JP2016160943A - Bearing for pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing for a pulley which can prevent the intrusion of water and foreign matters into the bearing even if under such a condition as washing by high-pressure washing water, bad road traveling or the like, is excellent in seal performance, and simple in structure.SOLUTION: A seal member 30 for sealing both-end opening parts of a bearing space which is formed between opposing parts of an outer ring 21 and an inner ring 22 is formed of an annular elastic seal plate 31 whose external peripheral part is supported by seal attachment grooves 26 which are formed at both ends of an inside diameter face of the outer ring, and a cross-section circular elastic ring 38 which is spliced to a single-face internal peripheral part of the seal plate 31. A tapered face 27 fastened by the elastic ring 38 is formed over both ends of the outside diameter face of the inner ring 22, the elastic ring 38 is made to elastically contact with the single-face internal peripheral part of the seal plate 31 by an axial component force which is imparted to the elastic ring 38 by the fastening of the tapered face 27, and both a contact part between the elastic ring 38 and the seal plate 31 and a contact part between the elastic ring 38 and the tapered face 27 are sealed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pulley bearing in an automobile engine.

  In belt transmissions that drive automotive accessories such as alternators and compressors, the belt movement is guided by idler pulleys, or the tension pulley is pressed against the belt by a hydraulic auto tensioner to absorb belt tension fluctuations. ing.

  The idler pulley and the tension pulley as described above are generally supported rotatably by a unitized bearing incorporated on the inner diameter side of the boss portion. When the pulley unit with a bearing is installed in a belt transmission device, if the bearing is exposed to the outside, foreign matter such as incoming muddy water can easily enter the bearing, and the foreign matter can quickly damage the bearing. I will let you.

  Therefore, a bearing with a seal is generally adopted as the pulley bearing. However, since the foreign matter comes into direct contact only with the bearing seal, the bearing seal is easily damaged, and there is a problem in durability.

  Here, as in the pulley bearing device described in Patent Document 1, it is possible to improve water resistance by providing slinger on both sides of the bearing that rotatably supports the pulley body. When the outer peripheral portion is in contact with the outer ring of the bearing, it becomes rotational resistance of the outer ring that rotates together with the pulley body. Therefore, the outer peripheral portion of the slinger needs to be spaced apart from the side surface of the outer ring.

  For this reason, when the engine room is washed with high-pressure washing water, the high-pressure washing water may enter between the slinger and the opposed portion of the bearing seal through a gap formed between the opposed surfaces of the slinger and the outer ring. At this time, in the contact-type bearing seal in which the lip is brought into contact with the inner ring, the permeation amount of the lip is small, so that it is not possible to completely prevent water from entering the bearing.

  Therefore, as described in Patent Document 2, a slinger is press-fitted into the inner ring, and a secondary seal lip is provided on the axial base surface facing the slinger of the sliding seal part whose outer peripheral part is supported by the outer ring. By bringing the tip of the seal lip into elastic contact with the slinger, it is possible to prevent the sliding seal part from being damaged and to prevent high pressure cleaning water from entering.

JP 2005-337383 A JP 2009-216138 A

  By the way, in the sealing device for a bearing with a slinger described in Patent Document 2, since the water resistance is not sufficient only by the sub seal lip, a main seal lip is provided at the inner peripheral edge of the sliding seal portion. The seal lip is elastically brought into contact with the end portion in the axial direction of the step portion formed at the end portion of the inner ring so as to improve the water resistance with a double seal structure with the sub seal lip. At this time, it is necessary to form a stepped portion on the inner ring, and it is necessary to process the axial end surface with which the main seal lip of the stepped portion is in elastic contact with high precision, which takes time and labor to process the inner ring. There is.

  Further, since the secondary seal lip and the main seal lip maintain the sealing performance by elastic contact, they are easily worn and cannot maintain a good sealing performance over a long period of time.

  In recent years, conditions such as running on rough roads, which have not been considered in the past, have increased, and foreign matter has been infiltrated into the bearing only with slinger countermeasures. As a result, the water resistance requirement of pulley bearings has increased. ing.

  An object of the present invention is to provide a pulley with a simple structure excellent in sealing performance that can prevent water and foreign matter from entering the inside of the bearing even under conditions such as washing with high-pressure washing water and traveling on rough roads. It is to provide a bearing for an automobile.

  In order to solve the above problems, in the present invention, a rolling element is incorporated between the outer ring and the inner ring, and each opening at both ends of the bearing space formed between the opposed parts of the outer ring and the inner ring is sealed by incorporating a seal member. In the pulley bearing, the seal member has an annular elastic seal plate whose outer peripheral portion is supported by seal mounting grooves formed at both ends of the inner surface of the outer ring, and an inner peripheral portion on one side of the seal plate. Attached to the elastic ring with a circular cross section, provided at both ends of the outer diameter surface of the inner ring are tapered surfaces that are tightened by the elastic ring, and an axial component force applied to the elastic ring by tightening the tapered surface Thus, a configuration is adopted in which the elastic ring is brought into elastic contact with the inner peripheral portion of one side of the seal plate.

  In the pulley bearing configured as described above, the sealability in the axial direction is maintained by the elastic contact of the elastic ring with the seal plate, and the sealability in the radial direction is maintained by the elastic contact of the elastic ring with the tapered surface.

  When the elastic ring wears due to contact with the seal plate, the elastic ring moves to the small diameter end side along the tapered surface, and maintains a contact state with the seal plate and the tapered surface. Maintained.

  Here, the tapered surface has an inward slope that applies an inward axial component force to the elastic ring disposed on the outer side of the seal plate with the outer diameter end of the inner ring as the large diameter end. Alternatively, the outer ring surface end portion of the inner ring may be a small-diameter end, and the outer ring may be inclined outward to apply an outward axial component force to the elastic ring disposed on the inner side of the seal plate. Good.

  In the pulley bearing with the taper surface inclined inward, an inclined cylindrical portion inclined inward in the axial direction on the inner peripheral portion of the outer surface of the seal plate, and radially inward from the end of the inclined cylindrical portion. It is preferable that an elastic ring is elastically contacted with the inner peripheral portion of the outer surface of the small-diameter disk portion by providing a small-diameter disk portion that faces.

  If it carries out as mentioned above, an elastic ring will be stored in a crevice formed inside an inclined cylinder part, and a seal plate and an elastic ring will be arranged in parallel, and the axial direction length of an inner ring will be made compact. be able to. Further, the elastic ring is protected by the concave portion, and the contact with the foreign matter can be suppressed, and the elastic ring can be prevented from being damaged.

  On the other hand, in the pulley bearing with the tapered surface inclined outward, the elastic ring is disposed on the inner side of the seal plate, so the elastic ring is protected by the seal plate and is effective in preventing damage to the elastic ring. Can do. In addition, leakage of the grease sealed in the bearing to the outside can be effectively prevented.

  Since the elastic ring rotates in contact with the seal plate and the tapered surface, the elastic ring is preferably formed of rubber having excellent wear resistance. Examples of such rubber include nitrile rubber, acrylic rubber, and fluoro rubber.

  In the present invention, as described above, an elastic ring is attached to the inner peripheral portion of one surface of the seal plate whose outer peripheral portion is supported by the outer ring, and a tapered surface that is tightened by the elastic ring is provided on the outer diameter surface of the inner ring. Since the elastic ring is applied with an axial component force toward the seal plate, the elastic ring can be brought into elastic contact with both the inner peripheral surface of the seal plate and the tapered surface. However, good sealing performance can be ensured, and entry of foreign matter such as high-pressure washing water can be reliably prevented.

  In addition, if the elastic ring wears due to contact with the seal plate, the elastic ring moves to the small diameter end side along the taper surface, and maintains a contact state with the seal plate and the taper surface. Can be maintained over a long period of time.

The longitudinal cross-sectional view of the pulley unit formed with the pulley bearing which concerns on this invention The longitudinal cross-sectional view which shows embodiment of the bearing for pulleys concerning this invention (I) is an enlarged cross-sectional view showing the assembly part of the seal member of FIG. 2, (II) is an enlarged cross-sectional view showing a part of (I) Sectional drawing which shows other embodiment of the pulley bearing which concerns on this invention

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the pulley unit includes a pulley 10, a pair of bearings 20 that rotatably support the pulley 10, and a pulley shaft 40 that supports the bearing 20.

  The pulley 10 has a belt guide wheel 11 at an outer diameter portion, a resin molded product in which an annular flange 12 is formed on an inner diameter surface of the belt guide wheel 11, and a boss portion 13 is provided on the inner diameter portion of the annular flange 12. An inward flange 14 is provided at one end of the boss 13.

  The belt guide wheel 11 may be made of a metal processed product. Further, inward flanges may be provided at both ends of the boss portion 13.

  Here, the belt guide wheel 11 is for a flat belt guide whose outer diameter surface is a cylindrical surface 15, but is for a V belt guide having a plurality of V grooves formed on the outer diameter surface. Also good.

  As shown in FIG. 2, each of the pair of bearings 20 includes an outer ring 21, an inner ring 22, a rolling element 23 incorporated between the two rings 21 and 22, and a cage 24 that holds the rolling element 23. Both end openings of the bearing space 25 formed of ball bearings and formed between the opposed portions of the outer ring 21 and the inner ring 22 are sealed by incorporating a seal member 30.

  As shown in FIG. 1, the pair of bearings 20 is press-fitted into the inner diameter surface of the boss portion 13 in the pulley 10 to be arranged in tandem, and is formed by the inward flange 14 provided at one end portion of the boss portion 13. Positioned in the axial direction.

  The pulley shaft 40 has a cylindrical shape, and a flange 41 is provided at one end thereof. The pulley shaft 40 is press-fitted into the inner diameter surface of the inner ring 22 of the bearing 20 and integrated with the bearing 20, and is fixed by tightening a bolt 42 that is inserted into the pulley 20 and screwed into a pulley attachment target A such as an engine block.

  As shown in FIG. 3, the seal member 30 includes a seal plate 31 and an elastic ring 38 that is attached to the inner peripheral portion of the outer surface of the seal plate 31.

  The seal plate 31 is provided with an inward cylindrical portion 33 on the outer peripheral portion of the annular plate portion 32, and an outwardly facing disc portion 34 is continuously provided at an end portion of the cylindrical portion 33, so that the inner periphery of the annular plate portion 32 is provided. An inclined cylindrical portion 35 facing in the same direction as the cylindrical portion 33 is continuously provided in the portion, and is made of a press-formed product of a steel plate in which an inward small diameter disc portion 36 is provided at an end of the inclined cylindrical portion 35.

  A covering portion 37 made of rubber is provided on the outer peripheral portion of the seal plate 31 so as to cover the outward circular plate portion 34 and the inward cylindrical portion 33, and the covering portions 37 are formed at both ends of the inner surface of the outer ring 21. The outer periphery of the seal plate 31 is supported by the outer ring 21 by being press-fitted into the seal mounting groove 26.

  The elastic ring 38 is an O-ring having a circular cross section. The elastic ring 38 is mounted on the tapered surfaces 27 formed at both ends of the outer diameter surface of the inner ring 22 in an expanded state. The elastic ring 38 is elastically brought into contact with the tapered surface 27 by tightening by its own restoring elasticity. The part is sealed.

Here, the tapered surface 27 is inwardly inclined with both end portions of the inner ring outer diameter surface being large diameter ends, and the elastic ring 38 is tightened by the elastic ring 38, whereby the elastic ring 38 is indicated by an arrow in FIG. An axial component force f is applied, and the elastic ring 38 is elastically brought into contact with the outer surface of the small-diameter disk portion 36 of the seal plate 31 by the axial component force f to seal the contact portion. Here, F _O shown in FIG. 3 indicates a clamping force with which the elastic ring 38 clamps the tapered surface 27, and F ₁ indicates a component force in the direction along the tapered surface 27 of the clamping force F _O. Axial component force of the component force F ₁ along the tapered surface 27 is f.

  As described above, by setting the elastic ring 38 on the tapered surface 27 formed on the outer diameter surface of the inner ring 22 in an expanded state, the elastic ring 38 tightens the tapered surface 27 with its own reduced diameter restoring elasticity. Thus, the contact portion with the tapered surface 27 is sealed by the elastic contact. Further, in order to make elastic contact with the small-diameter disk portion 36 of the seal plate 31 by the applied axial component force f and seal the contact portion, the radial direction and the axial direction can be achieved with a simple configuration using a single elastic ring 38. The sealing performance in two directions is maintained, and foreign matter such as high-pressure washing water can be effectively prevented from entering the bearing.

  Here, when the outer ring 21 is rotated by the rotation of the pulley 10, the seal plate 31 is rotated together with the outer ring 21, and the seal plate 31 is rotated in contact with the elastic ring 38. When the elastic ring 38 is worn by the contact rotation, the elastic ring 38 moves along the tapered surface 27 toward the small diameter end side. For this reason, the contact state with respect to the seal plate 31 and the tapered surface 27 is always maintained, and good sealing performance is maintained over a long period of time.

  As described above, since the elastic ring 38 is worn by contact with the seal plate 31, it is preferably formed of rubber having excellent wear resistance. Examples of such rubber include nitrile rubber, acrylic rubber, and fluorine rubber.

  As shown in FIG. 3, an inwardly inclined cylindrical portion 35 is provided on the inner peripheral portion of the seal plate 31, and on the outer surface of the inwardly small-diameter disc portion 36 connected to the end of the inclined cylindrical portion 35. When the elastic ring 38 is brought into elastic contact, the elastic ring 38 is accommodated in a recess 39 formed inside the inclined cylindrical portion 35, and the seal plate 31 and the elastic ring 38 are arranged in parallel. The axial length of the inner ring 22 can be made compact.

  Further, since the elastic ring 38 is protected by the recess 39, it is possible to prevent damage due to contact with foreign matter.

  FIG. 4 shows another embodiment of the pulley bearing according to the present invention. In this embodiment, an outwardly inclined taper surface 28 having an outer diameter surface end portion as a small diameter end is provided at both ends of the outer diameter surface of the inner ring 22, and the taper surface 28 is tightened by being mounted on the taper surface 28. 3 is different from the pulley bearing shown in FIG. 3 in that the elastic ring 38 is elastically brought into contact with the inner peripheral portion of the inner side surface of the annular plate portion 32 of the seal plate 31. For this reason, the same code | symbol is attached | subjected to the part same as the pulley bearing shown in FIG. 3, and description is abbreviate | omitted.

  In the embodiment shown in FIG. 4, the elastic ring 38 tightens the tapered surface 28 with its own reduced diameter restoring elasticity and seals the contact portion with the tapered surface 28 by elastic contact. Further, an axial component force f directed outward in the axial direction is applied to the elastic ring 38 by the contact with the tapered surface 28, and the axial component force f is applied to the inner peripheral surface of the inner surface of the annular plate portion 32 of the seal plate 31. Elastic contact is made to seal the contact.

  For this reason, similarly to the case shown in FIG. 3, the sealability in the radial direction and the axial direction can be maintained with a simple configuration by the single elastic ring 38, and high-pressure washing water or the like inside the bearing can be maintained. Intrusion of foreign matter can be effectively prevented.

  In addition, since the elastic ring 38 is protected by the seal plate 31 by providing the elastic ring 38 on the inner side of the seal plate 31, it can be effective in preventing damage to the elastic ring 38 and is enclosed in the bearing. Leakage of grease to the outside can be effectively prevented.

  In FIG. 2, a single row ball bearing is shown, and the pulley 10 shown in FIG. 1 is rotatably supported by two single row ball bearings. However, the bearing is not limited to a single row ball bearing, For example, a double row ball bearing may be used.

21 Outer ring 22 Inner ring 25 Bearing space 26 Seal mounting groove 27 Tapered surface 28 Tapered surface 30 Seal member 31 Seal plate 35 Inclined cylindrical portion 36 Small diameter disc portion 38 Elastic ring

Claims (5)

A rolling element (23) is assembled between the outer ring (21) and the inner ring (22), and both opening portions of the bearing space (25) formed between the opposed parts of the outer ring (21) and the inner ring (22) are sealed. In the pulley bearing sealed by incorporating the member (30),
The seal member (30) has an annular elastic seal plate (31) whose outer periphery is supported by seal mounting grooves (26) formed at both ends of the inner surface of the outer ring (21), and the seal plate A tapered surface (31) comprising an elastic ring (38) having a circular cross section attached to the inner peripheral portion of one side of (31), and being clamped by the elastic ring (38) at both ends of the outer diameter surface of the inner ring (22). 27, 28), and the elastic ring (38) is attached to the inner surface of one side of the seal plate (31) by an axial component force applied to the elastic ring (38) by tightening the tapered surfaces (27, 28). Pulley bearing characterized by elastic contact with the part.   The tapered surface (27) has an inward slope that applies an inward axial component to the elastic ring (38) with the outer diameter end of the inner ring (22) as the large diameter end, and the elastic ring The pulley bearing according to claim 1, wherein (38) is brought into elastic contact with an inner peripheral portion of an outer side surface in the axial direction of the seal plate (31).   The seal plate (31) has an inclined cylindrical portion (35) inclined inward in the axial direction on the inner peripheral portion, and a small-diameter disk portion (36 that faces radially inward from the end of the inclined cylindrical portion (35). The pulley bearing according to claim 2, wherein the elastic ring (38) is brought into elastic contact with an inner peripheral portion of an outer surface of the small-diameter disk portion (36).   The tapered surface (28) has an outward slope that applies an outward axial component force to the elastic ring (38) with the outer diameter surface end of the inner ring (22) as a small diameter end, and the elastic ring ( The pulley bearing according to claim 1, wherein 38) is elastically contacted with an inner peripheral portion of an inner side surface in the axial direction of the seal plate (31).   The pulley bearing according to any one of claims 1 to 4, wherein the elastic ring (38) is made of one of nitrile rubber, acrylic rubber, and fluororubber.

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