JP4364750B2 - Tensioner and labyrinth seal - Google Patents

Description

  The present invention relates to a tensioner that is used, for example, in a power transmission device of an internal combustion engine and adjusts the tension of a power transmission belt.

  Conventionally, as a tensioner provided in an internal combustion engine, a labyrinth is formed between a tensioner cup provided on a fixed side and a tensioner arm rotatably attached to the tensioner cup. That is, for example, an annular protrusion is provided along the opening edge of the tensioner cup, and an annular groove into which the annular protrusion is fitted is formed in the lid of the tensioner arm. According to the labyrinth configured in this manner, foreign matter such as dust or water from the outside of the tensioner is prevented from entering the tensioner cup, and the bearing of the tensioner is prevented from being worn or abnormal noise caused by the foreign matter is prevented. Is done.

However, when the tensioner is disposed in the vicinity of the tire house of the vehicle and is susceptible to external influences, there arises a problem that even if a labyrinth is provided, entry of foreign matter or water cannot be sufficiently prevented. Therefore, for example, as disclosed in Patent Document 1, it is conceivable to provide a seal member in a gap between the tensioner cup and the lid portion of the tensioner arm.
JP 2001-173737 A

  However, even if a seal member is provided in the labyrinth, if the tensioner arm is tilted due to the influence of the axial load, a gap is generated between the seal member and the tensioner arm or the tensioner cup, so that foreign matter or water can be completely prevented from entering. Cannot be prevented.

  An object of the present invention is to obtain a tensioner and a labyrinth seal that can more reliably prevent foreign matter or water from entering the tensioner cup.

  The first tensioner according to the present invention includes a tensioner cup, a tensioner arm, a spring, and a seal member. The tensioner cup is provided on the fixed side. The tensioner arm is provided so as to close the opening of the tensioner cup and is rotatable around the central axis of the tensioner cup, and has a lid portion formed with an annular groove into which the opening edge portion is fitted. A pulley is rotatably attached to the portion at a position eccentric from the central axis of the tensioner cup. The spring biases the tensioner arm in a direction to rotate around the central axis of the tensioner cup. The seal member is provided in the annular groove and is in sliding contact with the opening edge. Further, the seal member has an annular main body fitted into the annular groove, a ring concentric with the main body, a seal portion that is in sliding contact with the opening edge, and a connection portion that connects the main body and the seal portion, In a state where the tensioner arm is attached to the tensioner cup, the seal portion is substantially parallel to the main body.

  In the seal member, the connecting portion is located, for example, in the vicinity of the inner peripheral edge of the main body. In this case, in a state where the seal member does not receive external force, the distance between the seal portion and the main body is preferably increased as the distance from the connection portion increases.

  It is preferable that the thickness of the seal portion increases as the distance from the connection portion increases.

  The seal member may be fixed in the annular groove and slidably contact the opening edge. In this case, the width of the main body is preferably equal to the width of the annular groove.

  A plurality of tongue pieces that protrude in the radial direction and have flexibility may be provided along the circumferential direction of the main body at the outer peripheral edge and the inner peripheral edge of the main body, respectively. This facilitates attachment of the seal member to the first or second annular groove.

  The seal member is molded from a synthetic resin, for example.

  The second tensioner according to the present invention includes a tensioner cup, a tensioner arm, a spring, and a seal member. The tensioner cup is provided on the fixed side and has a first annular groove formed along the opening edge. The tensioner arm has a lid portion that is provided so as to close the opening of the tensioner cup and is rotatable around the central axis of the tensioner cup, and the lid portion has an annular shape that fits into the first annular groove. A protrusion and a second annular groove into which the opening edge fits are formed, and the pulley is rotatably attached at a position eccentric from the central axis. The spring biases the tensioner arm in a direction to rotate around the central axis of the tensioner cup. The seal member is provided in the first annular groove or the second annular groove, and is in sliding contact with the protrusion or the opening edge. The seal member includes an annular main body fitted into the first annular groove or the second annular groove, an annular concentric with the main body, a seal portion that is in sliding contact with the protrusion or the opening edge, and the main body. In the state where the tensioner arm is attached to the tensioner cup, the seal portion is substantially parallel to the main body.

  The labyrinth seal according to the present invention is configured by fitting an annular protrusion formed on the opening edge or the lid in an annular groove formed near the opening edge of the tensioner cup or on the lid of the tensioner arm. The labyrinth seal provided in the labyrinth, which has an annular main body fitted into the annular groove, a concentric annular shape with the main body, and a slidable contact with the projecting part or the opening edge, and the main body and the seal part are connected. In the state where the tensioner arm is attached to the tensioner cup, the seal portion is substantially parallel to the main body.

  According to the present invention, it is possible to more reliably prevent foreign matter or water from entering the tensioner cup.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of a tensioner according to an embodiment of the present invention.

  The tensioner cup 10 has a bottomed cylindrical shape, and the opening of the tensioner cup 10 is closed by the lid portion 41 of the tensioner arm 40. The tensioner arm 40 is rotatable around the central axis C of the tensioner cup 10. The tensioner arm 40 has a support shaft 42 at a position eccentric from the central axis C, and a pulley 43 that engages with a power transmission belt (not shown) is rotatably attached to the support shaft 42.

  The tensioner cup 10 has a flange 11, and a mounting hole 12 through which a bolt for fixing to a member such as an engine block or a fixed frame (not shown) is inserted. In the tensioner cup 10, a pivot bolt 13 extending along the central axis C is provided. The pivot bolt 13 is inserted into a cylindrical boss 15 that extends upward from the bottom 14 of the tensioner cup 10. The head 16 of the pivot bolt 13 is fixed to a recess 17 formed in the bottom 14 of the tensioner cup 10 via a bush 18. The pivot bolt 13 protrudes from the opening of the tensioner cup 10, and a hole 44 of the lid portion 41 of the tensioner arm 40 is fitted to the tip of the pivot bolt 13. That is, the tensioner arm 40 is rotatably supported by the pivot bolt 13. The recess 17 is closed by a cap 19.

  A damping mechanism 20 is provided inside the opening of the tensioner cup 10. The damping mechanism 20 includes an annular resin portion 21 and a metal portion 22. The cross section of the resin part 21 has an L shape, and the metal part 22 is fitted inside the resin part 21 and connected to the inner wall surface of the resin part 21. The resin portion 21 engages with a protrusion (not shown) formed on the lower surface of the lid portion 41. Therefore, when the pulley 43 is pressed by the power transmission belt and the tensioner arm 40, that is, the lid portion 41 rotates, the resin portion 21 and the metal portion 22 (that is, the damping mechanism 20) rotate integrally with the lid portion 41. The outer peripheral surface of the resin portion 21 is in sliding contact with the inner wall surface of the tensioner cup 10, and frictional resistance is generated by the rotation of the lid portion 41, and the swinging of the tensioner arm 40 is attenuated.

  The tensioner cup 10 is provided with a torsion coil spring 23 that urges the tensioner arm 40 in a direction to rotate around the central axis C. The upper end portion of the coil spring 23 is engaged with an engagement portion (not shown) formed on the lower surface of the metal portion 22, and the lower end portion of the coil spring 23 is an engagement portion (not shown) formed on the bottom portion 14 of the tensioner cup 10. To engage). Therefore, when the tensioner arm 40 swings, the coil spring 23 is twisted, and the spring force generated thereby is transmitted to the tensioner arm 40, and the tensioner arm 40 attempts to restore to the neutral position.

  The tensioner cup 10 is formed with a fitting groove 46 positioned outside the opening edge 45 and extending in an arc shape along the opening edge 45. That is, in the present embodiment, the fitting groove 46 does not surround the entire periphery of the opening edge 45, and when the tensioner cup 40 is viewed from the opening side, it has a shape in which the ring is interrupted. A protrusion 47 formed on the outer peripheral edge of the lid 41 is fitted in the fitting groove 46.

  An annular groove 48 into which the opening edge 45 is fitted is formed in the lid portion 41 of the tensioner arm 40. The inner peripheral wall of the annular groove 48 extends downward and contacts the resin portion 21 of the damping mechanism 20. That is, the labyrinth is configured by fitting the projection 47 into the fitting groove 46 and the opening edge 45 into the annular groove 48.

  A seal member 30 is provided at the bottom of the annular groove 48 (located above in FIG. 1). The seal member 30 is fixed in the annular groove 48 and is in sliding contact with the opening edge 45. Accordingly, foreign matter or the like that is about to enter the tensioner cup 10 from the outside of the tensioner is prevented from entering by the seal member 30 and does not reach the damping mechanism 20.

  The configuration of the seal member 30 will be described with reference to FIGS. 3 shows the seal member 30 as viewed from the right side of FIG.

  The seal member 30 has an annular main body 31 fitted to the bottom of the annular groove 48. The cross-sectional shape of the main body 31 matches the cross-sectional shape of the bottom of the annular groove 48. That is, the width of the main body 31 is equal to the width of the annular groove 48, and the main body 31 has two arc-shaped portions 31a and 31b as clearly shown in FIG. A seal portion 33 is coupled to the main body 31 via a connection portion 32. The seal portion 33 has an annular shape concentric with the main body 31, and is inclined inward by about 30 ° with respect to the main body 31 in a state where the seal member 30 is not assembled to the tensioner arm 40. In other words, the distance between the seal portion 33 and the main body 31 increases as the distance from the connection portion 32 increases in a state where the seal member 30 does not receive an external force.

  The connection part 32 is located in the vicinity of the inner peripheral edge part of the main body 31. The connection portion 32 is substantially perpendicular to the main body 31 and has an annular shape concentric with the main body 31. The connection part 32 is formed thinner than the main body 31. On the other hand, the thickness of the seal portion 33 increases as the distance from the connection portion 32 increases, and the portion connected to the connection portion 32 has substantially the same thickness as the connection portion 32.

  A plurality of tongue pieces 34 and 35 projecting in the radial direction and having flexibility are provided on the inner peripheral edge and the outer peripheral edge of the main body 31, respectively. The tongue piece 34 provided on the inner peripheral edge and the tongue piece 35 provided on the outer peripheral edge are provided at the same angular position with respect to the circumferential direction of the main body 31. In this embodiment, the tongue pieces 34 and 35 are provided every 60 °.

  The tongue pieces 34 and 35 are thinner than the other portions of the seal member 30, and in a state where the seal member 30 is attached to the annular groove 48 of the tensioner arm 40 (the state shown in FIG. 1), the tongue pieces 34 and 35 are substantially the same as the main body 31. It is bent so as to be vertical, and is in close contact with the inner peripheral wall surface or outer peripheral wall surface of the annular groove 48. Accordingly, when the seal member 30 is attached to the annular groove 48 in the tensioner assembling process, the seal member 30 does not fall out of the annular groove 48 even if the annular groove 48 is directed downward, and the assembling work is facilitated.

  In a state where the tensioner arm 40 is attached to the tensioner cup 10, the seal portion 33 of the seal member 30 is substantially parallel to the main body 31. In other words, the seal member 30 is elastically deformed into a U shape, and the seal portion 33 is elastically contacted with the opening edge portion 45 of the tensioner cup 10. As a result, even if water or foreign matter enters from the outside of the tensioner, the sealing member 30 prevents entry.

  During the operation of the tensioner, the tensioner arm 40 repeatedly swings with respect to the tensioner cup 10, and the seal portion 33 slides violently with respect to the opening edge 45. For this reason, the seal portion 33 is worn by the opening edge portion 45, but is formed so as to become thicker as it gets away from the connection portion with the connection portion 32, and the durability of the seal member 30 is ensured.

  The tensioner cup 10 and the tensioner arm 40 are formed of, for example, an aluminum alloy, and the seal member 30 is formed of a synthetic resin. In order for the sealing member 30 to maintain sufficient durability and to exhibit sealing performance, as a synthetic resin material, for example, an aliphatic polyketone or a polyether-based elastomer has a good elongation and has a calcium chloride solution resistance. It is preferable.

  In the above embodiment, the seal member 30 is provided in the annular groove 48 formed in the lid portion 41 of the tensioner arm 40. However, as a modified example, the seal member 30 may be provided in the tensioner cup 10. That is, the first annular groove is formed along the opening edge 45 of the tensioner cup 10, and the annular protrusion and the opening edge 45 that fit into the first annular groove are formed on the lid 41 of the tensioner arm 40. Is formed, and the seal member 30 may be provided in the first annular groove. Thus, the modified example is to form an annular groove in place of the fitting groove 47 of the above embodiment, and other configurations are basically the same as those of the above embodiment. That is, the seal member 30 includes an annular main body 31 fitted in the first annular groove, a seal portion 33 that is concentric with the main body and is in sliding contact with the protruding portion of the lid portion 41, and the main body 31 and the seal portion. The seal member 30 has the same shape and action as the above embodiment.

  As another modification, in the configuration in which the second annular groove formed in the lid portion 41 of the tensioner arm 40 is formed on the inner peripheral side of the opening edge portion 45 of the tensioner cup 10, the seal member 30 is the second Provided in the annular groove.

It is sectional drawing of the tensioner which is one Embodiment of this invention. It is a top view which shows a sealing member. It is the side view which looked at the sealing member from the right side of FIG. It is sectional drawing of the sealing member which follows the IV-IV line of FIG. 2 of a sealing member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tensioner cup 23 Spring 30 Seal member 31 Main body 32 Connection part 33 Seal part 34, 35 Tongue piece 40 Tensioner arm 41 Cover part 43 Pulley 45 Opening edge 48 Annular groove C Center axis

Claims (8)

A tensioner cup provided on the fixed side;
A lid portion formed so as to close the opening of the tensioner cup and rotatable around a central axis of the tensioner cup; and an annular groove into which an opening edge portion of the tensioner cup is fitted; A tensioner arm having a pulley rotatably attached to the lid portion at a position eccentric from the central axis;
A spring that urges the tensioner arm in a direction to rotate around a central axis of the tensioner cup;
A seal member provided in the annular groove and in sliding contact with the opening edge;
The sealing member is connected to the annular body is fitted to the annular groove exhibits said body concentric with annular, and the seal portion slidably contacting with the opening edge portion, the main body and the seal portion, said body and a connecting portion located in the vicinity of the inner peripheral edge portion of,
The thickness of the seal portion increases as the distance from the connection portion increases.
In a state in which the tensioner arm is attached to the tensioner cup, the sealing portion, wherein the Ri Do the flat row with respect to the main body, that Sessu bullet to the opening edge tensioner. Wherein in a state where the sealing member is not subjected to an external force, the distance between the body and the sealing portion according to claim 1, characterized in that the larger the distance from the connecting portion tensioner.   The tensioner according to claim 1, wherein the seal member is fixed in the annular groove and slidably contacts the opening edge.   The tensioner according to claim 1, wherein a width of the main body is equal to a width of the annular groove.   2. The tensioner according to claim 1, wherein a plurality of tongue pieces protruding in a radial direction and having flexibility are respectively provided along a circumferential direction of the main body at an outer peripheral edge and an inner peripheral edge of the main body.   The tensioner according to claim 1, wherein the seal member is molded from a synthetic resin. A tensioner cup provided on the fixed side and having a first annular groove formed along the opening edge;
The lid has a lid portion that is provided so as to close the opening of the tensioner cup and is rotatable around a central axis of the tensioner cup, and the lid portion has an annular shape that fits into the first annular groove. A tensioner arm in which a protrusion and a second annular groove into which the opening edge portion is fitted are formed, and a pulley is rotatably attached at a position eccentric from the central axis;
A spring that urges the tensioner arm in a direction to rotate around a central axis of the tensioner cup;
A seal member provided in the first annular groove or the second annular groove and in sliding contact with the protrusion or the opening edge;
The seal member includes an annular main body fitted into the first annular groove or the second annular groove, a seal portion that is concentric with the main body and is in sliding contact with the protrusion or the opening edge. , Connecting the main body and the seal portion, and having a connection portion located in the vicinity of the inner peripheral edge of the main body ,
The thickness of the seal portion increases as the distance from the connection portion increases.
In a state in which the tensioner arm is attached to the tensioner cup, the sealing portion, wherein the Ri Do the flat row with respect to the main body, that Sessu bullet to the opening edge tensioner. A labyrinth provided in a labyrinth formed by fitting the annular protrusion formed on the opening edge or the lid in the annular groove formed near the opening edge of the tensioner cup or on the lid of the tensioner arm. A seal,
An annular main body fitted into the annular groove;
A seal portion that exhibits a concentric annular shape with the main body and is in sliding contact with the protrusion or the opening edge;
Connecting the main body and the seal part, and having a connection part located in the vicinity of the inner peripheral edge of the main body ,
The thickness of the seal portion increases as the distance from the connection portion increases.
In a state in which the tensioner arm is attached to the tensioner cup, the sealing portion is Ri Do the flat row with respect to the body, labyrinth seal, characterized in Rukoto that Sessu bullet to the opening edge.

Images