JPS5915770Y2 - Seal device in bearing device - Google Patents

Description

[Detailed description of the invention] This invention relates to a sealing device for preventing oil leakage in a bearing device.The purpose of the invention is to reliably prevent lubricating oil supplied to the bearing from leaking to the outside. be.

Conventionally, for example, in a bearing device in which a rotary shaft is rotatably supported by a bearing on a support base, and a sealed chamber that is hermetically separated from a chamber that houses a gear mechanism that rotates the rotary shaft is formed on the support base, the bearing In order to prevent the lubricating oil supplied from leaking to the outside, an oil cutting ring with a reverse thread on the outer periphery is fixed to the rotating shaft as a device to seal the rotating shaft. The seal ring is fixed to the support with a gap, and a labyrinth is provided between the gap and the outside for the oil drain ring and the seal ring, and as the rotating shaft rotates, the sealing action of the reverse screw and labyrinth prevents oil leakage. are doing.

However, in this case, the flow of air moving from the gap toward the bearing due to the reverse thread is not smooth due to the influence of the constricted part of the labyrinth, and the internal pressure in the sealed chamber mentioned above is insufficient for the lubrication of the gear mechanism. Since the pressure rises based on the pressure caused by the oil mist supplied, the sealing effect of the reverse thread tends to decrease, resulting in the problem that oil leakage cannot be reliably prevented.

The present invention was made to eliminate these conventional drawbacks, and it creates an air pocket in the seal ring between the gap formed between the reverse thread of the oil cutting ring and the seal ring, and the constriction part that communicates with the outside. The main feature is that this air pocket is communicated with the sealed chamber of the support base to promote air flow due to the reverse thread.

Embodiments of the present invention will be described below with reference to the drawings.

First, 1 is a support stand for a spindle head, etc. in a machine tool, and this support stand 1 has a rotating shaft 2 on which a tool is attached at the tip.
is rotatably supported around a horizontal axis by a bearing 3 such as a rolling bearing.

Furthermore, a sealed chamber 5 is formed in the support base 1 by a sealed lid 4, and this sealed chamber 5 is hermetically separated from a storage chamber that houses an equivalent gear mechanism connected to the rotating shaft 2 and rotated by a drive motor. There is.

An oil cutting ring 6 is fixed to the rotating shaft 2 while supporting the inner ring end surface of the bearing 3, and an O-ring 7 is fitted between the oil cutting ring 6 and the rotating shaft 2.

A labyrinth 8 extending in the axial direction of the rotating shaft 2 and a reverse thread (right-handed in the figure) 9 threaded in the direction opposite to the rotational direction a of the rotating shaft 2 are formed on the outer circumference of the oil cutting ring 6. .

Further, a seal ring 10 is fixed to the tip of the support base 1,
The upper part of the seal ring 10 has one end open to an annular oil receiving chamber 11 formed by the bearing 3, the support base 1, and the seal ring 10 and communicating with the sealed chamber 5, and the other end connected to an oil pump of the same size. A lubricating oil supply path 12 is formed.

A lubricating oil outflow path 13 communicating with the oil receiving chamber 11 is formed in the lower part of the sealing 10, and this outflow path 13 communicates with a discharge hole 14 formed in the support base 1.

Further, a minute gap C is formed between the inner circumferential surface 10a of the seal ring 10 and the reverse thread 9, which communicates with the oil receiving chamber 11.

A notch 15 is recessed in the radial direction on the inner peripheral surface 10a of the seal ring 10 on the bearing 3 side, and a labyrinth 16 is integrally formed on the opposite side of the bearing 3. Labyrinth 8 extends in the axial direction of shaft 2
It is loosely fitted so as to form a constricted portion 17 between the two.

One side of this constricted portion 17 communicates with the gap C, and the other side communicates with the outside.

There is an annular air pocket 18 between the constriction part 17 and the gap C.
Seal ring 1 is located on the opposite side of bearing 3 with reverse thread 9.
This air pocket 18 is engraved on the inner circumferential surface 10a of the seal ring 10, and an air introduction passage 19 bored in the seal ring 10 is communicated with the air pocket 18. It communicates with the sealed chamber 5.

The air introduction passage 19 and the communication passage 20 are provided above the rotating shaft 2 to prevent oil that has lubricated the bearing 3 from entering through the communication passage 20.

Next, the operation of the above configuration will be explained.

Now, when the rotating shaft 2 is rotated in the direction of arrow a through the gear mechanism, oil mist is injected toward the gear mechanism from the jet nozzle of the same rank, and lubricating oil is supplied to the lubricating oil supply path by the operation of the oil pump. 12 to the bearing 3 via the oil receiving chamber 11, and the lubricating oil is supplied from the oil receiving chamber 11 to the lubricating oil outflow path 1.
The lubricating oil that has flowed out into the tank 3 passes through the discharge hole 14 and is collected into an oil tank provided in the support base 1.

At this time, some of the lubricating oil tries to leak through the gap C between the oil cutter ring 6 and the seal ring 10, but
The rotation of the air pocket 18 causes a flow of air from the air pocket 18 side toward the oil storage chamber 11 side, and the sealing action of the reverse screw 9 prevents its leakage.

However, because the pressure caused by the oil mist supplied to the gear mechanism leaks into the sealed chamber 5 and the internal pressure of the sealed chamber 5 increases, a very small amount of the lubricating oil is lost despite the sealing action of the reverse screw 9. The air still tries to leak through the gap C into the air pocket 18.

However, the air in the sealed chamber 5 is guided to the air pocket 18 via the communication passage 20 and the air introduction passage 19, and the pressure is balanced on both sides of the reverse screw 9. Since the lubricating oil is actively and smoothly guided to the inside, even the smallest amount of lubricating oil is reliably prevented from leaking to the outside.

In addition, when the rotation of the rotating shaft 2 is stopped, the oil receiving chamber 1
Although the supply of lubricating oil to 1 is also stopped, the lubricating oil supply passage 1
A small amount of lubricating oil dripping from the seal ring 10 tends to leak out from the end surface 10b of the seal ring 10 along the inner circumferential surface 10a due to the internal pressure generated in the sealed chamber 5, but the air pocket 18 and the oil pan Since the air pressure in the storage chamber 11 is balanced, there is no air flow in the gap C, and since there is a notch 15 in the inner circumferential surface 10a of the sealing 10, the lubricating oil flows through this inner circumferential surface 10a. It will not be transmitted and leaked to the outside.

As described above, in the present invention, a rotary shaft is rotatably supported on a support base by a bearing around a horizontal axis, an oil receiving chamber is formed at one end of the bearing, and lubricating oil is supplied to the bearing. In a bearing device that has a sealed chamber in which internal pressure is generated on the end side, an air pocket is formed between a minute gap formed with a reverse thread and a constriction part that communicates with the outside, and the rotating shaft is inserted into this air pocket. Since the air in the sealed chamber is introduced through the air introduction passage and communication passage provided above the gap, the pressure on both sides of the gap is always balanced regardless of changes in the internal pressure of the sealed chamber. In addition, as the rotating shaft rotates, the reverse thread allows air to actively flow from the air pocket toward the gap, which promotes the sealing effect of the reverse thread and reliably prevents lubricant oil from leaking. It becomes possible to do so.

[Brief explanation of the drawing]

The drawing is a partial cross-sectional view showing an embodiment of the present invention. 1... Support stand, 2... Rotating shaft, 3... Bearing, 5...
... Sealed chamber, 6... Oil drain ring, 9... Reverse thread,
10...Seal nong, 11...Oil receiving chamber, 12.
... Lubricating oil supply path, 17... Throttle portion, 18... Air pocket, 19... Air introduction passage, C... Gap.

Claims (1)

[Scope of utility model registration request] A rotating shaft is rotatably supported on a support base using a bearing, an oil cutting ring that supports the end face of the bearing is fixed to the rotating shaft, a seal ring is fixed to the support base, and the seal ring is fixed to the support base. and one end of the bearing to form an oil receiving chamber in which lubricating oil for lubricating the bearing is supplied, and the oil receiving chamber is hermetically divided inside the support stand on the other end of the bearing to generate internal pressure. In a bearing device having a sealed chamber, a reverse thread threaded in a direction opposite to the rotational direction of the rotating shaft is formed on the outer periphery of the oil cutter ring, and the oil cutting ring is loosely fitted with a slight gap between the oil cutter ring and the reverse thread. The seal ring has an inner circumferential surface formed therein, one end of the gap communicates with the oil receiving chamber, and the other end of the gap has a constricted portion provided between the oil cutting ring and the seal ring. An air pocket is formed in the seal ring between the constricted portion and the other end of the gap, and the air pocket is positioned above the rotating shaft. A sealing device in a bearing device, characterized in that the sealing device communicates with the sealed chamber through an air introduction passage and a communication passage formed in the seal ring and the support base, respectively.