JP6030414B2 - Pulley arm fulcrum bearing device - Google Patents

Description

  The present invention relates to a fulcrum bearing device for a pulley arm that supports a tension pulley for belt tension adjustment.

  In general, in belt transmissions that drive engine accessories such as compressors and water pumps for alternators and air conditioners, a hydraulic auto tensioner is connected to a swingable pulley arm that supports a tension pulley. The adjustment force applied to the pulley arm from the tensioner urges the pulley arm in the direction in which the tension pulley presses the belt, and the belt tension change is absorbed by the hydraulic auto tensioner to keep the belt tension constant. .

  Since the belt transmission as described above is provided outside the engine, there is a possibility that foreign matters such as muddy water and dust may enter the fulcrum bearing portion serving as the swing center of the pulley arm. Since the entry of the foreign matter impedes the swinging of the pulley arm, or the life of the bearing portion is significantly reduced, it is necessary to take measures to prevent the foreign matter from entering the fulcrum bearing portion.

  Conventionally, a pulley arm fulcrum bearing device in which measures for preventing intrusion of foreign matter are taken is described in Patent Document 1.

  In the fulcrum bearing device for a pulley arm described in Patent Document 1, a sleeve serving as a fulcrum shaft is inserted into the central hole of a cylindrical boss provided in the pulley arm, and the sleeve and the inner surface of the central hole are inserted between the sleeves. A slide bearing that rotatably supports the sleeve and pulley arm is incorporated, a washer is fitted to each of the small-diameter cylindrical portions formed at both ends of the sleeve, and the bolt inserted inside the sleeve is connected to the engine block. The sleeve and the washer are fixed by tightening the bolt and the pulley arm is swingably supported around the sleeve.

  Further, as shown in FIG. 5 (a), an annular recess 22 having a larger diameter than the center hole 21 is provided at both ends of the center hole 21 in the boss portion 20, and a seal member 23 is incorporated in the recess 22. An annular base portion 23a provided on the seal member 23 is fitted to the end portion of the sleeve 24, and one of the seal lips 23b and 23c of the seal lips 23b and 23c connected to the base portion 23a is inclined in opposite directions. The boss portion in which the slide bearing 26 and the sleeve 24 are incorporated by the seal member 23 is elastically brought into contact with the side surface of the recess 22 and the tip portion of the other seal lip 23c is brought into elastic contact with the inner surface of the washer 25. This prevents foreign matter such as muddy water and dust from entering the center hole 21 of the 20.

US Patent No. 790140

  By the way, in the fulcrum bearing device described in Patent Document 1, when the pulley arm swings at high speed due to vibration propagation from the belt, heat is generated by contact friction at the slide bearing 26, and the fulcrum bearing becomes the center of the swing. The inside is likely to become hot. As the internal pressure increases due to the temperature change in the fulcrum bearing, as shown in FIG. 5 (b), one seal lip 23b is elastically deformed outward and is kept away from the side surface of the recess 22 to maintain adhesion. It is impossible to prevent foreign matter from entering from the outside.

  An object of the present invention is to provide a fulcrum bearing device for a pulley arm that can ensure a good sealing performance even when the pressure rises due to a temperature change inside the fulcrum bearing.

  In order to solve the above-described problems, in the present invention, a cylindrical boss that supports a tension pulley and that is pivoted by a pulley arm that is urged by a hydraulic auto tensioner in a direction in which the tension pulley presses the belt. A sleeve is inserted into the central hole of the boss portion, and washers are fitted to both end portions of the sleeve that are located outward from the both end surfaces of the boss portion, and each of the washer and the sleeve is inserted into the sleeve. The pulley arm is fixed to an arm attachment target by tightening a bolt inserted into the pulley, and the pulley arm is supported in a swingable manner. At both ends of the center hole of the boss portion, seal receiving recesses having a diameter larger than the center hole are provided. A pulley arm fulcrum bearing device that incorporates a seal member into the seal housing recess to prevent foreign material from entering the boss from the outside. The sealing member is made of an elastic material, and a cylindrical portion press-fitted into the inner diameter surface of the seal housing recess, an inwardly-shaped annular portion connected to the outer end of the cylindrical portion, and the annular portion A taper-shaped radial lip that inclines obliquely inwardly from the inner periphery of the cylindrical portion, and the tip of the radial lip is in elastic contact with the outer diameter surface of the sleeve. Adopted.

  As described above, the annular member is connected to the outer end of the cylindrical portion that is press-fitted into the inner diameter surface of the seal accommodating recess, and the cylinder is provided from the inner periphery of the annular portion. A boss that serves as the center of oscillation of the pulley arm is formed by providing a tapered radial lip that inclines inwardly toward the inside and elastically contacts the distal end of the radial lip with the outer diameter surface of the sleeve. When the pressure rises due to the temperature rise in the part, the radial lip is elastically deformed in the direction of reducing the diameter, and the tip part comes into contact with the outer diameter surface of the sleeve more strongly. Will be secured.

  Here, an axial lip that is inclined obliquely outward is provided on the inner peripheral portion of the outer surface of the annular portion of the seal member, and the tip of the axial lip is elastically contacted with the inner surface of the washer. If the pressure in the boss part drops due to a temperature drop and the internal pressure becomes lower than the external pressure, the radial lip elastically deforms outward in the radial direction and the contact pressure decreases. The axial lip is elastically deformed toward the washer by the pressure and comes into strong contact with the inner side surface of the washer, and even when the pressure inside the bearing is lowered from the outside, good sealing performance can be ensured.

  An L-shaped seal core having an inward flange whose outer surface is covered with an annular portion of the sealing member at one end of the cylindrical portion whose outer diameter surface and end surface are covered with the cylindrical portion of the sealing member When gold is provided on the seal member, the seal member can be reinforced with the seal core, so that the assemblability of the seal member can be improved and a stable assembled state can be obtained.

  In the pulley arm fulcrum bearing device according to the present invention, an annular concave step portion is formed on the outer peripheral portion of the inner surface facing the end surface of the boss portion of the washer, and is fitted into the seal housing concave portion inside the concave step portion. And the movement of the pulley arm in the axial direction is restricted by the side surface of the concave step portion facing the end surface of the boss portion with a minute gap, and the axial lip is provided on the side surface of the circular bulge portion. Since the side surface of the circular bulging portion with which the axial lip elastically contacts enters the boss portion from the end surface of the boss portion and a distance is ensured between the minute gaps, A foreign matter adheres to the side surface and the sealing performance is hardly hindered, and a good sealing performance can be maintained over a long period of time.

  Here, the tip outer diameter in the natural state of the axial lip is smaller than the inner diameter of the cylindrical portion of the seal metal core, and the tip outer diameter of the axial lip in the state of elastic contact with the side surface of the circular bulge is circular. When the diameter is smaller than the outer diameter of the bulging portion, it is possible to prevent the tip portion of the axial lip from being sandwiched between the opposed surfaces of the washer and the boss portion when the fulcrum bearing device is assembled.

  In addition, if a tapered surface that forms a gap between the outer peripheral edge of the side surface of the circular bulge portion is provided at the inner peripheral portion at the opening end of the seal housing recess, the boss portion is swung around due to the formation of the play in the rotational direction. Even if it moves in the axial direction within the range of the minute gap formed with the washer, the outer periphery of the circular bulge does not come into contact with the inner diameter surface of the seal housing recess, and the swing of the pulley arm is hindered. Can be prevented.

  The sealing member that seals the open end of the boss part is a synthetic rubber with excellent wear resistance because the radial lip is in frictional contact with the outer diameter surface of the sleeve and the axial lip is in frictional contact with the inner surface of the washer. It is good to form with. Examples of such rubber include nitrile rubber, hydrogenated nitrile rubber, ACM rubber, silicon rubber, and fluorine rubber.

  In the present invention, as described above, the seal member incorporated in the seal housing recess of the boss portion includes the cylindrical portion, the inwardly-circular ring portion continuously provided on the outer end of the cylindrical portion, and the circular ring. A tapered radial lip that is inclined obliquely inward from the inner periphery of the cylindrical portion, and the cylindrical portion is press-fitted into the inner diameter surface of the seal receiving recess, and the tip of the radial lip is connected to the sleeve Since the outer diameter surface is elastically contacted, when the pressure rises due to the temperature rise in the boss portion, the radial lip is elastically deformed in the direction to reduce the diameter, so that the tip of the radial lip contacts the outer diameter surface of the sleeve. The force is increased, a good sealing property can be secured at the contact portion of the radial lip, and entry of foreign matters can be stably prevented.

Front view of a belt drive device for driving an auxiliary machine employing a fulcrum bearing device for a pulley arm according to the present invention Sectional view along the line II-II in FIG. 2 is an enlarged cross-sectional view of the fulcrum bearing portion of FIG. FIG. 3 is an enlarged cross-sectional view of the assembly portion of the seal member (a) is sectional drawing which shows a part of conventional fulcrum bearing part, (b) is sectional drawing which shows the state which the sealing member elastically deformed by the raise of internal pressure

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a belt drive device for driving auxiliary equipment. In this belt transmission device, a pulley arm 1 that is swingably supported, a tension pulley 2 that is rotatably supported at the swing side end of the pulley arm 1, and a direction in which the tension pulley 2 presses the belt B. And a hydraulic auto tensioner 3 for urging the pulley arm 1.

  As shown in FIG. 2, the pulley arm 1 has a cylindrical boss portion 4. A slide bearing 6 is incorporated in the center hole 5 of the boss portion 4, and a metal sleeve 7 is fitted in the slide bearing 6. Are combined.

  The sleeve 7 is longer than the axial length of the boss portion 4, and is provided with small-diameter cylindrical portions 7 a at both ends facing the outside from both ends of the boss portion 4, and a washer 8 is fitted to each outer periphery of the small-diameter cylindrical portion 7 a. ing. The washer 8 is made of metal and plated to give corrosion resistance.

  The sleeve 7 and the washer 8 are fixed to the engine block 10 by tightening a bolt 9 inserted into the sleeve 7 and screwed into the engine block 10 as an arm attachment target, and the pulley arm 1 is configured with the sleeve 7 and the washer 8 as a fulcrum shaft. It can be swung.

  As shown in FIG. 3, seal accommodating recesses 11 having a diameter larger than that of the central hole 5 are formed at both ends of the central hole 5 of the boss portion 4, and a seal member 12 is incorporated in each of the seal accommodating recesses 11. It is.

  As shown in FIG. 4, the seal member 12 has an inwardly-circular ring portion 12b continuously provided on the outer end of a cylindrical portion 12a that is press-fitted into the inner diameter surface of the seal housing recess 11, and the inner periphery of the ring portion 12b. It is made of a synthetic rubber molded product provided with a radial lip 12c at the part and provided with an axial lip 12d on the inner peripheral part of the outer surface of the annular part 12b. As synthetic rubber, rubber having excellent wear resistance is used. Examples of such rubber include nitrile rubber, hydrogenated nitrile rubber, ACM rubber, silicon rubber, and fluorine rubber.

  The seal core 12 is molded when the seal member 12 is molded. The seal core 13 has an L-shaped cross section in which an inward flange 13b is provided at one end of the cylindrical portion 13a, the outer diameter surface and the end surface of the cylindrical portion 13a are covered with the cylindrical portion 12a of the seal member 12, and The outer surface of the inward flange 13b is molded so as to be covered with the annular portion 12b, and the seal member 12 is reinforced.

  The radial lip 12 c in the seal member 12 is tapered such that the inside of the cylindrical portion 12 a is inclined obliquely inward, and the tip thereof is in elastic contact with the outer diameter surface of the sleeve 7. Further, the axial lip 12d is tapered so as to be inclined obliquely outward, and its tip is in elastic contact with the inner surface of the washer 8.

  An annular concave step portion 8a is formed on the outer peripheral portion of the inner surface facing the end face of the boss portion 4 of the washer 8, and a circular bulging portion 8b is provided on the inner surface of the washer 8 by the formation of the concave step portion 8a. Yes. The circular bulging portion 8b is fitted in the seal housing recess 11, and the tip of the axial lip 12d of the seal member 12 is in elastic contact with the inner surface of the bulging portion 8b.

  Here, if the side surface of the recessed step portion 8a is in contact with the end surface of the boss portion 4, the swing of the pulley arm 1 is inhibited by the friction of the contact portion. A minute gap 14 is provided between the end faces of the portion 4. For this reason, the boss part 4 is movable in the axial direction within the range of the gap 14, and the movement of the boss part 4 in the axial direction is restricted by the side surface of the concave step part 8a.

  Further, in the case where the boss portion 4 moves in the axial direction within the range of the minute gap 14, if a backlash occurs in the rotational direction inside the boss portion 4, the boss portion 4 is swung around, and the circular bulge portion 8b. It is conceivable that the outer diameter surface of the boss contacts the inner diameter surface of the seal housing recess 11 and the movement of the boss portion 4 is obstructed. Therefore, in FIG. 4, a tapered surface 15 is provided at the opening end of the seal housing recess 11, and the boss 4 is moved in the axial direction between the outer peripheral edge E and the tapered surface 15 on the side surface of the circular bulge portion 8 b. A relatively large interval is formed.

  In FIG. 4, the chain line a in FIG. 4 indicates the natural state of the axial lip 12 d, and the distal end outer diameter D of the axial lip 12 d in the natural state is smaller than the inner diameter d of the cylindrical portion 13 a in the seal core 13. Further, the outer diameter of the tip end of the axial lip 12d in a state of elastic contact with the side surface of the circular bulge portion 8b is smaller than the outer diameter of the circular bulge portion 8b, and the tip end portion of the axial lip 12d is circular bulge. The state which always contacts the side surface of the protruding portion 8b is ensured.

  The pulley arm fulcrum bearing device shown in the embodiment has the above-described structure, and the seal member 12 is assembled in the seal housing recess 11 in the previous stage where the washer 8 is fitted to the small diameter cylindrical portion 7a of the sleeve 7. The cylindrical end 12a is pressed into the inner diameter surface of the seal fitting recess 11 with the opening end of the cylindrical portion 12a first, and the distal end of the radial lip 12c is brought into elastic contact with the outer diameter surface of the sleeve 7. .

  After the assembly of the sealing member 12 as described above, the washer 8 is fitted to each of the small-diameter cylindrical portions 7 a at both ends of the sleeve 7. In this case, the washer 8 is fitted with the circular bulging portion 8b first. Since the circular bulging portion 8b presses the axial lip 12d by the fitting of the washer 8, the axial lip 12d is elastically deformed, and its distal end elastically contacts the side surface of the circular bulging portion 8d by its restoring elasticity. .

  Here, the axial direction lip 12d is such that the tip outer diameter D in the natural state is smaller than the inner diameter d of the cylindrical portion 13a in the seal core 13 and is in elastic contact with the side surface of the circular bulging portion 8b. Since the outer diameter of the tip end of the axial lip 12d is smaller than the outer diameter of the circular bulge portion 8b, the tip end of the axial lip 12d is caught between the opposing portions of the boss portion 4 and the washer 8 when the washer 8 is assembled. There is no inconvenience. Further, it is possible to always ensure a state in which the tip end portion of the axial lip 12d is in elastic contact with the side surface of the circular bulge portion 8b.

  After assembling the sealing member 12 and the washer 8 as described above, when the bolt 9 is inserted into the sleeve 7 and the bolt 9 is screwed into the engine block 10 and tightened, the sleeve 7 and the washer 8 are fixed. The pulley arm 1 is swingably supported around the sleeve 7.

  As shown in FIGS. 1 and 2, when the tension of the belt B changes in the tension adjustment state of the belt B that supports the pulley arm 1 so as to be swingable and applies the adjustment force of the hydraulic auto tensioner 3 to the pulley arm 1. The pulley arm 1 swings around the sleeve 7. Due to the oscillation, heat is generated due to contact friction at the slide bearing 6 and the temperature rises, and the pressure in the boss portion 4 rises due to the temperature change.

  At this time, since the radial lip 12c provided in the seal member 12 is inclined obliquely inward, the radial lip 12c is elastically deformed in the direction of reducing the diameter by the pressure in the boss portion 4, and the front end. The portion is strongly pressed by the outer diameter surface of the sleeve 7. For this reason, a favorable sealing property is ensured at the tip contact portion of the radial lip 12c, and the entry of foreign matter from the outside is stably prevented.

  Here, when the engine is stopped, the temperature in the boss portion 4 is lowered and the pressure is lowered, and when the internal pressure becomes lower than the external pressure, the contact pressure of the radial lip 12c with respect to the outer diameter surface of the sleeve 7 is lowered. As a result, the sealing performance decreases. However, at this time, the axial lip 12d is elastically deformed toward the washer 8 by the external pressure, and comes into strong contact with the side surface of the circular bulging portion 8b. Therefore, even when the pressure in the boss portion 4 is reduced from the outside, a good sealing property is ensured, and entry of foreign matter is stably prevented.

DESCRIPTION OF SYMBOLS 1 Pulley arm 2 Tension pulley 3 Hydraulic type auto tensioner 4 Boss part 5 Center hole 7 Sleeve 8 Washer 8a Concave step part 8b Circular bulge part 9 Bolt 10 Engine block (arm attachment object)
DESCRIPTION OF SYMBOLS 11 Seal accommodation recessed part 12 Seal member 12a Cylindrical part 12b Annular part 12c Radial direction lip 12d Axial direction lip 13 Seal core metal 13a Cylindrical part 13b Inward flange 14 Micro gap 15 Tapered surface

Claims (5)

A cylindrical boss portion serving as a swing center is provided on a pulley arm that supports a tension pulley and is urged in a direction in which the tension pulley presses the belt by a hydraulic auto tensioner. Insert and insert washers into both ends of the sleeve that are located outside both end faces of the boss, and fix the washers and sleeves to the arm mounting target by tightening the bolts inserted into the sleeves. The pulley arm is swingably supported, and a seal accommodating recess having a diameter larger than that of the central hole is provided at both ends of the central hole of the boss portion. In the pulley arm fulcrum bearing device designed to prevent the entry of foreign matter into the part,
The seal member is made of an elastic material, and a cylindrical portion that is press-fitted into the inner diameter surface of the seal housing recess, an inward annular portion that is connected to an outer end of the cylindrical portion, and an inner portion of the annular portion A taper-shaped radial lip that inclines obliquely inwardly within the cylindrical portion from the periphery, and the tip portion of the radial lip is brought into elastic contact with the outer diameter surface of the sleeve ,
An axial lip that is inclined obliquely outward is provided on the inner peripheral portion of the outer surface of the annular portion of the seal member, and the tip end portion of the axial lip is brought into elastic contact with the inner surface of the washer .
An annular concave step portion is formed on the outer peripheral portion of the inner surface facing the end surface of the boss portion of the washer, and a circular bulging portion fitted into the seal housing concave portion is provided inside the concave step portion. The movement of the pulley arm in the axial direction is restricted by the side surface of the concave step portion facing the end surface of the boss portion with a minute gap, and the axial lip is brought into elastic contact with the side surface of the circular bulge portion. A fulcrum bearing device for a pulley arm. The seal member is reinforced by a seal core, the seal core is provided with an inward flange at one end of the cylindrical portion to have an L-shaped cross section, and an outer diameter surface and an end surface of the cylindrical portion are formed on the seal member. The fulcrum bearing device for a pulley arm according to claim 1, wherein the pulley arm is covered with a cylindrical portion, and an outer surface of the inward flange is covered with an annular portion of the seal member. The outer diameter of the tip end of the axial lip in the natural state is smaller than the inner diameter of the cylindrical portion of the seal metal core, and the tip outer diameter of the axial lip in a state of elastic contact with the side surface of the circular bulge portion is circular. The fulcrum bearing device for a pulley arm according to claim 2, wherein the outer diameter of the bulging portion is smaller. The fulcrum bearing of the pulley arm of any one of Claims 1 thru | or 3 which provided the taper surface which forms a space | gap between the outer peripheral edge of the said circular bulging part in the inner peripheral part in the opening end of the said seal accommodation recessed part. apparatus. The fulcrum bearing device for a pulley arm according to any one of claims 1 to 4, wherein the seal member is made of synthetic rubber of any one of nitrile rubber, hydrogenated nitrile rubber, ACM rubber, silicon rubber, and fluorine rubber.

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