Pulley decoupler

Abstract

The present invention relates to a pulley decoupler. The pulley decoupler comprises a coaxially arranged pulley, a core shaft, a decoupling spring, a sleeve, a torque spring, a thrust washer and a bearing, wherein the pulley is rotatably supported on the radial outer side of the core shaft through the bearing, the decoupling spring is torsionally connected to the pulley, the torque spring is torsionally connected to the core shaft, the sleeve is installed between the pulley and the core shaft in the radial direction and is torsionally connected between the decoupling spring and the torque spring in a unidirectional manner, the thrust washer abuts axially between the bearing and the sleeve, the pulley decoupler further comprises a limiting protrusion torsionally connected to the core shaft, the thrust washer is torsionally connected to the sleeve and has a limiting groove partially extending in the circumferential direction on the radial inner side, the limiting protrusion extends into the limiting groove toward the radial outer side and can rotate circumferentially in the limiting groove, thereby limiting the relative rotation range of the core shaft and the sleeve. The pulley decoupler of the present invention has a compact structure.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a pulley decoupler. Background Art

[0002] In the front end accessory drive (FEAD) of the engine, an alternator pulley decoupler (APD) is usually required. The pulley decoupler can compensate for the torsional vibrations introduced by the crankshaft of the internal combustion engine into its auxiliary belt drive. In the prior art, a one-way clutch is usually formed by the frictional engagement of a coil spring and a sleeve. This one-way clutch can transfer the driving torque from the pulley to the sleeve in the engaged state. The torque spring connected in series with the decoupling spring absorbs the torque vibrations from the belt drive by elastic deformation. When the pulley rotates with a delay, the one-way clutch opens, and no significant torque can be transferred from the sleeve to the pulley. Therefore, the generator shaft rotating by inertia can overtake the pulley.

[0003] For example, CN 109312789A discloses a pulley decoupler. The pulley decoupler has a first sleeve fixed on the radial inner side of the pulley, and a second sleeve is also installed on the inner side of the first sleeve. The decoupling spring is installed on the radial inner side of the two sleeves and is frictionally engaged with the two sleeves at the same time, and the torque spring is connected between the sleeve and the core shaft. In order to transmit torque between the two sleeves, the decoupling spring must have a sufficient axial length. In addition, in order to prevent the torque spring from slipping and causing its end to move away from the step surface when the core shaft exceeds the pulley, a groove for engaging the protrusions on the core shaft and the sleeve is also provided on the end of the torque spring, which has a significant effect on the structural strength and deformation capacity of the torque spring, and therefore it is necessary to increase the size of the spring to compensate. The above factors limit the compactness of the overall structure of the pulley decoupler. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a pulley decoupler with a compact structure.

[0005] The above technical problems are solved by a pulley decoupler according to the present invention. The pulley decoupler includes a coaxially arranged pulley, a core shaft, a decoupling spring, a sleeve, a torque spring, a thrust washer and a bearing, wherein the cylindrical pulley is rotatably supported on the radial outer side of the core shaft through the bearing, the decoupling spring is torsionally connected to the pulley, the torque spring is torsionally connected to the core shaft, the sleeve is installed between the pulley and the core shaft in the radial direction and is torsionally connected between the decoupling spring and the torque spring in a unidirectional manner, so that the decoupling spring and the sleeve constitute a one-way clutch; the thrust washer abuts axially between the bearing and the sleeve; wherein the pulley decoupler also includes a limiting protrusion torsionally connected to the core shaft, the thrust washer is torsionally connected to the sleeve and has a limiting groove partially extending in the circumferential direction on the radial inner side, the limiting protrusion extends radially outward into the limiting groove and can rotate circumferentially in the limiting groove.

[0006] The shape matching of the limiting groove and the limiting protrusion can limit the relative rotation range of the mandrel and the sleeve. When the pulley is torsionally connected to the torque spring through the one-way clutch composed of the decoupling spring and the sleeve and then torsionally connected to the mandrel, the torque spring can absorb the vibration of the torque through its own elastic deformation, the pulley and the mandrel rotate synchronously, and the limiting groove and the limiting protrusion do not work. When the rotation speed of the mandrel exceeds the pulley, the torque of the mandrel cannot be obviously transmitted to the pulley through the one-way clutch composed of the decoupling spring and the sleeve. At this time, since the connection between the torque spring and the mandrel and the sleeve is usually a one-way abutment along the circumferential direction, slippage may occur between the torque spring, the sleeve and the mandrel. The shape matching of the limiting groove and the limiting protrusion limits the relative rotation between the sleeve and the mandrel, preventing this slippage. And this constraint method does not require slotting on the torque spring, so a smaller torque spring can be used, thereby greatly improving the compactness of the structure and reducing the manufacturing cost.

[0007] According to a preferred embodiment of the present invention, the thrust washer may have an axial protrusion on the end face facing the sleeve, and accordingly, the sleeve may have an engagement feature portion, which is axially recessed on the end face of the sleeve facing the thrust washer, and the axial protrusion of the thrust washer is axially inserted into the engagement feature portion of the sleeve, thereby connecting the thrust washer to the sleeve in a torsion-resistant manner. In this case, the engagement feature portion may be a structure formed by stamping on the sleeve, so that the engagement feature portion protrudes axially on the end face of the sleeve facing away from the thrust washer, and the coil end of the torque spring can abut against the protruding end face of the engagement feature portion in the circumferential direction. In other words, the engagement feature portion can also be the original structure on the sleeve for torsionally connecting the torque spring, and the function of connecting with different components can be realized at the same time by using the protruding and recessed shapes of the stamping structure on its opposite sides.

[0008] According to another preferred embodiment of the present invention, when the sleeve transmits the torque of the decoupling spring to the torque spring, the limiting protrusion may not abut the limiting groove in the circumferential direction. This means that the rotation range of the limiting protrusion in the limiting groove is limited, so that when the one-way clutch transmits torque from the pulley to the core shaft, the torque can be transmitted through the torque spring, but not through the limiting groove and the limiting protrusion.

[0009] According to another preferred embodiment of the present invention, the pulley decoupler may include a limit ring mounted on the mandrel in a torsion-proof manner, the limit ring being located between the mandrel and the thrust washer in the radial direction, and the aforementioned limit protrusion being a radial protrusion formed on the radial outer side of the limit ring. Alternatively, the pulley decoupler may also include a limit key, and accordingly, the mandrel may have a keyway on the radial outer side, the limit key being fixed in the keyway, and the aforementioned limit protrusion being a radial protrusion formed on the radial outer side of the limit key.

[0010] According to another preferred embodiment of the present invention, the decoupling spring may have a hanging foot extending to the radially outer side of the decoupling spring at one end facing away from the sleeve, and accordingly, the pulley may have a flange fixed on the radially inner side and protruding radially inward, the flange having a hanging foot groove, the decoupling spring is mounted on the radially inner side of the pulley, and the hanging foot is inserted into the hanging foot groove. Therefore, the torsion-resistant connection between the pulley and the decoupling spring is achieved by the shape matching of the hanging foot groove and the hanging foot, which makes it unnecessary for the pulley and the decoupling spring to have a long-distance axial contact, thereby shortening the size of the decoupling spring.

[0011] According to another preferred embodiment of the present invention, the flange on the pulley can be formed integrally with the main body of the pulley. Alternatively, the flange can also be fixed to the main body of the pulley by interference fit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is further described below in conjunction with the accompanying drawings. The same reference numerals in the drawings represent elements with the same functions.

[0013] Figure 1 A cross-sectional view showing a pulley decoupler according to an embodiment of the present invention;

[0014] Figure 2 Show Figure 1 A perspective cutaway view of some components of a pulley decoupler;

[0015] Figure 3 A perspective view showing a sleeve of a pulley decoupler according to an embodiment of the present invention;

[0016] Figure 4 Show Figure 1 The disassembled and assembled states of some parts of the pulley decoupler; and

[0017] Figure 5 The exploded state and assembled state of some components of a pulley decoupler according to another embodiment of the present invention are shown. DETAILED DESCRIPTION

[0018] The following will describe the specific implementation of the pulley decoupler according to the present invention in conjunction with the accompanying drawings. The following detailed description and drawings are used to exemplarily illustrate the principles of the present invention. The present invention is not limited to the preferred embodiments described, and the protection scope of the present invention is defined by the claims.

[0019] According to an embodiment of the present invention, an alternator pulley decoupler installed in an engine front end accessory drive system is provided. Figure 1 1 shows a cross-sectional view of a pulley decoupler according to one embodiment of the present invention. Figure 1 As shown, the pulley decoupler comprises a coaxially arranged pulley 1, a core shaft 2, a decoupling spring 3, a sleeve 4 and a torque spring 5. The pulley 1 and the core shaft 2 are hollow cylindrical as a whole, and the pulley 1 is rotatably supported on the radial outer side of the core shaft 2 at both ends of the axial direction through a bearing 7 and a support washer 10. The core shaft 2 has an integrally formed main body section 21, a support section 22 and a connecting section 23. The main body section 21 and the support section 22 extend axially respectively. The support section 22 is coaxially arranged on the radial outer side of the main body section 21. The connecting section 23 extends radially approximately between the corresponding ends of the main body section 21 and the support section 22, thereby connecting the three sections into a whole. The main body section 21 and the support section 22 extend axially from the connecting section 23 to the same side, and the axial length of the main body section 21 is much greater than the axial extension length of the support section 22. One end of the pulley 1 is supported on the main body section 21 through the bearing 7 , and the other end is supported on the support section 22 through the support washer 10 .

[0020] The pulley 1 has an annular flange 11 protruding radially inward at the axial middle. The flange 11 can be an independent component fixed to the radial inner side of the main part of the pulley 1 by interference fit, or it can be a part formed integrally with the main part of the pulley 1. The flange 11 is located between the support section 22 and the bearing 7 in the axial direction. The sleeve 4 is coaxially installed between the pulley 1 and the main section 21 of the spindle 2 in the radial direction, and is located between the flange 11 and the bearing 7 in the axial direction. The sleeve 4 has a radial section 41 and an axial section 42. The radial section 41 is axially abutted on the bearing 7 through an annular thrust washer 6 on the side facing the bearing 1. The axial section 42 extends axially from the outer periphery of the radial section 41 away from the bearing 7. The decoupling spring 3 in the form of a coil spring is installed on the radial inner side of the axial section 42 and fits the inner surface of the axial section 42.

[0021] like Figure 2As shown, the coil end of the decoupling spring 3 away from the bearing 7 extends along the winding direction to the radial outside of the main part of the decoupling spring 3, thereby forming a hanging foot 31. A hanging foot groove 12 corresponding to the shape of the hanging foot 31 is formed on the flange 11, and the hanging foot 31 is inserted into the hanging foot groove 12 in a shape-matching manner. The hanging foot groove 12 can at least constrain the hanging foot 31 in the circumferential direction and the radial direction, so the rotation of the pulley 1 can be transmitted to the decoupling spring 3 through the cooperation between the hanging foot groove 12 and the hanging foot 31.

[0022] When the speed of the pulley 1 exceeds the sleeve 4 in the direction opposite to the winding direction of the decoupling spring 3, the pulley 1 will push the hanging foot 31 in the direction opposite to the winding direction, so that the decoupling spring 3 is elastically deformed and the radius is expanded. At this time, the decoupling spring 3 is tightly fitted to the inner surface of the axial section 42, and the large friction between the two causes the sleeve 4 to rotate synchronously with the decoupling spring 3, so the torque is transmitted to the sleeve 4 through the decoupling spring 3. When the speed of the pulley 1 is lower than that of the sleeve 4 in the direction opposite to the winding direction of the decoupling spring 3 (i.e., delay or overtaking occurs), the pulley 1 will drag the hanging foot 31 in the winding direction, so that the decoupling spring 3 is elastically deformed and the radius is contracted. At this time, the radial extrusion force of the decoupling spring 3 on the inner surface of the axial section 42 is reduced, and the friction between the two is not enough to maintain the synchronous rotation between the decoupling spring 3 and the sleeve 4, so the decoupling spring 3 and the sleeve 4 can rotate relative to each other, and no significant torque can be transmitted from the sleeve 4 to the decoupling spring 3. The decoupling spring 3 and the sleeve 4 thus constitute a one-way clutch that selectively transmits torque.

[0023] The torque spring 5 is also in the form of a coil spring. The torque spring 5 is coaxially arranged between the decoupling spring 3 and the main body section 21 of the core shaft 2. One end of the torque spring 5 axially abuts against the side of the axial section 41 facing away from the bearing 7, and the other end axially abuts against the side of the connecting section 23 facing the bearing 7. Figure 3As shown, the sleeve 4 is formed with an engagement feature 43 on the radial section 41. The engagement feature 43 is a structure formed by stamping on the thin-walled material of the sleeve 4. It is an axially concave portion on the side facing the bearing 7, and is correspondingly an axially convex portion on the side facing the torque spring 5. The engagement feature 43 has a flat circumferential end surface. When the decoupling spring 3 drives the sleeve 4 to rotate, the circumferential end surface of the engagement feature 43 will abut against the coil end of the torque spring 5 in the circumferential direction, thereby pushing the torque spring 5 to rotate in the same direction as the sleeve 4. For this reason, the torque spring 5 and the decoupling spring 3 have opposite coil winding directions. Correspondingly, a similar convex feature (not shown) is also formed on the connecting section 23 of the core shaft 2. When the sleeve 4 pushes the torque spring 5 to rotate, the coil end of the other end of the torque spring 5 will abut against the circumferential end surface of the convex feature in the circumferential direction, thereby pushing the core shaft 2 to rotate in the same direction as the torque spring 5. Therefore, when the rotation speed of the pulley 1 exceeds the sleeve 4 in the direction opposite to the winding direction of the decoupling spring 3, the torque of the pulley 1 can be transmitted to the mandrel 2 through the decoupling spring 3, the sleeve 4 and the torque spring 5 in sequence. The torque spring 5 can buffer the torque vibration transmitted to the mandrel 2 through its own elastic deformation.

[0024] The pulley decoupler further comprises a limiting ring 8 fixed by interference fit on the radial outer side of the main body section 21. The limiting ring 8 is installed in the same radial plane on the radial inner side of the thrust washer 6. The limiting ring 8 is coaxially arranged with the thrust washer 6 and can rotate relative to it. Figure 4 Schematic diagrams of the disassembled state and the assembled state of the sleeve 4, the thrust washer 6 and the limiting ring 8 are respectively shown. As shown in the figure, the thrust washer 6 is formed with a limiting groove 61 extending partially in the circumferential direction on the radial inner side, and an axial protrusion 62 is formed on the axial end face facing the sleeve 4. The axial protrusion 62 has a shape corresponding to the concave side of the engagement feature 43. The axial protrusion 62 is inserted into the corresponding engagement feature 43 in the axial direction, so as to connect the sleeve 4 and the thrust washer 6 in a torsion-proof manner. The limiting ring 8 is formed with a radial protrusion 81 extending toward the radial outer side on the radial outer side. The radial protrusion 81 is inserted into the limiting groove 61 in the radial direction, and the circumferential length of the radial protrusion 81 is less than the circumferential length of the limiting groove 61. Therefore, by the cooperation of the radial protrusion 81 and the limiting groove 61, the relative rotation range of the thrust washer 6 and the limiting ring 8 can be limited.

[0025] When the rotation speed of the pulley 1 exceeds the sleeve 4 in the direction opposite to the winding direction of the decoupling spring 3, the torque of the pulley 1 is transmitted to the mandrel 2 through the decoupling spring 3, the sleeve 4 and the torque spring 5, and the radial protrusion 81 and the limiting groove 61 are not engaged in the circumferential direction. When the rotation speed of the pulley 1 is lower than that of the sleeve 4 in the direction opposite to the winding direction of the decoupling spring 3, the torque of the pulley 1 cannot be significantly transmitted to the sleeve 4 and the mandrel 2 through the decoupling spring 3 and the sleeve 4, and the rotation speed of the mandrel 2 exceeds the pulley 1. At this time, the coil end of the torque spring 5 cannot abut the engagement feature 43 of the sleeve 4 in the circumferential direction, so the sleeve 4 may rotate in the opposite direction relative to the torque spring 5 and the mandrel 2. When the sleeve 4 rotates in the opposite direction relative to the mandrel 2 to a certain extent, the radial protrusion 81 and the limiting groove 61 will abut each other in the circumferential direction, so that the sleeve 4 begins to rotate synchronously with the mandrel 2 through the limiting ring 8. Therefore, when overrunning occurs, the reverse rotation of the sleeve 4 relative to the core shaft 2 is restricted, so that the coil end of the torque spring 5 will not be circumferentially away from the engagement end surface of the engagement feature 43. In this way, after the overrunning phenomenon is eliminated, when the torque of the pulley 1 is transmitted to the sleeve 4 again through the decoupling spring 3, the coil end of the torque spring 5 can quickly abut against the engagement feature 43, thereby avoiding the delay of torque transmission.

[0026] In the above embodiment, since the reverse rotation of the sleeve 4 relative to the mandrel 2 when overrunning occurs is restricted by the cooperation of the radial protrusion 81 on the limiting ring 8 and the limiting groove 61 on the thrust washer 6, it is not necessary to form a groove at the end of the torque spring 5 to cooperate with the protrusion on the sleeve 4 or the mandrel 2. This reduces the impact on the structural strength of the torque spring 5, so that the size of the torque spring can be reduced. In addition, since the pulley 1 and the decoupling spring 3 transmit torque through the hanging foot 31, there is no need to set a friction contact surface between the pulley 1 and the decoupling spring 3, which greatly shortens the axial length of the decoupling spring 3. Correspondingly, the axial length of the pulley 1 and the mandrel 2 can also be greatly shortened, thereby achieving the overall compactness of the pulley decoupler.

[0027] Figure 5 FIG. 2 shows a partial structure of a pulley decoupler according to another embodiment of the present invention. Figures 1 to 4 The difference between the pulley decoupler is that Figure 5The pulley decoupler is not provided with a limit ring 8, but with a limit key 9. The limit key 9 has a generally metal plate or sheet metal structure. The main body section 21 has an axially extending keyway 24 at one end where the bearing 7 is installed. The limit key 9 is inserted into the keyway 24 in a shape-fitting manner, thereby being fixed on the main body section 21 of the mandrel 2. The limit key 9 installed in the keyway 24 has a radial protrusion 91 extending radially outward at a position axially aligned with the thrust washer 6, and the radial protrusion 91 is radially inserted into the limit groove 61 on the thrust washer 6. The rest of the limit key 9 can be complementary to the shape of the keyway 24, so when the limit key 9 is installed in the keyway 24, the portion of the limit key 9 except the radial protrusion 91 together with the mandrel 2 constitutes a complete circumferential surface.

[0028] It should be noted that the technical solution of the present invention is to limit the reverse rotation of the sleeve 4 relative to the mandrel 2 by the cooperation of the limiting protrusion and the limiting groove 61 that are torsionally connected to the mandrel 2, so the limiting protrusion can also have other forms different from the above-mentioned embodiment. For example, the limiting protrusion can be a part formed integrally with the mandrel 2, or a part fixed to the mandrel 2 by other means or other parts.

[0029] Although possible embodiments are described by way of example in the above description, it should be understood that there are still a large number of variations of embodiments through the combination of all known and other technical features and embodiments that are easily conceivable to the skilled person. It should also be understood that the exemplary embodiment is only an example and that such an embodiment in no way limits the scope of protection, application and configuration of the present invention. The above description is more to provide the skilled person with a technical guide for converting at least one exemplary embodiment, wherein various changes can be made, especially changes in the functions and structures of the components, as long as they do not depart from the scope of protection of the claims.

[0030] Reference numerals list

[0031] 1 Pulley

[0032] 11 Flange

[0033] 12 Foot slots

[0034] 2 Mandrel

[0035] 21 Main body section

[0036] 22 Support section

[0037] 23 Connection section

[0038] 24 Keyway

[0039] 3 Decoupling spring

[0040] 31 Hanging feet

[0041] 4 Sleeve

[0042] 41 Radial section

[0043] 42 Axial section

[0044] 43 Engagement feature

[0045] 5 Torque spring

[0046] 6 Thrust washer

[0047] 61 Limiting slot

[0048] 62 Axial protrusion

[0049] 7 Bearings

[0050] 8 Limiting ring

[0051] 81 Radial protrusion

[0052] 9 Limit keys

[0053] 91 Radial protrusion

[0054] 10 Support washer

Claims

1. A pulley decoupler, comprising a coaxially arranged pulley (1), a core shaft (2), a decoupling spring (3), a sleeve (4), a torque spring (5), a thrust washer (6) and a bearing (7), wherein the pulley (1) is rotatably supported on the radial outer side of the core shaft (2) through the bearing (7), the decoupling spring (3) is torsionally connected to the pulley (1), the torque spring (5) is torsionally connected to the core shaft (2), the sleeve (4) is installed between the radial direction of the pulley (1) and the core shaft (2) and is unidirectionally torsionally connected between the decoupling spring (3) and the torque spring (5), and the thrust washer (6) is axially abutted between the bearing (7) and the sleeve (4), It is characterized in that The pulley decoupler also includes a limiting protrusion that is torsionally connected to the core shaft (2), the thrust washer (6) is torsionally connected to the sleeve (4) and has a limiting groove (61) that partially extends in the circumferential direction on the radial inner side, the limiting protrusion extends radially outward into the limiting groove (61) and can rotate circumferentially in the limiting groove (61), thereby limiting the relative rotation range of the core shaft (2) and the sleeve (4).

2. The pulley decoupler according to claim 1, characterized in that The thrust washer (6) has an axial protrusion (62) on the end face facing the sleeve (4), and the sleeve (4) has a coupling feature (43). The coupling feature (43) is axially recessed on the end face of the sleeve (4) facing the thrust washer (6), and the axial protrusion (62) is axially inserted into the coupling feature (43), thereby connecting the thrust washer (6) to the sleeve (4) in a torsion-proof manner.

3. The pulley decoupler according to claim 2, characterized in that The engaging feature portion (43) is a structure stamped on the sleeve (4), so that the engaging feature portion (43) protrudes axially on the end face of the sleeve (4) facing away from the thrust washer (6), and the coil end of the torsion spring (5) can abut against the protruding end face of the engaging feature portion (43) in the circumferential direction.

4. The pulley decoupler according to claim 1, characterized in that When the sleeve (4) transmits the torque of the decoupling spring (3) to the torque spring (5), the limiting protrusion does not abut against the limiting groove (61) in the circumferential direction.

5. The pulley decoupler according to claim 1, characterized in that: The pulley decoupler comprises a limiting ring (8) mounted on the core shaft (2) in a torsion-proof manner, the limiting ring (8) being located between the core shaft (2) and the thrust washer (6) in radial direction, and the limiting protrusion is a radial protrusion (81) formed on the radial outer side of the limiting ring (8).

6. The pulley decoupler according to claim 1, characterized in that The pulley decoupler comprises a limit key (9), the core shaft (2) has a keyway (24) on the radial outer side, the limit key (9) is fixed in the keyway (24), and the limit protrusion is a radial protrusion (91) formed on the radial outer side of the limit key (9).

7. The pulley decoupler according to any one of claims 1 to 6, characterized in that: The decoupling spring (3) has a hanging foot (31) extending to the radial outer side of the decoupling spring (3) at one end facing away from the sleeve (4); the pulley (1) has a flange (11) fixed on the radial inner side and protruding radially inward; the flange (11) has a hanging foot groove (12); the decoupling spring (3) is installed on the radial inner side of the pulley (1); the hanging foot (31) is inserted into the hanging foot groove (12), thereby connecting the pulley (1) and the decoupling spring (3) in a torsion-proof manner.

8. The pulley decoupler according to claim 7, characterized in that The flange (11) is formed integrally with the main body of the pulley (1).

9. The pulley decoupler according to claim 7, characterized in that: The flange (11) is fixed to the main body of the pulley (1) by interference fit.

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