JPH03117501A - Special purpose machine for shaft-like workpiece - Google Patents

Abstract

PURPOSE:To perform machining of a center bore at ends of a workpiece, both end faces and the outside circumferential surface thereof automatically by means of center drills and center spindles which are respectively movable in the axial direction inside a center bore by providing hollow main spindles on the opposing two headstocks. CONSTITUTION:When a workpiece W clamped by movable chucks 21 is fixed at a specified position between both headstocks 11,12, the headstocks 11,12 come close to both ends of the workpiece W and center bore machining is performed by center drills 71 which are clamped by tool chucks of main spindles. In company with this, end face machining is performed by facing tools 70 arranged on work chucks on the front end part outer periphery of each main spindle, and next center spindles, replacing the center drills 71, are clamped inside the hollow main spindles to hold the workpiece W. When the workpiece W is clamped by work chuck jaws 52, the movable chucks 21 are released and the workpiece W is rotated for machining at the outside circumferential surface by a machining tool therefor. Machining of the center bore, the end faces and the outside circular surface of the workpiece can be thus automatically performed by a single machine.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a machine tool specifically designed for shaft objects, which is suitable for turning relatively long shaft objects such as camshafts.

Conventional technology Conventionally, when turning a camshaft, a method has been adopted in which a centering machine is used to first drill a center hole and end faces at both ends of the workpiece, and then a lathe is used to machine the outer diameter of the workpiece. . This machining method requires two types of machine tools, namely a centering machine and a lathe, and furthermore, the setup must be changed every time the type of workpiece (dimensions, shape, etc.) changes.

Problems to be Solved by the Invention The conventional processing method described above is convenient for mass production because it can increase production efficiency by processing each step in 1111 L minutes and using a dedicated machine. However, in the case of high-variety, low-volume production or in the case of heavy use of prototype parts, there was a problem in that equipment costs were too high.

The present invention was made to solve these problems in the conventional machining method, and is capable of automatically processing everything from a black-skinned workpiece to completion of turning with just one machine, and Specially designed for shaft objects that can be easily adapted to different types of workpieces by simply changing the NC program.
■The purpose is to provide two machineries.

Means for Solving the Problems In order to achieve the above object, the machine tools for shaft objects of the present invention are arranged facing each other on the same axis in the Z-axis direction, and are arranged so as to be able to approach and separate from each other. two main spindles consisting of two main spindles, two main spindles each of which is rotatably provided on each of the two main spindles and is arranged opposite to each other; A chuck, a workpiece chuck provided on the outer periphery of the front end of both the spindles, an end face bite fixed to the front end of the workpiece chuck, and individually moved in the axial direction into the hollow holes of both the spindles. A center drill and a center shaft are housed in the center drill, and a motor provided at the rear of the two main shafts allows the center drill and the center shaft to be individually reciprocated in the axial direction and replaced with the tool chuck. a moving tool changer; a movable chuck that is movably provided between the two headstocks and supports and clamps the work coaxially with the two main spindles; and a movable chuck that is movable in the Z-axis direction and the X-axis direction. It is characterized by being equipped with a turret.

It is preferable that a plurality of the center drills and center shafts are housed in the hollow hole of the shaft so that they can be easily and quickly replaced when worn or broken. In addition, center drills and center shafts of different shapes are stored so that the center drill and center shaft can be appropriately selected according to the workpiece.

The workpiece is clamped by a movable chuck and fixedly supported at a predetermined position between the two headstocks.

Both headstocks approach both ends of the workpiece, and a center drill clamped to the tool chuck of the main spindle drills a center hole in the workpiece, and an end face tool machine drills the end face. next,
Both headstocks are separated from the workpiece, and the center shaft is clamped to the tool chuck instead of the center drill. When both headstocks approach the workpiece again and support the workpiece with both center shafts,
The moving chuck unclamps and moves away from the workpiece. Next, the workpiece chuck installed on one of the spindles operates to clamp one end of the workpiece, and at the same time, the spindle rotates to rotate the workpiece, turning the outer diameter part way from the other end of the workpiece that is not clamped. do. Next, after the rotation of the workpiece is stopped and the clamping of the workpiece by the workpiece clamp is released, the other workpiece clamp is activated to clamp the other end of the workpiece that has been subjected to the outer diameter processing. After that, the main shaft on the clamped side rotates to rotate the workpiece, and the outer diameter part of the workpiece that could not be machined in the previous process is turned, and both center holes, both end faces, and all outer diameters are machined. Complete.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a plan view schematically showing a machine tool exclusively for shaft objects according to the present invention.

10 is the bed, 11 and 12 are Z on the bed 10
A first headstock and a second headstock are arranged opposite to each other in the axial direction, and are provided so as to be movable back and forth in the Z-axis direction along the same axis by servo motors 13 and 14, respectively. Ill be approached and separated.

Reference numeral 15 denotes a tool rest, which is provided so as to be able to reciprocate along a guide rail 16 in parallel with the Z axis, and is also provided along a guide rail 17.
It is provided so that it can freely move back and forth parallel to the X-axis along
A turret 18 is provided on the tool rest 15 so as to be indexable and rotatable about a rotation shaft 19 disposed parallel to the Z-axis.

A turning tool 20 such as a cutting tool is mounted on each mounting surface of the turret 18.
The chuck 21 to which is attached is a movable chuck placed between the two main shafts No. 11 and No. 12, and is movable in parallel to the Z-axis and the X-axis. In order to support a workpiece W having a relatively long shaft, two movable chucks 21 are arranged at appropriate intervals in the two-axis direction as shown in the figure. It is arranged as follows.

As shown in FIG. 2, the movable chuck 21 includes a fixed claw 23 fixed to the chuck body 22, and two movable claws 24, 24 pivotally attached to the chuck body 22 via a pin 25. Both movable claws 24,24 are interlocked and connected to a piston rod 27 of a hydraulic cylinder 26 incorporated in the chuck body 22, and are operated by the hydraulic cylinder 26 to the open/close position.

Since both headstocks 11 and 12 have the same internal structure, one of the headstocks 11 will be explained with reference to FIGS. 3 and 4.

Reference numeral 31 denotes a main shaft, which is formed by a hollow shaft having a hollow hole 32 penetrating the entire length. The main shaft 31 has a bearing 33
The rotor 3 of a drive motor 35 is rotatably supported on the headstock 11 via
6 is externally fitted and fixed, and is integrated with the drive motor 35. A stator 37 of the drive motor 35 is fixed to the headstock 11.

A flange portion 38 is connected to the front end of the main shaft 31, and a tool chuck 41 (described later) is attached to the flange portion 38 using a cylindrical body 39 and a housing 4 of a work chuck 51 (described later).
0 is fixed concentrically with the main shaft 31.

The tool chuck 41 is a collet chuck, in which a collet 42 is fitted into the front end opening of a cylindrical body 39, and a cylindrical clamp piston 43, which is slidably fitted onto the collet 42, is fitted into a cylinder 44. The collet 42 is clamped by urging the main shaft 31 inwardly by a disc spring 45.
In addition, the main shaft 31 and the attachment push the clamp piston 43 outward against the main shaft 31 against the disc spring 45 by pressure oil supplied through the pressure oil supply path 46 arranged in the cylinder 39 to unclamp the collet 42. It looks like this. Pressure oil is supplied to the pressure oil supply path 46 via the rotary hydraulic joint 47.

The workpiece chuck 51 is a three-jaw chuck equipped with three chuck jaws 52 (see FIG. 4).

The three chuck claws 52 are attached to the front cover 4 of the housing 40.
They are installed in a radial arrangement on the front surface of 0a. Each chuck claw 52 has a support shaft 53 fixedly protruding from the rear side.
The support shaft 53 is connected to the front cover 40a via a spherical bearing 54.
is supported for axial sliding and tilting. An operating arm 55 is fixed to the rear end of the support shaft 53.

On the other hand, the housing 40 is provided with three air cylinders 56 corresponding to each chuck claw 52. A piston rod 58 having an inclined cutout 59 at its tip is connected to the piston 57 of each air cylinder 56.
are connected via bolts 60. The bolt 60 is inserted into a hole 61 provided in the actuating arm 55 and fixed to the τ rod 58, so that the actuating arm 55 is connected to the piston rod 5.
8 to 1-1 is connected to the tilting iiJ function. stop,
Then, the device 1. By pressing a steel ball 63 (not shown, which is biased to protrude by a leaf spring) against the inclined cam surface 59.
Therefore, the operating arm 55 is always tiltably connected to the screw rod 58 without play.

The piston 57 is pushed toward the clamp side by the pressurized air supplied through the air supply path 64, and the piston rod 58 pushes the support shaft 53 forward via the actuation arm 55 to bring it out, and the inclined cam surface 59 causes the actuation arm to 55 and support shaft 5
By tilting the distal end side of 3 downward, the chuck claw 52 is operated to the clamping position shown by the imaginary line in FIG.

Further, the piston 57 is pushed toward the unclamping side by pressurized air supplied through the air supply path 65. 1.
Then, the chuck claw 52 returns to the unclamping position shown by the solid line in FIG. Note that the pressurized air is supplied via a supply ring 66.
The air is supplied to 7τ air supply paths 64 and 65.

70 is an end bite, fixed to the front of the front cover 4Oa 1
．． installed.

71 is a center drill, 72 is a center shaft, and 73 is a tool holder, which individually reciprocates the center drill 71 and center shaft 72 housed in the hollow hole 32 of the main shaft 31 in the axial direction, and attaches them to the tool chuck 41. It is the main body of the automatic tool changer that changes the difference L2. - The tool holder 73 has a hollow hole 32
It is fixedly supported by the rear cover 11a of the headstock 11 via a flange portion 74 that is connected to the rear end.

The T-holder 73 has a plurality of guide holes 7 extending parallel to the axis.
A tool holding portion 76 is formed at the front end opening portion of each guide hole 75, and a step portion 77 and a catch 11 of a pullback spring 80, which will be described later, is provided at the intermediate portion.

78 is an operating rod a17 slidably inserted into each guide hole 75;
The locking step 7 of the flange 79 and the guide hole 75 is connected to the rear end.
7 is biased toward the rear standby position by a pullback spring 80 interposed between the main body and the main body 7.

81 is a cylinder device for pushing out tools, and the rear cover 11.
The attachment connected to a is fixed to the tube 82. The cylinder device 81 is equipped with a plurality of air cylinders 83 corresponding to a plurality of operating rods 78, and when each air cylinder 83 is operated, a suppressing piece 85 attached to the tip of its piston rod 84 is moved behind each operating rod 78. The actuating rod 78 is brought into contact with the end flange portion 79 and is pushed out against the pullback spring 80 toward the - tool holding portion 76 side of the guide hole 75 .

A tool connecting fitting 86 is connected to the front end of each operating rod 78 via a flexible connecting wire 87.
center drill 71 or center shaft 7 via bearing 88
2 is rotatably held. When the operating rod 78 is in the retracted position, the connecting wire 87 is pulled into the guide hole 75, the tool connecting fitting 86 is fitted into the tool holding part 76, and the center drill 71 or center shaft 72 is housed in a predetermined position. Retained. Furthermore, when the operating rod 78 is in the forward position, the center drill 71 or the center shaft 72 is individually pushed out via the connecting wire 87, guided to the collet guide portion 42a of the tool chuck 41, and unclamped. The collet 42 is inserted into the collet 42 in the state shown in FIG. Clamped in an upright position.

A plurality of center drills 71 and center drills 72 are housed and held in a tool holder 73 so that they can be replaced immediately when worn or broken. Furthermore, it is desirable to accommodate the center drill 71 and center shaft 72 of different shapes so that they can be replaced as appropriate depending on the workpiece.

Furthermore, the center drill 71 and the center shaft 72 are connected to the collet 4.
2, the cutting edge of the end face bit 70 comes close to the protruding tip portion, so a notch type one is used as shown in the figure.

Next, the processing sequence using the dedicated machine tool having the above configuration will be explained with reference to FIGS. 5 to 9.

First, a black leather workpiece W is clamped by two movable chucks 21.21 between the two headstocks 11 and 12, and is fixed and supported coaxially with the two main shafts 31.31. At this time, the center drill 71 is clamped to the tool chuck 41 of the main shaft 31 (see FIG. 5).

Next, both main shafts 31 and 31 rotate, respectively rotating the center drill 71 via the tool chuck 41. In this state, both headstocks 11 and 12 approach both end surfaces of the workpiece W, and a center hole 91 is machined by the center drill 71 (see FIG. 6). At the same time, the end tool 7 is fixed to the front cover 40a and rotates together with the work chuck 51.
Process the end face using 0 to finish the workpiece W to a predetermined length (
(See Figure 7).

Next, both headstocks 11.12 are separated from the workpiece W. Then, in a state where the rotation of both main shafts 31 and 31 is stopped and the tool chuck 41 is unclamped, 1. The tool extrusion cylinder device 81 of the automatic tool changer operates as described above to exchange the center drill 71 and the center shaft 72.

The replaced center shaft 72 is clamped by the tool chuck 41.

In this state, both headstocks 11.12 approach both ends of the workpiece W again, and the workpiece W is supported by both center shafts 72.72.

At this time, since the center shaft 72 is longer than the center drill 71, the end cutting tool 70 does not hit the workpiece W. When the work W is supported by both center shafts 72, 72 in this manner, the moving chucks 21, 21 unclamp the work W and move away from the work W (see FIG. 8). Next, the first
The workpiece chuck 51 of the headstock 11 operates as described above, and the three chuck claws 52 project forward while tilting to clamp one end of the workpiece W (the left end in the illustrated example). When the main shaft 31 of the first headstock 11 rotates in this state,
Since the workpiece W rotates via the workpiece chuck 51 that is linked to this, the outer diameter of the workpiece is turned halfway from the other end of the workpiece that is not clamped using the outer diameter cutting tool 20 attached to the tool post 15. (See Figure 8).

Next, after stopping the rotation of the workpiece W and releasing the clamping of the workpiece W by the workpiece chuck 51 on the first headstock 11 side, the workpiece chuck 51 on the second headstock 12 side
is activated, and the three chuck jaws 52 clamp the end of the workpiece whose outer diameter has been machined. In this state, the main shaft 31 of the second headstock 12 rotates, and the workpiece W rotates via the workpiece chuck 51 interlocked with this, so the outer diameter tool 20
The outer diameter portion of the workpiece W that was not machined in the previous process is turned (see FIG. 9).

With the above machining order, both center hole machining, both end face machining, and all outer diameter machining of the workpiece W are completed.

Note that the series of processing steps described above can be easily fully automated by NC control. Furthermore, it is possible to easily handle workpieces with different shapes and dimensions simply by changing the NC program.

Effects of the Invention Since the present invention has the above configuration, it is possible to automate double center hole machining, double end face machining, and all outer diameter machining of shaft workpieces with one machine, and it can be used for a wide variety of low-volume production products and prototype parts. Ideal for processing.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a machine tool exclusively for shaft objects according to the present invention;
Fig. 2 is a partially cutaway side view of the movable chuck, Fig. 3 is a longitudinal sectional front view of the main part of the headstock, Fig. 4 is a four end view, and Figs. 5 to 9 are explanatory diagrams showing the processing process order. It is. 5... Turret 1... Main spindle 1... Tool chuck... Work chuck 11.12... Headstock 21... Moving chuck 32... Hollow hole 42... Collet 52... ... Chuck jaw 71 ... Center drill 72 ... Center shaft 73 ...
・Tool holder 78...operating rod 80...pullback 17
spring

Claims (3)

[Claims] (1) Two headstocks arranged facing each other on the same axis in the Z-axis direction and provided so as to be able to approach and separate from each other; two main spindles consisting of hollow shafts arranged as follows; a tool chuck provided at the front end openings of both the main spindles; a workpiece chuck provided on the outer periphery of the front end of both the main spindles; and the workpiece chuck. an end face bit fixed to the front end of the main shaft; a center drill and a center shaft individually movable in the axial direction accommodated in the hollow holes of the two main shafts; an automatic tool changer configured to individually reciprocate the drill and the center shaft in the axial direction and replace the tool chuck with the tool chuck; A machine tool exclusively for shaft objects, comprising: a movable chuck that coaxially supports and clamps the tool; and a tool rest that is movable in the Z-axis direction and the X-axis direction. (2) The automatic tool changer is provided with a tool holder that is fitted into a hollow hole of the spindle and whose rear end is fixedly supported by the headstock, and that penetrates the tool holder in the axial direction. a plurality of guide holes; an operating rod inserted into the guide hole so as to be reciprocally movable; and a tool connecting fitting connected to the front end of the operating rod via a connecting wire to rotatably hold the center drill or center shaft. a spring means for pulling back the operating rod to a predetermined retracted position; and a pushing device for advancing the operating rod against the spring means and moving the center drill or center shaft to a clamping position of the tool chuck. A machine tool exclusively for shaft objects according to claim (1), comprising: (3) Claim (1) wherein a plurality of the center drills and a plurality of center shafts are each accommodated in the hollow hole of the main shaft.
) or a machine tool exclusively for shaft objects described in (2).