JP2504035B2 - Thrust bearing - Google Patents

Description

The present invention relates to a thrust bearing that receives a thrust load.

"Prior Art" Conventionally, for example, a thrust bearing is known, which is capable of slidingly contacting a disk-shaped thrust collar provided on a thrust shaft to receive a thrust load applied to the thrust shaft. It is also known that in a thrust bearing, in order to form an oil film satisfactorily, the sliding contact surface is formed in a middle-height shape in which the central portion projects beyond the outer peripheral portion.

"Problems to be Solved by the Invention" The above-mentioned medium-height shape of the sliding contact surface automatically becomes a middle-height shape due to the flexibility of the buff when the flatly formed sliding contact surface is buffed. When the thrust bearing is made of a material having excellent seizure resistance such as ceramics, there is a drawback in that buffing is required for a long time in order to obtain a required middle and high amount.

[Means for Solving the Problems] In view of such circumstances, the present invention is to provide a thrust bearing with a medium-high sliding contact surface in a short time even when the thrust bearing is made of a material having excellent seizure resistance such as ceramics. It is intended to provide a thrust bearing having a configuration capable of obtaining a shape.

That is, the thrust bearing of the present invention is formed by forming a concave step portion that surrounds a circular sliding contact surface on the outer periphery of the circular sliding contact surface, and forming the sliding contact surface in a spherical middle-height shape in which the central portion projects from the outer peripheral portion. is there.

[Operation] The concave step portion formed on the outer periphery of the sliding contact surface is for machining the sliding contact surface into a desired middle-height shape under the optimum conditions, as compared with the conventional product having no such step portion. Significantly reduce the processing time of.

[Examples] The present invention will be described below with reference to the illustrated examples. In Fig. 1, the thrust bearing 1 is formed in a generally cylindrical shape as a whole, and a disc provided on the thrust shaft 2 at one axial end surface thereof. A sliding contact surface 4 that slidably contacts the cylindrical thrust collar 3, and a small-diameter cylindrical projection 5 is formed on the other end surface.

The tip end surface of the projection 5 is formed into a convex curved surface, which is brought into contact with one end smooth surface 7 of the receiving member 6, and the other end surface of the receiving member 6 is brought into contact with and supported by the thrust bearing box 8. There is. Then, when the thrust load in the direction of the arrow is applied to the thrust shaft 2 and the thrust collar 3 is curved, the thrust bearing 1 is swung about the contact point between the projection 5 and the smooth surface 7 of the receiving member 6. As a result, the sliding contact surface 4 of the thrust bearing 1 can always be brought into uniform sliding contact with the thrust collar 3.

However, in the thrust bearing 1, a concave step portion 9 is formed on the outer circumference of the sliding contact surface 4 so as to surround the sliding contact surface 4, and the central portion of the sliding contact surface 4 projects within a range where an oil film is formed more than the outer peripheral portion. It is formed in a middle height.

The concave step portion 9 is formed in order to shorten the processing time for forming the sliding contact surface 4 in a middle-height shape,
In the embodiment shown in FIG. 1, in drawing, the concave step portion 9 is composed of a cylindrical surface substantially orthogonal to the sliding contact surface 4 and a plane parallel to the sliding contact surface, and the size thereof. Is exaggerated.

The corner between the cylindrical surface of the concave stepped portion 9 and the sliding contact surface 4 is formed into an arc shape by buffing when the sliding contact surface 4 is formed in a middle-height shape.

FIG. 2 shows a more prominent shape of the concave step portion, and the concave step portion 9 ′ in the present embodiment is approximately the same as the sliding contact surface 4.
A conical surface that narrows on the sliding contact surface 4 side that intersects at an angle of 10 degrees,
It is composed of a plane parallel to the sliding contact surface. In this embodiment as well, it goes without saying that the corners between the conical surface of the concave stepped portion 9'and the sliding contact surface 4 are formed in an arc shape.

Next, the effect of the concave step portions 9 and 9'will be described based on the test results. This test is the same as the product of the present invention in which the concave step portions 9 and 9'are formed as shown in FIGS. , A flat sliding surface 4 with respect to a conventional product in which such a concave step is not formed
It was measured by buffing to obtain a predetermined medium and high amount.

The material of each thrust bearing is made by sintering 99.9% alumina, and the diameter of all the products of the present invention is 14 mm.
And With respect to the concave stepped portion 9, the plane dimension in the radial direction is 2 mm, therefore the diameter of the sliding contact surface 4 is 10 mm and the height of the stepped portion 9 is 0.5 mm.

On the other hand, regarding the concave stepped portion 9 ', the radial dimension of the plane is 1 mm, the angle of the conical surface is 10 degrees with respect to the sliding contact surface 4,
Further, the height of the step 9'is 0.2 mm. The diameter of the sliding contact surface 4 at this time was about 10 mm. Further, as the concave step portion 9'having other dimensions, the radial dimension of the plane is 1 mm, the angle of the conical surface is 45 degrees with respect to the sliding contact surface 4, and the height of the step portion 9'is 1 mm. did. The diameter of the sliding contact surface 4 at this time was also about 10 mm.

Also, as a conventional product, the diameter of the sliding contact surface 4 is shown for comparison.
I prepared a 10 mm one.

When the above-mentioned machining time was measured for the above-mentioned four types of thrust bearings, the conventional product required a machining time of about 20 minutes. On the other hand, for the product of the present invention in which the concave step portion 9 is formed, the processing time is about 15 minutes, and the concave step portion 9 '
It was about 10 minutes for all the products of the present invention in which From this test result, it is understood that by forming the concave step portions 9 and 9 ', the processing time for obtaining the required middle and high amount can be significantly shortened.

The same test as above was carried out with various changes in the tilt angle in the range of 5 to 45 degrees, but there was no great change in the processing time. It has also been confirmed that the life of the sintering die is extended by about twice as long by providing the concave step portions 9 and 9 '. Further, in the above-described embodiment, the cylindrical bearing 5 having a small diameter is formed on the thrust bearing 1 and the tip end thereof is brought into contact with the smooth surface 7 of the receiving member 6, but in order to secure more excellent durability, the thrust bearing 1 The entire end surface of the bearing 1 on the protrusion 5 side is formed into a convex curved surface, the smooth surface 7 of the receiving member 6 is formed into a concave spherical surface, and the convex curved surface of the thrust bearing 1 is brought into sliding contact with the concave spherical surface of the receiving member 6. May be.

[Advantages of the Invention] As described above, in the present invention, since the concave step portion that surrounds the sliding contact surface is formed on the outer periphery of the sliding contact surface, the central portion of the sliding contact surface is formed in a middle-height shape. The processing time can be shortened at the time of forming, so that the manufacturing is facilitated and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view of an essential part showing another embodiment. 1 ... Thrust bearing, 2 ... Thrust shaft 3 ... Thrust collar, 4 ... Sliding surface, 5 ... Cylindrical protrusion, 6 ... Receiving member, 7 ... Smooth surface, 8 ... Thrust bearing box 9, 9 ′ …… Concave step

Claims (5)

(57) [Claims] 1. A circular slidable contact surface is formed with a concave step portion on the outer periphery of the circular slidable contact surface, and the slidable contact surface is formed in a spherical middle-height shape with a central portion projecting from the outer peripheral portion. Thrust bearing. 2. The thrust bearing according to claim 1, wherein the concave step portion has a cylindrical surface which is continuous with the sliding contact surface via an arcuate corner portion. 3. The recessed stepped portion has a conical surface which is continuous with the sliding contact surface via an arcuate corner and is narrowed on the sliding contact surface side. Thrust bearing described. 4. The intersection angle between the sliding contact surface and the conical surface is about 5 to 5.
The thrust bearing according to claim 3, wherein the thrust bearing is 15 degrees. 5. The thrust bearing according to claim 1, wherein the material is ceramics.