JP2006144812A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device capable of preventing a grease sealed therein from being deteriorated in a short period by suppressing the heating of a seal sliding part even under such use conditions that an outer ring is rotating at high speeds. <P>SOLUTION: This sealing device comprises a seal member 9 having a core 9a and an elastic seal 9b adhered to the core. The seal member 9 is fixed to the outer ring 7a which forms a rotating ring. The elastic seal 9b comprises a main lip 23 brought into contact with the side face of an annular groove 20 formed in an inner ring 7b when the outer ring is not rotated. The main lip 23 is formed to be displaced in a non-contact direction by a centrifugal force when the outer ring is rotated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sealing device suitably used in, for example, a pulley unit with a one-way clutch used in a belt drive starter and a rolling bearing used in high-speed rotation.

As a pulley unit with a one-way clutch used for a belt drive starter, the torque transmission between the shaft and the pulley is locked or free between the shaft and the pulley arranged concentrically around the shaft. A one-way clutch is provided, a rolling bearing is provided across the one-way clutch, and a seal member having a cored bar and an elastic seal bonded thereto at an axially outer end of the outer ring of the rolling bearing Is known (Patent Document 1).
JP 2003-176866 A

  According to the pulley unit with a one-way clutch, the outer ring may rotate at a high speed of 12000 to 15000 rotations / minute or more. In this case, heat generation at the seal sliding part increases, and the life of the grease sealed inside is increased. There was a problem that became shorter.

  An object of the present invention is to provide a sealing device that can suppress heat generation of the seal sliding portion even under use conditions where the outer ring rotates at a high speed, thereby preventing the life of the grease sealed inside from being shortened. It is to provide.

  The sealing device according to the present invention includes a sealing member including a cored bar and an elastic seal bonded thereto, and the sealing member is fixed to an outer ring serving as a rotating ring. It has a main lip that is brought into contact with a side surface of an annular groove provided in the inner ring, and the main lip is adapted to be displaced in a non-contact direction by centrifugal force during rotation of the outer ring. .

  The outer ring is an outer ring of a rolling bearing, an outer ring of a one-way clutch, a rotating wheel of a pulley, and the sealing device is a rolling bearing for outer ring rotation, a one-way clutch for outer ring rotation, a pulley unit with a one-way clutch for outer ring rotation, a pulley It is used for resin pulley devices and the like whose main body is made of resin and which incorporates rolling bearings on its inner periphery.

  A rolling bearing provided with a sealing device according to the present invention is arranged between an inner ring that is a fixed ring, an outer ring that is a rotating ring, a rolling element that is disposed between the central portions of both wheels, and at least one end of both wheels. In a rolling bearing having a cored bar and an elastic seal bonded thereto and fixed to the outer ring, the elastic seal of the sealing member is attached to the inner ring when the outer ring is not rotated. The main lip is brought into contact with a side surface of the annular groove provided, and the main lip is displaced in a non-contact direction by a centrifugal force when the outer ring rotates.

  The rolling bearing may be a double-sided seal bearing having the sealing device on both sides in the axial direction, and may be a single-side sealed bearing having the sealing device on one side in the axial direction.

  In such a rolling bearing, a one-way clutch is provided between a shaft and a pulley arranged concentrically around the shaft, and the rolling bearing is provided at least on one side in the axial direction of the one-way clutch. It is preferably used in a pulley unit with a clutch. In this case, the outer ring and inner ring of the rolling bearing may be integrated with the outer ring and inner ring of the one-way clutch, or may be separate from the outer ring and inner ring of the one-way clutch.

  In the sealing device according to the present invention, the interference between the side surface of the annular groove and the main lip when the outer ring is not rotated is about 0.04 to 0.40 mm. The main lip has such a shape that the interference is reduced (becomes light contact or non-contact) by centrifugal force when the outer ring rotates. When the outer ring is not rotating and when the outer ring is rotating at a low speed, the interference is maintained at a plus value, so that the sealing performance by the sealing member is ensured. During high-speed rotation of the outer ring, the internal grease moves to the inner periphery side of the outer ring by centrifugal force, and the moisture adhering to the seal member is also blown away by centrifugal force, so even if the interference is negative, the elastic seal and inner ring Only the labyrinth seal formed between the two can secure the sealing performance. The PV value (load x speed) of the seal is set to, for example, 24 Nm / s or less, and the main lip moves in the non-contact (pressing force and therefore load P is small) direction at high speed (the rotation speed and therefore the speed V is large). By doing so, a predetermined PV value or less can be maintained even during high-speed rotation.

  The elastic seal includes an adhesive portion covering the inner peripheral edge of the cored bar, an auxiliary lip provided at the inner end in the axial direction of the adhesive portion and facing the peripheral edge of the annular groove of the inner ring, and an adhesive portion. It has a connecting part in which a main lip is formed on the inner peripheral edge of the inner part in the axial direction. The main lip protrudes outward in the axial direction from the connecting part, and the main lip is separated from the side surface of the annular groove when centrifugal force acts. It is preferable to have a center-of-gravity balance design protrusion whose shape is determined so that a directional moment acts.

  The center-of-gravity balance design protrusion can be shaped to obtain an appropriate center-of-gravity balance by calculating the pressing force of the seal against changes in the number of rotations when the amount of protrusion and the position of the center of gravity are changed. For example, by increasing the center of gravity balance design protrusion so that the centrifugal force acting on the protrusion is greater than the centrifugal force acting on the axially inward portion of the main lip connection, etc. The main lip can be displaced away from the side surface of the annular groove.

  It is more preferable that a notch for facilitating movement of the connecting portion relative to the adhesive portion is provided in the adhesive portion of the elastic seal.

  This makes it possible to increase the amount of displacement of the main lip associated with the change in centrifugal force, suppresses the lift of the auxiliary lip that is not in contact with the centrifugal force, and reduces the sealing performance on the auxiliary lip side. Can be prevented.

  According to the sealing device of the present invention, heat generation of the seal sliding portion can be suppressed even under use conditions in which the outer ring rotates at high speed, thereby preventing the life of the grease sealed inside from being shortened.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the left and right refer to the left and right in FIG.

  1 and 2 show a pulley unit with a one-way clutch as an embodiment to which a sealing device according to the present invention is applied.

  A pulley unit (1) with a one-way clutch is arranged at a portion connecting an engine drive unit and a rotation shaft of a starter motor, and is a hollow shaft (3) fitted to the rotation shaft (2) of the starter motor. And a pulley (4) arranged concentrically therewith, a one-way clutch (5) is provided. On the outer periphery of the pulley (4), there is provided a belt spanning part on which a V-ribbed belt is spanned. The one-way clutch (5) is provided between the axial intermediate portion of the hollow shaft (3) and the axial intermediate portion of the pulley (4), and the left end portion of the hollow shaft (3) and the pulley (4 ) And the left end portion of the hollow shaft (3), and between the right end portion of the hollow shaft (3) and the right end portion of the pulley (4), rolling bearings (6) and (7) are respectively provided. The inner diameter part of the middle part of the pulley (4) also serves as the outer ring of the one-way clutch (5), and the outer diameter part of the middle part of the hollow shaft (3) also serves as the inner ring of the one-way clutch (5). Yes.

  The inner diameter of the pulley (4) is formed in a stepped shape in which the left and right end parts (large diameter part) (4a) (4b) are larger in diameter than the intermediate part (small diameter part) (4c). The outer diameter of 3) is the same except for the annular groove portion for the seal member (10).

  As shown in FIG. 2, the one-way clutch (5) includes a cam surface (11) provided on the inner peripheral surface of the intermediate portion of the pulley (4), and an intermediate between the cam surface (11) and the hollow shaft (3). The hollow shaft (3) is arranged in a wedge-shaped space (12) formed by the outer peripheral surface of the section, and the hollow shaft (3) and the pulley (4) are rotated relative to each other in one direction (locking direction). Roller (13) as a plurality of biting members that release between the pulley (4) and release the bite when rotated relative to the other direction (free direction) and the roller (13) in the biting direction ( A coil spring (14) as a biasing member that biases the wedge-shaped space (12) on the narrow side) and a cage (15) that positions the rollers (13) in the wedge-shaped space (12) are provided.

  The left and right rolling bearings (6) and (7) are ball bearings comprising outer rings (6a) and (7a), inner rings (6b) and (7b), balls (6c) and (7c), and cages (6d) and (7d), respectively. It is said that.

  The outer rings (6a) and (7a) of the left and right rolling bearings (6) and (7) have the outer diameters equal to the inner diameters of the left and right ends (4a) and (4b) of the pulley (4). The inner rings (6b) and (7b) are press-fitted into the left and right ends of the hollow shaft (3) with the inner diameter being equal to the outer diameter of the hollow shaft (3).

  Each of the rolling bearings (6) and (7) is a double-sided seal bearing having a sealing device according to the present invention, which will be described later, and an annular metal core (8a ) (9a) and annular seal members (8), (9) each comprising an annular elastic seal (8b) (9b) adhered thereto are disposed. The seal members (8) and (9) are made by elastically sealing the outer peripheral edge portions of the core bars (8a) and (9a) into the annular grooves provided in the inner diameters of the left and right end portions of the outer rings (6a) and (7a). The inner peripheral edges of (8b) and (9b) are brought into sliding contact with the inner rings (6b) and (7b).

  On the free end side of the pulley unit (the left end side in the figure), another seal member (10) is installed between the left end of the hollow shaft (3) and the pulley (4) to prevent muddy water from entering the pulley unit. ) Between the left end and

  As shown in FIG. 2, the cam surface (11) of the one-way clutch is provided with a plurality of sets (four sets in this embodiment) of the cam surfaces (11a) facing each other across the shaft center in the circumferential direction. It is configured. Each surface (11a) is not perpendicular to the normal passing through the center and axis of the roller (13), but has an acute angle slightly smaller than the right angle. At the end of each side (11a) of the cam on the wide side of the wedge-shaped space (12), there is provided a holding concave surface portion (16) for stopping the roller (13) receiving a centrifugal force with a circular cross section. ing.

  The cage (15) is made of synthetic resin and has an outer peripheral shape substantially along the cam surface (11) and an inner peripheral shape along the outer peripheral surface of the hollow shaft (3), and within the cam surface (11). It is press-fitted. A slight gap is provided between the inner diameter of the cage (15) and the outer diameter of the hollow shaft (3) to prevent the cage (15) and the hollow shaft (3) from contacting each other. Yes. The cage (15) is provided with a spring receiving recess (17) for positioning the coil spring (14). The spring receiving recess (17) is filled with grease having excellent meshing performance (particularly low-temperature meshing performance). The pillars located at the left and right ends of the cage (15) are radially inwardly projecting so as not to contact the inner end surfaces of the inner rings (6b) and (7b) of the left and right rolling bearings (6) and (7). 15a) and 15b are provided, and the radially inward protruding portions (15a) and (15b) form a labyrinth seal between the inner ends of the inner rings (6b) and (7b).

  The spring receiving recess (17) is connected to the roller holding concave portion (16) of the cam surface (11) and the spring positioning surface (18) provided on the inner periphery of the pulley (4) to The central axis direction is kept constant. The central axis of the coil spring (14) is such that when the centrifugal force acts on the coil spring (14), the coil spring (14) is deformed in a direction that reduces the biasing force against the roller (13). It is inclined with respect to the tangential direction. As with the cam surface (11), the spring positioning surface (18) of the pulley (4) is provided with a plurality of sets of two surfaces formed opposite to each other across the axis of the one-way clutch (5) in the circumferential direction. Is made up of.

  The spring receiving recess (17) includes a spring end positioning surface (17a) that prevents the coil spring (14) from moving in the spring axis direction, and the coil spring (14) moves inwardly perpendicular to the spring axis. And a spring positioning surface (18) of the pulley (4) that prevents the coil spring (14) from moving perpendicularly to the spring axis. It is a spring outer positioning surface for blocking. By these spring positioning surfaces (17a), (17b) and (18), the central axis of the coil spring (14) is kept perpendicular to the central axis of the roller (13). A roller holding inclined surface (17c) is provided continuously to the spring inner positioning surface (17b) of the spring receiving recess (17). The other end of the inclined surface (17c) has a slight gap with respect to the outer peripheral surface of the hollow shaft (3).

  The roller (13) indicated by a two-dot chain line in FIG. 2 shows a state when the centrifugal force is not working, and when the hollow shaft (3) is rotated counterclockwise in this state, (13) is caught between the hollow shaft (3) and the pulley (4), and the hollow shaft (3) and the pulley (4) rotate together. When the pulley (4) is rotated at a high speed and the rotation of the hollow shaft (3) is stopped, the roller (13) is subjected to a force in a direction along each surface (11a) of the cam. (13) moves to the wide side of the wedge-shaped space (12).

  Next, the sealing device according to the present invention will be described taking the right seal member (9) as an example. In the sealing device according to the present invention, as shown in FIG. 3, a seal member (9) composed of a core metal (9a) and an elastic seal (9b) is fixed to an outer ring (7a) serving as a rotating ring, and an elastic seal (9b) is an adhesive portion (21) covering the inner peripheral edge of the core metal (9a), and an annular groove (20) extending inward from the axially inner end of the adhesive portion (21). ) Auxiliary lip (22) facing the periphery without contact, and main lip (23) that is in contact with the inner surface of the annular groove (20) of the inner ring (7b) when the outer ring (7a) is not rotating, It has a connecting portion (24) in which a main lip (23) is formed on the inner peripheral edge of the adhesive portion (21) in the axially inward direction from the substantially central portion in the axial direction, and the main lip (23) As indicated by a chain line in the figure, the outer ring (7a) is displaced in a non-contact direction by a centrifugal force when rotating.

  In order to ensure that the main lip (23) is displaced in a non-contact direction by the centrifugal force when the outer ring rotates, the main lip (23) protrudes axially outward from the connecting portion (24). It has a center of gravity balance design protrusion (25), and a notch for easily moving the connecting part (24) relative to the adhesive part (21) in the adhesive part (21) of the elastic seal (9b) ( 26) is provided. The center of gravity balance design protrusion (25) is positioned radially outward from the center of gravity of the portion (23a) whose center of gravity is axially inward of the connecting portion (24) of the main lip (23). The main lip (23) is formed on the inner surface of the annular groove (20) when centrifugal force is applied, for example, by being relatively large with respect to the portion (23a) that is axially inward of the connecting portion (24). The shape is determined so that a moment in a direction away from the center acts.

  A bent portion (27) inclined inward in the axial direction is provided on the inner peripheral edge of the core metal (9a) so as to suppress the movement of the auxiliary lip (22) of the elastic seal (9b).

  When the outer ring (7a) rotates and centrifugal force is applied to the main lip (23), the main lip (23) is provided with an inner surface of the annular groove (20) due to the presence of the center of gravity balance design projection (25). Moment acts in the direction away from The connecting portion (24) is formed relatively thin, and since the notched portion (26) is provided in the bonding portion (21), the connecting portion (24) is not connected to the bonding portion (21). The main lip (23) is displaced in the direction indicated by the chain line as the outer ring (7a) rotates faster. The heat generation of the seal sliding part can be estimated by the PV value (load x speed). If the load (seal pressing force) does not change, the outer ring (7a) rotates at a high speed. As described above, the main lip (23) is displaced in the direction indicated by the chain line, so that the load P is reduced and can be suppressed to a predetermined PV value or less even during high-speed rotation.

  This one-way clutch-equipped pulley unit operates as follows.

  First, at the time of starting, the hollow shaft (3) integrated with the rotation shaft (2) of the starter motor is rotated counterclockwise. As a result, the hollow shaft (3) of the one-way clutch (5) rotates counterclockwise, and the roller (13) is engaged with the narrow side of the wedge-shaped space (12) of the one-way clutch (5), and the driving force Is transmitted, and the hollow shaft (3) and the pulley (4) of the one-way clutch (5) rotate together. The pulley (4) is connected to the crankshaft via a belt, and the engine is started by the rotation of the pulley (4). When the engine starts, the starter stops and the pulley (4) continues to rotate counterclockwise. As a result, the roller (13) is released and the state where only the pulley (4) rotates continues. In particular, when the engine rotates at high speed, the roller (13) is positioned by the concave surface portion (16) having substantially the same curvature as the roller (13), and is not in contact with the hollow shaft (3). Thus, at the time of starting, the roller (engagement member) (13) and the coil spring (biasing member) (14) rotate integrally with the pulley (4), and then the pulley (4) is rotated at a predetermined rotational speed. If it becomes above, only the pulley (4) will rotate and the energy loss accompanying the rotation of the part which does not contribute to the drive of an engine can be suppressed. Once the engine is started, the idle time during which only the pulley (4) rotates lasts from several tens of minutes to several hours, and during this time, the outer rings (6a) and (7a) of the rolling bearings (6) and (7) are rotated at high speed. . In the conventional sealing device, since the main lip is not moved in the non-contact direction by centrifugal force, the PV value increases as the rotation speed increases, which increases the heat generation of the seal sliding portion. However, in this pulley unit with a one-way clutch, the main lip (23) of the sealing device is displaced in a non-contacting direction, whereby an increase in PV value is suppressed, and an elastic seal (9b ) And grease contained inside are prevented.

  In the above embodiment, the outer ring of the one-way clutch (5) = the pulley (4) and the outer rings (6a) and (7a) of the rolling bearings (6) and (7) are separated from each other, and the one-way clutch (5 ) = Inner ring of hollow shaft (3) and inner ring (6b) (7b) of rolling bearing (6) (7) are separated, but outer ring of one-way clutch (5) and rolling bearing (6) The outer ring of (7) may be integrated, and the inner ring of the one-way clutch (5) and the inner ring of the rolling bearings (6) and (7) may be integrated. In this case, the seal members (8) and (9) are fixed to the end portion of the integrated outer ring (pulley).

  In addition, the sealing device and the rolling bearings (6) and (7) provided with the sealing device may be one-sided seals in which a sealing member is provided only on the outer side in the axial direction of the rolling bearings, instead of the illustrated both-side seals. It can be applied to other than the pulley unit with the direction clutch.

FIG. 1 is a longitudinal sectional view showing an embodiment of a pulley unit with a one-way clutch, which is an application example of a sealing device according to the present invention. FIG. 2 is a partially enlarged view of the same cross section. FIG. 3 is a partially enlarged view of a longitudinal section of the sealing device according to the present invention.

Explanation of symbols

(1) Pulley unit with one-way clutch
(3) Hollow shaft
(4) Pulley
(5) One-way clutch
(6) (7) Rolling bearing
(8) (9) Seal member
(8a) (9a) Core
(8b) (9b) Elastic seal
(13) Roll
(20) Annular groove
(21) Bonded part
(22) Auxiliary lip
(23) Main lip
(24) Connecting part
(25) Center of gravity balance design protrusion
(26) Notch

Claims (5)

  In a sealing device having a seal member made of a core metal and an elastic seal bonded thereto, and the seal member is fixed to an outer ring serving as a rotating ring, the elastic seal is an annular groove provided in the inner ring when the outer ring is not rotating. A sealing device having a main lip brought into contact with a side surface, the main lip being displaced in a non-contact direction by a centrifugal force when the outer ring rotates.   The elastic seal includes an adhesive portion covering the inner peripheral edge of the cored bar, an auxiliary lip provided at the inner end in the axial direction of the adhesive portion and facing the peripheral edge of the annular groove of the inner ring, and an adhesive portion. It has a connecting part in which a main lip is formed on the inner peripheral edge of the inner part in the axial direction. The main lip protrudes outward in the axial direction from the connecting part, and the main lip is separated from the side surface of the annular groove when centrifugal force acts. The sealing device according to claim 1, further comprising a protrusion for designing a center of gravity balance, the shape of which is determined so that a moment in the direction acts.   The sealing device according to claim 2, wherein a notch for facilitating movement of the connecting portion with respect to the adhesive portion is provided in the adhesive portion of the elastic seal.   In a rolling bearing comprising an inner ring that is a fixed ring, an outer ring that is a rotating ring, a rolling element that is disposed between the central portions of both wheels, and a sealing device that is provided between at least one end of both wheels. A rolling bearing, wherein the sealing device is any one of claims 1 to 3.   In a pulley unit with a one-way clutch, a one-way clutch is provided between a shaft and a pulley arranged concentrically around the shaft, and a rolling bearing is provided on at least one side of the one-way clutch in the axial direction. A pulley unit with a one-way clutch, wherein the bearing is the rolling bearing according to claim 4.

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