JP2003049849A - Rolling bearing device and main spindle device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing device and a main spindle device for a machine tool capable of easily supplying clean grease while holding the simplification of the structure of a device, or an advantage of grease lubrication. SOLUTION: A housing 14 incorporates a grease feed part 18a, and a pipe part 18b connecting the grease feed part 18a to, at least, a rolling bearing 12 to be lubricated with the grease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing device equipped with a grease supply mechanism and a spindle device for machine tools.

[0002]

2. Description of the Related Art The structure of a conventional rolling bearing device used for a spindle of a machine tool will be described with reference to FIG. A rolling bearing device (spindle device for machine tools) 100 includes a spindle (spindle) 101, a plurality of angular ball bearings (ball bearings) 102 that horizontally rotatably support a front portion of the spindle 101, and a spindle 101. Cylindrical roller bearings (roller bearings) 103 that support the rear part, and these ball bearings 10
2. A housing 104 that covers the outside of the roller bearing 103 is provided. The housing 104 has a cylindrical outer cylinder 105 that surrounds the outer circumferences of the ball bearing 102 and the roller bearing 103, and a front lid 106 and a rear end (which are fixed to the front end (left end in FIG. 4) surface of the outer cylinder 105). The rear lid 107 is fixed to the surface (right end in FIG. 4). Front lid 106
A cover 108 is further attached to the. The outer cylinder 105 has a flange 10 on the front side (the left side in the drawing from the axial center of the spindle 101).
9 is formed. A cooling water spiral groove 110 is formed on the outer peripheral surface of the outer cylinder 105.

Of the plurality of ball bearings 102, the outermost ring 102a of the last ball bearing (the right end in FIG. 4) is locked to the inner diameter step portion 105a of the outer cylinder 105. On the other hand, the outer ring 102 b of the foremost ball bearing has the front cover 106 via the outer ring retainer 111.
Locked in. A cylindrical outer ring spacer 112 is inserted between the outer rings of each ball bearing 102. In this way, the outer ring of each ball bearing 102 is fixed to the inner peripheral surface of the outer cylinder 105.

The inner ring 102c of the frontmost ball bearing is locked to the outer diameter step 101a of the spindle 101. A cylindrical inner ring spacer 113 is inserted between the ball bearings 102. The inner ring 102d of the last ball bearing is the spindle 10
It is locked by the pressing ring 114 fitted in 1, and is pressed in the axial direction. Thus, the inner ring of each ball bearing 102 is integrally rotatably fixed to the outer diameter surface of the spindle 101.

On the other hand, the roller bearing 103 has an outer ring 103.
The front end surface of a is locked to the inner diameter step portion 105b of the outer cylinder 105, the rear end surface is locked to the rear lid 107, and is fixed to the inner peripheral surface of the outer cylinder 105. In addition, the inner ring 1 of the roller bearing 103
03b has its front end face locked to the outer diameter step portion 101b of the spindle 101 via the inner ring spacer 115, and its rear end face is pressed in the axial direction by the pressing ring 116 fitted to the spindle 101, so that the spindle 101 Is integrally rotatably fixed to the outer diameter surface of the.

In the spindle device for machine tools as seen above, the lubrication method for the bearing is oil-air lubrication,
Oil mist lubrication, jet lubrication, grease lubrication and the like can be mentioned. However, oil air and oil mist lubrication generate waste oil, which is an environmental problem. Further, the jet lubrication has a drawback that the structure of the lubrication device is complicated and the driving loss becomes large. On the other hand, grease lubrication is superior in terms of environmental load and structural simplification.

A low temperature rise is desired for bearings for machine tool spindles, and it has been necessary to reduce the amount of grease filled in to less than usual to suppress grease stirring resistance. In addition, it is difficult to replenish a small amount of grease by the usual grease replenishment method, which may impair the low temperature rise property. For this reason, conventional bearings for machine tool spindles that use grease lubrication have a space volume inside the bearing (volume that is the space between the inner ring and the outer ring minus the volume of the balls and cage) when the spindle device is assembled. On the other hand, about 10 to 20% of grease was filled, and it was used without replenishing the grease until the bearing life was reached.

In recent years, the speed of machine tool spindles has increased, and durability has been a problem only with the grease initially filled. Normally, the lubricating life due to grease deterioration is shorter than the rolling fatigue life of the bearing raceway, so it was necessary to replenish the grease before it deteriorated in order to enable continuous use for a longer period of time. However, in order to replenish the grease, it was necessary to disassemble the spindle device, which was troublesome.

For this reason, an external type grease replenisher which does not require disassembly of the main shaft device has been proposed.

[0010]

However, the conventional external type grease replenisher has been concerned about the following points. (1) Since the grease replenisher is outside the spindle device,
The merit of structural simplification unique to grease lubrication diminishes. (2) Since it is attached externally, there is a long pipe section between the grease replenisher and the bearing. If the cleanliness of the piping is poor, the cleanliness of grease cannot be guaranteed. In addition, foreign matter that has entered the inside of the bearing through the piping portion causes rolling fatigue and shortened life. (3) Normally, the housing is provided with a piping hole, but since the housing is large and has a complicated shape, it is difficult to sufficiently clean the piping hole. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rolling bearing device and a spindle for a machine tool, which can easily supply clean grease while maintaining the structural simplification of the device, which is an advantage of grease lubrication. To provide a device.

[0011]

The above object of the present invention can be achieved by the following constitutions. A rolling bearing device in which a rolling bearing is mounted in a housing, the rolling bearing device comprising at least 1
A rolling bearing device, wherein two rolling bearings are lubricated with grease, and a grease supply section is built in the housing. According to such a structure, the grease supply portion is arranged inside the housing, so that the entire rolling bearing device can be downsized. Moreover, the structure is simplified, and repair / replacement can be easily performed. Further, by disposing the grease supply section in the housing, it is possible to shorten the piping section that connects the grease supply section and the rolling bearing, so that it is possible to prevent the rolling fatigue life from being shortened due to the inclusion of foreign matter in the grease. Further, foreign matter is less likely to be clogged in the piping portion, and it is easy to replenish a small amount of grease. In the above configuration, it is preferable that at least the grease supply unit is a detachable cartridge type.
With this configuration, when the grease in the grease supply section is insufficient, only the cartridge needs to be replaced,
It is not necessary to disassemble the spindle device. Therefore, it is extremely easy to refill the grease supply section with grease, and the maintainability is excellent.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a first view of a rolling bearing device (or a machine tool spindle device; hereinafter omitted) of the present invention.
1 illustrates an embodiment. Rolling bearing device 10 of the present invention
The basic configuration is the same as that of the conventional one already described, and only different points will be described below. The same applies to other embodiments.

The outer cylinder 15 of the housing 14 of the rolling bearing device 10 of the present embodiment has an axial hole 16 formed axially from the rear end side (right side in FIG. 1) and a front end of the axial hole 16. A greasing hole 17 that communicates in the radial direction from the portion toward the inner diameter surface of the outer cylinder 15 is formed. A grease replenisher 18 is inserted into the axial hole 16 from the rear end. The grease replenisher 18 is formed in a cartridge type so that it can be removed from the housing when the grease is exhausted. The grease replenisher 18 has a grease storage portion 18a that stores grease and a flexible connecting pipe 18b provided at the front end of the grease storage portion 18a. The connection pipe 18b is inserted into the greasing hole 17, and connects the grease storage portion 18a and the ball bearing 12 that is grease-lubricated. In the present embodiment, the grease storage portion 18a functions as a grease supply portion, and the connection pipe 18b functions as a piping portion. Grease reservoir 18a and connecting pipe 18b
Is contained in the outer cylinder 15 of the housing 14. The outer ring 12a of the ball bearing 12, which is grease-lubricated, has a grease replenishing hole 1 penetrating in the radial direction of the ball bearing 12.
2b is formed to connect the greasing hole 17 and the inside of the ball bearing 12. At the location where the greasing hole 17 opening on the inner diameter surface of the outer cylinder 15 and the outer diameter surface of the ball bearing outer ring 12a are connected, the tip end of the connecting pipe 18b and the grease supply hole 12b are in close contact with each other. The grease stored in the grease storage portion 18a passes through the connecting pipe 18b arranged in the greasing hole 17, and is supplied to the inside of the ball bearing 12 through the grease supply hole 12b. The grease introduced from the grease storage portion 18a into the ball bearing 12 does not contact the inner surface of the housing (the inner surface of the greasing hole).

According to this structure, the grease storage portion 18a and the connecting pipe 18b are built in the housing 14 of the rolling bearing device 10, and the grease does not directly pass through the housing 14. The structure of the entire rolling bearing device 10 is downsized, and clean grease can be supplied to the ball bearings 12. Also, the grease replenisher 1
Since 8 is not provided outside the rolling bearing device 10, it is not necessary to provide extra piping for connecting the grease replenisher 18 and the rolling bearing device 10, and it is possible to prevent foreign matter from entering the grease. Therefore, it is possible to prevent rolling fatigue life from being shortened due to deterioration of grease. further,
Since the grease replenisher 18 is a detachable cartridge type, only the cartridge needs to be replaced when the grease is insufficient. Therefore, the rolling bearing device 10 does not have to be disassembled as a whole, and thus maintainability is excellent.

It should be noted that, as in the present embodiment, not only one ball bearing is replenished with grease, but a plurality of axial holes into which a grease replenisher is inserted are provided while changing the phase,
The structure may be such that grease can be supplied to each ball bearing. Further, the number of piping portions is not limited to one for the grease replenisher, and a plurality of piping portions may be provided so that grease can be supplied to a plurality of ball bearings. However, in order to keep the amount of grease supplied to the ball bearings constant, a cartridge-type grease replenisher corresponding to each ball bearing is provided, and grease is supplied from individual piping parts connected to each grease supply part. It is preferable.
Here, the grease greasing amount is about 0.1 to 4% of the space volume of the ball bearing (volume obtained by subtracting the volume of the ball and the cage from the space formed between the inner ring and the outer ring),
It is possible to lubricate while reducing the influence on the temperature rise of the spindle.

A second embodiment of the rolling bearing device of the present invention will be described with reference to FIG. In the outer cylinder 25 of the housing 24 of the rolling bearing device 20 of the present embodiment, a radial hole 26 that opens in the radial direction from the outer diameter surface side of the outer cylinder 25 and an axial position similar to the radial hole 26 are provided. The greasing hole 27, which has a smaller cross-sectional area than the radial hole 26 and extends in the radial direction, is formed so as to communicate with each other. The greasing hole 27 opens on the inner diameter surface of the outer cylinder 25. A removable cartridge type grease replenisher 28 is inserted into the radial hole 26. The grease replenisher 28 includes a grease storage portion 28a capable of storing grease, and a greasing hole 2 extending from the grease storage portion 28a.
7 and a connecting pipe 28b arranged inside the same. The grease storage portion 28 a and the connection pipe 28 b are built in the outer cylinder 25 of the housing 24. The grease storage portion 28a
Does not protrude from the outer diameter surface of the outer cylinder 25. In this embodiment, the grease storage portion 28a functions as a grease supply portion, and the connection pipe 28b functions as a piping portion. Outer cylinder 25
At the point where the greasing hole 27 opening on the inner diameter surface of the ball bearing and the outer diameter surface of the ball bearing outer ring 12a are connected, the tip of the connecting pipe 28b and the grease supply hole 12b are in close contact with each other.

With this structure, it is easy to bring the tip of the connecting pipe 28b into close contact with the grease supply hole 12b. Further, since the grease supply portion can be inserted not only in the axial direction but also in the radial direction, the degree of freedom in designing the rolling bearing device is improved.

A third embodiment of the rolling bearing device of the present invention will be described with reference to FIG. The outer cylinder 35 of the housing 34 of the rolling bearing device of the present embodiment has an axial hole 36 formed axially from the rear end side and a radial hole formed radially from the outer diameter surface of the outer cylinder 35. And 37 are formed. Here, the front end portion of the axial hole 36 is structured to communicate with the radial hole 37. A grease replenisher 38 is inserted into the axial hole 36 from the rear end side. Grease replenisher 3
8 has a detachable cartridge type grease supply portion 38a for storing grease. Grease supply section 3
A greasing port 38b is provided at the front end of 8a. On the rear end side of the grease supply portion 38a of the grease replenisher 38,
The grease greasing means 33 is inserted. Examples of the grease supply unit 33 include a unit that pushes out grease by pushing a piston with a cylinder that uses air pressure or gas pressure. The greasing nozzle piece 32 is inserted into the radial hole 37 from the outer diameter surface side of the outer cylinder 35. Inside the greasing nozzle piece 32, a piping portion 32a is provided, one of which communicates with the greasing port 38b and the other of which communicates with the grease supply hole 12b of the ball bearing 12. Therefore, the grease supply unit 3
8a and the piping part 32a are built in the housing 34.

At the time of supplying grease, the grease flows by the grease supply means 33 from the grease supply port 38b of the grease supply section 38a to the pipe section 32a, and the grease supply hole 1
It is supplied to the inside of the ball bearing 12 via 2b.

With this structure, the same effect as that of the first embodiment can be obtained. Further, by using the grease replenisher 38 and the greasing nozzle piece 32 together, the pipe 32
It is possible to increase the degree of airtightness in a and stabilize the amount of greasing. Further, the degree of adhesion between the pipe portion 32a of the greasing nozzle piece 32 and the ball bearing outer ring 12a can be improved.

As shown in the above embodiment, the removable cartridge type grease supplying portion is shown to be inserted in the axial direction and the one which is inserted in the radial direction. However, not only can the volume of grease in the cartridge be increased, but also the cartridge can be replaced easily.

The present invention is not limited to the above-described embodiment, but can be appropriately modified and improved. For example, by providing a filter mechanism at an appropriate position such as a pipe portion, it is further effective to prevent foreign matter from entering the grease supplied to the inside of the rolling bearing. It is also conceivable to directly fill the axial holes with grease. In this case, the axial hole functions as a grease supply unit.

[0023]

As described above, according to the present invention,
It is possible to provide a rolling bearing device and a machine tool spindle device that can easily supply clean grease while maintaining the structure simplification of the device, which is an advantage of grease lubrication.

[Brief description of drawings]

FIG. 1 is a rolling bearing device according to a first embodiment of the present invention.

FIG. 2 is a rolling bearing device according to a second embodiment of the present invention.

FIG. 3 is a rolling bearing device according to a third embodiment of the present invention.

FIG. 4 is a conventional rolling bearing device.

[Explanation of symbols]

10, 20, 30 Rolling bearing device 12 ball bearings 12a Ball bearing outer ring 12b Grease supply hole 14, 24, 34 housing 15, 25, 35 Outer cylinder 18, 28, 38 Grease replenisher 18a, 28a grease reservoir 18b, 28b connecting pipe 32 greasing nozzle piece 32a Piping section 38a Grease supply section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Morita             1-5-50 Kumei, Kugenuma, Fujisawa-shi, Kanagawa             Within NSK Ltd. F-term (reference) 3C011 FF06                 3C045 FD12 FD18                 3C048 AA07 CC04 DD13 EE02                 3J101 AA02 AA32 AA42 AA54 AA62                       BA77 CA01 CA14 EA63 FA48                       FA55 GA31

Claims (4)

[Claims] 1. A rolling bearing device in which a rolling bearing is mounted in a housing, wherein at least one rolling bearing is lubricated with grease, and a grease supply section is built in the housing. Bearing device. 2. The grease-lubricated rolling bearing comprises:
The rolling bearing device according to claim 1, wherein the outer ring has a grease supply hole, and the grease supply portion communicates with the grease supply hole. 3. The grease supply unit is at least a removable cartridge type.
Alternatively, the rolling bearing device according to item 2. 4. A spindle device for machine tools, wherein a rolling bearing supporting a spindle is mounted in a housing, wherein at least one rolling bearing is lubricated with grease, and a grease supply section is built in the housing. A spindle device for machine tools characterized in that