A one-way coupled vibration absorber for a generator with one-way enhanced friction damping
By designing a friction damping adjustment structure in the generator's one-way coupled vibration absorber, the resonance problem of the traditional OAD during the engine acceleration phase is solved, automatic adjustment of the friction force during the engine acceleration and deceleration phases is achieved, and the stability and NVH performance of the FEAD are improved.
Patent Information
- Application Number
- CN202311434384.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-31
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2043-10-31
AI Technical Summary
The traditional generator one-way coupled vibration absorber is prone to resonance during the engine acceleration phase, causing the OAD to repeatedly switch between the torsional vibration isolation function and the one-way overrunning function, affecting the stability of the FEAD.
A one-way coupled vibration absorber for a generator with one-way increased friction damping is designed. By setting a friction plate between the hub and the pulley and utilizing the structure and relative position of the friction plate, the friction damping is automatically increased during the engine acceleration phase and the friction force is automatically reduced during the deceleration phase, thereby achieving friction force regulation.
It effectively reduces the speed amplitude during the engine acceleration phase, improves the stability and NVH performance of FEAD, and avoids the problem of unstable torque transmission caused by resonance and improper friction.
Smart Images
Figure CN117267311B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of vibration dampers, in particular to a generator one-way coupling vibration damper with one-way improved friction damping. Background Art
[0002] The front-end accessory drive (FEAD) system is designed to transmit a portion of the engine crankshaft's output power via a belt to various engine accessories, such as the fan, water pump, generator, and air conditioning compressor, ensuring proper vehicle operation. The generator's output shaft is coaxially connected to the generator pulley.
[0003] Generator speed typically runs two to three times faster than the engine, resulting in a large moment of inertia. Generators operate continuously with the engine for extended periods, making them extremely sensitive to engine speed fluctuations. Under rapid acceleration and deceleration, these speed fluctuations cause significant fluctuations in the generator rotor, impacting the entire gear train. In most cases, this is the root cause of belt vibration, noise, slippage, and large swings in the tensioner arm. To mitigate the impact of sudden engine speed changes on the entire gear train, the use of overrunning alternator decouplers (OADs) has been gaining increasing attention. Their principle is to isolate the generator's moment of inertia from the entire gear train, improving the stability of the belt drive system.
[0004] OAD adds a one-way clutch and torsion spring between the originally rigidly connected generator pulley and motor rotor, creating an elastic connection between the two. When the engine is accelerating or operating at a steady constant speed, the outer pulley speed is greater than the motor rotor speed, the OAD clutch is engaged, and torque is transmitted to the motor rotor through the motor shaft and torsion spring, driving the motor rotor. The function of the torsion spring is to transform the rigid connection between the pulley and the rotor into a flexible connection, thereby reducing the torsional vibration transmitted from the engine to the generator (vibration isolation and vibration reduction between the pulley and the rotor); when the engine is decelerating, the outer pulley speed is less than the motor rotor speed, and the OAD's one-way clutch comes into play, separating the outer pulley from the motor rotor. The high-speed impact of the motor rotor cannot be transmitted to the outer pulley, improving the NVH performance of the system.
[0005] The OAD's primary structure consists of a ball bearing, pulley, clutch assembly, isolation spring, and hub. The ball bearing carries the entire radial load on the generator pulley; the pulley transmits the drive shaft's torque to the generator. The clutch assembly, a core component of the OAD, facilitates power transmission and decouples the pulley from the generator shaft during overrun. The isolation spring transfers power from the clutch assembly to the generator shaft. During forward rotation, the isolation spring's diameter increases, increasing friction between the clutch assembly's outer wall and the pulley's inner wall. Both the clutch assembly and hub have a retaining groove to limit the position of the isolation spring. The hub secures the OAD to the generator shaft. The clutch assembly includes a clutch spring that transfers torque from the pulley to the isolation spring during engine acceleration, thereby driving the hub. During engine deceleration, the pulley, isolation spring, and hub separate, allowing the hub to rotate freely.
[0006] From the structure of the OAD, we can see that the vibration isolation spring is connected in series between the clutch assembly and the hub, and has two main functions:
[0007] (1) Isolating torsional vibration: The engine torque is transmitted to the generator rotor through the drive belt, pulley, clutch assembly, vibration isolation spring, and hub, driving the generator to operate normally. When the engine accelerates, the clutch spring in the clutch assembly expands due to the pulley, and then connects to the inner wall of the pulley and the vibration isolation spring. At the same time, the vibration isolation spring pushes the hub to drive the generator. Because of the presence of the vibration isolation spring, the generator rotor speed will not accelerate synchronously with the engine, thus achieving the function of isolating torsional vibration.
[0008] (2) One-way overrunning function: When the active part drives the driven part, the two rotate together. If the speed of the driven part exceeds that of the active part, the two separate and the driven part can rotate freely. When the engine slows down, such as during the gear shifting process, the generator's rotor inertia is large, causing the tight side of the generator drive belt to become loose. In severe cases, it will cause the belt and pulley to slip, thereby generating noise and increasing belt wear. After the gear train uses OAD, when the engine slows down, the generator rotor drives the thrust plate through the hub, and the thrust plate pushes the clutch assembly. The diameter of the clutch spring in the clutch assembly is reduced, causing the hub, vibration isolation spring and the inner wall of the pulley to separate. The pulley slows down along with the drive belt, while the generator rotor still maintains a high speed rotation, thus achieving the one-way overrunning function.
[0009] Traditional OADs have the following problems: In certain application scenarios, the natural frequency of the OAD is close to the excitation frequency from the generator. During the engine acceleration phase, the two are prone to resonance, causing the OAD to repeatedly switch between the torsional vibration isolation function and the one-way overrunning function. In a short period of time, the speed of the pulley relative to the hub constantly changes suddenly, resulting in a large speed amplitude, affecting the normal transmission of torque between the two and reducing the stability of the FEAD. Summary of the Invention
[0010] The technical problem to be solved by the present invention is: in order to overcome the shortcomings of the existing technology, the present invention provides a generator one-way coupled vibration absorber with unidirectionally increased friction damping. During the engine acceleration stage, the structure and relative position of the shaft hub and friction plate are utilized to automatically increase the friction damping in one direction; during the engine deceleration stage, the structure and relative position of the shaft hub and friction plate are utilized to automatically reduce the friction damping.
[0011] The technical solution to be adopted by the present invention to solve its technical problem is: a one-way coupled vibration absorber for a generator with unidirectionally improved friction damping, comprising a pulley, a shaft hub and a friction plate, wherein the shaft hub is arranged in the center hole of the pulley, and a friction plate mounting groove is machined on the inner wall of the center hole of the pulley, and an annular boss is machined on one end of the shaft hub, and a plurality of arc-shaped bosses are arranged on the outer wall of the annular boss, and the outer wall contour of each of the arc-shaped bosses is an involute shape with the outer circumference of the annular boss as the base circle, and the number of the friction plates is equal to the number of the arc-shaped bosses. The number is the same, and a support area is provided on the rear part of the outer wall surface of the friction plate, which is embedded in the friction plate mounting groove to form a support surface. A gap is formed between the front part of the outer wall surface and the inner wall of the pulley center hole, and the end is against the front end surface of the adjacent arc-shaped boss at the rear. The front end of the friction plate extends toward the front arc-shaped boss, and a rear part of the inner side surface of the friction plate is in contact with the outer wall surface of the hub, and a front part is in contact with the outer wall surface of the arc-shaped boss, and the shape of the inner side surface of this part is complementary to the shape of the outer wall surface of the arc-shaped boss.
[0012] Furthermore, the roughness of the outer wall surface of the friction plate is greater than the roughness of the inner wall surface.
[0013] Furthermore, there are four arc-shaped bosses and four friction plates, which are evenly distributed along the circumferential direction.
[0014] Furthermore, a rounded transition is provided at the junction between the front and rear parts of the inner side surface of the friction plate.
[0015] Furthermore, the front end of the arc-shaped boss is provided with a rounded transition.
[0016] Furthermore, the curvature of the outer wall of the support area is the same as the curvature of the friction plate mounting groove.
[0017] Furthermore, the friction plate is made of elastic material.
[0018] Furthermore, it also includes a torsion spring, a bushing, a clutch spring, a thrust plate, a gasket and a bearing, wherein the torsion spring, bushing and clutch spring sleeve are arranged between the hub and the pulley from the inside to the outside, the upper end of the torsion spring is connected to the annular boss, and the lower end is connected to the thrust plate, the lower end of the hub and the pulley are connected through a bearing, and the gasket is arranged between the thrust plate and the bearing.
[0019] Furthermore, a torsion spring installation groove is processed on the side of the annular boss facing the hub for nesting the torsion spring, and a stop is processed in the torsion spring installation groove to abut against the end of the torsion spring.
[0020] Furthermore, the center of the hub is penetrated, and both ends of the inner wall are respectively processed with internal threads and internal hexagonal structures for connection with the output shaft of the generator.
[0021] The beneficial effects of the present invention are as follows: the present invention provides a one-way coupled vibration absorber for a generator with unidirectionally improved friction damping, redesigns the rotating friction element of the OAD (i.e., the friction ring nested between the shaft hub and the pulley in the traditional OAD), automatically increases the friction between the shaft hub and the pulley during the engine acceleration phase, and reduces the speed amplitude when the two resonate by increasing the friction damping in the vibration system; during the engine deceleration phase (one-way overtaking), automatically reduces the friction between the shaft hub and the pulley to ensure that the two are fully disengaged. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The present invention will be further described below with reference to the accompanying drawings and examples.
[0023] Figure 1 It is a side structural diagram of the one-way coupled vibration absorber of the generator of the present invention.
[0024] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure of AA.
[0025] Figure 3 yes Figure 2 Schematic diagram of the three-dimensional structure in mid-section.
[0026] Figure 4 yes Figure 1 Schematic diagram of the top view structure.
[0027] Figure 5 yes Figure 1 Schematic diagram of the cross-sectional structure of FF.
[0028] Figure 6 It is a schematic diagram of the three-dimensional structure of the hub and friction plate.
[0029] Figure 7 It is a schematic diagram of the side structure of the hub and friction plate.
[0030] Figure 8 yes Figure 7 Schematic diagram of the cross-sectional structure of CC.
[0031] Figure 9 yes Figure 7 Schematic diagram of the bottom-up structure of the axle hub.
[0032] Figure 10 It is a structural diagram of the friction plate.
[0033] Figure 11 It is a schematic diagram of the three-dimensional structure of the friction plate.
[0034] Figure 12 It is a schematic diagram of the cross-sectional structure of the pulley.
[0035] Figure 13 It is a schematic diagram of the working principle of the engine during the acceleration phase.
[0036] Figure 14 It is a schematic diagram of the working principle of the engine during the deceleration stage.
[0037] In the figure: 1. Pulley, 1.1. Friction plate mounting groove, 2. Hub, 2.1. Annular boss, 2.2. Arc-shaped boss, 2.3. Torsion spring mounting groove, 2.4. Stopper, 2.5. Fillet, 3. Torsion spring, 4. Friction plate, 4.1. End, 4.2. Support area, 4.3. Front end, 4.4. Inner side, 4.5. Outer wall, 4.6. Fillet, 5. Bushing, 6. Clutch spring, 7. Thrust plate, 8. Gasket, 9. Bearing, 10. Clearance, 11. Base circle, 12. Involute, 13. Support surface. DETAILED DESCRIPTION
[0038] The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, and therefore only shows the components related to the present invention.
[0039] like Figure 1-Figure 3 As shown, a one-way coupled generator vibration absorber with unidirectionally increased friction damping according to the present invention includes a pulley 1, a hub 2, a friction plate 4, a torsion spring 3, a bushing 5, a clutch spring 6, a thrust plate 7, a gasket 8, and a bearing 9. The torsion spring 3, bushing 5, and clutch spring 6 are arranged from the inside out between the hub 2 and the pulley 1. The upper end of the torsion spring 3 is connected to the annular boss 2.1, and the lower end is connected to the thrust plate 7. The hub 2 and the lower end of the pulley 1 are connected via a bearing 9. The gasket 8 is disposed between the thrust plate 7 and the bearing 9. The torsion spring 3, bushing 5, clutch spring 6, thrust plate 7, and gasket 8 are components of a conventional OAD and have the same structure and function. Among them, the torsion spring 3 transmits torque and reduces vibration between the pulley 1 and the hub 2; the friction plate 4 provides friction torque and damping when the hub 2 rotates; the clutch spring 6 connects the thrust plate 7 and the inner wall of the pulley 1 to transmit torque during the engine acceleration phase, and disconnects the thrust plate 7 and the inner wall of the pulley 1 to isolate the generator load and rotational inertia during the engine deceleration phase as described above; the gasket 8 is located between the bearing 9 and the thrust plate 7, and is used to connect the hub 2 and the thrust plate 7 and limit the bearing 9.
[0040] like Figure 2 As shown, the hub 2 is arranged in the center hole of the pulley 1, as shown in FIG. Figure 12 As shown, the inner wall of the center hole of the pulley 1 is processed with a friction plate 4 mounting groove 1.1, and the friction plate mounting groove 1.1 is a circular groove. Figure 5-Figure 9 As shown, the hub 2 is pierced through the center, with internal threads and internal hexagonal structures machined at both ends of the inner wall, respectively, for connection and removal with the generator output shaft (a conventional structure and installation method). An annular boss 2.1 is machined at one end of the hub 2. A torsion spring mounting groove 2.3 is machined on the side of the annular boss 2.1 facing the hub 2, for inserting the torsion spring 3. A stop 2.4 is machined within the torsion spring mounting groove 2.3 to abut the end of the torsion spring 3. Multiple arc-shaped bosses 2.2 are provided on the outer wall of the annular boss 2.1. The outer wall contour of each arc-shaped boss 2.2 is in the shape of an involute 12 with the outer circumference of the annular boss 2.1 as the base circle 11. The front end of each arc-shaped boss 2.2 is provided with a rounded corner 2.5 to avoid stress concentration and facilitate movement of the friction plate 4 on the hub 2. The number of the friction plates 4 is the same as the number of the arc-shaped bosses 2.2. The number of the arc-shaped bosses 2.2 is variable and can be designed according to the needs. In this embodiment, it is preferred that there are four arc-shaped bosses 2.2 and four friction plates 4, and they are evenly distributed along the circumferential direction. Figure 10 and Figure 11 As shown, the friction plate 4 is generally tooth-shaped, with the rearward portion of the tooth-shaped outer wall surface 4.5 being machined to form a support area 4.2 for supporting the hub 2 and pulley 1. This support area 4.2 is in the shape of a circular arc protrusion, and the outer wall curvature of the support area 4.2 is the same as the curvature of the friction plate 4 mounting groove 1.1 to ensure sufficient contact between the two, thereby transmitting the hub force between the pulley 1 and the hub 2. The support area 4.2 is embedded in the friction plate 4 mounting groove 1.1 to form a support surface 13. A gap 10 is formed between the forward portion of the outer wall surface 4.5 and the inner wall of the center hole of the pulley 1, and the distal end 4.1 abuts against the front end surface of the adjacent circular arc-shaped boss 2.2 at the rear.
[0041] A rearward portion of the inner side surface 4.4 of the friction plate 4 mates with the outer wall 4.5 of the hub 2. The front end 4.3 of the friction plate 4 extends forward toward a circular arc-shaped boss 2.2. The toothed inner wall, with the outer wall of the annular boss 2.1 of the hub 2 as its base circle 11, is machined with an involute 12 arc cut. The arc cut in the forward portion mates with the outer wall of the circular arc-shaped boss 2.2, and the shape of the inner side surface 4.4 of this portion complements the outer wall of the circular arc-shaped boss 2.2. The outer wall roughness of the friction plate 4 is greater than that of the inner wall. A fillet 4.6 transitions between the front and rear portions of the inner side surface 4.4 of the friction plate 4 (i.e., the area where the involute 12 intersects the base circle 11) to facilitate movement of the friction ring on the hub 2 and avoid stress concentration. The rounded corners at the ends of the cut facilitate movement of the friction ring on the hub 2 and avoid stress concentration. The friction plate 4 should be made of elastic material that is more susceptible to elastic deformation. Polishing or other methods should be used to make the roughness of the outer wall of the friction plate 4 greater than the roughness of the inner wall.
[0042] Installation relationship: Figure 5 As shown, before operation, the friction plate 4 is completely fitted with the hub 2, and the contours of their involute 12 and base circle 11 are also fitted; the support surface 13 of the friction ring is fitted with the inner circular groove of the pulley 1, constantly transmitting the hub force (caused by the belt pulling the pulley 1) between the pulley 1 and the hub 2, playing the role of supporting the hub 2; the flat end of the friction ring rests on the arc-shaped boss of the hub 2; the remaining part of the friction ring forms a gap 10 with the inner circular groove of the pulley 1.
[0043] Working principle:
[0044] like Figure 13 As shown, during the engine acceleration phase, the hub 2 rotates counterclockwise relative to the pulley 1. Due to the hub force, friction exists in the two support surfaces 13 shown. Since the roughness of the outer wall of the friction plate 4 is greater than that of the inner wall, the friction between the friction plate 4 and the pulley 1 is greater than the friction between the friction plate 4 and the hub 2, resulting in the relative position of the friction plate 4 and the pulley 1 remaining unchanged, while the hub 2 rotates counterclockwise relative to the friction plate 4. At the same time, the involute profile 12 on the hub 2 squeezes the involute profile 12 of the friction ring outward, and the end of the friction plate 4 moves outward (elastic deformation) with the support area 4.2 on the friction plate 4 as the fulcrum and contacts the pulley 1. Friction is generated between the hub, friction plate 4 and pulley 1. As the hub 2 rotates further, the force of the hub 2 squeezing the friction plate 4 increases, the normal pressure of the contact surface increases, and the friction between the hub, friction plate 4 and pulley 1 increases, thereby increasing the friction damping of the entire vibration system to reduce the speed amplitude during resonance.
[0045] like Figure 14As shown, during the engine deceleration stage, the hub 2 rotates clockwise relative to the pulley 1, and the friction plate 4 rotates synchronously with the hub 2. The hub 2 no longer squeezes the friction plate 4, and the friction plate 4 returns to its original state. The end of the friction plate 4 disengages from the pulley 1, reducing the friction force between the three and ensuring that the hub 2 and the pulley 1 are fully disengaged.
[0046] With the above-described preferred embodiments of the present invention as inspiration, and with reference to the above description, relevant personnel may make various changes and modifications without departing from the scope of the present invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. A one-way coupled vibration absorber for a generator with one-way enhanced friction damping, characterized in that: The cam is secured to the center of the hub and has a plurality of slots therein. The cam is secured to the center of the hub by a plurality of slots therein. The cams are secured to the center of the hub by a plurality of slots therein. The cams are secured to the center of the hub by a plurality of slots therein.
2. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 1, characterized in that: The roughness of the outer wall surface of the friction plate is greater than the roughness of the inner wall surface.
3. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 1, characterized in that: There are four arc-shaped bosses and four friction plates, which are evenly distributed along the circumferential direction.
4. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 1, characterized in that: A rounded transition is provided at the junction between the front and rear parts of the inner side surface of the friction plate.
5. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 1, characterized in that: The front end of the arc-shaped boss is provided with a rounded transition.
6. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 1, characterized in that: The curvature of the outer wall of the support area is the same as the curvature of the friction plate mounting groove.
7. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 1, characterized in that: The friction plate is made of elastic material.
8. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to any one of claims 1 to 7, characterized in that: It also includes a torsion spring, a bushing, a clutch spring, a thrust plate, a gasket and a bearing, wherein the torsion spring, bushing and clutch spring sleeve are arranged between the hub and the pulley from the inside to the outside, the upper end of the torsion spring is connected to the annular boss, and the lower end is connected to the thrust plate, the lower end of the hub and the pulley are connected through a bearing, and the gasket is arranged between the thrust plate and the bearing.
9. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 8, characterized in that: A torsion spring installation groove is processed on the side of the annular boss facing the hub for nesting the torsion spring, and a stop is processed in the torsion spring installation groove to abut against the end of the torsion spring.
10. The one-way coupled vibration absorber for a generator with one-way enhanced friction damping according to claim 8, characterized in that: The center of the hub passes through, and both ends of the inner wall are respectively processed with internal threads and internal hexagonal structures for connection with the output shaft of the generator.