JP2009156273A - Bearing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing structure positively preventing an increase in rotational resistance of a tensioner pulley and damage near a contact portion of an end of a lip by eliminating suction of the tip end of the lip upon air inside a labyrinth space contracting at low temperatures. <P>SOLUTION: In this bearing structure, the labyrinth space 251 for communicating a holding space 250 between both inner and outer ends in the direction of a shaft 23 of an inner race 241 and an outer race 242, with the outside via an opening part of a seal material 246 is formed between a slinger 247 and the seal material 246 facing each other in the direction of the shaft 23. The seal material 246 is integrally provided with the lip 252 extending diagonally outward in the radial direction so as to contact the slinger 247, and air-tightly sealing the labyrinth space 251 from the outside. Through-holes 253 communicated with the outside in a range where intrusion of water into the labyrinth space 251 from the outside is suppressed, are provided at four locations in the lip 252 at prescribed intervals in the circumferential direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing structure that rotatably supports a pulley with respect to a shaft.

  In general, various auxiliary machines such as an alternator, a power steering pump, an air conditioner compressor, and a water pump each have a pulley that is integrally connected to a shaft and wound around a crank pulley on one end side of the crankshaft. Each belt is driven by being wound around a pulley of each shaft. In this case, each shaft is rotatably supported by a casing of various auxiliary machines via a bearing such as a ball bearing.

  In the case of a ball bearing or the like, the ball bearing is directly attached to the shaft. Therefore, in order to prevent foreign matter or water from entering the ball bearing, the inner race and the outer race of the ball bearing are prevented from entering. A pair of sealing materials that seal the space from the outside (outside the space) in a sealed state is provided in the space between the both ends of the ball bearing in the shaft direction (for example, Patent Documents). 1).

  By the way, the belt that is wound around the pulley of the various auxiliary machines from the crank pulley is also wound around the tensioner pulley in order to smoothly drive the various auxiliary machines, and this tensioner pulley is fixed to the tensioner arm. The shaft is rotatably supported via a bearing.

In such a case, even in such a bearing, it is necessary to prevent intrusion of foreign matter or water. From this point, a shaft side member attached to the shaft side and a pulley side member attached to the pulley side are conventionally required. A labyrinth space communicating with the bearing is formed between the two and the labyrinth space is provided with a seal member that seals the labyrinth space from the outside (outside the labyrinth space) in a sealed state (for example, Patent Document 2). In this case, the seal member is fixed to the pulley side member and seals the labyrinth space by contacting the shaft side member.
Japanese Utility Model Publication No. 63-86424 JP-A-5-322005

  However, in the above conventional one, the labyrinth space between the shaft side member and the pulley side member is sealed in a sealed state by the seal member. Then, the contact end side of the seal member fixed to one of the shaft side member and the pulley side member (pulley side member) is adsorbed to the other (shaft side member). If the pulley rotates in this state, the rotational resistance of the pulley increases and the vicinity of the contact portion of the seal member may be damaged.

  The present invention has been made in view of the above points, and an object of the present invention is to eliminate the adsorption of the seal member when the air in the labyrinth space contracts at a low temperature, thereby increasing the rotational resistance of the pulley and the seal member. It is an object of the present invention to provide a bearing structure capable of reliably preventing damage in the vicinity of the contact portion.

  In order to achieve the above object, the present invention presupposes a bearing structure that rotatably supports a pulley with respect to a shaft, and a shaft side member attached to the shaft side and a pulley side member attached to the pulley side. A labyrinth space communicating with the bearing is formed between the two. Further, a seal member is provided on one of the shaft side member and the pulley side member so as to extend in contact with either the pulley side member or the shaft side member and seal the labyrinth space from the outside in a sealed state. ing. Then, the seal member has an opening that opens to the outside within a range that can prevent water from entering the labyrinth space, for example, a plurality of communication holes that communicate inward and outward with respect to the labyrinth space, or A slit or the like opening at the tip is provided so as to communicate with the labyrinth space in the inner and outer directions.

  With this specific matter, the seal member that seals the labyrinth space between the shaft-side member and the pulley-side member in a sealed state communicates with the outside in a range that can prevent water from entering the labyrinth space (outside the labyrinth space). Since openings such as a plurality of communication holes and slits are provided, it is possible to effectively prevent foreign matters and water from entering the bearing (in the labyrinth space).

  In this case, when the air in the labyrinth space contracts at a low temperature, external air is introduced into the labyrinth space through the opening, and the inside of the labyrinth space does not become negative pressure. For this reason, the seal member is prevented from adsorbing to the shaft-side member or the pulley-side member that the tip of the seal member contacts and seals. As a result, the rotational resistance when the pulley rotates can be suppressed to a small level, and damage near the contact portion of the seal member can be reliably prevented.

  In particular, when a slit that connects the inside and outside of the labyrinth space is applied as the opening at the tip of the seal member, the opening (slit) is not easily blocked by the surface tension of water adhering to the seal member. Sometimes, when air in the labyrinth space contracts, it is possible to smoothly introduce air from the outside into the labyrinth space through the opening.

  In short, in short, the seal member that seals the labyrinth space between the shaft-side member and the pulley-side member in a sealed state has a plurality of communication holes that communicate with the outside within a range that can prevent water from entering the labyrinth space. By providing an opening such as a slit, it is possible to effectively prevent foreign matter and water from entering the bearing (in the labyrinth space). And when the air in the labyrinth space contracts at a low temperature, external air is smoothly introduced into the labyrinth space through the opening, the negative pressure in the labyrinth space is suppressed, and the adsorption of the seal member is prevented. The rotation resistance when the pulley rotates can be suppressed to a low level, and damage near the contact portion of the seal member can be reliably prevented.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of an engine in which the structure of a bearing according to Embodiment 1 of the present invention is applied to an arm of a belt tensioner, and 11 is a crankshaft whose front end projects forward from the engine 1. A crank pulley 111 is connected to the front end of the shaft 11 so as to rotate together. Further, the axial end of various auxiliary machines such as an alternator 12, a power steering pump 13, an air conditioner compressor 14, and a water pump 15 are positioned at substantially the same vertical position as the forward projecting position of the crank pulley 111 from the engine 1. An alternator pulley 121, a power steering pump pulley 131, an air conditioner compressor pulley 141, and a water pump pulley 151, which are integrally connected to 12a, 13a, 14a, and 15a, are arranged. On the front surface side of the engine 1, a crank pulley 111 at the front end of the crankshaft 11, an alternator pulley 121, a power steering pump pulley 131, an air conditioner compressor pulley 141, a water pump pulley driven by the crank pulley 111, respectively. 151 and a serpentine wound around each pulley 111, 121, 131, 141, 151 and driven to rotate the pulleys 121, 131, 141, 151 of the various auxiliary machines 12, 13, 14, 15 by driving rotation of the crank pulley 111. A belt 16 is provided.

  A belt tensioner 2 that adjusts the tension of the serpentine belt 16 is disposed on the front surface side of the engine 1. The belt tensioner 2 includes a tensioner pulley 21 (pulley) and an arm 22. The arm 22 is pivotally supported by the tensioner main body 20 so that the tensioner pulley 21 is pivotally supported by the tip of the arm 22. The arm 22 is urged in a direction indicated by an arrow in FIG. 1 by a spring (not shown) built in the tensioner body 20. The tensioner pulley 21 is wound around a stretched portion of the serpentine belt 16 located between the crank pulley 111 and the power steering pump pulley 131, and is applied to the serpentine belt 16 according to the swing of the arm 22 of the belt tensioner 2. Tension is applied.

  2 and 3, the tensioner pulley 21 includes an outer peripheral cylindrical portion 211 around which the serpentine belt 16 is wound, and a substantially annular shape inside the outer peripheral cylindrical portion 211. The inner peripheral side cylindrical portion 213 is provided integrally with the connecting portion 212. Further, the tensioner pulley 21 is rotatably supported via a bearing 24 on a shaft 23 protruding forward (left side in FIG. 2) from the tip of the arm 22. The bearing 24 includes an inner race 241 whose inner peripheral surface is integrally connected to the shaft 23, an outer race 242 whose outer peripheral surface is integrally connected to the inner peripheral cylindrical portion 213 of the tensioner pulley 21, and an inner race. .. And outer balls 244, 244,..., Which are rotatably arranged at seven circumferentially equal intervals, respectively, at two locations inside and outside the shaft 23 between the outer race 242 and the outer race 242. Yes. Further, the bearing 24 includes cages 245 and 245 for individually holding the inner balls 243, 243,... And the outer balls 244, 244,... At two locations inside and outside the shaft 23 between the inner race 241 and the outer race 242. I have. Each inner ball 243 and each outer ball 244 are accommodated between the inner race 241 and the outer race 242 while being held by the cage 245, and in this state, the inner peripheral side tubular portion 213 of the tensioner pulley 21. The bearing 24 is attached to the tensioner pulley 21 by being press-fitted into the tensioner pulley 21. The tensioner pulley 21 into which the bearing 24 is press-fitted is positioned by contacting the inner peripheral surface of the inner race 241 through the shaft 23 protruding from the tip of the arm 22 and abutting against a step portion 231 provided at the base of the shaft 23. The inner race 241 is rotatably connected to the shaft 23 by a nut N that is screwed to the tip of the shaft 23 to enable rotation support to the shaft 23. For the sake of convenience, the inner side and the outer side in the direction of the shaft 23 are referred to as the inner side (the right side in FIG. 2) and the outer side (the left side in FIG. 2) as the outer side.

  In addition, step portions 241a and 241b in which the diameters of the outer peripheral surfaces at the inner and outer end portions are slightly reduced are provided at both inner and outer end portions (both ends in the shaft 23 direction) on the outer periphery side of the inner race 241. On the other hand, step portions 242a and 242b in which the diameters of the inner peripheral surfaces at the inner and outer end portions are slightly enlarged are provided at both inner and outer end portions (both end portions in the shaft 23 direction) on the inner periphery side of the outer race 242. The bearing 24 includes a pair of inner and outer annular seal members 246 and 246 as pulley-side members attached to the tensioner pulley 21, and a pair of inner and outer annular slinger 247 and 247 as shaft members attached to the shaft 23. It has. The outer end portions of the sealing materials 246 and 246 are press-fitted and attached to the step portions 242a and 242b at both the inner and outer end portions of the outer race 242, respectively.

  As shown in FIG. 4, the sealing materials 246 and 246 (shown only on the outer side in FIG. 4) are an annular plate-shaped core material 246a made of synthetic resin, and acrylic vulcanized around the core material 246a. A rubber material 246b made of rubber is provided, and the inner end portion of the rubber material 246b contacts and seals the vertical surfaces of the step portions 241a and 241b at the inner and outer end portions of the inner race 241 respectively. The inner ends of slinger 247 and 247 are press-fitted and attached to the step portions 241 a and 241 b at both the inner and outer ends of the inner race 241, respectively. The slinger 247, 247 (only the outer one is shown in FIG. 4) includes an annular plate-shaped core material 247a made of synthetic resin, and a rubber material 247b made of supernitrile vulcanized on the outer surface of the core material 247a. I have. In this case, an opening such as a slit or a communication hole (not shown) is provided at the inner end of the rubber member 246b of each sealing member 246, and the space between the inner race 241 and the outer race 242 of the bearing 24, that is, the inner race. The holding spaces 250 of the inner balls 243 and the outer balls 244 between the inner and outer ends of the shaft 241 and the outer race 242 are communicated to the outside (outside the holding space 250) through the openings. The inner slinger 247 has an outer end of the outer slinger 247 because the inner end (right end in FIG. 2) of the inner peripheral tubular portion 213 of the tensioner pulley 21 is slightly protruded radially inward. The diameter is smaller than the diameter.

  The slinger 247 on the outer side (left side in FIGS. 2 and 4) is disposed so as to cover the outer sealing material 246 from the outer side in the shaft 23 direction, while on the inner side (right side in FIGS. 2 and 4). The slinger 247 is disposed so as to cover the inner sealing material 246 from the inner side in the shaft 23 direction. In this way, between the outer slinger 247 and the outer seal member 246 and between the inner slinger 247 and the inner seal members 246 and 246 that face each other in the direction of the shaft 23, there is an inner race in the bearing 24. Labyrinth spaces 251 and 251 are formed to allow the holding space 250 between the inner and outer ends of the shaft 241 and the outer race 242 to communicate with each other through the openings of the seal members 246. Further, the inner and outer seal members 246 and 246 (rubber members 246b and 246b) are respectively provided with labyrinth spaces 251 and 251 extending radially outward so as to contact the inner and outer slinger 247 and 247, respectively. Lips 252 and 252 are integrally provided as sealing members for sealing from the outside (outside the labyrinth space 251). Then, as shown in FIG. 5, the lip 252 has four locations at predetermined intervals in the circumferential direction (approximately every 90 °) to the outside within a range that can prevent water from entering the labyrinth spaces 251 from the outside. Communication holes 253, 253,... Are provided as openings that open. Each communication hole 253 communicates with each labyrinth space 251 in the inner and outer directions of the shaft 23.

  Therefore, in the first embodiment, the labyrinth space 251 that communicates the holding space 250 inside the bearing 24, that is, between the inner and outer ends of the inner race 241 and the outer race 242 in the shaft 23 direction, through the openings of the seal members 246. Four communication holes 253, 253,... Communicating with the lip 252, 252 for sealing the 251 in a sealed state are communicated to the outside within a range in which the entry of water from the outside (outside the labyrinth space 251) to each labyrinth space 251 can be suppressed. Since it is provided, it is possible to effectively prevent foreign matters and water from entering the bearing 24 (in the labyrinth spaces 251 and 251).

  In that case, when the air in the labyrinth spaces 251 and 251 contracts at a low temperature, external air is introduced into the labyrinth spaces 251 and 251 through the communication holes 253, and the inside of the labyrinth spaces 251 and 251 becomes negative pressure. There is no. For this reason, the lips 252 and 252 are prevented from adsorbing to the inner and outer slinger 247 and 247 that are contacted and sealed at the tip. Thereby, the rotation resistance when the tensioner pulley 21 rotates can be suppressed to a small level, and damage near the contact portion of the lips 252 and 252 can be reliably prevented.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the opening that opens in the lip is changed. The other configurations except for the opening are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  That is, in this embodiment, as shown in FIG. 6, as an opening that opens at the tip of the lips 252 and 252 so as to communicate with the labyrinth spaces 251 and 251 (only the outer side is shown in FIG. 6) in the inner and outer directions. The slit 254 is provided. The slit 254 is formed only at one place in the circumferential direction at the tips of the lips 252 and 252. The labyrinth spaces 251 and 251 communicate with the outside (outside the labyrinth space 251) through the slits 254 and 254 in a state where the tips of the lips 252 and 252 are in contact with the inner and outer slinger 247 and 247. The slits 254 are cut out to almost half the length toward the bases of the lips 252 and 252 so that the air introduced through the slits 254 can be easily guided into the labyrinth space 251.

  Therefore, in the second embodiment, when the air in the labyrinth spaces 251 and 251 contracts at a low temperature, external air is introduced into the labyrinth spaces 251 and 251 through the slits 254 at the tips of the lips 252 and 252, 251 and 251 do not become negative pressure. For this reason, the lips 252 and 252 are prevented from adsorbing to the inner and outer slinger 247 and 247 that are contacted and sealed at the tip. Thereby, the rotation resistance when the tensioner pulley 21 rotates can be suppressed to a small level, and damage near the contact portion of the lips 252 and 252 can be reliably prevented.

  In addition, slits 254 and 254 for connecting the labyrinth spaces 251 and 251 to the inside and outside are provided at the tips of the lips 252 and 252 provided integrally with the inner and outer sealing materials 246 and 246 (rubber materials 246b and 246b). Therefore, the openings (slits 252 and 252) are not easily blocked by the surface tension of water attached to the lips 252 and 252, and the slits 252 and 252 are opened when the air in the labyrinth spaces 251 and 251 contracts at low temperatures. The air can be smoothly introduced into the labyrinth spaces 251 and 251 through the outside.

  In addition, this invention is not limited to said each Example, The other various modifications are included. For example, in the second embodiment, the slits 254 are provided at the tips of the lips 252 and 252 so that the slits 254 are cut out to almost half the length toward the base, but as shown in FIG. 8, the tips of the lips 252 and 252 are provided. Further, the minimum necessary slit 255 (opening) cut out substantially parallel to the contact surfaces of the inner and outer slinger 247, 247 may be used.

  In each of the above-described embodiments, the case where the present invention is applied to the bearing 24 of the tensioner pulley 21 has been described. However, the present invention is not limited to this and may be a bearing such as an idler pulley.

It is a front view of the engine which shows the layout of various auxiliary machines at the time of using the structure of the bearing concerning Example 1 of this invention for a tensioner pulley. It is a vertical side view of a tensioner pulley. It is the front view of a tensioner pulley similarly seen from the shaft direction front side. It is an enlarged sectional view near the lip of the sealing material. It is the front view of the sealing material similarly seen from the slinger side. It is an expanded sectional view of lip vicinity of the sealing material using the structure of the bearing concerning Example 2 of this invention. It is the front view of the sealing material similarly seen from the slinger side. It is an expanded sectional view of the lip vicinity of the sealing material using the structure of the bearing which concerns on the modification of Example 2 of this invention.

Explanation of symbols

21 Tensioner pulley (pulley)
23 Shaft 24 Bearing 246 Inner and outer sealing material (pulley side member)
247 Inner and outer slinger (shaft side member)
251 Labyrinth space 252 Lip (seal member)
253 communication hole (opening)
254 slit (opening)
255 slit (opening)

Claims (3)

A bearing structure that rotatably supports a pulley with respect to a shaft,
A labyrinth space communicating with the bearing is formed between the shaft side member attached to the shaft side and the pulley side member attached to the pulley side,
One of the shaft side member and the pulley side member is provided with a seal member that extends so as to contact either the pulley side member or the shaft side member and seals the labyrinth space from the outside in a sealed state. And
The bearing structure according to claim 1, wherein the seal member is provided with an opening that opens to the outside in a range in which entry of water from the outside into the labyrinth space can be suppressed. In the structure of the bearing according to claim 1,
As the opening, a plurality of communication holes provided in the seal member are applied so as to communicate with the labyrinth space in the inner and outer directions. In the structure of the bearing according to claim 1,
The structure of the bearing characterized in that a slit that opens at the tip of the seal member is applied as the opening so as to communicate with the labyrinth space in the inner and outer directions.

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