阅读说明：本技术 皮带轮解耦器 (Belt pulley decoupler ) 是由 张忠学 王云 于 2020-04-03 设计创作，主要内容包括：本发明涉及一种皮带轮解耦器。该皮带轮解耦器包括同轴布置的皮带轮、芯轴、解耦弹簧、套筒、扭矩弹簧、止推垫圈和轴承,皮带轮通过轴承可转动地支撑在芯轴的径向外侧,解耦弹簧与皮带轮抗扭连接,扭矩弹簧与芯轴抗扭连接,套筒安装在皮带轮与芯轴的径向之间并且单向传扭地连接在解耦弹簧与扭矩弹簧之间,止推垫圈沿轴向抵接在轴承与套筒之间,该皮带轮解耦器还包括与芯轴抗扭连接的限位凸起,止推垫圈与套筒抗扭连接并且在径向内侧具有沿周向部分地延伸的限位槽,限位凸起向着径向外侧延伸到限位槽中,并且能够在限位槽中沿周向转动,从而限制芯轴与套筒的相对转动范围。本发明的皮带轮解耦器具有紧凑的结构。(The invention relates to a pulley decoupler. The pulley decoupler comprises a pulley, a mandrel, a decoupling spring, a sleeve, a torque spring, a thrust washer and a bearing which are coaxially arranged, wherein the pulley is rotatably supported on the radial outer side of the mandrel through the bearing, the decoupling spring is connected with the pulley in an anti-torsion manner, the torque spring is connected with the mandrel in an anti-torsion manner, the sleeve is arranged between the pulley and the mandrel in the radial direction and is connected between the decoupling spring and the torque spring in a one-way torque transmission manner, the thrust washer is abutted between the bearing and the sleeve in the axial direction, the pulley decoupler further comprises a limiting protrusion connected with the mandrel in an anti-torsion manner, the thrust washer is connected with the sleeve in an anti-torsion manner and is provided with a limiting groove partially extending in the circumferential direction on the radial inner side, and the limiting protrusion extends into the limiting groove towards the radial outer side and can rotate in the limiting groove in the circumferential direction, so that the relative rotation range of the mandrel and the sleeve is limited. The pulley decoupler of the present invention has a compact structure.)

1. A belt pulley decoupler comprising a coaxially arranged pulley (1), a spindle (2), a decoupling spring (3), a sleeve (4), a torque spring (5), a thrust washer (6) and a bearing (7), the pulley (1) being rotatably supported by the bearing (7) radially outside the spindle (2), the decoupling spring (3) being in rotationally fixed connection with the pulley (1), the torque spring (5) being in rotationally fixed connection with the spindle (2), the sleeve (4) being mounted radially between the pulley (1) and the spindle (2) and being unidirectionally torsionally connected between the decoupling spring (3) and the torque spring (5), the thrust washer (6) being axially abutted between the bearing (7) and the sleeve (4),

it is characterized in that the preparation method is characterized in that,

the pulley decoupler further comprises a stop lug which is connected to the spindle (2) in a rotationally fixed manner, the thrust washer (6) being connected to the sleeve (4) in a rotationally fixed manner and having a stop groove (61) which extends partially in the circumferential direction on the radial inside, the stop lug extending into the stop groove (61) towards the radial outside and being rotatable in the circumferential direction in the stop groove (61) in order to limit the relative rotational range of the spindle (2) and the sleeve (4).

2. The pulley decoupler according to claim 1, characterized in that the thrust washer (6) has an axial projection (62) on the end face facing the sleeve (4), the sleeve (4) has an engagement feature (43), the engagement feature (43) being recessed axially on the end face of the sleeve (4) facing the thrust washer (6), the axial projection (62) being inserted axially into the engagement feature (43) so as to connect the thrust washer (6) to the sleeve (4) in a rotationally fixed manner.

3. The pulley decoupler according to claim 2, characterized in that the engagement feature (43) is a structure stamped on the sleeve (4) such that the engagement feature (43) projects axially on the end face of the sleeve (4) facing away from the thrust washer (6), the coil end of the torque spring (5) being able to abut circumferentially on the projecting end face of the engagement feature (43).

4. The pulley decoupler as claimed in claim 1, characterized in that said stop lug does not circumferentially abut said stop groove (61) when said sleeve (4) transmits the torque of said decoupling spring (3) to said torque spring (5).

5. A pulley decoupler according to claim 1, characterised in that it comprises a stop collar (8) mounted non-rotatably on the spindle (2), the stop collar (8) being located radially between the spindle (2) and the thrust washer (6), the stop projection being a radial projection (81) formed on the radially outer side of the stop collar (8).

6. A pulley decoupler according to claim 1, characterised in that it comprises a limit key (9), the spindle (2) having a key groove (24) on the radial outside, the limit key (9) being fixed in the key groove (24), the limit projection being a radial projection (91) formed on the radial outside of the limit key (9).

7. A pulley decoupler according to any one of claims 1 to 6, characterised in that the decoupling spring (3) has, at the end facing away from the sleeve (4), a foot (31) which extends to the radially outer side of the decoupling spring (3), the pulley (1) has a flange (11) which is fixed to the radially inner side and projects radially inwards, the flange (11) has a foot slot (12), the decoupling spring (3) is mounted radially inside the pulley (1), the foot (31) being inserted into the foot slot (12) so as to connect the pulley (1) and the decoupling spring (3) in a rotationally fixed manner.

8. The pulley decoupler as claimed in claim 7, characterized in that said flange (11) is formed integrally with a body portion of the pulley (1).

9. The pulley decoupler as claimed in claim 7, characterized in that said flange (11) is fixed to the body portion of the pulley (1) by interference fit.

Technical Field

The invention relates to the technical field of engines. In particular, the present invention relates to a pulley decoupler.

Background

In an engine Front End Accessory Drive (FEAD), an Alternator Pulley Decoupler (APD) is typically required. The pulley decoupler is able to compensate for torsional vibrations introduced into its auxiliary belt drive by the crankshaft of the internal combustion engine. In the prior art, one-way clutches are typically constructed using frictional engagement of a coil spring with a sleeve. Such a one-way clutch is capable of transmitting a drive torque from the pulley to the sleeve in the engaged state. The torque spring connected in series with the decoupling spring absorbs torque vibrations from the belt drive through elastic deformation. When the pulley is delayed to rotate, the one-way clutch is opened, and no significant torque can be transmitted from the sleeve to the pulley, so that the inertia-rotating generator shaft can overrun the pulley.

For example, CN 109312789a discloses a pulley decoupler. The first sleeve is fixed on the radial inner side of the belt pulley decoupler, the second sleeve is further installed on the inner side of the first sleeve, the decoupling springs are installed on the radial inner sides of the two sleeves and are in friction joint with the two sleeves simultaneously, and the torque springs are connected between the sleeves and the mandrel. 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 away from the step surface when the spindle passes over the pulley, grooves are also provided on the ends of the torque spring for engaging projections on the spindle and sleeve, which has a significant effect on the structural strength and deformability of the torque spring, and therefore requires an increase in the size of the spring to compensate. All of the above factors limit the compactness of the overall structure of the pulley decoupler.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to provide a compact pulley decoupler.

The above-mentioned technical problem is solved by a pulley decoupler according to the invention. The belt pulley decoupler comprises a belt pulley, a mandrel, a decoupling spring, a sleeve, a torque spring, a thrust washer and a bearing which are coaxially arranged, wherein the cylindrical belt pulley is rotatably supported at the radial outer side of the mandrel through the bearing; the thrust washer is abutted between the bearing and the sleeve along the axial direction; the pulley decoupler further comprises a limiting protrusion connected with the mandrel in a rotationally fixed manner, the thrust washer is connected with the sleeve in a rotationally fixed manner and has a limiting groove extending partially in the circumferential direction on the radial inner side, and the limiting protrusion extends into the limiting groove towards the radial outer side and can rotate in the circumferential direction in the limiting groove.

The limiting groove is matched with the limiting bulge in shape, so that the relative rotation range of the mandrel and the sleeve can be limited. When the belt pulley is connected with the torque spring in an anti-torsion manner through the one-way clutch formed by the decoupling spring and the sleeve and further connected with the mandrel in an anti-torsion manner, the torque spring can absorb the vibration of torque through elastic deformation of the belt pulley and the mandrel, the belt pulley and the mandrel synchronously rotate, and the limiting groove and the limiting protrusion do not work. When the rotational speed of the spindle exceeds the pulley, the torque of the spindle cannot be significantly transmitted to the pulley through the one-way clutch formed by the decoupling spring and the sleeve. At this time, since the torque spring is usually connected to the spindle and the sleeve in a one-way contact manner in the circumferential direction, a slip phenomenon may occur between the torque spring, the sleeve, and the spindle. The relative rotation between the sleeve and the mandrel is limited by the shape matching of the limiting groove and the limiting bulge, and the slipping phenomenon is prevented. And the constraint mode does not need to slot on the torque spring, so that the torque spring with smaller size can be adopted, thereby greatly improving the structural compactness and reducing the manufacturing cost.

According to a preferred embodiment of the invention, the thrust washer may have an axial projection on an end face facing the sleeve, and correspondingly, the sleeve may have an engagement feature which is recessed axially on an end face of the sleeve facing the thrust washer, the axial projection of the thrust washer being inserted axially into the engagement feature of the sleeve, thereby connecting the thrust washer to the sleeve in a rotationally fixed manner. In this case, the engagement feature may be a structure stamped and formed on the sleeve such that the engagement feature projects axially on an end face of the sleeve facing away from the thrust washer, the coil end of the torsion spring being able to abut circumferentially onto the projecting end face of the engagement feature. In other words, the engagement feature may simultaneously be the original structure on the sleeve for the torque-proof connection of the torsion spring, with the male and female shapes respectively provided on opposite sides thereof by the stamped structure, while fulfilling the function of connection with different components.

According to another preferred embodiment of the invention, the stop projection may not abut the stop groove in the circumferential direction when the sleeve transmits the torque of the decoupling spring to the torque spring. This means a limitation of the rotation range of the limit projection in the limit groove, so that when the one-way clutch transmits torque from the pulley to the spindle, torque can be transmitted through the torque spring, and not through the limit groove and the limit projection.

According to a further preferred embodiment of the invention, the pulley decoupler may comprise a stop collar mounted non-rotatably on the spindle, the stop collar being located radially between the spindle and the thrust washer, the aforementioned stop lug being formed by a radial lug formed on the radially outer side of the stop collar. Alternatively, the pulley decoupler may also comprise a limit key, in which the spindle may have a key groove on the radial outside, in which the aforementioned limit projection is acted upon by a radial projection formed on the radial outside of the limit key.

According to a further preferred embodiment of the invention, the decoupling spring can have a foot at the end facing away from the sleeve which extends to the radially outer side of the decoupling spring, and correspondingly the pulley can have a flange which is fixed on the radially inner side and projects radially inward and which has a foot groove, the decoupling spring being mounted on the radially inner side of the pulley, the foot being inserted into the foot groove. The rotationally fixed connection between the belt pulley and the decoupling spring is thus realized by a form fit of the lug groove and the lug, which makes no long-distance axial contact between the belt pulley and the decoupling spring necessary, so that the size of the decoupling spring can be shortened.

According to another preferred embodiment of the invention, the flange on the pulley may be integrally formed with the body portion of the pulley. Alternatively, the flange may be secured to the body portion of the pulley by an interference fit.

Drawings

The invention is further described below with reference to the accompanying drawings. Identical reference numbers in the figures denote functionally identical elements. Wherein:

FIG. 1 shows a cross-sectional view of a pulley decoupler according to an embodiment of the invention;

FIG. 2 shows a perspective cross-sectional view of a portion of the components of the pulley decoupler of FIG. 1;

FIG. 3 shows a perspective view of a sleeve of a pulley decoupler according to an embodiment of the invention;

FIG. 4 shows exploded and assembled states of parts of the pulley decoupler of FIG. 1; and

FIG. 5 illustrates an exploded and assembled state of portions of a pulley decoupler according to another embodiment of the invention.

Detailed Description

Specific embodiments of a pulley decoupler according to the present invention will be described below with reference to the accompanying drawings. The following detailed description and drawings are included to illustrate the principles of the invention, which is not to be limited to the preferred embodiments described, but is to be defined by the appended claims.

In accordance with an embodiment of the present invention, an alternator pulley decoupler is provided for installation in an engine front end accessory drive system. FIG. 1 shows a cross-sectional view of a pulley decoupler according to one embodiment of the invention. As shown in fig. 1, the pulley decoupler comprises a coaxially arranged pulley 1, a spindle 2, a decoupling spring 3, a sleeve 4 and a torque spring 5. The pulley 1 and the mandrel 2 are hollow cylindrical as a whole, respectively, and the pulley 1 is rotatably supported at both axial ends on the radially outer side of the mandrel 2 by bearings 7 and support washers 10, respectively. The mandrel 2 has an integrally formed main section 21, a support section 22 and a connecting section 23, the main section 21 and the support section 22 extending axially respectively, the support section 22 being arranged coaxially radially outside the main section 21, the connecting section 23 extending substantially radially between the respective ends of the main section 21 and the support section 22, thereby connecting the three sections together as a unit. The main section 21 and the support section 22 extend axially from the connection section 23 towards the same side, the axial length of the main section 21 being much greater than the axial extension of the support section 22. The pulley 1 is supported at one end on the main section 21 by means of a bearing 7 and at the other end on the support section 22 by means of a support washer 10.

Pulley 1 has at an axial middle portion an annular flange 11 projecting radially inwards. Flange 11 may be a separate member fixed to the radially inner side of the main body portion of pulley 1 by interference fit, or may be a portion integrally formed with the main body portion of pulley 1. The flange 11 is located axially between the support section 22 and the bearing 7. The sleeve 4 is mounted radially coaxially between the pulley 1 and the body section 21 of the spindle 2 and axially between the flange 11 and the bearing 7. The sleeve 4 has a radial section 41 and an axial section 42. The side of the radial section 41 facing the bearing 1 is in axial abutment with the bearing 7 by means of an annular thrust washer 6. The axial section 42 extends axially from the outer circumference of the radial section 41, facing away from the bearing 7. A decoupling spring 3 in the form of a helical spring is mounted radially inside the axial section 42 and abuts the inner surface of the axial section 42.

As shown in fig. 2, the coil end of the decoupling spring 3 remote from the bearing 7 extends in the winding direction to the radially outer side of the main body portion of the decoupling spring 3, thereby forming a hanger 31. The flange 11 is formed with a leg groove 12 corresponding to the shape of the leg 31, and the leg 31 is inserted into the leg groove 12 in a shape-fitting manner. The hitching leg 31 can be restrained at least in the circumferential direction and in the radial direction by the hitching leg groove 12, so that the rotation of the pulley 1 can be transmitted to the decoupling spring 3 by the cooperation of the hitching leg groove 12 and the hitching leg 31.

When the rotational speed of the pulley 1 exceeds the sleeve 4 in the winding direction against the decoupling spring 3, the pulley 1 pushes the foot 31 against the winding direction, so that the decoupling spring 3 is elastically deformed to expand the radius. At this time, the decoupling spring 3 closely contacts the inner surface of the axial section 42, and the sleeve 4 rotates synchronously with the decoupling spring 3 due to the large friction force between the two, so that the torque is transmitted to the sleeve 4 through the decoupling spring 3. When the rotational speed of the pulley 1 is lower than the sleeve 4 in the winding direction against the decoupling spring 3 (i.e. a delay or overrun occurs), the pulley 1 will drag the suspension foot 31 in the winding direction, so that the decoupling spring 3 deforms elastically and contracts in radius. At this time, the radial pressing force of the decoupling spring 3 against the inner surface of the axial section 42 is reduced, and the friction force therebetween is insufficient to maintain the synchronous rotation between the decoupling spring 3 and the sleeve 4, so that relative rotation can occur between the decoupling spring 3 and the sleeve 4, 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 which selectively transmits torque.

The torsion spring 5 is likewise in the form of a helical spring. The torsion spring 5 is arranged coaxially between the decoupling spring 3 and the main body section 21 of the spindle 2. One end of the torsion spring 5 axially abuts on the side of the axial section 41 facing away from the bearing 7, and the other end axially abuts on the side of the connecting section 23 facing the bearing 7. As shown in fig. 3, the sleeve 4 is formed with engagement features 43 on the radial section 41. The engagement feature 43 is a structure stamped out of the thin-walled material of the sleeve 4, which exhibits an axially concave portion on the side facing the bearing 7 and correspondingly an axially convex portion on the side facing the torsion spring 5. The engagement features 43 have flat circumferential end faces, which circumferential end faces of the engagement features 43 will abut circumferentially on the coil ends of the torsion spring 5 when the decoupling spring 3 rotates the sleeve 4, thereby pushing the torsion spring 5 to rotate with the sleeve 4 in the same direction. For this purpose, the torsion spring 5 and the decoupling spring 3 have opposite coil winding directions. Correspondingly, a similar raised feature (not shown) is also formed on the connecting section 23 of the mandrel 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 mandrel 2 to rotate with the torque spring 5 in the same direction. Thus, when the rotational speed of the pulley 1 exceeds the sleeve 4 in the winding direction against the decoupling spring 3, the torque of the pulley 1 can be transmitted to the spindle 2 sequentially through the decoupling spring 3, the sleeve 4 and the torque spring 5. The torque spring 5 can damp the torque vibration transmitted to the spindle 2 by its elastic deformation.

The pulley decoupler further comprises a stop collar 8 fixed radially outwardly of the body section 21 by interference fit. The stop collar 8 is mounted radially inwardly of the thrust washer 6 in the same radial plane. The stop collar 8 is arranged coaxially with the thrust washer 6 and can rotate relative thereto. Fig. 4 shows a schematic view of the sleeve 4, the thrust washer 6 and the stop collar 8 in a disassembled state and in an assembled state, respectively. As shown in the drawing, the thrust washer 6 is formed with a stopper groove 61 extending partially in the circumferential direction on the radially inner side, and is formed with an axial protrusion 62 on the axial end surface facing the sleeve 4. The axial projection 62 has a shape corresponding to the concave side of the engagement feature 43. The axial projections 62 are inserted axially into the corresponding engagement features 43, so that the sleeve 4 is connected to the thrust washer 6 in a rotationally fixed manner. The retainer ring 8 has a radial projection 81 extending radially outward on the radially outer side. The radial projection 81 is radially inserted into the stopper groove 61, and the circumferential length of the radial projection 81 is smaller than that of the stopper groove 61. Therefore, the relative rotation range of the thrust washer 6 and the retainer ring 8 can be restricted by the engagement of the radial projections 81 and the retainer grooves 61.

When the rotational speed of the pulley 1 exceeds the sleeve 4 in the winding direction against the decoupling spring 3, the torque of the pulley 1 is transmitted to the spindle 2 through the decoupling spring 3, the sleeve 4 and the torque spring 5, and the radial protrusion 81 and the limit groove 61 are not engaged in the circumferential direction. When the rotational speed of the pulley 1 is lower than the sleeve 4 in the winding direction against the decoupling spring 3, the torque of the pulley 1 cannot be significantly transmitted to the sleeve 4 and the spindle 2 through the decoupling spring 3 and the sleeve 4, and the rotational speed of the spindle 2 exceeds the pulley 1. At this time, the coil end of the torque spring 5 cannot circumferentially abut the engagement feature 43 of the sleeve 4, and therefore the sleeve 4 may be rotated in the reverse direction with respect to the torque spring 5 and the spindle 2. When the sleeve 4 is rotated in the reverse direction with respect to the spindle 2 to some extent, the radial projection 81 and the stopper groove 61 abut against each other in the circumferential direction, so that the sleeve 4 starts to rotate synchronously with the spindle 2 via the stopper ring 8. Thus, when overrunning occurs, reverse rotation of the sleeve 4 relative to the mandrel 2 is restricted so that the coil ends of the torque spring 5 do not move away from the engagement end surfaces of the engagement features 43 in the circumferential direction. In this way, when the torque of the pulley 1 is transmitted again to the sleeve 4 through the decoupling spring 3 after the overrunning phenomenon is eliminated, the coil ends of the torque spring 5 can be promptly abutted onto the engagement features 43, thereby avoiding a delay in torque transmission.

In the above embodiment, since the reverse rotation of the sleeve 4 relative to the spindle 2 when overrun occurs is restrained by the engagement of the radial projections 81 on the stop collar 8 with the stop grooves 61 on the thrust washer 6, there is no need to form a recess in the end of the torsion spring 5 to engage with the projections on the sleeve 4 or the spindle 2. This reduces the influence on the structural strength of the torsion spring 5, so that the torsion spring can be downsized. In addition, because the pulley 1 and the decoupling spring 3 transmit torque through the hitching leg 31, a friction contact surface is not required to be arranged between the pulley 1 and the decoupling spring 3, so that the axial length of the decoupling spring 3 can be greatly shortened, and correspondingly, the axial lengths of the pulley 1 and the mandrel 2 can also be greatly shortened, thereby realizing the integral compactness of the pulley decoupler.

FIG. 5 shows a partial structure of a pulley decoupler according to another embodiment of the invention. The pulley decoupler of this embodiment differs from the pulley decoupler of fig. 1 to 4 in that the pulley decoupler of fig. 5 is not provided with a stop collar 8 but with a stop key 9. The stopper key 9 generally has a metal plate or sheet metal configuration. The body section 21 has an axially extending keyway 24 at one end at which the bearing 7 is mounted. The locking key 9 is inserted into the key groove 24 in a form-fitting manner and is thus fixed to the body section 21 of the spindle 2. The stopper key 9 fitted in the key groove 24 has a radial projection 91 extending radially outward at a position axially aligned with the thrust washer 6, and the radial projection 91 is radially inserted into the stopper groove 61 on the thrust washer 6. The remaining part of the limit key 9 may be complementary to the shape of the keyway 24, so that when the limit key 9 is mounted in the keyway 24, the part of the limit key 9 other than the radial projection 91 constitutes a complete circumferential surface with the spindle 2.

It should be noted that the solution according to the invention is intended to limit the counter-rotation of the sleeve 4 with respect to the mandrel 2 by means of the cooperation of the limiting projection and the limiting groove 61, which are non-rotatably connected to the mandrel 2, and therefore the limiting projection may also have other forms than the above-described embodiment. For example, the stop projection may be a portion integrally formed with the spindle 2, or a member fixed to the spindle 2 by another means or other member.

Although possible embodiments have been described by way of example in the above description, it should be understood that numerous embodiment variations exist, still by way of combination of all technical features and embodiments that are known and that are obvious to a person skilled in the art. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. From the foregoing description, one of ordinary skill in the art will more particularly provide a technical guide to convert at least one exemplary embodiment, wherein various changes may be made, particularly in matters of function and structure of the components described, without departing from the scope of the following claims.

List of reference numerals

1 Belt pulley

11 Flange

12 hitching leg groove

2 mandrel

21 body section

22 support section

23 connecting section

24 key groove

3 decoupling spring

31 hanging feet

4 sleeve

41 radial segment

42 axial section

43 engagement feature

5 torsion spring

6 thrust washer

61 limiting groove

62 axial projection

7 bearing

8 spacing ring

81 radial projection

9 limiting key

91 radial projection

10 support washer