Strut bearing, and strut type suspension of vehicle

Abstract

To provide a strut bearing in which water or dust having intruded from the outside of the strut bearing is difficult to reach the inside of a bearing through an outer diameter side seal.SOLUTION: An outer diameter side seal 9 has a contact type seal lip 11 close to a rolling element, and a non-contact type water-resistant suppression body 12 of the seal lip 11 far from the rolling element. A tip part A of the seal lip 11 expands in diameter as it moves upward. An upper part of a surface B on a radially outward RO of the water-resistant suppression body 12 is a wall surface C that expands in diameter as it moves upward. A lower surface 2A of an upper case 2 has a first annular lower surface P1, a second annular lower surface P2 that is stepped down from the first lower surface P1 and positioned radially outward RO with respect to the first lower surface P1, and an inner surface Q that connects the first lower surface P1 and the second lower surface P2. The seal lip 11 contacts the first lower surface P1, and the water-resistant suppression body 12 faces the inner surface Q.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a strut bearing used in a strut type suspension of a vehicle.

Background Art

[0002] As a suspension that supports a wheel with respect to a vehicle body by a coil spring and includes a shock absorber to absorb vertical vibrations, there is a strut type suspension in which a telescopic column (strut) incorporating a shock absorber is fixed to an axle. The strut type suspension is mainly widely used for the front wheels of passenger cars.

[0003] As a strut bearing used at the upper part of the strut type suspension, there is one in which two seal lips are provided on an outer diameter side seal located radially outward of rolling elements (for example, refer to the outer seal 19 having seal lips 19b and 19c in Patent Document 1).

[0004] The outer seal 19 of Patent Document 1 has a base portion 19a fixed to the lower cap 16, and a first seal lip 19b and a second seal lip 19c extending from the base portion 19a toward the upper cap 14. The seal lips 19b and 19c are non-contact type or contact type, and a lubricant 42 is accommodated in an annular chamber 40 between the seal lips 19b and 19c.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The strut bearing is used in a harsh muddy water environment where it directly receives muddy water or the like on the road surface where the wheel has bounced up. Moreover, when a high-pressure washer is used during car washing, the strut bearing will receive the high-pressure water discharged from the high-pressure washer during the washing of the undercarriage.

[0007] The tip of the first seal lip 19b close to the rolling element 24 in the outer seal 19 of Patent Document 1 is inclined so as to face the rolling element 24, and a substance radially outward of the first seal lip 19b is easily pushed radially inward of the first seal lip 19b.

[0008] In the outer seal 19 of Patent Document 1, water and dust that have entered from the second seal lip 19c located at a position far from the rolling element 24 may mix with the lubricant 42 in the chamber 40, and the mixed contaminants may enter the inside of the bearing 18 beyond the first seal lip 19b close to the rolling element 24.

[0009] When the seal lips 19b and 19c are non-contact type, a gap is formed between the upper cap 14 after the lubricant 42 leaks, thereby creating a passage for water and dust, so there is a risk that water and dust may enter the inside of the bearing 18.

[0010] An object of the present invention is to provide a strut bearing in which water and dust that have entered from the outside of the strut bearing are less likely to reach the inside of the bearing through the outer diameter side seal.

Means for Solving the Problems

[0011] The strut bearing according to the present invention is a strut bearing used for a strut type suspension of a vehicle, comprising an upper case and a lower case, an upper race ring held by the upper case, a lower race ring held by the lower case, rolling elements that roll between the upper race ring and the lower race ring, and an outer diameter side seal located radially outside the rolling elements. The outer diameter side seal has a contact type seal lip close to the rolling elements and a water repellent body of the seal lip, which is a non-contact type and far from the rolling elements. When the rotation axis of the strut bearing is in the vertical direction, the tip of the seal lip expands in diameter as it goes upward, and the upper part of the radially outer surface of the water repellent body is a wall surface that expands in diameter as it goes upward. The lower surface of the upper case has an annular first lower surface, an annular second lower surface that descends from the first lower surface and is located radially outside the first lower surface, and an inner peripheral surface that connects the first lower surface and the second lower surface. The seal lip contacts the first lower surface, and the water repellent body faces the inner peripheral surface.

[0012] The strut type suspension of a vehicle according to the present invention includes the strut bearing.

Advantages of the Invention

[0013] According to the strut bearing and the strut type suspension of a vehicle according to the present invention as described above, the upper part of the radially outer surface of the water repellent body of the seal lip, which is hit by muddy water or the like that has entered from the axial gap radially outside the strut bearing, is a wall surface that expands in diameter as it goes upward. Therefore, the effect of attenuating the water potential of muddy water or the like hitting the water repellent body is increased, and it is difficult for the muddy water or the like to cross over the water repellent body.

[0014] The water repellent body is of a non-contact type, and there is always a gap between it and the inner peripheral surface of the upper case. Therefore, muddy water or the like that has entered between the seal lip and the water repellent body can be discharged from the gap. Since the water repellent body is of a non-contact type, a lubricant is not applied to the tip of the water repellent body, so water, dust, and the lubricant do not mix.

[0015] The seal lip is of the contact type and expands in diameter as it goes upward. Therefore, substances located radially outward of the seal lip are less likely to be pushed radially inward of the seal lip and less likely to penetrate into the inside of the bearing beyond the seal lip.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments according to the present invention will be described based on the drawings.

[0018] In this specification, the direction parallel to the rotation axis O (see Fig. 1) of the strut bearing 1 is the "axial direction" (for example, see the arrow J in Fig. 1), the direction perpendicular to the rotation axis O is the "radial direction" (for example, see the arrow R in Fig. 1), the radial direction approaching the rotation axis O is the "inward radial direction" (for example, see the arrow RI in Fig. 1), and the radial direction away from the rotation axis O is the "outward radial direction" (for example, see the arrow RO in Fig. 1).

[0019] <Strut type suspension> The strut type suspension S of the vehicle shown in Fig. 1 is used with a telescopic strut 13 incorporating a shock absorber fixed to an axle (not shown) and an upper mount 19 fixed to the vehicle body. In the example of the strut type suspension S of the vehicle shown in Fig. 1, the rotation axis O of the strut bearing 1 is in the vertical direction, and thus the axial direction J is also in the vertical direction.

[0020] At the upper part of the strut type suspension S, there is provided a strut bearing 1 that swings and rotates by an amount corresponding to the change in the direction of the steering wheel during steering operation while supporting the vehicle body. The swing angle of the strut bearing 1 is determined corresponding to the allowable steering angle of the wheel, and is set, for example, in the range of 40° or more and 50° or less.

[0021] On the outward radial direction RO of the strut 13, there are provided a coil spring 14 which is a suspension spring, and a dust boot 15 for protecting the oil seal of the shock absorber from foreign matters such as sand. The strut type suspension S includes a spring support component 16 that supports the upper end of the coil spring 14. The spring support component 16 is composed of an upper spring seat 17 and an upper insulator 18.

[0022] <Strut bearing> As shown in Figs. 1 and 2, the strut bearing 1 according to the embodiment of the present invention includes an upper case 2 and a lower case 3, an upper race ring 4 and a lower race ring 5, rolling elements 6, a retainer 7, an inner diameter side seal 8, an outer diameter side seal 9, and the like.

[0023] The lower surface 2A of the upper case 2 has an annular first lower surface P1, an annular second lower surface P2 that is offset from the first lower surface P1 and is located radially outward RO from the first lower surface P1, and an inner peripheral surface Q that connects the first lower surface P1 and the second lower surface P2. The lower surface 2A of the upper case 2 may be an uneven surface or the like. For example, when the lower surface 2A is made into a curved surface in consideration of the contact relationship with the tip of the seal lip 11 (Fig. 3) of the outer diameter side seal 9, or when the lower surface 2A is made into an uneven surface (pear texture, dimples, etc.) to improve the retention of the lubricant.

[0024] The upper case 2 is fixed to the upper end of the strut 13, and the lower case 3 receives the upper spring seat 17 from above. The upper raceway ring 4 is held by the upper case 2, and the lower raceway ring 5 is held by the lower case 3. The rolling elements 6 roll between the upper raceway ring 4 and the lower raceway ring 5, and the cage 7 holds the adjacent rolling elements 6 so that they do not contact each other.

[0025] The inner diameter side seal 8 is located radially inward RI of the rolling element 6, and the outer diameter side seal 9 is located radially outward RO of the rolling element 6.

[0026] The upper raceway ring 4 and the lower raceway ring 5 are made of steel, formed by pressing from a steel plate, and hardened by quenching after processing. The upper case 2 and the lower case 3 are made of synthetic resin, and the inner diameter side seal 8 and the outer diameter side seal 9 are made of elastomer. The water-repellent body 12 of the seal lip 11 of the outer diameter side seal 9 shown in Fig. 3 is made of elastomer, but as shown in Fig. 6, the water-repellent body 12 may be made of synthetic resin and integrally formed with the lower case 3.

[0027] The synthetic resin used for the upper case 2 and the lower case 3 is, for example, polyamide-based (PA66, PA46, PA612, PA6, PA9T, PA10T, etc.), and contains, for example, 20 to 60% by weight of glass fiber (GF) as a reinforcing fiber.

[0028] The elastomers used for the inner diameter side seal 8 and the outer diameter side seal 9 are thermoplastic elastomers (TPE) such as TPS (styrene-based), TPO (olefin-based), TPU (urethane-based), TPA (amide-based), TPEE (ester-based), etc., and rubber materials such as nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), ethylene-acrylic rubber (AEM), fluororubber (FKM, FPM), silicone rubber (VQM), etc. The rubber material can be used by appropriately blending one kind or two or more kinds of rubbers.

[0029] <Outer diameter side seal> As shown in FIGS. 2 and 3, the outer diameter side seal 9 includes a base 10, a seal lip 11 close to the rolling element 6, and a water-repellent body 12 of the seal lip 11 far from the rolling element 6. The base 10 is attached to the lower case 3. The seal lip 11 is a contact type and contacts the first lower surface P1 of the lower surface 2A of the upper case. The water-repellent body 12 is a non-contact type, faces the inner peripheral surface Q of the upper case 2, and there is a gap G between it and the inner peripheral surface Q. A lubricant is applied to the contact-type seal lip 11, and no lubricant is applied to the non-contact-type water-repellent body 12.

[0030] The tip A of the seal lip 11 expands in diameter as it goes upward. The upper part of the surface B in the radially outer direction RO of the water-repellent body 12 is a wall surface C that expands in diameter as it goes upward. The longitudinal section of the wall surface C may be a straight line or a curve.

[0031] There is a height difference H between the tip E1 (the first lower surface P1) of the seal lip 11 and the tip E2 of the water-repellent body 12, and a preferred embodiment is that H≧0.5 mm. This is to enhance the effect of making the tip of the seal lip 11 less likely to be wetted by water.

[0032] In FIG. 3, the gap G between the tip E3 of the water-repellent body 12 and the inner peripheral surface Q is set to 0.3 mm≦G≦F. This is to maintain the function of the water-repellent body 12 by preventing the seal lip 11 from being directly wetted by water and preventing it from contacting the inner peripheral surface Q.

[0033] <Modification Example> When injection molding the upper case 2, the lower case 3, and the outer diameter side seal 9, considering the fluidity of the material, the strength of the parts after molding, the interference with the mating parts, etc., as shown in FIG. 4, the inner peripheral surface Q of the upper case 2 and the base 10 of the outer diameter side seal 9 may be inclined.

[0034] A substantially V-shaped groove as shown in FIGS. 3 and 4 may not be provided between the seal lip 11 and the water-repellent body 12, and the water-repellent body 12 may be shaped as shown in FIG. 5, for example. The upper surface of the water-repellent body 12 shown in FIG. 5 is inclined downward as it goes radially outward RO. Thereby, muddy water and the like that have entered between the seal lip 11 and the water-repellent body 12 are easily discharged.

[0035] Since the water-repellent body 12 is a non-contact type, as shown in FIG. 6, it may be integrally molded with the lower case 3 made of synthetic resin instead of an elastomer.

[0036] The upper wall surface C of the surface B in the radially outer RO of the water-repellent body 12 may be a curved surface that expands in diameter as it goes upward, as shown in FIG. 7, or may be overhung so as to protrude radially outward RO, as shown in FIG. 8. Even in these cases, similarly, an effect of attenuating the water potential of muddy water and the like hitting the surface B in the radially outer RO of the water-repellent body 12 can be expected.

[0037] <Function and Effect> According to the strut bearing 1 according to the embodiment of the present invention as described above, and the strut type suspension S of the vehicle, the upper part of the surface B in the radially outer RO of the water-repellent body 12 of the seal lip 11 against which muddy water and the like that have entered from the axial gap D in the radially outer RO of the strut bearing 1 hits is a wall surface C that expands in diameter as it goes upward. Therefore, the effect of attenuating the water potential of muddy water and the like hitting the water-repellent body 12 is increased, and it is difficult for the muddy water and the like to overcome the water-repellent body 12.

[0038] The water suppression body 12 is non-contact type, and there is always a gap G between it and the inner peripheral surface Q of the upper case 2. Therefore, muddy water or the like that has entered between the seal lip 11 and the water suppression body 12 can be discharged from the gap G. Since the water suppression body 12 is non-contact type, lubricant is not applied to the tip of the water suppression body 12, so water, dust, and lubricant do not mix.

[0039] The seal lip 11 is contact type and expands in diameter as it goes upward. Therefore, substances located radially outward RO from the seal lip 11 are less likely to be pushed radially inward RI of the seal lip 11 and are less likely to penetrate into the bearing beyond the seal lip 11.

[0040] All descriptions of the above embodiments are illustrative and not restrictive. Various improvements and modifications can be made without departing from the scope of the present invention.

Explanation of Reference Numerals

[0041] 1 Strut bearing 2 Upper case 2A Lower surface 3 Lower case 4 Upper race 5 Lower race 6 Rolling element 7 Cage 8 Inner diameter side seal 9 Outer diameter side seal 10 Base 11 Seal lip 12 Water suppression body 13 Strut 14 Coil spring 15 Dust boot 16 Spring support part 17 Upper spring seat 18 Upper insulator 19 Upper mount A Tip part of the seal lip B Radially outer surface of the water suppression body C Wall surface D Axial gap Tip of the E1 seal lip Tips of the E2 and E3 water-repellent bodies G Gap H Difference in height J Axial direction O Rotation axis P1 First bottom surface P2 Second bottom surface Q Inner peripheral surface R Radial direction RI Radially inward RO Radially outward S Strut-type suspension

Claims

1. A strut bearing for use in a strut-type suspension of a vehicle, comprising an upper case and a lower case, an upper raceway held in the upper case, a lower raceway held in the lower case, rolling elements that roll between the upper raceway and the lower raceway, and an outer diameter side seal located radially outward of the rolling elements, The outer diameter side seal has a seal lip that is a contact type and is close to the rolling element, and a water penetration suppression body for the seal lip that is a non-contact type and is distant from the rolling element, When the rotation axis of the strut bearing is vertical, The tip of the seal lip is expanded in diameter toward the top, an upper portion of a radially outer surface of the water-receiving suppression body is a wall surface whose diameter increases upward; The lower surface of the upper case has a first lower surface having an annular shape, a second lower surface having an annular shape stepped down from the first lower surface and positioned radially outward from the first lower surface, and an inner circumferential surface connecting the first lower surface and the second lower surface, The seal lip contacts the first lower surface, and the water penetration suppression body faces the inner circumferential surface. Strut bearing.

2. A strut-type suspension for a vehicle comprising the strut bearing according to claim 1.

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