JPH0313616Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] [Field of industrial application] This invention relates to a thrust ball bearing unit, particularly a thrust ball bearing unit used in a suspension system of an automobile.

[Prior Art] Metal thrust ball bearings have traditionally been incorporated into automobile McPherson strut suspension systems, but the mating members that come into contact with the thrust ball bearings are mostly made of sheet metal. In some cases, the dimensional accuracy such as flatness was poor, and the contact surface with the thrust ball bearing came into contact (contact), causing fretting corrosion due to minute slippage, which caused problems such as noise generation. . Additionally, the environment inside the tire house where the thrust ball bearing is installed is extremely poor, with muddy water flying around, and rust or dust entering the rolling surfaces, causing damage to the rolling surfaces and rolling elements.

Therefore, a thrust ball bearing has been proposed in which a metal thrust ball bearing is housed in a synthetic resin case to form a unit.

FIG. 7 is a longitudinal sectional view showing a thrust ball bearing unit in which a metal thrust ball bearing is housed in a synthetic resin case.

The thrust ball bearing 7 is composed of bearing rings 1 and 2 and rolling elements 4 disposed between the bearing rings 1 and 2. The bearing rings 1 and 2 are each made of synthetic resin, and
It is housed in lower cases 12 and 13, and the upper case 12 seals and covers the inner and outer peripheral edges of the lower case 13.

FIG. 8 is a longitudinal sectional view showing an example in which the thrust ball bearing unit is incorporated into a MacPherson strut type suspension system for an automobile.

In the figure, a rod end plate 32 is integrally fixed to an upper mount 34 fixed to a body 33 with a mounting bolt/nut 47 via a rubber mount 35, and a shock absorber main body is attached to the end plate 32. 4
3 is fixed in its rod 37 by a nut 38. The upper mount 34 also serves as a bearing holder, and the upper mount 34 also serves as a bearing holder.
The synthetic resin upper case 12 of the thrust ball bearing unit is fitted into the cylindrical recess 45 of No. 4. A cylindrical portion 41 of a spring seat 39 is fitted into the inner diameter side of the synthetic resin lower case 13 of the thrust ball bearing unit, and one end of the coil spring 42 of the suspension device is fitted into the spring seat 39 with an elastic sheet 40 made of rubber or the like. It is fitted through. The other end of the coil spring 42 is supported by a spring seat 44 provided on the shock absorber body 43.

When such a thrust ball bearing unit is used by being incorporated into a suspension system, it is necessary to make a recess 46 in the upper case 12 in order to accommodate the bolt head of the mounting bolt/nut 47 in the upper mount 34. be. Typically, the recesses 46 are provided at two locations across the diameter. In a thrust ball bearing unit, the dimensional accuracy, especially the flatness, of the mating member in which the unit is housed is strictly required, but since the upper mount 34 is usually formed of sheet metal, the dimensional accuracy cannot be satisfied. Instead, damage occurs due to stress concentration, such as partial impact on the raceway rings 1 and 2, which causes indentations. For this reason, some have a structure in which a separate member with sufficient flatness and flatness is placed on the upper mount 34 or spring seat 39.

In addition, in the case of the above structure, the bolt/nut 47 that fastens the upper mount 34 and the body 33
Because of the bolt heads, the upper case 12 has a non-uniform wall thickness, which has the drawback of being prone to warping during manufacturing.

Therefore, as shown in FIG. 9, an annular groove 49 is provided on the surface of the upper case 12 that contacts the bearing ring 1, and a large number of radial protrusions 51 are provided around the bearing center.
As shown in FIG. 10, which is a cross-sectional view developed along the circumference along the sectional line A--A in FIG. 9, a bearing ring 1 can be seen in which the bearing ring 1 is brought into contact with the protrusion 51.

In this case, the body 33 and upper mount 34
The above-mentioned protrusion 51 is eliminated from the part where the fastening bolt head is located, so that the wall thickness can be made uniform.

[Problems that the invention aims to solve] In the thrust ball bearing unit shown in FIG. Although the upper case 12 is made of synthetic resin, it is recognized that the load is applied unevenly to the thrust ball bearing 7. This is because the protrusion 51 is integrally and continuously formed within the upper case 12 and on the inner surface of the outer peripheral cylindrical hanging parts 21', 21, so that the upper case 12 conforms to the unevenness of the seat surface of the upper mount 34. Even if the deformation is caused by the protrusion 51,
This in turn acts on the bearing ring 1 that abuts the protrusion 51, resulting in uneven contact and damage caused by stress concentration, such as indentations on the bearing rings 1 and 2, which have not yet been resolved.

The object of this invention is to provide a thrust ball bearing unit that solves the above-mentioned problems with thrust ball bearing units housed in a synthetic resin case and has the ability to improve the state of contact with a mating member.

[Structure of the invention] [Means for solving the problem] This invention consists of an upper and lower case made of synthetic resin;
It consists of metal upper and lower bearing rings held in a lower case, respectively, and rolling elements arranged between the raceway surfaces of the upper and lower bearing rings, and the upper case has a ring plate-shaped base and the ring plate-shaped base. The lower case includes an inner and outer cylindrical hanging portion formed on the outer periphery and an engaging lip portion formed at the lower end of the inner and outer cylindrical hanging portion, and the lower case includes a ring plate-shaped base and the ring plate. The upper case is provided with an inner and outer cylindrical protrusion formed on the inner and outer periphery of the shaped base, and an engaging lip portion formed at the upper end of the inner and outer cylindrical protrusion, and the upper case is formed on the inner and outer periphery of the cylindrical protrusion. The lower end engaging lip portion of the lower case is elastically attached to the upper end engaging lip portion of the outer circumferential cylindrical protrusion inside the lower case to combine with the lower case, and the elastic attaching portion has a sealing portion by a labyrinth action. In this thrust ball bearing, a plurality of radial protrusions are formed in the circumferential direction on the upper surface of the annular plate-shaped base of the upper case and/or the lower surface of the annular plate-shaped base of the lower case, which contact the mating member. This is a thrust ball bearing unit characterized by:

[Operation] Even if there is non-uniformity in dimensional accuracy such as flatness or flatness of the mating member, the dimensional accuracy is maintained in the radial protrusion formed on the upper surface of the annular base of the upper case that comes into contact with the mating member. This absorbs uneven contact and stress concentration due to uneven dimensional accuracy of the bearing rings held in the upper and lower cases and the rolling elements arranged between the raceway surfaces of the bearing rings. No such problems will occur.

[Example] Hereinafter, this invention will be explained in detail with reference to the accompanying drawings showing examples thereof.

FIG. 1 is a longitudinal sectional view showing the thrust ball bearing unit of this invention, and FIG. 2 is a plan view of FIG. 1.

The metal upper bearing ring 1 has its outer diameter D ₁ and inner diameter
d ₁ is slightly larger than the outer diameter D 2 and _{the inner diameter d 2 of} the metal lower bearing ring 2 facing the upper bearing ring 1, and the upper bearing ring 1
The outer diameter D ₁ of the bearing ring 1 is formed to be exactly concentric with the raceway surface 8 of the bearing ring 1, and the inner diameter d ₂ of the lower bearing ring 2 is formed to be exactly concentric with the raceway surface 9 of the bearing ring 2.

The end face 5 of the upper raceway 1 and the lower raceway 2
The end surface 11, in other words, the surface opposite to the surface on which the raceway surfaces 8 and 9 are formed, each forms a plane perpendicular to the axis, and the end surfaces 5 and 11 and the inner and outer surfaces that are continuous with the end surfaces 5 and 11 Each corner with the radial surface is chamfered. Raceway surfaces 8 and 9 formed on the upper and lower raceway rings 1 and 2 each have an arcuate cross section with a radius slightly larger than the radius of the balls forming the rolling elements 4.

The rolling elements 4 are rotatably held between the raceway surfaces 8 and 9 of the upper and lower bearing rings 1 and 2.

The upper case 12 is made of synthetic resin, such as polyacetal resin or polyamide resin, and the upper case 12 has a ring plate-shaped base 24 and inner and outer cylinders formed on the inner and outer peripheral edges of the ring plate-shaped base 24. Hanging parts 16, 21 and the inner and outer cylindrical hanging parts 1
The engaging lip portion 17 formed at the lower end of 6, 21,
22, a downward circumferential groove 6 formed on the lower surface of the base, that is, the lower surface of the base surrounded by the inner and outer cylindrical hanging parts 16 and 21, and a downward circumferential groove 6 formed on the upper surface of the annular plate-shaped base 24 in the circumferential direction thereof. A plurality of radial protrusions 2
5.

The engaging lip portion 17 formed at the lower end of the inner cylindrical hanging portion 16 has an inclined surface portion facing outward in the radial direction, and the engaging lip portion 22 formed at the lower end of the outer cylindrical hanging portion 21 has an inclined surface portion facing outward in the radial direction. It has an inclined surface portion facing in the radial direction.

The upper bearing ring 1 has an end face 5 connected to the upper case 12.
The upper case 12 is held by being fitted into a circumferential groove 6 formed on the lower surface of the base 24 of the upper case 12 .

The lower case 13 is made of the same synthetic resin as the upper case 12.
has a ring-shaped base 28 and a stepped portion 1 on the inner peripheral edge of the base 28;
8 and an outer cylindrical protrusion 23 formed on the outer periphery of the base 28.
and engaging lip portions 15 and 20 formed on the upper ends of the inner and outer cylindrical protrusions 14 and 23, respectively, and a plurality of radial protrusions formed on the lower surface of the annular plate base 28 in the circumferential direction thereof. It is equipped with 29.

The engagement lip 15 formed at the upper end of the inner cylindrical protrusion 14 has a sloping surface facing radially inward, and the engagement lip 20 formed at the upper end of the outer cylindrical protrusion 23 has a radially inward slope. It has an inclined surface portion facing outward in the radial direction.

The lower bearing ring 2 has an end face 11 connected to the lower case 1.
3, it is fitted into the cylindrical part 10 in contact with the upper surface of a ring plate-shaped base 28 surrounded by the outer circumferential cylindrical protrusions 14 and 23, and is held in the lower case 13.

In the above-described configuration, the inner diameter d ₄ of the inner cylindrical projecting portion 14 of the lower case 13 is slightly smaller than the inner diameter d ₃ of the inner cylindrical hanging portion 16 of the upper case 12 .

The upper and lower cases 12 and 13 holding the upper and lower bearing rings 1 and 2 respectively hold the rolling elements 4 between the raceway surfaces 8 and 9 of the upper and lower bearing rings 1 and 2,
Inside the upper case 12, the outer peripheral cylindrical hanging portions 16, 2
The lower end engaging lip portions 17, 22 of the lower case 13 are elastically attached (snap fit) to the upper end engaging lip portions 15, 20 of the outer peripheral cylindrical projections 14, 23, respectively.

In the thrust ball bearing unit combined in this way, a sealing part is formed by a labyrinth effect on each of the elastic mounting parts on the outer circumferential surface of the unit, and this prevents dust etc. from entering into the sliding surface of the thrust ball bearing 7. be done.

Note that the reference numeral 46 in the figure is a recess formed in the upper surface of the annular plate-shaped base of the upper case 12 so as to face each other in the radial direction. This is to prevent the bolt head of the bolt/nut 47 from being hit. Depending on the structure of the strut, the bolt head may not protrude from the bearing surface of the thrust ball bearing, and in such cases there is no need to provide this recess 46.

FIG. 3 is a longitudinal sectional view showing another embodiment of this invention, in which the radial protrusions are connected to the upper case 1.
It is formed only on the upper surface of the annular plate-shaped base 24 of No. 2,
The other configurations are the same as those of the previous embodiment.

FIG. 4 is a longitudinal cross-sectional view showing still another embodiment of this invention, in which an annular protrusion 26 is provided on the upper surface of the annular plate-shaped base 24 of the upper case 12, on the inner and outer peripheral edges of the base 24, respectively. 27 and a plurality of radial protrusions 25 in the circumferential direction continuous with the annular protrusions 26, 27.
7, and the other configurations are the same as those of the previous embodiment.

FIG. 5 shows still another embodiment of this invention, in which radial protrusions 25, 29 having a trapezoidal longitudinal section are provided on the upper surface of the annular plate-shaped base 24 of the upper case 12 and on the lower surface of the annular plate-shaped base 28 of the lower case 13. The width W of the portion that contacts the mating member is approximately equal to the width of the thrust ball bearing 7, and the other configurations are the same as those of the previous embodiment.

A case where the thrust ball bearing unit constructed from the embodiment shown in FIGS. 1 and 2 described above is installed in the suspension system of an automobile shown in FIG. 6 will be described.

The thrust ball bearing unit is attached to the lower case 13 in the cylindrical portion 41 of the spring seat 39.
The inner circumferential surfaces of the upper case 1 are fitted together, and the radial protrusion 29 on the lower surface of the annular base 28 of the lower case 13 is seated on the spring seat 39.
2 to the cylindrical part 4 of the upper mount 34.
5, and the radial protrusion 25 on the upper surface of the annular plate base 24 of the upper case 12 is seated on the mount 34 to be assembled.

In the thrust ball bearing unit assembled in this way, even if the spring seat 39 and the upper mount 34, which are made of sheet metal and are mating members of the bearing unit, have uneven surfaces, the upper and lower cases 12, 13 Since the radial protrusions formed on the ring plate-shaped base of the ring deform along with the irregularities, uneven loads are applied to the bearing rings 1 and 2, and eventually to the rolling elements 4 arranged between the raceway surfaces of the bearing rings. Never give up.

[Effects of the Invention] The thrust ball bearing unit of this invention having the above-mentioned configuration has the following unique effects.

Even if the mating member into which the thrust ball bearing unit is incorporated has uneven dimensional accuracy such as flatness and flatness, the upper surface of the annular plate-shaped base of the upper case and/or the annular plate-shaped base of the lower case that comes into contact with the mating member. Since the radial protrusions formed on the lower surface of the base absorb the non-uniformity of the dimensional accuracy, the bearing ring held in the lower case and the rolling elements arranged between the raceway surfaces of the bearing ring. uneven contact due to uneven dimensional accuracy;
No problems such as stress concentration occur.

The upper and lower cases are assembled together by being elastically mounted on the outer circumference side, and a labyrinth sealed portion is formed in the elastic mounting portion to prevent dust from entering the sliding surface.

Since the upper and lower cases are assembled together by being elastically attached on their outer peripheral surfaces, the assembly work is improved and the workability of assembling them into the suspension system is also improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of this invention, FIG. 2 is a plan view of FIG. 1, FIGS. 3 to 5 are longitudinal sectional views showing other embodiments, and FIG. 1 is a vertical sectional view of the embodiment shown in FIG. 1 incorporated into a suspension system, FIGS. 7 to 9 are vertical sectional views showing conventional examples, and FIG. 10 is a developed view of the A-A cross section in FIG. 9. . DESCRIPTION OF SYMBOLS 1...Upper bearing ring, 2...Lower bearing ring, 4...Rolling element, 12...Synthetic resin upper case, 13...Synthetic resin lower case, 14...Inner cylindrical protrusion, 16...
Inner circumferential cylindrical hanging portion, 15, 17, 20, 22... Engaging lip portion, 21... Outer circumferential cylindrical hanging portion, 23... Outer circumferential cylindrical protruding portion, 25, 29... Radial protruding portion.

Claims (1)

[Scope of utility model registration request] synthetic resin upper and lower cases 12 and 13;
Metal upper and lower bearing rings 1 and 2 held in a lower case, respectively, and raceway surfaces 8 of the upper and lower bearing rings,
The upper case 12 consists of a ring plate-shaped base 24 and inner and outer cylindrical hanging parts 16, 21 formed on the outer periphery of the ring plate-shaped base.
The lower case 13 includes an annular plate-shaped base 28 and engaging lip parts 17 and 22 formed on the inner and outer peripheral edges of the annular plate-shaped base. The upper case 1 includes inner and outer cylindrical protrusions 14 and 23 and engagement lips 15 and 20 formed at the upper ends of the inner and outer cylindrical protrusions.
2 connects the lower end engaging lip parts 17 and 22 of the inner and outer peripheral cylindrical hanging parts 16 and 21 to the upper end engaging lip part 1 of the inner and outer peripheral cylindrical protruding parts 14 and 23 of the lower case 13.
5 and 20, respectively, and is combined with the lower case 13, and a sealing part by a labyrinth action is formed in the elastic mounting part. A plurality of radial protrusions 2 are provided on the upper surface of the plate-shaped base 24 and/or the lower surface of the annular plate-shaped base 28 of the lower case 13 in the circumferential direction.
5, 29 are formed.