Rotating device

Abstract

To provide a rotating device that can seal fluid for cooling a spindle coping with a high speed more surely to prevent the fluid from entering a region of a motor.SOLUTION: A rotating device, which comprises an enclosure, a hollow spindle rotatably provided in the enclosure and a rotary joint provided in the spindle, comprises cooling means for cooling the spindle, where the rotary joint is constituted of a rotary shaft and a fixed sleeve. The cooling means is configured to be able to cool the boundary part between the rotary shaft and the spindle. The rotary shaft is fixed to be rotatable together with the spindle, and seal members are provided on both sides in an axial direction, between the outer peripheral surface of the rotary shaft and the inner peripheral surface of the spindle.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a rotating device.

Background Art

[0002] Conventionally, various techniques for cooling a table rotating shaft that generates a large amount of heat have been disclosed. Patent Document 1 discloses a rotating electric machine having a hollow rotating shaft rotatably supported by a bearing, a fixed shaft inserted inside the rotating shaft, and a first refrigerant flow path formed between the rotating shaft and the fixed shaft. Further, Patent Document 2 discloses a rotary table device having a first passage provided in a shaft portion, one end of which communicates with a shaft gap G1 between the shaft portion and a table main shaft via a cooling passage and a sleeve gap G2, and the other end of which communicates with the outside of the device body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, rotary contact seals 14 are provided on both axial sides between a rotating shaft 7 and a fixed shaft 8, and the refrigerant flowing through the first refrigerant flow path 9 is sealed by these rotary contact seals 14. Further, in Patent Document 2, an annular sealing material 23f is interposed between the outer peripheral surface of the rear end portion of the table spindle 12 and the inner peripheral surface of the frame rear end member 23, thereby sealing the shaft gap G1. That is, in both Patent Documents 1 and 2, a seal is provided between a rotating body and a non-rotating body, and this seal enables the refrigerant flowing through the path to be sealed. However, the seal may wear due to rotation. Also, there is a risk that the refrigerant may enter the motor region due to wear and damage the motor.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a rotating device capable of more reliably sealing a fluid so that the fluid for cooling the spindle corresponding to high speed does not enter the motor region.

Means for Solving the Problems

[0006] The disclosed technology relates to a rotating device. The rotating device includes a housing, a hollow spindle rotatably provided within the housing, and a rotary joint provided within the spindle. The rotary joint is composed of a rotating shaft and a fixed sleeve. In the rotating device, a cooling means for cooling the spindle is provided. The cooling means is configured to be able to cool the boundary portion between the rotating shaft and the spindle. The rotating shaft is fixedly provided so as to be rotatable integrally with the spindle. A sealing material is provided on both axial sides between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the spindle.

[0007] Preferably, the cooling means includes a groove portion communicating with a supply path and a recovery path within the rotary joint, and the groove portion is provided within the sealing material. Rotating device.

[0008] Preferably, the groove portion extends along the axial direction, at least two or more are formed in the circumferential direction, and each is a groove communicating with each other. Rotating device.

[0009] Preferably, the groove portion is a circular groove formed continuously in the circumferential direction, the rotating device.

[0010] Preferably, the groove portion is a groove provided in a spiral shape, the rotating device.

[0011] Preferably, the rotating shaft has the other end extending rearward from the housing, and a fixing sleeve is fitted to the other end, the rotating device.

[0012] Preferably, the other end is composed of a separate member, the rotating device.

[0013] Preferably, the rotating shaft has a flange portion protruding from the outer peripheral surface, and is fixed to the spindle via the flange portion, the rotating device.

[0014] According to the disclosed technology, the fluid can be more reliably sealed so that the fluid for cooling the spindle corresponding to the high speed does not enter the motor region.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the disclosed technology will be described. However, the following description is merely illustrative in nature.

[0017] Unless otherwise specified, the "axial direction" used in the description means the direction in which the rotation axis J extends. Similarly, the "circumferential direction" means the direction of the circumference centered on the rotation axis J, and the "radial direction" means the direction of the radius or diameter centered on the rotation axis J. "Front" means the side used during processing, and "rear" means the side not used during processing.

[0018] 1. NC Circular Table FIG. 1 and FIG. 2 show an NC circular table 1 (an example of a rotating device) to which the disclosed technology is applied. Hereinafter, the NC circular table 1 will be described with reference to FIGS. 1 and 2. The NC circular table 1 mainly includes a housing 2, a box 3, a spindle 4, a motor 5, a rotary joint 6, etc. The NC circular table 1 is used for machining, and the table body 42 on its front surface rotates at high speed.

[0019] That is, a chuck (an example of a jig) is attached to the table body 42 to support a workpiece (object to be processed). In such a state, the spindle 4 is rotationally driven at high speed. Then, while supplying cooling oil or cutting fluid to the rotating workpiece, machining is performed with a cutting tool or the like.

[0020] <Housing> The housing 2 is composed of a main body portion 21, a front cover portion 22, a rear cover portion 23, etc. A cylindrical accommodation space 21a penetrating in the front-rear direction is formed in the main body portion 21.

[0021] (Rear Cover Portion) The rear cover portion 23 is made of a disk-shaped member. The rear cover portion 23 is fitted into a circular recess formed on the rear side of the main body portion 21. The rear cover portion 23 is assembled to the rear side of the main body portion 21 so as to cover the rear side of the accommodation space 21a. A circular opening 23a is formed in the rear cover portion 23. The center line of the opening 23a and the rotation axis J substantially coincide.

[0022] (Front cover part) The front cover part 22 is made of a disc-shaped member. The front cover part 22 is fitted into a circular recess formed on the front side of the main body part 21. The front cover part 22 is assembled to the front side of the main body part 21 so as to cover the front side of the accommodation space 21a. A circular opening 22a is formed in the front cover part 22. The center line of the opening 22a and the rotation axis J substantially coincide. An annular bearing 7 is arranged on the front side of the accommodation space 21a.

[0023] <Bearing> The bearing 7 is annular and is arranged on the front side of the accommodation space 21a. The bearing 7 has an outer ring part 7a and an inner ring part 7b that rotate freely with respect to each other. The bearing 7 is assembled to the housing 2 by sandwiching its outer ring part 7a between the main body part 21 and the front cover part 22.

[0024] <Box> The box 3 is made of a box-shaped container and is assembled to one side surface of the housing 2. Inside the box 3, various cables used for driving and controlling the NC circular table 1, and electrical devices such as solenoid valves and pressure sensors are arranged. Electric power is supplied to the NC circular table 1 through a cable (not shown) led out from the box 3.

[0025] <Spindle> The spindle 4 has a shaft 41 and a table body 42.

[0026] (Shaft) The shaft 41 is made of a multi-stage cylindrical member and is accommodated in the accommodation space 21a. A circular opening 41a is formed in the shaft 41. The center line of the opening 41a and the rotation axis J substantially coincide.

[0027] (Table body) The table body 42 is a disc-shaped member having an outer diameter slightly smaller than the inner diameter of the opening 22a, and is assembled to the front end face of the shaft 41. A circular opening 42a is formed in the table body 42. The center line of the opening 42a and the rotation axis J substantially coincide with each other.

[0028] By assembling the shaft 41 and the table body 42, the inner ring portion 7b of the bearing 7 is sandwiched between the shaft 41 and the table body 42. Thereby, the spindle 4 is pivotally supported by the housing 2 via the bearing 7 and is rotatable about the rotation axis J. In other words, the spindle 4 constitutes a rotating body. Note that the spindle 4 may be configured by combining a plurality of parts or may be integrally configured.

[0029] As described above, the table body 42 is a portion of the spindle 4 where the workpiece is gripped via a chuck (an example of a jig), and the front surface of the table body 42 is exposed to the front surface of the housing 2 through the opening 22a.

[0030] <Motor> The motor 5 has a rotor 51 and a stator 52 and is accommodated in the accommodation space 21a. The rotor 51 is an annular member and is fixed to the spindle 4. The stator 52 is an annular member larger than the rotor 51 and is fixed to the main body portion 21 in a state of being opposed to the rotor 51 in the radial direction with a slight gap therebetween.

[0031] By supplying a predetermined control current to the stator 52, a rotating magnetic field is formed between the stator 52 and the rotor 51. Thereby, the spindle 4 is directly driven and rotates at a predetermined high speed (for example, the peripheral speed at the outer circumference of the rotor 51 is 10 m / s or more) (so-called direct drive type).

[0032] Note that as the rotation speed of the spindle 4 increases, the amount of heat generated by the motor 5 during driving of the motor 5 also increases. Therefore, when proceeding with high-speed rotation, dealing with the heat generation of the motor is also important.

[0033] <Seal structure> In the gap between the table body 42 which is a rotating body and the front cover part 22 which is a non-rotating body, an annular front seal material FS (oil seal) is provided to prevent foreign matters such as chips and cutting water from entering the accommodation chamber 21a through the gap. Similarly, in the gap between the shaft 41 which is a rotating body and the rear cover part 23 which is a non-rotating body, an annular rear seal material BS (oil seal) is provided to prevent foreign matters from entering the accommodation chamber 21a through the gap.

[0034] <Rotary joint> The rotary joint 6 is composed of a rotating shaft 61 and a fixed sleeve 62, and is configured to supply the fluid supplied to the fixed sleeve 62 to the rotating shaft 61. Similarly, it is configured to recover the fluid recovered from the rotating shaft 61 to the fixed sleeve 62. One end side of the rotary joint 6 is provided inside the spindle, and the other end side extends outside the rear cover part 23 (housing 2).

[0035] (Rotating shaft) The rotating shaft 61 is configured to be rotatable together with the shaft 41 (spindle 4). The rotating shaft 61 has a first rotating shaft 61a whose one end side is covered by the spindle 4 and a second rotating shaft 61b whose other end side is covered by the fixed sleeve 62 outside the housing. The first rotating shaft 61a and the second rotating shaft 61b are fixed with bolts so that their axes and the rotation axis J substantially coincide.

[0036] (First rotating shaft) The first rotating shaft 61a is made of a cylindrical member and is accommodated in the opening 41a of the shaft 41. At the rear end of the first rotating shaft 61a, a circular first flange portion 61a that protrudes radially outward from its outer peripheral surface 1 is provided. This first flange portion 61a 1The shaft 41 and the first rotating shaft 61a are fixed to each other with bolts via [the relevant part]. As a result, the spindle 4 and the first rotating shaft 61a are integrated, and the first rotating shaft 61a can follow the rotation of the spindle 4. Note that the first rotating shaft 61a and the shaft 41 are fixed with bolts so that their respective axes and the rotation axis J are substantially coincident.

[0037] (Second Rotating Shaft) The second rotating shaft 61b is composed of a cylindrical member and is covered by a fixed sleeve 62 outside the housing 2. At the front end of the second rotating shaft 61b, a circular second flange portion 61b that protrudes radially outward from its outer peripheral surface 1 is provided. Through this second flange portion 61b 1 the second rotating shaft 61b and the first rotating shaft 61a are fixed to each other with bolts. As a result, the spindle 4, the first rotating shaft 61a, and the second rotating shaft 61b are integrated, and the second rotating shaft 61b can follow the rotation of the spindle 4. Note that the first rotating shaft 61a and the second rotating shaft 61b are fixed with bolts so that their respective axes and the rotation axis J are substantially coincident.

[0038] (Fixed Sleeve) The fixed sleeve 62 is attached to the housing 2 in a non-rotating state outside the housing 2. Specifically, one side of the bracket 8 is attached to the fixed sleeve 62, and the other side of the bracket 8 is attached to the housing 2. Thereby, the fixed sleeve 62 is integrated with the housing 2 via the bracket 8 and is configured not to rotate. Also, the outer peripheral surface of the fixed sleeve 62 is configured to be able to supply fluid to the rotating shaft 61 or recover fluid from the rotating shaft 61.

[0039] <Sealing Material for Fluid> The sealing material S for fluid is a ring-shaped seal capable of sealing fluid, and is provided between the outer peripheral surface of the first rotating shaft 61a and the inner peripheral surface of the shaft 41 (spindle 4), and is provided on both axial sides.

[0040] <Cooling means> The NC circular table 1 in this embodiment is provided with a cooling means for cooling the spindle with a fluid. The cooling means includes a groove portion R communicating with a supply path and a recovery path in the rotary joint 6, and this groove portion R is provided within the sealing materials S, S. Specifically, the groove portion R is provided between the outer peripheral surface of the first rotating shaft 61a and the inner peripheral surface of the shaft 41 (spindle 4) (boundary portion). As shown in FIG. 2, preferably, the groove portion R is a circular groove that extends along the axial direction on the outer peripheral surface of the first rotating shaft 61a and is continuously formed in the circumferential direction. However, it is not limited to this, and it may be a groove that extends along the axial direction and is formed at least two or more times in the circumferential direction, with each being communicated.

[0041] With such a configuration, the fluid supplied from the supply path in the rotary joint 6 enters the groove portion R between the rotating shaft 61 and the spindle 4, and the fluid is recovered from the recovery path in the rotary joint 6 and circulated, thereby cooling the spindle 4 which is a rotating body. Further, since the rotating shaft 61 and the spindle 4 are fixed, the sealing materials S, S do not wear due to rotation, and the inside of the groove R can be maintained in a sealed state.

[0042] <First modification example> FIG. 3 shows a first modification example of the above-described NC circular table 1. The basic configuration of the NC circular table 1A in this modification example is the same as that of the above-described NC circular table 1. Therefore, for the same configuration, the same reference numerals are used and the description thereof is omitted (the same applies to the second and third modification examples described later). In the NC circular table 1A, in particular, the configuration of the groove portion R1 is different from that of the above-described groove portion R. Specifically, the groove portion R1 is a spiral groove formed along the axial direction. Thereby, since the fluid flows along the spiral groove, it becomes easy to uniformly cool the spindle 4.

[0043] <Second modification example> Figure 4 shows a second modification of the above-described NC circular table 1. In the NC circular table 1B of this modification, in particular, the configuration of the rotating shaft 61 is different from that of the above-described NC circular table 1. Specifically, the rotating shaft 61 in the NC circular table 1 combines two members, a first rotating shaft 61a and a second rotating shaft 61b, integrally, whereas the rotating shaft 61 in the NC circular table 1B is integrally formed. As a result, centering of the first rotating shaft 61a and the second rotating shaft 61b becomes unnecessary, and assembly becomes easy.

[0044] <Third Modification> Figure 5 shows a third modification of the above-described NC circular table 1. In the NC circular table 1C of this modification, in particular, the fixing position of the rotating shaft 61 and the spindle 4 is different from that of the above-described NC circular table 1B (Fig. 4). Specifically, it is configured such that the fixing position is performed outside the housing 2. That is, the shaft 41 is extended to the rear of the housing 2, and the first flange portion 61a of the rotating shaft 61 is 1 abutted and fixed to the end face thereof. As a result, when removing the rotating shaft 61 for maintenance or the like, work can be performed while ensuring the sealing performance of the seal BS, so that the maintainability is improved.

[0045] 5. Conclusion As described above, according to the present embodiment, the fluid can be more reliably sealed so that the fluid for cooling the spindle corresponding to the high speed does not enter the motor region. Specifically, the fluid supplied from the supply path in the rotary joint 6 enters the groove portion R between the rotating shaft 61 and the spindle 4, and the fluid is recovered from the recovery path in the rotary joint 6 and circulated, thereby cooling the spindle 4 which is a rotating body. Further, since the rotating shaft 61 and the spindle 4 are fixed, the sealing materials S, S do not wear due to rotation, and the inside of the groove R can be maintained in a sealed state.

[0046] Finally, although the embodiments and modifications according to the present invention have been described, these are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and their modifications are included in the scope and gist of the invention and are also included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0047] 1... NC circular table (rotating device), 2... housing, 3... box, 4... spindle, 5... motor, 6... rotary joint, 7... bearing, 7a... outer ring part, 7b... inner ring part, 21... main body part, 21a... accommodation space, 22... front cover part, 22a... opening, 23... rear cover part, 23a... opening, 41... shaft, 41a... opening, 42... table body, 42a... opening, 51... rotor, 52... stator, 61... rotating shaft, 61a... first rotating shaft, 61a 1 ... first flange part, 61b... second rotating shaft, 61b 1 ... second flange part, 62... fixed sleeve, J... rotation axis, FS... sealing material, BS... sealing material, S... sealing material

Claims

1. A housing, a hollow spindle rotatably provided within the housing, and a rotary joint provided within the spindle, comprising: the rotary joint includes a rotating shaft and a fixed sleeve, in a rotating device composed of, cooling means for cooling the spindle, the cooling means is configured to be able to cool the boundary portion between the rotating shaft and the spindle, the rotating shaft is rotatably fixed integrally with the spindle, a sealing material is provided on both axial sides between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the spindle, Rotating device.

2. The rotating device according to claim 1, wherein the cooling means includes a groove portion communicating with a supply path and a recovery path within the rotary joint, the groove portion is provided within the sealing material, Rotating device.

3. The rotating device according to claim 2, wherein the groove portion extends along the axial direction and is formed in at least two or more in the circumferential direction, and each is a groove communicated with each other, Rotating device.

4. The rotating device according to claim 2, wherein the groove portion is a circular groove formed continuously in the circumferential direction, Rotating device.

5. The rotating device according to claim 2, wherein the groove portion is a groove provided in a spiral shape, Rotating device.

6. The rotating device according to any one of claims 3-5, wherein the other end of the rotating shaft extends rearward from the housing, the fixed sleeve is fitted to the other end, Rotating device.

7. The rotating device according to claim 6, wherein the other end is composed of a separate member, Rotating device.

8. The rotating device according to claim 1, wherein the rotating shaft has a flange portion protruding from the outer peripheral surface, and is fixed to the spindle via the flange portion, Rotating device.

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