JPH09295238A - Air spindle - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an air spindle having a simple structure and high cooling efficiency. An air spindle 1 has a rotor 2 and a housing 6. Rotor 2 is turbine 3
And a hollow rotating shaft 4, a connecting member 51, and a tool 5. The housing 6 includes a housing body 7 that defines a turbine chamber 71, and a support member 8 that rotatably supports the rotating shaft 4 via a static pressure pad 9. An air supply port 72 and an air discharge port 73 communicating with the turbine chamber 71 are formed in the housing body 7. The hollow portion 41 of the rotary shaft 4 has a base end that is the turbine 3
Is communicated with the turbine chamber 71 through a through hole 32 formed in the inner wall of the connecting member 51 and the tool 52.
It is open to the atmosphere through the through hole 53 formed in the.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air spindle having a cooling function.

[0002]

2. Description of the Related Art There is known an air spindle having a structure in which a turbine is rotated by injecting pressurized air to thereby rotate a rotor and a cutting tool installed at an end of the rotor.

The structure of this conventional air spindle is shown in FIG.
Shown in As shown in the figure, the conventional air spindle 1
00 is the turbine 10 housed in the turbine chamber 101.
3 and a rotating shaft 10 whose one end is connected to the turbine 103
4 and a tool (cutting / cutting) connected to the other end of the rotary shaft 104.
Grinding tool) 105 and a housing 106 that houses the turbine 103 and the rotating shaft 104 of the rotor 102.
The compressed air (compressed air) supplied from the air supply port 107 formed at 6 collides with the blades of the turbine 103 at high speed to rotationally drive the turbine 103 and thereby rotate the rotor 102.

In this case, a static pressure pad 109 is installed on the outer circumference of the rotary shaft 104, and air is supplied to a slight gap between the rotary shaft 104 and the static pressure pad 109 to form a thin air layer 110. The air layer 110 acts as an air bearing.

In such an air spindle 100,
Due to the high speed rotation of the rotor 102, frictional heat (air shearing insulation) is generated between the rotating shaft 104 and the static pressure pad 109. When the temperature of the rotary shaft 104 rises due to this frictional heat, the rotary shaft 104 expands, the machining position of the tool 105 shifts, and the machining accuracy decreases. In some cases, thermal expansion of the rotary shaft 104 causes the rotor 102 to rotate. May be disturbed. Therefore, a mechanism for cooling the rotating shaft 104 is provided.

This rotary shaft cooling mechanism is mainly an outer cylinder (air jacket) installed so as to surround the entire circumference of the outer peripheral portion of the static pressure pad 109 and the supporting member 108 supporting it.
Air is supplied from the cooling air supply port 112 formed in the outer cylinder 111 into the outer cylinder to cool the support member 108 and the like, and then the cooling air exhaust formed in the outer cylinder 111 as well. It is configured to discharge from the outlet 113.

However, such a rotating shaft cooling mechanism has the following drawbacks. First of all, turbine 1
It is necessary to install an air supply system for cooling the rotating shaft separately from the air supply system for rotating 03, which leads to a complicated structure and an increase in size of the apparatus.

Secondly, this rotary shaft cooling mechanism is provided with the rotary shaft 1
04 is cooled from the outside, but the rotating shaft 10
Instead of directly contacting 4 with cooling air,
Since cooling is performed via the support member 108 and the static pressure pad 109, the cooling efficiency is low.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an air spindle having a simple structure and high cooling efficiency.

[0010]

This and other objects are achieved by the present invention which is defined below as (1) to (7).

(1) A rotor having a turbine and a rotating shaft connected to the turbine, and a turbine chamber for accommodating the turbine are defined, and an air supply port and an air discharge port communicating with the turbine chamber are formed. An air spindle for rotating the rotor by rotating the turbine by the air supplied to the turbine chamber from the air supply port, and utilizing a part of the air for rotating the turbine. An air spindle comprising a cooling mechanism for cooling the rotating shaft.

(2) A rotor having a turbine and a hollow rotating shaft connected to the turbine, a turbine chamber for accommodating the turbine, and an air supply port and an air discharge port communicating with the turbine chamber are defined. An air spindle that has a formed housing, rotates the turbine by the air supplied to the turbine chamber from the air supply port, and rotates the rotor. An air spindle comprising a cooling mechanism configured to supply the hollow portion of the rotating shaft to cool the rotating shaft from the inside.

(3) The air spindle according to the above (2), wherein an air inflow side of a hollow portion of the rotating shaft communicates with the turbine chamber.

(4) The air spindle according to (2) or (3), wherein the air outflow side of the hollow portion of the rotating shaft is open to the atmosphere.

(5) The air inflow side of the hollow portion of the rotating shaft communicates with the turbine chamber, and the air outflow side of the hollow portion of the rotating shaft is open to the atmosphere, and the pressure between the turbine chamber and the atmosphere is increased. The air spindle according to (2) above, wherein air flows through the hollow portion due to a difference.

(6) The air spindle according to any one of (2) to (5), wherein the hollow portion of the rotary shaft has a portion whose inner diameter changes continuously or stepwise along the axial direction.

(7) The air spindle according to any one of the above (1) to (6), wherein a tool is installed at an end of the rotor opposite to the turbine.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the air spindle of the present invention shown in the accompanying drawings will be described in detail below.

FIG. 1 shows a first air spindle according to the present invention.
It is a longitudinal section showing an example. Note that the upper side in FIG. 1 will be described as a “base end” and the lower side will be described as a “distal end”.

As shown in FIG. 1, the air spindle 1 of the present invention includes a rotor 2, a housing 6, and a rotor 2.
And a cooling mechanism for cooling at least the rotating shaft 4. Hereinafter, these configurations will be described in detail.

The rotor 2 has a plurality of blades on its outer periphery.
A turbine 3 in which 31 is radially formed, a hollow rotary shaft 4 connected to the tip side of the turbine 3, and a tool (accessory) 5 connected to the tip side of the rotary shaft 4 via a connecting member 51 It consists of and.

A through hole 32 is formed in the center of the turbine 3 so as to penetrate from the tip to the base of the turbine 3.
The through hole 32 communicates with the hollow portion 41 of the rotary shaft 4. Therefore, the base end (air inflow side) of the hollow portion 41 of the rotating shaft 4 is provided with the turbine chamber 71, which will be described later, via the through hole 32.
Is in communication with.

The connecting member 51 has a ring shape,
Further, at the center of the tool 5, a through hole 53 that penetrates from the tip to the base end of the tool 5 is formed. Therefore, the distal end (air outflow side) of the hollow portion 41 has the inner cavity 52 of the connecting member 51.
And to the atmosphere via the through hole 53.

The through hole 32, the hollow portion 41, the inner cavity 52 and the through hole 53 as described above constitute an air flow path (cooling mechanism) for cooling the rotating shaft 4.

As shown in FIG. 1, the hollow portion 41 of the rotary shaft 4
Has its inner diameter continuously or stepwise changed along the axial direction. That is, it has at least one step portion 42. As a result, the contact area (cooling area) with the cooling air flowing through the hollow portion 41 increases, and the flow of air (particularly the flow state and flow velocity) changes, resulting in higher cooling efficiency.

The tool 5 is a tool for cutting, grinding, and polishing, and its tip has a cutting tool for cutting, a grindstone for cutting, and polishing. A polishing pad is mounted, and in this embodiment, a grindstone 54 is mounted.

The housing 6 is composed of a housing body 7 and a tubular support member 8 connected to the tip side of the housing body 7.

The housing body 7 defines a turbine chamber 71 in which the turbine 7 is housed, and an air supply port 72 communicating with the turbine chamber 71 is formed in the outer peripheral portion on the tip end side. The base end of the housing body 7 has a tapered tubular shape whose outer diameter and inner diameter gradually decrease, and an air discharge port 73 communicating with the turbine chamber 71 is formed at the base end (top) of this portion. ing.

The air supply port 72 is bent toward the base end of the housing body 7 in the middle of the air supply port 72 and faces the blades (blades) 31 of the turbine 3. To the air supply port 72, a tube (not shown) for transferring the pressurized air from the air supply source is connected.

The support member 8 is a member that rotatably supports the rotary shaft 4 of the rotor 2 via a static pressure pad 9. A tubular static pressure pad 9 is fixedly supported inside the support member 8, and the rotary shaft 4 is inserted inside the static pressure pad 9.

In this case, a slight gap is formed between the outer peripheral surface of the rotary shaft 4 and the inner peripheral surface of the static pressure pad 9, and a pipe formed through the support member 8 and the static pressure pad 9. 81
By supplying more air, a thin air layer 91 is formed in this gap. This air layer 91 acts as an air bearing, and smooth rotation of the rotary shaft 4 is ensured. The air supplied between the outer peripheral surface of the rotary shaft 4 and the inner peripheral surface of the static pressure pad 9 is exhausted from an exhaust port 82 formed in the support member 8.

Next, the operation of the air spindle 1 will be described. When pressurized air (compressed air) is supplied from the air supply port 72 as indicated by an arrow indicating the flow of air in FIG. 1, this air collides with the blades 31 of the turbine 3 to rotate the turbine 3, As a result, the rotor 2 rotates at high speed, for example, 10,000 to 20,000 rpm. And
By rotating the grindstone 54 installed at the tip of the rotor 2, a predetermined work piece is cut, ground or polished.

The air that has collided with the blades 31 of the turbine 3 is
After being introduced into the turbine chamber 71, it is discharged from the air discharge port 73.

On the other hand, air is supplied to the gap between the outer peripheral surface of the rotary shaft 4 and the inner peripheral surface of the static pressure pad 9 through the pipe 81, and a thin air layer 91 is formed in this gap. The air layer 91 acts as an air bearing, and the rotary shaft 4 rotates smoothly. Friction heat (shear insulation) of the air layer 91 is generated in the gap due to the high speed rotation of the rotating shaft 4, and the temperature of the rotating shaft 4 rises. Therefore, the rotating shaft 4 is cooled as described later.

In the turbine chamber 71, the pressure of the air supplied from the air supply port 72 exceeds the atmospheric pressure (for example, about 2 to 6 atmospheric pressure). Due to the pressure difference between the pressure in the turbine chamber 71 and the atmospheric pressure, the turbine chamber 7
As shown by the arrow in FIG. 1, a part of the air introduced into the turbine 1 flows into the through hole 32 formed in the central portion of the turbine 3, and further the hollow portion 41 of the rotary shaft 4 is moved in the distal direction. Flow toward and then pass through lumen 52 and through hole 53 and are released to the atmosphere.

Due to such air circulation, the rotating shaft 4
Are cooled directly from the inside. As described above, since the rotary shaft 4 is directly cooled, and further, the rotary shaft 4 has a hollow tubular shape and has a thin wall portion having a low heat capacity, the conventional air spindle 100 shown in FIG. compared,
High cooling efficiency. In particular, in the turbine chamber 71, adiabatic expansion occurs and the temperature of the air is lowered (for example, about 5 to 10 ° C. lower than the atmosphere), so the air flowing through the hollow portion 41 is also at a low temperature, and An extremely high cooling effect can be obtained.

Further, in the air spindle 1, unlike the conventional air spindle 100, it is not necessary to separately provide an air supply system for cooling the rotary shaft 4 in addition to the air supply system for rotationally driving the turbine 3. Therefore, the configuration is simple and the device can be downsized.

FIG. 2 shows a second air spindle according to the present invention.
It is a longitudinal section showing an example. Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment.
Note that the upper side in FIG. 2 will be described as a “base end” and the lower side will be described as a “tip”.

The air spindle 10 shown in FIG. 2 has a rotor 12, a housing 16, and a cooling mechanism for cooling at least the rotating shaft 4 of the rotor 12.

The turbine 3, the rotating shaft 4, the connecting member 51, and the tool (accessory) 5 that form the rotor 12 are solid, that is, the through hole 32 and the hollow portion 4.
1, except that the inner cavity 52 and the through hole 53 are not provided.

In the housing body 7 which constitutes the housing 16, a branch path 75 branched from the middle of the air supply port 72 is provided.
Are formed. The branch path 75 communicates with a cooling chamber 18 described later.

An outer cylinder (air jacket) 17 is formed on the outer periphery of the support member 8 as a cooling mechanism so as to surround the entire outer periphery of the support member 8. This outer cylinder 17
A cooling chamber 18 is formed between the support member 8 and the inside of the cooling chamber 18. Further, the outer cylinder 17 is formed with a cooling air discharge port 19 communicating with the cooling chamber 18.

Next, the operation of the air spindle 10 will be described. As described above, when pressurized air (compressed air) is supplied from the air supply port 72 while forming the air bearing, this air collides with the blades 31 of the turbine 3 to rotate the turbine 3 and, as described above, Then, the rotor 12 is rotated at a high speed, and the rotor 12 is further discharged from the air discharge port 73 through the turbine chamber 71.

On the other hand, a part of the compressed air (compressed air) supplied from the air supply port 72 is supplied to the cooling chamber 18 via the branch passage 75 as shown by the arrow in FIG.
While flowing through 8, the rotating shaft 4 is cooled from the outside through the support member 8 and the static pressure pad 9. The air used for cooling is discharged from the cooling air discharge port 19.

In the air spindle 10, unlike the conventional air spindle 100, it is not necessary to separately provide an air supply system for cooling the rotary shaft 4 in addition to the air supply system for rotationally driving the turbine 3. Therefore, the configuration is simple and the device can be downsized.

The air spindle of the present invention has been described above based on the illustrated embodiments, but the present invention is not limited to these, and each component of the present invention has a similar function. It can be replaced with other configurations that occur.

[0047]

As described above, according to the air spindle of the present invention, it is not necessary to separately provide an air supply system for cooling, so that the structure is simple and it contributes to downsizing of the apparatus. .

Further, according to the air spindle of the present invention, the cooling efficiency is high and, therefore, due to the thermal expansion of the rotary shaft,
It is possible to effectively prevent adverse effects such as deviation of the processing position and obstruction of rotation of the rotor.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of an air spindle of the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the air spindle of the present invention.

FIG. 3 is a vertical sectional view showing the structure of a conventional air spindle.

[Explanation of symbols]

 1 Air Spindle 2 Rotor 20 Central Axis 3 Turbine 31 Blade 32 Through Hole 4 Rotating Axis 41 Hollow 42 Step 5 Tool 51 Connecting Member 52 Inner Lumen 53 Through Hole 54 Grinding Stone 6 Housing 7 Housing Main Body 71 Turbine Chamber 72 Air Supply Port 73 Air discharge port 75 Branch path 8 Support member 81 Pipe 82 Exhaust port 9 Static pressure pad 91 Air layer 10 Air spindle 12 Rotor 16 Housing 17 Outer cylinder 18 Cooling chamber 19 Cooling air discharge port 100 Air spindle 101 Turbine chamber 102 Rotor 103 Turbine 104 rotary shaft 105 tool 106 housing 107 air supply port 108 support member 109 static pressure pad 110 air layer 111 outer cylinder 112 cooling air supply port 113 cooling air discharge port

Claims (7)

[Claims] 1. A rotor having a turbine and a rotating shaft connected to the turbine, and a turbine chamber for accommodating the turbine are defined, and an air supply port and an air discharge port communicating with the turbine chamber are formed. An air spindle that has a housing, rotates the turbine by the air supplied to the turbine chamber from the air supply port, and rotates the rotor, utilizing a part of the air for rotating the turbine. An air spindle comprising a cooling mechanism for cooling the rotating shaft. 2. A rotor having a turbine and a hollow rotating shaft connected to the turbine, and a turbine chamber for accommodating the turbine are defined, and an air supply port and an air discharge port communicating with the turbine chamber are formed. An air spindle for rotating the rotor by rotating the turbine by the air supplied to the turbine chamber from the air supply port, wherein a part of the air for rotating the turbine is An air spindle, comprising a cooling mechanism configured to supply the hollow portion of the rotary shaft to cool the rotary shaft from the inside thereof. 3. The air spindle according to claim 2, wherein an air inflow side of the hollow portion of the rotary shaft is communicated with the turbine chamber. 4. The air spindle according to claim 2, wherein the air outlet side of the hollow portion of the rotary shaft is open to the atmosphere. 5. An air inflow side of the hollow portion of the rotating shaft communicates with the turbine chamber, and an air outflow side of the hollow portion of the rotating shaft is open to the atmosphere, and a pressure difference between the turbine chamber and the atmosphere is formed. The air spindle according to claim 2, wherein air circulates in the hollow portion by means of. 6. The air spindle according to claim 2, wherein the hollow portion of the rotary shaft has a portion whose inner diameter changes continuously or stepwise along the axial direction. 7. The air spindle according to claim 1, wherein a tool is installed at an end of the rotor opposite to the turbine.