CN111425581A

CN111425581A - Belt pulley decoupler

Info

Publication number: CN111425581A
Application number: CN201910019218.4A
Authority: CN
Inventors: 唐中伍; 刘轶琨; 李定
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Holding China Co Ltd
Priority date: 2019-01-09
Filing date: 2019-01-09
Publication date: 2020-07-17

Abstract

The invention relates to a pulley decoupler. Disclosed is a pulley decoupler comprising: a pulley (10) comprising a cavity extending in an axial direction; a bushing (20) coaxially and rotatably arranged in the cavity of the pulley (10), the bushing (20) comprising a protrusion (23); a first sleeve (50) disposed coaxially and torsionally in the cavity of the pulley (10), the first sleeve (50) comprising a first support (52), the first support (52) being axially spaced from the protrusion (23); and a seal member (100) disposed between the first support portion (52) and the projection (23), wherein the seal member (100) is configured in a ring shape and includes a joint portion (110) and a seal lip (120), the joint portion (110) is connected to one of the first support portion (52) and the projection (23), and the seal lip (120) is disposed against the other of the first support portion (52) and the projection (23).

Description

Belt pulley decoupler

Technical Field

The invention relates to a pulley decoupler. More particularly, the present invention relates to a pulley decoupler with an end seal.

Background

The generator in the accessory drive has a very high moment of inertia and therefore has a very large influence on the operation of the pulley system. The pulley decoupler can compensate for torsional vibrations and torsional non-uniformities introduced into the belt drive from the crankshaft of the internal combustion engine. The pulley decoupler is typically disposed on the generator as a generator pulley decoupler (APD). The pulley decoupler allows the drive shaft of the generator to overrun or rotate at a higher speed than the pulley.

The known pulley decoupler is sealed on the side remote from the generator only by the end cap, without a seal being provided. Lubricant often leaks from the working chamber of the pulley decoupler. In testing of pulley decouplers, frequent removal and installation of the end caps is required, and additional return of leaked lubricant to the working chamber is required. Since the end cap needs to be mounted on the pulley decoupler during testing, the temperature of the shaft end cannot be externally detected by the infrared sensor.

For this reason, a pulley decoupler with a seal on the side remote from the generator is required.

Disclosure of Invention

It is an object of the present invention to provide a pulley decoupler having a seal on the side away from the generator. It is another object of the present invention to provide a pulley decoupler that prevents lubricant from leaking after the end cap is removed. It is another object of the present invention to provide a pulley decoupler that enables the end cap to be removed during testing to externally sense the temperature of the shaft end.

One aspect of the invention provides a pulley decoupler comprising: a pulley comprising an axially extending cavity; a bushing coaxially and rotatably disposed in the cavity of the pulley, the bushing including a protrusion; a first sleeve disposed coaxially and torsionally in the cavity of the pulley, the first sleeve including a first support axially spaced from the protrusion; and a seal member disposed between the first support portion and the projection, wherein the seal member is configured in a ring shape and includes an engaging portion and a seal lip, the engaging portion is connected to one of the first support portion and the projection, and the seal lip is disposed against the other of the first support portion and the projection.

According to an embodiment of the invention, the engagement portion of the seal is connected to the projection of the shaft sleeve, and the sealing lip of the seal is arranged against the first support portion of the first sleeve.

According to an embodiment of the present invention, the engagement portion of the seal member is fitted over an end portion of the projection of the boss toward the first support portion by elastic deformation.

According to an embodiment of the present invention, the protrusion of the bushing has a first surface facing the first sleeve in an axial direction and a second surface facing the pulley in a radial direction, and the engagement portion of the seal has a stepped structure to form an interference fit with the first surface and the second surface of the protrusion, respectively.

According to an embodiment of the invention, the seal is made of a rubber material.

According to an embodiment of the present invention, the seal lip is provided to extend obliquely toward the radially inner side from the joint portion.

According to an embodiment of the invention, the pulley decoupler has a first side and a second side that are axially opposite, the bushing further comprises a first shaft portion that extends in the axial direction and a connecting portion that extends radially outward from an end of the first shaft portion on the first side to a protrusion that extends from the connecting portion in the axial direction to the second side, and the first sleeve further comprises a second shaft portion that extends in the axial direction and is disposed radially between the first shaft portion and the pulley, the first support portion extending radially inward from the second shaft portion.

According to an embodiment of the invention, the pulley decoupler further comprises: a torsion spring disposed axially around at least a portion of the first shaft portion of the bushing; a wrap spring disposed radially between the pulley and the torsion spring; a second sleeve including a third shaft portion extending in an axial direction and disposed between the wrap spring and the first sleeve in a radial direction, and a second support portion extending inward in the radial direction from the third shaft portion, axial end portions of the torsion spring being supported on the connecting portion and the second support portion of the second sleeve, respectively, and axial end portions of the wrap spring being supported on the first support portion of the first sleeve and the second support portion of the second sleeve, respectively; and an end cap connected to an end of the pulley on the first side.

According to an embodiment of the invention, the sleeve, the first sleeve, the second sleeve and the seal form a sealed annular housing, wherein the torsion spring and the surrounding spring are arranged in the annular housing.

According to the embodiment of the invention, the sealing element is arranged on the side, away from the generator, of the pulley decoupler, so that the lubricant can be effectively prevented or reduced from leaking from the working chamber, and the efficiency and the service life of the pulley decoupler are improved. Thus, frequent removal of the end caps to handle leaked lubricant is not required, further improving the efficiency of use of the pulley decoupler and reducing costs. Since the lubricant can be effectively prevented from leaking, the end cover can be detached from the pulley decoupler in the test process to detect the temperature of the shaft end externally using an infrared sensor or the like.

Drawings

FIG. 1 is a cross-sectional view of a pulley decoupler.

FIG. 2 is a perspective exploded view of a pulley decoupler.

FIG. 3 is a cross-sectional view of a pulley decoupler with a seal according to an embodiment of the invention.

FIG. 4 is an enlarged partial view of a pulley decoupler according to an embodiment of the invention.

Detailed Description

Hereinafter, embodiments of the present invention are described with reference to the drawings. The following detailed description and drawings are illustrative of the principles of the invention, which is not limited to the preferred embodiments described, but is defined by the claims. The invention will now be described in detail with reference to exemplary embodiments thereof, some of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, in which like reference numerals refer to the same or similar elements in different drawings unless otherwise indicated. The aspects described in the following exemplary embodiments do not represent all aspects of the present invention. Rather, these aspects are merely exemplary of the systems and methods according to the various aspects of the present invention as recited in the appended claims.

FIG. 1 is a cross-sectional view of a pulley decoupler. FIG. 2 is a perspective exploded view of a pulley decoupler. The pulley decoupler may include a pulley 10, a bushing 20, a torsion spring 30, a wrap spring 40, a first sleeve 50, a second sleeve 60, and an end cap 70. The pulley decoupler has an axis of rotation X and has axially opposed first and second sides a, B. In the exemplary embodiment, the first side a is the side remote from the generator (not shown) and the second side B is the side close to the generator.

Pulley 10 may have a hollow cylindrical configuration. Pulley 10 includes an axially extending cavity. Pulley 100 includes an outer surface 11 around which a belt (not shown) is wrapped, which may be shaped according to the multi-groove shape of the belt (multi-V groove shape). The belt may drive pulley 10 in rotation in a direction perpendicular to the plane of the paper in fig. 1.

Bushing 20 may be coaxially disposed within the cavity of pulley 10. Pulley 10 is rotatably supported on bushing 20. The sleeve 20 may include a shaft portion 21, a connecting portion 22, and a protruding portion 23. The shaft portion 21 and the protruding portion 23 extend in the axial direction. The connecting portion 22 extends radially outward from the end of the shaft portion 21 on the first side a to the protruding portion 23. The projection 23 extends from the connecting portion 22 toward the second side B in the axial direction.

The sleeve 20 may be fixedly connected to a generator shaft (not shown) by a screw thread. For this purpose, the sleeve 20 can have an internal thread, not shown, on the middle section 24 and an internal tooth 25 on the end section on the first side a. The pulley 10 may be rotatably supported at both axial ends on the sleeve 20 by a slide bearing 81 and a rolling bearing 82, respectively. The sleeve 20 may form an annular groove 26 on the radially outer surface of the projection 23 to receive the sliding bearing 81.

The torsion spring 30 and the wrap spring 40 constitute a series connection structure to transmit torque between the pulley 10 and the sleeve 20. The torsion spring 30 is configured as a helical torsion spring. The torsion spring 30 and the wrap spring 40 are disposed to extend coaxially along the axial direction of the pulley decoupler.

The torsion spring 30 is disposed axially around at least a portion of the shaft portion 21 of the sleeve 20. Both the torsion spring 30 and the wrap spring 40 are disposed radially between the pulley 10 and the shaft portion 21 of the sleeve 20. The wrap spring 40 is disposed radially between the pulley 10 and the torsion spring 30 and thus surrounds the torsion spring 30.

The first sleeve 50 may include a shaft portion 51 and a support portion 52. The shaft portion 51 extends in the axial direction and is disposed radially between the wrap spring 40 and the pulley 20. The support portion 52 extends radially inward from the shaft portion 51 and is disposed between the torsion spring 30 and the pulley 10. First sleeve 50 is disposed in the cavity of pulley 10 and is torsionally connected to pulley 10. For example, first sleeve 50 may be torsionally mounted in the cavity of pulley 10 by a press fit. According to an embodiment of the present invention, the support portion 52 of the first sleeve 50 is axially spaced apart from the protrusion 23 of the boss 20.

The second sleeve 60 includes a shaft portion 61 and a support portion 62. The shaft portion 61 extends in the axial direction and is disposed radially between the wrap spring 40 and the first sleeve 50. The support portion 62 extends radially inward from the shaft portion 61.

The torsion spring 30 abuts on the connecting portion 22 of the boss 20 at an end of the first side a and abuts on the supporting portion 62 of the second sleeve 60 at an end of the second side B. The wrap spring 40 abuts the support 52 of the first sleeve 50 at the end of the first side a and the support 62 of the second sleeve 60 at the end of the second side B.

End cap 70 may be connected to the end of pulley 10 on first side a, for example by a snap connection. An end cap 70 may cover an end of the sleeve 20 to isolate the sleeve 20 from the external environment on the first side a.

During operation of the pulley decoupler, torque introduced from the pulley 10 is introduced into the torsion spring 30 through friction between the first sleeve 50 and the wrap spring 40 and friction between the wrap spring 40 and the second sleeve 60. Thereafter, the torque is transmitted from the torsion spring 30 to the boss 20 through friction between the second sleeve 60 and the torsion spring 30 and friction between the torsion spring 30 and the connection portion 22 of the boss 20. The wrap-around spring 40 enables the generator shaft and the sleeve 20 fixed thereon to overrun the pulley 10 when the torque is reversed. In this state, the wrap spring 40 slides within the two

sleeves

50, 60 or one of the two sleeves.

In a pulley decoupler, lubricant is applied to the torsion spring 30, the wrap spring 40, the first sleeve 50 and the second sleeve 60, etc. to reduce wear between the spring and the sleeve. However, as the pulley decoupler operates, lubricant will flow from the interior to the end cap 70, as shown by path C in fig. 1. Lubricant leaks to the end cap 70 and possibly to the outside of the pulley decoupler. As a result, the springs and sleeves of the pulley decoupler are not sufficiently lubricated, which can affect the operation of the pulley decoupler and reduce its useful life.

The invention provides a seal for a pulley decoupler. FIG. 3 is a cross-sectional view of a pulley decoupler with a seal according to an embodiment of the invention. FIG. 4 is an enlarged partial view of a pulley decoupler according to an embodiment of the invention.

According to an embodiment of the present invention, a pulley decoupler may include a pulley 10, a hub 20, a torsion spring 30, a wrap spring 40, a first sleeve 50, a second sleeve 60, an end cap 70, and a seal 100. The structure of the pulley decoupler shown in fig. 3 and 4 is substantially the same as the pulley decoupler shown in fig. 1, except for the seal 100, and will not be described again.

According to an embodiment of the present invention, the seal 100 may be disposed between the support portion 52 of the first sleeve 50 and the protrusion 23 of the boss 20. In the exemplary embodiment, seal 100 is configured in a ring shape. In an exemplary embodiment, as shown in fig. 3 and 4, the seal 100 may include an engagement portion 110 and a sealing lip 120. The engagement portion 110 and the sealing lip 120 may be integrally formed.

In an exemplary embodiment, the engagement portion 110 of the seal 100 may be connected to the protrusion 23 of the shaft sleeve 20. The engagement portion 110 may form an interference fit with the protrusion 23 of the bushing 20. According to some embodiments of the invention, the seal 100 is an elastic seal and the engaging portion 110 is sleeved on the end of the protruding portion 23 facing the second side B by elastic deformation.

According to some embodiments of the invention, as shown in FIG. 4, the protrusion 23 of the bushing 20 may have a first surface 27 facing axially toward the first sleeve 50 and a second surface 28 facing radially toward the pulley 20. The joint 110 may have a stepped structure. Thus, the engagement portion 110 of the seal 100 may be disposed to engage both the first surface 27 and the second surface 28 of the protrusion 23.

The sealing lip 120 of the seal 100 may abut against a support portion 52 of the first sleeve 50, e.g. an axial surface of the support portion 52 facing the first side a. In some embodiments, the seal lip 120 is provided to extend obliquely toward the radially inner side from the joint portion 110. For example, the angle of inclination of the sealing lip 120 relative to the axis of rotation X may be between 45 and 60 degrees.

According to an embodiment of the present invention, the shaft sleeve 20, the first sleeve 50, the second sleeve 60, and the sealing member 100 may form a sealed annular housing in which the torsion spring 30 and the surrounding spring 40 are both disposed. Thereby, the lubricant can be retained in the annular accommodation chamber by the seal, so that leakage of the lubricant can be effectively prevented or reduced.

In an exemplary embodiment, the seal 100 is made of an elastomeric material. The elastic material may be a rubber material such as nitrile butadiene rubber, hydrogenated nitrile butadiene rubber, ethylene propylene diene monomer rubber, viton rubber, or the like.

The engagement portion 110 of the seal 100 is described above as being connected to the projection 23 of the sleeve 20 and the sealing lip 120 abuts the support portion 52 of the first sleeve 50. However, the present invention is not limited thereto. According to an embodiment of the present invention, the engagement portion 110 of the seal 100 may be connected to the support portion 52 of the first sleeve 50, and the seal lip 120 may abut against the protrusion 23 of the shaft sleeve 20.

The engaging portion 110 of the seal 100 is connected to the boss 20 by elastic deformation as described above. However, the present invention is not limited thereto. The engagement portion 110 of the seal 100 may also be attached to the sleeve 20 or the first sleeve 50 by screws, collars, adhesives, etc., in accordance with embodiments of the present invention.

While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the construction and methods of the embodiments described above. On the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements and method steps of the disclosed invention are shown in various example combinations and configurations, other combinations, including more, less or all, of the elements or methods are also within the scope of the invention.

Claims

1. A pulley decoupler comprising:

a pulley (10) comprising a cavity extending in an axial direction;

a bushing (20) coaxially and rotatably disposed in said cavity of said pulley (10), said bushing (20) comprising a protrusion (23);

a first sleeve (50) coaxially and torsionally arranged in said cavity of said pulley (10), said first sleeve (50) comprising a first support (52), said first support (52) being axially spaced from said protrusion (23); and

a seal (100) disposed between the first support (52) and the projection (23), wherein the seal (100) is configured in a ring shape and includes a joint (110) and a sealing lip (120), the joint (110) being connected to one of the first support (52) and the projection (23), and the sealing lip (120) being disposed against the other of the first support (52) and the projection (23).

2. The pulley decoupler as claimed in claim 1, wherein the engagement portion (110) of the seal (100) is connected to the projection (23) of the bushing (20) and the sealing lip (120) of the seal (100) is disposed against the first support (52) of the first sleeve (50).

3. The pulley decoupler as claimed in claim 2, wherein the engagement portion (110) of the seal (100) is fitted by elastic deformation on the end of the projection (23) of the bushing (20) facing towards the first support (52).

4. The pulley decoupler as claimed in claim 3, wherein said projection (23) of said bushing (20) has a first surface (27) axially facing said first sleeve (50) and a second surface (28) radially facing said pulley (20), said engagement portion (110) of said seal (100) having a stepped configuration to form an interference fit with said first and second surfaces (27, 28) of said projection (23), respectively.

5. The pulley decoupler as claimed in any one of claims 1-4, wherein the seal (100) is made of a rubber material.

6. The pulley decoupler as claimed in any one of claims 1-4, wherein the sealing lip (120) is arranged to extend obliquely from the engagement portion (110) towards a radially inner side.

7. The pulley decoupler of any one of claims 1-4, wherein the pulley decoupler has a first side (A) and a second side (B) that are axially opposite,

the sleeve (20) further comprises a first shaft portion (21) and a connecting portion (22), the first shaft portion (21) extending in an axial direction, the connecting portion (22) extending radially outward from an end of the first shaft portion (21) on the first side (A) to the protruding portion (23), the protruding portion (23) extending in an axial direction from the connecting portion (22) to the second side (B), and

the first sleeve (50) further includes a second shaft portion, the second shaft portion (51) extending in the axial direction and being disposed between the first shaft portion (21) and the pulley (10) in the radial direction, the first support portion (52) extending radially inward from the second shaft portion (51).

8. The pulley decoupler of claim 7, further comprising:

a torsion spring (30) disposed axially around at least a portion of the first shaft portion (21) of the sleeve (20);

a wrap spring (40) disposed radially between the pulley (10) and the torsion spring (30);

a second sleeve (60) including a third shaft portion (61) and a second support portion (62), wherein the third shaft portion (61) extends in an axial direction and is disposed radially between the wrap spring (40) and the first sleeve (50), the second support portion (62) extends radially inward from the third shaft portion (61), axial ends of the torsion spring (30) are supported on the connecting portion (22) and the second support portion (62) of the second sleeve (60), respectively, and axial ends of the wrap spring (40) are supported on the first support portion (52) of the first sleeve (50) and the second support portion (62) of the second sleeve (60), respectively; and

an end cap connected to an end of the pulley (10) at the first side (A).

9. The pulley decoupler of claim 8, wherein the bushing (20), the first sleeve (50), the second sleeve (60), and the seal (100) form a sealed annular pocket, wherein the torsion spring (30) and the wrap spring (40) are disposed in the annular pocket.