JP2018119648A - Oil seal and bearing with seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict, in an oil seal which can bring a gap between a seal lip of a seal member and a mating member into a fluid lubrication state by means of a plurality of protrusions, elastic deformation of a portion between the protrusions of the seal lip without increasing the number of the protrusions.SOLUTION: A seal lip 10 is considered to be sectioned in a circumferential direction in accordance with the existence or non-existence of a protrusion 11. The stiffness of a second section A2 of the seal lip 10 without the protrusion 11 is higher than that of a first section A1 with the protrusion 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an oil seal used to prevent foreign matters in lubricating oil from entering the internal space of the apparatus, and a bearing with a seal including the oil seal.

  For example, foreign substances such as gear wear powder are mixed in transmissions mounted on vehicles such as automobiles and various construction machines. By adopting a sealed bearing having an oil seal as a rolling bearing that rotatably supports the rotation shaft of the transmission, foreign matter intrusion into the internal space of the bearing is prevented and early damage of the bearing is prevented.

  As such an oil seal, one having a seal member having a seal lip formed of a rubber material and a counterpart member that rotates relative to the seal member in the circumferential direction is used. The mating member is, for example, a race ring, a slinger, or the like, and has a seal sliding surface for slidingly contacting the seal lip. Even if there is an eccentricity between the seal member and the mating member, a tightening allowance is set between the seal lip and the seal sliding surface of the mating member so that the seal lip can sufficiently follow the seal sliding surface. It is common to do. When the seal member and the mating member are arranged in a predetermined manner, the seal lip presses the seal sliding surface of the mating member due to the tightening allowance. For this reason, at the time of relative rotation between the seal member and the mating member, drag resistance (seal torque) of the seal lip that comes into sliding contact with the seal sliding surface is generated. Moreover, the friction of the sliding contact causes a temperature rise. As the temperature rises, an adsorption action due to a pressure difference between the internal space and the outside is caused, and the friction increases.

  On the other hand, it has been proposed that a fluid lubrication state is established between the seal lip and the seal sliding surface of the mating member (Patent Document 1). The seal member disclosed in Patent Document 1 has a seal lip formed with a large number of protrusions arranged at predetermined intervals in the circumferential direction. The protrusion forms a wedge-shaped gap with the seal sliding surface of the mating member. When the mating member rotates at a predetermined speed or more relative to the seal member, the lubricating oil is dragged into the wedge-shaped gap, and the formation of an oil film is promoted by the wedge effect. Make sliding contact with seal sliding surface in fluid lubrication. For this reason, the seal lip and the seal sliding surface of the mating member are completely separated.

  Here, the fluid lubrication state refers to a state in which a fluid film of lubricating oil is formed between two surfaces by a hydrodynamic principle, and a direct contact between friction surfaces is not generated. When the minimum oil film thickness between the two surfaces is larger than the root mean square roughness, generally three times or more, it can be regarded as a fluid lubrication state. When fluid lubrication occurs between the seal lip and the seal sliding surface of the mating member, the sliding resistance becomes almost zero, so the seal torque can be greatly reduced, which is impossible with conventional oil seals. It can be used at high peripheral speeds. Further, by setting the height of the protrusions, it is possible to prevent foreign matters having a particle size of a predetermined size or more from passing through the gaps between the protrusions, thereby preventing entry into the internal space of the apparatus.

International Publication No. WO2016 / 143786

  However, the seal lip of Patent Document 1 has a uniform cross-sectional shape over the entire circumference in the circumferential direction except for the projections, and the rigidity of the portion between the projections adjacent in the circumferential direction is relatively low. The portion extending between the protrusions extends along the circumferential direction in the natural state, but due to the tightening force resulting from the above-described tightening allowance, the portion 101 extending between the protrusions 100 is elastically deformed as shown in FIG. Then, it approaches the seal sliding surface 103 side of the mating member 102. As a result, the gap 104 between the portion 101 and the seal sliding surface 103 is smaller than the height H of the protrusion 100. This can cause an increase in seal torque. In particular, as the circumferential distance P between the protrusions 100 adjacent in the circumferential direction increases, that is, as the number of protrusions decreases, the gap 104 becomes too small and the concern about an increase in seal torque increases.

  In order to reduce the aforementioned elastic deformation of the seal lip portion 101, if the number of the protrusions 100 is increased and the interval P between the protrusions 100 is decreased, the viscous resistance between the protrusion 100 and the seal sliding surface 103 is reduced. This increases and causes a problem that causes an increase in seal torque. Considering the Stribeck diagram, within the range of the fluid lubrication state, the smaller the area and the higher the surface pressure, the lower the torque. Therefore, there is a gap between the portion other than the protrusion 100 of the seal lip and the seal sliding surface 103. Assuming that 104 can be secured, the protrusions 100 should be small in the circumferential direction and have a small number of protrusions (the number of protrusions 100 aligned in the circumferential direction in one turn).

  In view of the above background, the problem to be solved by the present invention is an oil seal that can be in a fluid lubrication state with a plurality of protrusions formed on the seal lip between the seal lip of the seal member and the mating member. An object of the present invention is to suppress elastic deformation in a portion extending between the protrusions of the seal lip without increasing the number of protrusions of the seal lip.

  As a first means for achieving the above object, the present invention includes a seal member having a seal lip formed of a rubber material, and a counterpart member that rotates relative to the seal member in the circumferential direction, A tightening margin is set between the seal sliding surface formed on the mating member and the seal lip, and the seal lip surrounds a plurality of protrusions that are in sliding contact with the seal sliding surface in a fluid lubricated state. In the oil seal having a predetermined interval in the direction, the seal lip is considered to be divided in the circumferential direction by the presence or absence of the protrusion, and the region where the protrusion is present is the first region of the seal lip, and the protrusion is present When the area not to be used is the second area, a configuration is adopted in which the rigidity of the second area is higher than the rigidity of the first area.

  If the rigidity of the second region including the portion between the adjacent protrusions in the circumferential direction of the seal lip is made higher than the rigidity of the first region where the protrusion exists, the tightening force of the seal lip acts. When doing so, the elastic deformation in the part over the said processus | protrusion is suppressed. For this reason, it becomes possible to suppress elastic deformation in the portion extending between the projections without increasing the number of projections of the seal lip. Note that the rigidity of the second region can be improved without increasing the tightening force of the seal lip.

  For example, the second region of the seal lip may have a reinforcing portion that is formed larger in a direction along the seal sliding surface or in a direction away from the seal sliding surface than the first region. If it does in this way, the rigidity of the 2nd field can be made higher than the rigidity of the 1st field, without increasing the thickness of the 2nd field to the seal sliding face side.

  For example, the seal lip has a solid portion that is continuous in the entire circumferential direction so as to connect the plurality of protrusions, and the reinforcing portion is between the protrusions adjacent in the circumferential direction among the solid portions. It is continuous only in the span.

  For example, the second region of the seal lip may have a cured portion made of the rubber material in a cured state as compared to the rubber material forming the first region. If it does in this way, the rigidity of the 2nd field can be made higher than the rigidity of the 1st field.

  As a second means for achieving the above object, the present invention comprises a seal member having a seal lip formed of a rubber material, and a counterpart member that rotates relative to the seal member in the circumferential direction, A tightening margin is set between the seal sliding surface formed on the mating member and the seal lip, and the seal lip surrounds a plurality of protrusions that are in sliding contact with the seal sliding surface in a fluid lubricated state. In the oil seal having a predetermined interval in the direction, considering the state before and after the seal member is disposed with respect to the mating member, an arbitrary cross section along the radial direction of the seal member, When divided into a first cross-sectional area that is substantially displaced in a direction perpendicular to the seal sliding surface and a second cross-sectional area that is not substantially displaced in the perpendicular direction, The second The rigidity of the boundary portion between the cross-sectional area is adopted a structure that is higher than the rigidity of the first cross-sectional area.

  When the seal member is arranged with respect to the mating member, the seal lip has a tightening margin that is set between the seal lip and the seal lip. Power is generated. The deflected seal lip has a portion that is displaced in a direction perpendicular to the seal sliding surface. However, considering the entire seal member, the amount of displacement in the direction perpendicular to the seal sliding surface during installation decreases according to the distance from the tip of the seal lip (the place where the tightening margin is the largest). Where the distance is above a certain level, the amount of displacement is almost gone and can be ignored dynamically. That is, when comparing the state before and after mounting the seal member in a predetermined manner with respect to the mating member, an arbitrary cross section along the radial direction of the seal member is in a direction perpendicular to the seal sliding surface. It can be divided into a first cross-sectional area that is substantially displaced and a second cross-sectional area that is not substantially displaced in the perpendicular direction. If the rigidity at the boundary between the second cross-sectional area and the first cross-sectional area is set higher than the rigidity of the seal lip in the first cross-sectional area, a plurality of protrusions are connected in the seal lip. Thus, compared to the solid part that is continuous in the entire circumference, the part that supports the solid part has improved rigidity, and when the seal lip's tightening force is applied, the part that extends between the protrusions of the solid part The amount of elastic deformation at is reduced. For this reason, it becomes possible to suppress elastic deformation in the portion extending between the projections without increasing the number of projections of the seal lip. Note that the tension of the seal lip does not increase.

  For example, the sealing member may have an annular cored bar formed of a metal plate, and the cored bar may have an edge portion disposed at the boundary portion. If it does in this way, the rigidity in the boundary part of the 2nd section field can be made high with a metal core.

  For example, the seal member includes an annular cored bar formed of a metal plate and a reinforcing ring formed of a material having higher rigidity than the rigidity of the rubber material, and the reinforcing ring includes the boundary It is good to arrange in the part. If it does in this way, the rigidity in the boundary part of the 2nd section field can be made high with a reinforcement ring. In addition, since it is possible to reduce the rigidity by reducing the thickness of the seal lip portion connecting the core metal and the reinforcing ring, the reinforcing ring is also eccentric according to the eccentricity of the mating member (the mating member and the reinforcing ring are always The position of the seal lip is improved when the eccentricity is large.

  The bearing with a seal provided with the oil seal according to the present invention, wherein the seal member separates the bearing internal space from the outside, while preventing foreign matter from entering the internal space of the bearing with the seal member, The bearing torque is reduced by a significant reduction in the seal torque. For this reason, this bearing with a seal | sticker is suitable for the use which supports the rotating shaft of the transmission of a motor vehicle.

  In the present invention, by adopting the configuration according to the first means or the second means, a plurality of protrusions formed on the seal lip between the seal lip of the seal member and the mating member can be brought into a fluid lubrication state. In a possible oil seal, it is possible to suppress elastic deformation in the portion extending between the seal lip protrusions without increasing the number of protrusions on the seal lip, and as a result, between the protrusions of the seal lip while reducing the number of protrusions etc. Thus, the gap between the part and the mating member can be appropriately maintained, and the seal torque can be further reduced.

The partial front view which shows the oil seal which concerns on 1st embodiment of this invention Sectional drawing which shows a bearing with a seal provided with the oil seal of FIG. Partial expanded sectional view which shows the cross section of the III-III line of FIG. Partial sectional view showing the action of the protrusion according to the first embodiment The partial front view which shows the oil seal which concerns on 2nd embodiment of this invention Partial expanded sectional view which shows the cut surface in the VI-VI line of FIG. The partial front view which shows the oil seal which concerns on 3rd embodiment of this invention Partial expanded sectional view which shows the cut surface of the VIII-VIII line of FIG. Partial sectional view showing an oil seal according to a fourth embodiment of the present invention Partial front view of the oil seal according to the fourth embodiment Partial sectional view showing an oil seal according to a fifth embodiment of the present invention Sectional drawing which shows an example of a transmission provided with the bearing with a seal concerning this invention The figure which shows the mode of the elastic deformation of the seal lip of a prior art example with the cross section along the circumferential direction

  Hereinafter, a first embodiment according to the present invention will be described with reference to FIGS. The first embodiment is an example of an oil seal that employs the first means and a bearing with a seal including the oil seal.

  As shown in FIG. 2, the oil seal includes a seal member 1 and a counterpart member 2 that rotates relative to the seal member 1 in the circumferential direction. The bearing with seal includes a mating member 2 formed of an inner ring, an outer ring 4 that forms an annular bearing inner space 3 between the mating member 2, and a predetermined number interposed between the raceway of the mating member 2 and the raceway of the outer ring 4. The rolling element 5 is provided. The seal member 1 separates between the bearing internal space 3 and the outside (bearing periphery).

  The mating member 2 is attached to a rotating shaft (not shown) and rotates integrally with the rotating shaft. The rotating shaft is provided as a rotating portion of a vehicle transmission, a differential, a constant velocity joint, a propeller shaft, a turbocharger, a machine tool, a wind power generator, or a wheel bearing, for example. The outer ring 4 is attached to a member (not shown) that applies a load from the rotating shaft, such as a housing and a gear. This bearing with seal supports a rotating shaft rotatably.

  Lubricating oil is supplied to the sealed bearing from the outside by appropriate means such as splashing or an oil bath. On the outside side with the seal member 1 as a boundary, there are foreign matters according to the mounting destination of the bearing, such as gear wear powder, clutch wear powder, and fine crushed stone. Such powdery foreign matter can reach the vicinity of the bearing with seal by the flow of lubricating oil or atmosphere. The seal member 1 prevents foreign matter from entering the bearing internal space 3 from the outside.

  Hereinafter, the direction along the central axis (not shown) of the seal member 1 is referred to as “axial direction”. The axial direction corresponds to the left-right direction in FIG. A direction perpendicular to the axial direction is referred to as a “radial direction”. The radial direction corresponds to the vertical direction in FIG. The circumferential direction around the central axis is referred to as “circumferential direction”. The central axis of the mating member 2 is set coaxially with the central axis of the seal member 1 by design.

  A seal groove 6 is formed at an inner peripheral end of the outer ring 4. On the outer periphery of the mating member 2, a seal sliding surface 7 is formed along the circumferential direction. The seal member 1 is attached to the outer ring 4 by press-fitting the outer peripheral edge of the seal member 1 into the seal groove 6.

  The seal sliding surface 7 has a cylindrical surface shape. The maximum height roughness Rz of the seal sliding surface 7 is 2.5 μm or less (preferably less than 1 μm). Here, the maximum height roughness Rz refers to the maximum height roughness defined in JIS standard B0601: 2013.

  The seal member 1 includes an annular cored bar 8 formed of a metal plate and a rubber material 9 attached to the cored bar 8. The entire sealing member 1 is composed of a core metal 8 and a rubber material 9. The cored bar 8 has an annular plate shape that is continuous along the entire circumference in the circumferential direction. The material of the cored bar 8 is made of a metal having higher rigidity than that of the rubber material 9. For example, a steel plate can be cited as a material for the cored bar 8 suitable for press working. The rubber material 9 is vulcanized and bonded to the core metal 8. The type of the rubber material 9 is not particularly limited, and examples thereof include nitrile rubber and fluorine rubber.

  The seal member 1 has a seal lip 10 formed of a rubber material 9. The seal lip 10 is made of a part of a rubber material 9 extending from the edge 8 a of the core metal 8 toward the seal sliding surface 7. The edge 8 a of the cored bar 8 is an inner peripheral edge or an outer peripheral edge of the cored bar 8 that defines a diameter closer to the seal sliding surface 7 among the inner diameter or the outer diameter of the cored bar 8.

  The seal lip 10 is a radial lip. Here, the radial lip exhibits a sealing action with a seal sliding surface along the axial direction such as the seal sliding surface 7 or a seal sliding surface with an acute angle gradient within 45 ° with respect to the axial direction. A seal lip having a radial tightening margin with respect to the seal sliding surface. When the seal member 1 is attached to the outer ring 4, the seal lip 10 is pressed against the seal sliding surface 7 by tightening allowance. For this reason, the seal lip 10 is elastically deformed so as to bend, and generates a force (tightening force) for pressing the seal sliding surface 7 in the radial direction. The mounting error, manufacturing error, eccentricity between the mating member 2 and the outer ring 4 are absorbed by the elastic deformation of the seal lip 10.

  In addition, although the radial lip was illustrated as the seal lip 10, you may change to an axial lip. The axial lip is a seal sliding surface along the radial direction or a seal sliding surface having an acute angle gradient of less than 45 ° with respect to the radial direction and a sealing lip that exhibits a sealing action. It has an axial allowance in between.

  As shown in FIGS. 1 and 3, the seal lip 10 includes a plurality of protrusions 11 arranged at predetermined intervals in the circumferential direction, and a solid portion 12 that is continuous in the entire circumferential direction so as to connect the plurality of protrusions 11. Have.

  When the cross section of the seal lip 10 cut along an arbitrary virtual axial plane with the central axis of the seal member 1 as one side is considered, the solid portion 12 occupies the same cross sectional area in any cross section.

  The protrusion 11 extends long in the direction orthogonal to the circumferential direction on the surface portion of the seal lip 10 facing the seal sliding surface 7 (the surface facing the inner diameter side in the drawing). As shown in FIGS. 1 and 4, the protrusions 11 are arranged at a constant interval P in the circumferential direction. That is, when considered around the central axis of the seal member 1, the plurality of protrusions 11 are arranged at a constant pitch angle. The interval P can be set to, for example, 0.2 mm or more and 3.0 mm or less (preferably 0.2 mm or more and 1.5 mm or less).

  The protrusion 11 forms a wedge-shaped gap with the seal sliding surface 7. Here, the wedge-shaped gap refers to a gap that gradually narrows in the radial direction toward the projection 11 in the circumferential direction. The surface of the protrusion 11 has a circular arc shape in a cross section along the circumferential direction. Here, the cross section along the circumferential direction of the protrusion 11 refers to a cross section of the protrusion 11 when the protrusion 11 is cut by a virtual plane orthogonal to the seal sliding surface 7 and extending along the circumferential direction. In this cross-sectional shape, the aforementioned arc-shaped radius R is, for example, 0.4 mm or more and less than 9.0 mm (preferably 0.4 mm or more and 6.0 mm or less, more preferably 0.4 mm or more and 3.0 mm). Can be set to:

  The protrusion 11 has a height H toward the seal sliding surface 7 of the counterpart member 2. Here, the height H of the protrusion 11 refers to a height in a direction perpendicular to the seal sliding surface 7 in a cross section along the circumferential direction. Since the seal sliding surface 7 has the above-described cylindrical surface shape, the direction perpendicular thereto corresponds to the radial direction, and the height H of the protrusion 11 corresponds to the specific height in the radial direction from the solid portion 12. . Each protrusion 11 is a location that defines a tightening allowance for the seal sliding surface 7.

  The height H of the protrusion 11 is smaller than the radius R of the protrusion 11, for example, 0.01 mm or more and less than 0.10 mm (preferably 0.01 mm or more and 0.08 mm or less, more preferably 0.01 mm or more, 0 .05 mm or less).

  Considering that the seal lip 10 is divided in the circumferential direction by the presence or absence of the protrusion 11, the area where the protrusion 11 exists in the seal lip 10 is defined as a first area A <b> 1 and the area where the protrusion 11 does not exist is defined as a second area A <b> 2. . That is, when considering a cross section obtained by cutting the seal lip 10 on an arbitrary virtual axial plane with the central axis of the seal member 1 as one side, the portion of the seal lip 10 including the cross section of the protrusion 11 corresponds to the first region A1. The area not including the cross section of the protrusion 11 corresponds to the second area A2, and the boundary between the first area A1 and the second area A2 is the virtual axial planes Pax1 and Pax2 at both ends in the circumferential width of the protrusion 11 in FIG. . Considering clockwise in the figure, the area from the virtual axial plane Pax1 to the virtual axial plane Pax2 is the first area A1, and the area from the virtual axial plane Pax2 to the virtual axial plane Pax1 is the second area A2. Each first region A1 has the same structure, and each second region A2 has the same structure.

  As shown in FIGS. 1 and 3, the second region A <b> 2 has a reinforcing portion 13 that is formed larger in the direction along the seal sliding surface 7 than the first region A <b> 1. The reinforcing portion 13 is continuous only in a portion of the solid portion 12 extending between the protrusions 11 adjacent in the circumferential direction, and extends from the portion in a direction along the seal sliding surface 7 and in a direction intersecting with the circumferential direction. It has been extended. In the second region A <b> 2, a series of portions formed by the portion between the protrusions 11 of the solid portion 12 and the reinforcing portion 13 exhibit rigidity that resists the tightening force of the seal lip 10. For this reason, compared with the cross section of 1st area | region A1 without the reinforcement part 13, the rigidity of 2nd area | region A2 whose cross-sectional area was expanded by the reinforcement part 13 becomes high compared with the rigidity of 1st area | region A1. Yes. Thereby, the elastic deformation which the 2nd area | region A2 (especially the part ranging between the protrusions 11 of the solid part 12) produces by the influence of the above-mentioned tension | tensile_strength is suppressed effectively. Since the rigidity of the first region A1 including the protrusion 11 does not increase, the tightening force of the seal lip 10 is not increased.

  Since the elastic deformation of the second region A2 is very small, the state of the elastic deformation is not particularly illustrated, but the elastic deformation is suppressed so that the hydrodynamic influence on the flow of the lubricating oil can be ignored. Thus, it is not necessary to suppress slight elastic deformation, and in order to reduce the seal torque, the second region can ensure the gap 14 between the second region A2 and the seal sliding surface 7. It is only necessary to suppress the elastic deformation of A2, and some elastic deformation may be allowed.

  When the seal member 1 is attached, the seal lip 10 is in contact with the seal sliding surface 7 only by the projections 11 and communicates between the bearing inner space 3 and the outside between the projections 11 adjacent in the circumferential direction. Therefore, the second region A2 and the seal sliding surface 7 are not in direct contact with each other. In the direction perpendicular to the seal sliding surface 7 between the second region A2 and the seal sliding surface 7, the size of the gap 14 is not larger than the height H of the protrusion 11, but the reinforcing portion 13 is ensured at a predetermined ratio or more with respect to the height H of the protrusions 11 by increasing the rigidity of the second region A2 including 13.

  During operation of the bearing with seal, the counterpart member 2 rotates relative to the seal member 1 (see FIG. 4). Lubricating oil (for example, transmission oil) supplied from the outside during operation enters the gap 14 formed between the protrusions 11 adjacent in the circumferential direction, and lubricates between the seal lip 10 and the counterpart member 2. Here, as shown in FIG. 4, each protrusion 11 of the seal lip 10 has an arc shape with a radius R of 0.4 mm or more and less than 9.0 mm in the cross section along the circumferential direction. When the moving surface 7 moves in the circumferential direction with respect to each protrusion 11, the lubricating oil is effectively dragged into the sliding contact portion between the protrusion 11 and the mating member 2 along the surface of each protrusion 11. At this time, the formation of an oil film is promoted by the wedge effect, the lubrication state of the sliding contact portion between each protrusion 11 of the seal lip 10 and the mating member 2 becomes a fluid lubrication state, and the seal torque is drastically reduced. Further, since the seal torque is small, frictional heat between the seal lip 10 and the counterpart member 2 is hardly generated. Furthermore, the lubricating oil supplied from the outside passes between the seal lip 10 and the mating member 2 through the gap 14, so that the frictional heat between the seal lip 10 and the mating member 2 is dissipated. . Therefore, it is possible to extremely effectively suppress the temperature rise of this sealed bearing.

  Further, in this bearing with seal, the circumferential interval P between the protrusions 11 is set to 3.0 mm or less (preferably 1.5 mm or less). It is possible to secure the thickness of the oil film formed between each of the projections 11 and the mating member 2 and to effectively generate the wedge effect. Further, since the interval P between the protrusions 11 is 0.2 mm or more, it is possible to reduce the manufacturing cost of the mold for manufacturing the seal lip 10.

  Moreover, since the height H of the protrusion 11 is set to 0.01 mm or more in this bearing with seal, it is possible to effectively generate a wedge effect under general use conditions of the bearing. Further, by setting the height H of the protrusion 11 to 0.01 mm or more, it is possible to reliably form the protrusion 11 when the seal lip 10 is manufactured with a mold. In addition, since the height H of the protrusion 11 is less than 0.10 mm (preferably 0.08 mm or less, more preferably 0.05 mm or less), foreign matters that adversely affect the bearing life are in the bearing internal space 3. It is possible to effectively prevent intrusion.

  In addition, if the particle size of the foreign matter contained in the lubricating oil in the internal space of the rolling bearing is 50 μm or less, the life ratio of the rolling bearing (ratio of the actual life to the calculated life) can sufficiently withstand practical use in an automobile transmission. A value (for example, about 7 to 10 times) is shown. Therefore, when the height H of the protrusion 11 is 0.01 mm or more and less than 0.10 mm (preferably 0.01 mm or more and 0.08 mm or less, more preferably 0.01 mm or more and 0.05 mm or less), In particular, the sealing performance of the bearing can be ensured in practical use in an automobile transmission.

  In addition, the oil seal has a higher rigidity in the second region A2 including the portion extending between the adjacent protrusions 11 in the circumferential direction than the rigidity of the first region A1 where the protrusions 11 exist. Elastic deformation at a portion between the protrusions 11 of the lip 10 is suppressed (see FIGS. 1 and 4). Thereby, this oil seal can suppress elastic deformation in a portion extending between the protrusions 11 without increasing the number of protrusions of the seal lip 10. It is not necessary to increase the thickness of the seal lip 10 in the first region A1 where the protrusions 11 are present, and it is possible to improve the rigidity of the second region A2 without increasing the tightening force.

  Therefore, this oil seal effectively reduces the sealing torque between each protrusion 11 and the seal sliding surface 7 by fluid lubrication by reducing the radius R of the protrusions 11, the number of protrusions, and the interval P between the protrusions 11. On the other hand, the gap 14 is kept at an appropriate size between the second region A2 and the seal sliding surface 7 without allowing direct contact, and the lubricating oil between the second region A2 and the seal sliding surface 7 is maintained. It is possible to effectively reduce the seal torque due to the shearing and further reduce the seal torque.

  Moreover, since this oil seal employs the second region A2 having the reinforcing portion 13 formed larger in the direction along the seal sliding surface 7 than the first region A1, the second region A2 The rigidity of the second region A2 can be made higher than that of the first region A1 without increasing the thickness of the first region A2 toward the seal sliding surface 7 (see FIGS. 1 and 3).

  As a modification example of the reinforcing portion, the second embodiment is shown in FIGS. In the following, only differences from the first embodiment will be described.

  In the second region A2 of the seal lip 20 according to the second embodiment, the reinforcing portion according to the first embodiment is omitted, and the direction away from the seal sliding surface 7 as compared with the first region A1 (in this example, It is different in that it has a reinforcing portion 21 that extends greatly in the radially outward direction. The reinforcing portion 21 is continuous only with the portion 12 a extending between the protrusions 11 of the solid portion 12. In the second region A2, since the series of portions of the solid portion 12 and the reinforcing portion 21 exhibit rigidity, the second region A2 can be increased without increasing the thickness of the second region A2 toward the seal sliding surface 7 side. The rigidity of A2 can be made higher than the rigidity of the first region A1. In addition, you may employ | adopt the reinforcement part 21 with the reinforcement part which concerns on 1st embodiment.

  In the first and second embodiments described above, the rigidity of the second region is increased by the reinforcing portion, but it is also possible to increase the rigidity of the second region by curing the rubber material. A third embodiment as an example is shown in FIGS.

  The second region A2 of the seal lip 30 according to the third embodiment includes a cured portion 31 made of a rubber material that is cured as compared to the rubber material 9 that forms the first region A1 (the cured portion 31 is , Shown in black in the figure). After molding the seal lip with the rubber material 9, the rubber material 9 can be cured by subjecting the rubber material 9 to appropriate curing processing such as heat, light irradiation, and chemical treatment. The curing process is performed only on the rubber material 9 that forms the second region A2, and is not performed on the rubber material 9 that forms the first region A1. Since the hardened portion 31 is harder than the rubber material 9 in the first region A1 that has not been hardened, the hardened portion 31 has excellent resistance to the pressing force of the seal lip 30. For this reason, 3rd embodiment can make the rigidity of 2nd area | region A2 containing the hardening part 31 higher than the rigidity of 1st area | region A1.

  Note that the illustrated hardened portion 31 is limited to the surface layer of the portion 12a ′ and the reinforcing portion 13 ′ between the solid projections 11 of the second region A2, but is necessary to keep the gap 14 appropriately. As long as the rigidity of the second region A2 can be obtained, the formation position and range of the hardened portion may be appropriately changed. For example, hardening all the rubber materials which form a solid part and a reinforcement part, abbreviate | omitting a reinforcement part, hardening only the solid part of a 2nd area | region, and hardening only a reinforcement part are mentioned.

  A fourth embodiment is shown in FIGS. The fourth embodiment is an example in which the second means is employed, and differs from the first embodiment in that the reinforcing portion is omitted and the inner diameter of the cored bar is changed.

  In FIG. 9, the radius near the seal lip 41 in a state before the seal member 40 according to the fourth embodiment is attached to the outer ring (corresponding to a natural state in which the seal member 40 is not deformed from the shape at the time of manufacture by an external force). An outer shape in the vicinity of the seal lip 41 when a cross section along the direction (corresponding to a cross section taken along line III-III in FIG. 1) is viewed is indicated by a two-dot chain line. The two-dot chain line seal member 40 in FIG. 9 is arranged coaxially with the counterpart member 2. The cross section along the radial direction of the seal member 40 corresponds to a cut surface on a virtual axial plane having the central axis of the seal member 40 as one side. Further, in FIG. 9, a cross section along the radial direction in the vicinity of the seal lip 41 in a state after the seal member 40 is attached to the outer ring (a state in which the seal member 40 is arranged with respect to the counterpart member 2) is indicated by a solid line. The seal member 40 has a cross-sectional structure illustrated in the entire circumferential direction. FIG. 10 is a side view of the vicinity of the seal lip 41 shown by a solid line in FIG.

  As is apparent from a comparison between the two-dot chain line seal lip 41 shown in FIG. 9 and the seal sliding surface 7 of the mating member 2, there is no seal sliding between the seal sliding surface 7 and the seal lip 41. The tightening margin is set in a direction perpendicular to the moving surface 7. When the two-dot chain line seal member 40 is moved to the left in the drawing and attached to the outer ring (see FIG. 2), the seal lip 41 is pressed against the seal sliding surface 7 by tightening allowance. For this reason, the seal lip 41 is elastically deformed so as to be bent, and is in a state indicated by a solid line in FIG. 9, and generates a force (tightening force) for pressing the seal sliding surface 7 in the radial direction.

  Now, the state before attachment in which the seal member 40 is arranged with respect to the mating member 2 (the state indicated by the two-dot chain line in FIG. 9) and the seal member 40 are arranged with respect to the mating member 2 Considering a comparison with the state after installation (indicated by a solid line in FIG. 9), an arbitrary cross section along the radial direction of the seal member 40 is formed in a direction perpendicular to the seal sliding surface 7 (radial direction). ) And a second cross-sectional area A4 that is not substantially displaced in the perpendicular direction (radial direction). The radius at each part of the seal lip 41 in the first cross-sectional area A3 increases as compared to before the mounting due to the radial displacement accompanying the aforementioned bending deformation, and is larger after the mounting. The amount of displacement in the radial direction (increase in radius) decreases as the distance from the tip of the seal lip 41 having the largest tightening margin (the lowest part of the seal lip 41 in the two-dot chain line in FIG. 9) increases. At the boundary between the first cross-sectional area A3 and the second cross-sectional area A4, there is almost no displacement in the radial direction, and no deformation that affects the tension force occurs.

  That is, the first cross-sectional area A3 that is displaced in a direction that is substantially perpendicular to the seal sliding surface 7 is that the seal lip 41 is tightened when the seal member 40 is disposed in a predetermined manner with respect to the counterpart member 2. It refers to an elastically deformed portion of the seal member 40 that is displaced in the direction perpendicular to the seal lip 41 by being pressed against the seal sliding surface 7 in an amount that affects the tightening force of the seal lip 41. On the other hand, the second cross-sectional area A4 that is not displaced in a direction substantially perpendicular to the seal sliding surface 7 is that when the seal member 40 is arranged with respect to the mating member 2, the seal lip 41 is tightened. The non-elasticity of the seal member 40 that is not displaced in the perpendicular direction by being pressed against the seal sliding surface 7 or that is displaced in the perpendicular direction by an amount that can dynamically ignore the influence on the tight force of the seal lip 41. It refers to the deformed part.

  In FIG. 9, the boundary between the first cross-sectional area A3 and the second cross-sectional area A4 is the left and right in the figure in contact with the arrow line indicating the range of the first cross-sectional area A3 and the arrow line indicating the range of the second cross-sectional area A4. 10 is an extension of the circumferential lead line in FIG. 10 and is in contact with the arrow line indicating the range of the first cross-sectional area A3 and the arrow line indicating the range of the second cross-sectional area A4. It is in.

  As shown in FIG. 9, the first cross-sectional area A <b> 3 includes a seal lip 41. The second cross-sectional area A4 is composed of a core metal 42 and a portion other than the seal lip 41 of the rubber material 43. As shown in FIGS. 9 and 10, the cored bar 42 has an edge 42 a that is disposed at the boundary with the first cross-sectional area A <b> 3 in the second cross-sectional area A <b> 4. The rigidity at the boundary portion of the second cross-sectional area A4 is higher than the rigidity of the seal lip 41 in the first cross-sectional area A3 by the cored bar 42 arranged only in the second cross-sectional area A4. . For this reason, the rigidity in the part which supports this solid part is improving compared with the solid part which continues the circumferential direction whole periphery so that the some protrusion 11 may be connected among the seal lips 41. FIG. Thereby, in the solid part of the seal lip 41, the amount of elastic deformation due to the above-mentioned pressing force is reduced in the portion 41a extending between the protrusions 11 adjacent in the circumferential direction. That is, the edge of the metal core does not reach the boundary of the second cross-sectional area A4, and in the example shown in FIG. Is suppressed. By increasing the rigidity at the boundary portion of the second cross-sectional area A4, the size of the gap 14 in the direction perpendicular to the seal sliding surface 7 is secured to a predetermined ratio or more with respect to the height of the protrusion 11. . The tightness of the seal lip 41 is not increased by the cored bar 42 that exists only in the second cross-sectional area A4.

  Thus, in the oil seal according to the fourth embodiment, the rigidity of the seal lip 41 in the first cross-sectional area A3 is the rigidity at the boundary with the first cross-sectional area A3 in the second cross-sectional area A4 of the seal member 40. Since it is higher than the rigidity, the elastic deformation at the portion 41a between the protrusions 11 of the seal lip 41 is suppressed (see FIG. 10). Thereby, this oil seal can suppress elastic deformation in the portion 41 a extending between the protrusions 11 without increasing the number of protrusions of the seal lip 41. Therefore, this oil seal effectively reduces the sealing torque between each protrusion 11 and the seal sliding surface 7 by fluid lubrication by reducing the radius R of the protrusions 11, the number of protrusions, and the interval P between the protrusions 11. On the other hand, the gap 14 is kept in an appropriate size between the portion 41a between the projections 11 of the seal lip 41 and the seal sliding surface 7 without allowing direct contact, and the portion 41a between the projections 11 and the seal lip 41 is sealed. The seal torque due to the shearing of the lubricating oil with the sliding surface 7 can also be effectively reduced, and the seal torque can be further reduced.

  Further, in this oil seal, since the edge 42a of the annular cored bar 42 is disposed at the boundary of the second cross-sectional area A4, the boundary of the second cross-sectional area A4 is formed by the cored bar 42 serving as the skeleton of the seal member 40. The rigidity at the part can be increased.

  High rigidity at the boundary portion of the second cross-sectional area may be achieved by adding a member different from the core metal. FIG. 11 shows a fifth embodiment as an example.

  The seal member 50 according to the fifth embodiment includes an annular cored bar 51 formed of a metal plate and a reinforcing ring 53 formed of a material having higher rigidity than the rigidity of the rubber material 52. The seal member 50 has a cross-sectional structure illustrated in the entire circumferential direction. The metal core 51 is shorter in the radial direction than the first embodiment, and the seal lip 54 is longer correspondingly. The boundary between the first cross-sectional area A3 and the second cross-sectional area A4 is in the middle of the seal lip 54. The cored bar 51 is located at a distance from the boundary portion of the second cross-sectional area A4. The seal lip 54 has a thin portion in the second cross-sectional area A4 that gradually becomes thinner from the portion 54a located in the first cross-sectional area A3 toward the core metal 51, and gradually becomes thicker from the thin wall portion toward the core metal 51. And a cored bar adhering portion.

  The reinforcing ring 53 is made of an annular metal wire and has a circular cross section. The reinforcement ring 53 is arrange | positioned in the boundary part with 1st cross-section area | region A3 among 2nd cross-section area | region A4.

  The rigidity at the boundary portion of the second cross-sectional area A4 is higher than the rigidity of the portion 54a of the seal lip 54 in the first cross-sectional area A3 due to the reinforcing ring 53 disposed only in the second cross-sectional area A4. ing. For this reason, the rigidity in the part which supports the solid part of the seal lip 54 is improved. Thereby, the elastic deformation amount by the above-mentioned tight force is reducing in the part between the protrusions 11 of the seal lip 54. That is, as compared with the case where the reinforcing ring 53 is replaced with a rubber material, the elastic deformation of the portion extending between the protrusions 11 is suppressed. The reinforcing ring 53 existing only in the second cross-sectional area A4 does not increase the tightening force of the seal lip 54.

  Thus, the oil seal according to the fifth embodiment can increase the rigidity at the boundary portion of the second cross-sectional area A4 of the seal member 50 by the reinforcing ring 53.

  In addition, since the oil seal can reduce the rigidity by reducing the thickness of the seal lip 54 connecting the core metal 51 and the reinforcing ring 53, the reinforcing ring 53 is in accordance with the eccentricity of the counterpart member 2. Are also eccentric, and the followability of the seal lip 54 is improved when the eccentricity is large.

  The bearing with seal according to each of the above-described embodiments can be employed as a rolling bearing that supports a rotating shaft of an automobile transmission. An example is shown in FIG. The illustrated transmission is a multi-stage transmission that changes the gear ratio stepwise, and the above-described embodiment is used as a bearing B with a seal that rotatably supports the rotation shaft (for example, the input shaft S1 and the output shaft S2). It has one that falls under either. The illustrated transmission includes an input shaft S1 to which engine rotation is input, an output shaft S2 provided in parallel with the input shaft S1, and a plurality of gear trains G1 to G4 that transmit the rotation from the input shaft S1 to the output shaft S2. Each of the gear trains G1 to G4 and a clutch (not shown) incorporated between the input shaft S1 or the output shaft S2, and the gear trains G1 to G4 used by selectively engaging the clutches. This changes the speed ratio of the rotation transmitted from the input shaft S1 to the output shaft S2. The rotation of the output shaft S2 is output to the output gear G5, and the rotation of the output gear G5 is transmitted to a differential gear or the like. The input shaft S1 and the output shaft S2 are rotatably supported by a bearing B with a seal, respectively. In addition, this transmission is provided with each seal by splashing or spraying the lubricant oil by splashing the lubricant oil accompanying the rotation of the gear or by spraying the lubricant oil from the nozzle provided in the housing H. It is applied to the side surface of the bearing B.

  In the above-described embodiment, the inner ring rotating type bearing has been described as an example. However, the present invention is applied to an outer ring rotating type bearing (a bearing in which the seal member is fixed to the inner ring and the counterpart member is on the outer ring side). It is also possible.

  Further, in the above-described embodiment, the description has been given by taking as an example a type of bearing that uses balls as rolling elements, but the present invention may be applied to a type of bearing that uses cylindrical rollers or tapered rollers as rolling elements. Good.

  Moreover, although the above-mentioned embodiment demonstrated the example which provided the sealing member in the both sides of the bearing internal space, you may make it provide a sealing member only in the one side of a bearing internal space.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. Accordingly, the scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1, 40, 50 Seal member 2 Mating member 3 Bearing inner space 4 Outer ring 5 Rolling element 7 Seal sliding surface 8, 42, 51 Core metal 9, 43, 52 Rubber material 10, 20, 30, 41, 54 Seal lip 11 Protrusion 12 Solid part 12a, 12a 'Part 13, 13', 21 Reinforcement part 14 Clearance 31 Curing part 42a Edge part 53 Reinforcement ring A1 First area A2 Second area A3 First section area A4 Second section area B With seal Bearing S1 input shaft (rotary shaft)
S2 Output shaft (rotary shaft)

Claims (9)

A seal member having a seal lip formed of a rubber material; and a mating member that rotates relative to the seal member in a circumferential direction. A seal sliding surface formed on the mating member; and the seal lip In an oil seal in which a tightening margin is set, and the seal lip has a plurality of protrusions in sliding contact with the seal sliding surface in a fluid lubrication state at predetermined intervals in the circumferential direction.
Considering the seal lip in the circumferential direction by the presence or absence of the projection, when the region where the projection is present in the seal lip is the first region, and the region where the projection is not present is the second region, An oil seal characterized in that the rigidity of the second region is higher than the rigidity of the first region.   The said 2nd area | region of the said seal lip has the reinforcement part formed largely in the direction in alignment with the said seal sliding surface or the direction away from the said seal sliding surface compared with the said 1st area | region. Oil seal.   The seal lip has a solid portion that is continuous in the entire circumferential direction so as to connect the plurality of protrusions, and the reinforcing portion is a portion of the solid portion that extends between the protrusions adjacent in the circumferential direction. The oil seal according to claim 2, which is continuous only with the oil.   The said 2nd area | region of the said seal lip has a hardening part which consists of the said rubber material in the state hardened compared with the said rubber material which forms said 1st area | region. Oil seal as described. A seal member having a seal lip formed of a rubber material; and a mating member that rotates relative to the seal member in a circumferential direction. A seal sliding surface formed on the mating member; and the seal lip In an oil seal in which a tightening margin is set, and the seal lip has a plurality of protrusions in sliding contact with the seal sliding surface in a fluid lubrication state at predetermined intervals in the circumferential direction.
Considering a comparison of the state before and after the seal member is arranged with respect to the mating member, an arbitrary cross section along the radial direction of the seal member is perpendicular to the seal sliding surface. When divided into a first cross-sectional area that is substantially displaced in the direction and a second cross-sectional area that is not substantially displaced in the perpendicular direction, a boundary between the second cross-sectional area and the first cross-sectional area The oil seal is characterized in that its rigidity is higher than that of the first cross-sectional area. The seal member has an annular cored bar formed of a metal plate,
The oil seal according to claim 5, wherein the metal core has an edge portion arranged at the boundary portion. The seal member includes an annular cored bar formed of a metal plate, and a reinforcing ring formed of a material having high rigidity compared to the rigidity of the rubber material,
The oil seal according to claim 5, wherein the reinforcing ring is disposed at the boundary portion.   A bearing with a seal, comprising the oil seal according to any one of claims 1 to 7, wherein the seal member separates the bearing internal space from the outside.   The bearing with a seal according to claim 8 which supports a rotating shaft of a transmission of an automobile.

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