JPH0611743Y2 - Jet lubrication spindle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a jet lubrication spindle used for a spindle of a machine tool or the like, and more particularly to improvement of a seal mechanism of the jet lubrication spindle.

(Prior Art) Generally, in the lubrication of a jet lubrication spindle, lubricating oil is supplied to a bearing from a lubricating oil supply port, and most of the lubricating oil after lubrication is forcibly sucked from the lubricating oil discharge port to the outside of the spindle. Is discharged. A labyrinth portion is provided near the lubricating oil supply port and the discharging port to seal the lubricating oil so that the lubricating oil does not leak to the atmosphere at both ends of the spindle.

(Problems to be solved by the device) However, even if the seal is applied as described above, it may still be insufficient, and it was not possible to completely prevent the lubricating oil from leaking into the atmosphere. .

Therefore, in order to solve such a problem, in the conventional jet lubrication spindle, the seal portions X and Y shown by broken lines in FIG. 1 are sealed as follows. Incidentally, since the seal portions X and Y are usually sealed in substantially the same manner without a large difference in structure, only the seal portion X will be described here for convenience.

(A) The sealing effect is enhanced by simply complicating the labyrinth portion without performing air sealing.

(B) It is an enlarged cross-sectional view of the X part in FIG. 1, and as shown in FIG. 3 showing a conventional example, an air seal is applied and the air pressure is used for sealing.

However, the following two problems remain in the above two measures. First, in the method (a), the labyrinth portion of the seal portion is complicated, so that it is possible to seal the lubricating oil, but since air sealing is not performed, the spindle oil penetrates into the spindle device from outside the spindle device. Since foreign matter (metal dust, cutting oil, foreign matter such as dust, simply referred to as “foreign matter” hereinafter) cannot be completely sealed, even if the seal against the lubricating oil is sufficient, the foreign matter will enter the main shaft and May be prematurely damaged.

Next, in the case of (b), since the air seal is applied, foreign matter entering from the outside into the spindle device can be sealed. However, in this case, the sealing of the lubricating oil may be insufficient. This will be described with reference to FIG.

An air flow F ′ supplied from an air introduction port 33 provided in a housing 32 surrounding a spindle 31 of a spindle supported by a bearing 36 is axially bisected by an air pocket 34, one of which is from the air pocket 34 to the spindle. It flows as an air flow B'outside the device. The other is the air pocket 34.
To the inside of the spindle device as an air flow A '.

Comparing the air flow A ′ and the air flow B ′, in the case of the air flow B ′, the air flows more easily than the air flow A ′ because it is open to the atmosphere. Therefore, most of the air supplied to the air pocket 34 is the air flow B ′ outside the spindle device,
That is, since the oil flows into the atmosphere, the lubricating oil after lubricating the bearings does not remain in the oil pocket 35, but the air pocket 3
4, the lubricating oil after the invasion is conveyed by the air flow B ', and leaks to the outside of the spindle device. As a result, there is a risk that the lubricating oil may leak and cause atmospheric pollution.

Therefore, an object of the present invention is to provide a jet lubrication spindle which prevents the leakage of lubricating oil from the spindle device and the invasion of foreign matter into the spindle device from the outside, resulting in an improved bearing life and no risk of atmospheric pollution. That is.

(Means for Solving Problems) In order to achieve the above-mentioned object, the jet lubrication spindle of the present invention has a main shaft (1) and rolling bearings (2) having inner rings fixed to the outer circumferences of both ends thereof. In a jet lubrication spindle (20), which comprises a main spindle device and a housing (5) that supports the outer ring of the bearing and surrounds the main spindle device, and is jet-lubricated by a lubricating oil, in a radial direction penetrating the housing. Air introduction passage (12) that reaches the main shaft and introduces compressed air from the outside
And an air pocket (13) defined between the air pocket and the main shaft with the air introduction passage open, and a space on the side of the air pocket and the rolling bearing that is arranged between the air pocket and the rolling bearing. The oil pocket (1
4) and a labyrinth portion (16) provided in a path opening from the air pocket to the shaft end, and the oil pocket has a suction passage (1) penetrating the housing in the radial direction.
7) is connected, and a pump (19) forcibly sucking the lubricating oil in the oil pocket and discharging it to the outside of the spindle device is connected to the suction passage.

(Operation) According to the jet lubrication spindle of the present invention having the above-described configuration, the oil pocket is provided with the lubricating oil suction passage, so that the pump sucks a slight negative pressure. In addition, a billing portion is formed outside another air pocket, and the resistance of the air flow toward the bearing side is greater than that of the air flow toward the labyrinth side. Lubricating oil, which becomes large and leaks from the bearing direction to the outside without flowing into the air pocket, is forcibly sucked before entering the air pocket. Prevents leakage to the outside through the oil pocket and labyrinth part.

Embodiment An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same parts are designated by the same reference numerals.

FIG. 1 is an axial sectional view showing an embodiment of the jet lubrication spindle of the present invention. The jet lubrication spindle 20 that is jet lubricated with lubricating oil is shown with one end in the axial direction omitted. Jet lubrication spindle 2
Reference numeral 0 denotes a known spindle used for machine tools such as machining centers.

A rolling bearing such as an angular bearing, that is, an inner ring of the bearing 2 is fixed to the outer periphery of the main shaft 1. Therefore,
The main shaft 1 is rotatably supported by a plurality of bearings 2 provided at predetermined intervals in the axial direction. The outer ring of the bearing 2 is supported by a housing 5 having a front lid arranged so as to surround the main shaft 1. Between the axial direction of the bearing 2, spacers 3 and 4 are in contact with the bearing 2 and fitted on the outer periphery of the main shaft 1.

The housing 5 has a lubricating oil inlet 6 and a lubricating oil outlet 8
Are provided and communicate with the respective lubricating oil passages 7 extending in the axial direction. The lubricating oil passage 7 has a plurality of lubricating oil ejection passages 7a for jet lubricating the bearing 2 via the spacers 40 and 41. Most of the lubricating oil that has lubricated the bearing 2 is discharged from the discharge port 8 through the lubricating oil passage 21, but part of the lubricating oil leaks in the axial direction toward the shaft end portion.
For this reason, seal portions X and Y are provided at both axial end portions of the main shaft 1 so that lubricating oil after bearing lubrication does not leak in the axial direction. In practice, the seal portions X and Y have almost the same structure, so only the seal portion X will be described here.

FIG. 2 is an enlarged sectional view of the seal portion X. Seal part X
In the vicinity of the housing 5, an air introduction passage 12 having an air introduction port 11 for introducing compressed air having a predetermined pressure from an air supply source (not shown) penetrates the front lid of the housing 5 in the radial direction from the outer periphery thereof. It extends to the spindle 1. The air introduction passage 12 defines an air pocket 13 between itself and the main shaft 1. A first oil pocket 14 is provided near the bearing 2 in the axial direction, and a second oil pocket 14 is provided on the side opposite to the bearing 2. The pockets 15 communicate with each other through narrow gaps. The second oil pocket 15 further communicates with the labyrinth portion 16 in the axial direction, and communicates with the outside of the spindle device via the labyrinth portion 16.

The first oil pocket 14 extends through the front lid of the housing 5 in the radial direction and communicates with a discharge passage 17 for discharging leaked lubricating oil having a discharge port 18 on its outer periphery. The discharge passage 17 is connected to the pump 19, and the pump 19
The lubricant oil is sucked in by and is discharged to the outside of the spindle device.

The jet lubrication spindle 10 of the present invention constructed as described above prevents the leakage of lubricating oil and the intrusion of foreign matter from the outside, as described below. The air flow F that has entered from the air introduction passage 12 that functions as an air seal has an air flow A that enters the first oil pocket 14 when it reaches the air pocket 13, and an air flow B that enters the second oil pocket 15. Divert to. The air flow B passes through the labyrinth portion 16 and escapes to the outside of the spindle device, that is, to the atmosphere. Air flow A
Provides an axial pressing force so that the lubricating oil that enters the first oil pocket 14 and leaks from the bearing direction does not leak to the outside of the spindle device. However, as already described, with this configuration as it is, the pressure of another oil pocket 14 becomes high and the flow rate of the air flow A becomes small, so that the air entering from the air introduction passage 12 becomes almost the air flow B. It escapes to the outside, and the air sealing effect cannot be fully achieved.

However, the first oil pocket 14 is provided with the lubricating oil discharge passage 17, which is sucked by the pump 19 so as to apply a slight negative pressure, and the labyrinth portion 16 is provided outside the second air pocket. Is formed and the resistance to the air flow B is made larger than that of the air flow A, so that the flow rate of the air flow A becomes large and the lubricating oil does not flow into the air pocket 13 and tries to leak to the outside from the direction of the bearing 2. Since the lubricating oil is forcibly sucked before entering the air pocket 13, the lubricating oil after lubrication can be prevented from passing through the air pocket 13, the oil pocket 15 and the labyrinth portion 16 and leaking to the outside. If the suction force by the pump 19 is set to an appropriate value with respect to the air flow A, the flow of the air flow A is assisted and the sealing effect is further increased.

The embodiment of the present invention described above is merely one example of the present invention, and various changes and modifications can be made without departing from the scope of the technical idea of the present invention.

(Effect of the Invention) According to the jet lubrication spindle of the present invention described above, the following effects can be obtained.

Conventionally, it is possible to achieve at the same time the sealing of lubricating oil, which was difficult to achieve at the same time, and the prevention of foreign matter from entering from the outside at the same time.

Therefore, the bearing is not prematurely damaged and the life of the bearing is extended. In addition, atmospheric pollution due to leakage of lubricating oil can be prevented.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a spindle showing an embodiment of the present invention, FIG. 2 is an enlarged view of a seal portion X of FIG. 1, and FIG. 3 shows a conventional seal portion. FIG. [Explanation of symbols of main parts] 1 ... spindle 2 ... bearing 5 ... housing 12 ... air passage 13 ... air pockets 14,15 ... oil pocket 17 ... discharging passage 19 ... pump

Claims (1)

[Scope of utility model registration request] Claims: 1. A main shaft device having a main shaft and a rolling bearing having inner rings fixed to the outer circumferences of both ends thereof, and a housing for supporting the outer ring of the bearing and surrounding the main shaft device. In a jet lubrication spindle to be lubricated, an air introduction passage that penetrates the housing in the radial direction to reach the main shaft and introduces compressed air from the outside,
An air pocket which is opened between the air introduction passage and the main shaft, and an air pocket which is arranged between the air pocket and the rolling bearing and has a narrow gap in a space lateral to the air pocket and the rolling bearing. And a labyrinth portion provided in a path opening from the air pocket to the shaft end, and a suction passage radially extending through the housing is connected to the oil pocket. A jet lubrication spindle, wherein a pump for forcibly sucking the lubricating oil therein and discharging it to the outside of the main spindle device is connected to the suction passage.