JP3612923B2 - Spindle head device in machine tools - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spindle head device for a machine tool that preferably supports a spindle that rotates at high speed while holding a cutting tool or a work piece by a bearing, and in particular, supplies and supplies a lubricating liquid for lubricating the bearing. The present invention relates to a spindle head device having an improved recovery path.
[0002]
[Prior art]
In general, in a cutting machine tool such as a machining center, a tool spindle that holds a cutting tool in a tip opening thereof is rotatably supported in a main body of a spindle head via a rolling bearing. Recently, with the demand for high-efficiency machining of aluminum materials, it is required to rotate the tool spindle at a high speed of about 50,000 revolutions per minute, for example.
[0003]
In a conventional spindle head of this type, a supply passage and a collection passage for a lubricating fluid having a generally circular cross section extending in parallel with the tool spindle are formed in a spindle head body that functions as a bearing housing. Lubricating fluid pumped from the supply port that opens at the rear of the spindle head body is guided to one side of the bearing disposed at the front of the spindle head body through the supply passage, and from this one side as a jet flow, It is ejected between the inner and outer rings to cool and lubricate the ball rolling surface of the bearing, and then is recovered to the lubricating fluid supply device through a recovery passage and opened at the rear part of the spindle head.
[0004]
Here, when the lubricating fluid is a mist-like gas, the plurality of supply passages are arranged in a thermal symmetry around the axis of the tool spindle, and the plurality of recovery passages are arranged in the same thermal symmetry, Thermal deformation of the spindle head due to a temperature difference between the lubricating gas passing through the supply passage and the lubricating gas passing through the recovery passage can be eliminated. In this case, even when the tool spindle is supported horizontally, since the lubricating fluid is a gas, there is no problem in collecting the lubricating gas after cooling the bearing.
[0005]
[Problems to be solved by the invention]
However, when a lubricant such as oil is used as a lubricating fluid in a spindle head device of a horizontal machine tool that horizontally supports the tool spindle, the lubricating oil is naturally flown by arranging the lubricating oil supply / recovery path so as not to run against gravity. Consideration to make it easier to flow is necessary. Specifically, it is required to provide the supply passage in the upper part of the tool spindle and provide the recovery path in the lower part of the tool spindle.
[0006]
When the supply passage and the recovery passage are arranged separately in the upper and lower parts in the housing as described above, a temperature difference occurs in the lubricating oil passing through these passages due to a rise in the temperature of the lubricating oil that has lubricated and cooled the bearing. For this reason, the arrangement of the passages is thermally asymmetric, and the thermal expansion of the part of the spindle head at the upper part of the tool spindle is small but the thermal expansion of the part at the lower part is large. Deform. As a result, when this spindle head device is used, there arises a problem in machining accuracy such as the straightness of the machining hole being impaired.
[0007]
Accordingly, an object of the present invention is to prevent thermal deformation of the spindle head due to the temperature difference of the lubricating fluid passing through these passages even in a configuration in which the supply passage and the recovery passage of the lubricant are thermally asymmetrically arranged in the spindle head. There is to do.
[0008]
[Means for Solving the Problems]
The above-described problems related to the conventional spindle head device and the object of the present invention are solved and achieved by the following means.
In the spindle head device of the present invention, the spindle is rotatably supported in the housing by the first and second bearings spaced apart in the axial direction. The housing is provided with a mounting portion at a position retracted from the first bearing supporting the front end portion of the main shaft to the second bearing side in the main shaft axis direction, and the housing is fixed to a carrier that slides, for example. A supply path for supplying the lubricant to the first bearing from the lubricant supply apparatus and a recovery path for recovering the lubricant supplied to the first bearing to the lubricant supply apparatus are provided on both sides in the radial direction of the main shaft. At least one of the recovery path and the supply path, preferably the recovery path, is connected to the lubricating liquid supply device and opens in the vicinity of the mounting portion, and is formed in the housing from the vicinity of the first bearing. A radial passage that extends in the radial direction, and a relay passage that relays the connection port and the radial passage, and prevents the heat of the lubricating liquid that passes through the passage from being conducted to the housing. Consists of.
[0009]
With such a configuration, it is possible to prevent a temperature difference from occurring on both sides in the radial direction of the housing in the axial portion from the mounting portion to the first bearing, and as a result, on both sides in the radial direction of the housing. A difference in thermal deformation is eliminated.
Preferably, as described in claim 2, the present invention is applied to a spindle head device for a horizontal machine tool in which the spindle is horizontally supported by first and second rolling bearings, and the supply path and the recovery path are connected to the spindle. Arrange on the upper and lower sides respectively. In this case, each of the relay passages of the supply path and the recovery path is constituted by a relay pipe extending in the axial direction of the main shaft, and the relay pipe is connected to the connection port and the radial passage and arranged outside the housing. To do. By disposing the relay pipe outside the housing, heat conduction from the relay pipe to the housing is reliably prevented.
[0010]
As described in claim 3, another embodiment in which the relay pipe is formed of a heat insulating material and embedded in the housing can also be adopted.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2, reference numeral 10 denotes an upright column of a horizontal machining center. A spindle head carrier 12 extends along the Y-axis guide 11 formed on the front surface of the column 10 at both ends in the X-axis direction perpendicular to the paper surface of FIG. And is moved up and down by a feed mechanism (not shown). The carrier 12 has a through hole 12a opened in the Z-axis direction at the center thereof, and the rear cylindrical portion 20a of the spindle head 20 is closely fitted and supported in the through hole 12a.
[0012]
The spindle head 20 has a substantially cylindrical shape, and a flange 20f as a disk-shaped mounting portion is formed on the front side of the rear cylindrical portion 20a. The flange 20f is fixed to the front surface of the carrier 12 with a plurality of bolts 21. .
A housing 22 forming an outer shell of the spindle head 20 is fitted into a housing main body 23 having the rear cylindrical portion 20a, the flange 20f, and a front cylindrical portion 20b extending forward from the front surface of the flange 20f, and a front end opening of the main body 23. The front housing 24 is fixed, and the front cap 25 is fixed to the front end of the front housing 24.
[0013]
The tool spindle 26 is parallel to the Z axis in the housing 22 by a pair of rear rolling bearings 27 a and 27 b housed in the rear part of the housing body 23 and a pair of front rolling bearings 28 a and 28 b housed in the front housing 24. It is supported so that it can only rotate around a horizontal axis. A built-in motor 30 that rotationally drives the tool spindle 26 is accommodated in the housing 22 between the front rolling bearings 28a and 28b and the rear rolling bearings 27a and 27b. The motor 30 is an AC servomotor in which the actual rotational speed follows the speed command value by known inverter control.
[0014]
More specifically, the outer periphery of the stator 31 of the motor 30 is fitted and supported in the inner hole of the main body 23 via the cooling jacket sleeve 32. On the other hand, the rotor (not shown) of the motor 30 is fixed on the tool spindle 26. The jacket sleeve 32 is formed with a spiral coolant passage 35 on the fitting surface with the inner hole of the main body 23, and the motor 30 is cooled by circulating the coolant through the passage 35.
[0015]
The tool spindle 26 has a built-in tool pulling mechanism, clamps the cutting tool T received in the tool mounting hole opened at the front end, and the draw bar 37 of the tool pulling mechanism protruding from the rear end is a piston rod 39 of the release drive cylinder 38. The cutting tool T can be unclamped when pushed forward by. The release drive cylinder 38 is provided in a bracket 40 supported at the rear end of the housing body 23.
[0016]
The present invention is characterized by a lubricating fluid circulation mechanism that supplies lubricating liquid to the front bearings 28a and 28b and collects the lubricating liquid therefrom. This circulation mechanism includes a supply path 46 that guides the lubricating oil supplied from the electric motor M drive type supply pump P1 of the lubricating oil supply device 45 shown in FIG. 1 to the front bearings 28a and 28b, and the rolling bearings 28a and 28b. The recovery path 47 is configured to recover the supplied lubricating liquid by the vacuum action of the recovery pump P2.
[0017]
The supply path 46 is disposed on the upper side of the main spindle head 20 and opens in the rear surface of the housing main body 23, and extends in substantially parallel to the tool main spindle 26 to the flange 20f and is formed in the housing main body 23 (FIGS. 1 and 2). 2 includes only one axial passage 48a, 48b. As can be understood from FIG. 3, these two axial passages 48 a and 48 b open to the front surface of the flange 20 f at a line-symmetrical position rotated 15 degrees with respect to a normal line including the axis of the tool spindle 26. This open end functions as a connection port 49.
[0018]
As clearly shown in FIG. 2, in the front housing 24, two radial passages 50a and 50b formed at the same angular positions as the two axial passages 48a and 48b opened in the flange 20f are radially provided. Is formed. The outer ends of the radial passages 50a and 50b communicate with one end of the right-angle passages of the two elbow joints 51a and 51b fixed to the outer peripheral surface of the front housing 24. The other ends of the right-angle passages of the elbow joints 51a and 51b are fluid-tightly fitted to the front ends of the supply relay pipes 52a and 52b, and two connection ports on the flange 20f of the corresponding axial passages 48a and 48b. Connection pieces 53a and 53b for liquid-tightly closing 49 are fitted in a liquid-tight manner at the rear ends of the relay pipes 52a and 52b.
[0019]
On the other hand, the inner end of one of the radial passages 50a opens into the bearing inner hole 55 of the front housing 24, and the other radial passage 50b is an intermediate axial passage that extends in the axial direction at the radial intermediate portion of the front housing 24. After that, it advances inward from an intermediate position between the pair of front rolling bearings 28 a and 28 b and opens in the bearing inner hole 55. The outer rings of the pair of front rolling bearings 28 a and 28 b are regulated in the axial direction by the spacers 57 and 58 between the front cap 25 fixed to the front and rear ends of the front housing 24 by bolts and the bearing holder 56. Positioned at a predetermined interval.
[0020]
A semicircular annular groove is formed on the outer periphery of the cylindrical portion that fits into the bearing inner hole 55 of the bearing retainer 56, and this semicircular annular groove communicates with the supply of lubricating oil from the inner end of the radial passage 50a. Yes. A pair of nozzles 56a (only one of them is shown in FIG. 2) communicates with the semicircular annular groove on the front end surface of the cylindrical portion of the bearing retainer 56 and jets lubricating oil toward the annular space between the inner and outer rings of the rolling bearing 28b. Are provided at angular positions opposed to each other in the radial direction.
[0021]
Similarly, a half-circular annular groove is formed on the outer periphery of the spacer 57, and this half-circular annular groove communicates with the supply of lubricating oil from the inner end of the other radial passage 50b. At the front end of the spacer 57, a pair of nozzles 57a (only one of which is shown in FIG. 2) that are in communication with the half-circular annular groove and jet lubricant oil toward the annular space between the inner and outer rings of the rolling bearing 28a face each other in the radial direction. Is disposed at an angular position.
[0022]
On the other hand, the collection path 47 includes three elbow joints 60a to 60c fixed to the lower part of the outer periphery of the front housing 24 as shown in FIG. The central elbow joint 60b is directly below the tool main shaft 26, and the adjacent elbow joints 60a and 60c are arranged 25 degrees apart from each other. Three radial passages 61a to 61c communicating with one of the right-angle holes of the elbow joints 60a to 60c are formed in the front housing 24, and the central radial passage 61b opens directly into the inner hole of the front housing 24. To the annular sleeve between the rotor sleeve 34 and the communication hole 56 b of the bearing retainer 56.
[0023]
The radial passages 61a and 61b communicating with the elbow joints 60a and 60c are bent forward in the axial direction and extend radially inward again at positions corresponding to the spacers 57 and 58 to open to the bearing inner hole 55. doing. The spacers 57 and 58 connect these radial passages 61a and 61c to the space between the rolling bearings 28a and 28b and the front space of the bearing 28a through the respective communication holes 57b and 58b. The outer ring spacer 58 and the inner ring spacer opposite thereto are shaped to form a labyrinth seal.
[0024]
The elbow joints 60 a to 60 c are liquid-tightly fitted to the front ends of the three collection relay pipes 62 a to 62 c provided in parallel with the tool spindle 26. These relay pipes 62 a to 62 c are arranged outside the housing body 22 so as to surround the lower outer periphery of the housing body 22. On the front end face of the flange 20f of the housing body 22, connection pieces 63a to 63c having the same configuration as the connection pieces 53a and 53b described above are fixed at angular positions corresponding to the elbow joints 60a to 60c as shown in FIG. .
[0025]
These connection pieces 63a to 63c are liquid-tightly fitted to the rear ends of the relay pipes 62a to 62c, and the lubricating oil recovered through the relay pipes 62a to 62c is opened to the front surface of the flange 20f. It leads to one connection port 63 (see FIG. 1), and leads from these connection ports to three axial passages 64a to 64c formed in the housing body 22. In FIG. 1, only the passage 64b directly below the tool spindle 26 is shown. The recovery pump P <b> 2 sucks the lubricating oil from a recovery port that opens in the rear end face of the housing body 22 of these axial passages 64 a to 63 c and returns to the reservoir of the lubricating oil supply device 45.
[0026]
In FIG. 1, reference numerals 70a and 70b denote two supply passages for supplying lubricating oil to the rear rolling bearings 27a and 27b, and reference numerals 71a to 71c recover the lubricating oil supplied to the rolling bearings 27a and 27b. Three collection passages are shown. These supply passages 70a and 70b are respectively arranged at an angular phase corresponding to the relay pipes 52a and 52b and connected to the supply pump P1, whereas the recovery passages 71a to 71c are respectively connected to the relay pipes 62a to 62c. It is arranged at a corresponding angular phase and is connected to the suction pump P2.
[0027]
In FIG. 1, reference numerals 72 to 75 denote flexible pipes formed of rubber tubes or the like, and reference numeral 77 denotes an oil temperature control device that controls the temperature of the lubricating oil in the reservoir of the lubricating oil supply device 45.
Next, the operation of the embodiment configured as described above will be described.
When an activation command for the tool spindle 26 is given for the machining operation, the servo motor 30 is driven, and the tool spindle 26 integrated with a rotor (not shown) is rotated. In association with the rotation operation of the tool spindle 26, the motor M of the lubricating oil supply device 45 is rotated, and the supply pump P1 supplies the lubricating oil to the axial passages 48a and 48b and the passages 70a and 70b at a pressure of about 10 kgf / cm ² . Supply. At the same time, the suction pump P2 sucks lubricating oil from the axial passages 64a to 64c and the passages 71a to 71c.
[0028]
Lubricating oil supplied to the axial passages 48 a and 48 b is introduced into the radial passages 50 a and 50 b in the front housing 24 through the connection port 49 and the relay pipes 52 a and 52 b, and further from a pair of nozzles 57 a of the outer ring spacer 57. While being ejected to the front rolling bearing 28a, it is ejected from the pair of nozzles 56a of the bearing retainer 56 to the front rolling bearing 28b. The lubricating oil jets ejected to the bearings 28a and 28b cool and lubricate the rolling surfaces of the inner and outer rings of the bearings 28a and 28b.
[0029]
Lubricating oil supplied to the front rolling bearings 28a and 28b passes through three recovery radial passages 61a to 61c and elbow joints 60a to 60c formed in the front housing 22, and then to the recovery relay pipes 62a to 62. From there, it is returned to the reservoir by the suction pump P2 through the connection port 63 and the axial passages 64a to 64c.
[0030]
The lubricating oil that has cooled the rolling bearings 28a and 28b is warmed and introduced into the recovery relay pipes 62a to 62c in a state where the temperature has risen. Therefore, the lubricating oil passing through the supply relay pipes 52a to 52b and the lubricating oil passing through the recovery relay pipes 62a to 62c have a considerable temperature difference.
When a considerable temperature difference occurs between the upper side and the lower side of the housing main body 23, the lower side portion of the housing main body 23 is thermally expanded larger than the upper side portion from the flange 20f as a mounting reference, and as a result, the front rolling bearing The front housing 24 into which 28a and 28b are fitted is thermally deformed so that the front surface thereof is inclined upward, and the tool T mounted on the tool spindle 26 is inclined with the axis thereof facing upward. The inclination of the tool axis line due to such thermal deformation reduces the machining accuracy of a workpiece not shown.
[0031]
However, in the illustrated embodiment of the present invention, the relay pipes 62a to 62c for recovery and the relay pipes 52a and 52b for supply are arranged outside the housing body 23, and the front portion of the flange 20f of the housing body 23 is shown. The heat of the lubricating oil passing through these pipes 62a to 62c, 52a, 52b is prevented from being transmitted. For this reason, a significant temperature difference does not occur between the upper part and the lower part of the housing body 23, and the above-described problems caused by this temperature difference are eliminated.
[0032]
The heat of the recovered lubricating oil is transmitted to the rear part of the housing body 22 from the flange 20f when the lubricating oil passes through the axial passages 64a to 64c. The lower part is greatly thermally deformed rearward. However, since the housing 20 has the flange 20f as a starting point of thermal deformation, the thermal deformation of the rear portion of the flange portion 20f hardly affects the thermal deformation of the front portion.
[0033]
In particular, in the illustrated embodiment, the rear rolling bearings 27a and 27b are housed in a bearing case (not shown) that is always urged rearward. It is absorbed by a minute movement toward the rear of the case and prevents the front portion of the flange 20f from being affected.
The lubricating oil supplied to the supply passages 70a and 70b cools and lubricates the rear rolling bearings 27a and 27b, and is returned to the lubricating oil supply device 45 through the recovery passages 71a to 71c.
[0034]
FIG. 4 shows a main part of another embodiment according to the present invention. In this other embodiment, instead of the collection relay pipes 62a to 62c disposed outside the housing body 23, FIG. Collection relay pipes 162a to 162c made of a known heat insulating material are used, and these heat insulating pipes 162a to 162c are fitted into holes formed concentrically in the housing main body 22 and the front housing 24.
[0035]
Lubricating oil that has lubricated the front rolling bearings 28a and 28b passes from the radial passages 61a to 61c of the front housing 24 into the heat insulating pipes 162a to 162c through the lateral holes formed at the distal ends of the corresponding heat insulating pipes 162a to 162c. They are sucked, led from these to the axial passages 64 a to 64 c in the housing body 23, and returned to the lubricating oil supply device 45.
[0036]
In the other embodiment, the relay pipes 162a to 162c for recovery are arranged in the housing main body 23. However, the heat of the lubricating oil that passes by making the material of these pipes a heat insulating material is the housing main body 23. To prevent conduction.
Although the configuration of the relay pipe for supply in this other embodiment is omitted in the drawing, the same configuration as that of the relay pipes 162a to 162c is adopted and embedded in the housing body 23. In FIG. 4, reference numeral 163 denotes a plug fixed to the front housing 22 in order to close the opening end of the insertion hole of each of the collection relay pipes 162a to 162c.
[0037]
In each of the embodiments described above, there are two lubricating oil supply paths and three lubricating oil recovery paths, but such a configuration can supply lubricating oil evenly to the front rolling bearings 28a and 28b. This is advantageous in that the lubricating oil can be reliably recovered from the space on both sides and the middle space of the bearing. However, one supply path and one recovery path are provided, the supply path branches into two immediately before the front rolling bearings 28a and 28b, and the recovery path includes three passages in the front housing 23 and these three passages. It is good also as a structure which gathers together just before reaching a collection | recovery relay pipe.
[0038]
In the above-described embodiment, the supply-use axial passages 48a and 48b and the collection-use axial passages 64a to 64c are formed in the housing body 22, but a part of each of these axial passages is formed. You may form in the carrier 12 integral with a spindle head.
Furthermore, the structure of the relay pipe in the present invention is preferably used for a spindle head device that supports the front side and the rear side of the main shaft 26 by rolling bearings. The main shaft 26 is used as a bearing other than the rolling bearing, for example, a fluid bearing. It can also be applied as means for supplying bearing fluid to a fluid bearing in a spindle head device of the type supported by
[0039]
【The invention's effect】
As described above in detail, according to the present invention, the spindle head is fixed to the carrier at the mounting portion formed in the portion of the housing that is largely retracted in the axial direction from the first bearing that rotatably supports the front side portion of the spindle. In a spindle head device in which a supply path and a recovery path for connecting between the first bearing and the lubricating liquid supply apparatus are provided on both sides in the radial direction of the main shaft, at least one of the supply path and the recovery path, preferably the recovery path And a passage for relaying a connection port opened in the vicinity of the attachment portion and a radial passage formed in the radial direction in the housing in the vicinity of the first bearing, and heat of the lubricating liquid passing through the relay passage. Is not conducted to the housing, so that the radial direction of the portion in the axial direction from the first bearing to the mounting portion of the housing On both sides are prevented from being thermally unbalanced, as a result the difference in thermal expansion between the both sides of the radial direction of the housing can malfunction elimination on rotational accuracy and on the processing accuracy of the originating spindle.
[0040]
In particular, as in the invention of claim 2, when the relay passage is constituted by a pipe and is arranged outside the housing, a space is formed between the relay pipe and the housing. Heat conduction is reliably prevented.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional side view showing an embodiment of the present invention.
FIG. 2 is an enlarged longitudinal sectional view showing a front end portion of an embodiment of the present invention.
FIG. 3 is an enlarged front view of an embodiment of the present invention.
FIG. 4 is a partial longitudinal sectional view of another embodiment of the present invention.
[Explanation of symbols]
10 ... Column of machine tool 12 ... Carrier (Y-axis slide)
20 ... Spindle head 20f ... Flange (mounting part)
22 ... Housing 26 ... Tool spindles 28a, 28b ... Front rolling bearings 27a, 27b ... Rear rolling bearings 30 ... Servo motor 45 ... Lubricating oil supply devices 49, 63 ... ... Connection ports 51a, 51b, 60a to 60c ... Elbow joints 48a, 48b, 64a to 64c ... Axial passages 50a, 50b, 61a to 61c ... Recovery radial passages 52a, 52b, 62a ... 62c ... Relay pipe

Claims (3)

A main shaft is rotatably supported in the housing via first and second bearings at a front end side where a tool or a workpiece is detachably mounted and a rear end side separated from the front end side, and the housing is supported on the main shaft. A supply path that is fixed to the support member at a mounting portion formed on the housing at a position rearward in the axial direction from the first bearing that supports the front end side, and that supplies the lubricant from the lubricant supply means to the first bearing. And a recovery path for recovering the lubricating liquid supplied to the first bearing to the lubricating liquid supply means, in a spindle head in a machine tool provided opposite to the radial direction of the main spindle, of the supply path and the recovery path A radial passage formed radially in the housing in the vicinity of the position where the first bearing is disposed, and the radial passage. A connection port that is opened in the vicinity of the mounting portion that is spaced apart from the main shaft in the axial direction and is connected to the lubricating liquid supply means, and a passage that relays the connection port and the radial passage. A spindle head device in a machine tool, comprising: a relay passage for preventing heat of the lubricating liquid passing through the housing from being conducted to the housing. 2. The spindle head device according to claim 1, wherein the first and second bearings are rolling bearings, the spindle is supported to be rotatable around a horizontal axis, and the supply path and the recovery path each have a diameter of the spindle. The relay passages that are disposed on the upper side and the lower side that are opposed to each other in the direction and that constitute each of the supply path and the recovery path extend in the axial direction of the main shaft outside the housing, and are connected to the connection port and the diameter. A spindle head device comprising a relay pipe connected to a direction passage. 2. The spindle head device according to claim 1, wherein the first and second bearings are rolling bearings, the spindle is supported to be rotatable around a horizontal axis, and the supply path and the recovery path each have a diameter of the spindle. The relay passages that are disposed on the upper side and the lower side that are opposite to each other and that constitute each of the supply path and the recovery path extend in the axial direction of the main shaft inside the housing, and are connected to the connection port and the radial direction. A spindle head device comprising a relay pipe made of a heat insulating material connected to a passage.

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