JPH09329143A - Spindle device - Google Patents

Abstract

(57) [PROBLEMS] To prevent a fluid leaking from a slide bearing from flowing out of the device and a foreign substance from entering the device, and to reduce manufacturing cost and improve rigidity of a spindle. A main shaft (2), a housing (3), and an oil bearing (4) that supports the main shaft (2) in a radial direction in a non-contact state are provided, and a part of the main shaft (2) closer to the shaft end (2a) than a part facing the oil bearing (4), An annular projection 11 having an end face 11a facing the shaft end 2a side of the main shaft 2 and an end face 11b facing the oil bearing 4 side is provided concentrically with the main shaft 2, and the housing 3 is compressed by a compressed gas supply source P. Shaft end side injection port 1 for blowing air to the end faces 11a, 11b of the annular projection 11 in the axial direction
2A and the oil bearing side injection port 12B are provided to form the air thrust bearing 10, and between the main shaft 2 and the housing 3,
A shaft end side outflow passage 6A and an oil bearing side outflow passage 6B for letting out compressed air from the air thrust bearing 10 toward the shaft end 2a of the main shaft 2 and the oil bearing 4 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device in which a spindle is supported in a radial direction in a non-contact state by a slide bearing,
For example, it relates to a spindle device used in a machine tool.

[0002]

2. Description of the Related Art Conventionally, as the above-described main spindle device, for example, there is one shown in FIG. 6, and as shown in FIG. 6, the main spindle device 101 includes a main spindle 102 and a housing 103 for accommodating the main spindle 102. A slide bearing 104 is provided in the housing 103 to support the main shaft 102 in the non-contact state in the radial direction.

In this spindle device 101, the housing 10
3, a plurality of annular grooves 10 are provided in a portion facing the small diameter portion 102a located on one end side (the left end side in the drawing) of the main shaft 102.
3a is provided to form the labyrinth seal 105 between the plurality of annular grooves 103a and the main shaft 102, and the housing 103 is provided with a communication hole 103b between the labyrinth seal 105 and the outside.
Lubricating oil from the slide bearing 104 and foreign matter from one end of the main shaft 102, which have entered the 05, are allowed to flow out to a collecting portion (not shown) provided outside the housing 103 through the communication hole 103b. In this case, the first taper portion 102b having a diameter gradually increasing from one end side to the other end side of the main shaft 102 at a portion facing the communication hole 103b of the main shaft 102 forming the labyrinth seal 105 together with the plurality of annular grooves 103a. Also, a second taper 102c having an inclination direction opposite to that of the first taper portion 102b is provided to facilitate the movement of the lubricating oil and the foreign matter which receive the centrifugal force to the communication hole 103b.

[0004]

However, in the above-described conventional main spindle device 101, the lubricating oil of the slide bearing 104 leaks to the outside of the device, and a foreign substance enters from the one end side of the main shaft 102 into the inside of the device. In order to surely prevent the above, it is necessary to make both the main shaft 102 and the labyrinth seal constituting portion of the housing 103 into complicated shapes,
There is a problem that the manufacturing cost becomes higher by that amount.

In addition, the main shaft 102 and the housing 10
When the labyrinth seal component of 3 is complicated,
Since the length (the distance from the slide bearing 104 to the shaft end) of the small-diameter portion 102a as the shaft end of the main shaft 102 has to be long for the sake of design, there is a problem that the rigidity of the main shaft decreases. Therefore, it has been a conventional problem to solve these problems.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. The fluid leaking from the sliding bearing (oil when the sliding bearing is an oil bearing) flows out of the apparatus and foreign matter. It is an object of the present invention to provide a spindle device that surely prevents the intrusion into the inside of the device, reduces the manufacturing cost, and improves the rigidity of the spindle.

[0007]

The invention according to claim 1 of the present invention comprises a main shaft, a housing for accommodating the main shaft,
In a main spindle device provided with a slide bearing provided in the housing to support the main spindle in a radial direction in a non-contact state, the main spindle is compressed gas in a portion closer to a shaft end than a portion of the main spindle facing the slide bearing. By providing a gas thrust bearing that supports the thrust direction in a non-contact state, the compressed gas is allowed to flow from the gas thrust bearing toward the shaft end of the main shaft and the slide bearing through the space between the main shaft and the housing. The main feature of the present invention is that the structure of the spindle device serves as a means for solving the conventional problems.

The invention according to claim 2 of the present invention is
In a main spindle device including a main shaft, a housing that accommodates the main shaft, and a slide bearing that is provided in the housing and supports the main shaft in a radial direction in a non-contact state, a shaft that is located in a portion of the main shaft that faces the slide bearing. At a portion near the end, a pressure receiving portion having a shaft end side pressure receiving surface facing the shaft end side of the main shaft and a bearing side pressure receiving surface facing the slide bearing side is provided concentrically with the main shaft, and the housing is provided with compressed gas. A shaft end side injection port and a slide bearing side injection port for blowing the compressed gas supplied from the supply source in the axial direction to the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the pressure receiving portion are provided, and the main shaft is compressed gas. To form a gas thrust bearing that is supported in the thrust direction in a non-contact state with the main shaft and the housing from the gas thrust bearing to the shaft end of the main shaft and the slide bearing. Only has a feature that it has a structure provided with each outflow is to the shaft end side outflow passage and sliding bearing side outflow passage compressed gas with, and the structure of the spindle device and means for solving the conventional problems.

Further, the spindle device according to claim 3 of the present invention is configured such that the slide bearing side outflow passage communicates with a compressed gas recovery passage provided in the housing, and the spindle device according to claim 4 of the present invention comprises: The housing is provided with a discharge passage for discharging the compressed gas from the gas thrust bearing to the outside, and in the spindle device according to claim 5 of the present invention, the pressure receiving portion is an annular projection portion formed concentrically with the spindle. The shaft end side pressure receiving surface and the bearing side pressure receiving surface are both end surfaces of the protrusion orthogonal to the main shaft, and the main shaft device according to claim 6 of the present invention is the shaft end side pressure receiving surface of the housing. An annular groove is provided on the surface opposite to the bearing-side pressure receiving surface so that the compressed gas ejected from the shaft end side injection port and the sliding bearing side injection port flows in the circumferential direction of the main shaft.

Furthermore, in the spindle device according to a seventh aspect of the present invention, the shaft end side pressure receiving surface and the bearing side of the pressure receiving portion are located closer to the main shaft than the shaft end side injection port and the sliding bearing side injection port of the housing. A shaft end side auxiliary injection port and a slide bearing side auxiliary injection port for blowing the compressed gas supplied from the compressed gas supply source to the pressure receiving surface in the axial direction are provided, and the shaft end side auxiliary injection port and the slide bearing side auxiliary injection port are provided. The pressure of the compressed gas ejected from the shaft end side injection port and the pressure of the compressed gas ejected from the slide bearing side injection port are set lower than the pressure of the compressed gas ejected from the shaft end side injection port and the slide bearing side injection port. The diameter of each of the injection port and the slide bearing side auxiliary injection port is made smaller than the diameter of each of the shaft end side injection port and the slide bearing side injection port, so that the shaft end side auxiliary injection port and the slide bearing side auxiliary injection The pressure of the compressed gas ejected from the shaft is set lower than the pressure of the compressed gas ejected from the shaft end side injection port and the slide bearing side injection port, and in the main shaft device according to claim 9 of the present invention, Annular auxiliary grooves are provided on the opposing surfaces facing the end-side pressure receiving surface and the bearing-side pressure receiving surface, respectively, so that compressed gas ejected from the shaft-end-side auxiliary injection port and the sliding bearing-side auxiliary injection port flows circumferentially. The space volume between the groove and the pressure receiving part is wider than the space volume between the annular groove and the pressure receiving part that allows compressed gas ejected from the shaft end side injection port and the slide bearing side injection port to flow in the circumferential direction of the main shaft. Then, the pressure of the compressed gas ejected from the shaft end side auxiliary injection port and the slide bearing side auxiliary injection port is made lower than the pressure of the compressed gas ejected from the shaft end side injection port and the slide bearing side injection port. Are

Further, according to a tenth aspect of the present invention, a spindle device is located between the annular groove and the annular auxiliary groove on the surface of the housing facing the shaft end side pressure receiving surface and the bearing side pressure receiving surface, respectively. As a result, an annular discharge groove for discharging compressed gas is provided outside the gas thrust bearing.

[0012]

In the spindle device according to the first aspect of the present invention, the compressed gas flowing from the gas thrust bearing toward the slide bearing through the space between the spindle and the housing is a fluid leaking from the slide bearing (the slide bearing is an oil bearing). Oil) to flow toward the shaft end side of the main shaft, while compressed gas flowing from the gas thrust bearing toward the shaft end of the main shaft through the space between the main shaft and the housing is a foreign substance from the shaft end of the main shaft. Therefore, the fluid leaking from the slide bearing is reliably prevented from flowing out of the device and foreign matter from entering the device.

That is, since the gas thrust bearing also has a sealing function, the sealing structure is simple, and in comparison with the case where the thrust bearing and the labyrinth seal are individually provided, the sliding bearing and the shaft are not provided. The distance to the end is shortened, so that the manufacturing cost is reduced and the spindle rigidity is improved.

In the spindle device according to the second aspect of the present invention, the compressed gas supplied from the compressed gas supply source passes through the shaft end side injection port of the gas thrust bearing and the slide bearing side injection port, and the shaft end of the pressure receiving portion. Axial to side pressure receiving surface and bearing side pressure receiving surface (orientated with an axial component)
Respectively, are sprayed on the main shaft in the thrust direction, and flow toward the shaft end of the main shaft and the slide bearing while supporting the main shaft in the thrust direction. The leakage of fluid from the bearing to the outside of the device and the intrusion of foreign matter into the device will be reliably prevented.At this time, in addition to simplifying the sealing structure, the sliding bearing to the shaft end The distance is shortened, so that the manufacturing cost can be reduced and the spindle rigidity can be improved.

In the spindle device according to the third aspect of the present invention, the compressed gas flowing from the gas thrust bearing toward the slide bearing through the slide bearing side outflow passage is the fluid leaking from the slide bearing to the shaft end side of the spindle. The fluid leaking from the plain bearing flows into the compressed gas recovery passage together with the fluid leaking from the plain bearing, so that the fluid leaking from the plain bearing is more reliably prevented from flowing out of the device from between the spindle and the housing. In the spindle device according to claim 4 of the present invention, the compressed gas supplied through the shaft end side injection port and the slide bearing side injection port is discharged from the gas thrust bearing to the outside (centrifugal direction) through the discharge passage. Therefore, excessive rise of the pressure in the gas thrust bearing is avoided without impairing the bearing function.

In the spindle device according to claim 5 of the present invention,
When compressed gas is blown in the axial direction from the shaft end side injection port and the sliding bearing side injection port to both end faces of the protrusion as a pressure receiving part that is orthogonal to the main axis, the direction at the pressure receiving part is reversed and large. The axial velocity component having the same value is efficiently generated, so that the main shaft is supported without rattling in the axial direction. In the main spindle device according to claim 6 of the present invention, the shaft end side injection port and the slip The compressed gas ejected from the bearing side injection port flows in the circumferential direction of the main shaft along the annular groove, so the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the pressure receiving portion, and the shaft end side pressure receiving surface and the bearing of the housing The pressure distribution between the opposing surface facing the side pressure receiving surface becomes uniform in the circumferential direction, and as a result, the main shaft is supported without tilting with respect to the gas thrust bearing.

In the spindle device according to claim 7 of the present invention,
When compressed gas is blown from the shaft end side injection port and the sliding bearing side injection port to the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the pressure receiving part, the main shaft is supported in the thrust direction. When a compressed gas of lower pressure than the compressed gas is blown from the auxiliary injection port and the sliding bearing side auxiliary injection port onto the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the pressure receiving part, the shaft end side auxiliary injection port and the sliding bearing side auxiliary injection Since the port is located closer to the main shaft than the shaft end side injection port and the sliding bearing side injection port, low pressure compressed gas passes through the bearing side outflow passage and the sliding shaft end side outflow passage and The fluid flowing toward the slide bearing and leaking from the slide bearing is prevented from flowing out of the device and foreign matter from entering the inside of the device, and thus, the shaft end side injection port and the slide bearing side injection port are prevented. Both the thrust bearing function and the sealing function are enhanced by using the compressed gas ejected for bearings and the compressed gas ejected from the shaft end side auxiliary injection port and the sliding bearing side auxiliary injection port for sealing. .

In the spindle device according to claim 8 of the present invention,
The pressure of the compressed gas ejected from the shaft end side auxiliary injection port and the sliding bearing side auxiliary injection port is easily lowered. In the spindle device according to claim 9 of the present invention, the shaft end side auxiliary injection port and the sliding bearing side auxiliary are provided. The pressure of the compressed gas ejected from the injection port is easily lowered, and the flow rate of the compressed gas is increased by the amount that the space volume between the annular auxiliary groove and the pressure receiving portion is wider than the space volume between the annular groove and the pressure receiving portion. As a result, the sealing function will be further improved.

In the spindle device according to the tenth aspect of the present invention, since the pressure on the annular groove side partitioned by the annular discharge groove and the pressure on the annular auxiliary groove side do not affect each other, the thrust bearing function and the sealing function are achieved. Both will be improved.

[0020]

The spindle device according to the first and second aspects of the present invention has the above-described structure, and therefore, the seal structure is not complicated and the distance from the plain bearing to the shaft end is not lengthened. Since it is possible to reliably prevent the fluid leaking from the slide bearing from flowing out of the device and the foreign matter from entering the device, it is possible to reduce the manufacturing cost and improve the spindle rigidity. Excellent effect is brought about.

Further, in the spindle device according to claim 3 of the present invention, in addition to the same effects as those of the spindle device according to claims 1 and 2, the compressed gas flowing from the gas thrust bearing toward the slide bearing is obtained. However, since it flows into the compressed gas recovery passage together with the fluid leaking from the slide bearing, it is possible to more reliably prevent the fluid leaking from the slide bearing from flowing out of the device. In the main shaft device, the compressed gas is discharged from the gas thrust bearing to the outside through the discharge passage, so it is possible to suppress the pressure of the gas thrust bearing from becoming higher than necessary without affecting the thrust bearing function. Excellent effect is brought about.

Further, in the spindle device according to the fifth aspect of the present invention, since a large axial velocity component can be applied to the pressure receiving portion, the spindle can be supported without rattling in the axial direction. Therefore, in the spindle device according to claim 6 of the present invention, between the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the pressure receiving portion and the facing surface facing the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the housing. Since the pressure distribution can be made uniform in the circumferential direction, a very excellent effect that the main shaft can be supported without tilting with respect to the gas thrust bearing is brought about.

Furthermore, in the spindle device according to claim 7 of the present invention, the same effects as those of the spindle device according to claims 1 and 2 are obtained, and in addition, jetting is made from the shaft end side injection port and the slide bearing side injection port. The compressed gas supports the main shaft in the thrust direction, and the compressed gas ejected from the shaft end side auxiliary injection port and the sliding bearing side auxiliary injection port leaks from the slide bearing to the outside of the device and foreign matter into the device. Since it prevents the intrusion of water, it has an extremely excellent effect that both the thrust bearing function and the sealing function can be improved.

Furthermore, in the spindle device according to the eighth aspect of the present invention, the pressure of the compressed gas ejected from the auxiliary injection port on the shaft end side and the auxiliary injection port on the sliding bearing side can be lowered with a simple structure. The spindle device according to claim 9 has the same effect as the spindle device according to claim 8, and in addition to the compressed gas for preventing the leakage of fluid leaking from the slide bearings to the outside of the device and the intrusion of foreign matter into the device. Since the flow rate can be increased, the sealing function can be further improved. In the spindle device according to the tenth aspect of the present invention, the pressure on the annular groove side and the pressure on the annular auxiliary groove side partitioned by the annular discharge groove are mutually increased. Since they can be prevented from interfering with each other, the thrust bearing function and the sealing function can both be improved, which is a very excellent effect.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 shows claims 1 to 3 of the present invention.
6 shows an example of a spindle device according to No. 6.

As shown in FIG. 1, the main spindle device 1 includes a main spindle 2, a housing 3 for accommodating the main spindle 2, and an oil bearing provided in the housing 3 for supporting the main spindle 2 in a radial direction in a non-contact state. (Slide bearing) 4 and an air thrust bearing (gas thrust bearing) 10 at a portion closer to the shaft end 2a than a portion of the main shaft 2 facing the oil bearing 4 (a portion closer to the left end in the drawing). There is.

The air thrust bearing 10 is provided concentrically with the main shaft 2 and has annular projections (pressure receiving parts) in which end surfaces 11a and 11b as shaft end side pressure receiving surfaces and bearing side pressure receiving surfaces are orthogonal to the main shaft 2. 11, a shaft end side injection port 12A and an oil bearing which are provided in the housing 3 and communicate with the compressed gas supply source P via the supply paths 5A and 5B, respectively, and face both end surfaces 11a and 11b of the annular projection 11 respectively. Side injection port 12
B and both end surfaces 1 of the annular protrusion 11 in the housing 3
Annular grooves 13A, 13B which are respectively provided on the facing surfaces 3a, 3b facing the 1a, 11b along the circumferential direction and communicate with the shaft end side injection port 12A and the oil bearing side injection port 12B.
And the compressed air (compressed gas) supplied through the supply paths 5A, 5B from the shaft end side injection port 12A and the oil bearing side injection port 12B to both end faces 11a of the annular protrusion 11a.
11b is blown in the axial direction and the annular groove 13
A in the circumferential direction of the spindle 2 along the A, 13B, the spindle 2
Is supported by compressed air in a non-contact state in the thrust direction.

In this case, between the main shaft 2 and the housing 3, a shaft end side outflow passage 6A and an oil bearing for letting out compressed air from the air thrust bearing 10 toward the shaft end 2a of the main shaft 2 and the oil bearing 4, respectively. A side outflow passage 6B is provided, and between the oil bearing 4 and the air thrust bearing 10 is communicated with both the oil bearing side outflow passage 6B and a compressed air recovery portion (not shown) and lubricating oil for the oil bearing 4 is provided. And air thrust bearing 10
The compressed air recovery passage 7 kept at a pressure lower than that of the compressed air is provided, while the compressed air supplied to the air thrust bearing 10 is provided at a portion of the housing 3 located in the centrifugal direction of the air thrust bearing 10. A discharge path 8 for discharging the material to the outside of the apparatus is provided.

In the main spindle device 1, compressed air supplied from the compressed gas supply source P via the supply paths 5A and 5B is annularly supplied from the shaft end side injection port 12A and the oil bearing side injection port 12B of the air thrust bearing 10. Both end surfaces 11 of the protrusion 11
When it is blown to a and 11b in the axial direction and flows in the circumferential direction of the main shaft 2 along the annular grooves 13A and 13B, an axial velocity component having the opposite direction and the same magnitude in the annular projection 11 is generated. Since this occurs, that is, the annular projection 11 is pressed from both sides, the main shaft 2 is supported by the air thrust bearing 10 in the thrust direction.

At this time, both end surfaces 11 of the annular protrusion 11 are
Since a and 11b are orthogonal to the main shaft 2, when compressed air is blown to the annular protrusion 11 in the axial direction, a large axial velocity component is efficiently generated, so that the main shaft 2 moves in the axial direction. Since it is supported without rattling, and the compressed air ejected from the shaft end side injection port 12A and the oil bearing side injection port 12B flows in the circumferential direction of the main shaft 2 along the annular grooves 13A and 13B. Since the pressure distribution between both end surfaces 11a and 11b of the annular protrusion 11 and the facing surfaces 3a and 3b of the housing 3 facing the end surfaces 11a and 11b becomes uniform in the circumferential direction, the spindle 2 is The air thrust bearing 10 is supported without tilting.

The compressed air flowing in the circumferential direction of the main shaft 2 along the annular grooves 13A and 13B passes through a slight gap between the housing 3 and the annular projection 11 and moves in the centrifugal direction of the air thrust bearing 10. The compressed air flowing in the center direction and flowing in the centrifugal direction is discharged to the outside of the device through the discharge passage 8, so that the pressure of the air thrust bearing 10 becomes higher than necessary without hindering the bearing function. It will be suppressed.

On the other hand, the compressed air flowing in the central direction passes through the shaft end side outflow passage 6A and the oil bearing side outflow passage 6B to the main shaft 2
The compressed air flowing toward the shaft end 2a of the main shaft 2 and the compressed air flowing toward the shaft end 2a of the main shaft 2 prevents foreign matter from entering the inside of the apparatus, and the compressed air flowing toward the oil bearing 4 is the oil bearing. Since the lubricating oil leaking from 4 is prevented from flowing out of the device, the foreign matter can be surely prevented from entering the device and the lubricating oil leaking from the oil bearing 4 flowing out of the device. The compressed air flowing from the air thrust bearing 10 toward the oil bearing 4 through the oil bearing side outflow passage 6B prevents the lubricating oil from the oil bearing 4 from flowing to the shaft end 2a side of the main shaft 2 and together with this lubricating oil. Since it flows into the compressed air recovery passage 7, the outflow of the lubricating oil to the outside of the device can be prevented more reliably.

Therefore, in the above spindle device 1, since the air thrust bearing 10 has both a bearing function and a sealing function, the sealing structure is extremely simple, and the thrust bearing and labyrinth seal, etc., as in the conventional case, are not provided. The distance from the oil bearing 4 to the shaft end 2a of the main shaft 2 becomes shorter as compared with the case where the seal mechanism is individually provided, and as a result, the manufacturing cost is reduced and the main shaft rigidity is significantly improved.

[Second Embodiment] FIG. 2 shows claims 1 to 3 of the present invention.
7 shows an example of a spindle device according to No. 7.

As shown in FIG. 2, the main spindle device 21 according to this embodiment is different from the main spindle device 1 in the first embodiment in that the shaft end side injection port 12A and the oil bearing side injection port 12B of the housing 3 are different from each other. Also, compressed air supplied from the compressed gas supply source P to both end surfaces 11a and 11b of the annular protrusion 11 by communicating with the compressed gas supply source P via the supply paths 25A and 25B, respectively, in a region close to the main shaft 2. Is provided with an axial end side auxiliary injection port 22A and an oil bearing side auxiliary injection port 22B for blowing the air in the axial direction, and the facing surfaces 3a, 3 of the housing 3 are provided.
b are provided with annular auxiliary grooves 23A and 23B for flowing compressed air ejected from the shaft end side auxiliary injection port 22A and the oil bearing side auxiliary injection port 22B in the circumferential direction, respectively, to configure the air thrust bearing 20, and The pressure of the compressed air ejected from the side auxiliary injection port 22A and the oil bearing side auxiliary injection port 22B is set lower than the pressure of the compressed air ejected from the shaft end side injection port 12A and the oil bearing side injection port 12B. Other configurations are the same as those of the spindle device 1 in the first embodiment.

In the spindle device 21, the compressed gas supply source P
From the compressed air supplied through the supply paths 5A and 5B from
From the shaft end side injection port 12A and the oil bearing side injection port 12B of the air thrust bearing 20 to both end faces 11a of the annular projection 11,
11b is blown in the axial direction and flows in the circumferential direction of the spindle 2 along the annular grooves 13A and 13B,
The main shaft 2 is supported by the air thrust bearing 20 in the thrust direction.

During this time, the compressed air having a pressure lower than that of the compressed air is supplied from the shaft end side auxiliary injection port 22A and the oil bearing side auxiliary injection port 22B to both end faces 11a, 11 of the annular projection 11.
When it is blown in the axial direction with respect to b and flows in the circumferential direction of the spindle 2 along the annular auxiliary grooves 23A and 23B,
Axial end side auxiliary injection port 22A and oil bearing side auxiliary injection port 22
Since B is located closer to the main shaft 2 than the shaft end side injection port 12A and the oil bearing side injection port 12B, the low pressure compressed air causes a slight gap between the housing 3 and the annular protrusion 11. Since it flows toward the center of the air thrust bearing 20 and flows toward the shaft end 2a of the main shaft 2 and the oil bearing 4 through the shaft end side outflow passage 6A and the oil bearing side outflow passage 6B, foreign matter can enter the inside of the device. The invasion and the outflow of the lubricating oil leaking from the oil bearing 4 to the outside of the device are reliably prevented.

That is, in this spindle device 21, the air thrust bearing 20 is the same as in the spindle device 1 in the first embodiment.
Has a bearing function as well as a sealing function, which leads to a reduction in manufacturing cost and a dramatic improvement in spindle rigidity, and as described above, the shaft end side injection port 12A and the oil bearing side injection Since the compressed air ejected from the port 12B is used for the bearing and the compressed gas ejected from the shaft end side auxiliary injection port 22A and the oil bearing side auxiliary injection port 22B is used for the sealing, both the thrust bearing function and the sealing function are efficient. Will be good.

[Third Embodiment] FIG. 3 shows claims 1 to 3 of the present invention.
8 shows an example of a spindle device according to No. 8.

As shown in FIG. 3, in the spindle device 31 according to this embodiment, the diameter of each of the shaft end side auxiliary injection port 32A and the oil bearing side auxiliary injection port 32B constituting the air thrust bearing 30 is set to the shaft end side. The pressure of compressed air ejected from the shaft end side auxiliary injection port 32A and the oil bearing side auxiliary injection port 32B is made smaller than the respective diameters of the injection port 12A and the oil bearing side injection port 12B. The pressure is set lower than the pressure of the compressed air ejected from the oil bearing side injection port 12B, and the other configurations are the same as those of the spindle device 21 in the second embodiment.

In other words, in the main spindle device 31, like the main spindle device 21 in the second embodiment, foreign matter enters the interior of the device and leaks from the oil bearing 4 without causing an increase in manufacturing cost and a decrease in rigidity of the main spindle 2. It is possible to reliably prevent the lubricating oil from flowing out of the device, and it is possible to reduce the pressure of the compressed air ejected from the shaft end side auxiliary injection port 32A and the oil bearing side auxiliary injection port 32B with a simple structure. .

[Fourth Embodiment] FIG. 4 shows claims 1 to 3 of the present invention.
7 shows an example of a spindle device relating to Nos. 7 and 9, and FIG.
As shown in FIG. 5, in this spindle device 41, the space volume S2 between the annular auxiliary grooves 23A and 23B forming the air thrust bearing 40 and the annular protrusion 11 is set to the annular grooves 13A and 13B.
The pressure of compressed air ejected from the shaft end side auxiliary injection port 22A and the oil bearing side auxiliary injection port 22B is made wider than the space volume S1 between the shaft end side injection port 12 and the annular projection 11.
The pressure is lower than the pressure of the compressed air ejected from A and the oil bearing side injection port 12B, and the other configurations are the same as those of the spindle device 21 according to the second embodiment.

Therefore, in this spindle device 41, the second
Similar to the spindle device 21 in the embodiment, foreign matter is prevented from entering the device and the lubricating oil leaking from the oil bearing 4 is prevented from flowing out of the device, and the manufacturing cost is reduced and the rigidity of the spindle is significantly improved. In addition, the space volume S2 between the annular auxiliary grooves 23A, 23B and the annular protrusion 11 is shown.
Is larger than the space volume S1 between the annular grooves 13A, 13B and the annular protrusion 11, the flow rate of the compressed air is increased and the sealing function is further improved.

[Fifth Embodiment] FIG. 5 shows claims 1 to 3 of the present invention.
7 shows an example of a main spindle device relating to Nos. 7 and 10, and as shown in FIG. 5, the main spindle device 51 differs from the main spindle device 21 in the second embodiment in that the air thrust bearing 5
The annular discharge grooves 9A and 9B, which are located between the annular grooves 13A and 13B and the annular auxiliary grooves 23A and 23B and communicate with the outside of the housing 3, are provided on the facing surfaces 3a and 3b of the housing 3 which form 0. Other configurations are in the second
It is the same as the spindle device 21 according to the embodiment.

In this spindle device 51, as in the case of the spindle device 21 in the second embodiment, foreign matter invades the inside of the device and leaks from the oil bearing 4 without increasing the manufacturing cost and decreasing the rigidity of the spindle 2. The lubricating oil is reliably prevented from flowing out of the device, and in addition, the pressure on the annular grooves 13A, 13B side partitioned by the annular discharge grooves 9A, 9B and the pressure on the annular auxiliary grooves 23A, 23B side affect each other. Since they do not match, both the thrust bearing function and the seal function are significantly improved.

The detailed construction of the spindle device according to the present invention is as follows.
The present invention is not limited to the above-mentioned first to fifth embodiments,
As another configuration, for example, the annular protrusion 1 as a pressure receiving portion
The end surface of No. 1 (the shaft end side pressure receiving surface and the bearing side pressure receiving surface) may be a tapered surface.

[Brief description of drawings]

FIGS. 1A and 1B are an explanatory sectional view showing a first embodiment of a spindle device according to the present invention and an explanatory sectional view taken along a line AA in FIG. 1A.

FIG. 2 is an explanatory sectional view showing a second embodiment of the spindle device according to the present invention.

FIG. 3 is an explanatory sectional view showing a third embodiment of the spindle device according to the present invention.

FIG. 4 is an explanatory sectional view showing a fourth embodiment of a spindle device according to the present invention.

FIG. 5 is an explanatory sectional view showing a fifth embodiment of the spindle device according to the present invention.

FIG. 6 is a cross-sectional explanatory view showing a conventional spindle device.

[Explanation of symbols]

1, 21, 31, 41, 51, spindle device 2 spindle 2a shaft end 3 housing 3a, 3b facing surface 4 oil bearing (sliding bearing) 6A shaft end side outflow passage 6B oil bearing side outflow passage (sliding bearing side outflow passage) 7 Compressed Gas Recovery Channel 8 Discharge Channel 9A, 9B Annular Discharge Groove 10, 20, 30, 40, 50 Air Thrust Bearing (Gas Thrust Bearing) 11 Annular Protrusion 11a End Face (Shaft End Pressure Receiving Surface) 11b End Face (Bearing Side Pressure Receiving) Surface) 12A Shaft end side injection port 12B Oil bearing side injection port (Sliding bearing side injection port) 13A, 13B Annular groove 22A Shaft end side auxiliary injection port 22B Oil bearing side auxiliary injection port (Slide bearing side auxiliary injection port) 23A, 23B annular auxiliary groove P compressed gas supply source S1, S2 space volume

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yu Owada Nissan Motor Co., Ltd. (2) 2 Takaracho, Kanagawa-ku, Yokohama, Nissan Motor Co., Ltd. (72) Toshikazu Otani 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor (72) Inventor Katsutoshi Miyahara, 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside Nissan Motor Co., Ltd. (72) Inventor Minoru Ota 2 Takara-cho, Kanagawa-ku, Yokohama City, Kanagawa Prefecture Nissan Motor Co., Ltd. (72) Invention Person Manabu Wakuda Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa

Claims (10)

[Claims] 1. A main shaft device comprising a main shaft, a housing for accommodating the main shaft, and a slide bearing provided in the housing for supporting the main shaft in a radial direction in a non-contact state. A gas thrust bearing that supports the main shaft in the thrust direction in a non-contact state with compressed gas is provided at a position closer to the shaft end than the position where
A spindle device, wherein compressed gas is caused to flow from the gas thrust bearing to a shaft end of the spindle and the slide bearing through a space between the spindle and a housing. 2. A main shaft device comprising a main shaft, a housing for accommodating the main shaft, and a slide bearing provided in the housing for supporting the main shaft in a radial direction in a non-contact state. In a portion closer to the shaft end than the portion to be provided, a pressure receiving portion having a shaft end side pressure receiving surface facing the shaft end side of the main shaft and a bearing side pressure receiving surface facing the slide bearing side is provided concentrically with the main shaft, and The housing is provided with a shaft end side injection port and a sliding bearing side injection port for blowing the compressed gas supplied from the compressed gas supply source in the axial direction with respect to the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the pressure receiving portion, A gas thrust bearing that supports the main shaft in a thrust direction in a non-contact state with compressed gas is formed, and between the main shaft and the housing, the gas thrust bearing is connected to the shaft end of the main shaft and the main shaft. A spindle device, characterized in that a shaft end side outflow passage and a slide bearing side outflow passage for respectively flowing out compressed gas toward a slide bearing are provided. 3. The spindle device according to claim 2, wherein the slide bearing side outflow passage is communicated with a compressed gas recovery passage provided in the housing. 4. A discharge passage for discharging compressed gas from the gas thrust bearing to the outside in the housing.
Spindle device described in. 5. The pressure receiving portion is an annular protrusion formed concentrically with the main shaft, and the shaft end side pressure receiving surface and the bearing side pressure receiving surface are both end surfaces of the protrusion orthogonal to the main shaft. The spindle device according to any one of 2 to 4. 6. An annular shape in which compressed gas ejected from a shaft end side injection port and a sliding bearing side injection port flows in a circumferential direction of a main shaft on a surface of the housing facing the shaft end side pressure reception surface and the bearing side pressure reception surface. The spindle device according to any one of claims 2 to 5, wherein each groove is provided. 7. A compressed gas supply source is supplied to the shaft end side pressure receiving surface and the bearing side pressure receiving surface of the pressure receiving portion at a position closer to the main shaft than the shaft end side injection port and the sliding bearing side injection port of the housing. A shaft end side auxiliary injection port that blows compressed gas in the axial direction and a slide bearing side auxiliary injection port are provided, and the pressure of the compressed gas ejected from the shaft end side auxiliary injection port and the slide bearing side auxiliary injection port is injected into the shaft end side injection. The spindle device according to any one of claims 2 to 6, wherein the pressure of the compressed gas ejected from the mouth and the slide bearing side injection port is lower than the pressure of the compressed gas. 8. The shaft end side auxiliary injection is made smaller than the shaft end side injection port and the slide bearing side injection port, respectively. The main spindle device according to claim 7, wherein the pressure of the compressed gas ejected from the mouth and the auxiliary bearing side auxiliary injection port is made lower than the pressure of the compressed gas ejected from the shaft end side injection port and the sliding bearing side injection port. 9. An annular shape in which a compressed gas ejected from a shaft end side auxiliary injection port and a sliding bearing side auxiliary injection port flows in a circumferential direction on a surface of the housing facing the shaft end side pressure receiving surface and the bearing side pressure receiving surface. Auxiliary grooves are respectively provided, and the space volume between the annular auxiliary groove and the pressure receiving portion is adjusted so that the compressed gas ejected from the shaft end side injection port and the slide bearing side injection port flows in the circumferential direction of the main shaft and the pressure receiving part. A space larger than the space between the shaft end side auxiliary injection port and the sliding bearing side injection port to compress the pressure of the compressed gas injected from the shaft end side auxiliary injection port and the sliding bearing side injection port. The spindle device according to claim 7, wherein the pressure is lower than the pressure of the gas. 10. An annular shape, which is located between an annular groove and an annular auxiliary groove, on an opposing surface of the housing facing the shaft end side pressure receiving surface and the bearing side pressure receiving surface, and which discharges compressed gas to the outside of the gas thrust bearing. The spindle device according to claim 9, wherein a discharge groove is provided.