JPH11114703A - Tailstock device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tail stock device, which is able to detect the (any) position of both a tailstock and a tailstock spindle on a bed in order to control the position with high accuracy. SOLUTION: A tailstock device for a machine tool is provided with a tailstock 21, which is mounted on a bed 1 of a machine tool and which can freely move in a direction to part from and come into contact with a main spindle, a tailstock spindle 22, which is supported by the tail stock 21 so that it can freely advance to and retreat/ from the main spindle in order to come into pressure contact with a work gripped by the main spindle, a tailstock driving means, which moves the tailstock 21 in the direction in which the tialstock 21 parts from or approaches (the main spindle), a tailstock spindle driving means 31, which moves the tailstock spindle 22 in the advancing and retreating direction tailstock detecting means 23, 24, 36, which detect any position of the tailstock 21 on the bed 1, tailstock spindle detecting means 23, 25, 37, which detect any position of the tailstock spindle on the bed 1, and a controlling means 38, which controls the action of both tailstock driving means and tailstock spindle driving means 31, based on the detection data from both tailstock detecting means 23, 24, 36 and tailstock spindle detecting means 23, 25, 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tailstock used for a machine tool such as a lathe and a cylindrical grinder.

[0002]

2. Description of the Related Art For example, when turning a workpiece, such as a bar material or a shaft workpiece, which cannot be gripped with high accuracy by a spindle chuck, a tailstock is used. FIG. 3 shows an example in which the tailstock is mounted on a lathe.

In the figure, reference numeral 1 denotes a bed, 2 denotes a headstock, and 3 denotes a spindle chuck. Reference numeral 4 denotes a carriage, 5 denotes a traverse table, and 6 denotes a tool post. Since these are known lathe configurations, detailed description thereof will be omitted.

Reference numeral 8 denotes a tailstock provided on the bed 1, in a direction in which the tailstock is separated from and brought into contact with the spindle chuck 3, that is,
A rack (not shown) attached to the bed 1, a pinion (not shown) built in the tailstock 8 and meshing with the rack, which is movable in the directions indicated by arrows BC. The motor 8 is driven in a direction indicated by an arrow B-C by a driving means which is built in and comprises a driving motor (not shown) for rotating the pinion. Further, the tailstock 8 is provided with a clamp device (not shown) for fixing itself to the bed 1.

Reference numeral 9 denotes a tailstock shaft supported by the tailstock 8, which is driven by a hydraulic mechanism (not shown) so as to be able to advance and retreat with respect to the spindle chuck 3. Reference numeral 10 denotes a cover metal belt, which prevents chips from entering the bed 1.

In recent years, in which automatic unmanned operation has been promoted, the work is often attached to and detached from the spindle chuck 3 using an automatic device such as a loading device. It is necessary to retract the table 8 to a position where it does not interfere with the loading device. That is, when loading and unloading a workpiece by the loading device, first, the clamp device (not shown) is operated to bring the tailstock 8 into an unclamped state with respect to the bed 1 and then the drive motor (not shown). ) To retract the tailstock 8 to the right end of the bed 1 (in a direction away from the spindle chuck 3), and then complete the attachment / detachment of the work to the spindle chuck 3 by the loading device.
After retracting the loading device out of the machine, the drive motor (not shown) is driven again to advance the tailstock 8 toward the spindle chuck 3, and then the clamp device (not shown) is operated again. At least after the tailstock 8 has been clamped to the bed 1, the hydraulic mechanism (not shown)
Is driven to advance the tailstock shaft 9 toward the spindle chuck 3, and the tip of the tailstock shaft 9 supports the work.

Conventionally, the forward end position and the backward end position of the tailstock 8 are detected by a detecting means such as a limit switch so that the tailstock device can be automatically operated. The operation of the drive motor (not shown) and the hydraulic mechanism (not shown) was controlled based on this detection signal.

As shown in FIG. 3, for example, the detecting means includes a limit switch 11 for confirming a retreat end and a limit switch 12 for confirming a forward end provided on the front surface of the tailstock 8.
And a dog 14 for confirming a retreat end and a dog 15 for confirming a forward end attached to the attachment plate 13 on the front surface of the bed 1. When the tailstock 8 is advanced, after the limit switch 12 hits the dog 15 and detects this,
When stopping the drive motor (not shown) and retreating the tailstock 8, the limit switch 11 hits the dog 14 and detects this, and then stops the drive motor (not shown).

The positions of the dog 14 for confirming the backward end and the dog 15 for confirming the forward end are indicated by arrows B on the mounting plate 13.
It can be adjusted in the -C direction, and its position can be adjusted according to the type of work to be processed.

However, the limit switches 11, 1
In the control of the tailstock using the two, the detection positions of the limit switches 11 and 12 are wide, and thus the detection positions vary, so that high-precision control is not possible. There is a problem that the position adjustment must be performed for the 15 positions, and the operation is complicated, and in practice, efficient unmanned automatic operation cannot be performed.

Japanese Patent Application Laid-Open Nos. Hei 7-24605 and Hei 8-71805 disclose tailstocks that can detect an arbitrary position of a tailstock shaft and control the position thereof with high accuracy. Have been.

However, in each of the tailstocks disclosed in JP-A-7-24605 and JP-A-8-71805, the tailstock is fixed on the bed, and only the tailstock shaft is stroked. Because it supports
It is unsuitable for an automatic driving machine using a loading device as described above. Originally, the tailstock shaft is for supporting a workpiece whose grip is unstable and stabilizing its rotation state. For this reason, it is preferable that the tailstock shaft protrude from the tailstock as short as possible. Therefore, even in the automatic driving machine using the loading device, the tailstock is retracted and retracted together with the tailstock at the time of loading, rather than the above-described method in which only the tailstock is stroked during loading and retracted during loading. It is more preferable that after the push table is advanced to a predetermined position, the tailstock shaft is advanced by a minimum necessary amount to support the work.

On the other hand, even if the tailstock disclosed in JP-A-7-24605 and JP-A-8-71805 is applied to a machine in which the tailstock is moved as it is, Since the position of the tailstock on the bed is moved as needed by moving, if the position of the tailstock is unknown, after all, the position of the tailstock on the bed cannot be detected, and Interference with the tailstock and tailstock shaft during loading of the loading device cannot be effectively prevented.
In this case, regarding the movement of the tailstock, as described above,
The forward end and the backward end can be detected by a detecting means such as a limit switch. However, as described above, high-precision control cannot be performed, or the position of the dog is adjusted each time the shape of the workpiece to be processed is different. The question of what to do still remains.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to detect arbitrary positions of a tailstock and a tailstock on a bed and control them with high accuracy. The purpose of the present invention is to provide a tailstock that can be used.

[0015]

Means for Solving the Problems and the Effects The invention according to claim 1 of the present invention for achieving the above object is provided on a bed of a machine tool, and is movable in a direction of coming and going with respect to a main shaft. A tailstock, which is supported by the tailstock so as to be able to advance and retreat with respect to the spindle, and which is advanced toward the spindle side and pressed against a work gripped by the spindle, the tailstock; and Tailstock drive means for moving the tailstock in the separation / contact direction, and tailstock shaft drive means for moving the tailstock in the advance / retreat direction;
Tailstock detecting means for detecting an arbitrary position of the tailstock on the bed, tailstock detecting means for detecting an arbitrary position of the tailstock on the bed, and the tailstock detecting means And control means for controlling the operation of the tailstock drive means and the tailstock drive means based on the detection data from the tailstock detection means.

According to the present invention, any position of the tailstock and tailstock on the bed can be detected by the tailstock detection means and tailstock axis detection means, and the control means can detect the detected position. By controlling the operations of the tailstock drive means and the tailstock shaft drive means based on the data, the tailstock and tailstock shaft can be moved to arbitrary positions on the bed.

Therefore, when a plurality of types of workpieces having different lengths are machined by the same machine, a troublesome setup operation such as adjusting a position detection dog position when switching the workpieces to be machined is not necessary. An efficient switching operation can be performed.

Also, when performing unattended automatic operation using the loading device, whether or not the tailstock and the tailstock are retracted at a position where the loading device does not interfere with the tailstock and the tailstock. Can be confirmed, and when the vehicle is at the interference position, it is possible to take measures such as interlocking such that the loading device does not operate or outputting an alarm.

Further, since the positions of both the tailstock and the tailstock shaft can be detected and controlled separately, the tailstock and the tailstock can be moved separately. The tailstock advancing amount can be set to be as short as possible, such as by making the tailstock advancing toward the workpiece side and pressing it against it, and the tailstock operation time of the tailstock is reduced to a very short time. be able to.

Further, if the tailstock and / or tailstock retreat for some reason after the tailstock shaft is pressed against the work and the machining is started, the work can be sufficiently gripped only by the spindle chuck. Work may come off the chuck and damage the inside of the machine. Alternatively, chucking failure occurs, and the work cannot be finished to a predetermined accuracy. However, according to the tailstock according to the present invention, the position of the tailstock and the tailstock can be detected and confirmed even after the start of machining. Detection can be performed, and an alarm can be output or processing can be stopped.

Also, as is well known, when a large number of workpieces are continuously processed, the finished dimensions of the workpieces are not constant and vary, but the position of the tailstock shaft when the tailstock shaft is pressed against the work is defined. By comparing the position with the position, it is possible to detect the magnitude of the work in the longitudinal direction. If the difference exceeds the allowable limit, an alarm may be output.

Further, dimensional data relating to the overall shape formed by the tailstock and the tailstock and dimensional data relating to the shape of the tool rest including the tool are stored in advance in a control device such as an NC device. The control device can recognize mutual interference from the positional relationship between the position of the tailstock and the tailstock shaft detected by the headstock detection means and the tailstock axis detection means and the tool post and the like which are separately recognized. You can also. For example, move the tool post for tool compensation or tool change,
When turning the tool post or when the tool post interferes with the tailstock and tailstock, the control device recognizes this,
It is possible to take measures such as stopping the movement of a tool post or outputting an alarm.

According to a second aspect of the present invention, in the first aspect of the present invention, the tailstock detecting means has a scale with a constant pitch, and is attached to the bed along a moving direction of the tailstock. A first scale attached to the tailstock and moving along the first scale and reading a scale of the first scale; A means provided with a scale at a constant pitch, a second scale attached to the bed or the tailstock along the moving direction of the tailstock, and a second scale attached to the tailstock and attached to the second scale. And a second detector that moves along the second scale and reads the scale of the second scale.

According to the present invention, the positions of the tailstock and the tailstock are detected with reference to a scale having a scale with a constant pitch. In addition, there is an effect that the position can be detected with high accuracy.

According to a third aspect of the present invention, in the second aspect of the present invention, the moving direction of the tailstock and the tailstock shaft is the same direction, and the first scale and the second scale are on a bed. And the same scale attached to.

According to the present invention, since the position of both the tailstock and the tailstock shaft is detected on the same scale, the function and effect of the second aspect of the present invention are provided. , The structure of the whole device can be simplified,
This has the effect and effect that it can be installed in a limited narrow space.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the entire lathe according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.

As shown in FIG. 1, the lathe according to the present embodiment has the same basic configuration as that of the conventional lathe (FIG. 3) except for the part relating to the tailstock. Therefore, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 2, a tailstock 20 according to the present embodiment includes a tailstock 21 mounted on the bed 1 so as to be movable in the directions indicated by arrows B-C. A tailstock shaft 22 which is supported and is also movable in the directions indicated by arrows BC by a hydraulic mechanism, a scale 23 provided on the bed 1 below the tailstock 21, The first detector 24 and the second detector 25 that are movable along the longitudinal direction, and the tailstock 21 and the tailstock 21 are moved based on the detection data of the first detector 24 and the second detector 25. Tailstock 2
And a tailstock / shaft control means 35 for controlling the operation of No. 2 as a basic configuration. The forward / backward movement of the tailstock shaft 22 is switched by the switching valve 31.

The tailstock 21 is driven by a driving means composed of a rack (not shown), a pinion (not shown) and a driving motor (not shown), similarly to the above-mentioned conventional one, as indicated by arrows BC. The first detector 24 is attached to the lower end of the first detector 24 via a mounting bracket 30.
Is installed. Also, as shown in FIG.
2, an inner space 21a is formed. As shown in FIG. 2, a drive rod 27 is attached to a side wall of the inner space 21a via bearings 29,29. The end of the drive rod 27 in the direction of arrow B is the same as the arrow B of the tailstock shaft 22.
The drive rod 27 is fixed to an end portion in the direction via a mounting plate 26, and moves in the same direction as the tailstock shaft 22 moves in the directions indicated by arrows BC. The upper end of the support stay 28 is fixed to the drive rod 27 between the bearings 29, 29, and the second detector 25 is fixed to the lower end thereof. Thus, the first detector 24 is
Moves on the scale 23 in the same direction with the movement of
Of the scale 23 with the movement of the tailstock shaft 22
Move up in the same direction. Note that covers 32 and 33 are provided on the side surfaces of the tailstock 21 in the directions indicated by arrows B and C, respectively.

The scale 23 is provided with graduations at a constant pitch in the longitudinal direction.
The bed 1 is mounted and fixed on the bed 1 along the direction of arrow BC, which is the direction of movement of the bed 1. The first detector 24 and the second detector 25 are engaged with the scale 23, read the scale thereof, and output predetermined detection data.
Form two linear encoders. In this example, an incremental photoelectric linear encoder in which the first detector 24 and the second detector 25 detect a relative movement amount is used.

The tailstock / shaft control means 35 comprises the first
A tailstock position detector 36 for calculating the position on the bed 1 at the end of the tailstock 21 in the direction indicated by the arrow A in the absolute coordinate system by inputting the detection data of the detector 24, and the second detection Axis detection unit 37 for inputting the detection data of the box 25 and calculating the position on the bed 1 of the end of the tailstock shaft 22 in the direction indicated by the arrow A in the absolute coordinate system. The tailstock / shaft control unit 38 controls the operation of the tailstock shaft 22. The tailstock / shaft control means 38 is incorporated in a numerical control device 39 for controlling the main shaft and the like, and the tailstock / shaft control unit 38 includes an operation program stored in the numerical control device 39. The operation of the tailstock 21 and the tailstock shaft 22 is controlled based on the data of the tailstock position detection unit 36 and the tailstock shaft position detection unit 37, and the position data calculated by the tailstock shaft position detection unit 37. The numerical control device 39 is a known device, and a detailed description thereof will be omitted.

According to the lathe according to the present embodiment having the above configuration, the scale 23, the first detector 24 and the second detector 25, the tailstock position detector 36 and the tailstock shaft position detector are provided. The position of the tailstock 21 and the tailstock 22 on the bed 1 in the absolute coordinate system can be detected by the unit 37.

The tailstock / shaft controller 38 checks the positions of the tailstock 21 and the tailstock 22 calculated by the tailstock position detector 36 and the tailstock shaft position detector 37 at any time. The feedback control is performed, and the tailstock 21 and the tailstock 2
2 can be moved to any position on the bed 1. Therefore, for example, when a plurality of types of workpieces having different lengths are machined by the same machine, an operation program in which an operation position is set according to the dimensions of the workpiece is created once, and when the machining workpiece is subsequently switched. In this case, a cumbersome setup operation such as adjusting the dog position is not required, and an extremely efficient switching operation can be performed.

Further, since the positions of the tailstock 21 and the tailstock shaft 22 are detected by the linear encoder, the positions can be detected with high accuracy. Since the positions can be detected and these can be moved separately by feedback control, the tailstock 21 is moved closer to the work at a high speed, and then the tailstock shaft 22 is advanced toward the work and pressed against the work. For example, the feed amount of the tailstock shaft 22 can be set as short as possible. As described above, the tailstock operation time of the tailstock device 20 can be reduced to a very short one.

Further, since the absolute positions of the tailstock 21 and the tailstock shaft 22 on the bed 1 can be confirmed, the unloading device and the tailstock 21 can be used even when unmanned automatic operation using the loading device is performed. The tailstock 21 and the tailstock shaft 22 can be checked at a position where they do not interfere with the tailstock shaft 22 to determine whether or not the tailstock 21 and the tailstock shaft 22 are retracted. It can also take measures such as locking and outputting an alarm.

When the tailstock 21 and the tailstock 22 are retracted due to some cause such as a failure of the switching valve 31 after the tailstock shaft 22 is pressed against the work and the machining is started, the work is performed only by the spindle chuck 3. There is a possibility that the work cannot be sufficiently held and the work comes off the chuck 3 to damage the inside of the machine. Alternatively, chucking failure occurs, and the work cannot be finished to a predetermined accuracy. However,
According to the tailstock 20, since the positions of the tailstock 21 and the tailstock 22 can be detected and confirmed even after the start of machining, such retraction of the tailstock 21 and the tailstock 22 can be prevented. Detection can be performed, and an alarm can be output or processing can be stopped.

As is well known, when a large number of workpieces are continuously machined, the finished dimensions of the workpieces are not constant and vary, but the position of the tailstock shaft 22 when the tailstock shaft 22 is pressed against the work is determined. Is compared with the specified position, it is possible to detect the magnitude in the length direction of the work, and if the difference exceeds the allowable limit, it is possible to take measures such as outputting an alarm.

The dimensional data relating to the overall shape formed by the tailstock 21 and the tailstock shaft 22 and the dimensional data relating to the shape of the tool rest 6 including the tool are stored in the numerical controller 39 in advance. From the positional relationship between the positions of the tailstock 21 and the tailstock shaft 22 detected by the tailstock position detection unit 36 and the tailstock shaft position detection unit 37 and the tool rest 6 which is separately recognized, the numerical controller 39 is used. Mutual interference can be recognized. For example, if the tool rest 6 interferes with the tailstock 21 and the tailstock shaft 22 when the tool rest 6 is moved or the tool rest 6 is turned for tool correction or tool change, the numerical controller is used. 39 recognizes this and can take measures such as stopping the movement of the tool rest 6 or outputting an alarm.

In this embodiment, since the position of both the tailstock 21 and the tailstock shaft 22 is detected by one scale 23, the structure of the entire apparatus can be simplified. It can be installed in a limited space. However, if the installation space is not limited and the structure may be slightly complicated, the first detector 2
4, two scales 23 respectively corresponding to the second detectors 25 may be provided on the bed 1. In this case, a scale 23 corresponding to the second detector 25 may be attached to the tailstock 21.

In this embodiment, the scale 23, the first detector 24, and the second detector 25 are covered by the covers 32, 33, the metal belt 10, and the like. Detection can be prevented.

Although the embodiments of the present invention have been described in detail above, it is needless to say that the specific embodiments of the present invention are not limited to these embodiments. Although used, the invention is not limited thereto, and various linear encoders such as a magnetic encoder, an electromagnetic induction encoder, and a capacitance encoder can be used.

Although the linear encoder is of the incremental type, it is not limited to this, and may be of course an absolute type. In this case, since the absolute position can be detected by the first detector 24 and the second detector 25, the tailstock position detecting unit 36 and the tailstock shaft position detecting unit 37 described above are unnecessary. The detection data from the first detector 24 and the second detector 25 may be directly input to the tailstock / shaft control unit 38.

In this embodiment, the tailstock 21 and the tailstock shaft 22 are moved in the same direction. However, for example, the tailstock 21 moves in a direction perpendicular to the longitudinal direction of the bed 1. Such a configuration may be employed. In this case, it is necessary to provide two scales 23 individually corresponding to the first detector 24 and the second detector 25, respectively.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a lathe equipped with a tailstock according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view in the direction of arrows AA in FIG.

FIG. 3 is a perspective view showing a lathe equipped with a conventional tailstock;

[Explanation of symbols]

 Reference Signs List 20 tailstock 21 tailstock 22 tailstock shaft 23 scale 24 first detector 25 second detector 26 mounting plate 27 drive rod 28 support stay 29 bearing 30 mounting bracket 31 switching valve 32, 33 cover 35 tailstock Base / axis control means 36 Tailstock position detection unit 37 Tailstock axis position detection unit 38 Tailstock / axis control unit 39 Numerical control device

Continued on the front page (72) Inventor Masahiro Yamane 106 Kita-Gun Yamamachi, Yamatokoriyama-shi, Nara Prefecture Mori Seiki Seisakusho Co., Ltd.

Claims (3)

[Claims] 1. A tailstock provided on a bed of a machine tool and movable in a direction of coming and going with respect to a main spindle; and a tailstock supported on the tailstock so as to advance and retreat with respect to the main spindle. Tailstock that advances to the side and presses against the work gripped by the spindle; tailstock drive means for moving the tailstock in the separation / contact direction; and moving the tailstock shaft in the advance / retreat direction. Tailstock driving means, tailstock detection means for detecting an arbitrary position of the tailstock on the bed, and tailstock detection means for detecting an arbitrary position of the tailstock on the bed. And a control means for controlling the operation of the tailstock drive means and the tailstock drive means based on the detection data from the tailstock detection means and the tailstock axis detection means. apparatus. 2. The tailstock detection means has a scale with a fixed pitch, a first scale attached to the bed along a moving direction of the tailstock, and a first scale attached to the tailstock. A first detector that moves along the first scale and reads a scale of the first scale; the tailstock detection means includes a scale with a constant pitch; And a second scale attached to the bed or tailstock along the moving direction of the second and a tailstock attached to the tailstock and moved along the second scale to read the scale of the second scale. And a second detector.
The tailstock of the machine tool according to the above. 3. The tailstock and the tailstock shaft are moved in the same direction, and the first scale and the second scale are constituted by the same scale attached to a bed. The tailstock of the machine tool according to the above.