer surface of the cage's large-end crossbeam extension line as the bonding area utilizes the fact that this area is far from the movement trajectory of the cage pocket, avoiding contact interference between the wire and the rolling elements or raceways; on the other hand, the high structural rigidity of the crossbeam extension line area makes it less prone to adhesive layer cracking due to deformation after bonding. The two optional positions, end face and outer surface, adapt to different bearing installation space constraints. End face bonding reduces radial space occupation, while outer surface bonding facilitates maintenance and inspection of the wire harness after installation.

[0019] Furthermore, this application proposes that after the inner ring assembly of the bearing is installed on the testing machine, strain gauge sets are attached to specific locations on the cage, and the wires are led out and bundled at the large end of the cage before finally installing the outer ring onto the inner ring assembly. This technical solution achieves reliable integration of the sensor system through phased assembly. First, the inner ring assembly is installed on the testing machine, establishing a stable testing benchmark platform for the cage; attaching strain gauge sets to specific locations on the cage ensures that the sensor can accurately capture the stress distribution of key structures such as the crossbeam; by leading the wires out and bundling them at the large end of the cage, the risk of wire entanglement is avoided, and the stability of the signal transmission path is ensured; finally, the process design for installing the outer ring assembly ensures the integrity of the bearing structure and avoids damage to the sensor system due to compression during the final assembly process. This step-by-step assembly process effectively solves the sensor installation problem caused by the enclosed structure of large bearings, ensuring the coordinated operation of the testing system and the bearing body.

[0020] Furthermore, this application proposes that the stator of the slip ring device is constructed as a fixed outer sleeve, and the rotor is constructed as a rotating shaft rotatably disposed within the fixed outer sleeve. Multiple conductive rings are arranged on the outer surface of the rotating shaft, and brushes that roll in contact with the conductive rings are arranged on the inner wall of the fixed outer sleeve. This technical solution achieves dynamic signal transmission by constructing a mating structure between the fixed outer sleeve and the rotating shaft. Designing the stator as a fixed outer sleeve allows for a stable connection with the testing machine, preventing the signal acquisition equipment from rotating with the rotor. Constructing the rotor as a rotating shaft allows it to rotate synchronously with the cage, eliminating the risk of wire entanglement. Multiple conductive rings on the outer surface of the rotating shaft, combined with the rolling contact brushes on the inner wall of the fixed outer sleeve, form a multi-point contact conductive path, ensuring independent transmission of signal channels from different strain gauges. The rolling contact design between the conductive rings and the brushes reduces signal interference caused by friction compared to traditional sliding contact methods, improving signal transmission stability under high-speed rotation conditions.

[0021] Furthermore, this application also proposes that the rotating shaft is constructed as a hollow shaft, and the drive shaft of the motor is inserted into the shaft hole of the rotating shaft.

[0022] As can be seen from the above, the stress measurement device and method for the cage operation process of medium and large low-speed tapered roller bearings provided in this application, through the synergistic effect of the testing machine, strain gauge group, slip ring device and signal acquisition equipment, realizes the real-time monitoring of dynamic stress in key parts during cage operation, solves the technical problem that traditional testing methods cannot capture dynamic stress changes, and has the advantages of real-time monitoring of dynamic stress changes during cage operation, optimizing cage structural design and improving operational reliability. Attached Figure Description

[0023] Figure 1 A schematic diagram of a cage operation stress measurement device provided in this application.

[0024] Figure 2 The present application provides a schematic diagram of the strain gauge installation location and wire fixing.

[0025] Figure 3 The present application provides a cross-sectional schematic diagram of the slip ring device. Detailed Implementation

[0026] The embodiments of this utility model 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 intended to explain this utility model, and should not be construed as limiting this utility model.

[0027] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0029] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] In existing technologies, the medium and large tapered roller bearings 10 used in the wind power field lack real-time monitoring methods for cage stress 4, resulting in a lack of theoretical support for design optimization. Traditional testing methods cannot capture dynamic stress changes during operation. Due to the limited internal space of the bearing 10 and the speed difference between the cage 4 and the inner and outer rings, the sensor wires 3 are prone to entanglement or breakage during rotation, making it difficult to guarantee signal transmission stability.

[0032] To solve the above problems, such as Figure 1-3 As shown, this application proposes a stress measurement device for the cage 4 of a medium-to-large low-speed tapered roller bearing 10 during operation, comprising a testing machine, a strain gauge set 5, a wire 3, a motor-driven slip ring device 2, and a signal acquisition device. The testing machine is used to install the bearing 10. The strain gauge set 5 is attached to a specific location on the cage 4. The input end of the wire 3 is connected to the strain gauge set 5, and the output end is connected to the slip ring rotor 21. The signal acquisition device is connected to the slip ring stator 22 via a compensating bridge. The motor drive shaft 11 is connected to the slip ring rotor 21, causing the slip ring rotor 21 and the wire 3 to rotate synchronously and at the same speed as the cage 4.

[0033] The testing machine refers to a testing platform that can simulate the actual working conditions of the bearing 10. Specifically, it can be implemented using a hydraulic loading test bench, used to fix the inner and outer rings of the bearing 10 and apply a set load. The strain gauge group 5 refers to a measurement unit composed of multiple resistance strain gauges 51, specifically foil strain gauges, bonded to the surface of the cage 4 beam 42 with epoxy resin, used to convert mechanical strain into electrical signals. The bundled lead-out of multiple wires 3 refers to the integrated and fixed structure of multiple signal lines, preventing the wire bundle from swinging during rotation. The slip ring device 2 refers to the electromechanical equipment that realizes signal transmission between the rotating body and the stationary component, specifically a multi-channel precious metal contact slip ring. Its rotor 21 is connected to the wires 3 and rotates with the cage 4, while the stator 22 maintains contact with the conductive ring track 23 through brushes 24. The compensation bridge refers to a circuit module that eliminates the influence of temperature drift, specifically a Wheatstone bridge circuit, used to correct interference components in the strain gauge 51 measurement signal.

[0034] Specifically, after the inner ring assembly 102 of bearing 10 is installed on the testing machine, strain gauge group 5 is attached to the crossbeam 42 of cage 4. Wires 3 are led out along the large end of cage 4, bundled, and connected to slip ring rotor 21. After the outer ring 103 is installed, the motor drives slip ring rotor 21 to rotate synchronously with cage 4. During operation, strain gauge 51 converts mechanical deformation into resistance change. The signal is transmitted to slip ring rotor 21 via wires 3, and then output to a compensation bridge for temperature compensation via stator brush 24. Finally, dynamic stress data is recorded by signal acquisition equipment. The synchronous rotation speed of slip ring rotor 21 and cage 4 eliminates torsional stress in wires 3, and the bundled fixing method avoids interference between the wire harness and bearing 10 components. Through the above technical solution, this application achieves continuous monitoring of dynamic stress during cage 4 operation, avoiding the problem of wire 3 entanglement and breakage due to speed differences. The measurement data accurately reflects the stress distribution state of cage 4 under real working conditions, providing direct experimental basis for optimizing the structural design of cage 4. The synchronous control mechanism of slip ring device 2 and cage 4 ensures the stability of signal transmission, and the compensation bridge effectively eliminates the influence of ambient temperature on measurement accuracy.

[0035] In a further embodiment, strain gauge arrays 5 are distributed on the outer side of the large end of the cage 4 pocket 41, the outer side of the junction between the large end of the pocket 41 and the crossbeam 42, the outer side of the small end of the pocket 41, or the outer side of the junction between the small end of the pocket 41 and the crossbeam 42. Specifically, the outer side of the large end of the pocket 41 refers to the outer peripheral edge of the contact area between the cage 4 and the roller, which can be achieved by polishing the surface of a metal substrate and then attaching strain gauges 51 to it, used to capture the contact stress generated by the circumferential movement of the roller. The outer side of the junction between the large end of the pocket 41 and the crossbeam 42 refers to the transition area between the crossbeam 42 and the large end structure of the cage 4, which can be achieved by covering the corner of the structure with curved surface-adaptive strain gauges 51, used to monitor the bending stress at the root of the crossbeam 42. The outer side of the small end of the pocket 41 refers to the outer surface of the cage 4 that axially constrains the movement of the roller, which can be achieved by arranging an array of micro-strain gauges 51, used to detect the compressive stress generated by the axial load transfer. The outer side of the junction between the small end of the pocket 41 and the crossbeam 42 refers to the mechanical transmission area between the crossbeam 42 and the small end structure. Specifically, it can be achieved by using biaxial strain gauges 51 arranged in a cross pattern to obtain the torsional stress components.

[0036] exist Figure 2 In the specific embodiment shown, the strain gauge group 5 includes multiple strain gauges 51, which are glued and fixed to the crossbeam 42 between two pockets 41 on the cage 4. The strain gauge group 5 refers to a combined unit composed of multiple strain sensing elements, specifically resistive strain gauges, with each strain gauge 51 independently measuring local deformation. Multiple strain gauges 51 refer to three or more sensing elements with different measurement directions, specifically arranged orthogonally, for synchronously acquiring strain data in different dimensions. The crossbeam 42 is the supporting component in the cage 4 structure connecting adjacent pockets 41, bearing periodic alternating loads when the bearing 10 is in operation. Specifically, during the assembly of the cage 4, three strain gauges 51 are arranged orthogonally in the central area of ​​the crossbeam 42 surface. When the bearing 10 is in operation, the crossbeam 42 is subjected to a combination of radial pressure and rotational centrifugal force from the rollers, and the orthogonally arranged strain gauges 51 respectively capture circumferential bending strain, radial compressive strain, and axial tensile strain. Three sets of strain signals are separated and transmitted to the acquisition device via a compensating bridge to form three-dimensional stress distribution data of the crossbeam 42 region. The combined arrangement of multiple strain gauges 51 effectively eliminates data deviation in a single measurement direction, fully reflecting the true stress state of the crossbeam 42 under dynamic working conditions. Through the above technical solution, this application can accurately obtain multi-directional strain data of the cage 4 crossbeam 42 when the bearing 10 is in operation, and accurately identify the location and intensity change law of stress concentration areas. The measured three-dimensional stress distribution data provides a quantitative basis for optimizing the cross-sectional shape of the crossbeam 42 and adjusting the wall thickness parameters, effectively avoiding fracture failure caused by excessive local stress.

[0037] In the specific design, the conductor 3 is adhered to the end face or outer surface of the extended line of the cage 4's large end beam 42 using a fixing adhesive 6. The fixing adhesive 6 refers to using an adhesive with high bonding strength and fatigue resistance to fix the conductor 3. Specifically, epoxy resin or polyurethane adhesives can be used. After curing, the adhesive forms a flexible adhesive layer to resist centrifugal force and vibration. The end face or outer surface of the extended line of the cage 4's large end beam 42 refers to the structural surface extending outward from the cage 4's large end beam 42. The position of the extended line can be determined by geometric projection. This area is far from the movement trajectory of the cage 4's pocket 41 and has high structural rigidity, thereby preventing the conductor 3 from contacting the rolling elements and reducing adhesive layer cracking due to deformation.

[0038] Specifically, the wire 3 is fixed to the extension line of the crossbeam 42 at the large end of the cage 4 using adhesive 6. The adhesive covers the contact area between the wire 3 and the surface of the cage 4, forming a uniformly distributed adhesive interface. During the rotation of the cage 4, the flexibility of the adhesive absorbs mechanical vibration energy, while its high adhesive strength ensures that the wire bundle 3 does not shift or fall off under centrifugal force. When choosing the end face or the outer side as the fixing position, end face bonding extends the wire 3 axially, reducing radial space occupation; outer side bonding extends the wire 3 circumferentially, facilitating visual inspection or maintenance of the wire bundle 3 after installation. Through the above technical solution, this application effectively solves the problem of wire 3 falling off and shifting due to centrifugal force or vibration, ensuring signal transmission stability; by optimizing the fixing position of the wire 3, contact interference with the rolling elements or raceways is avoided, ensuring the normal operation of the cage 4; at the same time, it provides optional fixing methods of end face and outer side to adapt to different bearing 10 installation space limitations, improving the applicability of the solution.

[0039] This application further proposes that after the inner ring assembly 102 of the bearing 10 is installed on the testing machine, strain gauge sets 5 are attached to specific locations on the cage 4, and wires 3 are led out after being fixed at the large end of the cage 4. Finally, the outer ring 103 is installed onto the inner ring assembly 102. The installation of the inner ring assembly 102 onto the testing machine refers to pre-assembling the assembly consisting of the inner ring, rollers, and cage 4 of the bearing 10 onto the main shaft of the testing machine, providing a stable reference platform for subsequent sensor installation. The attachment of strain gauge sets 5 to specific locations on the cage 4 refers to arranging strain sensors in stress concentration areas such as the crossbeam 42 and the edge of the pocket 41 of the cage 4. This can be achieved using epoxy resin adhesive bonding to ensure a tight fit between the sensor and the substrate surface. The installation of the outer ring onto the inner ring assembly 102 refers to fitting the outer ring of the bearing 10 onto the outside of the rollers after the sensor arrangement is completed on the inner ring assembly 102, preventing damage to the already arranged sensor system during outer ring installation. Specifically, the phased assembly process involves disassembling the bearing 10 into two parts: the inner ring assembly 102 and the outer ring. First, the inner ring assembly 102 is fixed to the main shaft of the testing machine. At this time, the cage 4 is fully exposed, facilitating the precise attachment of the strain gauge assembly 5 in key areas such as the crossbeam 42. After the wire 3 is fixed along the large end face of the cage 4, the signal transmission path is constrained to a preset position, preventing the wire from tangling with moving parts during subsequent assembly. Finally, the outer ring installation process is carried out after the sensor system is arranged. By controlling the assembly sequence of the outer ring and inner ring assembly 102, the spatial limitations on sensor wiring imposed by the enclosed bearing 10 structure are effectively avoided. Through the above technical solution, this application solves the problem of insufficient sensor installation space caused by the enclosed structure of medium and large bearings 10, avoids physical damage to the already arranged sensor system during the outer ring assembly process, ensures the positioning accuracy and signal transmission stability of the strain gauge assembly 5 and the wire 3, and provides a reliable hardware arrangement scheme for stress testing of the cage 4.

[0040] like Figure 3As shown, the stator 22 of the slip ring device 2 is constructed as a fixed sleeve, and the rotor 21 is constructed as a rotating shaft rotatably disposed within the fixed sleeve. Multiple conductive ring channels 23 are provided on the outer surface of the rotating shaft 21, and brushes 24 that roll in contact with the conductive ring channels 23 are provided on the inner wall of the fixed sleeve. The fixed sleeve refers to a stationary component that is fixedly connected to the testing machine; it can be made of metal and machined into an annular sleeve structure. Its inner wall has mounting positions for the brushes 24, used to fix the connection lines of the signal acquisition equipment. The rotating shaft 21 refers to a rotating component that rotates synchronously with the cage 4; it can be made of a hollow shaft structure, with annular grooves machined on its outer surface to form conductive ring channels 23, used to connect to the output end of the wire 3 and transmit strain signals. The conductive ring channels 23 refer to annular conductive areas distributed circumferentially along the rotating shaft 21; they can be made by plating with copper alloy material or embedding conductive rings. Each conductive ring channel 23 corresponds to an independent signal transmission channel. Among them, the brush 24 refers to the conductive element that keeps in contact with the conductive ring 23. Specifically, it can be implemented by a carbon brush or a metal brush structure. A spring mechanism makes it roll in contact with the conductive ring 23 to ensure the stability of the contact pressure during rotation.

[0041] In the specific design, the fixed outer sleeve is fixedly connected to the testing machine frame via flanges or bolts, and the internal brush 24 is connected to the signal acquisition device via wire 3. The rotating shaft 21 is mounted inside the fixed outer sleeve via bearings, and its hollow shaft structure allows the motor drive shaft 11 to be directly inserted for power transmission. The wire 3 is bundled after being led out from the cage 4 and connected to the terminal at the end of the rotating shaft 21 and the conductive loop 23. When the motor drives the rotating shaft 21 to rotate, the conductive loop 23 rotates with the shaft, and the brush 24 maintains rolling contact with the conductive loop 23 under the action of springs. The strain signal is transmitted to the signal acquisition device through the contact interface between the conductive loop 23 and the brush 24. Since the brush 24 and the conductive loop 23 use rolling contact rather than sliding friction, the contact resistance fluctuation is effectively suppressed, and the signal transmission stability is improved. Through the above technical solution, this application solves the problem of wire 3 entanglement caused by the rotation of the cage 4, ensuring stable transmission of the strain signal under dynamic rotation conditions. The rolling contact design between the conductive ring 23 and the brush 24 reduces contact resistance fluctuations and noise interference during signal transmission, meeting the stress monitoring requirements of the cage 4 of medium and large bearings 10 during long-term high-speed operation. The independent layout of multiple conductive rings 23 enables the synchronous acquisition of signals from multiple strain gauges 51, providing complete data support for stress distribution analysis of the cage 4.

[0042] In a specific implementation, the rotating shaft 21 is constructed as a hollow shaft, and the drive shaft 11 of the motor 1 is inserted into the shaft hole of the rotating shaft 21. The hollow shaft refers to a rotating shaft structure with an axially through-hole inside. Specifically, it can be achieved by machining a metal tube to form a cylindrical structure with an inner hole and outer surface coaxial, and its internal hole is used to accommodate the motor drive shaft 11. The drive shaft 11 being inserted into the shaft hole means that the motor output shaft and the hollow shaft are connected by an interference fit or keyway. Specifically, this can be achieved by setting a keyway on the inner wall of the shaft hole and assembling a flat key at the end of the drive shaft 11 to achieve circumferential positioning, ensuring no relative slippage during power transmission. The hollow shaft structure allows the motor drive shaft 11 to be embedded in its internal hole, forming a coaxial nested transmission layout. When the motor starts, the drive shaft 11 directly transmits torque to the rotating shaft 21 through the rigid connection of the insertion part, driving the slip ring rotor 21 and the cage 4 to rotate synchronously. Since there is no intermediate transmission component between the rotating shaft 21 and the drive shaft 11, no phase difference or speed fluctuation will occur during rotation, thus avoiding the wire 3 from getting tangled or stretched during rotation.

[0043] In a specific design, the rotor of the slip ring device is driven by a motor and rotates at the same speed as the cage. The strain gauge wires are connected to the rotating part, and the motor speed is determined by the cage speed, typically as follows:

[0044]

[0045] In the formula, n is the cage speed, n0 is the bearing inner ring speed, and D we D is the equivalent diameter of the roller. pw Let α be the pitch circle diameter and α be the contact angle.

[0046] The motor speed is controlled based on the above formula, so that the rotor speed of the motor-driven slip ring device is synchronized with the cage speed, thus avoiding the problem of wire entanglement and breakage caused by speed difference.

[0047] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A medium to large size low speed tapered roller bearing cage in operation stress measuring device characterized by, include: - Testing machine, used for installing bearings (10); - Strain gauge assembly (5) attached to a specific part of the cage (4) of the bearing (10); - The wires (3) are bundled and fixed to the large end face or outer side of the cage, and their input ends are connected to the strain gauge group (5); - A motor-driven slip ring device (2), whose rotor (21) is connected to the output end of multiple wires (3) after being bundled, and the stator (22) and the rotor (21) roll together to transmit signals; - Signal acquisition equipment, connected to the stator (22) of slip ring device (2) via a compensation bridge; The drive shaft (11) of the motor (1) is connected to the rotor (21) so that the slip ring rotor (21) and the wire (3) rotate synchronously and at the same speed with the cage (4).

2. The stress measuring device for the cage operation process of a medium-to-large low-speed tapered roller bearing according to claim 1, characterized in that: The strain gauge group (5) is distributed on the outer side of the large end of the cage pocket (41), the outer side of the junction between the large end of the pocket (41) and the crossbeam (42), the outer side of the small end of the pocket (41), or the outer side of the junction between the small end of the pocket (41) and the crossbeam (42).

3. The stress measuring device for the cage operation process of a medium-to-large low-speed tapered roller bearing according to claim 2, characterized in that: The strain gauge assembly (5) includes multiple strain gauges (51) which are glued and fixed to the crossbeam (42) between two pockets (41) on the retainer.

4. The stress measuring device for the cage operation process of a medium-to-large low-speed tapered roller bearing according to claim 3, characterized in that: The conductor (3) is fixed to the end face or outer side of the extension line of the cage large end crossbeam (42) by fixing glue (6).

5. The stress measuring device for the cage operation process of a medium-to-large low-speed tapered roller bearing according to claim 1, characterized in that: After the inner ring assembly (102) of the bearing (10) is installed on the testing machine, strain gauge groups (5) are pasted on a specific part of the cage (4), and wires (3) are led out after being fixed at the large end of the cage. Finally, the outer ring (103) is installed on the inner ring assembly (102).

6. The stress measuring device for the cage operation process of a medium-to-large low-speed tapered roller bearing according to claim 1, characterized in that: The stator (22) of the slip ring device (2) is constructed as a fixed sleeve, and the rotor (21) is constructed as a rotating shaft rotatably disposed within the fixed sleeve; multiple conductive ring channels (23) are provided on the outer surface of the rotating shaft, and brushes (24) that roll in contact with the conductive ring channels (23) are provided on the inner wall of the fixed sleeve.

7. The stress measuring device for the cage operation process of a medium-to-large low-speed tapered roller bearing according to claim 6, characterized in that: The rotating shaft is constructed as a hollow shaft, and the drive shaft (11) of the motor (1) is inserted into the shaft hole of the rotating shaft.

8. The stress measuring device for the cage operation process of a medium-to-large low-speed tapered roller bearing according to claim 1, characterized in that: The rotor (21) of the slip ring device (2) rotates at the same speed as the cage (4), and the speed of the motor (1) is determined by the speed of the cage: where n is the raceway rotational speed, n0 is the inner ring rotational speed of the bearing (10), D we is the equivalent diameter of the roller, D pw is the pitch diameter, and a is the contact angle.

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