Low-noise downhole generator testing device, testing table, testing vehicle and testing method

Abstract

This invention provides a low-noise downhole generator testing device, test bench, test vehicle, and testing method, solving the problems of high vibration and noise affecting test results in existing test benches. The device includes a generator clamping housing, a transmission assembly containing a variable frequency motor, two multi-wedge pulleys, and a multi-wedge belt. The variable frequency motor is mounted on the upper surface of the clamping housing. The first multi-wedge pulley is connected to the motor shaft, and the second multi-wedge pulley is fixed to the housing via a magnet assembly. The magnet assembly is installed in the annular space between the generator's outer wall and the inner wall of the housing. A bearing assembly is located on the outer ring of the magnet assembly and includes a bearing housing, a bearing, a tolerance ring between the bearing housing housing and the bearing housing, and a sealing ring between the bearing housing and the inner wall of the housing. The bearing housing is fixed to the housing by fasteners with elastic pre-tightening elements at the tail end. A vibration-damping foot is mounted on the lower surface of the clamping housing, with a tapered elastic pad at the lower end to prevent contact between the device and the platform. Through multi-stage vibration damping, operating noise is significantly reduced, and testing accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of testing rotary steering generators, and more specifically, to a low-noise downhole generator testing device, test bench, test vehicle, and testing method. Background Technology

[0002] The downhole generator of this invention is the core power source for measurement-while-drilling (MSD), logging-while-drilling (LOD), and rotary steerable drilling systems, and its performance directly affects the reliability and stability of downhole tools. Due to their small size, high power density, and harsh working environment, performance testing and quality evaluation of rotary steerable downhole generators, both newly manufactured and after maintenance, are particularly important. Currently, conventional generator test benches generally suffer from large size and significant operating noise, causing considerable noise interference to personnel who frequently use the equipment, and may also lead to deviations in performance and quality evaluation results due to the inability to accurately identify abnormal generator noises.

[0003] Various generator testing devices have been disclosed in the prior art. For example, Chinese patent CN121026629A discloses a variable-diameter intelligent downhole turbine generator test bench, including a generator fixing module, a magnetic ring clamping module, and a drive digital display module. The generator fixing module uses a lead screw motor to drive a push-clamp slider to fix the generator. The magnetic ring clamping module uses a hollow geared motor to drive a clamping slider to clamp the magnetic ring. The drive digital display module uses a synchronous belt and pulley motor to transmit power to the hollow pulley, thereby driving the magnetic ring to rotate. This solution, through its intelligent variable-diameter clamping device, can test downhole turbine generators of different sizes and power ratings, and has a wide range of applications.

[0004] However, the aforementioned existing technologies still have the following shortcomings: Firstly, the problem of operating noise has not been effectively resolved. CN121026629A uses a synchronous belt drive, which transmits power through the meshing of the belt teeth and pulley teeth. The teeth generate periodic impact noise during engagement and disengagement, and the axial arrangement of the teeth causes significant airflow disturbance during pulley rotation, resulting in prominent high-frequency noise. Furthermore, the bearing outer ring and bearing housing use a clearance fit in this design, which generates vibration and noise at high speeds. In addition, the vibration of the motor and transmission system is directly transmitted to the frame and platform through rigid connections, further exacerbating noise radiation.

[0005] Secondly, the rigid coupling between the transmission system and the generator rotor leads to a complex vibration transmission path. The pulley motor drives the hollow pulley to rotate via the synchronous belt, which in turn drives the magnetic ring to rotate. The magnetic ring then drives the generator rotor through magnetic coupling. However, the vibration generated by the synchronous belt drive itself is directly transmitted to the magnetic ring and generator through rigid components such as pulleys and bearings, affecting the test accuracy.

[0006] Third, existing test benches use a rigid connection to fix the equipment to the metal platform, and vibration is efficiently transmitted through the metal-to-metal contact surface, lacking effective vibration isolation measures. Summary of the Invention

[0007] The purpose of this invention is to provide a low-noise downhole generator testing device, test bench, test vehicle, and testing method, aiming to solve the technical problems of large vibration, significant noise, interference with testing accuracy, and poor working environment for operators in existing generator test benches during operation.

[0008] The embodiments of the present invention are implemented as follows: A low-noise downhole generator testing device, comprising: The generator clamping housing is a cylindrical structure with a through-type cylindrical inner cavity for accommodating a rotary steerable downhole generator; the outer wall of the generator clamping housing is symmetrically cut with an upper and lower plane; The transmission assembly includes a variable frequency motor, a first multi-ribbed pulley, a second multi-ribbed pulley, a generator locking sleeve, and a multi-ribbed belt. The variable frequency motor is mounted on the upper surface of the generator clamping housing. The first multi-ribbed pulley is connected to the output shaft of the variable frequency motor. The second multi-ribbed pulley is fixed relative to the generator clamping housing through a magnet assembly. The multi-ribbed belt connects the first multi-ribbed pulley and the second multi-ribbed pulley to form a transmission pair. The magnet assembly is assembled in the annular space formed between the outer wall of the generator and the inner wall of the generator clamping housing; The bearing assembly is assembled in an annular space and located on the outer ring of the magnet assembly. The bearing assembly includes a bearing housing, a bearing installed in the bearing housing, a tolerance ring disposed between the bearing housing housing and the bearing housing, and a sealing ring disposed between the inner wall of the bearing housing and the generator clamping housing. The bearing housing is fixedly connected to the generator clamping housing by a fastener with an elastic preload element at the tail. The shock-absorbing foot is installed on the lower surface of the generator clamping housing. The lower end of the shock-absorbing foot is provided with a tapered elastic pad for embedding into the test platform, so that the generator clamping housing, generator locking sleeve, and second multi-wedge pulley do not contact the test platform. The smaller diameter end of the generator is inserted into the oval cross-section end of the generator clamping housing and extends to the outside of the annular cross-section end; the magnet assembly and bearing assembly are sequentially fitted onto the smaller diameter end of the generator and are housed together in the annular space between the outer wall of the generator and the inner wall of the generator clamping housing, and are fastened using a generator locking sleeve.

[0009] In a preferred embodiment of the present invention, the outer wall of the aforementioned generator clamping housing is symmetrically cut with an upper plane and a lower plane. The cut length of the upper / lower plane is less than the length of the generator clamping housing, and the cut thickness is less than the cylindrical thickness of the generator clamping housing. This makes one end of the generator clamping housing have an annular cross-section, and the other end has an oval cross-section with a central circular hollow. An axially extending opening groove is provided in the middle of the arc-shaped edge of the oval cross-section cylindrical wall. The through-type cylindrical inner cavity includes a first inner cavity and a second inner cavity. The first inner cavity is located at the annular end and has a diameter greater than that of the second inner cavity. The first inner cavity and the second inner cavity are connected by a first through hole, the diameter of which is smaller than that of the second inner cavity. The bottom of the second inner cavity has a tapered surface.

[0010] In a preferred embodiment of the present invention, the first multi-wedge pulley and the second multi-wedge pulley adopt the same annular wedge pulley tooth profile, the annular wedge pulley tooth profile is a 40° rounded corner tooth, the rounded corner R=0.3mm, the rounded corner tooth depth is 0.06±0.25mm; the wedge spacing e=2.34±0.03mm, and the effective diameter de is 2.99±0.02mm.

[0011] In a preferred embodiment of the present invention, the outer diameter of both the first and second multi-wedge pulleys is 67.5 mm, the center distance is 134 mm, and the transmission ratio of the transmission assembly is 1:1. The first multi-wedge pulley has a circular hole with a radial rectangular groove in the middle. The circular hole has a diameter of 19 mm, and a rectangular groove extends radially outward from its circumferential edge. The width of the rectangular groove is 6 mm along the circumferential direction, and the radial depth is 2.5 mm, so that the distance from the outer side of the rectangular groove (i.e., the side away from the center) to the farthest point opposite the circular hole is 21.5 mm. The second multi-wedge pulley has a circular through hole with a diameter of 55 mm in the middle.

[0012] In a preferred embodiment of the present invention, the above-mentioned magnet assembly includes: a magnet, a magnetic strip, and a magnet housing. The magnet is sleeved on the outer wall of the generator, the magnetic strip is sleeved on the outside of the magnet, and the magnet housing is sleeved on the outside of the magnetic strip, so that the magnetic strip is encapsulated in the annular cavity formed by the outer wall of the generator, the magnet, and the magnet housing.

[0013] In a preferred embodiment of the present invention, the bearing assembly includes a first bearing and a second bearing arranged sequentially along the axial direction, and a tolerance ring is provided between the outer ring of each bearing and the corresponding bearing housing.

[0014] In a preferred embodiment of the present invention, the fastener with an elastic preload element at the tail is a screw, and the elastic preload element is a helical spring sleeved on the tail of the screw, wherein the helical spring has a wire diameter of 1 mm, a mean diameter of 7 mm, and a pitch of 2 mm.

[0015] In a preferred embodiment of the present invention, the above-mentioned shock-absorbing foot further includes a shock-absorbing frame and a shock-absorbing bolt. The upper part of the shock-absorbing frame is connected to the lower plane of the generator clamping housing through the shock-absorbing bolt. A tapered elastic pad is disposed on the bottom outer wall of the shock-absorbing frame, and the outer diameter of the tapered elastic pad gradually decreases from top to bottom.

[0016] The present invention also provides a low-noise downhole generator test bench, including the test device of any of the foregoing, and a wooden platform; the tapered elastic pads of the shock-absorbing feet of the test device are embedded in the wooden platform or in direct contact with the wooden platform, so that a non-rigid connection is formed between the test device and the wooden platform.

[0017] The present invention also provides a low-noise downhole generator test vehicle, including the aforementioned test platform and multiple casters installed under the wooden platform, the casters being swivel wheels or directional wheels with braking devices.

[0018] The present invention also provides a method for testing a low-noise downhole generator, using any of the aforementioned testing devices, or the aforementioned test bench, or the aforementioned test vehicle, comprising the following steps: The magnet assembly and bearing assembly are sequentially assembled onto the generator clamping housing. When assembling the bearing assembly, a tolerance ring is placed between each bearing housing and the bearing housing, and a sealing ring is pressed between the bearing housing and the inner wall of the generator clamping housing. The bearing housing is fixed to the generator clamping housing using screws with helical springs at the tail. The elastic deformation of the helical springs provides a constant preload and absorbs high-frequency vibrations. The tapered elastic pad at the bottom of the shock-absorbing foot is embedded in the wooden platform, so that the entire test device forms a non-rigid contact with the wooden platform, thereby avoiding direct contact between the generator and the test device and the rigid platform; the variable frequency motor of the transmission component is assembled onto the upper plane of the generator clamping shell, and the first multi-ribbed pulley is assembled on the variable frequency motor; the second multi-ribbed pulley is assembled on the generator locking sleeve, and the multi-ribbed belt connects the first multi-ribbed pulley and the second multi-ribbed pulley; Insert the smaller diameter end of the rotary guide generator into the through cylindrical cavity for fixation, and let the smaller diameter end of the generator protrude from the other end. Axial locking is achieved by using the M25×1.5 external thread of the generator head to engage with the M25×1.5 internal thread of the generator locking sleeve. Start the variable frequency motor, drive the generator to rotate through the multi-ribbed belt, the first multi-ribbed pulley and the second multi-ribbed pulley, and drive the generator to rotate through the magnetic coupling of the magnet assembly; Multi-stage vibration absorption and isolation are achieved through a tolerance ring between the bearing housing and the bearing housing, a sealing ring between the bearing housing and the generator clamping housing, a fastener with an elastic pre-tightening element at the tail, a tapered elastic pad embedded in the wooden board platform, and a multi-wedge pulley assembly.

[0019] The beneficial effects of the embodiments of the present invention are: 1. In existing technologies, synchronous belt drives rely on the meshing of belt teeth and pulley teeth to transmit power. The teeth generate periodic impact noise during engagement and disengagement, and the axial arrangement of the teeth causes significant airflow disturbance during pulley rotation. This invention employs a transmission pair composed of a multi-wedge belt and a multi-wedge pulley. The multi-wedge belt has multiple circumferentially arranged annular wedge grooves that engage with corresponding annular wedge ribs on the pulley, transmitting power through wedge surface friction. This eliminates tooth surface meshing impact, resulting in smoother operation. This invention further optimizes the multi-wedge pulley tooth profile parameters: 40° rounded corner teeth, rounded corner R = 0.3mm, tooth depth 0.06±0.25mm, wedge spacing e = 2.34±0.03mm, and effective diameter de = 2.99±0.02mm. This specific tooth profile design ensures sufficient friction while reducing relative slippage and vibration excitation between the belt and pulley, thus reducing transmission noise at its source. 2. Multi-stage vibration reduction design for synergistic noise reduction: This invention incorporates vibration reduction elements at multiple key stages, forming a complete vibration energy absorption and isolation chain. Bearing-level vibration reduction: A tolerance ring is set between the bearing housing and the bearing housing, and its elastic deformation is used to absorb the high-frequency vibration generated by the bearing rotation, so as to avoid direct rigid collision between the bearing housing and the housing bore. Vibration damping at the connection level: A sealing ring with a compression of about 15% is set between the bearing housing and the generator clamping housing. At the same time, a screw with a helical spring at the end is used to fix the bearing housing with a wire diameter of 1mm, a mean diameter of 7mm, and a pitch of 2mm. The spring provides a constant preload and isolates the vibration transmission between the screw head and the housing. The sealing ring further blocks the vibration from propagating along the contact surface. Support-level vibration reduction: The damping feet use tapered elastic pads embedded in the wooden platform to achieve a non-rigid connection between the entire test device and the rigid platform, cutting off the path of vibration propagation to the ground; The above-mentioned three-stage vibration reduction combined with the low noise characteristics of multi-wedge belt drive makes the overall operating noise of the machine much lower than that of existing test benches using synchronous belt drive. 3. Improved accuracy in generator performance testing: Due to the significant reduction in operating noise, operators can clearly distinguish abnormal noises during generator operation, such as bearing damage, magnet scraping, and rotor imbalance, thereby accurately assessing the generator's quality status. Simultaneously, the multi-stage vibration reduction design effectively suppresses the interference of the testing device's own mechanical vibration on the generator's output electrical parameters, making the voltage, current, and power data collected by the power analyzer more accurate and stable, and avoiding changes in contact resistance or fluctuations in measurement signals caused by vibration. 4. Protecting the generator and extending equipment life: The tolerance ring prevents fretting wear between the bearing housing and the bearing bore, extending the life of the bearing and bearing housing; the sealing ring has both dustproof and vibration damping functions, protecting the bearing from dust intrusion; the spring preload screw provides continuous clamping force under vibration, preventing thread loosening and avoiding accidental damage due to connection failure; the tapered elastic pad's flexible contact with the wooden platform also prevents the test device from hard collision with the platform, protecting the outer shell and internal components. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the low-noise downhole generator testing device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the power generation clamping shell according to an embodiment of the present invention; Figure 3 This is a schematic cross-sectional view of the power generation clamping housing according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the test cross-section of the downhole generator after removing the generator locking sleeve and protective cover, according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the magnet structure according to an embodiment of the present invention; Figure 6 and 7 This is a schematic diagram of the bearing housing body structure according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the first multi-wedge pulley structure according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the second multi-wedge pulley and multi-wedge belt according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the wedge pulley tooth profile structure and parameters according to an embodiment of the present invention; Figure 11-12 This is a schematic diagram of the structure and parameters of the first multi-wedge pulley according to an embodiment of the present invention; Figure 13 This is a schematic diagram of the structure and parameters of the second multi-wedge pulley according to an embodiment of the present invention; Figure 14 This is a schematic diagram of the structure of the low-noise downhole generator testing device according to an embodiment of the present invention, with the generator locking sleeve and protective cover installed; Figure 15This is a schematic diagram of the structure of the generator locking sleeve according to an embodiment of the present invention; Figure 16 This is a schematic diagram of the protective cover structure according to an embodiment of the present invention; Icon: Generator clamping housing 1; Upper plane 101; Lower plane 102; Opening slot 103; First inner cavity 104; Second inner cavity 105; Tapered surface 106; First through hole 107; Transmission assembly 2; Variable frequency motor 210; First multi-ribbed pulley 220; Circular hole with radial rectangular groove 221; Second multi-ribbed pulley 230; Generator locking sleeve 240; Four-step cylindrical hole 241; Multi-ribbed belt 250; Shock-damping motor plate 260; Protective cover 270; Second through hole 271; Heat dissipation slot hole 272; Magnet assembly 3; Magnet 310; Magnetic strip groove 311; Magnetic strip 320; Magnet housing 330; Bearing assembly 4; First bearing 410; Second bearing 420; Bearing housing body 401; Bearing housing shell 402; Bearing 403; Assembly ring 404; First bolt hole 405; Second bolt hole 406; Connecting cylinder 407; Annular groove 408; Tolerance ring 409; Sealing ring 410; Fastener 411; Elastic preload element 412; 5. Vibration damping foot; 501. Vibration damping frame; 502. Vibration damping bolt; 503. Tapered elastic pad; 6. Wooden countertop; Test vehicle 7. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. 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, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0031] First Embodiment Please see Figure 1This embodiment provides a low-noise downhole generator testing device, including a generator clamping housing 1, a transmission assembly 2, a magnet assembly 3, a bearing assembly 4, and a shock-absorbing foot 5.

[0032] Please see Figure 2-3 The generator clamping housing 1 is a cylindrical structure with a through-type cylindrical inner cavity for accommodating the rotary guided downhole generator A; the upper plane 101 and the lower plane 102 are symmetrically cut out on the outer wall of the generator clamping housing 1.

[0033] Specifically, the outer wall of the generator clamping housing 1 is symmetrically cut with an upper plane 101 and a lower plane 102. The cut length of the upper / lower plane 102 is less than the length of the generator clamping housing 1, and the cut thickness is less than the thickness of the cylinder of the generator clamping housing 1. This makes one end of the generator clamping housing 1 have an annular cross-section, and the other end has an oval cross-section with a central circular hollow. This design of the upper and lower planes 102 provides a precise mounting reference surface for the frequency converter motor 210 and the vibration damping foot 5. On the other hand, it reduces the overall weight by locally thinning the material, while retaining sufficient structural strength at both ends of the cylinder.

[0034] An axially extending opening groove 103 is formed in the middle of the arc-shaped edge of the cylindrical wall with an oval cross-section. Specifically, an axially extending opening groove 103 is formed in the middle of the arc-shaped edge of the cylindrical wall with an oval cross-section. The opening groove 103 starts at the end face of the oval cross-section of the shell and extends into the shell. Its starting end is fan-shaped at the end face, and its ending end is cylindrical in the shell, with the diameter of the cylindrical hole being larger than the width of the opening groove 103. Overall, the cross-sectional shape of the opening groove 103 gradually narrows from a fan shape at the end face to a cylindrical hole.

[0035] The fan-shaped starting end provides a guiding surface when the generator is inserted, allowing the positioning protrusion on the generator housing to smoothly slide from the fan-shaped starting end into the cylindrical hole, avoiding jamming. The end of the cylindrical hole serves as the final positioning point, forming a limiting fit with the protrusion to achieve the assembly effect of "first guide, then lock".

[0036] The through-type cylindrical inner cavity includes a first inner cavity 104 and a second inner cavity 105. The first inner cavity 104 is located at the annular end and has a larger diameter than the second inner cavity 105. It is used to assemble key components with large radial dimensions, such as the magnet assembly 3 and the bearing assembly 4. The bottom of the second inner cavity 105 has a tapered surface 106. This tapered surface 106 gradually narrows from the inner wall of the second inner cavity 105 towards the edge of the first through hole, forming a funnel-shaped transition. This guides the smaller diameter end of the generator to be smoothly inserted, avoiding jamming or scratching caused by abrupt changes in hole diameter, reducing assembly difficulty, and protecting the generator surface and the inner cavity wall.

[0037] The first inner cavity 104 and the second inner cavity 105 are connected by a first through hole 107. The diameter of the first through hole 107 is smaller than the diameter of the second inner cavity 105. The first through hole 107 constrains the larger diameter end of the generator within the second inner cavity 105, while placing the smaller diameter end of the generator within the first inner cavity 104. This creates an annular stepped surface at the bottom of the second inner cavity 105, near the side closest to the first inner cavity 104. This surface forms a limiting fit with the shoulder of the generator or the end face of the magnet assembly 3 / bearing assembly 4. When the generator is inserted into place, the stepped surface prevents the generator from moving in the insertion direction during operation, ensuring that the axial position of the magnet assembly 3 and the bearing assembly 4 within the first inner cavity 104 remains constant.

[0038] During assembly, the smaller diameter end of the generator is inserted from the oval end, i.e., the side of the second inner cavity 105, and then passes through the second inner cavity 105 and the first through hole 107 before entering the first inner cavity 104.

[0039] Please see Figure 4 The magnet assembly 3 and bearing assembly 4 are sleeved on the outside of the smaller diameter end of the generator and housed within the first inner cavity 104. The smaller diameter end of the generator eventually protrudes from the magnet assembly 3, bearing assembly 4, and other structures, specifically: The magnet assembly 3 is assembled in the annular space formed between the outer wall of the generator and the inner wall of the generator clamping housing 1, and specifically includes a magnet 310, a magnetic strip 320 and a magnet housing 330.

[0040] Please see Figure 5 The magnet 310 is cylindrical and is fitted onto the outer wall of the smaller diameter end of the generator. The outer diameter of the magnet 310 is 55mm ± 0.005mm, and its outer wall has six magnetic strip grooves 311 arranged in a circular array along its circumference. The outer diameter of the magnet 310 is controlled within a high-precision range of 55mm ± 0.005mm to form a transition fit with the inner ring of the bearing, which ensures coaxiality during assembly and avoids stress concentration or assembly difficulties caused by excessive interference.

[0041] The magnetic strip 320 is a rounded elongated permanent magnet, which is embedded in six magnetic strip slots 311. The six circularly distributed magnetic strip slots 311, together with the corresponding number of magnetic strips 320, form a uniform magnetic pole pair in the circumferential direction, so that the generator rotor obtains a smooth electromagnetic torque when rotating, reduces the fluctuation of magnetic drag torque, and thus reduces electromagnetic vibration and noise.

[0042] The magnet housing 330 is a cylindrical sheath that is fitted over the magnet strip 320, encapsulating the magnet strip 320 within a sealed cavity between the magnet 310 and the magnet housing 330. This prevents the magnet strip 320 from falling off or being damaged by external forces during high-speed rotation. When the magnet housing 330 is made of a magnetically conductive material, it can serve as part of the magnetic circuit, reducing magnetic flux leakage; when it is made of a non-magnetically conductive material, it can shield against external magnetic field interference, improving the generator's output efficiency.

[0043] The bearing assembly 4 is also assembled within the annular space formed between the outer wall of the generator and the inner wall of the generator clamping housing 1, and is located on the outer ring of the magnet assembly 3, closely attached to the bottom wall of the generator clamping housing 1. The bearing assembly 4 includes a first bearing 410 and a second bearing 420 arranged sequentially along the axial direction. Each bearing is a deep groove ball bearing, model 16011, with the inner ring of the bearing having a transition fit with the outer wall of the magnet 310. The specific structure of the bearing assembly 4 is as follows; please refer to [link / reference]. Figure 6-7 : The bearing housing includes a bearing housing body 401 and a bearing housing shell 402. The bearing housing body 401 is used to fix the bearing 403, and the bearing housing shell 402 mates with the inner wall of the generator clamping housing 1. One end of the bearing housing body 401 extends outward in the expansion direction to form an assembly ring 404. The assembly ring 404 is provided with 7 bolt holes for fixing the bearing housing to the generator clamping housing 1 with fasteners. Four bolt holes, designated as first bolt holes 405, are located on one side of the assembly ring 404, with an angle of 30° to 45° between any two adjacent first bolt holes 405. The other three bolt holes, designated as second bolt holes 406, are located on the other side of the assembly ring 404, with an angle of 15° to 20° between any two adjacent second bolt holes 406. The angle between adjacent first bolt holes 405 and second bolt holes 406 is 65° to 105°. The seven bolt holes are distributed at an asymmetrical angle of 4+3, which breaks the modal resonance frequency that may be generated when the distribution is uniform. At the same time, it makes the fastening force more adaptable to the actual force distribution of the bearing housing. Bearing 403 mainly bears radial force, and the force is greater near the load side, thus avoiding excessive stress concentration around the bolt holes. The non-uniform distribution of the preload from the seven screws makes the connection stiffness between the bearing housing and the outer shell more uniform, reducing the additional vibration caused by local deformation.

[0044] The bearing 403 is fixedly mounted on the inner ring of the bearing housing body 401. The bearing housing body 401 extends upward (axially) from the outer ring of the bearing 403 into a connecting cylinder 407. One or more annular grooves 408 are provided on the cylinder wall of the connecting cylinder 407 to accommodate tolerance rings 409.

[0045] A tolerance ring 409 is provided on both the bearing housing body 401 and the bearing housing shell 402. The tolerance ring 409 is an open ring or a spiral ring made of elastic metal or polymer, and is assembled in the annular groove 408 of the connecting cylinder 407, so that the bearing housing shell 402 and the bearing housing body 401 form an elastic contact based on a clearance fit.

[0046] Specifically, the initial fit between the bearing housing 402 and the bearing body 401 is a clearance fit. After adding a tolerance ring 409 into the clearance, the tolerance ring 409 is slightly compressed, filling the gap and providing preload. While the clearance fit between the bearing housing 402 and the bearing housing facilitates assembly, it can generate relative fretting and impact at high speeds, resulting in high-frequency vibration noise. The tolerance ring 409 elastically fills the gap, radially preloading the bearing housing and eliminating free clearance, thereby suppressing collision and friction noise caused by the clearance. Furthermore, the tolerance ring 409 itself is elastic; when the bearing 403 vibrates radially, the tolerance ring 409 undergoes elastic deformation, converting vibration energy into internal energy dissipation, thus acting as a buffer and damper. The tolerance ring 409 can also automatically adapt to dimensional deviations between the bearing housing and the bearing housing, reducing the requirements for part machining accuracy while ensuring post-assembly stability.

[0047] A sealing ring 410 is provided between the bearing housing and the inner wall of the generator clamping housing 1. Specifically, a sealing ring 410 is arranged at the corresponding gaps between the first bearing 410 and the second bearing 420 and the inner wall of the generator clamping housing 1. The sealing ring 410 is designed with a compression of approximately 15%, which ensures both sealing effect and provides a certain vibration damping capacity. The sealing ring 410 is located between the bearing housing 402 and the generator clamping housing 1, and its 15% compression keeps it in an elastic compression state. When the bearing housing vibrates, the rubber elastomer of the sealing ring 410 absorbs part of the vibration energy, blocking the direct transmission of vibration from the bearing housing to the housing. In addition, the sealing ring 410 also serves to prevent dust and oil leakage, protect the internal grease of the bearing 403 from contamination, and extend the life of the bearing 403. The circumferential uniform compression force of the sealing ring 410 also helps to maintain the coaxiality between the bearing housing and the housing.

[0048] Fasteners 411 and elastic preload elements 412 are used to secure the bearing housing to the generator clamping housing 1. The bearing housing is fixedly connected to the generator clamping housing 1 via seven fasteners 411 with elastic preload elements 412 at their tails. The fasteners 411 are M5×12 socket head cap screws, and the elastic preload elements 412 are helical springs fitted onto the tails of the screws. The helical springs have a wire diameter of 1mm, a pitch diameter of 7mm, and a thread pitch of 2mm, and are made of spring steel. During assembly, the screws are screwed into the threaded holes of the generator clamping housing 1 through the bolt holes of the bearing housing. The helical springs are compressed between the screw head (or tail) and the bearing housing, providing a continuous axial preload force.

[0049] The first bearing 410 and the second bearing 420 are arranged axially to jointly bear the radial load and possible axial thrust of the generator rotor. Each bearing 403 is independently equipped with a tolerance ring 409 and a sealing ring 410, forming two independent vibration damping units, so that the vibration is gradually attenuated during axial transmission, and the noise reduction effect is better than the single bearing 403 scheme.

[0050] The synergistic effect of magnet assembly 3 and bearing assembly 4 includes: The precise transition fit between the outer diameter of the magnet 310 (55mm ± 0.005mm) and the inner ring of the bearing 403 ensures the concentricity of the magnet 310 and the inner ring of the bearing 403, while avoiding excessive assembly stress. This makes the rotor rotate smoothly and reduces the noise caused by magnetic pull imbalance due to eccentricity. Compact axial layout: The magnet assembly 3 is located in the middle of the annular space, and the bearing assembly 4 is located on the outer ring of the magnet assembly 3 (close to the bottom wall of the housing). The two overlap radially and are offset axially, making full use of the limited space. At the same time, vibration sources, such as the unbalanced magnetic force of the magnet assembly 3 and the rolling element impact of the bearing 403, are absorbed nearby by the tolerance ring 409 and the sealing ring 410.

[0051] Please see Figure 1 The transmission assembly 2 includes a variable frequency motor 210, a first multi-ribbed pulley 220, a second multi-ribbed pulley 230, a generator locking sleeve 240, and a multi-ribbed belt 250, with the following specific configuration: A variable frequency motor 210 is mounted on the upper surface 101 of the generator clamping housing 1. A vibration damping motor plate 260 is also provided between the variable frequency motor 210 and the generator clamping housing 1. This vibration damping motor plate 260 is made of an elastic material, such as rubber or polyurethane, and is used to absorb the high-frequency vibrations generated by the motor itself, as well as to adjust its thickness during the commissioning of the multi-ribbed belt drive pair. The variable frequency motor 210 itself generates electromagnetic vibration and fan airflow noise during operation. The vibration damping motor plate 260 flexibly isolates the motor from the generator clamping housing 1, blocking the direct transmission of motor vibration to the housing and preventing the housing from becoming a noise radiation surface.

[0052] Please see Figure 8 The first multi-ribbed pulley 220 is connected to the output shaft of the variable frequency motor 210. The output shaft of the variable frequency motor 210 has a flat key, which cooperates with the keyway in the hub of the first multi-ribbed pulley 220 to realize torque transmission.

[0053] The first multi-wedge pulley 220 has a circular hole 221 with a radial rectangular groove in its center. Specifically, the circular hole has a diameter of 19mm, and a rectangular groove extends radially outward from its circumference. The width of the rectangular groove along the circumference (i.e., the length of the groove along the tangent) is 6mm, and the radial depth is 2.5mm, making the distance from the outer side of the rectangular groove (the side furthest from the center) to the farthest point opposite the circular hole 21.5mm. This irregularly shaped hole is used to mate with a positioning boss or anti-rotation structure on the motor shaft end to prevent the pulley from slipping on the shaft. Compared to the ordinary method of tightening a set screw with a circular hole, this structure can transmit torque without additional fasteners 411 and avoids vibration and noise caused by loose set screws. This irregularly shaped hole also allows the axial position of the pulley on the shaft to be precisely defined by a shaft shoulder or retaining ring, ensuring the alignment of the two pulleys and reducing belt misalignment noise caused by skewing.

[0054] Please see Figure 9 The second multi-ribbed pulley 230 is the driven pulley and is fixed to the magnet housing 330 of the magnet assembly 3. The multi-ribbed belt 250 connects the first multi-ribbed pulley 220 and the second multi-ribbed pulley 230, forming a transmission pair. The second multi-ribbed pulley 230 is fixed to the magnet housing 330 by a locking sleeve, rather than being directly fixed to the generator shaft. This design decouples the rotational mass of the transmission system from the generator rotor: the rotating components driven by the multi-ribbed belt 250 are the magnet housing 330 and the magnet assembly 3, while the generator rotor rotates under magnetic coupling, with no rigid connection between them. Therefore, the vibration of the transmission belt is not directly transmitted to the generator rotor, further reducing the vibration noise at the generator output.

[0055] The second multi-ribbed pulley 230 is fixed to the magnet housing 330, rather than directly to the generator shaft. This design decouples the rotational mass of the transmission system from the generator rotor: the rotating components driven by the multi-ribbed belt 250 are the magnet housing 330 and the magnet assembly 3, while the generator rotor rotates under magnetic coupling, with no rigid connection between them. Therefore, the vibration of the transmission belt is not directly transmitted to the generator rotor, further reducing vibration noise at the generator output.

[0056] Please see Figure 10-13 The multi-ribbed belt 250 connects the first multi-ribbed pulley 220 and the second multi-ribbed pulley 230, forming a transmission pair. The transmission ratio is 1:1, both pulleys have an outer diameter of 67.5mm, and the center distance is 134mm. The 1:1 transmission ratio ensures that the generator speed matches the variable frequency motor 210 speed, eliminating the need for speed calculations and facilitating control and measurement. The 67.5mm outer diameter and 134mm center distance design ensures a sufficiently large pulley wrap angle to prevent slippage and also makes the overall structure compact. The identical outer diameter of the two pulleys facilitates machining and inventory management.

[0057] The first multi-wedge pulley 220 and the second multi-wedge pulley 230 adopt the same annular multi-wedge belt 250 gear tooth profile, namely, annular wedge grooves arranged circumferentially. Specific tooth parameters are as follows: tooth angle: 40° rounded corner; tooth tip radius: R=0.3mm; tooth groove depth: 0.06±0.25mm; wedge spacing / center distance between adjacent wedge grooves: e=2.34±0.03mm; effective diameter: d e =2.99±0.02mm. The above parameters were designed with reference to the national standard JB / T 5983-1992 and optimized for low noise requirements.

[0058] Compared to V-belt drives: Conventional V-belt drives rely on friction between the belt side and the pulley grooves. During operation, the belt's expansion and contraction, slippage, and compression during wedging into and out of the pulley grooves generate significant low-to-mid-frequency noise. This invention redesigns a new multi-wedge belt 250, which has multiple circumferentially arranged annular wedge ribs that form multi-line contact with the corresponding annular wedge grooves on the pulley. This results in a large contact area, low unit pressure, smooth operation, and significantly lower friction noise compared to V-belts.

[0059] Compared to synchronous belt drives, synchronous belts have teeth arranged axially, generating periodic tooth surface impact noise during meshing, and at high speeds, the engagement / disengagement of the teeth causes axial vibration of the pulley. The multi-wedge belt of this invention, with a 250mm tooth surface meshing impact, transmits power through wedge friction, and its noise source characteristics are continuous friction rather than pulsed impact, resulting in lower high-frequency noise.

[0060] Optimized tooth profile parameters, such as 40° rounded teeth, R=0.3mm rounded corner, and 0.06mm shallow tooth depth, reduce belt bending stress and extrusion deformation during wedging while ensuring sufficient friction, further reducing operating noise.

[0061] Please see Figure 14-15 The generator locking sleeve 240 has four stepped cylindrical holes 241 inside, which are four cylindrical hole segments arranged sequentially along the axial direction with gradually changing diameters. These holes are used to fit and lock the smaller diameter end of the generator, thereby achieving axial fastening of the generator housing, magnet assembly 3, bearing assembly 4, etc. The smaller diameter end of the generator is inserted into the oval cross-section end of the generator clamping housing 1 and extends to the outside of the annular cross-section end. The magnet assembly 3, bearing assembly 4, and transmission assembly 2 are sequentially fitted / assembled on the smaller diameter end of the generator and are housed together in the annular space between the outer wall of the generator and the inner wall of the generator clamping housing 1, and fastened using the generator locking sleeve 240.

[0062] The testing device is also equipped with a protective cover 270 to cover the transmission pair, serving to provide safety protection, noise reduction, and dust prevention. Please refer to [link / reference needed]. Figure 16 The specific structure is as follows: Overall Shape: The protective cover 270 has a groove structure, and its bottom outer contour is a double-centered waist shape formed by the line connecting two collinear arcs (a large circle and a small circle) and their common tangent point. A second through hole 271 is provided at the bottom of the protective cover 270 for the generator locking sleeve 240 to pass through, allowing the locking sleeve to connect to or extend outside the cover. The protective cover 270 completely covers the entire transmission pair consisting of the first multi-ribbed pulley 220, the second multi-ribbed pulley 230, and the multi-ribbed belt 250. The protective cover 270 is detachably fixed to the generator clamping housing 1 by bolts. Three vertically extending heat dissipation slots 272 or louvered heat dissipation holes are provided on the side wall or back of the protective cover 270 to dissipate the heat generated by the operation of the transmission component 2, preventing excessive temperature rise from affecting the lifespan of the multi-ribbed belt 250.

[0063] The shock-absorbing foot 5 is installed on the lower surface 102 of the generator clamping housing 1. The lower end of the shock-absorbing foot 5 is provided with a tapered elastic pad for embedding into the test platform, so that the generator clamping housing 1, the generator locking sleeve 240, the second multi-wedge pulley 230 have no contact with the test platform. The shock-absorbing foot 5 also includes a shock-absorbing frame 501 and a shock-absorbing bolt 502. The upper part of the shock-absorbing frame 501 is connected to the lower plane 102 of the generator clamping housing 1 through the shock-absorbing bolt 502. The tapered elastic pad 503 is disposed on the bottom outer wall of the shock-absorbing frame 501, and the outer diameter of the tapered elastic pad 503 gradually decreases from top to bottom.

[0064] This invention also provides a low-noise downhole generator test bench, including the test device of any of the foregoing, and a wooden platform 6; the tapered elastic pad 503 of the shock-absorbing foot 5 of the test device is embedded in the wooden platform 6 or in direct contact with the wooden platform 6, so that a non-rigid connection is formed between the test device and the wooden platform 6.

[0065] This embodiment also provides a low-noise downhole generator test vehicle 7, including the aforementioned test platform and multiple casters mounted under the wooden platform 6. The casters are swivel casters or directional casters with brakes. The low-noise downhole generator test vehicle 7 in this embodiment has three layers: upper, middle, and lower, with the test device mounted on the middle layer. A towing handle is also provided on the frame.

[0066] This invention also provides a method for testing a low-noise downhole generator, using any of the aforementioned testing devices, or the aforementioned test bench, or the aforementioned test vehicle 7, comprising the following steps: The magnet assembly 3 and the bearing assembly 4 are sequentially assembled onto the generator clamping housing 1, so that the magnet assembly 3 and the bearing assembly 4 are located in the annular space formed by the outer wall of the generator and the inner wall of the generator clamping housing 1. When assembling the bearing assembly 4, a tolerance ring 409 is placed between each bearing housing and the bearing housing, and a sealing ring 410 is pressed between the bearing housing and the inner wall of the generator clamping housing 1. The bearing housing is fixed to the generator clamping housing 1 by a screw with a helical spring at the end. The elastic deformation of the helical spring provides a constant preload and absorbs high-frequency vibration. The tapered elastic pad 503 at the lower end of the shock-absorbing foot 5 is embedded into the wooden platform 6, so that the entire test device forms a non-rigid contact with the wooden platform 6, so as to avoid the generator and the test device directly contacting the rigid platform; the variable frequency motor 210 of the transmission component 2 is assembled onto the upper plane 101 of the generator clamping housing 1, and the first multi-ribbed pulley 220 is assembled on the variable frequency motor 210; the second multi-ribbed pulley 230 is assembled on the generator locking sleeve 240, and the multi-ribbed belt 250 connects the first multi-ribbed pulley 220 and the second multi-ribbed pulley 230; The smaller diameter end of the downhole generator is inserted into the through-cylindrical cavity for fixation, allowing the smaller diameter end of the generator to protrude from the other end. Axial locking is achieved by engaging the M25×1.5 external thread of the generator head with the M25×1.5 internal thread of the generator locking sleeve 240. The downhole generator head has a built-in dual-core connector, and the tail is equipped with a seven-core slip ring connector. The entire test device does not obstruct the front and rear ends of the generator, meaning the generator passes through the test device, allowing the head and tail of the generator to protrude outside the test device. Sufficient installation space has been reserved in the structural design stage for electrical plug-in and matching connectors, facilitating rapid electrical performance testing. This fixing method uses single-point locking of the generator head, with no additional clamping constraints on the body. The generator clamping cylinder 1 adopts a thin-walled cylindrical structure, which can ensure good heat dissipation conditions for the generator during long-term testing and solve the problems of poor heat dissipation and easy overheating failure caused by clamping the generator body in traditional test benches, greatly improving the accuracy and operational reliability of generator testing. Adjusting the tension of the wedge pulley: After assembling the generator, it is necessary to ensure that the tension of the wedge pulley is moderate. After multiple adjustments and optimizations, it was determined that the optimal tension is achieved by applying pressure vertically at the midpoint of the slack side of the belt, with the deflection controlled at 1% to 2% of the center distance between the two pulleys. The center distance between the two pulleys on this test bench is 134mm. In actual assembly, the optimal tension is achieved when the belt can be pressed down 3 to 4mm by pressing the middle section with the thumb. This effectively avoids problems such as slippage and excessive vibration caused by an overly loose belt, and high rotational resistance and bearing overheating caused by an overly tight belt. The belt tension can be flexibly adjusted by machining a thinner vibration damping motor plate or by adding shims. This structure adopts a split design, making height adjustment and belt tension adjustment convenient and reliable. It eliminates the need for complex adjustment mechanisms such as tension pulleys and idler pulleys, simplifying the overall structure and reducing the difficulty of assembly and adjustment. Start the variable frequency motor 210, drive the generator to rotate through the multi-wedge belt 250, the first multi-wedge pulley 220 and the second multi-wedge pulley 230, and drive the generator to rotate through the magnetic coupling of the magnet assembly 3; Multi-stage vibration absorption and isolation are achieved through a tolerance ring 409 between the bearing housing and the bearing housing, a sealing ring 410 between the bearing housing and the generator clamping housing 1, a fastener 411 with an elastic pre-tightening element 412 at the tail, a tapered elastic pad 503 embedded in the wooden board platform 6, and a multi-wedge belt 250 wheel set.

[0067] By testing the generator's output voltage range at different speeds, its electrical performance can be preliminarily determined. A 24-hour continuous load endurance test at 4500 r / min is then conducted. Before the test ends, abnormal noises from the generator are listened to to assess the coaxiality and installation reliability of the internal bearings and stator / rotor systems. If abnormal noises are detected, the assembly is deemed unqualified and reworked. This structure can clearly distinguish subtle abnormal noises under low-noise conditions, effectively avoiding problems such as qualified output voltage but abnormal internal wear and failures shortly after being installed in the well due to coaxiality deviations. It also significantly reduces the operating noise of the test bench, improving the working environment for operators.

[0068] In summary, the embodiments of the present invention achieve the above objectives through the following technical means: Reduce transmission system noise: By replacing the V-belt or synchronous belt in the existing technology with a self-designed low-noise multi-wedge belt drive pair and optimizing the pulley tooth profile parameters, the friction and impact noise generated during the transmission process is reduced from the source; Achieving multi-level vibration isolation and absorption: By introducing tolerance rings, sealing rings, and fasteners with elastic preload springs at the tail of the bearing assembly, the bearing fit clearance is eliminated and the vibration transmission path is blocked; at the same time, a vibration damping motor plate is set between the motor and the housing, and a tapered elastic pad embedded in the wooden board platform 6 is set at the bottom to construct a complete vibration damping link from the vibration source such as the motor and bearings to the housing and then to the base platform. Optimize the layout and fixation of key components: Utilize the variable diameter inner cavity of the generator clamping housing. The first inner cavity accommodates the magnet assembly and bearing assembly, while the second inner cavity guides and the stepped hole design of the generator locking sleeve ensures the coaxiality and stable locking of the generator, magnet assembly and bearing assembly, avoiding additional vibration caused by assembly eccentricity or loosening. Improved testing accuracy and operational comfort: By significantly reducing the operating noise of the device itself, subtle abnormal noises from the generator, such as bearing damage and magnet scraping, can be clearly identified, thereby improving the accuracy of performance evaluation; at the same time, it provides a quiet working environment for operators.

[0069] In summary, the present invention aims to provide a specialized testing equipment for downhole generators that is compact in structure, operates smoothly, and has significantly lower noise than existing test benches. It is particularly suitable for new factory testing and post-maintenance quality assessment of noise-sensitive rotary steering downhole generators.

[0070] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-noise downhole generator testing device, characterized in that, include: The generator clamping housing is a cylindrical structure with a through-type cylindrical inner cavity for accommodating a rotary steerable downhole generator; the outer wall of the generator clamping housing is symmetrically cut with an upper plane and a lower plane; The transmission assembly includes a variable frequency motor, a first multi-ribbed pulley, a second multi-ribbed pulley, a generator locking sleeve, and a multi-ribbed belt. The variable frequency motor is mounted on the upper surface of the generator clamping housing. The first multi-ribbed pulley is connected to the output shaft of the variable frequency motor. The second multi-ribbed pulley is fixed relative to the generator clamping housing via a magnet assembly. The multi-ribbed belt connects the first multi-ribbed pulley and the second multi-ribbed pulley to form a transmission pair. The magnet assembly is assembled within the annular space formed between the outer wall of the generator and the inner wall of the generator clamping housing; A bearing assembly is assembled within the annular space and located on the outer ring of the magnet assembly. The bearing assembly includes a bearing housing, a bearing installed within the bearing housing, a tolerance ring disposed between the bearing housing housing and the bearing housing, and a sealing ring disposed between the bearing housing and the inner wall of the generator clamping housing. The bearing housing is fixedly connected to the generator clamping housing by a fastener with an elastic preload element at the tail. The shock-absorbing foot is installed on the lower surface of the generator clamping housing. The lower end of the shock-absorbing foot is provided with a tapered elastic pad for embedding into the test platform, so that the generator clamping housing, the generator locking sleeve, the second multi-wedge pulley and the test platform are not in contact. The smaller diameter end of the generator is inserted into the oval cross-section end of the generator clamping housing and extends to the outside of the annular cross-section end; the magnet assembly and bearing assembly are sequentially sleeved on the smaller diameter end of the generator and are together housed in the annular space between the outer wall of the generator and the inner wall of the generator clamping housing, and are fastened using a generator locking sleeve.

2. The low-noise downhole generator testing device according to claim 1, characterized in that, The outer wall of the generator clamping shell is symmetrically cut with an upper and lower plane. The cut length of the upper / lower plane is less than the length of the generator clamping shell, and the cut thickness is less than the thickness of the generator clamping shell cylinder. This makes one end of the generator clamping shell have an annular cross-section, and the other end has an oval cross-section with a central circular hollow. An axially extending opening groove is formed in the middle of the arc-shaped edge of the oval cross-section cylinder wall. The through-type cylindrical inner cavity includes a first inner cavity and a second inner cavity. The first inner cavity is located at the annular end and has a diameter greater than that of the second inner cavity. The first inner cavity and the second inner cavity are connected by a first through hole, the diameter of which is smaller than that of the second inner cavity. The bottom of the second inner cavity has a tapered surface.

3. The low-noise downhole generator testing device according to claim 1, characterized in that, The first and second multi-wedge pulleys use the same annular wedge pulley tooth profile, which is a 40° rounded corner tooth with a radius R = 0.3 mm and a rounded corner tooth depth of 0.06 ± 0.25 mm; the wedge spacing e = 2.34 ± 0.03 mm and the effective diameter de = 2.99 ± 0.02 mm.

4. The low-noise downhole generator testing device according to claim 1, characterized in that, The outer diameters of the first and second multi-wedge pulleys are both 67.5 mm, and the center distance is 134 mm. The transmission ratio of the transmission assembly is 1:

1. The first multi-wedge pulley has a circular hole with a radial rectangular groove in its center. The circular hole has a diameter of 19 mm, and a rectangular groove extends radially outward from its circumferential edge. The width of the rectangular groove is 6 mm along the circumferential direction, and the radial depth is 2.5 mm, so that the distance from the outer side of the rectangular groove (i.e., the side away from the center) to the farthest point opposite the circular hole is 21.5 mm. The second multi-wedge pulley has a circular through hole with a diameter of 55 mm in its center.

5. The low-noise downhole generator testing device according to claim 1, characterized in that, The magnet assembly includes a magnet, a magnetic strip, and a magnet housing. The magnet is sleeved on the outer wall of the generator, the magnetic strip is sleeved on the outside of the magnet, and the magnet housing is sleeved on the outside of the magnetic strip, so that the magnetic strip is encapsulated in the annular cavity formed by the generator outer wall, the magnet, and the magnet housing.

6. The low-noise downhole generator testing device according to claim 1, characterized in that, The bearing assembly includes a first bearing and a second bearing arranged sequentially along the axial direction, and a tolerance ring is provided between the outer ring of each bearing and the corresponding bearing housing.

7. The low-noise downhole generator testing device according to claim 1, characterized in that, The fastener with an elastic preload element at the tail is a screw, and the elastic preload element is a helical spring sleeved on the tail of the screw. The helical spring has a wire diameter of 1mm, a mean diameter of 7mm, and a pitch of 2mm.

8. The low-noise downhole generator testing device according to claim 1, characterized in that, The shock-absorbing foot also includes a shock-absorbing frame and shock-absorbing bolts. The upper part of the shock-absorbing frame is connected to the lower plane of the generator clamping housing through the shock-absorbing bolts. The tapered elastic pad is set on the bottom outer wall of the shock-absorbing frame, and the outer diameter of the tapered elastic pad gradually decreases from top to bottom.

9. A low-noise downhole generator test bench, characterized in that, The test device includes the test apparatus according to any one of claims 1-8, and a wooden tabletop; the tapered elastic pads of the shock-absorbing feet of the test device are embedded in or in direct contact with the wooden tabletop, so that a non-rigid connection is formed between the test device and the wooden tabletop.

10. A low-noise downhole generator test vehicle, characterized in that, It includes the test platform as described in claim 9, and a plurality of casters installed under the wooden platform, wherein the casters are swivel casters or directional casters with brakes.

11. A testing method for a low-noise downhole generator, characterized in that, Using the testing apparatus according to any one of claims 1-8, or the testing bench according to claim 9, or the testing vehicle according to claim 10, includes the following steps: The magnet assembly and bearing assembly are sequentially assembled onto the generator clamping housing. When assembling the bearing assembly, a tolerance ring is placed between each bearing housing and the bearing housing, and a sealing ring is pressed between the bearing housing and the inner wall of the generator clamping housing. The bearing housing is fixed to the generator clamping housing using screws with helical springs at the tail. The elastic deformation of the helical springs provides a constant preload and absorbs high-frequency vibrations. The tapered elastic pad at the bottom of the shock-absorbing foot is embedded in the wooden platform, so that the entire test device forms a non-rigid contact with the wooden platform, thereby avoiding direct contact between the generator and the test device and the rigid platform; the variable frequency motor of the transmission component is assembled onto the upper plane of the generator clamping shell, and the first multi-wedge pulley is assembled on the variable frequency motor; the second multi-wedge pulley is assembled on the generator locking sleeve, and the multi-wedge belt connects the first multi-wedge pulley and the second multi-wedge pulley; Insert the smaller diameter end of the rotary guide generator into the through cylindrical cavity for fixation, and let the smaller diameter end of the generator protrude from the other end. Axial locking is achieved by using the M25×1.5 external thread of the generator head to engage with the M25×1.5 internal thread of the generator locking sleeve. Start the variable frequency motor, drive the generator to rotate through the multi-ribbed belt, the first multi-ribbed pulley and the second multi-ribbed pulley, and drive the generator to rotate through the magnetic coupling of the magnet assembly; Multi-stage vibration absorption and isolation are achieved through a tolerance ring between the bearing housing and the bearing housing, a sealing ring between the bearing housing and the generator clamping housing, a fastener with an elastic pre-tightening element at the tail, a tapered elastic pad embedded in the wooden board platform, and a multi-wedge pulley assembly.

Images