JP2004322306A - Main spindle unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive main spindle unit easy in maintenance, and superior in incorporation performance. <P>SOLUTION: This main spindle unit 1 has: an outer cylinder 3 having a stator 4 and a sleeve housing 5; a freely rotatable rotary shaft 6 having a rotor 7; a front side bearing 12 being a combinational angular ball bearing having an outer ring fixed to a front housing 8, and having an inner ring fitted around one end of the rotary shaft 6; a bearing sleeve 11 arranged on the other end side of the rotary shaft 6, and movable in the shaft direction of the rotary shaft 6 by fitting to the sleeve housing 5; and a rear side bearing 13 being a pair of angular ball bearings having an inner ring fitted around the other end of the rotary shaft 6, having an outer ring fixed to the bearing sleeve 11, and rotatably supporting the rotary shaft 6 by cooperating with the front side bearing 12. Further, the unit is constituted so that a semi-assembly 2 composed of the front housing 8, the rotary shaft 6, and the bearing sleeve 11, can be extracted from the outer cylinder 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a spindle device for a machine tool or the like.

  As a conventional spindle device of a machine tool or the like, a built-in motor spindle device as shown in FIG. 13 is known (for example, see Patent Documents 1 and 2).

  The built-in motor spindle device 80 shown in FIG. 13 includes a motor housing 83 held by a unit support member 82, and a front housing 84 connected to the front of the motor housing. A spindle body 85 provided inside the motor housing 83 and the front housing 84 and a stator 86 fixed to the inner periphery of an intermediate portion of the motor housing 83 are provided. A rotor 87 is fixed to the outer periphery of the intermediate portion of the spindle body 85. Have been.

The spindle body 85 has a hollow cylindrical shape. A drawbar 89 urged by a disc spring 88 and slidable in the cylinder is provided in the cylinder, and a chuck portion 89a is provided at the tip of the drawbar 89. I have. Four front bearings 92 are provided between the front housing 84 and the spindle body 85. A rear bearing 93 as a cylindrical roller bearing and a bearing sleeve 94 are externally fitted on the outer periphery of a rear portion of the spindle body 85, and a rear cover 95 is bolted to a rear portion of the motor housing 83.
JP-A-7-112303 (page 2-3, FIG. 1) JP-A-2003-159622 (pages 4 to 5, FIG. 1)

  By the way, in a machine tool, a main shaft failure is often caused by mainly causing damage to a bearing, which is caused by a bearing life, a spindle collision due to a machining program error, and the like. It is important to reduce the time (downtime) from the failure of the spindle to the return of the spindle, particularly at a parts processing site directly connected to a production line such as processing of automobile parts. In addition, the speed of the main spindle of machine tools has been increasing, and the life of the spindle bearing has been virtually unlimited to 100,000 hours or more for low-speed machines (less than 600,000 dmN), whereas it has reached 10,000 to 20,000 hours for high-speed machines. Because of this, it is necessary to consider maintenance as a consumable item and to reduce maintenance costs.

The spindle device 80 disclosed in Patent Document 1 is configured so that the spindle main body 85 can be pulled out to improve maintainability. However, in this configuration, although the spindle body 85 comes off, there is no description regarding replacement of the rear bearing 93 which is a cylindrical roller bearing, and if the rear bearing 93 is damaged, the maintenance work is the same as in the related art. In addition, since the protrusion of the lubrication nozzle is not provided to remove the spindle main body 85, the running-in operation of the rear bearing 93 is inevitably required to be performed for about 2 to 10 hours after assembling. There was a problem.
Further, in the spindle device disclosed in Patent Document 2, when removing the spindle, the pipe 73 is turned around to remove the pipe 73, and when assembling, it is necessary to further align the phases of the bearing case 33 and the pipe 73. There was a problem that workability was poor.

  The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a low-cost spindle device that can be easily assembled and removed during maintenance.

  1) A spindle device according to the present invention includes an outer cylinder having a stator, a rotatable rotating shaft having a rotor, a front bearing in which an outer ring is fixed to a front housing and an inner ring is externally fitted to one end of the rotating shaft. A bearing sleeve disposed on the other end side of the rotating shaft and fitted to the outer cylinder and movable in the axial direction of the rotating shaft; and an inner ring externally fitted to the other end of the rotating shaft and the outer ring is A rear bearing that is fixed to a bearing sleeve and cooperates with the front bearing to rotatably support the rotating shaft, the inner peripheral diameter of the outer cylinder; The diameter decreases in the order of the inner diameter and the outer diameter of the bearing sleeve, so that the front housing, the subassembly including the rotating shaft and the bearing sleeve can be removed from the outer cylinder, and the rear part from the bearing sleeve. Any cross section Definitive rotator diameter, smaller than the smallest diameter of the non-rotating member in between said bearing sleeve rear end of the cross section, is characterized in that.

  Here, as the front side bearing, a double row combination angular contact ball bearing can be exemplified. In addition, a pair of angular ball bearings can be exemplified as the rear bearing.

In the spindle device configured as described above, the subassembly including the front housing, the rotating shaft, and the bearing sleeve can be extracted from the outer cylinder. Therefore, the assembling property is improved, and it can be quickly replaced when it is damaged. Further, since the rear side bearing of the bearing sleeve is assembled, the state of the grease does not change when the sub-assembly is inserted or removed.
Therefore, in this spindle device, the subassembly is preliminarily operated by using another outer cylinder and then stocked, so that the subassembly can be replaced when the rotating shaft is broken, and normal operation can be immediately performed. Thus, downtime can be greatly reduced. Further, the cost can be reduced as compared with replacing the entire spindle device, and the inventory cost can be reduced. As a result, it is possible to solve the problem of the conventional grease lubrication that cannot reduce the maintenance work and the need for running-in of the bearing after installation, resulting in a longer downtime.

  Also, the diameter becomes smaller in the order of the inner diameter of the outer cylinder, the inner diameter of the stator, and the outer diameter of the bearing sleeve, so that the non-rotating body does not become an obstacle when trying to pull out the subassembly behind the bearing sleeve. The diameter of the rotating body in an arbitrary cross section is smaller than the minimum diameter of the non-rotating body between the rear end of the bearing sleeve and the cross section so that the non-rotating body does not hinder the rotating body. Therefore, when trying to remove the sub-assembly, the non-rotating body, such as the piston mechanism, which holds and releases the tool, does not become an obstacle.

  2) The spindle device according to the present invention includes an outer cylinder having a stator, a rotatable rotating shaft having a rotor, a front bearing in which an outer ring is fixed to a front housing and an inner ring is externally fitted to one end of the rotating shaft. A bearing sleeve disposed on the other end side of the rotating shaft and fitted to the outer cylinder and movable in the axial direction of the rotating shaft; and an inner ring externally fitted to the other end of the rotating shaft and the outer ring is A rear bearing fixed to a bearing sleeve and rotatably supporting the rotating shaft in cooperation with the front bearing, wherein the front housing, the rotating shaft and the bearing are provided. A subassembly consisting of a sleeve can be extracted from the outer cylinder, a tool exchangeable inner diameter part is incorporated in the rotary shaft, and a piston mechanism for tool exchange is provided.

In the spindle device configured as described above, the subassembly including the front housing, the rotating shaft, and the bearing sleeve can be extracted from the outer cylinder. Therefore, the assembling property is improved, and it can be quickly replaced when it is damaged. Further, since the rear side bearing of the bearing sleeve is assembled, the state of the grease does not change when the sub-assembly is inserted or removed.
Therefore, in this spindle device, the subassembly is preliminarily operated by using another outer cylinder and then stocked, so that the subassembly can be replaced when the rotating shaft is broken, and normal operation can be immediately performed. Thus, downtime can be greatly reduced. Further, the cost can be reduced as compared with replacing the entire spindle device, and the inventory cost can be reduced.
In addition, since the tool is exchanged through the piston mechanism by the inner diameter part incorporated in the rotary shaft, the tool exchange can be performed with higher lubrication performance than that exposed outside.

  3) The spindle device according to 2), wherein the distance between the reference mounting surface of the sub-assembly and the piston pressing surface of the inner diameter component is within ± 0.1 mm of a reference dimension. It is characterized by being adjusted to.

  In this case, since the unclamping can be performed appropriately, it is not necessary to adjust the piston when replacing the subassembly, so that the maintenance can be improved.

  4) In the spindle device of the present invention, in the spindle device described in 2), the inner diameter component is incorporated so that a spring can be compressed, and an adjustment component is fixed to a rear portion of the inner diameter component. The adjustment component is characterized in that a piston pressing surface against the piston mechanism is formed.

  With this configuration, the tool holder pressing amount can be set to a predetermined value by the adjustment component. By adjusting the tolerance, unclamping can be performed appropriately, and as a result, When performing replacement, piston adjustment is not required, thereby improving maintainability.

  5) The spindle device according to any one of 1) to 4), wherein the front housing is fitted to the outer cylinder by interference fit. And

  In this case, when the subassembly is disassembled, assembled, or replaced, the axial center between the front housing and the outer cylinder does not shift, and high accuracy can be maintained.

  6) In the spindle device according to the present invention, in the spindle device according to any one of 1) to 5), the bearing sleeve is fitted in a sleeve housing, and the outer diameter of the bearing sleeve is the same as that of the spindle device. It is characterized in that it is fitted with a clearance fit to the inner diameter of the sleeve housing.

  In this case, the role of the rear bearing and the bearing sleeve is to mainly support the rotating shaft, but the axial displacement such as the thermal expansion due to the heat generated by the rotor can be absorbed with a simple structure.

  7) The spindle device according to 6), wherein a plurality of pairs of O-rings are interposed between the outer diameter of the bearing sleeve and the inner diameter of the sleeve housing.

  In this case, a plurality of pairs of O-rings between the outer diameter of the bearing sleeve and the inner diameter of the sleeve housing prevent the leakage of the lubricant, and the vibration of the bearing sleeve can be attenuated by the damping effect of the interference of the O-ring. .

  8) The spindle device according to the present invention, in the spindle device according to any one of 1) to 7), wherein a fitting length between the bearing sleeve and the sleeve housing, an outer diameter of the bearing sleeve, Is set in the range of fitting length / outer diameter = 0.45 to 0.8.

  With this configuration, the outer diameter of the bearing sleeve and the length of the fitting portion to the sleeve housing are set in an appropriate relationship, so that the structure of the subassembly excellent in maintainability and performance as a machine tool is provided. Obtainable.

  9) The spindle device according to any one of 1) to 8) above, wherein a plurality of lubricant discharge holes are provided on a circumference of the bearing sleeve, and an outer periphery of the bearing sleeve. Are provided with a circumferential groove provided on the fitting surface and a lubricant supply path in a radial direction connected to and connected to the circumferential groove.

  In this way, it is possible for the bearing sleeve to discharge the lubricant without problems in any phase. For example, a horizontally mounted spindle would require a drain hole on the bottom, but any of the holes would point to the bottom to allow for drain. In addition, the lubricant can be supplied at any position by the bearing sleeve. Therefore, it is not necessary to match the phases of the bearing sleeves, and the workability of maintenance is good.

  10) The spindle device according to any one of 1) to 9), wherein the rear bearing is an angular ball bearing having a fixed preload and a rear combination. And

  In this way, axial displacement such as thermal expansion due to heat generated by the rotor can be absorbed with a simple structure.

  11) The spindle device according to the present invention is characterized in that the spindle device according to any one of 1) to 10) is grease-lubricated.

  In this way, the maintenance can be performed at low cost by easy handling and relatively inexpensive grease lubrication.

  12) A spindle device according to the present invention is the spindle device described in any one of 1) to 11) above, further including a grease replenishing device.

  With this configuration, the grease replenishing device can make up for the shortage of grease, so that seizure or the like can be avoided.

  13) The spindle device according to any one of the above 1) to 10) or the spindle device according to claim 12, further comprising a mechanism for discharging excess grease after grease is supplied. Features.

  In this case, the lubricant that is supplied to the inside of the bearing and becomes unnecessary is attached to a rotating member such as an outer ring spacer disposed near the bearing, and the lubricant attached to the rotating member is applied to the bearing by the rotating force. It is flipped out. Thereby, the unnecessary lubricant can be forcibly discharged to the outside of the bearing.

  14) The spindle device according to the present invention is characterized in that, in the spindle device according to any one of 1) to 10), any one of oil-air, oil mist, and direct injection lubrication is used in a small amount. .

  With this configuration, efficient lubrication can be performed by any of a small amount of oil air, oil mist, and direct injection lubrication, so that seizure resistance can be further improved.

  According to the present invention, it is possible to provide a low-cost spindle device that can be easily assembled and removed during maintenance, can be operated immediately after replacement, and is inexpensive.

  Hereinafter, a plurality of preferred embodiments according to the present invention will be described in detail with reference to the drawings. 1 is a longitudinal sectional view of a first embodiment of a spindle device according to the present invention, FIG. 2 is a longitudinal sectional view showing a subassembly of the spindle device shown in FIG. 1, FIG. 3 is a front view showing a rear cover in FIG. 4 is a longitudinal sectional view of a second embodiment of the spindle device according to the present invention, FIG. 5 is a longitudinal sectional view showing a subassembly of the spindle device shown in FIG. 4, and FIG. 6 is a tool anchor of the spindle device shown in FIG. FIG. 7 is a vertical sectional view in a clamped state, FIG. 7 is an assembly view of the spindle device shown in FIG. 4 with an automatic tool changer, and FIG. 8 is a longitudinal section showing a third embodiment of a spindle device according to the present invention. FIG. 9 is a longitudinal sectional view showing a state in which the subassembly shown in FIG. 8 is inserted into the outer cylinder. FIG. 10 is a characteristic diagram of bearing dimensions and surface pressure in the spindle device shown in FIG. (A) is a front view of a bearing sleeve in a fourth embodiment of a spindle device according to the present invention, and (b) of FIG. 11 is a longitudinal section of (a). , 12 FIG. 11 (a), an essential part longitudinal cross sectional view showing a modified example of (b).

  As shown in FIG. 1, a main spindle device 1 according to a first embodiment of the present invention includes an outer cylinder 3 having a stator 4 and a sleeve housing 5, a rotatable rotary shaft 6 having a rotor 7, and an outer ring having a front housing. And a front side bearing 12 which is a combined angular ball bearing in which the inner ring is fitted to one end of the rotary shaft 6 while being fixed to the rotating shaft 6. A bearing sleeve 11 disposed on the other end of the rotating shaft 6 and fitted in the sleeve housing 5 and movable in the axial direction of the rotating shaft 6; And a rear bearing 13, which is a pair of angular ball bearings, fixed to the bearing sleeve 11 and cooperating with the front bearing 12 to rotatably support the rotating shaft 6. Reference numeral 14 denotes a piston mechanism for tool change. Note that the sleeve housing 5 and the outer cylinder 3 may have an integral structure.

  As shown in FIG. 2, the subassembly 2 including the front housing 8, the rotating shaft 6, and the bearing sleeve 11 is configured to be able to be extracted from the outer cylinder 3. That is, in the spindle device 1 of the present embodiment, the diameter decreases in the order of the inner diameter φA of the outer cylinder 3, the outer diameter φB of the rotor 7, and the outer diameter φC of the bearing sleeve 11 (φA> φB> φC). Further, instead of the rotor outer diameter φB, the stator inner diameter φB ′ (see FIG. 1) may be set to satisfy φA> φB ′> φC. In a range L behind the bearing sleeve 11, the outer diameter of the subassembly 2 is set smaller than the outer diameter of the bearing sleeve 11. That is, when trying to pull out the main shaft in the direction of arrow M, the outer diameter of the main shaft rotating body in an arbitrary cross section of the range L is set so that the non-rotating body does not hinder the non-rotating body. The outer diameter of the rotating body is defined so as to be smaller than the minimum inner diameter of the rotating body so that the non-rotating body does not hinder the rotating body. Therefore, when trying to pull out the sub-assembly 2 in the direction M in the figure, the piston mechanism 14 or the like, which is a non-rotating body that holds / opens the tool W attached to the left end in the figure, does not become an obstacle. .

  In the spindle device 1, the outer diameter of the bearing sleeve 11 is a clearance fit of 5 to 30 μm with respect to the inner diameter of the sleeve housing 5. Further, in the spindle device 1, the rear bearing 13 is an angular contact ball bearing having a fixed preload and a rear combination. Thus, although the role of the rear bearing 13 and the bearing sleeve 11 is to mainly support the rotating shaft 6, axial displacement such as thermal expansion due to heat generated by the rotor can be absorbed with a simple structure.

  In the spindle device 1, the spigot portion 15 between the front housing 8 and the inner peripheral surface of the outer cylinder 3 is a tight fit of 0 to 20 μm. Thus, the axial center of the front housing 8 and the axis of the outer cylinder 3 do not shift. In addition, the mating surface 16 is finished with high precision at a right angle of 2 to 5 μm or less with respect to the axis of the front housing 8 and the outer cylinder 3. Thereby, even if the length LR of the spigot part 15 is short, the axes of the two coincide. If the length of the spigot part 15 is long, the assembling property is poor, but in the present embodiment, the spigot length LR is set to be as short as about 1/10 to 1/30 of the spigot diameter φA. Further, since the length LR of the spigot portion 15 is short, it can be easily tightened by the mounting bolt 17 and assembled. This eliminates the need for alignment work.

  The subassembly 2 has labyrinth seals L1 to L4 formed between the subassembly 2 and the outside air. When the spindle is used, strong labyrinths L1 and L4 prevent foreign matter such as cutting water and chips from entering. When only the subassembly 2 is stocked, foreign substances such as dust are blocked by the labyrinths L1 to L4. The labyrinths L2 and L3 play a role in preventing foreign matter from entering even when the subassembly is replaced for maintenance. During maintenance, the labyrinths L2 and L3 are useful because an environment with few foreign substances such as a clean room cannot be expected. The structures of the labyrinths L3 and L4 can be realized by using the bearing sleeve 11.

  As shown in FIG. 3, the rear part of the rear cover 9 has seven wirings (motor power line 25, motor temperature sensor line 26, rotary encoder line 27, etc.) and 14 pipes (bearing lubricating oil pipe 21, cooling oil pipe 22, tool Since the unclamping hydraulic pipe 23, the tool taper air blow pipe 24, and the air seal pipe 28) are connected to the outside, there is no need to handle them at the time of maintenance, so the downtime is very short and the maintainability is good.

  According to the spindle device 10 described above, the subassembly 2 including the front housing 8, the rotating shaft 6, and the bearing sleeve 11 can be extracted from the outer cylinder 3. Therefore, the assembling property is improved, and it can be quickly replaced when it is damaged. Since the bearing sleeve 11 is in a state where the rear bearing 13 is assembled, the state of the grease does not change when the semi-assembly 2 is inserted or removed. Therefore, by sublimating the subassembly 2 beforehand using another outer cylinder and performing inventory operation, the subassembly can be replaced when the rotating shaft is broken, and normal operation can be immediately performed, thereby greatly reducing downtime. It is possible to shorten the time. Further, the cost can be reduced as compared with replacing the entire spindle device 1, and the inventory cost can be reduced.

  Next, a second embodiment of the spindle device according to the present invention will be described with reference to FIGS. In each of the following embodiments, members having the same configuration and operation as those already described are denoted by the same or corresponding reference numerals in the drawings to simplify or simplify the description. Omitted.

  As shown in FIG. 4, a spindle device 30 according to a second embodiment of the present invention includes two springs 32 in a rotating shaft 6 that rotates together with a rotor 7 when electricity is supplied to a stator 4 of an outer cylinder 3. An inner diameter component (also referred to as a drawbar) 31 that is compressible and can be exchanged with a tool is incorporated, and an inner diameter component side adjustment component 33 is attached to a rear end of the inner diameter component 31. A piston pressing surface 34 against the piston mechanism 14 is formed at an end of the inner-diameter component-side adjustment component 33. At the end of the piston 35 of the piston mechanism 14, a piston-side adjusting component 36 that presses the inner-diameter component-side adjusting component 33 is mounted.

  When a pressure medium such as oil, water, or air is introduced into the forward-movement-side pressure introducing portion 37, the piston mechanism 14 moves the piston 35 forward, and the piston-side adjustment component 36 of the piston 35 becomes the inner-diameter component-side adjustment component. 33, the piston pressing surface 34 is pressed, the inner diameter part 31 is pressed and moved in the axial direction, and the tool W is pushed out to be in a tool unclamped state. On the other hand, the pressure of the forward-side pressure introducing portion 37 is released, and the pressure medium is introduced into the backward-side pressure introducing portion 38, whereby the piston 35 is moved backward, and the inner diameter part 31 is moved back in the axial direction. Then, the tool is clamped.

  As shown in FIG. 5, the inner diameter part-side adjusting part 33 adjusts the axial dimension (distance) Z between the mounting reference surface 39 of the sub-assembly 2 and the piston pressing surface 34 of the inner diameter part 31 with respect to the reference dimension. It can be adjusted within 0.1 mm. That is, the subassembly 2 has a dimensional difference due to the stacking of many components within the axial dimension Z from the mounting reference surface 39 to the piston pressing surface 34 of the inner diameter component 31. Therefore, if there is no adjustment in advance, it is necessary to perform the piston stroke adjustment work on site at the time of maintenance. For example, if the movement amount (extrusion amount) of the inner diameter part 31 decreases due to insufficient piston stroke, the tool holder cannot be unclamped. Conversely, if the moving amount of the inner diameter part 31 is too large, the inner diameter part 31 pushes the tool holder excessively forward, so that the automatic tool changer (ATC) 40 (see FIG. 7) holds the tool holder. I can't do anything. On the other hand, the inner diameter component side adjustment component 33 sets the tool holder pushing amount (the amount by which the tool holder is pushed out of the gripping position by the inner diameter component 31 when the piston 35 is pushed to the front end) from 0.4 mm to 0.1 mm. 6 mm, the tolerance is adjusted to within ± 0.1 mm, which is about 0.1 mm to 0.2 mm, so that unclamping can be performed appropriately. As a result, when replacing a subassembly, Maintenance can be improved by eliminating the need for piston adjustment.

  Here, the adjustment by the inner diameter part-side adjusting part 33 is prepared by a method of cutting (turning, grinding) with a margin in advance after dimension measurement, a method of sandwiching shims having different thicknesses in the gap S, or a method prepared in advance. There are a method of selecting an adjustment plate having several dimensions, a method of arranging the adjustment plate at a desired position with an adjustment screw, and fixing the adjustment plate with an anaerobic adhesive or the like. In order to directly measure the axial dimension Z, a large jig is required. In some cases, a heavy subassembly must be set in the jig. In some cases, a certain degree of dimensional control may be applied to each part. For example, the dimensions A and B (both the inner ring spacer and the outer ring spacer), the difference width C and the dimension D of the rearmost inner and outer rings of the front bearing 12 are managed, and the inner diameter part 31 is attached to the rotating shaft 6. There is a method of measuring and adjusting only the dimension ZZ in the attached state. This method can reduce the cost of dimensional management because it is not necessary to control the axial dimension of the inner diameter portion of the shaft, which is the most difficult to control (various dimensions of the collet portion, access to the tool taper, hole depth of the inner diameter part 31, etc.), The burden of adjustment work is also small. In order to simplify the management of the differential width C, a universal combination bearing in which the front and rear differential widths are individually adjusted may be used for the four rows of the front bearings 12.

As shown in FIGS. 4 to 6, the tool holder pushing amount (see FIG. 5) E is adjusted using the subassembly 2 in which the axial dimension Z is controlled.
Tool holder pushing amount E = (piston stroke F)-(space G)-(space H)
Then, the respective amounts on the right side are measured, or the actual amount is unclamped and the pressing amount E (the amount by which the tool holder advances) is measured. Then, here, the piston-side adjustment component 36 is adjusted so that E = 0.5 ± 0.1 mm. This determines the axial position of the clamp / unclamp stroke. As a result, if the mutually adjusted subassembly 2 is replaced thereafter, the positional relationship between the piston 35 and the inner diameter part 31 does not change, so that the adjustment of the piston portion can be omitted.

  By doing so, the subassembly 2 has a tolerance of the tool holder pushing amount E of 0.1 mm to 0 with respect to the tolerance of the axial dimension Z from the mounting reference surface 39 to the piston pressing surface 34 of the inner diameter part 31. .2 mm. When assembling the piston mechanism 14 for tool change, the piston stroke F is adjusted in accordance with the controlled subassembly 2. Thereby, if the units of the subassembly 2 whose axial dimension Z is controlled are replaced during maintenance, the axial phase relationship of the piston pressing surface 34 of the inner diameter part 31 does not change, so that the piston stroke need not be readjusted. Become. Further, since the axial dimension Z is determined by the stacking of a large number of components, the axial dimensional tolerances of these components may be set individually, and the stacked values may be managed so as to be equal to or less than a desired value. However, satisfying the tolerance of 0.1 to 0.2 mm in such a method, specifically, stacking dimensional tolerances of 10 or more, leads to an increase in cost and an increase in the defective rate. Often it becomes. Therefore, by adjusting the inner diameter part-side adjustment part 33 after the inner diameter part 31 is assembled after the inner diameter part 31 is assembled, the axial dimension Z can be managed at a very low cost.

  As shown in FIG. 6, the piston mechanism 14 causes the piston 35 to move forward when the pressure medium is introduced into the forward movement side pressure introduction unit 37, and the piston side adjustment component 36 The piston pressing surface 34 is pressed, and the inner diameter part 31 is pressed and moved in the axial direction against the spring 32 to push out the tool W to bring the tool into an unclamped state.

  As shown in FIG. 7, at the time of automatic tool change of the spindle device 30, the operation of the automatic tool changer 40 is very fast for improving efficiency, and the change time is usually about 0.2 seconds. . Therefore, it is necessary to keep the strength and rigidity of each part high. After the arm 41 grips the rotary shaft 6 and the tool holder 43 of the tool magazine 42, the automatic tool changing device 40 unclamps the tool W of the rotary shaft 6, and the arm 41 moves up and down and pivots to perform tool change. Behave as if When the rotary shaft 6 is unclamped by gripping the tool W, if the pressing amount of the tool holder 43 is too large, the tool holder 43 has high rigidity and is gripped by the arm 41 as described above, so that the arm 41 cannot hold the tool W. Load on the automatic tool changer 40. Therefore, the pressing amount of the tool holder 43 needs to be 0.5 to 0.6 mm or less. In the spindle device 30, even if the subassembly 2 is replaced by performing maintenance, the pressing amount of the tool holder 43 does not change, so that the replacement can be performed in a short time without adjustment work.

Next, a third embodiment of the spindle device according to the present invention will be described with reference to FIG. In FIG. 8, the upper half in the figure shows a tool unclamped state, and the lower half in the figure shows a tool clamped state.
As shown in FIG. 8, a spindle device 50 according to a third embodiment of the present invention uses inner diameter parts 51 having different taper angles for the subassembly 2. At this time, for the inner diameter part for the BT holder (JIS B6339) and the HSK holder (ISO-12164), the target value Z1 for the axial dimension Z to be managed varies depending on the tool taper standard. It has been adjusted to be compatible with that shown in FIG. That is, the axial dimension Z _UC2 when unclamped is adjusted to be the same as the unclamped state Z _UC1 shown in FIG. In addition, the space G in FIG. 4 is set to a value larger than the minimum necessary amount for unclamping the BT holder in order to apply to the inner diameter parts having different axial dimensions Z as described above. Various tool taper standards may be used depending on the application, but as shown in this example, compatibility is provided so that unclamping is possible even with different tool standards, making it easy to change specifications and maintain The cost can be reduced by facilitating inventory management of the inner cartridge for the purpose.

  As shown in FIG. 9, in the spindle device 30, the ratio between the outer diameter I of the bearing sleeve 11 and the length J of the fitting portion is J / I ≒ 0.5. In this case, the relationship between the outer diameter I and the length J is preferably set to 0.45 to 0.8. When inserting the sub-assembly 2 into the outer cylinder 3, first, the bearing sleeve 11 is fitted into the inner diameter of the sleeve housing 5. Since the replacement of the subassembly 2 is usually performed at the work site of the machine tool user, it is often impossible to use a special jig for the replacement work. In such a case, when the sub-assembly 2 receives a force in the direction of arrow K such as its own weight, a moment load is applied to the rear bearing 13. At this time, if the length J is small, the span M of the two rows of the rear-side bearings 13 becomes short, and the contact surface pressure becomes large, so that the rear-side bearings 13 may be damaged.

  As shown in FIG. 10, in the spindle device 30, the relationship between the J / I and the bearing span described above and the relationship between the bearing contact surface pressure when the load K is applied were examined. The load K is the weight of the sub-assembly 2 and is a load that is generated by handling at the time of assembling in a field replacement operation where a jig cannot be used. The rear bearing 13 is an angular ball bearing having an inner diameter of φ55 mm. It is known that indentation occurs at a contact surface pressure of a bearing of 3.5 GPa or more in bearing steel having a hardness of Hv = 700. From these, it is understood that J / I ≧ 0.45 is required. If the span of the rear bearing 13 is too long, the performance as a machine tool cannot be improved, and problems such as an increase in the inertia moment of the shaft (increase in acceleration / deceleration time) and a decrease in the resonance point occur. , J / I ≦ 0.8. Further, by setting the relationship of J / I as described above, it is possible to provide an O-ring (O-ring) having a vibration damping function described later without causing a sliding defect. As described above, by setting the relationship between the outer diameter I of the bearing sleeve 11 and the length J of the fitting portion and appropriately designing the same, the subassembly 2 having excellent maintainability and performance as a machine tool. Can be obtained.

Next, with reference to FIGS. 11A and 11B, a fourth embodiment of the spindle device according to the present invention will be described.
As shown in FIGS. 11 (a) and 11 (b), a spindle device 60 according to a fourth embodiment of the present invention includes a rear bearing 13 provided with a lubrication supply and discharge structure. In order to enable easy detachment and assembly of the device, it is necessary to determine the phase.
The bearing sleeve 11 is clearance-fitted to the inner diameter of the sleeve housing 5 (see FIG. 6). Accordingly, the bearing sleeve 11 easily rotates with respect to the rotating shaft 6 in a state where the inner diameter part 31 is assembled. Therefore, conventionally, when the lubricant is supplied to the rear bearing 13, projections such as nozzles and keys are provided to determine the supply phase and the lubricant discharge hole phase. For this reason, there is a problem that the assembly and separation of the sub-assembly 2 cannot be performed unless the phase is adjusted and the protruding parts are not inserted and removed, and maintenance is difficult. On the other hand, since the subassembly 2 is not provided with a projection such as a lubricating nozzle from the outer peripheral side, the subassembly 2 can be removed only by removing the mounting bolt 17.

  The lubrication supply structure is formed in the radial direction of the sleeve housing 61, and a lubrication supply inlet (lubricant supply path) 62 communicatively connected to a lubricant supply device (not shown) and a fitting surface on the outer periphery of the bearing sleeve 63. Through the outer ring of the rear-side bearing 13 through a circumferential groove 64 provided in the bearing sleeve 63 and a radial hole (lubricant supply path) 65 formed radially in communication with the circumferential groove 64 in the bearing sleeve 63. A lubricant is supplied into the bearing space. The sleeve housing 61 and the bearing sleeve 63 have their front ends sealed with front O-rings (O-rings) 66, 66, and their rear ends sealed with rear O-rings 67, 67. At this time, even if the lubricant supply paths in the radial direction of the sleeve housing 61 and the bearing sleeve 63 are in the same phase, or both are rotating in the opposite phase by 180 °, the rear side bearing is formed by the circumferential groove 64. 13 is supplied with lubricating oil smoothly. The circumferential groove 64 may be provided on the inner periphery of the sleeve housing 61.

  The discharge structure includes outer ring spacers 68, 68 disposed between the rear-side bearings 13, radial discharge holes 69, 69, 69 formed radially in the outer ring retainer 68 </ b> A and the bearing sleeve 63, and a bearing. A plurality of axial discharge holes 70 formed in the axial direction of the sleeve 63 so as to communicate with the radial discharge holes 69, 69, 69, and a plurality of the axial discharge holes 70 communicated with the axial discharge holes 70 at equal intervals in the circumferential direction of the bearing sleeve 63. And six lubricant discharge holes 71, 71, 71, 71, 71, 71. Since the six lubricant discharge holes 71 are arranged evenly, at least one lubricant discharge hole 71 is secured within ± 15 ° immediately below in any phase, so that the discharge at the time of horizontal mounting is ensured. Has become possible.

  The lubrication supply and discharge structure has a function of discharging excess grease after grease is supplied. As a result, the unnecessary lubricant supplied to the inside of the bearing is repelled to the outside of the bearing by the rotational force of the slinger portion 68B shown in FIG. As a result, it is possible to discharge the lubricant without any problem at any phase.For example, a horizontally mounted spindle requires a discharge hole on the lower side, but it can be discharged because any hole faces downward. it can. In addition, since grease lubrication is used, handling is easy, and maintenance can be performed at low cost by relatively inexpensive grease lubrication. In addition, since a lubricant supply device (grease replenishing device) is provided, shortage of grease can be compensated, so that seizure or the like can be avoided. Further, any one of lubrication of oil air, oil mist, and direct injection lubrication may be used. Then, since efficient lubrication can be performed, seizure resistance can be further improved.

  In order to prevent the O-ring from being cut when inserting or removing the bearing sleeve 63 between the sleeve housing 61 and the bearing sleeve 63, front O-rings 66, 66 are arranged on the outer periphery on the front side of the bearing sleeve 63. Rear O-rings 67, 67 are disposed on the inner periphery of the rear side. Thereby, when the bearing sleeve 63 slides on the inner periphery of the sleeve housing 61 by insertion or removal of the sub-assembly 2, the sliding distance of each O-ring 66, 66, 67, 67 is minimized, and the O-ring is cut off. Since the O-rings 66, 66, 67, 67 do not pass through the steps or holes that are factors, the reliability of the O-rings 66, 66, 67, 67 can be significantly improved.

  Each of the O-rings 66, 66, 67, 67 uses a large number of O-rings, two on the front end and two on the rear end. This aims at damping the vibration of the bearing sleeve 63 by the damping effect of the interference of the O-rings 66, 66, 67, 67. Since the bearing sleeve 63 is fitted into the sleeve housing 61 with a gap, the bearing sleeve 63 vibrates in the gap without a damping element such as an O-ring. This is because the cutting performance and accuracy may be deteriorated, and the inner diameter of the sleeve housing 61 or the outer diameter of the bearing sleeve 63 may be frettingly worn. If fretting wear occurs, the vibration will increase further, or a sliding failure will occur, and in order to repair the wear, the entire spindle device must be replaced. In addition, since the use of a plurality of O-rings increases the restraining force, the bearing sleeve 63 does not rotate freely in the rotation direction, so that creep can be prevented, and creep wear of the fitting surface can be prevented. As described above, further effects can be obtained by using a plurality of O-rings.

  As shown in FIG. 12, in the modified example of FIGS. 11A and 11B, only the rear side of the bearing sleeve 63 is a single O-ring 72 having a small diameter. By doing so, the number of O-rings can be reduced, and the O-rings can be arranged compactly. However, FIGS. 11A and 11B are superior in that the bearing sleeve 63 does not receive an axial force due to the pressure of the lubricant.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

It is a longitudinal section of a 1st embodiment of a spindle device concerning the present invention. FIG. 2 is a longitudinal sectional view showing a sub-assembly in the spindle device shown in FIG. 1. FIG. 2 is a front view showing a rear cover in FIG. 1. It is a longitudinal section of a 2nd embodiment of a spindle device concerning the present invention. FIG. 5 is a longitudinal sectional view showing a sub-assembly of the spindle device shown in FIG. 4. FIG. 5 is a longitudinal sectional view of the spindle device shown in FIG. 4 in a tool unclamping state. FIG. 5 is an assembly diagram of the spindle device shown in FIG. 4 and an automatic tool changer. It is a longitudinal section showing the subassembly of a 3rd embodiment of a spindle device concerning the present invention. FIG. 9 is a longitudinal sectional view showing a state in which the sub-assembly shown in FIG. 8 is inserted into an outer cylinder. FIG. 10 is a characteristic diagram of bearing dimensions and surface pressure in the spindle device shown in FIG. 9. (A) is a front view of a bearing sleeve in a fourth embodiment of a spindle device according to the present invention, and (b) is a longitudinal sectional view of (a). It is a principal part longitudinal cross-sectional view which shows the modification of FIG.11 (a), (b). It is a longitudinal section showing the conventional spindle device.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1, 30, 40, 50, 60 Spindle device 2 Subassembly 3 Outer cylinder 4 Stator 5, 61 Sleeve housing 6 Rotating shaft 7 Rotor 8 Front housing 9 Rear cover 11, 63 Bearing sleeve 12 Front side bearing 13 Rear side bearing 14 Piston Mechanism 31 Inner diameter part 32 Spring 33 Inner diameter part side adjustment part (adjustment part)
34 Piston 39 Reference mounting surface 62 Lubricant supply inlet (lubricant supply path)
64 Circumferential groove 65 Radial hole (lubricant supply path)
66 Front O-ring (O-ring)
67 Rear O-ring (O-ring)
71 Lubricant discharge hole 72 O-ring

Claims (14)

An outer cylinder having a stator,
A rotatable rotating shaft having a rotor,
A front bearing in which an outer race is fixed to the front housing and an inner race is fitted to one end of the rotating shaft;
A bearing sleeve disposed on the other end of the rotating shaft and fitted in the outer cylinder and movable in the axial direction of the rotating shaft;
A rear bearing in which an inner ring is fitted to the other end of the rotating shaft and an outer ring is fixed to the bearing sleeve and cooperates with the front bearing to rotatably support the rotating shaft;
A spindle device comprising:
The diameter decreases in the order of the inner diameter of the outer cylinder, the inner diameter of the stator, and the outer diameter of the bearing sleeve, and the subassembly including the front housing, the rotating shaft, and the bearing sleeve is removed from the outer cylinder. A spindle device which is possible and has a rotating body diameter in an arbitrary cross section behind the bearing sleeve is smaller than a minimum diameter of a non-rotating body between the rear end of the bearing sleeve and the cross section. An outer cylinder having a stator,
A rotatable rotating shaft having a rotor,
A front bearing in which an outer race is fixed to the front housing and an inner race is fitted to one end of the rotating shaft;
A bearing sleeve disposed on the other end of the rotating shaft and fitted in the outer cylinder and movable in the axial direction of the rotating shaft;
A rear bearing in which an inner ring is fitted to the other end of the rotating shaft and an outer ring is fixed to the bearing sleeve and cooperates with the front bearing to rotatably support the rotating shaft;
A spindle device comprising:
The front housing, a subassembly including the rotating shaft and the bearing sleeve can be removed from the outer cylinder,
A main spindle device, wherein a tool-exchangeable inner diameter part is incorporated in the rotary shaft, and a piston mechanism for tool exchange is provided.   The spindle device according to claim 2, wherein a distance between a reference mounting surface of the subassembly and a piston pressing surface of the inner diameter component is adjusted within ± 0.1 mm from a reference dimension.   The inner diameter component is incorporated so that a spring can be compressed, and an adjusting component is fixed to a rear portion of the inner diameter component, and the adjusting component has a piston pressing surface against the piston mechanism. 3. The spindle device according to claim 2, wherein:   The spindle device according to any one of claims 1 to 4, wherein the front housing is fitted to the outer cylinder by interference fit.   6. The bearing sleeve according to claim 1, wherein the bearing sleeve is fitted inside the sleeve housing, and an outer diameter of the bearing sleeve is fitted to the inner diameter of the sleeve housing by a clearance fit. A spindle device according to claim 1.   The spindle device according to claim 6, wherein a plurality of pairs of O-rings are interposed between the outer diameter of the bearing sleeve and the inner diameter of the sleeve housing.   The ratio between the fitting length of the bearing sleeve and the sleeve housing and the outer diameter of the bearing sleeve is set in a range of fitting length / outer diameter = 0.45 to 0.8. The spindle device according to any one of claims 1 to 7, characterized in that:   A plurality of lubricant discharge holes provided on the circumference of the bearing sleeve, a circumferential groove provided on a fitting surface of the outer periphery of the bearing sleeve, and a radial lubricant supply connected to the circumferential groove; The spindle device according to any one of claims 1 to 8, further comprising: a path.   The spindle device according to any one of claims 1 to 9, wherein the rear-side bearing is a fixed-position preload and back-to-back angular ball bearing.   The spindle device according to any one of claims 1 to 10, wherein the spindle device is grease lubrication.   The spindle device according to any one of claims 1 to 11, further comprising a grease replenishing device.   The spindle device according to any one of claims 1 to 10, further comprising a mechanism for discharging excess grease after grease is supplied.   The spindle device according to any one of claims 1 to 10, wherein a slight amount of lubrication is selected from oil air, oil mist, and direct injection lubrication.

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