JP4480444B2 - Machine tool spindle equipment - Google Patents

Description

  The present invention relates to a spindle device of a machine tool that facilitates replacement of a spindle such as a vertical or horizontal milling machine or a machining center, and more particularly to a spindle device of a machine tool provided with a through spindle coolant device that allows machining fluid to pass inside the spindle.

  Machine tool spindles rotate at high speed during cutting and receive large cutting resistance, bearings wear and damage, and tool clamp collets and disc springs arranged in the spindle break. There are things to do. Thus, the failure of the main shaft device not only occurs in the main shaft itself but also in the internal structure of the main shaft and the bearing. When repairing the spindle device at the site where the machine tool is used, remove the hydraulic / pneumatic piping for lubrication, cooling and cleaning, electrical wiring to the motor and limit switch, disassemble the entire spindle device, It is common to replace parts or bearings and reassemble. This repair work was extensive, required advanced expertise and skills, and took a lot of time. For this reason, a spindle device that allows a spindle and a bearing, generally called a cartridge-type spindle, to be integrally removed has been developed, and is disclosed in, for example, Patent Document 1 and the like.

On the other hand, in recent machine tools, heavy cutting is required to shorten the machining time. For this reason, the machining area between the tool cutting edge and the workpiece becomes very hot, and in order to cool this efficiently, coolant and pressurized air are circulated inside the spindle of the machine tool, and the spindle tip There is a through-spindle coolant device that supplies coolant and pressurized air from the tool mounted on the machine to the machining area. Patent Document 2 discloses such a through spindle coolant device and a rotary joint for transferring a fluid from a fixed pipeline to a rotating pipeline of the through spindle coolant device.
JP 2003-159622 A JP-A-6-241364

  However, since the rotary joint disclosed in Patent Document 2 is not premised on application to a cartridge-type spindle device, there is a problem that the spindle cannot be easily removed when it is used in a cartridge-type spindle device. That is, when the rotary joint of Patent Document 2 is simply applied to a cartridge-type main spindle device, the rotary joint is provided on the rear side of the drawbar unclamping device, and the drawbar becomes longer or supports the bearing in the middle. There is a problem that it becomes necessary to make a structure that allows the drawbar to be separated along the way when the spindle is removed.

  An object of the present invention is to provide a cartridge type spindle device having a structure that can be easily separated while providing a rotary joint for a through spindle coolant device. Yes.

To achieve the above object, according to the present invention, there is provided a spindle device of a machine tool having a spindle rotatably supported by a housing by a front bearing and a rear bearing, the housing comprising a front housing, a rear housing, A front bearing portion of the main shaft is incorporated in the front housing, the rear bearing portion of the main shaft is supported in the rear housing, and the front housing is separated from the rear housing, In the spindle device of the machine tool, the front bearing portion, the main shaft, and the rear bearing portion can be separated from the rear housing integrally with the front housing.
A draw bar extending in the main shaft along the central axis of the main shaft and clamping a tool attached to the tip of the main shaft;
A coolant passage formed through the draw bar along the central axis;
An unclamping device that has a drawbar drive piston that presses the drawbar along the central axis in the direction of the spindle end, and unclamps the tool attached to the tip of the spindle;
A second seal ring is attached to the tip of the unclamp device in a recess formed in the piston and attached to the rear end of the draw bar so that it moves along the central axis of the main shaft. A rotary joint having a coolant supply pipe provided as possible;
And a spindle device of a machine tool in which the draw bar is separated from the rear housing and the rotary joint together with the main shaft and the front housing with the first seal ring.

  According to the present invention, the unclamping means is disposed immediately after the rear end of the main shaft, and the rotary joint is positioned in the drawbar drive piston of the unclamping means. The overhang) can be shortened, and the rotary-side seal ring of the rotary joint can be configured without providing a bearing. Further, since the protrusion to the rear of the draw bar can be shortened, the main shaft including the draw bar can be shortened and can be easily separated from the rear housing, and the main shaft can be easily and quickly replaced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, although embodiment of this invention is described taking a horizontal machining center as an example, this invention is not limited to this, It is applicable also to a vertical machining center.

  In FIG. 1, a spindle head 11 of a horizontal machining center moves up and down along a Y-axis guide rail 13 of a column (not shown) that is erected and fixed on a bed (not shown) that forms a base. Inside the spindle head 11, a spindle 15 that is rotationally driven by a built-in motor is rotatably supported by front bearings 17a and 17b and rear bearings 19a and 19b. A tool holder 21 to which various tools (not shown) are attached is replaceably mounted in the tapered hole 15a at the tip of the main shaft 15.

  The housing of the spindle head 11 is composed of a front housing 23 and a rear housing 25, both of which are integrally fastened by a plurality of bolts 27. In the front housing 23, two front bearings 17a and 17b for rotating and supporting the front portion of the main shaft 15 are provided. The inner ring of the left front bearing 17a is in contact with the shoulder of the main shaft 15, and the inner ring of the right front bearing 17b is fixed to the main shaft 15 by the nut 29 with the inner ring collar interposed therebetween. The outer ring of the right front bearing 17b contacts the shoulder of the front housing 23, and the outer ring of the left front bearing 17a is fixed by the bearing retainer 31 with the outer ring collar interposed therebetween.

  A bearing case 33 is fitted in a hole 35 formed in the rear housing 25, and two rear bearings 19 a and 19 b that rotatably support the rear portion of the main shaft 15 are provided in the bearing case 33. . The inner ring of the left rear bearing 19 a abuts against the shoulder of the main shaft 15, and the inner ring of the right rear bearing 19 b is fixed to the main shaft 15 by the nut 37 across the inner ring collar. The outer ring of the left rear bearing 19a abuts against the shoulder of the bearing case 33, and the outer ring of the right rear bearing 19b is fixed by the bearing retainer 39 with the outer ring collar interposed therebetween.

  A built-in motor stator 41 is provided in the rear housing 25, and a rotor 43 is provided on the main shaft 15 side via a minute gap in the radial direction. The rotor 43 is fitted on the shrink fit sleeve 45, and the shrink fit sleeve 45 is fit on the main shaft 15.

  The tool holder 21 is inserted into the tapered hole 15 a at the tip of the main shaft 15, and a pull stud 47 provided at the rear portion of the tool holder 21 is gripped by the collet 49. The collet 49 can be moved back and forth in the axial direction by a draw bar 51. A large number of disc springs 55 are provided on the inner peripheral surface of the main shaft 15 via a sleeve 53, and the right side of the disc spring 55 is regulated by a nut 57 screwed to the rear end of the draw bar 51 with a collar interposed therebetween. The disc spring 55 applies a backward elastic biasing force to the draw bar 51, and the collet 49 closely contacts and clamps the taper shank of the tool holder 21 to the taper hole 15 a of the main shaft 15.

  A draw bar drive means for pressing and driving the draw bar 51 in the direction of the distal end of the main shaft 15 is provided at the rear part of the rear housing 25, and the draw bar drive means is a draw bar drive attached to the rear end of the rear housing 25. A cylinder 61 and a draw bar drive piston 63 that reciprocates along the central axis O by hydraulic pressure in the draw bar drive cylinder 61 are provided. Here, referring to FIG. 2, which is an enlarged cross-sectional view of the rear end portion of the main shaft 15, the draw bar drive piston 63 protrudes in a boss shape on the front end surface (right end side in FIG. 2) facing the rear end of the main shaft 15. A contact portion 63a, a recess 63b formed so as to open rearward in the draw bar drive piston 63, and a through-hole 63c extending from the contact portion 63a to the recess 63b are formed. The drawbar drive cylinder 61 is formed with first and second hydraulic ports 65 and 67.

  On the other hand, the draw bar 51 is extended from the rear end portion along the central axis O in the rearward direction so as to be slidably fitted into the through hole 63c of the draw bar drive piston 63, and the base of the extension portion 51b. It has a contact shoulder portion 51a formed so as to be able to contact and separate from the contact portion 63a at the end portion. As described above, the draw bar 51 is urged rearward by the force of the disc spring 55 in order to clamp the tool holder 21 mounted in the tapered hole 15a of the main shaft 15. When pressure oil is supplied to the first hydraulic port 65 of the draw bar drive cylinder 61, the draw bar drive piston 63 moves forward, and its abutment portion 63a abuts against the abutment shoulder portion 51a of the draw bar 51, causing the draw bar 51 to move. Press forward. As a result, the collet 49 moves forward via the draw bar 51. Then, the tip of the collet 49 is positioned at a location where the inner diameter of the sleeve 53 is large, the engagement between the collet 49 and the pull stud 47 is released, and the tool holder 21 is unclamped.

  Further, referring to FIG. 2, the draw bar 51 has a seal ring 69 attached to the rear end thereof, and a coolant passage 51 c formed along the central axis O thereof. As will be described later, coolant is supplied to the coolant passage 51c from the rotary joint 100 incorporated in the draw bar drive piston 63. This coolant is supplied between the cutting edge (not shown) of the tool T and the workpiece (not shown) from the coolant passage 51c via the tool holder 21 and the passages 21a and Ta formed in the tool T. Is ejected to the machining area.

  The rotary joint 100 includes a cylinder 101 disposed in a recess 63 b of the draw bar drive piston 63, and a piston 103 provided in the cylinder 101 so as to be capable of reciprocating along a central axis O. The piston 103 is formed in a bowl shape integrally with the coolant supply pipe 105, and the piston 103 divides the internal space of the cylinder 101 into a pneumatic chamber 107 and a spring chamber 109. A coil spring 115 is provided in the spring chamber 109 to urge the piston 103 and the coolant supply pipe 105 backward. The cylinder 101 is formed with an air pressure port 101a for supplying compressed air to the air pressure chamber 107. The air pressure port 101a is connected to an external air pressure source (not shown). Compressed air can be supplied from the source into the pneumatic chamber 107, and the air in the pneumatic chamber 107 can be discharged.

  The coolant supply pipe 105 has a seal ring 113 attached to the tip thereof so as to face the seal ring 69 of the draw bar 51, a coolant passage 105 a formed along the central axis O, and a rear end of the coolant supply pipe 105. In FIG. 2, there are a plurality of radial passages 105b formed in the radial direction so as to open to the coolant passage 105a at adjacent portions, and a cutoff valve 105c formed at the rear end of the coolant supply pipe 105 in FIG. is doing. A coupling member 111 for connecting a hose (not shown) for connecting the coolant supply pipe 105 to an external coolant supply device (not shown) is connected to the rear end surface of the cylinder 101. The joint member 111 includes an internal space 111a that houses a rear end portion including the radial passage 105b of the coolant supply pipe 105, and an inlet port 111b that extends from the rear end of the joint member 111 to the internal space 111a and is connected to one end of the hose. And is formed in a substantially cylindrical shape. The inner diameter of the inlet port 111b is smaller than the inner diameter of the inner space 111a, and a valve seat 111c on which the shutoff valve 105c of the coolant supply pipe 105 is seated is formed between the inlet port 111b and the inner space 111a.

Hereinafter, the operation of the present embodiment will be described.
The hydraulic oil is supplied to the first hydraulic port 65 from an external hydraulic source (not shown), and the hydraulic oil is recovered from the second hydraulic port 67 to the hydraulic source, so that the drawbar drive piston 63 is shown in FIG. 2 to move left. As a result, the contact portion 63a of the draw bar drive piston 63 contacts the contact shoulder portion 51a of the draw bar 51, and the draw bar 51 advances to the left in FIGS. Thus, the tool T is unclamped together with the tool holder 21 mounted in the tapered hole 15a at the tip of the main shaft 15. On the contrary, by supplying the hydraulic oil to the second hydraulic port 67 and collecting the hydraulic oil from the first hydraulic port 65, the draw bar drive piston 63 moves backward, and the draw bar 51 is moved backward by the biasing force of the disc spring 55. Move to the right (in FIGS. 1 and 2). As a result, the collet 49 at the tip of the draw bar 51 grips the pull stud 47 of the tool holder 21, pulls the tool holder 21 into the tapered hole 15 a, and the tool holder 21 and the tool T are clamped to the tip of the main shaft 15.

  Next, prior to the start of processing by the tool T, compressed air is supplied to the pneumatic port 101a of the cylinder 101 of the rotary joint 100, and the piston 103 and the coolant supply pipe 105 resist the biasing force of the coil spring 115 as shown in FIG. The coolant supply pipe 105 is abutted against the seal ring 69 attached to the rear end of the draw bar 51 in the seal ring 113 attached to the tip of the coolant supply pipe 105, and the coolant supply pipe of the rotary joint 100 is 105 coolant passages 105 a communicate with the coolant passage 51 c of the draw bar 51. At the same time, the shutoff valve 105c at the rear end of the coolant supply pipe 105 is separated from the valve seat 111c, and coolant is supplied via a hose (not shown) connected to the inlet port 111b of the joint member 111 and the radial passage 105b. The coolant passage 105a of the pipe 105 communicates with an external coolant supply source. Accordingly, the coolant supplied from the coolant supply source passes through the hose, the inlet port 111b, the radius passage 105b, the coolant passage 105a, the coolant passage 51c, the tool holder 21 and the passages 21a and Ta formed in the tool T. The coolant is ejected to the machining area between the cutting edge of the tool T and the workpiece. The coolant leaking from between the two seal rings 113 and 69 slightly flows into the rear housing 25 from the gap between the extended portion 51b of the draw bar 51 and the through hole 63c of the draw bar drive piston 63. It can be recovered by appropriately forming the drain 25 a in the housing 25.

  On the other hand, when the front housing 23 loosens the bolts 27 and pulls the front housing 23 forward, the front housing 23 is separated from the rear housing 25 in an integrated state with the main shaft 15 via the front bearings 17a and 17b. The At this time, the main shaft 15 is attached with a built-in main shaft 15 including a rotor 43, a bearing case 33 incorporating the rear bearing 19, and a tool holder 21, a collet 49, a draw bar 51, a disc spring 55, and the like. A portion that can be taken out integrally with the front housing 23 is referred to as a front housing unit. Further, at this time, the draw bar 51 is pulled out together with the main shaft 15 together with the seal ring 69, and the draw bar 51 is separated from the coolant supply pipe 105 at this portion. That is, the coolant supply path consisting of the hose, the inlet port 111b, the radius passage 105b, the coolant passage 105a, the coolant passage 51c, the passage 21a of the tool holder 21 and the passage Ta of the tool T from the coolant supply source to the machining area is as follows. The seal ring of the draw bar 51 and the seal ring 113 of the coolant supply pipe 105 are separated.

  In this embodiment, the case where the rotary joint 100 is fixed to the recess 63b of the piston 63 is shown. However, the rotary joint 100 is supported by a bracket from the cylinder 61, and the piston 63 is placed in the recess 63b of the piston 63. It may be a structure that is positioned independently.

  In this embodiment, the structure in which the front housing unit of the horizontal machining center is manually pulled out from the rear housing 25 has been described as an example. However, the present invention is not limited to this and is also applicable to a spindle device of a vertical machining center. Is possible. That is, the flange equivalent member of the front housing of the vertical spindle device is fixed on the table via a jig, and the front housing unit is moved to the rear in the same manner as the horizontal machining center using the vertical Z-axis feed operation. Can be extracted from the housing. The present invention can be applied not only to a machining center and an NC machine tool but also to a general-purpose machine tool that manually performs a feeding operation.

It is sectional drawing of the main axis | shaft apparatus of the machine tool of this invention. It is an expanded sectional view of the rear-end part of a main axis | shaft, and is a figure which shows the rotary joint by preferable embodiment of this invention.

Explanation of symbols

11 spindle head 15 spindle 17a front bearing 17b front bearing 19a rear bearing 19b rear bearing 21 tool holder 23 front housing 25 rear housing 47 pull stud 49 collet 51 draw bar 55 disc spring 61 draw bar drive cylinder 63 draw bar drive piston 69 seal ring 100 Rotary joint 101 Cylinder 103 Piston 105 Coolant supply pipe 113 Seal ring

Claims (1)

A spindle device of a machine tool having a spindle rotatably supported by a front bearing and a rear bearing on a housing, wherein the housing is detachably fastened to the front housing and the rear housing, and the spindle is attached to the front housing. When the front bearing portion is incorporated, the rear housing supports the rear bearing portion of the main shaft, and the front housing is separated from the rear housing, the front bearing portion, the main shaft, and the rear bearing portion are in front of the front housing portion. In the spindle device of the machine tool that can be separated from the rear housing integrally with the part housing,
A draw bar extending in the main shaft along the central axis of the main shaft and clamping a tool attached to the tip of the main shaft;
A coolant passage formed through the draw bar along the central axis;
An unclamping device that has a drawbar drive piston that presses the drawbar along the central axis in the direction of the spindle end, and unclamps the tool attached to the tip of the spindle;
A second seal ring is attached to the tip of the unclamp device in a recess formed in the piston, and is attached to and separated from the first seal ring attached to the rear end of the draw bar, along the central axis of the main shaft. A rotary joint having a coolant supply pipe provided movably;
A spindle device for a machine tool, wherein the draw bar is separated from the rear housing and the rotary joint together with the main shaft and the front housing together with the first seal ring.

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