JP2003013976A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve either of two inconveniences of leakage of lubricant and invasion of foreign objects from the outside without increasing contact torque of a seal portion. SOLUTION: A seal member 5 is comprised of a rubber-like elastic body 7 and core metal 6. The seal member 5 is fixed in an outer ring 2 and is opposed to a seal groove 9 of an inner ring 1. The elastic body 7 is provided with a lip supporting portion 7a, an inner lip 11 extending inward, an intermediate lip 12, and an outer lip 13. The inner lip 11 is arranged to keep in contact with a seal groove inner sidewall 9b. The intermediate lip 12 is provided with a parallel pointed end portion 12a approximately parallel to a axial direction of a bearing against a seal groove bottom surface 9a and is also arranged to be in non-contact with the seal groove bottom surface 9a. The outer lip 13 has an opposing portion to an outer peripheral surface of a shoulder portion 1c of outside the bearing rather than a seal groove 9 of an inner ring and is also arranged to keep in non-contact with the outer peripheral surface of the shoulder portion 1c via a gap existed between the outer lip and outer peripheral surface of the shoulder portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing with a seal, for example, a rolling bearing used for general industrial use or automobile idler pulleys, timing belt pulleys and the like.

[0002]

BACKGROUND OF THE INVENTION Rolling bearings with seals are widely used because they contain a lubricant and do not require external lubrication, and many seals have been devised and put into practical use. Has been done. The performance required of the seal is to prevent foreign matter from entering and leakage of the lubricant enclosed in the bearing. Further, in recent years, there has been an increasing demand for low fuel consumption (lower torque), smaller size, and higher performance of bearings. Especially in the seal design,
It is necessary to improve the sealing performance while keeping the contact of the seal lip slight so as not to increase the bearing operating torque. Generally, the higher the hermetic seal, the higher the contact resistance of the seal portion, which causes the problem that the bearing friction torque becomes large.Under severe operating conditions, the development of a seal that satisfies both the hermeticity and the low torque is an issue. Has become.

As one of the conventional techniques, there is JP-A-55-63010. This conventional example is composed of an inner lip, an outer lip, and an intermediate lip. The intermediate lip has a tip divided into two parts, at least one of which comes into contact with the side wall of the seal groove to form an intermediate sealing portion. It has a seal structure. It is composed of four lips in this way, and in various experiments conducted so far, it was confirmed that the greater the number of seal lips, the better the sealing performance, and the purpose of improving the sealing performance was achieved. You can do it. However, since the seal is press-fitted into the seal mounting groove of the outer ring and assembled to the bearing, it is difficult to assemble the seal with high precision such as press-fitting of metals. Also,
The seal mounting groove of the outer ring into which the seal is inserted and the seal groove of the inner ring that rotates relative to the seal often have a turning finish in order to reduce costs, and it is difficult to machine the dimensional accuracy to the order of μm. Depending on the place of use such as an automobile idler pulley, there are cases where the outer ring is used for rotation.In that case, the outer ring is displaced axially by the vibration of the belt, and the seal lip that was statically non-contact It must be taken into consideration that a contact may occur with the inner ring, resulting in an increase in bearing friction loss. As mentioned above, when considering the accuracy of the outer ring seal mounting groove into which the seal is inserted, the accuracy of manufacturing the seal body, the accuracy of the inner ring seal groove, and the axial vibration during operation, the operating torque is kept at a low value and the specified value is maintained. It becomes more difficult to exert the sealing performance as the number of seal lips increases. In the case of this conventional example, dividing the tip of the intermediate lip into two directions is a problem in the case of mass production in which the tightening margin of the contacting lip and the relative distance from the other lip are controlled, which results in low friction loss. It becomes difficult to satisfy both the high sealing property.

As another conventional technique, there is JP-A-59-112028. This prior art is composed of an inner lip, an outer lip, and an intermediate lip.
55-63010), and has a seal structure in which the tip of the intermediate lip is divided into two and at least one contacts the side wall of the seal groove to form an intermediate sealing portion. Similar to the above-mentioned example, this conventional example also has a problem in that the contact with another lip causes an increase in bearing friction loss.

As a device in which the angle at which the seal lip (tongue) contacts the side wall of the seal is changed, there is a technique shown in Japanese Utility Model Laid-Open No. 63-68518, which defines the angle between the upper surface of the tongue and the side wall of the tongue. It is formed to be larger than the angle formed by the lower surface and the side wall. This conventional example is intended to exhibit stable sealing performance against pressure changes inside and outside the bearing and to maintain a light torque.However, a gas vent hole communicating between the inside and outside of the bearing is provided. If this is the case, the technology of this conventional invention is unnecessary. Further, this example is not intended to enhance the prevention of foreign matter intrusion.

As another conventional technique for the three-lip structure, there is a technique shown in Japanese Utility Model Laid-Open No. 2-2526. This is a structure with an outer lip extending axially outward, an inner lip extending axially inward, and an intermediate lip extending radially between the outer lip and the inner lip. By having two constrictions, the followability of the lip is improved. This conventional example has a problem that the contact torque of the seal increases because the inner lip and the outer lip come into contact with the inner ring.

Still another conventional technique of the three-lip structure is the technique disclosed in Japanese Utility Model Laid-Open No. 3-26381. Similar to the above-mentioned conventional example (actual open flat 2-2526), this causes a problem that the torque of the seal increases because the inner lip and the outer lip come into contact with the inner ring.

An object of the present invention is to provide a bearing structure in which a lubricant is hermetically sealed and a seal member is fixed to an inner peripheral portion of an outer ring, without causing increase in contact torque of the seal portion and leakage of the lubricant and external leakage. It is an object of the present invention to provide a rolling bearing capable of improving both of the two performances required of a seal, namely, the entry of foreign matter.

[0009]

In the rolling bearing of the present invention, a seal member is composed of a rubber-like elastic body and a core metal,
In the rolling bearing in which the seal member is fixed to the inner peripheral portion of the outer ring and the seal groove is formed on the outer peripheral surface of the inner ring, the seal groove of the inner ring has a bottom surface formed into a flat surface having a cylindrical surface, and the elastic body is , A lip support portion extending from the inner diameter end of the core metal to the inner diameter side, and on the inner diameter side of the lip support portion, an inner lip that comes into contact with a seal groove inner side wall inside the bearing of the inner ring seal groove, and a groove of the inner ring seal groove An intermediate lip that is arranged in a non-contact manner so as to have a parallel tip portion that is substantially parallel to the bearing axial direction with respect to the bottom surface, and a portion that faces the outer peripheral surface of the shoulder portion outside the bearing than the inner ring seal groove. It is characterized in that three lips are arranged, an outer lip and a non-contact outer lip which are arranged with a gap from the outer peripheral surface of the portion.

According to this structure, since the sealing member is provided with three lips to improve the sealing performance, and only one of the lips is in contact with the sealing member, an increase in the seal contact torque can be prevented. If the number of contacting lips is reduced, the function to prevent the leakage of lubricant and the invasion of foreign matter is deteriorated. Therefore, an intermediate lip and an outer lip are provided, and two or more non-contact seal parts are provided between the inner ring seal groove and the inner ring seal groove. Is provided to improve the sealing performance due to the labyrinth sealing effect.
It is preferable that the non-contacting middle lip and the outer lip are provided so as not to come into contact with each other even when the inner ring and the outer ring of the bearing are relatively displaced in the axial direction due to the existence of the bearing inner clearance. Since the intermediate lip is configured to have a parallel tip end portion that is substantially parallel to the bottom surface of the seal groove, it functions to suppress the flow of the lubricant retained in the bottom portion of the seal groove. With these sealing functions,
The lubricant having a high viscosity is easily retained in the bottom of the seal groove, and the retained lubricant has a role of preventing the intrusion of muddy water from the outside of the bearing.

The seal member may be arranged such that the lip support portion is arranged on the inner diameter side of the core metal in the radial inner diameter side, and the lip support portion is provided with a constricted portion. By disposing the lip support portion on the inner diameter side in the radial direction of the inner diameter end of the core metal, even when the seal member rotates due to outer ring rotation,
It is possible to prevent the inner lip, the middle lip, and the outer lip, which are the lips arranged on the inner diameter side of the lip support portion, from opening due to centrifugal force, increasing the seal contact torque due to excessive contact of the inner lip, and The non-contact with the inner side wall of the seal groove and the reduction of the sealing performance are prevented. Also, by providing a constricted part, the rigidity of the lip support part is reduced, and if the seal contact resistance is the same, a large seal tightening margin at the time of design is secured at the contact part between the inner lip and the inner wall of the seal groove. Therefore, it is possible to reduce the deterioration of the sealing performance when the inner ring and the outer ring are relatively displaced in the axial direction.

The contact angle between the inner lip and the inner wall of the seal groove may be such that the contact angle on the outside of the bearing is smaller than the contact angle on the inside of the bearing. The contact angle on the outer side of the bearing is the angle formed by the surface of the inner lip and the inner wall of the seal groove toward the outer side of the bearing. The contact angle on the inside of the bearing is the angle formed by the surface of the inner lip and the inner wall of the seal groove toward the inside of the bearing. In this way, by making the contact angle on the outside of the bearing smaller than the contact angle on the inside of the bearing, it is possible to effectively retain the grease near the inner lip and effectively prevent foreign matter from entering the inside of the bearing. Therefore, the effect of preventing foreign matter from entering from the outside is further promoted.

As the fourth lip, the above-mentioned elastic body may be provided with a grease lip which forms a non-contact radial gap with the outer peripheral surface of the inner ring inner shoulder portion. By providing the grease lip in this way, the effect of preventing leakage of the lubricant inside the bearing is enhanced, and it is preferable to provide the grease lip depending on the application. This grease lip is provided so that a non-contact radial gap is formed between the inner lip of the inner ring and the outer peripheral surface of the shoulder, and even if the inner ring of the bearing and the seal member are displaced relatively in the axial direction, contact is made. Without increasing the seal contact torque.

The inner lip may be provided with degassing grooves at a plurality of positions along the periphery of the tip, such that gas can pass between the outside of the bearing and the inside of the bearing. Generally, when operating a bearing,
Bearing temperature rises due to internal friction loss of the bearing, loss of lubricant agitation, and seal contact torque. When the pressure inside the bearing is reduced due to the bearing temperature being lowered due to the stop of the bearing operation, a pressure difference with the outside of the bearing may occur, and a sticking phenomenon may occur at the seal contact portion. If a gas vent groove is provided on the inner lip that serves as a contact seal as described above, gas will pass between the outside of the bearing and the inside of the bearing, and the above pressure difference can be eliminated, and the sticking phenomenon of the seal contact portion It can be prevented.

[0015]

1 is a block diagram of a first embodiment of the present invention.
And it demonstrates with FIG. This rolling bearing has an inner ring 1
And a plurality of rolling elements 3 are interposed between the raceways 1a and 2a of the outer ring 2 and a cage 4 for holding these rolling elements 3 is provided,
The seal members 5 are provided on both sides. For example, the rolling elements 3 are balls, and in this case, the bearing is a deep groove ball bearing with a seal. The seal member 5 is composed of a rubber-like elastic body 7 and a core metal 6, and its outer peripheral portion is fixed in a fitted state in a seal mounting groove 8 formed on the inner peripheral surface of the outer ring 2.
The rubber-like elastic body 7 is made of synthetic rubber, and the core metal 6 is made of steel plate. The inner ring 1 has a seal groove 9 formed of a circumferential groove at a position corresponding to the inner diameter of each seal member 5.
The seal mounting groove 8 and the seal groove 9 are finished by turning.

As shown in an enlarged view in FIG. 1B, the bottom surface 9a of the seal groove 9 is formed as a flat surface having a cylindrical surface, and both the seal groove inner side wall 9b and the seal groove outer side wall 9c are inclined. It is regarded as a face. The seal groove inner side wall 9b and the seal groove outer side wall 9c are a bearing inner side wall surface and a bearing outer side wall surface of the seal groove 9, respectively. Inner ring 1 seal groove 9
The outer peripheral surface 1c of the shoulder portion outside the bearing is lower than the outer peripheral surface 1b of the bearing portion inside the bearing than the seal groove 9, that is, formed to have a small diameter. Bottom 9a of seal groove 9 and side walls 9 on both sides
The corners with b and 9c and the corners extending from the seal groove inner side wall 9b to the shoulder outer peripheral surface 1b are all rounded or formed into an arcuate cross-sectional shape.

The elastic body 7 of the seal member 5 has a lip support portion 7a extending from the inner diameter end 6a of the core metal 6 toward the inner diameter side, and the inner lip 11, the intermediate lip 12, and the inner lip 11, on the inner diameter side of the lip support portion 7a. And three lips 11 of the outer lip 13
~ 13 are provided. The inner lip 11 is provided so as to come into contact with the seal groove inner side wall 9b inside the bearing of the inner ring seal groove 9. The intermediate lip 12 has a parallel tip portion 12 that is substantially parallel to the groove bottom surface 9 a of the inner ring seal groove 9 in the bearing axial direction.
a, and is arranged in non-contact with the groove bottom surface 9a. The outer lip 13 has a portion facing the shoulder outer peripheral surface 1c on the outer side of the bearing than the inner ring seal groove 9, and the shoulder outer peripheral surface 1
It is arranged in a non-contact manner with a gap from c. The outer lip 13 has a parallel portion 13a that is substantially parallel to the bearing axial direction with respect to the outer peripheral surface 1c of the inner ring shoulder portion. In the illustrated example, the inner diameter of the outer lip 13 is the parallel portion 13a over the entire area from the base end to the tip. Specifically, the intermediate lip 12 extends from the lip support portion 7a toward the inner diameter side substantially perpendicular to the bearing axis. Inner lip 1
1 projects from the side surface of the intermediate lip 12 to the inside of the bearing.
The outer lip 13 extends from the lip support portion 7a to the intermediate lip 1.
It extends to the outside of the bearing with the portion extending over the root of 2 as the base end.

The inner lip 11 is provided with a gas vent groove 15. The degassing groove 15 has a size such that gas can pass between the inside of the bearing and the outside of the bearing,
The inner lip 11 is provided at a plurality of positions on the peripheral edge of the tip. The depth of the degassing groove 15 may be a depth over substantially the entire protruding height of the inner lip 11.

The operation of the above configuration will be described. In this rolling bearing, in the bearing structure in which the seal member 5 is fixed to the seal mounting groove 8 of the outer ring 2, three lips 11 to 13 are arranged to improve the sealing performance, and a lip that contacts the inner ring 1 is provided. Is always configured in one place. Therefore, it is possible to improve both of the two performances required for the seal, that is, the leakage prevention of the lubricant and the invasion of foreign matter from the outside.

The inner lip 11, which is the first lip, prevents the lubricant from leaking inside the bearing by coming into contact with the inner side wall 9b of the seal groove, and the lubricant existing in the vicinity of the lip contact portion prevents the lubricant from the outside. Prevents foreign matter from entering the bearing. The second lip, the intermediate lip 12, serves as a labyrinth seal and also serves the following purpose. Typically,
The lubricant enclosed in the bearing is grease, and the viscosity coefficient of the grease base oil is about 15 mPas at 80 ° C. Since this is as large as 15 times that of 20 ° C. water, if there is a flow resistance part such as the intermediate lip 12 at the bottom of the seal groove 9, it functions to prevent the lubricant from flowing in the axial direction, and the seal groove is prevented. The lubricant having a large viscosity easily stays at the bottom of the groove 9. The retained lubricant plays a role of preventing the intrusion of muddy water from the outside of the bearing. Usually, the inner ring 1 and the outer ring 2 are assembled with a bearing gap, and the inner ring 1 and the outer ring 2 are relatively displaceable in the axial direction. Since the intermediate lip 12 constitutes the parallel tip portion 12a which is substantially parallel to the bottom of the seal groove 9 in the bearing axial direction, the inner ring 1 and the outer ring 2 do not come into contact with each other even if they are relatively displaced in the axial direction, The torque due to the contact of the seal does not increase.

Next, the outer lip 13 which is the third lip
Is located on the outer side of the bearing and forms a narrow gap with the outer peripheral surface 1c of the inner ring shoulder to prevent foreign matter from entering from the outside of the bearing. Also, like the intermediate lip 12,
In order to prevent the inner ring 1 and the outer ring 2 from coming into contact with each other even if the inner ring 1 and the outer ring 2 are relatively displaced in the axial direction, the inner ring 1 and the outer ring 2 have a parallel portion 13a that is substantially parallel to the bearing axial direction with respect to the outer peripheral surface 1c of the inner ring. The torque does not increase due to the contact of the seal member 5.

The degassing groove 15 of the inner lip 11 serves the following function. Generally, when a bearing is operated, the bearing temperature rises due to the friction loss inside the bearing, the stirring loss of the lubricant, and the seal contact torque. If the pressure inside the bearing drops due to the bearing operating temperature being stopped and the bearing temperature dropping,
There may be a pressure difference between the outside of the bearing and the sticking phenomenon at the seal contact portion. If the inner lip 11 serving as a contact seal is provided with the gas vent groove 15 as described above, gas passes between the outside of the bearing and the inside of the bearing, the pressure difference can be eliminated, and the seal contact portion is fixed. The phenomenon can be prevented.

FIG. 3 shows a second embodiment of the present invention.
In this example, in the first embodiment, the lip support portion 7a of the elastic body 7 is arranged on the inner diameter side of the inner diameter end 6a of the core metal 6 of the seal member 5 in the radial direction, and the constricted portion 16 is formed on the lip support portion 7a. Is provided. When used in high-speed rotation or when used in outer ring rotation like an automobile pulley, the axial fluctuation frequency of the inner ring and outer ring increases, and the rubber elasticity of the seal member follows the displacement. It may not be possible to reduce the sealing performance. In the above-mentioned conventional example (actual flat blade 2-2526), a constricted portion is provided to improve the followability of the lip. However, if the lip portion is simply provided, when the outer ring 2 rotates, it is positioned on the inner diameter side of the constricted portion. There is a phenomenon that the rotating lip opens due to centrifugal force, which leads to deterioration of sealing performance. In this embodiment,
The above problem is solved as follows by disposing the lip support portion 7a of the elastic body 7 on the radially inner side of the inner diameter end 6a of the core metal 6 and providing the lip support portion 7a with the constricted portion 16.

By disposing the lip support portion 7a on the inner diameter side in the radial direction of the inner diameter end 6a of the core metal, even when the seal member 5 is rotated by the outer ring rotation, the lip support portion 7a is formed.
Inner lips 11, which are the lips arranged on the inner diameter side of the
It is possible to prevent the intermediate lip 12 and the outer lip 13 from opening due to centrifugal force, increase the seal contact torque due to excessive contact of the inner lip 11, and the inner lip 11 is not in contact with the seal groove inner side wall 9b. It is prevented that the sealing performance is deteriorated. Further, by providing the constricted portion 16, the rigidity of the lip support portion 7a is reduced, and when the seal contact resistance is the same, at the contact portion between the inner lip 11 and the seal groove inner side wall 9b, the seal tightening at the time of design is performed. Since a large margin can be secured, it is possible to reduce deterioration of the sealing performance when the inner ring 1 and the outer ring 2 are axially displaced relative to each other.

In this embodiment, other matters are the same as those in the first embodiment. Also in each of the following embodiments, other matters than the matters particularly described are the same as those in the first embodiment.

FIG. 4 shows a third embodiment. This example
In the first embodiment, in the elastic body 7 of the seal member 5,
As the fourth lip, a grease lip 14 is provided which forms a non-contact radial gap with the outer peripheral surface 1b of the inner ring inner shoulder portion. This embodiment is particularly applicable to applications in which operating conditions require a lubricant retention function. By providing the grease lip 14, the circulation flow of the lubricant inside the bearing can be improved, and a narrow gap that is not in contact with the outer peripheral surface 1b of the inner ring inner shoulder is formed to retain the lubricant. The force can be increased and the leakage of the lubricant can be prevented.

FIG. 5 shows a fourth embodiment of the present invention.
In this example, the contact angle β outside the bearing is smaller than the contact angle α inside the bearing with respect to the contact angle between the inner lip 11 and the inner wall 9b of the seal groove in the first embodiment. The contact angle β on the outside of the bearing is the angle formed by the surface of the inner lip 11 and the inner wall 9 b of the seal groove toward the outside of the bearing. The contact angle α on the bearing inner side is an angle formed by the surface of the inner lip 11 and the inner wall 9 b of the seal groove toward the inner side of the bearing. In this way, by making the contact angle β outside the bearing smaller than the contact angle α inside the bearing, the inner lip 11
By holding the grease in the vicinity of, the effect of preventing foreign matter from entering the inside of the bearing is effectively obtained, and the effect of preventing foreign matter from entering from the outside is further promoted. The seal groove 9 with which the rubber seal for bearings comes into contact is usually turned and finished, and has a large surface roughness of about 2 to 6 μmRa, and the contact force of the seal portion is only the bending deformation force of synthetic rubber. Is very small. Therefore, since it becomes difficult to generate a pressure gradient in a direction perpendicular to the movement direction by the rotational force, a large hydrodynamic sealing effect cannot be expected. In a bearing seal having a small contact pressure, the fluid retainer function obtained by the surface tension action due to the small wedge angle is a dominant factor in the sealing mechanism. To use this sealing mechanism,
The presence of the intermediate lip 12, which is the lip of, is essential.
Since the flow of the lubricant leaking from the inside of the bearing is blocked by the intermediate lip 12, the lubricant having a large viscosity can be collected at the bottom of the seal groove 9. Then, the lubricant that has accumulated at the bottom of the seal groove accumulates in a portion that forms a bearing external contact angle β having a small contact angle, and thus has a function of preventing foreign matter from entering from the outside of the bearing.

FIG. 6 shows a fifth embodiment of the present invention.
In this example, in the second embodiment described with reference to FIG. 3, the lip support portion 7a is arranged on the inner diameter side in the radial direction of the inner diameter end 6a of the core metal 6 of the seal member 5, and the constricted portion 16 is formed on the lip support portion 7a. Is provided. In the case of this example, the effects due to the relationship between the contact angles α and β and the effects due to the arrangement of the lip support portion 7a and the formation of the constricted portion 16 are combined.

FIG. 7 shows a sixth embodiment of the present invention.
This example is the same as the third embodiment described with reference to FIG.
As the fourth lip, a grease lip 14 that forms a non-contact gap with the inner ring inner shoulder outer peripheral surface 1b is provided inside the bearing.

With respect to the rolling bearings of the above-mentioned respective embodiments (FIGS. 1 and 2 to 7), a test bearing was manufactured and the results of the test are shown in Table 1. The drawing numbers in the table are the drawing numbers of the drawings showing the above-described embodiments. The description in the column next to the figure number in the table shows the features of each embodiment. The test conditions were a rotation speed of 3600 rpm and a test at room temperature. Grease leakage was judged by the degree of grease leakage to the bearing surface. In the muddy water test, the lower half of the bearing was immersed in muddy water, and the state of infiltration of muddy water into the bearing was visually determined.

[0031]

[Table 1]

[0032]

In the rolling bearing of the present invention, a seal member is composed of a rubber-like elastic body and a core metal, the seal member is fixed to the inner peripheral portion of the outer ring, and a seal groove is formed on the outer peripheral surface of the inner ring. In the above rolling bearing, the seal groove of the inner ring has a bottom surface formed into a flat cylindrical surface, and the elastic body has a lip support portion extending from the inner diameter end of the core metal to the inner diameter side. The inner lip that contacts the inner groove of the inner ring seal groove and the inner wall that contacts the inner wall of the seal groove, and the parallel tip with the bottom surface of the inner ring seal groove that is substantially parallel to the bearing axis are arranged in non-contact. And an outer lip that has a portion facing the outer peripheral surface of the shoulder portion outside the inner ring seal groove and that is located in a non-contact manner with a gap between the outer peripheral surface of the shoulder portion and the outer peripheral surface of the shoulder portion. Since 3 lips of are arranged, the seal part Without increasing the contact torque, none of the two performance required in the seal of lubricant leakage and foreign matter from the outside intrusion can be improved. If the lip support is located on the inner diameter side in the radial direction of the inner diameter end of the core metal, the phenomenon in which each lip opens due to centrifugal force is prevented, and the seal contact torque increases due to excessive contact of the inner lip, and there is no contact. Therefore, the sealing performance is prevented from being deteriorated. Further, when the lip supporting portion is provided with the constricted portion, a large seal tightening margin can be secured, and deterioration of the sealing performance when the inner ring and the outer ring are relatively displaced in the axial direction can be reduced. When the contact angle between the inner lip and the inner wall of the seal groove is smaller than the contact angle on the outer side of the bearing, the effect of preventing foreign matter from entering from the outside is improved. In the case where the above-mentioned elastic body is provided with a grease lip that forms a non-contact radial gap between the elastic body and the outer peripheral surface of the inner ring inner shoulder portion, lubrication of the inside of the bearing is not caused without increasing torque. The effect of preventing leakage of the agent is enhanced, which is preferable depending on the application. A gas vent groove that allows gas to pass between the outside of the bearing and the inside of the bearing,
When the inner lip is provided at a plurality of positions on the peripheral edge of the tip, the pressure difference between the inside and outside of the bearing due to changes in the bearing temperature can be eliminated, and the sticking phenomenon of the seal contact portion can be prevented.

[Brief description of drawings]

FIG. 1A is a sectional view of a rolling bearing according to a first embodiment of the present invention, and FIG. 1B is an enlarged sectional view of a portion B thereof.

FIG. 2A is a front view of a seal member of the rolling bearing,
(B) is a sectional view taken along line II-II of FIG.

FIG. 3 is a partially enlarged sectional view of a second embodiment of the present invention.

FIG. 4 is a partially enlarged sectional view of a third embodiment of the present invention.

FIG. 5 is a partially enlarged sectional view of a fourth embodiment of the present invention.

FIG. 6 is a partially enlarged sectional view of a fifth embodiment of the present invention.

FIG. 7 is a partially enlarged sectional view of a sixth embodiment of the present invention.

[Explanation of symbols]

1 ... Inner ring 1b, 1c ... Shoulder peripheral surface 2 ... Outer ring 3 ... rolling elements 5 ... Seal member 6 ... core 7 ... Elastic body 7a ... Lip support 9 ... Seal groove 9a ... Bottom of seal groove 9b ... Inside wall of seal groove 9c ... Seal groove outer wall 11 ... Inner lip 12 ... Middle lip 13 ... Outer lip 14 ... Grease lip α ... Contact angle on the inside of the bearing β ... Bearing outside contact angle L ... gap

Claims (5)

[Claims] 1. A rubber-like elastic body and a core metal constitute a seal member, and the seal member is fixed to an inner peripheral portion of an outer ring,
In a rolling bearing in which a seal groove is formed on the outer peripheral surface of the inner ring, the seal groove of the inner ring has a flat bottom surface with a cylindrical surface, and the elastic body is a lip support extending from the inner diameter end of the cored bar to the inner diameter side. Inner lip that contacts the inner groove of the inner ring seal groove and the inner wall of the seal groove on the inner diameter side of the lip support, and a parallel tip that is approximately parallel to the bearing axial direction with respect to the bottom surface of the inner ring seal groove. Contactlessly disposed with a gap between the intermediate lip which is arranged in a non-contact manner so as to have a portion, and a portion which faces the outer peripheral surface of the shoulder portion outside the bearing of the inner ring seal groove and which has an outer peripheral surface of the shoulder portion. The rolling bearing is characterized in that there are three outer lips and an outer lip arranged on the outer lips. 2. The rolling bearing according to claim 1, wherein the lip support portion is arranged on an inner diameter side of the inner diameter end of the core metal in the radial direction, and the lip support portion is provided with a constricted portion. 3. The contact angle on the outside of the bearing, which is the angle formed by the surface of the inner lip and the inner wall of the seal groove toward the outer side of the bearing at the angle of contact between the inner lip and the inner wall of the seal groove, The rolling bearing according to claim 1 or 2, which is configured to be smaller than a contact angle on the bearing inner side, which is an angle formed by the surface of the inner lip and the inner wall of the seal groove when facing. 4. The grease according to claim 1, wherein the elastic body is provided with, as a fourth lip, a grease lip that forms a non-contact radial gap with the outer peripheral surface of the inner ring inner shoulder portion. Rolling bearing described in. 5. A gas vent groove, which allows gas to pass between the outside of the bearing and the inside of the bearing, is provided at a plurality of positions along the peripheral edge of the tip of the inner lip. Rolling bearing.