Strut bearing device, and strut-type suspension of vehicle

Abstract

To enhance the effect of decelerating high-speed water, such as slurry, intruding from the outside in a radial direction into a clearance in a shaft direction, until the water reaches an outer diameter side seal.SOLUTION: The first wall surface 3A of a lower side case is an outer peripheral surface facing a shaft direction clearance C. The second wall surface 3B of the lower side case is an annular surface extending from an upper end of the first wall surface 3A of the lower side case to the radial direction outside RO. The third wall surface 3C of the lower side case is an outer peripheral surface extending from an end E of the radial direction outside RO of the second wall surface 3B of the lower side case to an upper side. The first wall surface 2A of an upper side case is an inner peripheral surface facing an upper part of the first wall surface 3A of the lower side case. The second wall surface 2B of the upper side case is an annular surface extending from an upper end of the first wall surface 2A of the upper side case to the radial direction inside RI. The third wall surface 2C of the upper side case is an inner peripheral surface which extends from an end F of the radial direction inside RI of the second wall surface 2B of the upper side case to the upper side, and which faces the third wall surface 3C of the lower side case.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a strut bearing device for use in a strut-type suspension of a vehicle. [Background technology]

[0002] One type of suspension that supports the wheels on the vehicle body with coil springs and has shock absorbers to absorb vertical vibrations is the strut suspension, which has an expandable pillar (strut) with a built-in shock absorber attached to the axle. Strut suspensions are widely used mainly for the front wheels of passenger cars.

[0003] A strut bearing device for use on the upper part of a strut suspension has an upper case made of synthetic resin that holds an upper raceway (e.g., upper cap 3 in Patent Document 1), a lower case made of synthetic resin that holds a lower raceway (e.g., lower cap 4 in Patent Document 1), and an inner diameter side seal made of elastomer that is a seal located radially inward of the rolling elements provided in the lower case (e.g., inner seal 6 in Patent Document 1), and an outer diameter side seal made of elastomer that is a seal located radially outward of the rolling elements (e.g., outer seal 7 in Patent Document 1) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 10,753,389 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the upper case and the lower case are made of synthetic resin, and therefore, in order to eliminate abnormal noise and increased torque caused by contact between them, axial and radial gaps of required sizes are provided between the upper and lower cases.

[0006] The strut bearing device is used in a severe muddy water environment where it is directly exposed to muddy water from the road surface splashed up by the wheels, etc. Furthermore, when a high-pressure washer is used for washing the car, the strut bearing device is exposed to high-pressure water discharged from the high-pressure washer when washing the undercarriage of the car.

[0007] Therefore, for example, in the strut bearing device of Patent Document 1, if high-speed water such as muddy water enters the axial gap between the upper cap 3 and the lower cap 4 from the outer diameter side, the water will rise along the outer peripheral surface of the lower cap 4 and reach the outer seal 7 without sufficiently slowing down, causing the outer seal 7 to become wet, which may reduce the sealing performance.

[0008] The present invention aims to provide a strut bearing device that can improve the effect of slowing down high-speed water, such as muddy water, that has entered the axial gap between the upper case and lower case, or the axial gap between the upper case and upper spring seat from the outside in the radial direction, before it reaches the outer diameter side seal. [Means for solving the problem]

[0009] A strut bearing device according to a first aspect of the present invention is a strut bearing device including a strut bearing and an upper spring seat which is a spring support part that supports the upper end of a coil spring. The strut bearing includes 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 which roll between the upper raceway and the lower raceway, and a seal located radially outward of the rolling elements. The upper spring seat contacts the lower case. An axial gap is present between the upper case and the upper spring seat. The upper case has an upper case first wall surface, an upper case second wall surface, and an upper case third wall surface. The lower case has a lower case first wall surface, a lower case second wall surface, and a lower case third wall surface. The lower case first wall surface is an outer circumferential surface which faces the axial gap. The lower case second wall surface is an annular surface extending radially outward from an upper end of the lower case first wall surface. The lower case third wall surface is an outer peripheral surface extending upward from a radially outer end of the lower case second wall surface. The upper case first wall surface is an inner peripheral surface facing an upper portion of the lower case first wall surface. The upper case second wall surface is an annular surface extending radially inward from an upper end of the upper case first wall surface. The upper case third wall surface is an inner peripheral surface facing the lower case third wall surface, extending upward from a radially inner end of the upper case second wall surface.

[0010] A strut bearing device according to a second aspect of the present invention includes an upper case and a lower case, an upper raceway held by the upper case, a lower raceway held by the lower case, rolling elements rolling between the upper raceway and the lower raceway, and a seal positioned radially outward of the rolling elements. The lower case is made of synthetic resin with a core metal built in, has a cylindrical portion and an annular portion extending radially outward from an upper portion of the cylindrical portion, and functions as a spring support part supporting an upper end of a coil spring. An axial gap is provided between the upper case and the lower case. The upper case has an upper case first wall surface, an upper case second wall surface, and an upper case third wall surface. The lower case has a lower case first wall surface, a lower case second wall surface, and a lower case third wall surface. The lower case first wall surface is an outer peripheral surface facing the axial gap. The lower case second wall surface is an annular surface extending radially outward from an upper end of the lower case first wall surface. The lower case third wall surface is an outer peripheral surface extending upward from a radially outer end of the lower case second wall surface. The upper case first wall surface is an inner peripheral surface facing an upper portion of the lower case first wall surface. The upper case second wall surface is an annular surface extending radially inward from an upper end of the upper case first wall surface. The upper case third wall surface is an inner peripheral surface facing the lower case third wall surface, extending upward from a radially inner end of the upper case second wall surface.

[0011] A strut bearing device according to a third aspect of the present invention is a strut bearing device according to the first or second aspect, wherein the angle formed between the lower case first wall surface and the lower case second wall surface and / or the angle formed between the upper case first wall surface and the upper case second wall surface is an acute angle.

[0012] A strut suspension for a vehicle according to a fourth aspect of the present invention comprises the strut bearing device according to the first or second aspect. Effect of the Invention

[0013] According to the strut bearing device and vehicle strut suspension of the present invention described above, the upper case has the upper case first wall surface, the upper case second wall surface, and the upper case third wall surface, and the lower case has the lower case first wall surface, the lower case second wall surface, and the lower case third wall surface.

[0014] When high-velocity water such as muddy water infiltrates through the axial gap, the high-velocity water bounces off after hitting the lower case first wall surface, which is the outer peripheral surface facing the axial gap, and hits the upper case first wall surface, which is the inner peripheral surface.The water flow toward the outer diameter side seal, which is a seal located radially outward of the rolling elements, hits the upper case second wall surface, which is an annular surface, and then passes through the radial gap between the lower case third wall surface and the upper case third wall surface.

[0015] Therefore, the high-speed water hits the lower case first wall surface which is the outer circumferential surface facing the axial gap, the upper case first wall surface which is the inner circumferential surface, and the upper case second wall surface which is the annular surface, and the water force is attenuated and the direction of the water flow is dispersed, and then the water passes through the radial gap and approaches the outer diameter side seal. Therefore, it is possible to enhance the effect of decelerating high-speed water such as muddy water that has entered the axial gap from the radial outside before it reaches the outer diameter side seal. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic partial cross-sectional view of a strut suspension for a vehicle equipped with a strut bearing device according to a first embodiment of the present invention. [Diagram 2] 2 is an enlarged longitudinal sectional view of a main portion showing the strut bearing device and an upper insulator. FIG. [Diagram 3] FIG. 4 is an enlarged longitudinal sectional view of a main portion showing a structure around an axial gap. [Figure 4] FIG. 11 is an enlarged longitudinal sectional view of a main part showing a first modified example. [Diagram 5] FIG. 11 is an enlarged longitudinal sectional view of a main portion showing a second modified example. [Figure 6] FIG. 13 is an enlarged longitudinal sectional view of a main portion showing a third modified example. [Figure 7] FIG. 6 is an enlarged longitudinal sectional view of a main portion showing a strut bearing device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

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

[0019] [Embodiment 1] <Strut suspension> The strut suspension S of a vehicle shown in FIG. 1 is used with an expandable strut 10 incorporating a shock absorber fixed to an axle (not shown), and an upper mount 16 fixed to the vehicle body.

[0020] The upper part of the strut suspension S is provided with a strut bearing 1 which supports the vehicle body and oscillates and rotates as the direction of the steered wheels changes due to steering operation. The oscillating angle of the strut bearing 1 is determined according to the allowable steering angle of the wheels, and is set, for example, in the range of 40° to 50°.

[0021] A coil spring 11, which is a suspension spring, and a dust boot 12 for protecting the oil seal of the shock absorber from foreign matter such as sand are provided on the radially outer side RO of the strut 10. The strut suspension S includes a spring support part 13 that supports the upper end of the coil spring 11. The spring support part 13 consists of an upper spring seat 14 and an upper insulator 15.

[0022] <Strut bearing device> As shown in FIGS. 1 and 2, a strut bearing device A according to a first embodiment of the present invention includes a strut bearing 1 and an upper spring seat 14 which is a spring support component 13 that supports the upper end of a coil spring 11.

[0023] The strut bearing 1 includes an upper case 2, a lower case 3, an upper raceway 4, an upper raceway 5, rolling elements 6, a cage 7, an inner diameter side seal 8, an outer diameter side seal 9, and the like.

[0024] The upper case 2 is fixed to the upper end of the strut 10, and the lower case 3 receives an upper spring seat 14 from above. The upper raceway 4 is held in the upper case 2, and the lower raceway 5 is held in the lower case 3. The rolling elements 6 roll between the upper raceway 4 and the lower raceway 5, and the cage 7 holds the rolling elements 6 so that adjacent rolling elements 6 do not come into contact with each other.

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

[0026] The upper and lower races 4, 5 and upper spring seat 14 are made of steel and are formed by pressing steel plates. The upper and lower cases 2, 3 are made of synthetic resin, and the inner and outer seals 8, 9 are made of elastomer.

[0027] The synthetic resin used for the upper case 2 and the lower case 3 is, for example, a polyamide resin (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 type), TPO (olefin type), TPU (urethane type), TPA (amide type), TPEE (ester type), etc., and the rubber materials are nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), fluororubber (FKM, FPM), silicone rubber (VQM), etc. The rubber materials can be one type or a suitable blend of two or more types of rubber.

[0029] <Structure for slowing down high-speed water that enters through the axial gap> 2 and 3, there is an axial gap C between the upper case 2 and the upper spring seat 14. The upper case 2 has an upper case first wall surface 2A, an upper case second wall surface 2B, and an upper case third wall surface 2C. The lower case 3 has a lower case first wall surface 3A, a lower case second wall surface 3B, and a lower case third wall surface 3C.

[0030] The lower case first wall surface 3A is an outer peripheral surface facing the axial gap C. The lower case second wall surface 3B is an annular surface extending radially outward RO from an upper end of the lower case first wall surface 3A. The lower case third wall surface 3C is an outer peripheral surface extending upward from an end E of the lower case second wall surface 3B in the radially outward RO.

[0031] The upper case first wall surface 2A is an inner peripheral surface facing the upper part of the lower case first wall surface 3A. The upper case second wall surface 2B is an annular surface extending radially inward RI from the upper end of the upper case first wall surface 2A. The upper case third wall surface 2C is an inner peripheral surface facing the lower case third wall surface 3C, extending upward from an end F of the upper case second wall surface 2B in the radially inward RI.

[0032] In the examples of FIGS. 2 and 3, the upper case first wall surface 2A faces the upper part of the lower case first wall surface 3A, the end E in the radially outward RO of the lower case second wall surface 3B, and the lower part of the lower case third wall surface 3C. Further, the lower case third wall surface 3C faces the lower part of the upper case third wall surface 2C, the end F in the radially inward RI of the upper case second wall surface 2B, and the upper part of the upper case first wall surface 2A. Therefore, the water flow toward the outer diameter side seal 9 passes from the first radial gap G1 between the lower case third wall surface 3C and the upper case first wall surface 2A through the second radial gap G2 between the lower case third wall surface 3C and the upper case third wall surface 2C, which has a smaller diameter than the first radial gap G1.

[0033] The axial lengths J1, J2, J3, J4 shown in FIG. 3 are such that J1 < J2 < J3 < J4, but J2 = J3 may also be possible. That is, it is sufficient that J1 < J2 ≦ J3 < J4. When J2 = J3, the end E in the radially outward RO of the lower case second wall surface 3B and the end F in the radially inward RI of the upper case second wall surface 2B face each other in the radial direction R.

[0034] Also, the radii R1, R2, R3, R4 shown in FIG. 3 are such that R1 < R2 < R3 < R4. In a preferred embodiment, the length in the radial direction R of the second radial gap G2, that is, R3 - R2, is 2.0 mm or less.

[0035] <Function and effect> When high-speed water such as muddy water enters from the axial gap C, the high-speed water hits the lower case first wall surface 3A, which is the outer peripheral surface facing the axial gap C, and bounces back, hits the upper case first wall surface 2A, which is the inner peripheral surface, and the water flow toward the outer diameter side seal 9 hits the upper case second wall surface 2B, which is an annular surface, and then passes through the second radial gap G2 between the lower case third wall surface 3C and the upper case third wall surface 2C.

[0036] Therefore, the high-speed water hits the lower case first wall surface 3A, which is the outer peripheral surface facing the axial gap C, the upper case first wall surface 2A, which is the inner peripheral surface, and the upper case second wall surface 2B, which is the annular surface, and the water force is attenuated and the direction of the water flow is dispersed, and then the water approaches the outer diameter side seal 9 through the second radial gap G2. This can enhance the effect of decelerating high-speed water such as muddy water that has infiltrated into the axial gap C from the radially outward RO before it reaches the outer diameter side seal 9. This can reduce the amount of water flow that reaches the periphery of the lip of the outer diameter side seal 9.

[0037] <Modification> In a preferred embodiment, the lower case second wall surface 3B, which is a circular toric surface, is inclined downward as it moves radially outward RO, and the angle P formed with the lower case first wall surface 3A is an acute angle (P<90°), as shown in Fig. 4. In a preferred embodiment, the upper case second wall surface 2B, which is a circular toric surface, is inclined downward as it moves radially inward RI, and the angle Q formed with the upper case first wall surface 2A is an acute angle (Q<90°), as shown in Fig. 5.

[0038] By making angle P and / or angle Q an acute angle, the effect of slowing down high-speed water such as muddy water that has entered the axial gap C from the radially outward RO before it reaches the outer diameter side seal 9 is further increased.

[0039] For example, in the structure of Fig. 2, a circular ring-shaped inward protrusion H protruding radially inward RI as shown in Fig. 6 may be provided at the lower end of the upper case 2. By providing the inward protrusion H, it is possible to prevent the upper case 2 and the lower case 3 from being separated.

[0040] <Analysis to compare the flow speed of infiltrating muddy water, etc.> (Analysis model) An analytical model of the present invention that mimics the shape of the strut bearing device A in FIG. 6 and a conventional-shaped analytical model that mimics the shape of the strut bearing device in FIG. 1 of Patent Document 1 were created. At the axial length shown in FIG. 3, in the analytical model of the present invention, J3 < J4, and in the analytical model of the conventional shape, J3 > J4. For the analytical model of the present invention and the analytical model of the conventional shape, a comparison was made of the flow velocity at the lip periphery of the outer diameter side seal 9 of the water that had entered from the axial clearance C.

[0041] (Analysis conditions) For ease of analysis, an underwater environment was assumed, and an injection port (diameter 2 mm) for injecting water was arranged radially inward RI toward the radially outer side RO of the axial clearance C, and analysis was performed under the condition of injecting high-speed water with a flow velocity of 8 m / s from the injection port.

[0042] (Analysis results) The flow velocity at the lip periphery of the outer diameter side seal 9 was 0.80 for the analytical model of the present invention, with the analytical model of the conventional shape being set as 1.0. It can be seen that the present invention can enhance the effect of decelerating the high-speed water that has entered the axial clearance C until it reaches the outer diameter side seal 9.

[0043] [Embodiment 2] <Strut bearing device> In the strut bearing device B according to Embodiment 2 of the present invention shown in FIG. 7, the same reference numerals as those in FIGS. 1 to 3 of Embodiment 1 indicate the same or corresponding components, parts, locations, etc.

[0044] The lower case 3 of the strut bearing 1, which is the strut bearing device B, is made of a synthetic resin containing a mandrel M. The mandrel M is made of steel, formed by pressing from a steel plate, and hardened by quenching after processing as necessary. The lower case 3 is formed by injection molding with the mandrel M as an insert work.

[0045] The lower case 3 has a cylindrical portion 3D and an annular portion 3E extending radially outward RO from the upper part of the cylindrical portion 3D, and by incorporating a core wire M, it functions as an upper spring seat of the spring support part 13 that supports the upper end of the coil spring 11 (see Figure 1).

[0046] There is an axial gap D between the upper case 2 and the lower case 3. Upper case first wall surface 2A, upper case second wall surface 2B, and upper case third wall surface 2C of upper case 2, and lower case first wall surface 3A, lower case second wall surface 3B, and lower case third wall surface 3C of lower case 3 are the same as in embodiment 1. Therefore, strut bearing device B of embodiment 2 provides the same effects as strut bearing device A of embodiment 1.

[0047] The above description of the embodiments is given by way of example only and is not intended to be limiting, and various improvements and modifications can be made without departing from the scope of the present invention. [Explanation of symbols]

[0048] 1 Strut Bearing 2 Upper case 2A Upper case first wall 2B Upper case second wall 2C Upper case third wall 3 Lower case 3A Lower case first wall 3B Lower case second wall 3C Lower case third wall 3D Cylinder 3E Circular section 4 Upper raceway 5 Lower raceway 6 Rolling elements 7 Cage 8 Inner diameter seal 9 Outer diameter seal 10 Strut 11 Coil spring 12 Dust Boots 13 Spring support parts 14 Upper spring seat 15 Upper insulator 16 Upper mount A,B Strut bearing device C,D Axial clearance E Radial outer end of the second wall of the lower case F: Radial inner end of the second wall of the upper case G1 First radial clearance G2 Second radial clearance H Inner protrusion J-axis direction J1, J2, J3, J4 axial length M Core O Rotation axis P,Q angle R Radial direction R1,R2,R3,R4 radius RI radially inward RO radially outward S Strut suspension

Claims

1. A strut bearing device including a strut bearing and an upper spring seat which is a spring support part that supports an upper end of a coil spring, The strut bearing includes an upper case and a lower case, an upper raceway ring held in the upper case, a lower raceway ring held in the lower case, rolling elements that roll between the upper raceway ring and the lower raceway ring, and a seal located radially outward of the rolling elements, The upper spring seat contacts the lower case, An axial gap is provided between the upper case and the upper spring seat. the upper case has an upper case first wall surface, an upper case second wall surface, and an upper case third wall surface, the lower case has a lower case first wall surface, a lower case second wall surface, and a lower case third wall surface, the lower case first wall surface is an outer circumferential surface facing the axial gap, the lower case second wall surface is an annular surface extending radially outward from an upper end portion of the lower case first wall surface, the lower case third wall surface is an outer circumferential surface extending upward from a radially outer end portion of the lower case second wall surface, the upper case first wall surface is an inner circumferential surface facing an upper portion of the lower case first wall surface, the upper case second wall surface is an annular surface extending radially inward from an upper end portion of the upper case first wall surface, The upper case third wall surface is an inner circumferential surface that extends upward from a radially inner end portion of the upper case second wall surface and faces the lower case third wall surface. Strut bearing assembly.

2. A strut bearing device comprising an upper case and a lower case, an upper raceway ring held in the upper case, a lower raceway ring held in the lower case, rolling elements that roll between the upper raceway ring and the lower raceway ring, and a seal located radially outward of the rolling elements, the lower case is made of synthetic resin with a core metal built in, has a cylindrical portion and an annular portion extending radially outward from an upper portion of the cylindrical portion, and functions as a spring support part that supports an upper end of a coil spring; There is an axial gap between the upper case and the lower case, the upper case has an upper case first wall surface, an upper case second wall surface, and an upper case third wall surface, the lower case has a lower case first wall surface, a lower case second wall surface, and a lower case third wall surface, the lower case first wall surface is an outer circumferential surface facing the axial gap, the lower case second wall surface is an annular surface extending radially outward from an upper end portion of the lower case first wall surface, the lower case third wall surface is an outer circumferential surface extending upward from a radially outer end portion of the lower case second wall surface, the upper case first wall surface is an inner circumferential surface facing an upper portion of the lower case first wall surface, the upper case second wall surface is an annular surface extending radially inward from an upper end portion of the upper case first wall surface, The upper case third wall surface is an inner circumferential surface that extends upward from a radially inner end portion of the upper case second wall surface and faces the lower case third wall surface. Strut bearing assembly.

3. an angle formed between the lower case first wall surface and the lower case second wall surface and / or an angle formed between the upper case first wall surface and the upper case second wall surface is an acute angle; 3. A strut bearing device according to claim 1 or 2.

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

Images