WO2015072471A1

WO2015072471A1 - Bearing unit

Info

Publication number: WO2015072471A1
Application number: PCT/JP2014/079918
Authority: WO
Inventors: 恵一興梠; 祥子諏訪園
Original assignee: 株式会社明電舎
Priority date: 2013-11-15
Filing date: 2014-11-12
Publication date: 2015-05-21
Also published as: JP2015096737A

Abstract

The present invention prevents the leakage of grease associated with breathing. A bearing unit (1) is configured by installing a sealed bearing (20) on a bearing box (10). A ventilation groove (31) which makes a circuit in the circumferential direction is formed on the outer circumferential surface of an outer wheel (21), and multiple outer wheel ventilation holes (32) which bring an inner space and the ventilation groove (31) in communication with one another is formed on the outer wheel (21). Moreover, a bearing box ventilation hole (33) which brings an outer space and the ventilation grove (31) in communication with one another is formed on the bearing box (10). A ventilation structure (30) is configured by means of the aforementioned ventilation groove (31), outer wheel ventilation holes (32), and bearing box ventilation hole (33). It is possible to prevent grease from leaking from the lip part and such of an oil seal (24) because the airflow from breathing is produced via the ventilation structure (30).

Description

Bearing unit

The present invention relates to a bearing unit using a sealed bearing, which is devised to prevent the leakage of lubricating oil due to a breathing action and to allow the lubricating oil to be replenished to the sealed bearing, thereby extending the life. is there.

A rotating shaft of a rotating device such as an electric motor is rotatably supported by a bearing unit. The bearing unit is configured by incorporating a bearing into a bearing box.
When the bearing unit is classified as a classification standard of a bearing or a bearing housing, it is classified into a sealed bearing unit and an open bearing unit.

The sealed bearing unit uses a sealed bearing as a bearing. In a sealed bearing, lubricating oil (grease or the like) is sealed in the internal space of the bearing, and sealing members (oil seals or the like) are disposed at both ends in the axial direction of the bearing to perform sealing. In this way, the lubricating oil sealed in the inner space of the bearing is prevented from leaking outside.

On the other hand, the open bearing unit uses an open bearing that does not have a sealing function. In this open bearing unit, a seal material for preventing the lubricating oil (grease, etc.) supplied to the bearing from leaking outside is disposed in the bearing housing. Further, the bearing box is provided with an oil supply / discharge oil structure including an oil supply hole and an oil discharge hole. Through this supply / discharge oil structure, lubricating oil can be supplied / discharged to / from the bearing.

JP 2001-59524 A JP 2013-50193 A

The sealed bearing unit has the advantages of small size, light weight and low cost. On the other hand, there is a problem that the bearing life is limited and shortened by the life of the enclosed lubricating oil.

Further, in the sealed bearing unit, there is a breathing action accompanying the temperature change. The breathing action means that when the temperature of the sealed bearing changes from low temperature to high temperature, the air present in the internal space of the sealed bearing thermally expands, and a part of the air is a minute gap in the sealed bearing or an oil seal that is a sealing member. When the temperature of the sealed bearing changes from high temperature to low temperature, the air existing in the inner space of the sealed bearing is thermally contracted, and the outside air is very small in the sealed bearing. It refers to a phenomenon of entering the internal space of the sealed bearing through a gap or a lip portion of an oil seal that is a sealing member.
With such a breathing action, especially when air leaks from the inside of the sealed bearing to the outside, the lubricating oil (grease, etc.) enclosed in the sealed bearing may gradually leak out to the outside, albeit minutely. is there.

In general, an electric motor incorporated in an elevator hoist has a high frequency of operation / stop, a high frequency of operation / stop in the daytime, and a low frequency of operation / stop in the nighttime. For this reason, when a sealed bearing unit is used as a bearing unit for such an electric motor for an elevator, the temperature rise due to heat generation during operation and the temperature decrease due to stop are frequently repeated, resulting in a lubricating oil accompanying breathing action. The amount of leakage (grease, etc.) tends to increase.
Note that breathing may occur due to fluctuations in the outside air temperature.

On the other hand, the open bearing unit has an advantage that the bearing life can be greatly prolonged by periodically replenishing the lubricating oil. On the other hand, since it is necessary to provide the bearing housing with a seal for preventing leakage of lubricating oil and a supply / discharge oil structure, there is a disadvantage that the dimensions are large and heavy and the manufacturing cost is high.

At present, there are only two bearing units, the sealed bearing unit and the open bearing unit. For this reason, when a sealed bearing unit is to be adopted as a bearing unit for a product (for example, an electric motor), an open bearing unit must be selected if it is expected that the service life will be insufficient. become.
When such a selection is made, there is a problem that the size, weight, and cost are significantly increased. In addition, since the size and weight of the open bearing unit are large, there may be a problem that the product cannot be realized as a product.

Therefore, the appearance of a longer-life bearing unit based on a sealed bearing unit is eagerly desired, but this life is limited by the life of the lubricating oil enclosed in the sealed bearing and affects the life of the lubricating oil. There are the following two.
・ Lubrication performance deterioration due to aging deterioration of lubricant ・ Lubrication oil decrease due to leakage caused by use (insufficiency)

Among these, the technology for extending the life due to aging of lubricating oil has been established by considering the selection of high-performance grease and the use conditions.
On the other hand, with regard to the decrease (insufficiency) of the lubricating oil, it is impossible to avoid the problem that the lubricating oil decreases and the service life is shortened when it is used for a long period of time. The reason is that the amount of grease enclosed in the sealed bearing is limited to about 30% of the internal capacity of the bearing, and a small amount of leakage from the seal portion that occurs continuously during use (according to the respiratory action) This is because it is impossible to eliminate any leakage.

The present invention has been made in view of the above prior art, and an object of the present invention is to provide a bearing unit using a sealed bearing which can prevent leakage of lubricating oil accompanying respiration and can be replenished with lubricating oil.

The configuration of the present invention for solving the above problems is as follows.
In the bearing unit assembled with the sealed bearing inserted in the bearing insertion space formed in the bearing housing,
A ventilation groove, which is a groove that makes a round along the circumferential direction, on a surface that contacts the bearing housing of the outer peripheral surface of the outer ring of the sealed bearing or a bearing mounting surface that contacts the outer peripheral surface of the outer ring of the bearing housing. Formed,
The outer ring is formed with an outer ring ventilation hole that communicates the inner groove side space and the ventilation groove with respect to the outer ring at a plurality of locations in the circumferential direction.
The bearing box is formed with a bearing box ventilation hole that communicates the outer space outside the bearing box with the ventilation groove.

The configuration of the present invention is as follows.
The bearing box vent has an inner vent opening to the vent groove and an outer vent opening to the outer space, and the inner vent has a round in the circumferential direction. The outer vent is arranged at a position above the inner vent, and the outer vent is arranged at any position on the upper half circumference.

The configuration of the present invention is as follows.
The bearing box is formed with a bearing box oil supply hole that communicates the outer space outside the bearing box with the ventilation groove, and the bearing hole oil supply hole is disposed at a position lower than the bearing box ventilation hole. It is characterized by.

According to the present invention, since the ventilation structure constituted by the ventilation groove, the outer ring ventilation hole, and the bearing box ventilation hole is provided, the flow of air by breathing action is performed through the ventilation structure. It is possible to prevent leakage from the gap or the tip of the sealing member. Thereby, the lifetime of a bearing unit can be extended.

Also, by further forming a bearing box oil supply hole that communicates the external space with the ventilation groove, lubricating oil can be supplied through the bearing box oil supply hole, the ventilation groove, and the outer ring ventilation hole. Thereby, the lifetime of a bearing unit can be extended.

1 shows a bearing unit according to Embodiment 1 of the present invention, and is a cross-sectional view taken along a broken line indicated by an alternate long and short dash line passing through points A, O, and B in FIG. 1B. It is an end elevation which shows the bearing unit which concerns on Example 1 of this invention. It is sectional drawing which shows the bearing unit which concerns on the 1st modification of Example 1 of this invention, and follows the broken line shown by the dashed-dotted line which passes along the point A, O, B in FIG. 2B. It is an end elevation which shows the bearing unit which concerns on the 1st modification of Example 1 of this invention. The bearing unit which concerns on the 2nd modification of Example 1 of this invention is shown, and it is sectional drawing in alignment with the broken line shown by the dashed-dotted line which passes along point A, O, B in FIG. 3B. It is an end elevation which shows the bearing unit which concerns on the 2nd modification of Example 1 of this invention. FIG. 5 shows a bearing unit according to Embodiment 2 of the present invention, and is a cross-sectional view taken along a broken line indicated by an alternate long and short dash line passing through points A, O, and B in FIG. 4B. It is an end elevation which shows the bearing unit which concerns on Example 2 of this invention.

Hereinafter, the bearing unit according to the present invention will be described in detail based on examples.

[Example 1]
1A and 1B show a bearing unit 1 according to Embodiment 1 of the present invention. FIG. 1A is a cross-sectional view taken along a broken line indicated by a dashed line passing through points A, O, and B in FIG. 1B, and FIG. It is.
The bearing unit 1 rotatably supports a rotating shaft S of an electric motor, and is configured with a bearing box 10, a sealed bearing 20, and a ventilation structure 30 as main members.
The bearing box 10 and the sealed bearing 20 have the same configuration as a conventional sealed bearing unit. In this embodiment, the bearing box 10 and the sealed bearing 20 are newly provided with a ventilation structure 30.

A cylindrical bearing insertion space 11 is formed in the bearing box 10. The sealed bearing 20 is assembled to the bearing housing 10 in a state of being inserted into the bearing insertion space 11. The sealed bearing 20 is assembled to the bearing housing 10 with the outer peripheral surface of the outer ring 21 of the sealed bearing 20 in contact with the cylindrical bearing mounting surface 12 that forms the bearing insertion space 11 in the bearing housing 10. .

The sealed bearing 20 includes an outer ring 21 fixed to the bearing mounting surface 12 of the bearing housing 10, an inner ring 22 fixed to the outer peripheral surface of the rotary shaft S, a rolling element (roller) 23, and shafts of the outer ring 21 and the inner ring 22. It is comprised by the oil seals 24 and 24 which are the sealing members arrange | positioned at the both ends of a direction. The oil seals 24, 24 are fixed to the outer ring 21, and the lip portions (tip portions) of the oil seals 24, 24 are in sliding contact with the outer peripheral surface of the inner ring 22 for sealing.

Grease that is lubricating oil is sealed in the internal space of the sealed bearing 20. Generally, grease is sealed in about 30% of the internal space of the sealed bearing 20. Of course, this grease has a function as a lubricating oil, but it adheres to the lip portions of the oil seals 24, 24 and the minute gaps of the sealed bearing 20, and serves as a sealing agent that closes these minute gaps. It also plays a function.

The ventilation structure 30 includes a ventilation groove 31, an outer ring ventilation hole 32, and a bearing box ventilation hole 33 as main members.

The ventilation groove 31 is a groove formed on a surface of the outer peripheral surface of the outer ring 21 that contacts the bearing mounting surface 12 of the bearing housing 10. The ventilation groove 31 makes a round along the circumferential direction.

The outer ring vent holes 32 are formed at a plurality of locations in the circumferential direction of the outer ring 21. In this example, the outer ring vent holes 32 are formed at equal intervals in a state in which the outer ring 21 makes a round. Each outer ring ventilation hole 32 communicates a space on the inner peripheral side with respect to the outer ring 21 and the ventilation groove 31.

The bearing box vent hole 33 is formed in the bearing box 10 and communicates the outer space outside the bearing box 10 with the ventilation groove 31. The bearing box vent 33 has an inner vent 33a that opens to the vent groove 31, and an outer vent 33b that opens to the external space.

As shown in FIGS. 1A and 1B, the inner vent 33a is positioned at any one of the upper half of the vent groove 31 in a state where the axial direction of the bearing unit 1 (the axial direction of the rotary shaft S) is horizontal. In this example, a bearing box ventilation hole 32 is formed so as to be arranged at the top. The reason for adopting such a position / arrangement is to prevent the inner vent 33a from being blocked by the grease sealed in the internal space of the sealed bearing 20.
Further, the bearing box ventilation hole 32 is formed so that the outer ventilation hole 33b is disposed at a position higher than the inner ventilation hole 33a. The reason for adopting such a position / arrangement is to prevent the grease sealed in the internal space of the sealed bearing 20 from flowing out to the outside through the bearing box vent hole 33.

The air vent 33b of the bearing box vent 33 is provided with a breather 34 that allows air to enter and exit but prevents dust from entering.

In the bearing unit 1 having the above-described configuration, even if the breathing action occurs due to the start / stop of the electric motor or the fluctuation of the outside air temperature, the air entering / leaving with the breathing action is performed by the ventilation structure 30 (the outer ring ventilation hole 32, the ventilation groove). 31 and the bearing box vent hole 33).
This is because the ventilation resistance of the ventilation structure 30 (the outer ring ventilation hole 32, the ventilation groove 31 and the bearing box ventilation hole 33) is extremely small compared to the minute gap of the sealed bearing 20 and the lip portions of the oil seals 24 and 24. It is.

For this reason, even if a breathing action occurs, air does not enter and exit through the minute gaps of the sealed bearing 20 and the lip portions of the oil seals 24, 24. As a result, the grease can be prevented from leaking outside through the minute gap of the sealed bearing 20 and the lip portions of the oil seals 24 and 24.
Therefore, the grease sealed in the sealed bearing 20 can be prevented from being reduced, and the life of the bearing unit 1 can be extended.

[Application Example of Example 1]
In the bearing unit 1 shown in FIG. 1A and FIG. 1B, an example in which grease can be replenished when the grease sealed in the sealed bearing 20 has decreased due to long-term use is an application example of the first embodiment. Will be described.

When the grease can be replenished, not only the breather 34 but also the grease nipple is attached to the outer vent 33b of the bearing box vent 33.

When it becomes necessary to replenish the grease, the breather 34 is removed, and a grease nipple is attached to the portion of the outer vent 33b. Then, the grease gun is inserted into the grease nipple, and the grease is press-fitted toward the bearing box vent hole 33.
Then, the press-fit grease is supplied to the internal space of the sealed bearing 20 through the bearing box ventilation hole 33 → the ventilation groove 31 → the outer ring ventilation hole 32.
Thereby, replenishment of grease becomes possible and the life of the bearing unit 1 can be extended.

Of course, after the grease has been replenished in this way, when the grease sealed in the sealed bearing 20 has decreased again due to long-term use, the grease is similarly introduced into the internal space of the sealed bearing 20 through the grease nipple. Can be replenished.

When the grease is press-fitted with the grease gun, the internal pressure of the sealed bearing 20 is increased by the amount of grease, and the air in the internal space passes through the minute gaps of the sealed bearing 20 and the lip portions of the oil seals 24 and 24. It leaks to the outside, and along with this, the grease also leaks to the outside. However, since the amount leaking to the outside through the lip portion or the like is small compared to the amount of grease to be replenished, this leakage amount is acceptable.

[First Modification of Example 1]
Next, a bearing unit 1a which is a first modification of the first embodiment will be described with reference to FIGS. 2A and 2B.
In the first modification of the first embodiment, the ventilation groove 31 a is formed on the surface of the bearing insertion surface 12 of the bearing housing 10 that contacts the outer peripheral surface of the outer ring 21. That is, in the bearing unit 1 shown in FIGS. 1A and 1B, the ventilation groove 31 is formed on the outer peripheral surface of the outer ring 21, but in the bearing unit 1 a shown in FIGS. 2A and 2B, the ventilation groove 31 a is used as a bearing of the bearing box 10. It is formed on the insertion surface 12.

The outer ring vent hole 32 communicates the space on the inner peripheral side with respect to the outer ring 12 and the vent groove 31a, and the bearing box vent hole 33 communicates the outer space outside the bearing box 10 and the vent groove 31a. Yes.

Since the other parts are the same as those shown in FIGS. 1A and 1B, the same parts are denoted by the same reference numerals, and the description of the overlapping parts is omitted.

Also with the bearing unit 1a which is the first modification of the first embodiment, it is possible to prevent the grease enclosed in the sealed bearing 20 from being reduced and to extend the life of the bearing unit 1.

[Second Modification of Embodiment 1]
Next, a bearing unit 1b which is a second modification of the first embodiment will be described with reference to FIGS. 3A and 3B.
In the sealed bearing 20 of the first embodiment shown in FIGS. 1A and 1B, the rolling elements 23 are rollers, and the sealing members are

oil seals

24 and 24, but the second embodiment of the first embodiment shown in FIGS. 3A and 3B. In the sealed bearing 20b of the modified example, the rolling element 23a is a ball, and the sealing members are

shields

24a and 24a.
In addition, 21a is an outer ring | wheel and 22a is an inner ring | wheel.

Since the other parts including the ventilation structure 30 are the same as those shown in FIGS. 1A and 1B, the same parts are denoted by the same reference numerals, and the description of the overlapping parts is omitted.

Also with the bearing unit 1b which is the second modification of the first embodiment, it is possible to prevent the grease enclosed in the sealed bearing 20a from being reduced and to extend the life of the bearing unit 1.

[Example 2]
4A and 4B show a bearing unit 1c according to a second embodiment of the present invention. FIG. 4A is a cross-sectional view taken along a broken line indicated by a one-dot chain line passing through points A, O, and B in FIG. 4B, and FIG. It is.
This bearing unit 1c is obtained by further adding an oil supply structure 40 to the bearing unit 1 of the first embodiment shown in FIGS. 1A and 1B.
In addition, the same code | symbol is attached | subjected to the same part as what is shown to FIG. 1A and FIG. 1B, and description of the overlapping part is abbreviate | omitted.

The bearing box oil supply hole 41 which becomes the oil supply structure 40 is formed in the bearing box 10, and communicates the outer space outside the bearing box 10 and the ventilation groove 31. The bearing box oil supply hole 41 has an internal oil supply port 41 a that opens to the ventilation groove 31 and an external oil supply port 41 b that opens to the external space.

As shown in FIGS. 4A and 4B, the bearing box oil supply hole 41 is located below the bearing box ventilation hole 33 in a state where the axial direction of the bearing unit 1 (the axial direction of the rotation shaft S) is horizontal. The inner oil supply port 41a is located below the inner ventilation hole 33a, and the outer oil supply port 41b is located below the outer ventilation hole 33b.
The reason for this position and arrangement is that, as will be described later, when grease is supplied to the sealed bearing 20 through the bearing box oil supply hole 41, the grease does not block the ventilation path such as the bearing box ventilation hole 33. This is because of this.

A grease nipple 42 is attached to the outer oil supply port 41 b of the bearing box oil supply hole 41.
Other portions are the same as those of the bearing unit 1 of the first embodiment shown in FIGS. 1A and 1B.

In this bearing unit 1c, even if the breathing action occurs due to the start / stop of the electric motor or the fluctuation of the outside air temperature, the air enters and leaves the breathing action 30 (the outer ring ventilation hole 32, the ventilation groove 31 and the bearing box ventilation). Through hole 33). For this reason, even if a breathing action occurs, air does not enter and exit through the minute gaps of the sealed bearing 20 and the lip portions of the oil seals 24, 24. As a result, the grease can be prevented from leaking outside through the minute gap of the sealed bearing 20 and the lip portions of the oil seals 24 and 24.

Since the grease sealed in the sealed bearing 20 has decreased over many years, when it becomes necessary to replenish the grease, a grease gun is inserted into the grease nipple 42 and the grease is pressed into the bearing box oil supply hole 41. .
Then, the press-fit grease is supplied to the internal space of the sealed bearing 20 through the bearing box oil supply hole 41 → the ventilation groove 31 → the outer ring air supply hole 32 which is close to the inner oil supply port 41 a.
Thereby, replenishment of grease becomes possible and the life of the bearing unit 1 can be extended.

When the grease is replenished in this way, the air in the internal space of the sealed bearing 20 is separated from the internal oil supply port 41a by an amount corresponding to the amount of grease in the internal space of the sealed bearing 20 (more than the internal oil supply port 41a). It is discharged to the outside through the outer ring vent hole 32 → the vent groove 31 → the bearing box vent hole 33 (located above).
Therefore, even if grease is replenished, the pressure in the internal space of the sealed bearing 20 does not increase, and the grease does not leak to the outside through the minute gaps of the sealed bearing 20 or the lip portions of the oil seals 24, 24. Absent.

Of course, after the grease has been replenished in this way, if the grease sealed in the sealed bearing 20 has decreased again due to many years of use, the grease is similarly supplied to the inside of the sealed bearing 20 via the grease nipple 42. The space can be replenished, and the life can be further extended.

Even if the oil supply structure 40 shown in FIGS. 4A and 4B is added to the bearing

units

1a and 1b shown in FIGS. 2A, 2B, 3A, and 3B, it is the same as the bearing unit 1c shown in FIGS. 4A and 4B. An effect can be obtained.

The present invention can be applied to a bearing unit that rotatably supports a rotating shaft of an electric motor or other rotating equipment.

1, 1a, 1b, 1c bearing unit, 10 bearing box, 11 bearing insertion space, 12 bearing mounting surface, 20, 20a sealed bearing, 21, 21a outer ring, 22, 22a inner ring, 23, 23a rolling element, 24 oil seal, 24a shield, 30 vent structure, 31, 31a vent groove, 32 outer ring vent hole, 33 bearing box vent hole, 33a inner vent, 33b outer vent, 34 breather, 40 lubrication structure, 41 bearing box lubrication hole, 41a inner lubrication Mouth, 41b, external refueling port, 42 grease nipple

Claims

In the bearing unit assembled with the sealed bearing inserted in the bearing insertion space formed in the bearing housing,
A ventilation groove, which is a groove that makes a round along the circumferential direction, on a surface that contacts the bearing housing of the outer peripheral surface of the outer ring of the sealed bearing or a bearing mounting surface that contacts the outer peripheral surface of the outer ring of the bearing housing. Formed,
The outer ring is formed with an outer ring ventilation hole that communicates the inner groove side space and the ventilation groove with respect to the outer ring at a plurality of locations in the circumferential direction.
The bearing unit is characterized in that a bearing box ventilation hole is formed in the bearing box to communicate the outer space outside the bearing box with the ventilation groove.
In claim 1,
The bearing box vent has an inner vent opening to the vent groove and an outer vent opening to the outer space, and the inner vent has a round in the circumferential direction. The bearing unit is arranged at any position in the upper half-circumferential portion, and the outer vent is arranged at a position higher than the inner vent.
In claim 1 or claim 2,
The bearing box is formed with a bearing box oil supply hole that communicates the outer space outside the bearing box with the ventilation groove, and the bearing hole oil supply hole is disposed at a position lower than the bearing box ventilation hole. A bearing unit characterized by that.