Spur gear ultrasonic impact gradient nano-strengthening device and method

Abstract

The application relates to a face gear ultrasonic impact gradient nanometer strengthening device, which comprises a driving device, an ultrasonic strengthening device and a directional ultrasonic strengthening chamber. The driving device comprises a motor, a time relay and a rotating shaft, the rotating shaft is used for mounting a face gear to be processed, the motor is connected with the rotating shaft, the time relay is connected with the motor, and the time relay is used for controlling the power-on / off time of the motor to control the rotation of the face gear at a specified angle. The ultrasonic strengthening device works alternately with the time relay. The directional ultrasonic strengthening chamber is arranged between the face gear and the ultrasonic strengthening device and comprises a first base, the upper end of the first base is provided with a first tooth sealing raceway, a second tooth sealing raceway and a tooth top protection cover plate, M impact through holes with sizes matched with the tooth surface of the face gear are arranged on the tooth top protection cover plate, and the cover plate between adjacent impact through holes is a tooth top protection part with a size matched with the tooth top of the face gear. The modules exposed to the medium hitting range are protected through the modular design, and directional strengthening is realized.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic impact fatigue-resistant manufacturing technology, specifically to a device and method for localized directional ultrasonic strengthening of irregularly shaped gear surfaces. Background Technology

[0002] Gears are a symbol of industrialization. Gears are essential for any mechanical equipment that transmits or transforms motion. Gears are a crucial and widely used fundamental component of mechanical equipment, determining its main functions, service life, and reliability. Their primary failure mode is fatigue (tooth root bending fatigue and tooth surface contact fatigue). Fatigue fracture of gear teeth generally occurs at the tooth root because the root has the highest stress and concentration. Furthermore, the tooth root is subjected to repeated bending stress after being loaded. When the alternating stress at the tooth root transition fillet exceeds the fatigue limit, fatigue cracks will appear. These cracks propagate continuously, eventually causing sudden breakage at the tooth root. After being loaded, the tooth surface will generate cyclically changing contact stress. Under repeated contact stress, cracks will initiate in the subsurface or surface layer of the tooth. The propagation of fatigue cracks causes spalling and pitting on the tooth surface, a condition known as surface contact fatigue failure, which typically occurs near the pitch line. Fatigue-resistant manufacturing is the foundation and guarantee for long-life transmission gears. Fatigue-resistant manufacturing is an advanced manufacturing technology that uses fatigue performance as the primary criterion and improves fatigue strength. It is a basic manufacturing technology that aims to ensure that manufactured components match the design performance, and it is also a typical high-efficiency, low-emission, and green environmental protection technology.

[0003] Ultrasonic impact strengthening requires a specific worktable and pulsed coupling time control to achieve directional strengthening of face gears. An ultrasonic impact nozzle is mounted below the worktable. When the generator starts working, the energy of the ultrasonic energy field is transferred to the workpiece surface through a medium, causing a modified strengthening layer with high surface strength and high core toughness, featuring a gradient nanostructure and work hardening, to form a fixed area on the face gear surface. The gradient nanostructure meets all the requirements for fatigue-resistant manufacturing. Currently, although various methods utilize ultrasonic energy fields to strengthen partial surfaces of workpieces, the gear tooth tip, tooth surface, and tooth root are exposed to the impact of the medium. This results in several drawbacks: the powerful impact energy can easily cause microcracks in the weak tooth tip, leading to a counterproductive effect; in some devices, the gear rotates continuously and is constantly impacted by the medium, making it impossible to guarantee the different strengthening requirements of different parts of the workpiece; furthermore, the gear clamping frame is also impacted simultaneously, requiring frequent replacement of the clamping device, significantly increasing costs and reducing strengthening efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art, such as microcracks caused by medium impact on the tooth tip, different strengthening requirements of different parts of the gear, and frequent replacement of clamping devices. The invention provides a surface gear ultrasonic impact gradient nano-strengthening device and method, which protects specific areas and achieves directional strengthening by modularly designing modules exposed to the medium impact range.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] An ultrasonic impact gradient nano-strengthening device for face gears includes a drive device for driving the face gear to rotate, an ultrasonic strengthening device, and a directional ultrasonic strengthening chamber.

[0007] The driving device includes a motor, a time relay, and a rotating shaft. The rotating shaft is used to fix the face gear to be processed. The output shaft of the motor is connected to the rotating shaft, driving the rotating shaft to drive the face gear to rotate synchronously. The time relay is connected to the motor and is used to control the power-on / power-off time of the motor to control the rotation of the face gear at a specified angle, exposing the tooth root and tooth surface of the specified strengthening area within the strengthening range of the directional ultrasonic strengthening chamber. The ultrasonic strengthening device is located below the face gear and is used to perform ultrasonic impact gradient nano-strengthening treatment on the face gear. The ultrasonic strengthening device and the time relay work alternately. When the ultrasonic strengthening device is working, the motor is de-energized; when the motor is energized, the ultrasonic strengthening device stops working.

[0008] The directional ultrasonic strengthening chamber is disposed between the face gear and the ultrasonic strengthening device. The directional ultrasonic strengthening chamber includes a first base, on which a through hole for accommodating the ultrasonic shot peening chamber is opened. The upper end of the first base is detachably installed with a first gear tooth sealing raceway, a second gear tooth sealing raceway, and a tooth tip protective cover plate. The first gear tooth sealing raceway and the second gear tooth sealing raceway are respectively tightly disposed on both sides of the tooth tip protective cover plate. The tooth tip protective cover plate has M impact through holes with sizes adapted to the face gear tooth surface, M≥1. The impact through holes are the strengthening range of the directional ultrasonic strengthening chamber. When M>1, the cover plate between adjacent impact through holes is a tooth tip protection part with a size adapted to the tooth tip of the face gear.

[0009] In the above scheme, let the motor output speed be n, where n ranges from 0 to 1000 rpm. The time required to rotate a unit angle is:

[0010]

[0011] Therefore, the time required for one gear tooth to turn can be calculated:

[0012]

[0013] In the formula, N is the total number of teeth on the face gear;

[0014] The number of gear teeth processed simultaneously by the ultrasonic strengthening device is M. The energizing time of the time relay is set to T1 = Mt; the de-energizing time of the time relay is the ultrasonic shock treatment time T2, and the range of T2 is 1s to 1200s.

[0015] In the above scheme, the ultrasonic strengthening device includes an ultrasonic shot peening chamber, an ultrasonic probe, and a small ball. The ultrasonic shot peening chamber has openings at both the upper and lower ends. The ultrasonic probe extends into the ultrasonic shot peening chamber from the lower opening. The small ball is placed on the ultrasonic probe and covers the upper surface of the ultrasonic probe. The upper opening of the ultrasonic shot peening chamber is placed at the lower end of the gear on the surface to be machined, and a clearance fit is achieved.

[0016] In the above scheme, the device further includes a continuous ultrasonic strengthening chamber, which is used to replace the directional ultrasonic strengthening chamber when no protection is required for the tooth tip.

[0017] In the above scheme, the continuous ultrasonic enhancement chamber includes a second base, on which a through hole is provided for accommodating the ultrasonic shot peening chamber. A pin sliding column is symmetrically installed on both sides of the through hole. A spring and a sealing pin are sequentially sleeved on the pin sliding column from bottom to top. The top of the sealing pin is designed as a toothed pin that meshes with the teeth of a face gear. Under the action of the spring's rebound force, the face gear is always tightly fitted with the continuous ultrasonic enhancement chamber during rotation, preventing the small ball from being splashed out during impact.

[0018] In the above scheme, the upper end of the first base is provided with sliding grooves on both sides, and the first gear tooth sealing raceway, the second gear tooth sealing raceway, and the tooth top protective cover plate are respectively provided with sliding parts that are adapted to the sliding grooves. The sliding parts are interference-fitted with the sliding grooves and slide to the designated reinforcement area.

[0019] In the above scheme, the upper part of the rotating shaft is connected to the motor, and the lower part of the rotating shaft is threaded to form a fixed gear screw. The face gear is installed on the fixed gear screw, and the upper and lower ends of the face gear are respectively provided with screw nuts for adjusting the position of the fixed face gear.

[0020] In the above scheme, the driving device also includes two clamping cover plates, which are fastened to both sides of the face gear by lead screw nuts at the upper and lower ends of the face gear.

[0021] In the above scheme, the strengthening device also includes a test bench, which includes an upper support and a lower support. The motor is installed above the upper support, the gear to be processed and the directional ultrasonic strengthening chamber are installed between the upper support and the lower support, and the ultrasonic strengthening device is installed below the lower support.

[0022] Accordingly, this invention also proposes a method for ultrasonic impact gradient nano-strengthening of face gears, which uses the aforementioned ultrasonic impact gradient nano-strengthening device for face gears to perform localized directional ultrasonic impact gradient nano-strengthening of face gears, including the following steps:

[0023] S1. Install the drive unit and the directional ultrasonic enhancement chamber above the ultrasonic probe, and make sure that the impact through hole of the tooth top protective cover plate is aligned with the ultrasonic shot peening chamber.

[0024] S2. Set the energizing time of the time relay so that the face gear rotates M teeth each time, and the time relay starts to run. At this time, be careful not to turn on the ultrasonic strengthening device.

[0025] S3. After the time relay completes one cycle, i.e., after rotating M tooth roots and surfaces, immediately turn on the ultrasonic strengthening device. At this time, the time relay is de-energized, the face gear is stationary, the designated area is exposed within the strengthening range, and the strengthening begins.

[0026] S4. After the enhancement is completed, the ultrasonic enhancement device stops, the time relay is energized, and it rotates M teeth to stop; this process is repeated to complete the directional area enhancement through time coupling between the time relay and the ultrasonic enhancement device until the enhancement is complete.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. This invention uses a time relay to control the opening and closing time of a motor, which is coupled with the opening and closing time of an ultrasonic generator. Combined with a specially designed directional ultrasonic strengthening chamber, this achieves uniform and stable gradient structure fabrication on the directional areas (i.e., tooth roots and tooth surfaces) of the workpiece surface, while protecting specific areas (i.e., tooth tips), thus realizing directional strengthening. High-frequency ultrasonic signals are used to excite small balls to impact the directional areas of the face gear. The energy of the small balls causes severe plastic deformation at the tooth roots and surfaces, leading to increased dislocation density, grain refinement, and the formation of a nano-reinforcing layer. This improves the surface hardness, wear resistance, and fatigue life of the face gear, breaking through the existing performance and life limits of aerospace face gears and achieving fatigue-resistant manufacturing of aerospace face gears.

[0029] 2. The directional ultrasonic strengthening chamber of this invention adopts a modular and detachable design, making the device for protecting the tooth tip easy to replace. It can strengthen face gears of different sizes at the lowest cost. At the same time, tooth tip protective covers with different structural forms (number of impact through holes) can be designed according to strengthening requirements, improving the applicability of the device. The tooth sealing raceways on both sides of the tooth tip protective cover not only restrict the sliding of the tooth tip protective cover, but also play a sealing role, preventing the small ball from escaping during strengthening, and further improving processing efficiency.

[0030] 3. The present invention also designs a continuous ultrasonic strengthening chamber, which is suitable for situations where some face gears do not have special requirements for the tooth tip and more attention is paid to processing efficiency and overall surface quality. Without changing the other components, only the ultrasonic strengthening chamber needs to be replaced, and there is no need to set a time relay, thus further improving the applicability of the device.

[0031] 4. The continuous ultrasonic strengthening chamber of this invention exposes the entire gear tooth within the chamber. Small balls continuously strike the teeth. Adjusting the ultrasonic generator power to a lower level and the motor speed to a higher level helps prevent micro-cracks at the tooth tips. After strengthening, the surface quality of the gear is better, and overall rust removal is achieved, reducing processing steps. During ultrasonic treatment, the spring's rebound force keeps the sealing pin engaged with the gear, preventing the small balls from splashing out during impact, thus improving safety and processing efficiency.

[0032] 5. The present invention has a nut screw formed by threading the lower end of the rotating shaft. The position of the upper and lower fixed face gears of the nut screw is adjustable, and the distance between the face gears and the upper end face of the ultrasonic shot peening cavity can be precisely adjusted to achieve adjustable process parameters.

[0033] 6. In gear failure modes, the tooth tip mainly fails due to microcracks, while the tooth surface and root fail due to spalling and pitting, resulting in root bending fatigue. The tooth tip, tooth surface, and tooth root require different strengthening frequencies due to their different morphologies and locations. If single-direction strengthening is inefficient, a method of continuous followed by directional strengthening can be adopted to address the gear strengthening problem. This provides high-efficiency and precise strengthening to meet the requirements. Specifically, in continuous operation, a uniform low frequency is used to only meet the strengthening requirements of the tooth tip, while the tooth surface and tooth root require directional strengthening by increasing the strengthening frequency to meet the overall gear strengthening needs.

[0034] 7. This invention is applicable to gears of various sizes and materials, such as aluminum alloys, titanium alloys, stainless steel, nickel-based alloys, and carbon steel. This ultrasonic impact surface nano-strengthening technology can be extended to the surface nano-strengthening and service life improvement of other mechanical components such as thrust bearings, blades, and turbine disks. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0036] Figure 1 This is a schematic diagram of the structure of the ultrasonic impact gradient nano-reinforcement device for face gears of the present invention when using a directional ultrasonic reinforcement chamber;

[0037] Figure 2 yes Figure 1 The main view;

[0038] Figure 3 This is a schematic diagram of the structure of a directional ultrasound enhancement chamber in one embodiment of the present invention;

[0039] Figure 4yes Figure 3 The diagram shown is an exploded view of the directional ultrasound enhancement chamber.

[0040] Figure 5 This is a schematic diagram of the tooth top protective cover plate of the directional ultrasonic enhancement chamber in another embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the structure of the ultrasonic impact gradient nano-reinforcement device for surface gears of the present invention when a continuous ultrasonic reinforcement chamber is used;

[0042] Figure 7 yes Figure 6 The main view;

[0043] Figure 8 This is a schematic diagram of the structure of a continuous ultrasound enhancement chamber in one embodiment of the present invention;

[0044] Figure 9 yes Figure 8 The diagram shows an exploded view of the continuous ultrasound enhancement chamber.

[0045] In the diagram: 10. Drive unit; 11. Motor; 12. Time relay; 13. Rotating shaft; 131. Fixed gear screw; 14. Thrust bearing; 15. Screw nut; 16. Clamping cover plate;

[0046] 20. Ultrasonic enhancement device; 22. Ultrasonic probe;

[0047] 30. Directional ultrasonic enhancement chamber; 31. First base; 311. Slide groove; 32. First gear tooth sealing raceway; 33. Second gear tooth sealing raceway; 34. Tooth top protective cover plate; 341. Impact through hole; 342. Tooth top protection part;

[0048] 40. Continuous ultrasound enhancement chamber; 41. Second base; 42. Ejector pin sliding column; 43. Spring; 44. Sealing ejector pin;

[0049] 50. Face gear;

[0050] 60. Test bench; 61. Upper support; 62. Lower support. Detailed Implementation

[0051] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0052] like Figure 1-2 As shown, an ultrasonic impact gradient nano-strengthening device for a face gear provided in an embodiment of the present invention includes a driving device 10 for driving the face gear to rotate, an ultrasonic strengthening device 20, and a directional ultrasonic strengthening chamber 30.

[0053] The drive unit 10 includes a motor 11, a time relay 12, a rotating shaft 13, and a thrust bearing 14. The rotating shaft 13 is used to fix the face gear 50 to be processed. The output shaft of the motor 11 is connected to the rotating shaft 13, driving the rotating shaft 13 to drive the face gear 50 to rotate synchronously. The thrust bearing 14 supports the rotating shaft 13, bears the weight of the entire suspension device, and transmits motion. The time relay 12 is connected to the motor 11 and is used to control the power-on / power-off time of the motor 11 to control the rotation of the face gear 50 at a specified angle, exposing the tooth root and tooth surface of the specified strengthening area to the strengthening range of the directional ultrasonic strengthening chamber 30.

[0054] An ultrasonic strengthening device 20 is positioned below the face gear 50 for performing ultrasonic impact gradient nano-strengthening treatment on the face gear 50. The ultrasonic strengthening device 20 includes an ultrasonic peening chamber, an ultrasonic probe 22, and a small ball. The ultrasonic peening chamber has openings at both its upper and lower ends. The ultrasonic probe 22 extends into the ultrasonic peening chamber from its lower opening. The small ball is placed on the ultrasonic probe 22, covering its upper surface. The upper opening of the ultrasonic peening chamber is positioned at the lower end of the face gear 50 to be processed, achieving a clearance fit. The ultrasonic probe 22 is connected to an ultrasonic generator.

[0055] The directional ultrasonic enhancement chamber 30 is positioned between the face gear 50 and the ultrasonic enhancement device 20, such as... Figure 3-4 As shown, the directional ultrasonic strengthening chamber 30 includes a first base 31, on which a through hole for accommodating the ultrasonic shot peening chamber is opened. A first gear tooth sealing raceway 32, a second gear tooth sealing raceway 33, and a tooth tip protection cover plate 34 are detachably installed sequentially on the upper end of the first base 31, with the first gear tooth sealing raceway 32 and the second gear tooth sealing raceway 33 respectively tightly disposed on both sides of the tooth tip protection cover plate 34. If the number of gear teeth processed simultaneously by the ultrasonic strengthening device 20 is M, then the tooth tip protection cover plate 34 has M impact through holes 341 whose dimensions are adapted to the tooth surface of the face gear 50. When M ≥ 1, the impact through holes 341 constitute the strengthening range of the directional ultrasonic strengthening chamber 30, exposing the tooth root and tooth surface to the small ball impact area, thus strengthening the designated area during strengthening. When M > 1, the cover plate between adjacent impact through holes 341 is a tooth tip protection part 342 whose dimensions are adapted to the tooth tip of the face gear 50, used to prevent the tooth tip from being exposed within the strengthening range.

[0056] The ultrasonic enhancement device 20 of the present invention works alternately with the time relay 12. When the ultrasonic enhancement device 20 is working, the motor 11 is de-energized, and when the motor 11 is energized, the ultrasonic enhancement device 20 stops working.

[0057] Let the output speed of motor 11 be n, where n ranges from 0 to 1000 rpm. What is the time required for the motor to rotate a unit angle?

[0058]

[0059] Therefore, the time required for one gear tooth to turn can be calculated:

[0060]

[0061] In the formula, N is the total number of teeth on the face gear (50).

[0062] The energizing time of time relay 12 is set to T1 = Mt; the de-energizing time of time relay 12 is the ultrasonic shock treatment time T2, where T2 = 1s ~ 1200s.

[0063] During use, after setting the pulse time of the ultrasonic generator, its working sequence is to first start the enhanced impact for T2 seconds, then stop for T1 seconds, and repeat the cycle. After setting the parameters of the time relay 12, its working sequence is to first power on for T1 seconds to start the motor 11, then power off for T2 seconds to stop the motor 11, and repeat the cycle. After setting the program, the ultrasonic generator needs to be turned on immediately after the motor 11 stops running.

[0064] In one embodiment of the present invention, such as Figure 3-4 As shown, the ultrasonic probe 22 has a diameter of 26mm and can process two tooth roots and surfaces simultaneously, i.e., M=2. Two impact holes 341 are provided on the tooth tip protective cover plate 34. One tooth tip protection part 342 between the two impact holes 341 blocks one tooth tip. The energizing time of the time relay 12 is set to T1=2t. During strengthening, the face gear 50 rotates two teeth each time by controlling the time relay 12 with an accuracy of 0.01s. When the time relay 12 is activated, the ultrasonic strengthening action stops. After rotating two tooth roots and surfaces, the strengthening action begins, and the designated area is exposed within the strengthening range. After strengthening is completed, the time relay 12 is energized to rotate the face gear 50 to the next designated area, and this process is repeated until strengthening is complete.

[0065] In other embodiments, ultrasonic nozzles of other sizes can also be used to process different numbers of teeth simultaneously, such as... Figure 5 The structure and parameter design of M=3 shown are similar to those of M=2, and will not be described in detail here.

[0066] During the processing, the first tooth sealing raceway 32 and the second tooth sealing raceway 33 not only restrict the sliding of the tooth top protective cover plate 34, but also play a more important role in sealing, preventing the small ball from escaping during reinforcement and avoiding danger. Furthermore, the split and detachable design allows for modular replacement after failure, reducing operation and processing costs; different tooth top protective covers plate 34 can also be replaced according to different processing requirements, improving the applicability of the testing device.

[0067] In a further optimization, the device of the present invention also includes a continuous ultrasonic strengthening chamber 40, which is used to replace the directional ultrasonic strengthening chamber 30 in situations where protection of the tooth tip is not required. Figure 6-9 As shown, the continuous ultrasonic strengthening chamber 40 includes a second base 41. The second base 41 has a through hole for accommodating the ultrasonic shot peening chamber. Symmetrically mounted on both sides of the through hole are ejector pin sliding columns 42. From bottom to top, springs 43 and sealing ejector pins 44 are sequentially fitted onto the ejector pin sliding columns 42. The top of the sealing ejector pin 44 is designed as a toothed ejector pin that meshes with the teeth of the face gear 50. Under the action of the spring 43's rebound force, the face gear 50 maintains a tight fit with the continuous ultrasonic strengthening chamber 40 during rotation, preventing the small ball from splashing out during impact. For applications where tooth tip protection is not required and processing efficiency is prioritized, simply replacing the directional ultrasonic strengthening chamber 30 with the continuous ultrasonic strengthening chamber 40 suffices, eliminating the need for a time relay 12. The continuous ultrasonic strengthening chamber 40 exposes the entire gear tooth within the strengthening chamber, allowing the small ball to continuously strike the tooth. By reducing the power of the ultrasonic generator and increasing the speed of the motor 11, micro-cracks at the tooth tip are avoided. After strengthening, the face gear surface quality is better, and overall rust removal is achieved, reducing processing steps.

[0068] Further optimization involves providing sliding grooves 311 on both sides of the upper end of the first base 31, and providing sliding parts that are adapted to the sliding grooves 311 on both sides of the first gear tooth sealing raceway 32, the second gear tooth sealing raceway 33, and the tooth top protective cover plate 34. The sliding parts are interference-fitted with the sliding grooves 311 and slide to the designated reinforcement area.

[0069] Further optimization involves connecting a motor 11 to the upper part of the rotating shaft 13, and threading a fixed gear screw 131 onto the lower part of the rotating shaft 13. The face gear 50 is mounted on the fixed gear screw 131, and screw nuts 15 are provided at both the upper and lower ends of the face gear 50 to adjust the gap between the face gear 50 and the upper opening of the ultrasonic shot peening chamber.

[0070] Further optimization includes two clamping cover plates 16. These two clamping cover plates 16 are respectively mounted on the rotating shaft 13 via lead screw nuts 15 at the upper and lower ends of the face gear 50, and are located on both sides of the face gear 50. This serves to both fix the face gear 50 and prevent uneven force distribution that could cause the device to loosen when the face gear 50 is impacted by small balls. The face gear 50 to be processed is installed between the two clamping cover plates 16, with a clearance fit between the clamping cover plates 16 and the face gear 50. The clamping cover plates 16 are fastened to the face gear 50 with bolts to achieve fixation and motion transmission of the face gear 50.

[0071] Further optimization includes a test bench 60, which comprises an upper support 61 and a lower support 62. A motor 11 is mounted above the upper support 61. The gear 50 to be processed and the directional ultrasonic strengthening chamber 30 are mounted between the upper support 61 and the lower support 62. The ultrasonic strengthening device 20 is mounted below the lower support 62. The ultrasonic strengthening device 20 can be mounted on a lifting frame to adjust the distance between the upper surface of the ultrasonic probe 22 and the raceway of the gear 50.

[0072] Further optimization: the time relay 12 adopts the YYC-2S relay, and its display has four significant digits, with the specific time accurate to three decimal places.

[0073] Further optimization has been achieved by using high-frequency ultrasound in the ultrasonic enhancement device 20, with a frequency of 20KHz to 10000KHz.

[0074] Further optimization resulted in the spheres having a diameter of 0.1mm to 10mm and the number of steel ball media ranging from 10 to 1000.

[0075] Accordingly, the present invention also proposes an ultrasonic impact gradient nano-strengthening method for face gear 50, which uses the above-mentioned ultrasonic impact gradient nano-strengthening device for face gear 50 to perform localized directional ultrasonic impact gradient nano-strengthening of face gear 50, including the following steps:

[0076] S1. Install the drive unit 10 and the directional ultrasonic enhancement chamber 30 above the ultrasonic probe 22, and make sure that the impact through hole 341 of the tooth top protective cover plate 34 should be aligned with the ultrasonic shot peening chamber.

[0077] S2. Set the energizing time of the time relay 12 so that the face gear rotates M teeth each time. The time relay starts to run. At this time, be careful not to turn on the ultrasonic strengthening device 20.

[0078] S3. After the time relay 12 completes one cycle, that is, after rotating M tooth roots and tooth surfaces, the ultrasonic strengthening device 20 is immediately turned on. At this time, the time relay 12 is de-energized, the face gear is stationary, the designated area (M tooth roots and tooth surfaces) is exposed within the strengthening range, and the strengthening begins.

[0079] S4. After the enhancement is completed, the ultrasonic enhancement device 20 stops, the time relay 12 is energized, and it rotates M teeth and stops; this process is repeated, and the directional region enhancement is completed through the time coupling of the time relay 12 and the ultrasonic enhancement device 20 until the enhancement is completed.

[0080] It should be noted that for construction projects that do not require protection of the tooth tip and prioritize processing efficiency, it is sufficient to replace the directional ultrasonic strengthening chamber 30 with the continuous ultrasonic strengthening chamber 40, and there is no need to install the time relay 12. Then, continuous ultrasonic strengthening treatment is performed on the tooth tip, tooth root, and tooth surface.

[0081] Furthermore, in gear failure modes, the tooth tip mainly fails due to microcracks, while the tooth surface and root experience root bending fatigue due to spalling and pitting. The tooth tip, tooth surface, and tooth root require different strengthening frequencies due to their different morphological locations. If single-direction strengthening is inefficient, a targeted approach—continuous strengthening followed by directional strengthening—can be adopted to address gear strengthening challenges. This allows for high-efficiency and precise strengthening to meet the requirements. Specifically, in continuous strengthening, a uniform low frequency is used only to meet the tooth tip strengthening requirements, while the tooth surface and root require directional strengthening by increasing the strengthening frequency to meet the overall gear strengthening needs.

[0082] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0083] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A surface gear ultrasonic impact gradient nano-reinforcement device, characterized in that, It includes a drive unit for driving the rotation of the face gear, an ultrasonic enhancement device, and a directional ultrasonic enhancement chamber; The driving device includes a motor, a time relay, and a rotating shaft. The rotating shaft is used to fix the face gear to be processed. The output shaft of the motor is connected to the rotating shaft, driving the rotating shaft to drive the face gear to rotate synchronously. The time relay is connected to the motor and is used to control the power-on / power-off time of the motor to control the rotation of the face gear at a specified angle, exposing the tooth root and tooth surface of the specified strengthening area within the strengthening range of the directional ultrasonic strengthening chamber. The ultrasonic strengthening device is located below the face gear and is used to perform ultrasonic impact gradient nano-strengthening treatment on the face gear. The ultrasonic strengthening device and the time relay work alternately. When the ultrasonic strengthening device is working, the motor is de-energized; when the motor is energized, the ultrasonic strengthening device stops working. The directional ultrasonic strengthening chamber is disposed between the face gear and the ultrasonic strengthening device. The directional ultrasonic strengthening chamber includes a first base, on which a through hole for accommodating the ultrasonic shot peening chamber is opened. The upper end of the first base is detachably installed with a first gear tooth sealing raceway, a second gear tooth sealing raceway, and a tooth tip protection cover plate. The first gear tooth sealing raceway and the second gear tooth sealing raceway are respectively tightly disposed on both sides of the tooth tip protection cover plate. The tooth tip protection cover plate is provided with M impact through holes of the size adapted to the tooth surface of the face gear, M≥1. The impact through holes are the strengthening range of the directional ultrasonic strengthening chamber. When M>1, the cover plate between adjacent impact through holes is a tooth tip protection part of the size adapted to the tooth tip of the face gear. Let the motor output speed be n, where n ranges from 0 to 1000 rpm. What is the time required for the motor to rotate one unit angle? (1) Therefore, the time required for one gear tooth to turn can be calculated: (2) In the formula, N is the total number of teeth on the face gear; The number of gear teeth processed simultaneously by the ultrasonic strengthening device is M, then the energizing time of the time relay is set to T1=Mt; the de-energizing time of the time relay is the ultrasonic shock treatment time T2, and the range of T2 is 1s~1200s.

2. The ultrasonic impact gradient nano-reinforcement device for face gears according to claim 1, characterized in that, The ultrasonic strengthening device includes an ultrasonic shot peening chamber, an ultrasonic probe, and a small ball. The ultrasonic shot peening chamber has openings at both the top and bottom. The ultrasonic probe extends into the ultrasonic shot peening chamber from the bottom opening. The small ball is placed on the ultrasonic probe and covers the upper surface of the ultrasonic probe. The top opening of the ultrasonic shot peening chamber is placed at the lower end of the gear on the surface to be machined, achieving a clearance fit.

3. The ultrasonic impact gradient nano-reinforcement device for face gears according to claim 1, characterized in that, The device also includes a continuous ultrasonic strengthening chamber, which is used to replace the directional ultrasonic strengthening chamber when no protection is required for the tooth tip.

4. The ultrasonic impact gradient nano-reinforcement device for face gears according to claim 3, characterized in that, The continuous ultrasonic enhancement chamber includes a second base with a through hole for accommodating the ultrasonic shot peening chamber. Symmetrical sliding pins are mounted on both sides of the through hole. A spring and a sealing pin are sequentially fitted onto each sliding pin from bottom to top. The top of the sealing pin is designed as a toothed pin that meshes with the teeth of a face gear. Under the action of the spring's rebound force, the face gear maintains a tight fit with the continuous ultrasonic enhancement chamber during rotation, preventing small balls from being ejected during impact.

5. The ultrasonic impact gradient nano-reinforcement device for face gears according to claim 1, characterized in that, The upper end of the first base is provided with sliding grooves on both sides. The first gear tooth sealing raceway, the second gear tooth sealing raceway, and the tooth top protective cover plate are respectively provided with sliding parts that are adapted to the sliding grooves. The sliding parts are interference-fitted with the sliding grooves and slide to the designated reinforcement area.

6. The ultrasonic impact gradient nano-reinforcement device for face gears according to claim 1, characterized in that, The upper part of the rotating shaft is connected to a motor, and the lower part of the rotating shaft is threaded to form a fixed gear screw. The face gear is installed on the fixed gear screw, and the upper and lower ends of the face gear are respectively provided with screw nuts for adjusting and fixing the position of the face gear.

7. The ultrasonic impact gradient nano-reinforcement device for face gears according to claim 6, characterized in that, The drive device also includes two clamping cover plates, which are fastened to both sides of the face gear by lead screw nuts at the upper and lower ends of the face gear.

8. The ultrasonic impact gradient nano-reinforcement device for face gears according to claim 1, characterized in that, The strengthening device also includes a test bench, which includes an upper support and a lower support. The motor is installed above the upper support, the gear to be processed and the directional ultrasonic strengthening chamber are installed between the upper support and the lower support, and the ultrasonic strengthening device is installed below the lower support.

9. A method for ultrasonic impact gradient nano-strengthening of face gears, characterized in that, The method of using the ultrasonic impact gradient nano-strengthening device for face gears as described in claim 1 to perform localized directional ultrasonic impact gradient nano-strengthening of face gears includes the following steps: S1. Install the drive unit and the directional ultrasonic enhancement chamber above the ultrasonic probe, and make sure that the impact through hole of the tooth top protective cover plate is aligned with the ultrasonic shot peening chamber. S2. Set the energizing time of the time relay so that the face gear rotates M teeth each time, and the time relay starts to run. At this time, be careful not to turn on the ultrasonic strengthening device. S3. After the time relay completes one cycle, i.e., after rotating M tooth roots and surfaces, immediately turn on the ultrasonic strengthening device. At this time, the time relay is de-energized, the face gear is stationary, the designated area is exposed within the strengthening range, and the strengthening begins. S4. After the enhancement is completed, the ultrasonic enhancement device stops, the time relay is energized, and it rotates M teeth to stop; this process is repeated to complete the directional area enhancement through time coupling between the time relay and the ultrasonic enhancement device until the enhancement is complete.

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