JP2012207689A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen a greasing interval of lubricating oil, by preventing the inside lubricating oil from leaking to the outside, by preventing intrusion of foreign matter from the outside.SOLUTION: A floating seal 31 constituted of an annular seal body 32 and an O ring 33 is arranged between respective seal storage grooves 22B of a boss member 22 and end surfaces 24B and 25B of bracket members 24 and 25 on the outer peripheral side of a connecting pin 26. The annular seal body 32 has an annular sliding contact surface part 32D for sealing between the bracket members 24 and 25 by slidingly contacting with the end surfaces 24B and 25B of the bracket members 24 and 25, and an annular concave surface part 32E formed on the opposite side in the axial direction to the annular sliding contact surface part 32D and holding the O ring 33 in an elastically deforming state with the seal storage grooves 22B of the boss member 22.

Description

  The present invention relates to a bearing device that is suitably used for a pin coupling portion of a working device in a construction machine such as a hydraulic excavator.

  In general, a construction machine such as a hydraulic excavator has a configuration in which a bearing device is provided to rotatably connect a boom, an arm, a bucket, and the like that constitute a working front portion. Further, the boom cylinder, the arm cylinder, and the bucket cylinder that drive these boom, arm, and bucket are also configured to be rotatably connected using a bearing device.

  This type of prior art bearing device includes a boss member provided on one member of the boom, arm, bucket, and each cylinder, and a bush fitted on the inner peripheral side, and left and right sides of the boss member. A pair of bracket members serving as counterpart members arranged on both sides, a connecting pin for rotatably connecting the boss member between the bracket members, and an axially opposite end of the bush connected to the boss member It is comprised by the sealing means provided between the pins (for example, refer patent document 1).

JP 2004-28203 A

  By the way, in the above-described prior art bearing device, the sealing means is constituted by a dust seal, and the lip portion of the dust seal prevents foreign matters from entering from the outside in the axial direction of the connecting pin toward the inside. It is formed in an inclined shape. For this reason, the sealing means composed of the dust seal is effective in suppressing the entry of foreign matter, but does not function as an oil seal that prevents the internal lubricating oil from leaking to the outside, and the long distance between the bush and the connecting pin is long. There is a problem that it is difficult to keep in a lubricated state.

  That is, in the prior art bearing device, the boss member and the bracket member are smoothly rotated via the connecting pin. Lubricating oil is supplied from the outside so that the lubricating state is always maintained between the two. However, the lubricating oil supplied between the bush and the connecting pin is liable to leak to the outside from the lip portion of the dust seal because the viscosity decreases due to frictional heat or the like when the connecting pin slides in the bush. There is a problem that the lubrication interval of the lubricating oil is shortened.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to prevent foreign matter from entering between the bush and the connecting pin and to provide lubrication supplied between the two. An object of the present invention is to provide a bearing device capable of preventing oil from leaking to the outside and increasing the lubrication interval of the lubricating oil.

  In order to solve the above-described problems, the present invention includes a boss member provided with a bush fitted on an inner peripheral side, and a boss member that is inserted into the inner peripheral side of the bush and is pivotally connected to a counterpart member. The present invention is applied to a bearing device that includes a connecting pin that is provided on the both ends in the axial direction of the bush and a sealing means that is provided between the boss member and the connecting pin.

  The feature of the configuration adopted by the invention of claim 1 is that the sealing means is constituted by a floating seal that seals in a floating state between an end surface of the boss member and an end surface of the counterpart member that are opposed to each other in the axial direction. The floating seal is inserted into the outer peripheral side of the connecting pin and is slidably contacted with an end surface of the counterpart member to seal between the counterpart member, and between the annular seal body and the boss member. And an O-ring that is arranged in an elastically deformed state between the annular seal body and the boss member and elastically biases the annular seal body toward the end surface of the counterpart member. It is in.

  According to a second aspect of the present invention, the annular seal body includes an annular slidable contact surface portion that is in sliding contact with an end surface of the counterpart member and seals between the opposite member, and the annular slidable contact portion is in the axial direction. And an annular concave portion that holds the O-ring in an elastically deformed state between the boss member and the boss member.

  As described above, according to the first aspect of the present invention, since the floating seal composed of the O-ring and the annular seal body is employed as the sealing means of the bearing device, the boss member and the counterpart member are connected via the connecting pin. When relatively rotating, the sliding resistance generated in the sealing means (floating seal) can be kept small, and energy loss can be reduced. In addition, since the annular seal body can seal between the end faces of the mating member and the annular seal body and the boss member can be sealed by the O-ring, foreign matter from entering between the bush and the connecting pin can be prevented. It is possible to prevent the lubricating oil supplied (greased) between the bush and the connecting pin from leaking to the outside, and to increase the lubrication interval of the lubricating oil.

  According to the invention of claim 2, the annular seal body can seal between the opposite member by sliding the annular sliding contact surface portion to the end surface of the opposite member, and the O-ring is formed by the annular concave surface portion. Can be held in an elastically deformed state with the boss member. For this reason, the O-ring in an elastically deformed state can urge the sliding contact surface portion of the annular seal body toward the end surface of the counterpart member, and can stably seal both sliding contact surfaces. Further, for example, an O-ring that is inclined obliquely and is in an elastically deformed state continues to contact between the concave surface portion of the annular seal body and the boss member. Can be sealed.

1 is a front view showing a hydraulic excavator to which a bearing device according to an embodiment of the present invention is applied. It is the expanded sectional view which looked at the bearing apparatus from the arrow II-II direction in FIG. FIG. 3 is an enlarged cross-sectional view showing an O-ring and an annular seal body in FIG. 2 in an exploded state. It is the right view which looked at the annular seal body in FIG. 3 from the right side.

  Hereinafter, a bearing device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4 of the accompanying drawings, taking as an example a case where the bearing device is applied to a pin coupling portion between an arm and an arm cylinder of a hydraulic excavator. In the embodiment, a bracket member provided on an arm will be described as an example as a representative example of a counterpart member that rotatably connects a boss member using a connection pin.

  In the figure, reference numeral 1 denotes a hydraulic excavator as a construction machine, and the hydraulic excavator 1 is composed of a lower traveling body 2 and an upper revolving body 3 that is pivotably mounted on the lower traveling body 2. The upper swing body 3 includes a swing frame 4 on which a cab 5 and a counterweight 6 are provided.

  7 is a work device provided on the front side of the upper swing body 3 so as to be able to be lifted and lowered. The work device 7 includes a boom 8 that is pin-coupled to the front side of the swing frame 4 of the upper swing body 3, and a boom 8. The arm 9 is pin-coupled to the distal end side of the arm 9 and the bucket 10 is a working tool pin-coupled to the distal end side of the arm 9. In the work device 7, the boom 8 is moved up and down by the boom cylinder 11, and the arm 9 is moved up and down with respect to the boom 8 by the arm cylinder 12. The bucket 10 is rotated by the bucket cylinder 13 via the links 14 and 15.

  Here, in the working device 7, between the base end side of the arm 9 and the rod distal end side of the arm cylinder 12, for example, as shown in FIG. Yes. The bearing device 21 includes a boss member 22, a bush 23, bracket members 24 and 25, a connecting pin 26, and a floating seal 31 which will be described later.

  Reference numeral 22 denotes a cylindrical boss member provided on the rod tip side of the arm cylinder 12, and the boss member 22 has a bush fitting hole 22A into which a bush 23 described later is fitted on the inner peripheral side thereof, and the bush. A pair of left and right seal housing grooves 22B, which are notched grooves having an L-shaped cross section and are located on both axial sides of the fitting hole 22, are provided. Each of the seal housing grooves 22B is formed as a diameter-expanded hole portion that opens to both ends in the axial direction of the boss member 22 and has an outer diameter dimension larger than that of the bush fitting hole 22A.

  In addition, a pair of left and right chamfered portions 22 </ b> C are formed on the outer peripheral side of the boss member 22 and are obliquely inclined and located on both sides in the axial direction. In each of the chamfered portions 22C, outer seals 35, 35 are arranged with tightening margins between end surfaces 24B, 25B of bracket members 24, 25 described later.

  Reference numeral 23 denotes a cylindrical bush provided in the bush fitting hole 22A of the boss member 22. The bush 23 is fitted into the bush fitting hole 22A of the boss member 22 by means such as press fitting. Yes. The bush 23 is formed using, for example, a sintered metal material having a large number of pores having a porous structure, and the pores are impregnated with lubricating oil. Further, the inner peripheral side of the bush 23 is a circular pin hole 23A, and a connecting pin 26 described later is slidably inserted into the pin hole 23A.

  Reference numerals 24 and 25 denote left and right bracket members as a pair of counterpart members arranged with the boss member 22 sandwiched from both the left and right sides. In the present embodiment, bracket members 24 and 25 provided on the proximal end side of the arm 9 are illustrated as representative examples of the counterpart member with respect to the boss member 22. Here, as shown in FIG. 2, the bracket members 24 and 25 are disposed so as to sandwich the boss member 22 from the left and right sides, and are rotated relative to the boss member 22 by a connecting pin 26 described later. Connected as possible. The bracket members 24 and 25 are provided with circular pin holes 24A and 25A at positions corresponding to the pin holes 23A of the bush 23.

  The inner surfaces of the bracket members 24 and 25 are end surfaces 24B and 25B that face the boss member 22 in the axial direction, and a portion of the end surfaces 24B and 25B where an annular seal body 32 described later is slidably contacted is smooth. It is formed as a surface. Further, the other side bracket member 25 located on the right side in FIG. 2 is provided with a stepped convex portion 25C protruding outward in the axial direction, and the pin hole 25A extends in the axial direction in the stepped convex portion 25C. It is formed to penetrate through. Further, an insertion hole 25D through which a fixing bolt 27 described later is inserted is formed in the stepped convex portion 25C of the bracket member 25 in the radial direction.

  A connecting pin 26 connects the boss member 22 between the bracket members 24, 25. The connecting pin 26 is slidably inserted into the pin hole 23 A of the bush 23 in the lengthwise intermediate portion, and the connecting pin 26. Both end sides of the bracket members 24 and 25 are inserted into pin holes 24A and 25A. A circular recess 26A is formed on the end surface of the connecting pin 26 on one side in the axial direction (left side in FIG. 2), and a greasing nipple 29 described later is attached to and detached from the bottom located on the back side of the recess 26A. It is screwed on as possible.

  Further, the connecting pin 26 is formed with a greasing passage 26B for supplying lubricating oil between the pin hole 23A of the bush 23 and the outer peripheral surface of the connecting pin 26, and the greasing passage 26B is formed in the recess 26A. The bottom side is closed by a greasing nipple 29 described later. On the other hand, on the other axial side of the connecting pin 26 (right side in FIG. 2), an insertion hole 26C through which a fixing bolt 27 described later is inserted is formed in the radial direction. The insertion hole 26 </ b> C is coaxially aligned in the circumferential direction of the insertion hole 25 </ b> D of the bracket member 25 and the connecting pin 26.

  Reference numeral 27 denotes a fixing bolt as a fixing member for preventing the connection pin 26 from being removed. The fixing bolt 27 is inserted into the insertion hole 25D of the bracket member 25 and the insertion hole 26C of the connection pin 26 as shown in FIG. In this state, a nut 28 is screwed onto the distal end side of the fixing bolt 27. As a result, the fixing bolt 27 holds the connecting pin 26 in a state where it is prevented from being pulled out with respect to the bracket members 24, 25, and restricts the connecting pin 26 from rotating relative to the bracket members 24, 25. It is also something that holds.

  Reference numeral 29 denotes a greasing nipple provided in the recess 26A of the connecting pin 26. The greasing nipple 29 is detachably screwed to the back (bottom) side of the recess 26A. For example, when lubricating oil such as grease is supplied using a greasing tool (not shown) such as a grease gun, the greasing tool is set at the position of the greasing nipple 29, and in this state, the connecting pin 26 Lubricating oil such as grease is supplied into the oil supply passage 26B. At this time, the oil supply oil is pushed out into the oil supply passage 26B in a pressurized state and supplied to the sliding surface between the pin hole 23A of the bush 23 and the outer peripheral surface of the connecting pin 26.

  30 and 30 are a pair of left and right seal members that seal between the bracket members 24 and 25 and the connecting pin 26, and one of the seal members 30 is connected to the pin hole 24A of the bracket member 24. It is arranged between the outer peripheral surface of the connecting pin 26 and prevents foreign matter from entering between them, and the lubricating oil (grease oil) leaks out between the two in the axial direction. prevent. The other seal member 30 is disposed between the pin hole 25A of the bracket member 25 and the outer peripheral surface of the connecting pin 26, and prevents foreign matter from entering between the two, and the lubricating oil ( (Grease oil) is prevented from leaking out between the two in the axial direction.

  Reference numerals 31 and 31 denote floating seals that are located on both axial ends of the bush 23 and constitute a pair of left and right sealing means provided between the boss member 22 and the connecting pin 26. These floating seals 31 seal the space between the end surface sides (seal housing grooves 22B) of the boss members 22 facing each other in the axial direction and the end surfaces 24B, 25B of the bracket members 24, 25 in a floating state. That is, each floating seal 31 is arranged in an elastically deformed state between an annular seal body 32 inserted through the outer peripheral side of the connecting pin 26 with a gap and the annular seal body 32 and the seal housing groove 22B of the boss member 22. And an O-ring 33.

  When the boss member 22 rotates around the connecting pin 26 between the left and right bracket members 24, 25, the annular seal body 32 of the floating 31 is tightened by the O-ring 33, and therefore, together with the boss member 22. The sliding contact surface portion 32D described later is in sliding contact with the end surfaces 24B and 25B of the bracket members 24 and 25 so as to rotate relative to each other. That is, the floating seal 31 holds the annular seal body 32 in a floating state (floating state) by the O-ring 33 between the seal receiving groove 22B of the boss member 22 and the outer peripheral surface of the connecting pin 26, as described later. It exhibits a sealing function.

  Here, the annular sealing body 32 is made of, for example, a metal material such as cast iron or steel, or a rigid material such as ceramics or hard resin, and the cross-sectional shape is substantially J-shaped or substantially L-shaped as shown in FIGS. It is formed as a ring having a shape, and an inner peripheral side thereof is a pin insertion hole 32 </ b> A formed to have a larger diameter than the outer diameter of the connecting pin 26. The annular seal body 32 has a facing surface portion 32B and a tapered surface portion 32C on both sides in the axial direction of the pin insertion hole 32A, and the facing surface portion 32B is disposed to face the axial end surface of the bush 23 via a gap. The tapered surface portion 32C is formed to be inclined obliquely between a sliding contact surface portion 32D described later and the pin insertion hole 32A, and an oil reservoir 34 described later is defined inside the tapered surface portion 32C.

  The annular seal body 32 includes an annular sliding contact surface portion 32D positioned on the radially outer side of the tapered surface portion 32C, and a radially outer portion of the opposing surface portion 32B on the opposite side of the annular sliding contact surface portion 32D in the axial direction. And an annular concave surface portion 32E formed so as to be cut out in an arc shape. The annular slidable contact surface portion 32D is urged against the end surfaces 24B and 25B of the bracket members 24 and 25 by the elastically deformed O-ring 33 to slidably contact the end surfaces 24B and 25B and seal between the bracket members 24 and 25. Make up surface.

  As shown in FIG. 3, the concave surface portion 32 </ b> E of the annular seal body 32 is formed as an arcuate concave curved surface inclined obliquely, and sandwiches the O-ring 33 between the boss member 22 and the seal housing groove 22 </ b> B from an oblique direction. The structure is held in an elastically deformed state. At this time, the elastically deformed O-ring 33 is in a state of being inclined obliquely by making wide surface contact with the concave surface portion 32E of the annular seal body 32, and is also in contact with the seal housing groove 22B of the boss member 22 with tightening allowance. Kept in a state.

  Thus, a stable seal state is maintained between the seal housing groove 22B of the boss member 22 and the annular seal body 32 by the O-ring 33 having a tightening allowance. Further, between the end surfaces 24B and 25B of the bracket members 24 and 25 and the annular seal body 32, the annular sliding contact surface portion 32D is in sliding contact with the end surfaces 24B and 25B, thereby maintaining a sealed state therebetween. As a result, the axially opposite sides of the boss member 22 and the end surfaces 24B and 25B of the bracket members 24 and 25 are sealed in a floating state by the floating seal 31 including the annular seal body 32 and the O-ring 33, and the internal lubricating oil Is prevented from leaking to the outside, and a sealing function is exerted together with an outer seal 35 described later against entry of foreign matter.

  34 and 34 are oil reservoirs that are located on the outer peripheral side of the connecting pin 26 and defined between the end surfaces 24B and 25B of the bracket members 24 and 25 and the respective annular seal bodies 32. The oil reservoir 34 is formed as a substantially triangular gap between the end surfaces 24B, 25B of the bracket members 24, 25 and the connecting pin 26 by the tapered surface portion 32C of the annular seal body 32, and the oil supply oil is contained therein. A part of this is stored.

  Reference numerals 35 and 35 denote outer seals mounted from the outside between the chamfered portions 22C of the boss member 22 and the end surfaces 24B and 25B of the bracket members 24 and 25, respectively. These outer seals 35 are formed by using, for example, O-rings, and are located outside in the radial direction of the floating seal 31 so that external dust or the like enters the gap between the boss member 22 and the bracket members 24 and 25. Is to prevent

  The bearing device 21 applied to the hydraulic excavator 1 according to the present embodiment has the above-described configuration. When excavation work such as earth and sand is performed by the working device 7 of the hydraulic excavator 1, the rod tip side of the arm cylinder 12 is used. The base end side of the arm 9 that is pin-coupled via the bearing device 21 rotates around the connecting pin 26 according to the expansion / contraction operation of the arm cylinder 12. That is, the boss member 22 is relatively displaced between the left and right bracket members 24 and 25 so as to rotate around the connecting pin 26 together with the bush 23.

  When the arm 9 rotates, the viscosity of the lubricating oil impregnated in the bush 23 decreases due to frictional heat between the bush 23 and the connecting pin 26, and therefore the sliding between the bush 23 and the connecting pin 26 from the inside of the bush 23 occurs. The oil oozes out to the moving surface, and an oil film can be formed on the sliding surface between the bush 23 and the connecting pin 26 by this lubricating oil. Further, during maintenance of the hydraulic excavator 1, for example, a lubricating oil such as a grease gun can be used to supply lubricating oil into the greasing passage 26B of the connecting pin 26, and this also causes the sliding surface between the bush 23 and the connecting pin 26 to be supplied. Can be kept in a lubricated state.

  Here, in the present embodiment, an annular seal body 32 and an O-ring 33 are provided between the seal housing grooves 22B of the boss member 22 and the end faces 24B, 25B of the bracket members 24, 25 on the outer peripheral side of the connecting pin 26. It is set as the structure which provides the floating seal 31 which consists of these. The annular seal body 32 includes an annular slidable contact surface portion 32D that is in sliding contact with the end surfaces 24B and 25B of the bracket members 24 and 25 and seals between the bracket members 24 and 25, and the annular slidable contact surface portion 32 is in the axial direction. And an annular concave portion 32E that holds the O-ring 33 in an elastically deformed state between the boss member 22 and the seal housing groove 22B.

  Accordingly, the floating seal 31 is elastically deformed while the annular seal body 32 is held in a floating state (floating state) by the O-ring 33 between the seal housing groove 22B of the boss member 22 and the outer peripheral surface of the connecting pin 26. The annular sliding contact surface portion 32D can be brought into sliding contact with the end surface 24B (25B) of the bracket member 24 (25) by the biasing force of the O-ring 33, and the sliding contact surface can be kept in a sealed state.

  For this reason, when the boss member 22 and the bracket members 24 and 25 are rotated relative to each other via the connecting pin 26, the sliding resistance acting on the annular seal body 32 of the floating seal 31 is suppressed to reduce energy loss. can do. In addition, the space between the end surface 24B (25B) of the bracket member 24 (25) can be sealed by the sliding contact surface portion 32D of the annular seal body 32, and the space between the seal housing groove 22B of the boss member 22 can be sealed by the O-ring 33. Can do.

  Therefore, according to the present embodiment, by adopting the floating seal 31, it is possible to prevent foreign matters from entering between the bush 23 and the connecting pin 26, and between the bush 23 and the connecting pin 26. It is possible to prevent the lubricating oil supplied (greased) in the meantime from leaking to the outside, and to increase the lubrication interval of the lubricating oil.

  Further, according to the present embodiment, the pair of seal housing grooves 22B are provided on the inner peripheral side of the boss member 22 located on both ends in the axial direction of the bush 23, and the concave surface portion 32E of the annular seal body 32 is shown in FIG. As shown in FIG. 3, the O-ring 33 is sandwiched from the oblique direction between the boss member 22 and the seal housing groove 22B and held in an elastically deformed state.

  As a result, the O-ring 33 that is elastically bent and deformed is in a state of being inclined obliquely by making wide surface contact with the concave surface portion 32E of the annular seal body 32, and is also tightened with respect to the seal housing groove 22B of the boss member 22. Is held in contact. As a result, a stable sealing state can be maintained between the seal housing groove 22B of the boss member 22 and the annular seal body 32 by the O-ring 33 having a tightening allowance, and the end surfaces 24B, 25B of the bracket members 24, 25 are secured. The annular slidable contact surface portion 32D is in slidable contact with the end surfaces 24B and 25B so that the sealed state between the two can be maintained.

  For this reason, between the axial direction both side end surfaces of the boss member 22 and the end surfaces 24B, 25B of the bracket members 24, 25 can be stably sealed by the floating seal 31 including the annular seal body 32 and the O-ring 33, The internal lubricating oil can be prevented from leaking to the outside. Further, with respect to the entry of foreign matter from the outside, the double seal function can be exhibited by the outer seal 35 and the floating seal 31.

  Further, between the pin holes 24A, 25A of the bracket members 24, 25 and the connecting pin 26, left and right seal members 30 constituted by, for example, O-rings are provided. It is possible to prevent foreign matters from entering between the two, and for example, it is possible to prevent the lubricating oil (greased oil) in the oil reservoir 34 from leaking out between the two in the axial direction. .

  In the embodiment, the bearing device 21 provided between the base end side of the arm 9 and the rod tip end side of the arm cylinder 12 among the plurality of bearing devices used in the working device 7 has been described as an example. However, the present invention is not limited to this, and may be applied to a bearing device used between the bottom side of the arm cylinder 12 and the boom 8 side, a bearing device used for the boom cylinder 11 or the bucket cylinder 13, for example. Further, a bearing device used between the arm 9 and the bucket 10 of the working device 7, a bearing device used between the tip of the boom 8 and the arm 9, and a bearing device used between the foot portion of the boom 8 and the swing frame 4. You may apply to.

  In this case, the counterpart member connected to the boss member using the connecting pin is not limited to the left and right bracket members 24 and 25 as described in the above embodiment, and for example, the arm cylinder 12 shown in FIG. The counterpart member for the bottom mounting eye (boss member) is a pair of left and right brackets provided on the boom 8. 1 is a pair of left and right brackets provided on the arm 9 with respect to the mounting eye (boss member) on the bottom side of the bucket cylinder 13 shown in FIG. Furthermore, for example, end portions (end portions to which the connecting pins are attached) of the links 14 and 15 shown in FIG. 14 also serve as counterpart members.

  Further, in the above embodiment, the case where the bearing device is applied to a hydraulic excavator has been described as an example. However, the present invention is not limited to this, and can be widely applied to bearing devices used in other construction machines such as a hydraulic crane, a wheel loader, and a bulldozer.

1 Hydraulic Excavator 7 Working Device 8 Boom 9 Arm 10 Bucket (Working Tool)
11 Boom cylinder 12 Arm cylinder 13 Bucket cylinder (work implement cylinder)
21 Bearing device 22 Boss member 22A Bushing fitting hole 22B Seal receiving groove 23 Bushing 23A, 24A, 25A Pin hole 24, 25 Bracket member (counter member)
24B, 25B End face 26 Connecting pin 31 Floating seal (sealing means)
32 annular seal body 32A pin insertion hole 32B opposing surface portion 32C taper surface portion 32D sliding contact surface portion 32E concave surface portion 33 O-ring 34 oil reservoir 35 outer seal

Claims (2)

A boss member fitted with a bush on the inner peripheral side, a connecting pin that is inserted into the inner peripheral side of the bush and pivotally connects the boss member to a counterpart member, and both axial ends of the bush In a bearing device comprising a sealing means located between the boss member and the connecting pin,
The sealing means is constituted by a floating seal that seals in a floating state between an end surface of the boss member and an end surface of the counterpart member facing each other in the axial direction,
The floating seal is inserted into the outer peripheral side of the connecting pin, and an annular seal body that is in sliding contact with the end surface of the counterpart member and seals between the counterpart member, and a seal between the annular seal body and the boss member Therefore, an O-ring that is arranged in an elastically deformed state between the annular seal body and the boss member and elastically biases the annular seal body toward the end surface of the counterpart member is provided. Bearing device.   The annular seal body includes an annular slide contact surface portion that is in sliding contact with an end surface of the counterpart member and seals between the counterpart member, and the annular slide contact surface portion is formed on the opposite side in the axial direction from the boss member. The bearing device according to claim 1, further comprising an annular concave surface portion that holds the O-ring in an elastically deformed state.

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