Headstock assembly for machine tool

A headstock assembly for a machine tool includes a mount having a female threaded bore, a headstock mounted slidably relative to the machine base, a drive member mounted on the headstock, a spindle, and a spindle extension. The spindle has an intermediate segment disposed in a chamber of the headstock and coupled to be driven by the drive member so as to permit the spindle to rotate about a spindle axis. The spindle extension is coupled to be rotatable with the spindle, and has a male threaded segment configured to be in threaded engagement with the female threaded bore so as to permit the headstock to be linearly moved relative to the mount.

FIELD

The disclosure relates to a headstock assembly, more particularly to a headstock assembly for a machine tool such as a threading machine.

BACKGROUND

Taiwanese utility model patent no. M487160 discloses a conventional headstock assembly9for a threading machine (seeFIG. 1) in which a headstock91is slidably mounted on a guide rail unit90in a linear direction, a spindle shaft92is rotatably mounted in the headstock91, and a chuck member93for gripping a workpiece (W) is coupled to a right end of the spindle shaft92so as to rotate with the spindle shaft92. In the conventional headstock assembly, the linear motion of the headstock91is driven by a drive member94, and the rotary motion of the spindle shaft92is driven by another drive member (not shown).

SUMMARY

Therefore, an object of the disclosure is to provide a novel headstock assembly for a machine tool. With the provision of the headstock assembly, linear motion of a headstock and rotary motion of a spindle can be driven by the same drive member. In addition, the headstock assembly has a relatively simple structure and is easy to assemble.

According to a first aspect of the disclosure, a headstock assembly for a machine tool is provided. The machine tool is used for machining a workpiece, and includes a machine base, and a guide rail unit mounted on the machine base and extending along a longitudinal direction. The headstock assembly includes a mount, a headstock, a drive member, a spindle, and a spindle extension. The mount is secured to the machine base, and has a female threaded bore. The headstock is mounted slidably on the guide rail unit, and is spaced apart from the mount in the longitudinal direction. The drive member is mounted on the headstock. The spindle extends along a spindle axis in the longitudinal direction, and is rotatably mounted to the headstock. The spindle is coupled to be driven by the drive member to rotate about the spindle axis. The spindle extension extends along the spindle axis, and is coupled to be rotatable with the spindle. The spindle extension has a male threaded segment which is configured to be in threaded engagement with the female threaded bore so as to permit the headstock to be linearly moved relative to the mount in the longitudinal direction.

According to a second aspect of the disclosure, a headstock assembly for a machine tool is provided. The machine tool is used for machining a workpiece, and includes a machine base, and a guide rail unit mounted on the machine base and extending along a longitudinal direction. The headstock includes a headstock, a spindle, a chuck member, a drive member, a mount, and a spindle extension. The headstock is mounted slidably on the guide rail unit, and has a left end wall and a right end wall which is spaced apart from the left end wall in the longitudinal direction to define a chamber. The left end wall has a left inner bearing surface which defines a left bore extending to be communicated with the chamber. The right end wall has a right inner bearing surface which defines a right bore extending to be communicated with the chamber. The spindle extends along a spindle axis in the longitudinal direction to terminate at a left end and a right end, and has an intermediate segment, a left journal region, and a right journal region. The intermediate segment is disposed between the left and right ends in the chamber, and has a main region and a juncture region proximate to the right end. The left journal region is disposed between the left end and the main region, and is journaled on the left inner bearing surface. The right journal region is disposed between the right end and the juncture region, and is journaled on the right inner bearing surface. The chuck member for gripping the workpiece is coupled to the right end of the spindle so as to permit the chuck member to rotate with the spindle about the spindle axis. The drive member is mounted on the headstock and has an output shaft which is rotatable about a shaft axis, and which is coupled to the intermediate segment in the chamber so as to drive the spindle to rotate about the spindle axis. The mount is secured to the machine base and is disposed leftwardly of the guide rail unit. The mount has a female threaded bore extending along the spindle axis. The spindle extension extends along the spindle axis to terminate at a proximate end and a distal end. The proximate end is coupled to the left end of the spindle to permit the spindle extension to rotate with the spindle. The distal end is disposed leftwardly of the mount. The spindle extension has a male threaded segment which is disposed between the proximate and distal ends, and which is configured to be in threaded engagement with the female threaded bore so as to permit the headstock to be linearly moved relative to the mount in the longitudinal direction.

DETAILED DESCRIPTION

Before the disclosure is described in greater detail, it should be noted that where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements, which may optionally have similar characteristics.

With reference toFIGS. 2 to 5, a headstock assembly for a machine tool according to a first embodiment of the disclosure is shown. The machine tool is used for machining a workpiece (W) (only shown inFIG. 4), and includes a machine base100and a guide rail unit90which is mounted on the machine base100, and which extends along a longitudinal direction (X).

The headstock assembly includes a mount10, a headstock20, a drive member30, a spindle40, a chuck member50for gripping the workpiece (W), and a spindle extension60.

The mount10is secured to the machine base100, and has a female threaded bore11(seeFIGS. 4 and 5). In this embodiment, the mount10is disposed leftwardly of the guide rail unit90, and the female threaded bore11extends along a spindle axis (L) in the longitudinal direction (X).

The headstock20is mounted slidably on the guide rail unit90, and is spaced apart from the mount10in the longitudinal direction (X).

In this embodiment, the headstock20has a left end wall21, a right end wall22, a front end wall23, a rear end wall24, and a bottom wall25, and defines therein a chamber200. The right end wall22is spaced apart from the left end wall21in the longitudinal direction (X) to define the chamber200. The rear end wall24is spaced apart from and is opposite to the front end wall23in a transverse direction (Y) relative to the longitudinal direction (X). As shown inFIG. 5, the left end wall21has a left inner bearing surface211which defines a left bore212extending to be communicated with the chamber200. The right end wall22has a right inner bearing surface221which defines a right bore222extending to be communicated with the chamber200.

Furthermore, the bottom wall25of the headstock20is secured on a platform26which is slidably mounted on the guided rail unit90.

The spindle40extends along the spindle axis (L) in the longitudinal direction (X), and is rotatably mounted to the headstock20. The spindle40is coupled to be driven by the drive member30to rotate about the spindle axis (L).

As shown inFIG. 5, the spindle40extends along the spindle axis (L) to terminate at a left end401and a right end402, and has an intermediate segment403, a left journal region406, and a right journal region407. The intermediate segment403is disposed between the left and right ends401,402in the chamber200, and has a main region404and a juncture region405proximate to the right end402. The left journal region406is disposed between the left end401and the main region404, and is journaled on the left inner bearing surface211. The right journal region407is disposed between the right end402and the juncture region405, and is journaled on the right inner bearing surface221. Moreover, the spindle40is in the form of a tube.

The chuck member50is coupled to the right end402of the spindle40so as to permit the chuck member50to rotate with the spindle40about the spindle axis (L), to thereby allow rotation of the workpiece (W) relative to a tool (not shown).

Referring back toFIGS. 2 and 4, it can be seen that the drive member30is mounted on the headstock20and has an output shaft311which is rotatable about a shaft axis (S), and which is coupled to the intermediate segment403in the chamber200so as to drive the spindle40to rotate about the spindle axis (L).

In this embodiment, the shaft axis (S) extends in the transverse direction (Y), the drive member30has a motor body31secured on an outer surface of the rear end wall24, and the output shaft311extends from the motor body31through the rear end wall24and the chamber200so as to be rotatably mounted to the front end wall23.

The spindle extension60extends along the spindle axis (L), and is coupled to be rotatable with the spindle40. The spindle extension60has a male threaded segment61which is configured to be in threaded engagement with the female threaded bore11so as to permit the headstock20to be linearly moved relative to the mount10in the longitudinal direction (L).

In this embodiment, the spindle extension60extends along the spindle axis (L) to terminate at a proximate end601and a distal end602. The proximate end601is coupled to the left end401of the spindle40to permit the spindle extension60to rotate with the spindle40. The distal end602is opposite to the proximate end601in the longitudinal direction (X) and is disposed leftwardly of the mount10. The male threaded segment61is disposed between the proximate and distal ends601,602.

In this embodiment, the headstock assembly further includes a left anti-friction member71, a right anti-friction member72, a tubular worm32, and a worm gear41.

As best shown inFIG. 5, the left anti-friction member71is disposed between the left journal region406and the left inner bearing surface211. The right anti-friction member72is disposed between the right journal region407and the right inner bearing surface221.

Referring back toFIGS. 2 and 4, it can be observed that the tubular worm32is sleeved and mounted on the output shaft311to permit the tubular worm32to rotate with the output shaft311about the shaft axis (S). As shown inFIG. 5, the worm gear41is mounted on the main region404of the intermediate segment403of the spindle40, and is configured to mesh with the tubular worm32so as to permit the worm gear41, together with the spindle40, to be driven to rotate about the spindle axis (L).

In this embodiment, the machine tool is used for threading the workpiece (W). To produce a threaded member with desired pitch and outer dimension, the spindle extension60and the mount10may be replaced.

With the provision of the single drive member30, the workpiece (W) can be driven to rotate about the spindle axis (L) and to slide in the longitudinal direction (X).

FIGS. 6 and 7illustrate a headstock assembly for a machine tool according to a second embodiment of the disclosure. The second embodiment is similar to the first embodiment except that the main region404and the juncture region405of the intermediate segment403of the spindle40are spaced apart in the longitudinal direction (X) by a gap400.

In addition, in the second embodiment, the headstock assembly further includes a first electromagnetic clutch70and a second electromagnetic clutch80.

The first electromagnetic clutch70is disposed to couple the main region404to the juncture region405of the intermediate segment403of the spindle40such that when the first electromagnetic clutch70is switched on, the juncture region405is permitted to be rotated with the main region404, and such that when the first electromagnetic clutch70is switched off, the juncture region405is unable to rotate with the main region404.

The second electromagnetic clutch80is disposed to couple the left end401of the spindle40to the proximate end601of the spindle extension60such that when the second electromagnetic clutch80is switched on, the spindle extension60is permitted to be rotated with the spindle40, and such that when the second electromagnetic clutch80is switched off, the spindle extension60is unable to rotate with the spindle40.

When both of the first and second electromagnetic clutches70,80are switched on, the workpiece is driven to rotate and to move linearly relative to a tool, and the headstock assembly of the second embodiment can be used for threading a workpiece.

When the first electromagnetic clutch70is switched on and the second electromagnetic clutch80is switched off, the workpiece is merely driven to rotate relative to a tool. When the second electromagnetic clutch80is switched on and the first electromagnetic clutch70is switched off, the workpiece is merely driven to move linearly relative to a tool.

FIGS. 8 and 9illustrate a headstock assembly for a machine tool according to a third embodiment of the disclosure. The third embodiment is similar to the first embodiment except that the drive member30is replaced by a drive member30′. The drive member30′ is disposed in the chamber200, and has a stator31′ and a rotor32′. The stator31′ is configured to surround the spindle40. The rotor32′ extends in the longitudinal direction (X) to terminate a rotor end321′ that serves as the output shaft311′, and is coaxially and integrally formed with the intermediate segment403of the spindle40.