JP7323780B2 - Seal and bearing device - Google Patents

Description

The present disclosure relates to seals and bearing devices using the same.

In the ironmaking process, iron ores and coke are charged into a blast furnace and chemically reacted at high temperatures to produce pig iron. Sintered ore obtained by agglomerating fine ore is conventionally used as the iron ore to be charged into the blast furnace, since the blast furnace is clogged if the fine ore is charged into the blast furnace as it is. The sintered ore is produced by granulating a blended material composed of ore fines, limestone, coke fines, etc. to produce a sintering raw material, and then sintering the sintering raw material.

A Dwight Lloyd (DL) type sintering machine is widely used for the production of sintered ore. A DL type sintering machine includes a plurality of pallet trucks, an ignition furnace, and a wind box group. The pallet truck travels on the track from the ore supply section to which the raw material for sintering is supplied to the ore discharge section to which the sintered ore is discharged. The ignition furnace ignites the surface of the raw material for sintering loaded onto the pallet truck. The windboxes are arranged below the pallet trucks that run from the feed station to the mine discharge station. The wind box group sucks air above the pallet trucks to promote combustion of coke in the sintering material.

Wheels of the pallet truck are rotatably supported on axles. In order to ensure stable running of the pallet truck, it is important to manage the bearings interposed between the wheels and axles. If the bearing fails and the smooth rolling motion of the rolling elements is impaired, the pallet truck cannot run stably on the track.

One of the causes of bearing failure is the intrusion of dust into the bearing space where the rolling elements are arranged. Specifically, when dust enters the bearing space, the dust contaminates the lubricant filled in the bearing space. The dust particles dispersed in the lubricant damage and wear the rolling elements in the bearing space and the raceway surfaces of the outer and inner rings.

In order to prevent failure of the bearing, it is conceivable to increase the frequency of supplying lubricant to the bearing space. By supplying lubricant to the bearing space, the dirty lubricant in the bearing space is pushed out and replaced with new lubricant, so the lubricant that contacts the rolling elements, outer ring, and inner ring is cleaned. A known automatic lubrication device can be used to supply the lubricant. However, for example, due to meandering of the pallet truck or wear of the wheels, the connection between the greasing port of the pallet truck and the nozzle of the automatic lubricator may become unstable. Therefore, even when an automatic lubricator is used, an operator manually performs greasing work periodically in order to ensure reliability of greasing. Manual greasing work is very difficult because it is performed while the sintering machine is in operation, that is, while the pallet truck is running.

In order to prevent failure of the bearing, it is conceivable to devise a seal for sealing the bearing space.

For example, Patent Literature 1 discloses a circular ring including a first slinger arranged on the outer ring side, a second slinger arranged on the inner ring side, and an elastic body arranged between the first slinger and the second slinger. An annular seal is disclosed. The first and second slingers each have an L-shaped cross section and are arranged such that their ends are adjacent to each other. The elastic body is fixed to the first slinger and slidably contacts the second slinger with a plurality of lips. The elastic body has an annular facing surface in the vicinity of the opening formed between the end of the first slinger and the end of the second slinger. The annular facing surface faces the second slinger with a small gap therebetween. An annular rib extending in the circumferential direction and a plurality of radial ribs extending radially outward from the annular rib are formed on the annular facing surface.

According to Patent Document 1, dust entering the seal through the opening enters between the second slinger and the annular opposing surface, but is prevented from further entering by the annular rib. The dust blocked by the annular ribs is pushed toward the opening by the radial ribs and discharged to the outside through the opening.

Patent Literature 2 discloses an oil seal used in automobile-related equipment and the like. This oil seal has a main lip for preventing oil from leaking to the outside of the equipment and a dust lip for preventing dust from entering the inside of the equipment. Each of the main lip and the dust lip includes an inner slanted surface provided on the inner side of the device and an outer slanted surface provided on the outer side of the device. close to the axis. The outer slope of the main lip is provided with a helical projection or recess.

According to Patent Document 2, when the shaft of the device rotates, the protrusions or recesses provided on the outer slope of the main lip exert a pumping action to generate an air flow. This airflow pushes dust back out of the equipment in the space defined by the inner bevel of the dust lip, the outer bevel of the main lip, and the axis of the equipment. Therefore, even if dust passes through the lip end of the dust lip and enters the space, the dust is transported away from the lip end of the main lip. Therefore, dust is suppressed from reaching the lip end of the main lip and being bitten therein.

Patent Literature 3 also discloses an oil seal used in automobiles and the like. The oil seal has a main lip that contacts the machine shaft and a dust lip that does not contact the machine shaft. The main lip, like the main lip of the oil seal in Patent Document 2, contacts the shaft of the equipment at the linear lip end. The inner peripheral surface of the main lip is provided with a helical projection or groove from the lip end toward the dust lip side. The inner peripheral surface of the dust lip is provided with projections sloping in the opposite direction to the projections or grooves of the main lip.

According to Patent Document 3, when the shaft of the device rotates, the protrusion of the dust lip generates an air flow. Dust can be discharged. On the other hand, the protrusions or grooves in the main lip create an airflow that pushes back the oil trying to escape from the interior of the equipment.

JP 2012-251568 A JP 2014-9753 A Japanese Utility Model Laid-Open No. 6-73545

A seal that seals the bearing space is pressed against a member (rotating member) that rotates relative to the seal, out of the members on the outer ring side and the inner ring side. Theoretically, therefore, dust should not be able to enter the bearing space. In practice, however, the problem arises that dust passes through the seal and enters the bearing space.

For example, a film of lubricant is formed between the seal and the rotating member, and the seal is not in perfect contact with the rotating member. Therefore, dust smaller than the film thickness of the lubricant easily gets into the gap between the seal and the rotating member. In addition, relative rotation of the outer ring side member and the inner ring side member causes the seal to vibrate to the outside or the inside of the bearing space, or the gap between the seal and the rotating member to change. As a result, even dust slightly larger than the film thickness of the lubricant may get into the gap between the seal and the rotating member. When the edge of the contact surface of the seal with respect to the rotating member is worn and has a rounded shape, dust is more likely to enter the gap between the seal and the rotating member.

Once dust that is slightly larger than the film thickness of the lubricant gets into the gap between the seal and the rotating member, it stays in place due to the pressing force of the seal against the rotating member. When the seal vibrates again in this state, the dust trapped between the seal and the rotating member moves toward the bearing space. By repeating this, the dust reaches the end of the contact surface of the seal and finally enters the bearing space along with the flow of the lubricant.

The seal of Patent Document 1 dams up the dust with the annular rib before the dust reaches the lip that slides on the second slinger. However, the annular rib does not or only slightly contacts the second slinger and thus allows dust to easily pass through. Dust that slips through the annular rib may reach the lip immediately and enter between the lip and the second slinger. In that case, the dust stays in place due to the pressing force of the lip against the second slinger and cannot escape from between the lip and the second slinger. Dust trapped between the lip and the second slinger may move gradually due to vibration of the seal and enter the bearing space.

The oil seals of Patent Literatures 2 and 3 generate an air flow with a helical protrusion or the like to push back dust in front of the lip end of the main lip. However, it is also conceivable that some dust that could not be pushed back by the airflow reaches the lip edge of the main lip. Since the lip end of the main lip is in linear contact with the axis of the equipment, it allows dust to pass through relatively easily. Therefore, dust may enter the inside of the seal.

An object of the present disclosure is to provide a seal that can more reliably prevent dust from entering the bearing space, and a bearing device using the same.

A seal according to the present disclosure is an annular seal for use in a bearing device. The bearing device has an outer ring member and an inner ring member. The inner ring member is inserted into the outer ring member to form a bearing space together with the outer ring member. The outer ring member and the inner ring member are arranged coaxially and configured to relatively rotate about the axis. A seal is disposed between the outer ring member and the inner ring member to seal the bearing space. The seal is fixed to one of the outer ring member and the inner ring member. The seal includes an annular contact surface and a groove. The contact surface is pressed over the entire circumferential direction against the other member of the outer ring member and the inner ring member. A groove is formed in the contact surface. The groove opens at the outer peripheral edge, which is the peripheral edge farther from the bearing space, of the two peripheral edges of the contact surface.

According to the present disclosure, it is possible to more reliably prevent dust from entering the bearing space.

FIG. 1 is a longitudinal sectional view of a bearing device in which seals according to each embodiment are used. FIG. 2 is a vertical cross-sectional view of the seal according to the first embodiment. 3 is a front view of the seal shown in FIG. 2; FIG. FIG. 4 is a schematic diagram for explaining the behavior of dust when dust is caught between the contact surface and the rotating member in a general seal. FIG. 5 is a schematic diagram for explaining the behavior of dust when dust is caught between the contact surface and the rotating member in the seal shown in FIG. FIG. 6 is a vertical cross-sectional view of a seal according to the second embodiment. FIG. 7 is a vertical cross-sectional view of a seal according to the third embodiment.

A seal according to an embodiment is an annular seal used in a bearing device. The bearing device has an outer ring member and an inner ring member. The inner ring member is inserted into the outer ring member to form a bearing space together with the outer ring member. The outer ring member and the inner ring member are arranged coaxially and configured to relatively rotate about the axis. A seal is disposed between the outer ring member and the inner ring member to seal the bearing space. The seal is fixed to one of the outer ring member and the inner ring member. The seal includes an annular contact surface and a groove. The contact surface is pressed over the entire circumferential direction against the other member of the outer ring member and the inner ring member. A groove is formed in the contact surface. The groove opens at the outer peripheral edge, which is the peripheral edge farther from the bearing space, of the two peripheral edges of the contact surface (first configuration).

The seal according to the first configuration is fixed to one of the outer ring member and the inner ring member of the bearing device. This seal contacts the other of the outer ring member and the inner ring member, that is, a member (rotating member) that rotates relative to the seal at an annular contact surface. Since the contact surface is pressed against the rotating member over the entire circumferential direction, it is possible to prevent dust from entering the bearing space.

Further, according to the first configuration, the groove is formed in the contact surface. The groove opens at the outer peripheral edge of the annular contact surface, which is farther from the bearing space. Therefore, even if dust gets stuck between the contact surface of the seal and the rotating member due to vibration or the like, the dust is captured by the grooves on the contact surface while the seal and rotating member are relatively rotating. It can be discharged to the side opposite to the bearing space. Therefore, it is possible to more reliably prevent dust from entering the bearing space.

The groove preferably slopes rearward in the direction of rotation of the one member relative to the other member toward the outer periphery (second configuration).

When the rotary member rotates relative to the seal, it is conceivable that the airflow, centrifugal force, etc. generated by the rotation may contribute to the discharge of dust trapped in the grooves of the contact surface. However, when the seal and the rotating member rotate relatively at a low speed, the airflow, centrifugal force, etc. also decrease. Therefore, in the second configuration, the groove is formed so as to be inclined rearward in the direction of rotation of the rotating member toward the outer peripheral edge of the contact surface. As a result, the dust trapped in the groove naturally moves along the groove to the outer peripheral side of the contact surface as the rotary member rotates relative to the seal. Therefore, even when the seal and the rotating member rotate relatively at a low speed, it is possible to facilitate the discharge of dust trapped between the contact surface of the seal and the rotating member.

The groove is preferably formed on the contact surface in a range from the outer peripheral edge to half the width of the contact surface (third configuration).

According to the third configuration, the groove is formed only in the region far from the bearing space on the contact surface of the seal. Therefore, when dust is caught between the contact surface and the rotating member, the dust can be quickly discharged without unnecessarily approaching the bearing space through the groove.

A plurality of grooves may be formed in the contact surface at intervals in the circumferential direction (fourth configuration).

According to the fourth configuration, a plurality of grooves are formed in the contact surface of the seal. Therefore, for example, the seal may vibrate multiple times during one rotation of the rotating member with respect to the seal, and the dust trapped between the contact surface and the rotating member may move toward the bearing space multiple times. However, it is possible to catch the dust in one of the plurality of grooves at an early stage and discharge it. Therefore, it is possible to more reliably prevent dust from entering the bearing space.

A bearing device according to an embodiment includes an outer ring member, an inner ring member, and the seal. The inner ring member is inserted into the outer ring member to form a bearing space together with the outer ring member. The inner ring member is arranged coaxially with the outer ring member and rotates relative to the outer ring member around the axis.

Preferably, the bearing device further comprises an annular plate. The annular plate is fixed to one axial end face of the outer ring member and covers a gap between the outer ring member and the inner ring member. The seal is arranged axially between the annular plate and the bearing space.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding configurations are denoted by the same reference numerals, and the same description will not be repeated.

[First embodiment]
(bearing device)
FIG. 1 is a longitudinal sectional view of a bearing device 10. FIG. A longitudinal section refers to a section cut along a plane including the central axis X of the bearing device 10 . Since the longitudinal section of the bearing device 10 is symmetrical with respect to the central axis X, only a section on one side of the central axis X is shown in FIG. Hereinafter, the direction in which the central axis X extends will be referred to as the axial direction, and each direction perpendicular to the central axis X will be referred to as the radial direction. Also, the circumferential direction of a circle centered on the central axis X is simply referred to as the circumferential direction.

Referring to FIG. 1, a bearing device 10 is provided, for example, around the undercarriage of a pallet truck of a DL type sintering machine. Seals 20 a , 20 b , 20 c according to the present embodiment are attached to the bearing device 10 . The bearing device 10 includes an outer ring member 11 , an inner ring member 12 , a plurality of rolling elements 13 , a retainer 14 and an annular plate 15 .

The outer ring member 11 includes an outer ring 111 , wheels 112 and a cover 113 .

The outer ring 111 has a substantially cylindrical shape with the central axis X as the axis. The inner peripheral surface of the outer ring 111 is provided with raceway surfaces 1111 and 1112 on which the rolling elements 13 roll.

The wheel 112 has a substantially cylindrical shape with the central axis X as the axis. Wheel 112 is fixed to the outer peripheral surface of outer ring 111 . An annular recess 1121 is formed in one axial end face of the wheel 112 to accommodate the seal 20a. A cover 113 is attached to the other axial end face of the wheel 112 .

The cover 113 has a substantially cylindrical shape with the central axis X as the axis. The cover 113 has an annular recess 1131 on its inner peripheral surface to accommodate the seal 20b.

The inner ring member 12 is inserted into the outer ring member 11 to form a bearing space S together with the outer ring member 11 . The inner ring member 12 is arranged coaxially with the outer ring member 11 . In other words, the outer ring member 11 and the inner ring member 12 are arranged such that their axial centers substantially coincide with each other. The outer ring member 11 and the inner ring member 12 rotate about the central axis X relative to each other. For example, the inner ring member 12 can be fixed so as not to rotate in the bearing device 10, and the outer ring member 11 can be rotated around the central axis X. Alternatively, the outer ring member 11 may be non-rotatably fixed in the bearing device 10 and the inner ring member 12 may be rotated around the central axis X. In this embodiment, since the outer ring member 11 includes the wheel 112, the inner ring member 12 is fixed and the outer ring member 11 is rotated around the central axis X.

The inner ring member 12 includes an inner ring 121 , an axle 122 and a cover 123 .

The inner ring 121 is arranged inside the outer ring 111 . The inner ring 121 has a substantially cylindrical shape with the central axis X as the axis. Raceway surfaces 1211 and 1212 are provided on the outer peripheral surface of the inner ring 121 corresponding to the raceway surfaces 1111 and 1112 of the outer ring 111 .

Axle 122 extends axially. An inner ring 121 and a cover 123 are attached to the axial ends of the axle 122 . The inner ring 121 and the cover 123 are fixed to the outer peripheral surface of the axle 122 .

The cover 123 is arranged on the opposite side of the cover 113 with the wheel 112 interposed therebetween. Cover 123 includes a plate portion 1231 and a projecting portion 1232 . The plate portion 1231 is a substantially annular plate having the central axis X as its axis. Plate portion 1231 faces the end face of wheel 112 in which recess 1121 is formed. The protruding portion 1232 is provided on the inner peripheral portion of the plate portion 1231 and protrudes toward the inner ring 121 side. A seal 20 c is attached to the protruding portion 1232 .

An annular bearing space S is formed between the outer ring member 11 and the inner ring member 12 . In the bearing space S, the rolling elements 13 and the retainer 14 are arranged. The bearing space S is filled with a lubricant such as grease or oil.

A plurality of rolling elements 13 are arranged in the bearing space S in the circumferential direction. In this embodiment, two rows of rolling elements 13 are provided in the bearing space S. As shown in FIG. One row of rolling elements 13 rolls on the raceway surface 1111 of the outer ring 111 and the raceway surface 1211 of the inner ring 121 . The other row of rolling elements 13 rolls on the raceway surface 1112 of the outer ring 111 and the raceway surface 1212 of the inner ring 121 . The rolling elements 13 in each row are held at regular intervals by a retainer 14 . In the example of this embodiment, the rolling elements 13 are tapered rollers, but may be cylindrical rollers, balls, or the like.

The annular plate 15 is an annular plate having the central axis X as its axis. The annular plate 15 covers the gap G between the outer ring member 11 and the inner ring member 12 on one axial end side of the bearing device 10 . That is, the annular plate 15 is disposed across one axial end surface of the outer ring member 11 and one axial end surface of the inner ring member 12 . The annular plate 15 is fixed to one axial end face of the outer ring member 11 . In this embodiment, the annular plate 15 is fixed to the wheel 112 of the outer ring member 11 by fastening members 16 such as screws. The annular plate 15 is not fixed to one axial end surface of the inner ring member 12 , that is, to the cover 123 .

(sticker)
Annular seals 20 a , 20 b , 20 c are attached to the bearing device 10 . The seals 20a, 20c are arranged between the annular plate 15 and the bearing space S in the axial direction. The seal 20b is arranged on the opposite side of the seals 20a and 20c with the bearing space S interposed therebetween. In the example of this embodiment, the seals 20a, 20b, 20c are all elastic bodies. Various materials can be used for the seals 20a, 20b, and 20c. The material of the seals 20a, 20b, and 20c is, for example, natural rubber, nitrile rubber (NBR), fluororubber, synthetic rubber such as silicone rubber, or heat-resistant Teflon (registered trademark). However, the seals 20a, 20b, and 20c do not necessarily have to be entirely made of an elastic material. For example, in order to retain the seals 20a, 20b, 20c on the outer ring member 11 or the inner ring member 12, the seals 20a, 20b, 20c may be formed by embedding an annular metal member in an elastic body.

Each of the seals 20a, 20b, 20c is arranged between the outer ring member 11 and the inner ring member 12 to seal the bearing space S. Each of the seals 20, 20b, 20c is fixed to one member of the outer ring member 11 and the inner ring member 12, and is pressed against and contacts the other member of the outer ring member 11 and the inner ring member 12. As shown in FIG.

The seal 20a is fixed to the outer ring member 11 and pressed against the inner ring member 12 to make contact therewith. More specifically, the seal 20 a is accommodated in the recess 1121 of the wheel 112 of the outer ring member 11 and fitted to the radially inner annular wall surface of the recess 1121 . Seal 20 a is compressed between wheel 112 and cover 123 of inner ring member 12 . The seal 20 a is pressed against the plate portion 1231 of the cover 123 .

The seal 20b is also fixed to the outer ring member 11 and is pressed against and contacts the inner ring member 12 . More specifically, the seal 20b is accommodated and fixed in an annular recess 1131 in the cover 113 of the outer ring member 11 . Seal 20b is compressed between cover 113 and axle 122 of inner ring member 12 . Seal 20 b is pressed against the outer peripheral surface of axle 122 .

The seal 20c is arranged radially inside the seal 20a. Contrary to the seal 20a, the seal 20c is fixed to the inner ring member 12 and pressed against the outer ring member 11 to make contact therewith. More specifically, the seal 20c fits with the protrusion 1232 of the cover 123 on the inner ring member 12 . The seal 20 c is compressed between the plate portion 1231 of the cover 123 and the wheel 112 of the outer ring member 11 . Seal 20c is pressed against wheel 112 .

Next, the detailed structure of the seal 20c will be described with reference to FIG. FIG. 2 is a longitudinal sectional view of the seal 20c attached to the bearing device 10. FIG. The seal 20a (FIG. 1) has a configuration in which the seal 20c is horizontally inverted on the paper surface of FIG. The configuration of seal 20b (FIG. 1) is generally equivalent to the configuration of seal 20c rotated clockwise 90° on the page of FIG. Therefore, the detailed structural description of the seals 20a and 20b is omitted.

As shown in FIG. 2, seal 20c has an annular seal body 21 and lip 22, respectively. The seal 20c is a so-called V-ring. The seal 20 c has a pocket 23 having a substantially V-shaped cross section between the seal body 21 and the lip 22 . The seal body 21 is fitted to the projecting portion 1232 of the cover 123 of the inner ring member 12 . Lip 22 is integrally formed with seal body 21 . Lip 22 is connected to the inner periphery of seal body 21 .

The lip 22 prevents dust from entering the bearing space S and allows lubricant to be discharged from the bearing space S. As indicated by the two-dot chain line in FIG. 2, when the seal 20c is not attached to the bearing device 10, the lip 22 extends away from the seal body 21 as it goes radially outward. When the seal 20 c is attached to the bearing device 10 , the lip 22 is pressed against the wheel 112 of the outer ring member 11 . That is, the lip 22 contacts the outer ring member 11 at the contact surface 221 .

The contact surface 221 is an annular surface that is pressed against the outer ring member 11 over the entire circumferential direction. The contact surface 221 has a predetermined width W1 in the radial direction. The width W1 is, for example, 3 mm or more. The contact surface 221 has an outer perimeter 2211 and an inner perimeter 2212 . Of both peripheral edges of the annular contact surface 221 , the peripheral edge farther from the bearing space S is the outer peripheral edge 2211 , and the peripheral edge closer to the bearing space S is the inner peripheral edge 2212 . In the example of this embodiment, the contact surface 221 is an annular surface having a width W1 in the radial direction, so the outer peripheral edge 2211 is positioned radially outside the inner peripheral edge 2212 .

A groove 222 is formed in the contact surface 221 . Groove 222 opens into outer peripheral edge 2211 of contact surface 221 . Groove 222 extends toward an inner peripheral edge 2212 of contact surface 221 . However, groove 222 does not reach inner rim 2212 .

FIG. 3 is a view (front view) of the seal 20c viewed from the contact surface 221 side. Referring to FIG. 3 , in this example embodiment, seal 20 c has a plurality of grooves 222 . The grooves 222 are circumferentially spaced in the contact surface 221 of the seal 20c. However, the contact surface 221 may be provided with at least one groove 222 . Since the contact surface 221 presses into contact with the inner ring member 12 (FIG. 2) to prevent dust from entering the bearing space S, the number of the grooves 222 is preferably as small as possible. For example, the contact surface 221 is provided with four or less grooves 222 .

Each groove 222 is inclined with respect to the radial direction of the seal 20c. Each groove 222 slopes rearward in the direction of rotation R toward the outer peripheral edge 2211 of the contact surface 221 . That is, in each groove 222 , the open end 2221 that opens to the outer peripheral edge 2211 of the contact surface 221 is located behind the end 2222 on the opposite side in the rotational direction R. The direction of rotation R is the direction in which one of the outer ring member 11 and the inner ring member 12 (FIG. 2) to which the seal is fixed rotates relative to the other member. Regarding the seal 20c, the rotational direction R is the direction in which the outer ring member 11 rotates relative to the inner ring member 12 to which the seal 20c is fixed.

The groove 222 is formed on the contact surface 221 in a range from the outer peripheral edge 2211 to half the width W1. That is, when the contact surface 221 is bisected by an intermediate line L1 positioned between the outer peripheral edge 2211 and the inner peripheral edge 2212, the groove 222 is arranged so as to fit in the region 221a on the outer peripheral edge 2211 side. No groove 222 is formed in a region 221b on the inner peripheral edge 2212 side of the contact surface 221 . The area occupied by the grooves 222 on the contact surface 221 is small. For example, the area ratio of the grooves 222 to the entire contact surface 221 is preferably 2% or less.

[Effects of Embodiment]
The seal 20c according to this embodiment includes an annular contact surface 221 and a groove 222 formed in the contact surface 221. As shown in FIG. Since the contact surface 221 is pressed against the outer ring member 11 over the entire circumferential direction, entry of dust into the bearing space S can be prevented. On the other hand, the groove 222 opens onto the outer peripheral edge 2211 of the contact surface 221 . Therefore, even if dust enters between the contact surface 221 and the outer ring member 11, the groove 222 captures the dust while the outer ring member 11 is rotating with respect to the seal 20c. can be discharged to the side.

The mechanism by which dust is discharged by the grooves 222 will be specifically described with reference to FIGS. 4 and 5. FIG. FIG. 4 is for explaining the behavior of dust when dust is caught between a member (rotating member) that rotates relative to the seal 90 and the contact surface 921 in a general seal 90. It is a schematic diagram. FIG. 5 illustrates the behavior of dust when dust is caught between the contact surface 221 and a member (rotating member) that rotates relative to the seal 20c in the seal 20c according to this embodiment. It is a schematic diagram for.

First, referring to FIG. 4, when the rotating member rotates in the rotation direction R with respect to the seal 90, the seal 90 generates vibration with a minute amplitude as indicated by the two-dot chain line. When the contact surface 921 of the seal 90 vibrates to the opposite side (outside) of the bearing space S, or when the contact surface 921 separates from the rotating member due to vibration, the dust d near the outer peripheral edge 9211 of the contact surface 921 , are caught between the contact surface 921 and the rotating member. This dust d remains trapped between the contact surface 921 and the rotating member even when the contact surface 921 returns to its original position. When the contact surface 921 vibrates outward again in this state, the dust d further enters between the contact surface 921 and the rotating member. As this is repeated, the dust d reaches the inner peripheral edge 9212 of the contact surface 921 and enters the bearing space S through the inner peripheral edge 9212 . The dust d that has entered the bearing space S gets on the flow of the lubricant and contaminates the lubricant filled in the bearing space S as a whole.

On the other hand, as shown in FIG. 5, in the seal 20c according to the present embodiment, the dust d caught between the contact surface 221 and the rotating member is displaced in the rotating direction R of the rotating member with respect to the seal 20c. While rotating, it is captured in groove 222 . The dust d is guided by the groove 222 extending rearward in the rotational direction R and discharged from the open end 2221 on the outer peripheral edge 2211 side. Therefore, according to the seal 20c according to the present embodiment, even if dust is caught between the contact surface 221 and the rotating member, it is possible to promote the discharge of the dust, and the dust can be discharged into the bearing space S. Intrusion can be prevented more reliably.

In this embodiment, the groove 222 is inclined rearward in the direction of rotation R of the outer ring member 11 with respect to the seal 20c and the inner ring member 12 toward the outer peripheral edge 2211 of the contact surface 221 . By doing so, even if the relative rotation speed of the outer ring member 11 with respect to the inner ring member 12 is low, for example, about 3 to 6 rpm, the dust in the groove 222 can be guided toward the outer peripheral edge 2211 and discharged. can. However, when the relative rotational speed of the outer ring member 11 with respect to the inner ring member 12 is high, the groove 222 may be provided so as to extend along the normal to the rotation direction R without being inclined. This is because, when the relative rotational speed is high, the contribution of airflow and centrifugal force to the discharge of dust in the grooves 222 can be expected.

In this embodiment, the groove 222 is formed on the contact surface 221 in a range from the outer peripheral edge 2211 to half the width W1. As a result, the dust trapped in the groove 222 can be discharged without approaching the bearing space S unnecessarily.

In this embodiment, a plurality of grooves 222 are formed in the contact surface 221 at intervals in the circumferential direction. As a result, for example, during one rotation of the outer ring member 11 with respect to the seal 20c, the seal 20c vibrates a plurality of times, and the dust trapped between the contact surface 221 and the outer ring member 11 moves a plurality of times. Even in this case, it is possible to catch this dust in any of the grooves 222 at an early stage and discharge it. Therefore, dust can be prevented from entering the bearing space S more reliably.

For example, when the bearing device 10 that has been used under high temperature is cooled, the lubricant in the bearing space S shrinks in volume, and the dust existing between the contact surface 221 and the outer ring member 11 is removed together with the lubricant. There is a possibility of being drawn into the space S. However, in this embodiment, the groove 222 allows the dust between the contact surface 221 and the outer ring member 11 to be discharged at all times. Therefore, even if the bearing device 10 is cooled and volumetric contraction of the lubricant occurs, little or a small amount of dust is drawn into the bearing space S from between the contact surface 221 and the outer ring member 11 . Therefore, contamination of the lubricant in the bearing space S by dust can be prevented.

When the lubricant in the bearing space S passes through the seals 20a and 20c and is discharged to the outside of the bearing device 10 through the gap G between the outer ring member 11 and the inner ring member 12, the lubricant forms lumps and attracts dust. I have something to do. If the lubricant that has absorbed dust exists in the vicinity of the gap G, the dust may enter the bearing device 10 through this gap G. In contrast, in the present embodiment, an annular plate 15 is fixed to one axial end face of the outer ring member 11 and the gap G is covered by the annular plate 15 . Therefore, the lubricant that has adsorbed the dust cannot approach the gap G. Therefore, it is possible to prevent dust from entering the bearing device 10 through the gap G.

The inner peripheral side of the annular plate 15 covering the gap G is not fixed to the inner ring member 12 . Therefore, when new lubricant is supplied to the bearing space S and old lubricant is pushed out from the bearing space S, the old lubricant can be discharged from the inner peripheral side of the annular plate 15 to the outside of the bearing device 10. .

[Second embodiment]
A seal 30 according to the second embodiment will be described with reference to FIG. FIG. 6 is a longitudinal sectional view of the seal 30 attached to the bearing device 10 shown in FIG.

As shown in FIG. 6, the seal 30 has a configuration in which the seal 20c (FIG. 2) according to the first embodiment is rotated 90 degrees counterclockwise on the plane of the paper. However, the seal 30 is different from the seal 20c according to the first embodiment in that the contact surface 321 of the seal 30 contacts the outer ring member 11 in addition to the contact surface 221 thereof.

The contact surface 221 is an annular surface that is pressed against the outer ring member 11 over the entire circumferential direction. In this embodiment, the contact surface 221 has a predetermined width W1 in the axial direction. Therefore, the outer peripheral edge 2211 and the inner peripheral edge 2212 of the contact surface 221 are aligned in the axial direction.

Like the contact surface 221, the contact surface 321 is also an annular surface that is pressed against the outer ring member 11 over the entire circumferential direction. However, the contact surface 321 has a predetermined width W2 in the radial direction. The width W2 is, for example, 3 mm or more. At least one groove 322 is formed in the contact surface 321 . The groove 322 opens at the outer peripheral edge 3211 farther from the bearing space S out of the peripheral edges 3211 and 3212 of the contact surface 321 . The configuration of the groove 322 is similar to that of the groove 222 of the contact surface 221 .

In the seal 30 according to this embodiment, the contact surface 221 is arranged farther from the bearing space S than in the seal 20c according to the first embodiment. Therefore, the dust can be discharged by the groove 222 at a position farther from the bearing space S. Furthermore, the seal 30 according to this embodiment has a second contact surface 321 on the bearing space S side of the contact surface 221 . Therefore, even if dust passes through the first contact surface 221 , the dust can be prevented from entering the bearing space S by the second contact surface 321 . Further, since the grooves 322 are formed on the contact surface 321 in the same manner as the contact surface 221, even if dust enters between the contact surface 321 and the outer ring member 11, the grooves 322 close the bearing space S. Dust can be discharged to the opposite side.

[Third embodiment]
A seal 40 according to the third embodiment will be described with reference to FIG. FIG. 7 is a longitudinal sectional view of the seal 40 attached to the bearing device 10 shown in FIG.

As shown in FIG. 7, the seal 40 also has contact surfaces 221 and grooves 222, similar to the first and second embodiments. However, while the seal 20c (FIG. 2) according to the first embodiment and the seal 30 (FIG. 6) according to the second embodiment are V-rings having a substantially V-shaped cross section, the seal 40 has a substantially rectangular shape. has a cross section of

In seal 20c (FIG. 2) and seal 30 (FIG. 6), which are V-rings, there is a pocket 23 between the seal body 21 and the lip 22. FIG. Dust discharged from between the contact surface 221 and the outer ring member 11 due to the function of the groove 222 and old lubricant pushed out from the bearing space S tend to stay in the pocket 23 . As the deterioration of the lubricant remaining in the pocket 23 progresses, the operation of the lip 22 deteriorates.

On the other hand, as shown in FIG. 7, the seal 40 according to the present embodiment does not have pockets, so dust and lubricant do not accumulate. Also, since the seal 40 has a stronger pressing force against the outer ring member 11 than the V-ring, dust is less likely to get caught between the contact surface 221 and the outer ring member 11 . However, the V-ring is easier to adjust the contact pressure of the contact surface 221 with respect to the outer ring member 11 and is advantageous in terms of ease of assembly to the bearing device 10 . In order to improve assemblability, it is preferable to perform lightening processing on the portion of the seal 40 closer to the bearing space S than the contact surface 221 .

Although the embodiments according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present disclosure.

For example, the seals 20 c , 30 , 40 according to the above embodiment are fixed to the inner ring member 12 , but may be fixed to the outer ring member 11 . When the seals 20c, 30, 40 are fixed to the outer ring member 11, the contact surfaces 221, 321 are pressed against the inner ring member 12 and come into contact therewith.

In the above embodiments, the bearing device 10 in which the seals 20c, 30, 40 are used is a rolling bearing device. However, the seals 20c, 30, 40 may also be used in plain bearing devices. Seals according to the present disclosure can be used in a variety of bearing assemblies, not just those in pallet trucks of DL sintering machines.

In the bearing device 10 according to the above embodiment, the annular plate 15 is fixed to the outer ring member 11 that rotates around the central axis X. As shown in FIG. Even if the outer ring member 11 is fixed and the inner ring member 12 rotates around the central axis X, the centrifugal force acts radially outward, so the annular plate 15 is fixed to the outer ring member 11 . However, the annular plate 15 may be attached to the inner ring member 12 if it is desired to actively discharge the lubricant inside the bearing device 10 . Note that the bearing device 10 may not include the annular plate 15 .

10: Bearing device 11: Outer ring member 12: Inner ring member 15: Annular plate S: Bearing space 20a, 20b, 20c, 30, 40: Seal 221, 321: Contact surface 2211, 3211: Outer peripheral edge 2212, 3212: Inner peripheral edge 222 , 322: groove

Claims (5)

and an inner ring member that is inserted into the outer ring member and forms a bearing space together with the outer ring member. An annular seal for use in a bearing arrangement comprising
The said seal is
disposed between the outer ring member and the inner ring member to seal the bearing space;
fixed to one of the outer ring member and the inner ring member;
and an annular contact surface that is pressed against the other of the outer ring member and the inner ring member along the entire circumferential direction, and an annular contact surface that is formed on the contact surface and extends farther from the bearing space than both peripheral edges of the contact surface. a groove that opens to the outer peripheral edge, which is the peripheral edge, and does not open to the inner peripheral edge, which is the peripheral edge closer to the bearing space of the two peripheral edges ,
The seal, wherein the groove slopes rearward in a direction of rotation of the other member relative to the one member as it approaches the outer periphery . and an inner ring member that is inserted into the outer ring member and forms a bearing space together with the outer ring member. An annular seal for use in a bearing arrangement comprising
The said seal is
disposed between the outer ring member and the inner ring member to seal the bearing space;
fixed to one of the outer ring member and the inner ring member;
and an annular contact surface that is pressed against the other of the outer ring member and the inner ring member along the entire circumferential direction, and an annular contact surface that is formed on the contact surface and extends farther from the bearing space than both peripheral edges of the contact surface. a groove that opens to the outer peripheral edge, which is the peripheral edge, and does not open to the inner peripheral edge, which is the peripheral edge closer to the bearing space of the two peripheral edges,
A seal, wherein a plurality of said grooves are formed in said contact surface at intervals in said circumferential direction. A seal according to claim 1 or 2,
The seal, wherein the groove is formed in the contact surface from the outer periphery to half the width of the contact surface. an outer ring member;
an inner ring member that is inserted into the outer ring member to form a bearing space together with the outer ring member, is arranged coaxially with the outer ring member, and rotates relative to the outer ring member around an axis;
A seal according to any one of claims 1 to 3 ;
A bearing device. A bearing device according to claim 4 ,
further comprising an annular plate fixed to one axial end surface of the outer ring member and covering a gap between the outer ring member and the inner ring member;
A bearing device, wherein the seal is arranged between the annular plate and the bearing space in the axial direction.

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