WO2008018765A1

WO2008018765A1 - Seal integrated with encoder for bearing

Info

Publication number: WO2008018765A1
Application number: PCT/KR2007/003832
Authority: WO
Inventors: Jong Soon Im; Ji Hun Park; Min Chul Park; Young Tae Kim
Original assignee: Il Jin Global Co., Ltd.
Priority date: 2006-08-09
Filing date: 2007-08-09
Publication date: 2008-02-14
Also published as: KR100799647B1

Abstract

Disclosed is an encoder-integrated seal 140 mounted on a bearing including a rotary ring, a stationary ring, and a plurality of rolling elements disposed between the rotary ring and the stationary ring, to be located in an opening formed between the rotary ring and the stationary ring to face the rolling elements. The seal 140 includes: a seal support 141 having a first cylindrical portion 141a inserted into the stationary ring; a slinger 147 having a second cylindrical portion 147a inserted into the rotary ring and a radial portion 147b extending from the second cylindrical portion 147a in the radial direction; an elastic part 143 attached to the seal support 141 or the slinger 147; one or more one seal lips 135a, 135b and/or 135c extending from the elastic part 143 and contacting one side of the slinger 147 or the seal support 141; an encoder 140 provided at the radial portion 147b of the slinger 147; and at least one protrusion 150 projected in the radial direction of the slinger 147 toward the first cylindrical portion 141a of the seal support 141. The protrusion 150 rotates along with the bearing 100 to generate a turbulent flow, thereby preventing adhesion of impurities to the seal. Also, a flow is generated in a direction away from the seal lips by the protrusion to block infiltration of impurities through the seal 140.

Description

Description SEAL INTEGRATED WITH ENCODER FOR BEARING

Technical Field

[1] The present invention generally relates to an encoder-integrated seal for bearings, and more particularly to an encoder-integrated seal for bearings that includes a protrusion and/or an assistant protrusion to generate a flow during rotation, thereby efficiently preventing infiltration of impurities into an opening of a bearing. Background Art

[2] A bearing, which is mounted on car suspensions, serves to rotatably support car wheels. Recently, the bearing is provided with a component for detecting rotation of the wheels so as to detect the wheel rotation in addition to the rotational support of the wheels. That is, the bearing is designed to have a device for measuring the rotational speed of the wheels to control an anti-lock braking system (ABS) or a traction control system (TCS).

[3] Fig. 1 is a cross-sectional view of a hub bearing including a device for detecting a rotational speed of a car wheel. Fig. 2 is an enlarged cross-sectional view of Part "A" of Fig. 1. Referring to Figs. 1 and 2, the bearing 1 having the device for detecting the rotational speed the wheel includes: an outer ring 20 having at least one outer ring race 21; an inner ring 10 having at least one inner ring race 11; a plurality of rolling elements 30 disposed between the inner ring race 11 and the outer ring race 21; and a seal 40 sealing an opening, which is defined between the inner ring 10 and the outer ring 20 to face the rolling elements 30.

[4] A spline is located on an inner periphery 63 of a hub 60 and a seat 67 is formed at one side of an outer periphery thereof. The hub 60 includes a flange 65 having at least one hole 65a, into which a securing bolt 70 is inserted. A car wheel (not shown) is mounted on the securing bolt 70. In Fig. 1, a single inner ring 10 is mounted on the seat 67. However, the seat 67 may extend to the flange 65 such that a pair of inner rings 10 can be mounted thereon.

[5] A knuckle flange 25 is formed on an outer periphery of the outer ring 20 to fix a knuckle joint (not shown) such that the knuckle joint can be connected to a suspension. A molding part 61 is formed to maintain the inner ring 10 on the seat 67 of the hub 60 and to apply preload to the bearing. A seal 80 is formed between the outer ring 20 and the hub 60 to seal the opening therebetween.

[6] As shown in Fig. 2, a seal 40 located in the opening formed between the inner ring

10 and the outer ring 20 includes: a seal support 41 mounted on an inner periphery 23 of the outer ring 20; a slinger 47 mounted on an outer periphery 13 of the inner ring 10; an elastic part 43 attached to the seal support 41 toward the slinger 47; an encoder 49 mounted on an outer side of the slinger 47; and a plurality of seal lips 35a, 35b and 35c extending from the elastic part 43 and contacting an opposite side of the slinger 47 to the encoder 39. In Fig. 2, a dotted line indicates a sensor for detecting rotation of the bearing in association with the encoder 49.

[7] As shown in Fig. 2, with an increasing demand of a compact seal, the encoder- integrated seal 40 formed by integrating the seal to the encoder 49 has been spotlighted. In a conventional encoder-integrated seal 40, however, impurities are likely to infiltrate into a gap formed between the seal support 41 and the outer periphery of the slinger 47 or the gap formed between the slinger 47 and the outer periphery 13 of the inner ring 10, thereby causing reduction in lifetime of the bearing. The seal 40 may have an additional seal lip (not shown) extending from the encoder 49 and contacting the outer periphery 13 of the inner ring 10 to block the impurities from entering the gap formed between the slinger 47 and the outer periphery 13 of the inner ring 10. However, the additional seal lip is brought into contact with the outer periphery 13 of the inner ring 10 and increases frictional resistance. Moreover, a contact portion of the seal lip is likely to be worn out due to a long time use, thereby deteriorating the function of preventing infiltration of impurities. Disclosure of Invention Technical Problem

[8] The present invention relates to solving the foregoing problems of the prior art, An aspect of the present invention is to provide an encoder- integrated seal for bearings that includes a protrusion and/or an assistant protrusion to form a flow by rotating along with the bearing, thereby preventing infiltration of impurities into the bearing.

[9] It is another aspectof the invention to provide an encoder- integrated seal for bearings that operates without contacting the other components so that the seal is not damaged or worn out even after a long time use, thereby efficiently preventing deterioration in impurity infiltration effect and an increase of frictional resistance. Technical Solution

[10] According to an aspect of the invention, there is provided an encoder- integrated seal mounted on a bearing comprising a rotary ring, a stationary ring, and a plurality of rolling elements disposed between the rotary ring and the stationary ring to be located in an opening formed between the rotary ring and the stationary ring to face the rolling elements, including: a seal support having a first cylindrical portion inserted into the stationary ring; a slinger having a second cylindrical portion inserted into the rotary ring and a radial portion extending from the second cylindrical portion in the radial direction; an elastic part attached to the seal support or the slinger; at least one seal lip extending from the elastic part and contacting one side of the slinger or the seal support; an encoder provided at one side of the radial portion of the slinger; and at least one protrusion projected from the encoder toward the first cylindrical portion of the seal support in a radial direction of the slinger. Preferably, the protrusion is integrated with the encoder.

[11] The protrusion may have a circumferentially decreasing width and a radially decreasing height with an increase in distance from the rolling elements in an axial direction. Further, the elastic part of the seal may be attached to a portion of the first cylindrical portion or to the entire first cylindrical portion.

[12] The elastic part may be attached to a portion of the first cylindrical portion of the seal support or the entire first cylindrical portion. Also, the slinger may further include a third cylindrical portion separated from the second cylindrical portion and extending from the radial portion. The seal may further include at least one mud lip extending from the elastic part attached to the first cylindrical portion and contacting the third cylindrical portion. Further, the protrusion may have a radially decreasing height toward the rolling elements.

[13] The protrusion may have a circumferentially increasing width toward the rolling elements.

[14] The elastic part may have a radially increasing thickness toward the rolling elements.

[15] The protrusion may further include a portion having a radially increasing height toward the rolling elements.

[16] The seal may include at least one assistant protrusion formed opposite to the protrusion in the radial direction of the slinger and having a predetermined height and width, wherein the assistant protrusion may have a circumferentially decreasing width and a radially decreasing height with an increase in distance from the rolling elements in the axial direction.

Advantageous Effects

[17] According to the present invention, when a bearing having an encoder- integrated seal is mounted and rotates in a vehicle and the like, a protrusion formed in the radial direction of a slinger and having a predetermined height and width toward a first cylindrical portion of a seal support rotates at the same time. As a result, a turbulent flow is generated by the rotation of the protrusion to prevent adhesion of impurities to the seal and to block infiltration of impurities into the seal.

[18] In addition, when the seal includes a third cylindrical portion on the slinger and a mud lip contacting the third cylindrical portion, the protrusion provides more enhanced effects of blocking impurities. [19] Moreover, the seal includes at least one assistant protrusion formed in the radial direction on the slinger opposite to the protrusion and having a predetermined height and width, thereby effectively preventing infiltration of impurities through a gap between a second cylindrical portion of the slinger and a rotary ring.

[20] Moreover, the protrusion and the assistant protrusion rotate without any contact, thereby preventing frictional resistance while blocking infiltration of impurities. Brief Description of the Drawings

[21] Fig. 1 is a cross-sectional view of a conventional wheel bearing;

[22] Fig. 2 is an enlarged cross-sectional view of part "A"in Fig. 1;

[23] Fig. 3 is a partially cross-sectional view of an encoder-integrated seal for a bearing according to a first embodiment of the present invention;

[24] Fig. 4 is an enlarged cross-sectional view of the encoder- integrated seal of Fig. 3;

[25] Fig. 5 is a partially perspective view of the encoder-integrated seal of Fig. 4;

[26] Fig. 6 is a partially perspective view of a protrusion of the encoder-integrated seal of Fig. 4;

[27] Fig. 7 is a cross-sectional view taken along line A-A of Fig. 6;

[28] Fig. 8 is a plan view of the protrusion of Fig. 6;

[29] Fig. 9 is a cross-sectional view of one modification of the encoder- integrated seal of

Fig. 4;

[30] Fig. 10 is a cross-sectional view of another modification of the encoder-integrated seal of Fig. 4;

[31] Fig. 11 is a cross-sectional view of an encoder-integrated seal according to a second embodiment of the present invention;

[32] Figs. 12 to 17 are cross-sectional views of other modifications of the encoder- integrated seal of Fig. 10; and

[33] Fig. 18 is a partially cross-sectional view of an encoder-integrated seal for a bearing including a rotary outer ring. Best Mode for Carrying Out the Invention

[34] Exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In description of an encoder-integrated seal according to the present invention, like terms as those of a conventional technique will be used to designate like components. Thus, repetitious descriptions will be omitted.

[35] Fig. 3 is a partially cross-sectional view of an encoder-integrated seal for a bearing according to a first embodiment of the present invention. Fig. 4 is an enlarged cross- sectional view of the encoder-integrated seal of Fig. 3. Fig. 5 is a partially perspective view of the encoder-integrated seal of Fig. 4. Fig. 6 is a partially perspective view of a protrusion of the encoder-integrated seal of Fig. 4. Fig. 7 is a cross-sectional view taken along line A-A of Fig. 6. Fig. 8 is a plan view of the protrusion of Fig. 6.

[36] In this embodiment, the bearing 100 is used in a car wheel or the like and includes a rotary inner ring 110 and a stationary outer ring 120. Generally, the wheel bearing 100 for the car includes two inner ring races 111, two outer ring races 121, and rolling elements disposed in a plurality of rows on the inner ring races 111 and the outer ring races 121. In addition, the rotary inner ring 110 may include a flange on which a car wheel (not shown) will be mounted.

[37] Referring to Fig. 3, an encoder- integrated seal according to the first embodiment is mounted on the bearing 100 that includes the inner ring 110 and the outer ring 120. The inner ring 110 is a rotary ring and the outer ring 120 is a stationary ring. The inner ring 110 is formed with the inner ring race 111, the outer ring 120 is formed with the outer ring race 121, and the plurality of rolling elements 130 are disposed between the inner and outer rings. The encoder-integrated seal 140 is located in an opening, which is formed between the inner ring 110 and the outer ring 120 to face the bearing 100.

[38] Referring to Figs. 3 to 6, according to the first embodiment of the present invention, the seal 140 includes: a seal support 141 inserted into an inner periphery 123 of the outer ring 120; an elastic part 143 attached to the seal support 141; a slinger 147 inserted into an outer periphery 113 of the inner ring 110; an encoder 149 provided at one side of the slinger 147; and one or more seal lips 135a, 135b and/or 135c extending from the elastic part 143 and contacting the slinger 147.

[39] The seal support 141 includes a first cylindrical portion 141a inserted into the inner periphery 123 of the outer ring 120 and contacting the inner periphery 123, as well as a ring-shaped portion 141b extending from the first cylindrical portion 141a in the radial direction.

[40] The elastic part 143 attached to the seal support 141 is preferably formed of elastomer and may be attached only to the ring-shaped portion 141b. Alternatively, the elastic part 143 may be attached to a partial or the overall surface of the ring-shaped portion 141b and first cylindrical portion 141a, as shown in Figs. 3 and 4.

[41] The slinger 147 includes a second cylindrical portion 147a inserted into the outer periphery 113 of the inner ring 110 and contacting the outer periphery 113. It also includes a radial portion 147b extending from the second cylindrical portion 147a in the radial direction.

[42] The slinger 147 rotates along with the inner ring 110 when the inner ring 110 inserted into the outer periphery 113 rotates. The slinger 140 is provided at one side with the encoder 149. The encoder 149 includes permanent magnets, of which N-poles and S -poles are alternately located at predetermined intervals in a circumferential direction.

[43] The seal 140 includes at least one protrusion 150 projected toward the first cylindrical portion 141a of the seal support 141 in the radial direction of the slinger 147. The protrusion 150 may be formed integrally with the encoder 149 to possess magnetic properties of the N-pole or the S -pole. The protrusion 150 may be formed of nonmagnetic material and be attached to the encoder 149 and/or the slinger 147. Mode for the Invention

[44] Referring to Figs. 5 to 8, the protrusion 150 preferably has a decreasing width and height with an increase in distance from the rolling elements 130 in a direction of a rotational axis. As shown in Fig. 6, the protrusion 150 may have a trapezoidal cross- section. As shown in Figs. 4, 9 and 10, the protrusion 150 may have a lateral side 153 of a trapezoidal, triangular or two-triangular shape.

[45] As such, the protrusion 150 has slanted upper and lateral sides 151 and 153, and a turbulent flow is generated by the protrusion 150 when the inner ring 110 rotates. Then, incoming fluid contacts the slanted upper and lateral sides 151 and 153, and flows in a direction away from the seal lips 135a, 135b and/or 135c (to the right side and upward in Fig. 3). Accordingly, adhesion or infiltration of impurities into the bearing 100 through the seal 140 can be effectively blocked.

[46] Fig. 11 is a cross-sectional view of an encoder-integrated seal according to a second embodiment of the present invention. Figs. 12 to 17 are cross-sectional views of other modifications of the encoder-integrated seal of Fig. 10.

[47] As shown in Fig. 11, an encoder- integrated seal 140 according to this embodiment includes: a seal support 141 disposed in the opening of the outer ring 120 and having a first cylindrical portion 141a and a ring-shaped portion 141b extending from the first cylindrical portion 141a in the radial direction; an elastic part 143 attached to the seal support 141 ; a slinger 147 disposed in the opening of the inner ring 110 and having a second cylindrical portion 147a, a radial portion 147b extending from the second cylindrical portion 147a in the radial direction, and a third cylindrical portion 147c extending from an end of the radial portion 147b in the axial direction; an encoder 149 provided at one side of the slinger 147; one or more seal lips 135a, 135b and/or 135c extending from the elastic part 143 and contacting the slinger 147; and at least one protrusion 150 projected toward the first cylindrical portion 141a of the seal support 141 in the radial direction of the slinger 147.

[48] In addition, the seal 140 further includes a mud lip 135d extending from the elastic part 143 and contacting the third cylindrical portion 147c of the slinger 147.

[49] The protrusion 150 may have a radially increasing or decreasing height with an increase in distance from the mud lip 135d. In the second embodiment, the protrusion 150 has the radially increasing height with an increase in distance from the mud lip 135d. In such a case, when the protrusion 150 rotates integrally with the bearing 100, impurities interposed between the protrusion 150 and the mud lip 135d can be efficiently removed. When the protrusion 150 has a circumferentially decreasing width with an increase in distance from the mud lip 135d, the aforementioned effects can be further enhanced.

[50] When it has the radially increasing height with an increase in distance from the mud lip 135d, the protrusion 150 may have a lateral side of a triangular, trapezoidal or two- triangular shape as shown in Figs. 11 to 13.

[51] The elastic part 143 attached to the first cylindrical portion 141a of the seal support

141 may have a radially constant thickness as shown in Figs. 11 to 13. Alternatively, the elastic part 143 may have a decreasing thickness with an increase in distance from the mud lip 135d as shown in Figs. 14 to 16.

[52] Further, the thickness of the elastic part 143 and the height of the protrusion 150 may be radially constant regardless of the distance from the mud lip 135d as shown in Fig. 17.

[53] In the first and second embodiments of the present invention, the encoder-integrated seal 40 is mounted on the opening formed between the rotary inner ring 110 and the stationary outer ring 120 of the bearing 100. It should be noted, however, that the present invention is not limited to the aforementioned embodiments.

[54] Fig. 18 is a cross-sectional view of an encoder-integrated seal 140, which is mounted in an opening between a rotary outer ring and a stationary inner ring of a bearing. Referring to Fig. 18, the encoder- integrated seal 140 for bearings according to the present invention includes: a seal support 141 inserted into an outer periphery 113 of the inner ring 110; an elastic part 143 attached to the seal support 141; a slinger 147 inserted into an inner periphery 123 of the outer ring 120; an encoder 149 provided at one side of the slinger 147; and one or more seal lips 135a, 135b and/or 135c extending from the elastic part 143 and contacting the slinger 147.

[55] The seal support 141 includes a first cylindrical portion 141a inserted into the outer periphery 113 of the inner ring 110 to contact the outer periphery 113, and a ring- shaped portion 141b extending from the first cylindrical portion 141a in the radial direction.

[56] The slinger 147 includes a second cylindrical portion 147a inserted into the inner periphery 123 of the outer ring 120 to contact the inner periphery 123, and a radial portion 147b extending from the second cylindrical portion 147a in the radial direction.

[57] In the above description, the bearing 100 is illustrated as having the inner ring 110 or the outer ring 120. However, it should be noted that the inner ring 110 and the outer ring 120 may be expressed as a stationary ring or a rotary ring when the bearing 100 is mounted and operates. In such a case, the encoder-integrated seal 140 is mounted on the bearing 100, which includes a rotary ring, a stationary ring and a plurality of rolling elements disposed between the rotary ring and the stationary ring, and is disposed in an opening formed between the rotary ring and the stationary ring. Here, the seal 140 includes: a seal support 141 having a first cylindrical portion 141a inserted into the stationary ring; an elastic part 143 attached to the seal support 141; a slinger 147 having a second cylindrical portion 147 a inserted into the rotary ring and a radial portion 147b extending from the second cylindrical portion 147a in the radial direction; one or more seal lips 135a, 135b and/or 135c extending from the elastic part 143 and contacting one side of the slinger 147; an encoder 149 provided at one side of the radial portion 147b of the slinger 147; and at least one protrusion 150 projected toward the first cylindrical portion 141a of the seal support 141 in the radial direction of the slinger 147.

[58] When the encoder-integrated seal 140 is mounted on the bearing 100, the second cylindrical portion 147a of the slinger 147 is brought into contact with the outer periphery 113 of the inner ring 110 when the inner ring 110 rotates, or brought into contact with the inner periphery 123 of the outer ring 120 when the outer ring 120 rotates. In order to prevent infiltration of external impurities into a gap between the second cylindrical portion 147a of the slinger 147 and the rotary ring, the seal 140 preferably has at least one assistant protrusion 160 projected opposite the protrusion 150 in the radial direction and having a predetermined height and width.

[59] Preferably, the assistant protrusion 160 has a circumferentially decreasing width and a radially decreasing height with an increase in distance from the rolling elements 130.

[60] With such a height and width, the assistant protrusion 160 rotates along with the bearing 100 to generate a turbulent flow in a direction away from the second cylindrical portion 147a of the slinger 147. Thus, when the assistant protrusion 160 rotates, it is possible to effectively prevent adhesion of impurities to the second cylindrical portion 147a of the slinger 147 and a contact area of the rotary ring, or infiltration of impurities into the bearing 100.

[61] In the above description, the elastic part 143 is attached to the seal support 141, and the seal lips 135a, 135b, 135c and/or 135d extend from the elastic part 143 to contact with the slinger 147. However, the elastic part 143 may be attached to the slinger 147, and the seal lips 135a, 135b, 135c and/or 135d may extend from the elastic part 143 to contact with the seal support 141.

[62] The seal support 141 and the slinger 147 are preferably made of steel or reinforced plastics to have a predetermined level of rigidity. However, it should be noted that the present invention is not limited to these materials.

[63] Although the present invention has been described in connection with the preferred embodiments and the drawings, it should be noted that the present invention is not limited to these embodiments and drawings. It will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

[1] An encoder-integrated seal mounted on a bearing comprising a rotary ring, a stationary ring, and a plurality of rolling elements disposed between the rotary ring and the stationary ring to be located in an opening formed between the rotary ring and the stationary ring to face the rolling elements, including: a seal support having a first cylindrical portion inserted into the stationary ring; a slinger having a second cylindrical portion inserted into the rotary ring and a radial portion extending from the second cylindrical portion in the radial direction; an elastic part attached to the seal support or the slinger; at least one seal lip extending from the elastic part and contacting one side of the slinger or the seal support; an encoder provided at one side of the radial portion of the slinger; and at least one protrusion projected from the encoder toward the first cylindrical portion of the seal support in a radial direction of the slinger.

[2] The seal according to claim 1, wherein the protrusion is integrated with the encoder.

[3] The seal according to claim 1, wherein the protrusion has a circumferentially decreasing width and a radially decreasing height with an increase in distance from the rolling elements.

[4] The seal according to claim 3, wherein the elastic part of the seal is attached to a portion of the first cylindrical portion or to the entire first cylindrical portion.

[5] The seal according to claim 1, wherein the elastic part of the seal is attached to a portion of the first cylindrical portion of the seal support or the entire first cylindrical portion, the slinger further comprises a third cylindrical portion separated from the second cylindrical portion and extending from the radial portion, the seal further comprises at least one mud lip extending from the elastic part attached to the first cylindrical portion and contacting the third cylindrical portion, and the protrusion has a radially decreasing height toward the rolling elements.

[6] The seal according to claim 5, wherein the protrusion has a circumferentially increasing width toward the rolling elements.

[7] The seal according to claim 5, wherein the elastic part has a radially increasing thickness toward the rolling elements.

[8] The seal according to claim 5, wherein the protrusion further comprises a portion having a radially increasing height toward the rolling elements.

[9] The seal according to claim 3, wherein the protrusion further comprises a portion having a radially increasing height toward the rolling elements.

[10] The seal according to any one of claims 1 to 9, further comprising: at least one assistant protrusion formed opposite to the protrusion in the radial direction of the slinger and having a predetermined height and width, wherein the assistant protrusion has a circumferentially decreasing width and a decreasing height with an increase in distance from the rolling elements in the axial direction.