Timing belt tensioner with improved construction

Patent metadata

Field	Value
Publication number	US-11353092-B2
Application number	US-201816605971-A
Country	US
Kind code	B2
Filing date	May 1, 2018
Priority date	Apr 28, 2017
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

In an aspect, a tensioner is provided for an endless drive member, and includes a shaft-and-base unit, a tensioner arm, a pulley, and a tensioner spring. The shaft-and-base unit is mountable to be stationary relative to an engine, and includes a fastener aperture for a fastener. The tensioner arm is pivotable relative to the shaft-and-base unit about a tensioner arm axis. The pulley is rotatably mounted to the tensioner arm for rotation and is engageable with an endless drive member. The tensioner spring is positioned to urge the tensioner arm in a first direction relative to the shaft-and-base unit. The tensioner spring includes a plurality of coils that are arranged generally helically about a longitudinal axis and are spaced radially from one another and generally increase in distance away from the axis in a longitudinal direction.

First claim

What is claimed is:

1. A tensioner for an endless drive member, comprising:
a shaft-and-base unit that is mountable to be stationary relative to an engine, wherein the shaft-and-base unit includes a fastener aperture to permit a fastener to pass through to fixedly connect the shaft-and-base unit to the engine, and wherein the shaft-and-base unit includes a base and a shaft that is separate from the base and has the base mounted thereon, wherein the shaft has a shaft axis and has a first axial shaft end and a second axial shaft end, wherein the shaft has a radially outer surface that includes an arm support surface and which extends from the first axial shaft end to the second axial shaft end and is entirely free of any radial projections;
a tensioner arm that is pivotably supported on the arm support surface of the shaft for pivoting movement about a tensioner arm axis;
a pulley that is rotatably mounted to the tensioner arm for rotation about a pulley axis that is offset from the tensioner arm axis, wherein the pulley is engageable with an endless drive member; and
a tensioner spring that is positioned to urge the tensioner arm in a first direction relative to the shaft-and-base unit, wherein the tensioner spring has a first end, a second end and a plurality of coils between the first and second ends, wherein the first end is positioned to transfer torque with the base and the second end is positioned to transfer torque with the tensioner arm,
wherein the shaft includes an arm support portion that is cylindrical and which has the arm support surface thereon, and a shaft bottom at the first axial shaft end, wherein the shaft bottom has a proximal fastener aperture portion, and wherein the shaft is open at the second axial shaft end, wherein the shaft-and-base unit further includes a shaft cover that covers the second axial shaft end and includes an arm retaining portion that axially holds the tensioner arm on the shaft and that includes a distal fastener aperture portion and is movable on the second axial shaft end of the shaft to a position to bring the distal fastener aperture portion into alignment with the proximal fastener aperture portion to form the fastener aperture, wherein the shaft has a radially inner locating surface at the second axial shaft end and wherein the shaft cover has a radially outer locating surface that engages the radially inner locating surface on the shaft to locate the distal fastener aperture portion relative to the proximal fastener aperture portion.

2. A tensioner as claimed in claim 1 , wherein the tensioner arm is pivotably supported on the radially outer surface of the shaft via a bushing that is directly supported on the radially outer surface of the shaft.

3. A tensioner as claimed in claim 1 , wherein the shaft cover has a free arm stop thereon, and wherein the second axial arm end is on an axial projection having a first circumferential side that is a free arm stop engagement surface, wherein movement of the tensioner arm in the first direction brings the free arm stop engagement surface towards the free arm stop.

4. A tensioner as claimed in claim 3 , wherein the tensioner arm has an arm marker thereon at the second axial arm end, and wherein the shaft cover has a shaft marker thereon, wherein, during use, when the engine is off, the arm marker is aligned with the shaft marker.

5. A tensioner as claimed in claim 1 , wherein the pulley is a monolithic member that has a radially inner surface that is a first ball engagement surface, and wherein the tensioner further comprises:
an inner race that is press-fit on the pulley support surface and which includes a radially outer surface that is a second ball engagement surface; and
a plurality of balls that rotatably support the pulley on the inner race.

6. A tensioner as claimed in claim 1 , further comprising a damping carrier that includes a spring end engagement slot that is positioned to hold the second spring end, wherein the damping carrier further includes a radially inner damping surface thereon, and wherein the second spring end and the radially inner damping surface are positioned such that a tangential force on the second spring end during said torque transfer moves the damping carrier to bring the radially inner damping surface into frictional engagement or increased frictional engagement with the shaft-and-base unit.

7. A tensioner as claimed in claim 1 , wherein the plurality of coils are spaced from one another by a coil-to-coil gap, and wherein a space to enter between any two adjacent ones of the plurality of coils of the tensioner spring is less than a width of each of the plurality of coils so as to inhibit the tensioner spring from entangling with another identical tensioner spring.

8. A tensioner as claimed in claim 1 , wherein the plurality of coils are arranged generally helically about a longitudinal axis and are spaced radially from one another and generally increase in distance away from the axis in a longitudinal direction.

9. A tensioner for an endless drive member, comprising:
a shaft-and-base unit that is mountable to be stationary relative to an engine, wherein the shaft-and-base unit includes a fastener aperture to permit a fastener to pass through to fixedly connect the shaft-and-base unit to the engine;
a tensioner arm that is pivotable relative to the shaft-and-base unit about an arm pivot axis, wherein the tensioner arm has a first axial arm end and a second axial arm end, wherein the tensioner arm has a radially outer surface that includes a pulley support surface, and which extends from the first axial arm end to the second axial arm end and is entirely free of any radial projections;
a pulley that is rotatably supported on the pulley support surface of the tensioner arm for rotation about a pulley axis that is offset from the tensioner arm axis, wherein the pulley is engageable with an endless drive member;
a bushing that is positioned radially between the shaft-and-base unit and the tensioner arm to support the tensioner arm radially on the shaft-and-base unit; and
a tensioner spring that is positioned to urge the tensioner arm in a first direction about the tensioner arm axis; and
a carrier that is separate from but rotationally connected to the tensioner arm and to the tensioner spring, wherein the carrier extends radially outward beyond the pulley support surface on the tensioner arm, and cooperates with the shaft-and-base unit to at least partially enclose the tensioner spring.

10. A tensioner as claimed in claim 9 , wherein the shaft-and-base unit includes a base and a shaft that is separate from the base and has the base mounted thereon, wherein the shaft has a shaft axis and has a first axial shaft end and a second axial shaft end, wherein the shaft has a radially outer surface that includes an arm support surface and which extends from the first axial shaft end to the second axial shaft end and is entirely free of any radial projections,
and wherein the tensioner spring has a first end, a second end and a plurality of coils between the first and second ends, wherein the first end is positioned to transfer torque with the base and the second end is positioned to transfer torque with the tensioner arm.

11. A tensioner as claimed in claim 10 , wherein the tensioner arm is pivotably supported on the shaft via bushing that is directly supported on the arm support surface.

12. A tensioner as claimed in claim 10 , wherein the shaft includes an arm support portion that is cylindrical and which has the arm support surface thereon, and a shaft bottom at the first axial shaft end, wherein the shaft bottom has a proximal fastener aperture portion, and wherein

Assignees

• Litens Automotive Inc

Inventors

• Baljozovic Milos
• Comsa Rares I
• Dinca Flaviu V

Classifications

• F01L1/024 Primary

  Belt drive · CPC title

• F16H7/0831

  of the dry friction type · CPC title

• F16H2007/081

  Torsion springs · CPC title

• F16H7/1218 Primary

  of the dry friction type · CPC title

• F16H2007/0846

  comprising a mechanical stopper · CPC title