JP2024036786A - conductive bearing - Google Patents

Abstract

To provide a conductive bearing capable of ensuring stable conductive performance during high-speed rotation of the bearing to prevent electrolytic corrosion.SOLUTION: A bearing 100 according to the present invention is a conductive bearing, comprising an outer ring 104, an inner ring 108, a ball 110 that rolls between the outer ring and the inner ring, and a conductive ring 112 that electrically conducts between the outer ring and the inner ring. The conductive ring has a fixed part 114 fixed to one of the outer ring and the inner ring, a lip 116 that contacts the other of the outer ring and the inner ring, and a wall part 118 connecting the fixed part and the lip. The lip is formed in a comb-like shape that is intermittent in a circumferential direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a conductive bearing having electrical conductivity.

BACKGROUND ART In recent years, with the progress in the development of EV cars (electric cars), HV cars (hybrid cars), etc., the number of high-voltage parts installed in a single car is increasing. When the current from this high-voltage component passes through the bearing, electrolytic corrosion occurs on the surfaces of the bearing's rolling elements and on the raceway surfaces of the outer ring and inner ring, contributing to damage. Furthermore, as the number of high-voltage components increases, electromagnetic interference between the components also increases. When electromagnetic interference propagates to electronic devices such as computers, navigation devices, communication devices, and in-vehicle radios, it can adversely affect the operation of the devices as electromagnetic noise. Therefore, there is a need for countermeasures against electromagnetic noise in automobiles.

A method taken as a countermeasure against electromagnetic noise is to ground the stray current generated by electromagnetic interference to the surrounding case, and bearings are often used in the path. Electromagnetic noise with a small amount of electricity can often be resolved by keeping the bearing energized at all times, but when the amount of electricity is large, if the energization condition is not good, charges will accumulate, and once they reach a certain level, they will accumulate. Charges may be released all at once. If this occurs at the contact surface between the bearing raceway surface and the ball, which is a path for electric charges, electrolytic corrosion occurs on the contact surface, and a portion of the surface layer melts, resulting in a soft altered layer. If electrolytic corrosion occurs, the bearing must be replaced.

The countermeasure against both electromagnetic noise and electrolytic corrosion is to create a bearing structure that allows current to flow continuously over time without accumulating electric charge. For example, Patent Document 1 discloses an energized rolling bearing as a bearing that can be energized. This current-carrying rolling bearing is equipped with a conductive seal ring mainly for the purpose of preventing electrolytic corrosion of the rolling elements. The seal ring is a component that prevents lubricating oil from leaking and foreign matter from entering, and conductive lubricant is sealed in the tip of the seal lip to improve conductivity.

Japanese Patent Application Publication No. 2009-264401

In the current-carrying rolling bearing of Patent Document 1, although the impedance of the conductive seal ring itself is low, the lubricating oil contained in the bearing forms an oil film between the seal lip and the inner or outer ring when the bearing rotates at high speed. . For this reason, in the current-carrying rolling bearing of Patent Document 1, impedance increases due to the oil film formed when the bearing rotates at high speed, and the electrical conductivity of the seal lip decreases, causing the surface of the rolling elements and the raceway surfaces of the outer ring and inner ring to increase. Electrolytic corrosion may occur.

SUMMARY OF THE INVENTION In view of these problems, an object of the present invention is to provide a conductive bearing that can ensure stable conductive performance during high-speed rotation of the bearing and prevent electrolytic corrosion.

In order to solve the above problems, a typical configuration of the conductive bearing according to the present invention includes an outer ring, an inner ring, rolling elements that roll between the outer ring and the inner ring, and electrical connection between the outer ring and the inner ring. The conductive ring has a fixed part fixed to one of the outer ring or the inner ring, a lip that contacts the other of the outer ring or the inner ring, and a wall part that connects the fixed part and the lip. The lip is characterized in that it is formed in a comb-like shape that is intermittent in the circumferential direction.

In the above configuration, the lip of the conductive ring is formed in a comb shape discontinuous in the circumferential direction and contacts the outer ring or the inner ring. Therefore, even if an oil film is formed during high-speed rotation of the bearing, the comb-like lip can continue to push through the oil film and push it away. Therefore, according to the above configuration, the electrical conductivity due to the lip does not decrease when the bearing rotates at high speed, ensuring stable electrical conductivity and preventing electrolytic corrosion from occurring on the surface of the rolling elements and the raceway surfaces of the outer ring and inner ring. It can be prevented.

According to the present invention, it is possible to provide a conductive bearing that can ensure stable conductive performance and prevent electrolytic corrosion during high-speed rotation of the bearing.

FIG. 1 is an exploded perspective view illustrating a conductive bearing in an embodiment of the present invention. FIG. 2 is a diagram showing main parts of the bearing shown in FIG. 1; 3 is a diagram illustrating the behavior of a conductive ring during high-speed rotation of the bearing in FIG. 2. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements with substantially the same functions and configurations are given the same reference numerals to omit redundant explanation, and elements not directly related to the present invention are omitted from illustration. do.

FIG. 1 is an exploded perspective view illustrating a conductive bearing (hereinafter referred to as bearing 100) in an embodiment of the present invention. In the figure, a portion of the bearing 100 is cut away to show the internal structure. FIG. 2 is a diagram showing essential parts of the bearing 100 of FIG. 1. FIG. 2(a) is a side view of the bearing 100. 2(b) is a sectional view taken along line AA in FIG. 2(a), and FIG. 2(c) is a partially enlarged view of the lip 116.

As shown in FIG. 1, the bearing 100 includes an outer ring 104 having a raceway surface 102 on its inner periphery, an inner ring 108 having a raceway surface 106 on its outer periphery, balls 110 as rolling elements, and a conductive ring 112. The balls 110 are disposed between the outer ring 104 and the inner ring 108 while being held in a cage (not shown), and roll between the raceway surface 102 of the outer ring 104 and the raceway surface 106 of the inner ring 108. .

The conductive ring 112 is a member having electrical conductivity as a whole, and is disposed between the outer ring 104 and the inner ring 108 as shown in FIGS. 2(a) and 2(b). electrically conductive between the two. The conductive ring 112 has a fixing portion 114, a lip 116, a wall portion 118, and a core bar 120, as shown in FIG.

As shown in FIG. 2B, the fixing portion 114 of the conductive ring 112 is fixed to an outer ring stepped portion 122 (see FIG. 1) formed on the inner periphery of the outer ring 104, together with a core bar 120, by, for example, press fitting. Further, the core metal 120 is bent toward the lip 116 and extends along the wall portion 118. The wall portion 118 is made of a conductive resin molded with a core metal 120, and connects the fixing portion 114 and the lip 116.

The lip 116 is made of conductive resin, and is in contact with an inner ring shoulder 124 (see FIG. 1) formed on the outer periphery of the inner ring 108, as shown in FIG. 2(b). Further, as shown in FIGS. 1 and 2(a), the lip 116 is formed in a comb-teeth shape that is discontinuous in the circumferential direction. Therefore, a gap 126 is formed between adjacent lips 116. As shown in FIG. 2(c), each comb tooth of the lip 116 has a tip 116a shaped like an arrowhead so as to be easily bent, and has a narrow shaft portion 116b at the base of the tip 116a. ing.

Note that although the conductive ring 112 is fixed to the outer ring stepped portion 122 of the outer ring 104 by the fixing portion 114, and the lip 116 is in contact with the inner ring shoulder portion 124 of the inner ring 108, a gap 126 is formed between the lips 116. Therefore, it does not have the function of a seal.

In the bearing 100, oil (lubricating oil) exists between the raceway surface 102 of the outer ring 104 and the raceway surface 106 of the inner ring 108, on which the balls 110 roll. Therefore, when the bearing 100 rotates at high speed and the pressure of the lubricating oil increases, it is assumed that the lubricating oil will infiltrate between the lip 116 of the conductive ring 112 and the inner ring shoulder 124 of the inner ring 108. In such a case, an oil film is formed between the lip 116 of the conductive ring 112 and the inner ring shoulder 124 of the inner ring 108, resulting in low electrical conductivity.

Therefore, in the bearing 100, the lip 116 of the conductive ring 112 is formed in the shape of intermittent comb teeth in the circumferential direction to prevent the conductivity from decreasing during high speed rotation. This will be explained in detail below.

FIG. 3 is a diagram illustrating the behavior of the conductive ring 112 when the bearing 100 of FIG. 2 rotates at high speed. Consider a case where the inner ring 108 of the conductive ring 112 rotates in the direction of arrow B in the figure. At this time, the lip tip end surface 128 of the lip 116 formed in a comb tooth shape is in contact with the inner ring shoulder portion 124 of the inner ring 108 . That is, the lip end surface 128 of the lip 116 becomes a contact surface with the inner ring shoulder 124 of the inner ring 108.

Therefore, in the bearing 100, even if an oil film is formed between the lip 116 of the conductive ring 112 and the inner ring shoulder 124 of the inner ring 108 during high-speed rotation, the lip 116 formed in a comb-like shape The tip surface 128 can continue to push through the oil film and push it away as shown by line C in the figure. Note that line C schematically shows the flow of oil displaced by lip 116.

Therefore, according to the bearing 100, the conductivity due to the lip 116 does not decrease during high-speed rotation, and stable conductivity is ensured, and the surface of the balls 110, which are rolling elements, the raceway surface 102 of the outer ring 104, and the inner ring 108. Electrolytic corrosion can be prevented from occurring on the raceway surface 106.

In the conductive ring 112, the fixed part 114 is fixed to the outer ring stepped part 122 of the outer ring 104, and the lip 116 is in contact with the inner ring shoulder part 124 of the inner ring 108. However, the present invention is not limited to this. 108, and the lip 116 may be in contact with the outer ring 104. In this way, even if an oil film is formed between the lip 116 and the outer ring 104 during high-speed rotation of the bearing 100, the lip 116 will push away the oil film, thereby preventing a decrease in conductivity and providing stability. It is possible to ensure good conductivity and prevent electrolytic corrosion. Further, the number and spacing of the comb teeth of the lip 116 are not limited to the illustrated example, and can be determined as appropriate.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can come up with various changes and modifications within the scope of the claims, and these naturally fall within the technical scope of the present invention. Understood.

INDUSTRIAL APPLICATION This invention can be utilized as an electroconductive bearing which has electroconductivity.

DESCRIPTION OF SYMBOLS 100... Bearing, 102... Raceway surface of outer ring, 104... Outer ring, 106... Raceway surface of inner ring, 108... Inner ring, 110... Ball, 112... Conductive ring, 114... Fixing part, 116... Lip, 116a... Tip part, 116b ...Shaft part, 118...Wall part, 120...Core metal, 122...Outer ring step part, 124...Inner ring shoulder part, 126...Gap between lips, 128...Lip end surface

Claims (1)

outer ring and
Inner circle and
a rolling element rolling between the outer ring and the inner ring;
comprising a conductive ring that electrically conducts between the outer ring and the inner ring,
The conductive ring is
a fixing part fixed to one of the outer ring or the inner ring;
a lip that contacts the other of the outer ring or the inner ring;
a wall portion connecting the fixing portion and the lip;
The conductive bearing is characterized in that the lip is formed in a comb-like shape that is intermittent in the circumferential direction.

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