JPH0442572Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a sealing device for a rolling bearing.
In particular, the sealing performance of a contact type sealing device having a ventilation groove communicating with the outside of the bearing is improved.

[Conventional technology]

Conventionally, in rolling bearings sealed with contact-type seal bodies, the pressure inside the bearing may drop and become negative pressure due to temperature changes or other usage conditions, or conversely, the internal pressure may rise. The pressure may be higher than that outside the bearing.

When the internal pressure of the bearing becomes negative, the lip of the seal body is attracted to the seal groove, increasing the torque of the bearing and impeding rotational performance.On the other hand, when the internal pressure of the bearing increases, the lip of the seal body is attracted to the seal groove. This may cause the problem that it may come off and impair sealing performance.

Therefore, as a means to eliminate such problems, a sealing device with an internal pressure adjustment mechanism is provided in which a ventilation groove is provided in the fixed part of the seal body and/or the lip to communicate between the inside and outside of the bearing. is known, in which air flows into the bearing through ventilation grooves and air is discharged to the outside of the bearing when the internal pressure of the bearing fluctuates.

[Problem that the invention attempts to solve]

In the above-mentioned sealing device with an internal pressure adjustment mechanism, the inside and outside of the bearing are always in communication through the ventilation groove of the seal body. However, even if the ventilation grooves are made small, sufficient sealing performance cannot be obtained when the bearing is used in locations where it may be exposed to water or when the bearing is used underwater. In addition, there is a problem in that the ventilation grooves are closed by grease scattered inside the bearing, preventing smooth air flow.

This invention solves the above problems and prevents foreign matter from outside the bearing without impairing the bearing's internal pressure adjustment function.
In particular, it is an object of the present invention to provide a sealing device having a function of preventing water from entering.

[Means for solving the problem] The sealing device of this invention has a bearing on at least one of the fixing surface of the fixing part of the seal body with the seal fixing groove and the contact surface of the lip part with the seal sliding groove. A ventilation groove is provided to communicate the inside and outside.

The ventilation groove provided in at least one of the fixing portion and the lip portion of the seal body is provided with a thin portion at the open end facing the outside of the bearing to close the ventilation groove.

The thin wall portion that closes the ventilation groove has a wall thickness that allows it to be elastically deformed in accordance with fluctuations in the internal pressure of the bearing.

[Effect]

In the sealing device of this invention, when the internal pressure of the bearing fluctuates, the thin part that closes the ventilation groove provided in at least one of the fixed part and the lip of the seal body elastically deforms in accordance with the internal pressure, thereby fixing the seal body. On the lip side of the seal body, there is a gap between the seal fixing groove of the bearing fixed ring and the outer circumferential edge of the fixed part of the seal body that is in close contact with this groove, and on the lip side of the seal body, there is a gap between the seal sliding groove of the bearing rotating ring and this gap. A gap is created between the lip of the seal and the inner circumferential edge of the seal body that is in contact with the seal body, and air flows into the bearing interior and air is discharged to the outside of the bearing through a ventilation path opened through these gaps.

In addition, under operating conditions with little variation in the internal pressure of the bearing or when the bearing is not rotating, the open end of the ventilation groove provided on at least one of the fixed side and the lip side of the seal body is blocked by the thin wall part. This prevents foreign matter or water from entering from outside the bearing.

〔Example〕

Examples of this invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional side view of the upper half of an embodiment of this invention, and FIG. 2 is a rear view showing the main parts of the seal body.

In FIG. 1, balls 15 are rotatably interposed between an outer ring (fixed ring) 10 and an inner ring (rotating ring) 20.
Both ends of the outer ring 10 and the inner ring 20 are provided with seal bodies 3.
2 is an example of a ball bearing sealed by 0 (only one end face side is shown).

The outer ring 10 has a seal fixing groove 11 formed in the circumferential direction on the inner circumferential surface on the end face side, and the inner ring 20 has a seal sliding groove 21 formed in the circumferential direction on the outer circumferential face on the end face side.

The seal body 30 is an annular plate made of an elastic body such as rubber and reinforced by a core metal 31, and has a fixing part 32 formed on its outer circumferential side and a lip part 36 formed on its inner circumferential side. There is. This lip portion 36 has
Main lip 37 tilting axially inward
A first auxiliary lip 38a branches from the base side of the main lip 37 and extends axially inward, and a second auxiliary lip 38b extends radially inward from the axial outside of the main lip 37. It is being

This seal body 30 connects the inner and outer surfaces of the fixing portion 32 to the seal fixing groove 11 of the outer ring 10, respectively.
The main lip 37 of the lip portion 36 is fixed in close contact with the inner step surface and the outer slope of the inner ring 20.
The bearing is sealed by contacting the inner slope of the seal sliding groove 21. The first auxiliary lip 38a protrudes inward of the bearing and has the function of guiding the flow of grease sealed inside the bearing toward the inside of the bearing, and the second auxiliary lip 38b
is opposed to the outer circumferential surface of the end portion of the inner ring 20 with an appropriate gap therebetween, and functions to prevent foreign matter from entering from outside the bearing.

The fixing portion 32 of the seal body 30 has one or more ventilation grooves 33 provided in the radial direction on the inner surface thereof, which communicate with the inside of the bearing, and one or more ventilation grooves 33 on the outer diameter surface thereof. A ventilation groove 34 is provided in the axial direction. The radial ventilation groove 33 and the axial ventilation groove 34 are provided at different positions in the circumferential direction; They communicate with each other via a space 13 formed between them. Fixed part 3
A fixing portion 32 is provided at the open end of the ventilation groove 34 on the outer diameter surface of No. 2 facing the outside of the bearing at the axially outer edge.
Thin wall portion 35 having the same surface as the outer surface and outer diameter surface of
is provided, and the ventilation groove 34 is formed by this thin wall portion 35.
is blocked.

The main lip 37 of the lip portion 36 of the seal body 30 is also provided with one or more ventilation grooves 39 on its tip surface from the inner circumferential edge to the outer circumferential edge, and the open end on the outer circumferential side faces the inside of the bearing. The opening end on the side facing the outside of the bearing on the inner circumferential edge side is closed by a thin wall portion 40 provided on the same surface as the distal end surface of the main lip portion 37.

The wall thicknesses of the fixed-side thin-walled portion 35 and the lip-side thin-walled portion 40 of the seal body 30 swell when the internal pressure fluctuates up and down to a predetermined value while the bearing is in use, following the fluctuations. The thickness is selected so that it can be elastically deformed to a certain degree.

The ball bearing in which the seal body 30 having the above configuration is assembled has the axial ventilation groove 34 provided in the fixed portion 32 of the seal body 30 and the ventilation groove 39 provided in the main lip 37 on the side facing the outside of the bearing. Since the opening ends of the openings are respectively closed by the thin wall portions 35 and 40, the seal body 30 completely seals the opening ends.

Therefore, the pressure inside the bearing fluctuates due to temperature changes and other usage conditions during use of the bearing, but The thickness is such that it elastically deforms following fluctuations in bearing internal pressure, so when the bearing internal pressure drops below a predetermined value, it bulges inside the bearing, and conversely, when the bearing internal pressure exceeds a predetermined value, When it rises, it bulges to the outside of the bearing, and between the outer peripheral edge of the fixing part 32 of the seal body 30 and the seal fixing groove 11 of the outer ring 10, there is a surface where the thin part 35 is in contact with the seal fixing groove 11. A gap is generated between the inner peripheral edge of the main lip 37 of the seal body 30 and the seal sliding groove 21 of the inner ring 20 on the surface where the thin wall portion 40 is in contact with the seal sliding groove 21.
FIG. 1 shows a state in which the thin-walled portions 35 and 40 bulge outward from the bearing. Therefore, between the outer ring 10 and the seal body 30, the fixed portion 3 of the seal body 30
2 and the seal fixing groove 11 of the outer ring 10, the ventilation grooves 33 and 34 communicate with the outside of the bearing through the gap created in the thin wall part 35, and the airflow grooves 33 and 34 communicate with the outside of the bearing through the gap created in the thin wall part 35. An open ventilation path is formed, and between the inner ring 20 and the seal body 30, the ventilation groove 39 of the main lip 37 of the seal body 30 is connected to the thin wall portion 40.
A ventilation path is formed that communicates with the outside of the bearing through the gap created between the two, and is open to the inside and outside of the bearing.

In this way, when the internal pressure of the bearing fluctuates below or above a predetermined value, air flows into the inside of the bearing and out of the bearing through the ventilation path opened between the outer ring 10, the inner ring 20, and the seal body 30. Since the air is discharged and the bearing internal pressure can be adjusted, the main lip 37 of the seal body 30 always contacts the seal sliding groove 21 with a constant contact pressure, increasing the torque and reducing the rotational performance. This will not occur, and the problem of the main lip 37 coming off the seal sliding groove 21 and impairing the sealing performance will not occur.

Furthermore, when the bearing is used under normal conditions with little variation in internal pressure, or when the bearing is not rotating, both the ventilation groove 34 of the fixed part 32 of the seal body 30 and the ventilation groove 39 of the main lip 37 are Since the open ends are closed by the thin walled portions 35 and 40, foreign matter will not enter from outside the bearing, and water will be prevented from entering even when the bearing is used in a place where it gets wet or underwater. In addition to being highly waterproof, it also prevents grease from leaking to the outside of the bearing.

In the above embodiment, a bearing was described in which a ventilation groove was provided on both the fixed side and the lip side of the seal body, and the open end of the ventilation groove was closed with a thin part. This invention can be applied to bearings provided on either side in the same manner as described above.

In addition, the seal body of the above embodiment is of a type that is fixed to the outer ring of the bearing, but a fixing part is formed on the inner circumference side of the seal body and a lip part is formed on the outer circumference side, so that the seal body is tightly fixed to the inner ring of the bearing. The same configuration as described above can also be used for the other types.

The details of the structure of the seal body itself, such as its shape, number of lips, shape and size of ventilation grooves, are not limited to those of the above embodiments, but also for contact type seal bodies of other structures. This idea can be applied.

[Effect of idea]

As explained above, the sealing device of this invention has a ventilation groove communicating between the inside and outside of the bearing on at least one of the fixed side and the lip side of the contact type seal body assembled on the end face side of the rolling bearing. The opening end of the ventilation groove is closed by a thin portion that elastically deforms in accordance with fluctuations in the internal pressure of the bearing. Therefore, according to this invention, when the internal pressure of the bearing fluctuates, the thin wall portion swells and acts as a valve body that communicates between the inside and outside of the bearing, allowing air to flow in and out. Therefore, it not only becomes a sealing device with an internal pressure adjustment mechanism, but also has excellent sealing performance because, under normal usage conditions, foreign matter and water from outside the bearing are blocked by the thin wall and do not enter the inside of the bearing. Can be used as a rolling bearing.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional side view of the upper half of an embodiment of this invention, and FIG. 2 is a rear view showing the main parts of the seal body. In the figure, 10 is an outer ring, 11 is a seal fixing groove, and 20
is the inner ring, 21 is the seal sliding groove, 30 is the seal body,
32 is a fixed part, 33 and 34 are ventilation grooves of the fixed part, 3
5 is a thin wall portion, 37 is a main lip, 39 is a ventilation groove of the main lip, and 40 is a thin wall portion.

Claims (1)

[Scope of utility model registration request] The fixed part of the seal body made of an elastic material such as rubber is fixed in close contact with the seal fixing groove of the fixed ring of the rolling bearing, and the lip part is assembled with the seal sliding contact groove of the rotating ring. In a sealing device in which a ventilation groove communicating with the inside and outside of the bearing is provided on at least one of the fixing surface of the fixing part with the seal fixing groove and the contact surface of the lip part with the seal sliding groove, the fixing part of the seal body and the contact surface with the seal sliding groove of the lip part are provided. The ventilation groove provided on at least one side of the lip portion is provided with a thin wall portion that closes the open end on the side facing the outside of the bearing, and the thickness of the thin wall portion can be elastically deformed to follow fluctuations in the internal pressure of the bearing. A sealing device for a rolling bearing characterized by its thickness.