Clearance-controllable retainer and frictional resistance measuring method thereof

Abstract

The invention discloses a gap-controllable retainer and a frictional resistance measuring method thereof, belongs to the technical field of mechanical equipment manufacturing, and solves the problem that an existing device can only test a retainer with a fixed gap and cannot simulate the influence of dynamic gap change on bearing performance. The retainer capable of controlling the gap comprises a retainer body capable of adjusting the gap between the retainer body and a rolling body, a retainer moving assembly and a gap adjusting part. The gap adjusting part comprises an adjusting motor, an eccentric wheel and a motor fixing frame. According to the retainer capable of controlling the gap, the gap between the retainer and a rolling body can be dynamically adjusted, the retainer can be matched with different types of ball-disc testing machines (rotary type and linear contact type) for friction resistance measurement, the gap between the rolling body and a pocket of the retainer can be flexibly adjusted by adjusting the motor and the eccentric wheel, and the friction resistance of the rolling body is measured. And therefore, the retainer main body can meet the retaining and limiting requirements of different working conditions and different types of bearings, and the performance, the service life and the reliability of the bearings are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical equipment manufacturing, and in particular relates to a retaining frame with controllable clearance and a method for measuring friction resistance thereof. Background Art

[0002] The cage of a rolling bearing is a crucial component of the bearing, separating and guiding the rolling elements to prevent collisions. It also ensures that the rolling elements are evenly distributed between the inner and outer rings of the bearing. This determines the optimal condition of the rolling bearing and is susceptible to factors such as the cage's geometry, material properties, and pocket clearance. Understanding the impact of cage pocket clearance is crucial for the operational efficiency and development of both mechanical equipment and rolling bearings.

[0003] Currently, most cage model testing studies use fixed pocket clearances, which are unable to adapt to the dynamic demands of varying operating conditions, such as high speeds, heavy loads, or temperature fluctuations. Fixed clearance designs can easily lead to increased collision and friction between the rolling elements and the cage at high speeds, causing vibration, noise, and temperature rise. Furthermore, under heavy loads or extreme temperatures, fixed clearances can lead to stress concentration or thermal expansion problems, reducing bearing reliability and life.

[0004] Under high-speed operation, centrifugal force causes rolling elements to deflect toward the outer ring, increasing the contact force between the rolling elements and the cage. Fixed clearances cannot effectively reflect these dynamic changes, leading to collisions between the rolling elements and the cage, resulting in additional friction and energy loss. Furthermore, because fixed clearances cannot effectively absorb the dynamic impact of high-speed operation, collisions between the rolling elements and the cage can cause vibration and produce noticeable noise. This vibration and noise not only affect the smooth operation of the equipment but can also disrupt the surrounding environment. Under heavy loads, the loads borne by the rolling elements increase significantly. Fixed clearance designs can lead to uneven contact stress distribution between the rolling elements and the cage, exacerbating localized stress concentrations and reducing the strength and durability of the cage. The cage may undergo elastic or plastic deformation due to the restrictions of the fixed clearance, causing pocket shape changes and further increasing friction and wear between the rolling elements and the cage. Over long-term operation, this wear can significantly shorten the bearing's service life. Furthermore, the fixed clearance cannot be dynamically adjusted based on load changes, resulting in uneven load distribution between the rolling elements. Some rolling elements may bear excessive loads, while others fail to fully utilize their load-bearing capacity, reducing the bearing's overall load-bearing efficiency. Furthermore, under temperature fluctuations, bearing components (including the cage and rolling elements) undergo dimensional changes due to thermal expansion and contraction. The fixed clearance design cannot adapt to this thermal expansion effect, resulting in the clearance being too small at high temperatures or too large at low temperatures, thus affecting the proper operation of the bearing. If the clearance is too small at high temperatures, it can lead to severe sticking, increasing friction, continuously rising temperatures, and, in severe cases, bearing failure. If the clearance is too large at low temperatures, it can cause the rolling elements to wobble within the pockets, increasing vibration and noise while reducing the bearing's positioning accuracy.

[0005] In the study of bearing cages, existing experimental devices and research methods, while capable of simulating bearing operating conditions to a certain extent, still have limitations. Some methods, designed to test the friction coefficient and wear performance between the cage and rolling elements, typically employ reciprocating or rotational motion to simulate bearing motion. However, these methods cannot fully simulate dynamic friction behavior at high speeds, heavy loads, or extreme temperatures, and they struggle to monitor the effects of clearance changes on friction in real time. Other methods, designed to test the dynamic performance of cages under high-speed operation, can only test cages with fixed clearances and cannot dynamically adjust the clearance to accommodate varying speeds or loads. Other methods, designed to simulate the thermal expansion effects of bearings under extreme temperatures, employ heating or cooling devices. However, these methods struggle to precisely control the clearance changes between the cage and rolling elements, and they cannot adjust the clearance in real time to compensate for thermal expansion. In summary, most existing devices can only test cages with fixed clearances and cannot simulate the effects of dynamic clearance changes on bearing performance. To overcome the limitations of existing research devices and meet the higher requirements for bearing performance in modern industry, we propose a cage with controllable clearance and a friction resistance measurement method. By dynamically adjusting the gap between the cage and the rolling elements, it can adapt to the needs of different working conditions (such as high speed, heavy load, high temperature), thereby significantly improving the performance, life and reliability of the bearing. Summary of the Invention

[0006] The purpose of the present invention is to address the shortcomings of the existing technology and provide a cage with controllable clearance and a method for measuring the friction resistance thereof, which solves the problem that the existing device can only test cages with fixed clearance and cannot simulate the impact of dynamic clearance changes on bearing performance.

[0007] The present invention is achieved by providing a cage with controllable clearance, the cage comprising: A cage body with adjustable clearance to the rolling elements; The retainer moving assembly is provided on the displacement platform and is connected to the retainer body, and is used to support and move the retainer body; A gap adjustment part is provided on one side of the displacement platform, and the gap adjustment part is used to drive the retainer body and the retainer moving assembly; The gap adjustment part includes an adjustment motor, an eccentric wheel and a motor fixing frame. The adjustment motor is installed on the motor fixing frame. The external fixed sleeve of the drive shaft of the adjustment motor is provided with an eccentric wheel, and the eccentric wheel is arranged corresponding to the retaining frame moving component.

[0008] Preferably, the retainer body comprises: A retainer seat, the retainer seat being mounted on the retainer moving assembly; A cage pocket is provided in the cage seat, and an adjustable gap is formed between the cage pocket and the rolling element.

[0009] Preferably, an L-shaped plate is provided on one side of the displacement platform, and the displacement platform and the L-shaped plate are connected by a plate fixing bolt. A seat fixing bolt is provided at the end of the displacement platform, and the seat fixing bolt is used to prevent the displacement platform from shaking during testing. A multi-axis drive platform is provided in the displacement platform, and the multi-axis drive platform is used to adjust the horizontal and vertical positions of the displacement platform.

[0010] Preferably, the retainer moving assembly includes: The measuring sensor is connected to the cage seat and is used to collect the bidirectional pressure between the cage pocket and the rolling element in real time, and convert the pressure signal into an electrical signal to record the change state of the friction force in real time; a dovetail groove fixedly connected to the measuring sensor, the dovetail groove being arranged corresponding to the eccentric wheel; A groove guide rail, which is fixedly mounted on the upper surface of the displacement platform and is slidably connected to the dovetail groove, and is used to guide and limit the dovetail groove; At least one set of return springs, the return springs are used to control the return of the dovetail groove and assist the eccentric wheel in controlling and adjusting the gap between the pocket and the rolling element; At least one set of spring fixing bolts, the spring fixing bolts are fixedly assembled on the displacement platform, the spring fixing bolts are fixedly connected to one end of the return spring, and one end of the return spring away from the spring fixing bolts is fixedly connected to the dovetail groove.

[0011] Preferably, the measuring sensor is a tension and compression sensor, and the measuring range of the measuring sensor is 5N.

[0012] Preferably, the rolling body is a test steel ball, and the diameter of the test steel ball is 5.4 mm. The diameter ratio of the rolling body to the cage pocket is 1:1.08. The cage seat is made of resin 8000. The rolling body can be detachably mounted on the servo motor. A ball-disc testing machine is provided on one side of the rolling body. The contact test bench of the ball-disc testing machine is in contact with the rolling body, and the surface of the contact test bench is coated with grease. The contact test bench is a rotating contact test bench or a line contact test bench.

[0013] Preferably, the length of the return spring including the hook is 15 mm, the outer diameter is 2 mm, and the wire diameter is 0.2 mm.

[0014] On the other hand, the present invention also provides a method for measuring the friction resistance of a cage, the method comprising: S10, test preparation stage, using petroleum ether and anhydrous ethanol to clean the surfaces of the rolling elements and the cage pockets in sequence, adjusting the height of the cage seat to align with the center height of the rolling elements using a multi-axis drive platform, injecting lithium-based grease into the cage pockets, and adjusting the clearance between the rolling elements and the cage pockets using the multi-axis drive platform in coordination with the adjustment motor; S20. Before the test begins, use petroleum ether and anhydrous ethanol to clean the surfaces of the contact test bench, rolling elements, and cage pockets. Grease is evenly applied to the track of the contact test bench using a syringe and a grease scraper at a speed of 2.0 mm / s. Then, install the controllable clearance cage, and use a multi-axis drive platform to adjust the height of the cage seat to align with the center height of the rolling elements. The clearance between the rolling elements and the cage pockets is adjusted by adjusting the motor. S30, turn on the servo motor, which drives the rolling element to rotate. After the rolling element rotates 10 times, its surface is completely covered with grease. Then, the speed of the ball-on-disc testing machine is increased to the speed set for the test. The test data of rolling friction, sliding friction and oil film formation are collected through measuring sensors and high-speed cameras. Among them, the measuring sensor collects the two-way pressure between the cage pocket and the rolling element in real time, and converts the pressure signal into an electrical signal, and records the change state of the friction force in real time.

[0015] Preferably, when the gap between the rolling element and the cage pocket is adjusted by the adjusting motor, the adjusting motor is turned on, the adjusting motor starts to drive the eccentric wheel to rotate, and the eccentric wheel drives the dovetail groove to slide along the groove guide rail, so that the dovetail groove drives the cage seat and the cage pocket to move, thereby realizing the adjustment of the gap between the rolling element and the cage pocket; during the test stage, the moving distance, speed and time of the dovetail groove are captured by a high-speed camera, so as to obtain the actual experimental distance between the cage pocket and the rolling element.

[0016] Compared with the prior art, the embodiments of the present application have the following beneficial effects: The controllable clearance retainer provided by the present invention can dynamically adjust the clearance between the retainer and the rolling element, and can cooperate with different types of ball-on-disc testing machines (rotational type, line contact type) to measure friction resistance. By adjusting the motor and the eccentric wheel, the clearance between the rolling element and the retainer pocket can be flexibly adjusted, thereby enabling the retainer body to adapt to the retention and limiting requirements of different working conditions and different types of bearings, significantly improving the performance, life and reliability of the bearing.

[0017] In the embodiment of the present invention, the provision of the gap adjustment portion can, on the one hand, achieve flexible adjustment of the gap between the rolling element and the cage pocket; on the other hand, by adjusting the motor and the eccentric wheel linkage, the gap between the rolling element and the cage pocket can be cyclically adjusted, thereby enabling the cage with controllable gap to play multiple roles of better support, guidance, protection and friction reduction during movement, and also ensuring the performance, life and reliability of the bearing.

[0018] In an embodiment of the present invention, the clearance between the rolling element and the cage pocket can be dynamically adjusted according to the working conditions through the coordinated cooperation of the clearance adjustment part and the cage moving assembly, thereby improving the performance and life of the bearing. In addition, when the clearance is automatically adjusted, the clearance can be automatically adjusted through the cooperation of the measuring sensor and the control system, thereby reducing manual intervention and improving the intelligence level of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of a gap-controllable retaining frame provided by the present invention.

[0020] Figure 2 The graph shows the change of friction force over time when the eccentric distance of the eccentric wheel is 1 mm.

[0021] Figure 3 The graph shows the change of friction force over time when the eccentric distance of the eccentric wheel is 1.5 mm.

[0022] Figure 4 The graph shows the change of friction force over time when the eccentric distance of the eccentric wheel is 2 mm.

[0023] Figure 5 Test results are shown for a rolling element speed of 256.0 mm / s and a pocket height of 15.0 mm.

[0024] Figure 6 A test diagram showing the range of changes in the distance of different eccentric wheels over time is shown.

[0025] Figure 7 A schematic diagram of the retainer main structure during the cylindrical roller-disc line contact test bench test is shown.

[0026] In the figure: 1-cage body, 11-cage seat, 12-cage pocket, 2-cage moving assembly, 21-measuring sensor, 22-dovetail groove, 23-groove guide, 24-reset spring, 25-spring fixing bolt, 3-gap adjustment part, 31-adjusting motor, 32-motor fixing frame, 33-eccentric wheel, 4-displacement platform, 41-L-type plate, 42-plate fixing bolt, 43-seat fixing bolt, 44-multi-axis drive platform, 5-rolling element. DETAILED DESCRIPTION

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0028] Most existing devices can only test cages with fixed clearances and are unable to simulate the effects of dynamic clearance changes on bearing performance. To overcome the limitations of existing research devices and meet the higher requirements of modern industry for bearing performance, we have proposed a cage with controllable clearance and a method for measuring its friction resistance. By dynamically adjusting the clearance between the cage and the rolling elements 5, the requirements of different operating conditions (such as high speed, heavy load, and high temperature) can be met, thereby significantly improving the performance, lifespan, and reliability of the bearing. In short, the controllable clearance cage consists of a cage body 1 with an adjustable clearance from the rolling elements 5, a cage moving assembly 2, and a clearance adjustment unit 3. The clearance adjustment unit 3 includes an adjustment motor 31, an eccentric wheel 33, and a motor mounting bracket 32. The controllable clearance retainer provided by the present invention can dynamically adjust the clearance between itself and the rolling element 5, and can cooperate with different types of ball-on-disc testing machines (rotational, line contact) to measure friction resistance. Moreover, by adjusting the motor 31 and the eccentric wheel 33, the clearance between the rolling element 5 and the retainer pocket 12 can be flexibly adjusted, thereby enabling the retainer body 1 to adapt to different working conditions and the retention and limiting requirements of different types of bearings, thereby significantly improving the performance, life and reliability of the bearings.

[0029] Example 1

[0030] The embodiment of the present invention provides a retaining frame with controllable clearance, such as Figure 1 As shown, the retaining frame with controllable clearance specifically includes: A retainer body 1 having an adjustable gap with the rolling element 5; The cage moving assembly 2 is provided on the displacement platform 4 and is connected to the cage body 1 for supporting and moving the cage body 1; The gap adjustment part 3 is provided on one side of the displacement platform 4 and is used to drive the retainer body 1 and the retainer moving assembly 2; Among them, the gap adjustment part 3 includes an adjustment motor 31, an eccentric wheel 33 and a motor fixing frame 32. The adjustment motor 31 is installed on the motor fixing frame 32. The external fixed sleeve of the drive shaft of the adjustment motor 31 is provided with an eccentric wheel 33. The eccentric wheel 33 is arranged corresponding to the retaining frame moving component 2. At the same time, the adjustment motor 31 is connected to the motor fixing frame 32 through a screw. The motor fixing frame 32 is fixedly assembled under the contact test bench of the ball-disc testing machine by means of a clip or bolt connection. The height of the adjustment motor 31 and the eccentric wheel 33 can be adjusted by the screw so that the eccentric wheel 33 adapts to the retaining frame moving component. 2. Height adjustment. In the embodiment of the present invention, the provision of the gap adjustment portion 3 enables flexible adjustment of the gap between the rolling element 5 and the cage pocket 12. Furthermore, the gap between the rolling element 5 and the cage pocket 12 can be cyclically adjusted by the linkage of the adjustment motor 31 and the eccentric wheel 33. This allows the cage with controllable gap to better support, guide, protect, and reduce friction during movement, thereby ensuring the performance, life, and reliability of the bearing. The adjustment motor 31 has an operating voltage of 12V, a speed of 60 rpm, a power of 15W, and a shaft diameter of 8mm.

[0031] In this embodiment, the eccentric wheel 33 is hollow inside, and is fixedly connected to the drive shaft of the regulating motor 31 by interference fit or snap connection. The large circle radius of the eccentric wheel 33 is 6 mm, the small circle radius is 4 mm, and the eccentric distance is 2 mm.

[0032] The controllable clearance retainer provided by the present invention can dynamically adjust the clearance between itself and the rolling element 5, and can cooperate with different types of ball-on-disc testing machines (rotational, line contact) to measure friction resistance. Moreover, by adjusting the motor 31 and the eccentric wheel 33, the clearance between the rolling element 5 and the retainer pocket 12 can be flexibly adjusted, thereby enabling the retainer body 1 to adapt to different working conditions and the retention and limiting requirements of different types of bearings, thereby significantly improving the performance, life and reliability of the bearings.

[0033] In a further preferred embodiment of the present invention, Figure 1 As shown, the retainer body 1 includes: A cage seat 11, wherein the cage seat 11 is mounted on the cage moving assembly 2; A cage pocket 12 is formed in the cage seat 11 , and an adjustable gap is formed between the cage pocket 12 and the rolling element 5 .

[0034] In this embodiment, the cage seat 11 is a rectangular seat or a round seat, and the cage pocket 12 is a circular groove structure. The rolling element 5 can be a spherical bearing, a cylindrical roller, a needle roller, a tapered roller or a spherical roller.

[0035] In the embodiment of the present invention, an L-shaped plate 41 is provided on one side of the displacement platform 4. The displacement platform 4 and the L-shaped plate 41 are connected by plate fixing bolts 42. A seat fixing bolt 43 is provided at the end of the displacement platform 4. The seat fixing bolt 43 is used to prevent the displacement platform 4 from shaking during testing. A multi-axis drive platform 44 is provided inside the displacement platform 4. The multi-axis drive platform 44 is used to adjust the horizontal and vertical positions of the displacement platform 4. The displacement platform 4 can be set in front of, behind, on the left or right side of the rolling element 5 and work in conjunction with the contact test bench of the ball-disc testing machine, so that the retainer seat 11 can adapt to the simulation test requirements under different working conditions. The multi-axis drive platform 44 can be a mutually coordinated X-, Y-, and Z-axis displacement drive platform, so that the retainer with controllable clearance in this embodiment can be flexibly adjusted in position. The X-, Y-, and Z-axis displacement drive platforms can be pneumatic cylinders or oil cylinders with an accuracy of 0.03mm. The displacement platform 4 is made of steel.

[0036] In a further preferred embodiment of the present invention, Figure 1 As shown, the retainer moving assembly 2 includes: The measuring sensor 21 is connected to the cage seat 11 and is used to collect the bidirectional pressure between the cage pocket 12 and the rolling element 5 in real time, convert the pressure signal into an electrical signal, and record the change state of the friction force in real time. The measuring sensor 21 is a tension and compression sensor with a measuring range of 5N. A dovetail groove 22 fixedly connected to the measuring sensor 21, the dovetail groove 22 being arranged corresponding to the eccentric wheel 33; The groove guide rail 23 is fixedly mounted on the upper surface of the displacement platform 4 and is slidably connected to the dovetail groove 22. The groove guide rail 23 is used to guide and limit the dovetail groove 22. The setting of the dovetail groove 22 can reduce the bottom of the movement of the retainer body 1. At the same time, the eccentric wheel 33 moves the dovetail groove 22 under the drive of the adjustment motor 31. After the dovetail groove 22 moves forward a certain distance, it is pulled back by the return spring 24, and the cycle is repeated, thereby realizing a retainer structure with controllable clearance; At least one set of return springs 24, which are used to control the return of the dovetail groove 22 and assist the eccentric wheel 33 in controlling the gap between the pocket and the rolling element 5. The return spring 24 has a hook length of 15 mm, an outer diameter of 2 mm, and a wire diameter of 0.2 mm. At least one set of spring fixing bolts 25 is fixedly assembled on the displacement platform 4 , and the spring fixing bolts 25 are fixedly connected to one end of the return spring 24 , and the end of the return spring 24 away from the spring fixing bolts 25 is fixedly connected to the dovetail groove 22 .

[0037] In this embodiment, the rolling body 5 is a test steel ball, and the diameter of the test steel ball is 5.4 mm. The test steel ball meets the G5 precision standard. The diameter ratio of the rolling body 5 and the cage pocket 12 is 1:1.08. The cage seat 11 is made of resin 8000. The rolling body 5 can be detachably mounted on the servo motor. A ball-disc testing machine is provided on one side of the rolling body 5. The contact test bench of the ball-disc testing machine is in contact with the rolling body 5, and the surface of the contact test bench is coated with grease. The contact test bench is a rotating contact test bench or a line contact test bench.

[0038] In the embodiment of the present invention, the clearance between the rolling element 5 and the cage pocket 12 can be dynamically adjusted according to the working conditions through the coordinated cooperation of the clearance adjustment unit 3 and the cage moving assembly 2, thereby improving the performance and life of the bearing. In addition, when the clearance is automatically adjusted, the clearance can be automatically adjusted through the cooperation of the measuring sensor 21 and the control system, thereby reducing manual intervention and improving the intelligence level of the bearing. To verify the feasibility of its method, the embodiment of the present invention uses a ball-disc point contact / line contact testing machine for method verification and testing. The present invention is also applicable to a cylindrical roller-disc line contact test bench. When the cylindrical roller-disc line contact test bench is tested, the shape of the corresponding cage body 1 also changes accordingly. Figure 7 The figure shows the main structure diagram of the cage during the cylindrical roller-disc line contact test bench test, where: Figure 7 The rolling element 5 is a cylindrical roller.

[0039] Example 2

[0040] The present invention also provides a method for measuring the friction resistance of a cage. The method can be verified and tested using a conventional ball-on-disc point contact / line contact testing machine. The method for measuring the friction resistance of a cage specifically includes: S10, test preparation stage: The surfaces of the rolling element 5 and the cage pocket 12 are cleaned with petroleum ether and anhydrous ethanol in sequence, and then blown dry with nitrogen to ensure the contact surfaces are clean. The height of the cage seat 11 is adjusted to align with the center height of the rolling element 5 by the multi-axis drive platform 44. Lithium-based grease is injected into the cage pocket 12. The clearance between the rolling element 5 and the cage pocket 12 is adjusted by the multi-axis drive platform 44 in coordination with the adjustment motor 31. Specifically, when injecting lithium-based grease into the retaining frame pocket 12, a syringe is used to inject 2.0 g of lithium-based grease. At the same time, the eccentric wheel 33 is connected to the adjusting motor 31 to control the speed of the adjusting motor 31 and thus the speed of the eccentric wheel 33. The motor fixing frame 32 can adjust the height of the adjusting motor 31. During adjustment, the eccentric wheel 33 is required to reach the upper end of the dovetail groove 22. At the same time, the distance, speed and time of the dovetail groove 22 moving forward and backward can be photographed with the help of a high-speed camera to obtain the actual experimental distance of the retaining frame.

[0041] In order to explore the influence of the gap between the rolling element 5 and the cage pocket 12, the friction force of the eccentric wheel 33 with different eccentricities of 1 mm, 1.5 mm, and 2 mm was measured in this embodiment. Figure 2 The graph shows the variation of friction force over time when the eccentric distance of the eccentric wheel 33 is 1 mm. Figure 3 The curve showing the change of friction force over time when the eccentric distance of the eccentric wheel 33 is 1.5 mm is shown. Figure 4 The curve showing the change of friction force over time when the eccentric distance of the eccentric wheel 33 is 2 mm is shown. On the other hand, this embodiment measures the friction force under different gap conditions. Figure 5 The test results for rolling element 5 with a speed of 256.0 mm / s and a pocket height of 15.0 mm are given, where: Figure 5 In the example, the fixed gap between the cage and the rolling element 5 is 0.2 mm, where Figure 2-4 It can be seen that the curve of friction force changing with time for different gaps shows that when the eccentricity of the eccentric wheel 33 is 1mm, the gap between the cage and the rolling element 5 varies from 0.2 to 1.2. It can be clearly seen that when the cage is closest to the rolling element 5, the friction coefficient is large and the shear friction is correspondingly the largest. As the gap gradually increases, the friction coefficient decreases and the shear friction decreases. When the gap exceeds 1mm, the friction force is 0 because the gap is large enough. Under the same conditions, when the eccentricity of the eccentric wheel 33 is 1.5 and 2mm, the gap range also increases, and the time for the friction force to go from maximum to 0 increases, but the time for the friction force to remain at 0 decreases. Figure 5 It can be seen that the friction force varies significantly with different gaps. When the gap is small, the oil film thickness is low, the friction coefficient is large, and the shear friction is correspondingly large. As the gap gradually increases, the lubricating oil film thickness increases, the friction coefficient decreases, and the shear friction decreases accordingly.

[0042] S20. Before the test begins, use petroleum ether and anhydrous ethanol to clean the contact test bench, rolling element 5, and cage pocket 12 surfaces. Grease is evenly applied to the contact test bench rails using a syringe and a grease scraper at a speed of 2.0 mm / s. The controllable-gap cage is then installed, and the height of the cage seat 11 is adjusted to align with the center height of the rolling element 5 using the multi-axis drive platform 44. The gap between the rolling element 5 and the cage pocket 12 is adjusted using the motor 31, and the height is adjusted using the multi-axis drive platform 44 to ensure that the cage's geometric center is aligned with the center of the rolling element 5. Simultaneously, the dovetail groove 22 is adjusted to change the cage's position, maintaining an appropriate gap between the pocket surface and the rolling element 5 surface. In the embodiment of the present invention, the mass of the grease is 2.0 g, the base oil of the grease used in the test is polyalphaolefin (PAO), and the thickener is a lithium-based material.

[0043] S30, turning on the servo motor, which drives the rolling element 5 to rotate. After the rolling element 5 rotates 10 times, its surface is completely covered with grease. Then, the speed of the ball-on-disc tester is increased to the test set speed. The test data of rolling friction, sliding friction, and oil film formation are collected by the measuring sensor 21 and the high-speed camera. The measuring sensor 21 collects the bidirectional pressure between the cage pocket 12 and the rolling element 5 in real time, converts the pressure signal into an electrical signal, and records the change state of the friction force in real time. Figure 6 A test diagram showing the range of variation of the distance of different eccentric wheels 33 over time is shown.

[0044] In this embodiment, when the gap between the rolling element 5 and the retainer pocket 12 is adjusted by the adjusting motor 31, the adjusting motor 31 is turned on, and the adjusting motor 31 starts to drive the eccentric wheel 33 to rotate, and the eccentric wheel 33 drives the dovetail groove 22 to slide along the groove guide rail 23, so that the dovetail groove 22 drives the retainer seat 11 and the retainer pocket 12 to move, thereby realizing the adjustment of the gap between the rolling element 5 and the retainer pocket 12; during the test stage, the moving distance, speed and time of the dovetail groove 22 are captured by a high-speed camera to obtain the actual experimental distance between the retainer pocket 12 and the rolling element 5.

[0045] In summary, the present invention provides a retaining frame with controllable clearance and a method for measuring friction resistance thereof. The retaining frame with controllable clearance provided by the present invention can dynamically adjust the clearance between the retaining frame and the rolling element 5, and can cooperate with different types of ball-disc testing machines (rotational, line contact) to measure friction resistance. Moreover, by adjusting the motor 31 and the eccentric wheel 33, the clearance between the rolling element 5 and the retaining frame pocket 12 can be flexibly adjusted, thereby enabling the retaining frame body 1 to adapt to different working conditions and the retention and limiting requirements of different types of bearings, thereby significantly improving the performance, life and reliability of the bearings.

[0046] It should be noted that for the aforementioned embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also fall within the scope of protection of the present invention.

Claims

1. A cage with controllable clearance, characterized in that: The cage with controllable clearance includes: A cage body with adjustable clearance to the rolling elements; The retainer moving assembly is provided on the displacement platform and is connected to the retainer body, and is used to support and move the retainer body; A gap adjustment part is provided on one side of the displacement platform, and the gap adjustment part is used to drive the retainer body and the retainer moving assembly; The gap adjustment part includes an adjustment motor, an eccentric wheel and a motor fixing frame. The adjustment motor is installed on the motor fixing frame. The outer fixed sleeve of the drive shaft of the adjustment motor is provided with an eccentric wheel, and the eccentric wheel is arranged corresponding to the movable component of the retaining frame. The cage moving assembly includes: The measuring sensor is connected to the cage seat and is used to collect the bidirectional pressure between the cage pocket and the rolling element in real time, and convert the pressure signal into an electrical signal to record the change state of the friction force in real time; a dovetail groove fixedly connected to the measuring sensor, the dovetail groove being arranged corresponding to the eccentric wheel; A groove guide rail, which is fixedly mounted on the upper surface of the displacement platform and is slidably connected to the dovetail groove, and is used to guide and limit the dovetail groove; At least one set of return springs, the return springs are used to control the return of the dovetail groove and assist the eccentric wheel in controlling and adjusting the gap between the pocket and the rolling element; At least one set of spring fixing bolts, the spring fixing bolts are fixedly assembled on the displacement platform, the spring fixing bolts are fixedly connected to one end of the return spring, and one end of the return spring away from the spring fixing bolts is fixedly connected to the dovetail groove.

2. The gap-controllable retainer according to claim 1, wherein: The retainer body comprises: A retainer seat, the retainer seat being mounted on the retainer moving assembly; A cage pocket is provided in the cage seat, and an adjustable gap is formed between the cage pocket and the rolling element.

3. The gap-controllable retainer according to claim 1, wherein: An L-shaped plate is provided on one side of the displacement platform, and the displacement platform and the L-shaped plate are connected by a plate fixing bolt. A seat fixing bolt is provided at the end of the displacement platform, and the seat fixing bolt is used to prevent the displacement platform from shaking during testing. A multi-axis drive platform is provided in the displacement platform, and the multi-axis drive platform is used to adjust the horizontal and vertical positions of the displacement platform.

4. The gap-controllable retainer according to claim 2, wherein: The measuring sensor is a tension and compression sensor, and the measuring range of the measuring sensor is 5N.

5. The gap-controllable retainer according to claim 4, wherein: The rolling element is a test steel ball with a diameter of 5.4 mm. The diameter ratio of the rolling element to the cage pocket is 1:1.

08. The cage seat is made of resin 8000. The rolling element can be detachably mounted on the servo motor. A ball-on-disc testing machine is provided on one side of the rolling element. The contact test bench of the ball-on-disc testing machine contacts the rolling element, and the surface of the contact test bench is coated with grease. The contact test bench is a rotating contact test bench or a linear contact test bench.

6. The gap-controllable retainer according to claim 5, wherein: The length of the return spring including the hook is 15 mm, the outer diameter is 2 mm, and the wire diameter is 0.2 mm.

7. A method for measuring the friction resistance of a cage with controllable clearance according to any one of claims 1 to 6, characterized in that: include: S10, test preparation stage, using petroleum ether and anhydrous ethanol to clean the surfaces of the rolling elements and the cage pockets in sequence, adjusting the height of the cage seat to align with the center height of the rolling elements using a multi-axis drive platform, injecting lithium-based grease into the cage pockets, and adjusting the clearance between the rolling elements and the cage pockets using the multi-axis drive platform in coordination with the adjustment motor; S20. Before the test begins, use petroleum ether and anhydrous ethanol to clean the surfaces of the contact test bench, rolling elements, and cage pockets. Grease is evenly applied to the track of the contact test bench using a syringe and a grease scraper at a speed of 2.0 mm / s. Then, install the controllable clearance cage, and use a multi-axis drive platform to adjust the height of the cage seat to align with the center height of the rolling elements. The clearance between the rolling elements and the cage pockets is adjusted by adjusting the motor. S30, turn on the servo motor, which drives the rolling element to rotate. After the rolling element rotates 10 times, its surface is completely covered with grease. Then, the speed of the ball-on-disc testing machine is increased to the speed set for the test. The test data of rolling friction, sliding friction and oil film formation are collected through measuring sensors and high-speed cameras. Among them, the measuring sensor collects the two-way pressure between the cage pocket and the rolling element in real time, and converts the pressure signal into an electrical signal, and records the change state of the friction force in real time.

8. The method for measuring the friction resistance of a retainer according to claim 7, wherein: When the gap between the rolling element and the cage pocket is adjusted by the adjusting motor, the adjusting motor is turned on, the adjusting motor starts to drive the eccentric wheel to rotate, and the eccentric wheel drives the dovetail groove to slide along the groove guide rail, so that the dovetail groove drives the cage seat and the cage pocket to move, thereby adjusting the gap between the rolling element and the cage pocket; during the test stage, the moving distance, speed and time of the dovetail groove are captured by a high-speed camera to obtain the actual experimental distance between the cage pocket and the rolling element.

Images