The invention is related to a ball rolling bearing with a separator separating the balls.

Rolling bearings are used as structural elements of machine parts. Construction of the rolling bearings is differentiated, however in each case they include two rolling elements that move between two races. Additional elements of rolling bearing may include: separators keeping the rolling elements in fixed mutual distance, sealings, etc.

Rolling bearings ensure rotary motion of a shaft and maintain fixed position of its rotation axis and transfer loads therefore they should characterize with low movement resistance, stable operation, reliability of operation and wearing resistance, i.e. high durability. In order to get as low energy losses due to friction as possible and reduction of noise due to mating parts vibration, races of the structural elements cooperating with rolling elements are ground and then honed. However, a major problem is caused by small differences in the rolling elements dimensions. The mass produced rolling elements are selected from the standpoint of their size but the achievement of absolute uniformity of the rolling elements dimensions is practically impossible. For example, the ball rolling bearing is equipped with balls of diameters that mutually differ by 2 pm. In the assembled bearing, rotating at speed e.g. 1000 rpm, the balls move along the races and within 1 minute the distance the pass may differ by even 20 mm. Non-uniform load on rolling elements of a bearing cause further differences in the distance passed by the rolling element. In case of rolling bearings that transfer only the transverse load, the rolling elements that do not transfer loads move and balance the passed distance. In case of bearings where all rolling elements are loaded balancing the distance passed by the rolling elements takes place due to a slip of the rolling element against the race. In order to provide the slip, the forces of ball impact on the separator or adjacent ball must rise to a value exceeding the forces of sliding friction. The more load on the bearing the more sliding friction forces. In such a case, a grease used to lubricate rolling bearings is a necessary element that guarantees correct interaction. Lack of proper lubrication is the main factor leading to bearing wearing. The rolling bearings transferring transverse load only, having baskets of low friction factor materials, may operate without lubrication. International patent application W02011105919 discloses a bearing consisting of two rings equipped with races on which loaded rolling elements move, wherein one race includes at least one groove or indent located transversely to the rolling elements movement direction. Transversal groove or indent allow the rolling element to temporarily separate from cooperation with one of the races and move, against the force of separator or adjacent rolling element, due to different diameters of rolling elements and uneven loading of the bearing rolling elements.

In turn, patent application PL233795 discloses a rolling bearing equipped with a separator separating the rolling elements wherein the race, where the rolling elements move, is equipped with at least one groove located at the angle 4.5° to 80° in relation to the rolling elements movement direction. Skew location of the groove comparing to the transverse groove significantly reduces the forces in the race affecting the rolling element.

Bearings with grooves, especially transverse or with cuts or indents in the race are also disclosed in the following patent applications: EP375938, US20080285903, US1334027, JPH07197937. The known bearings with grooves may operate without lubrication.

Bearing according to PL233795 is equipped with a separator wherein holes for the rolling elements are made at an angle. Forces present between the rolling elements and the separator with skew hole surfaces for the rolling elements reduce the forces in the separator affecting the bearing ring guiding the separator significantly reducing the moment of bearing movement resistance. Skew hole surfaces in the separator are made at specified angle that depends on the value of sliding friction factors of the material the rolling elements are made of and the separator material. In turn, direction of the skews depends on the rotation direction of the bearing. In case of bearings rotating to one specified direction, the skews on the rolling element connection surfaces with the separator are parallel and in case of bearings rotating to both direction, the skews are convergent. Bearing with the separator with skew hole surface is not versatile and must be designed considering material features and direction of rotation.

The objective of the invention is to solve the drawbacks.

Rolling bearing consisting of two rings, external and internal, rolling elements in the form of balls and separator with holes for the rolling element wherein at least one ring race, where the rolling elements move, is equipped with at least one groove, characterized by the fact that the separator has circumferential recess, however in case when the separator is guided along the external ring of the bearing, the circumferential recess is located on the external side of the separator, and the depth of the recess is that the point of contact of the separator with the rolling element is below the diameter passing through the centres of the rolling elements, and in case when the separator is guided along the internal ring of the bearing, the circumferential recess is located on the internal side of the separator, and the depth is so that the point of contact of the separator with the rolling element is located above the diameter passing through the centre of the rolling elements and the groove is located at the angle between 10 and 90° in relation to the direction of the rolling elements movement.

Holes in the separator for rolling elements may be made as parallel or skewed to the axis connecting centre of the ball with the bearing centre.

Preferably, one of the bearing races is in a shape of a spherical bowl section of radius based on the bearing axis.

In case of the separator guided on the internal ring, the separator connects with the ball above the diameter connecting the ball centres due to cutting out a part of the material below this diameter. In case of the separator guided on the external ring, the separator connects with the ball below the diameter connecting the ball centres due to cutting out a part of the material above this diameter. The separator with circumferential recess according to the invention always provides favourable point of interaction with the ball that results in reduction of impact force of the balls on the separator. Based on distribution of force Fn of impact of the separator on the ball at the moment of contact of the bearing ring with the separator it results that the separator is lifted and guided on the balls, because force FK is greater than friction force F _t .

Bearing according to the invention operates correctly during rotation to both directions and the parameters of the circumferential recess are not related to the type of material of the rolling elements and the separator.

Bearing according to the invention has the option to work without lubrication maintaining durability comparable with bearings lubricated with oil, liquid grease or solid grease. Bearing arrangements using two rolling bearings according to the invention operate continuously for over 25 thousand hours and made 6 500 million revolutions under longitudinal load 50 N. At the moment, durability of known non- lubricated bearings loaded with longitudinal force is only a few million revolutions and of those lubricated with solid greases of type Pb, M0S2, with longitudinal load exceeding 50 N does not exceed 60 million revolutions.

The structural solutions according to the invention provide significant results in regular ball bearings, angular bearings, magneto bearings, ball bearings for spindles loaded with longitudinal and transverse force.

The subject of the invention is shown in the drawing, where Fig. 1 presents cross-section of regular ball bearing; Fig. 2 presents a cross-section of a part of regular ball bearing with rotating internal ring with separator guided on the internal ring, Fig. 2a and Fig. 2b present cross-sections A-A and B-B respectively, Fig. 2c presents a view of the separator with recess on its internal part, Fig. 3 presents a cross-section of a part of regular ball bearing with rotating external ring with separator guided on the external ring, Fig. 3a and Fig. 3b present cross-sections A-A and B-B respectively, Fig. 3c presents a view of the separator with recess on its external part, Fig. 4 presents a cross-section of regular ball bearing with skew recess located to the right (Fig. 4a) and to the left (Fig. 4b), Fig. 5 presents a cross-section of regular ball bearing wherein one of the races is in the shape of a section of spherical bowl of radius based on the bearing axis.

Bearing according to the invention in the embodiment shown in Fig. 2, Fig. 2a, Fig. 2b and Fig. 2c is a single-row ball bearing with internal ring 2 rotating in it. The bearing consists of the external ring 1 , internal ring 2, rolling elements in the form of balls 3 and separator 4. The rolling elements 3 roll along the race of the external ring 1 and race of the internal ring 2. The separator 4 is guided on the internal ring 2. Point of contact of the separator 4 with the internal ring 2 is denoted with 9. Point of contact of the rolling element 3 with the race of the external ring 1 is denoted with 5. Point of contact of the rolling element 3 with the race of the internal ring 2 is denoted with 6. The separator 4 may contact the rolling elements 3 along the side walls and above the diameter 8 running through the centre of these elements 3.

Bearing according to the invention in the embodiment shown in Fig. 3, Fig. 3a, Fig. 3b and Fig. 3c is a single-row ball bearing with external ring 2 rotating in it. The bearing consists of the external ring 1 , internal ring 2, rolling elements in the form of balls 3 and separator 4. The rolling elements 3 roll along the race of the external ring 1 and race of the internal ring 2. Point of contact of the separator 4 with the internal ring 1 is denoted with 9. Point of contact of the rolling element 3 with the race of the external ring 1 is denoted with 5. Point of contact of the rolling element 3 with the race of the internal ring 2 is denoted with 6. The separator 4 may contact the rolling elements 3 along the side walls and above the diameter 8 running through the centre of these elements 3.

The race 5 of the external ring 1 has a groove 10 located at the angle a to the motion direction of the rolling elements 3. In Fig. 4a and 4b the groove is located to the right and left at the angle a = 25°.

Bearing according to the invention shown in Fig. 5 has the race is in a shape of a spherical bowl section of radius based on the bearing axis.