GB2206826A

GB2206826A - Grinding machine

Info

Publication number: GB2206826A
Application number: GB08811940A
Authority: GB
Inventors: Jivko Steev Atanassov
Original assignee: TS NII METALOREZH MASH
Current assignee: TS NII METALOREZH MASH
Priority date: 1987-05-20
Filing date: 1988-05-20
Publication date: 1989-01-18
Also published as: JPH0197550A; GB8811940D0; BG47228A1; DE3817161A1

Description

a o A 2206826 CYLINDRICAL GRINDING MACHINE This invention relates to a

cylindrical grinding machine with numerical control which can be used for grinding chuck-clamped and centre-type stepped workpieces such as sleeves, flanges, gear wheels, shafts etc.

Bulgarian patent specification No.37414 discloses a numerically controlled cylindrical grinding machine for internal and external grinding which comprises a base having transverse slideways mounted at the rear, on which there is disposed a carriage for external grinding. The base also has longitudinal slideways and on these are mounted a left longitudinally sliding carriage and a right longitudinally sliding carriage. A spindle unit with a chuck for clamping is mounted on the left- hand carriage. On the right-hand carriage there is mounted a transversely sliding carriage which carries a spindle unit for internal grinding. The left longitudinal carriage and the right longitudinal carriage are connected respectively to separate independent hightorque electric motors.

A drawback of this known machine lies in its limited technological potential because it cannot be used for grinding centre-type workpieces.

It is therefore a general object of this invention to develop a numerically controlled cylindrical grinding machine which can take chuckclamped or centre-type workpieces.

According to the invention there is provided a machine for cylindrical grinding of a workpiece, compr4Lsing:

a base having longitudinal and transverse slideways; a carriage for external grinding mounted on k A is the transverse slideways; a lefthand carriage mounted on the longitudinal slideways and driven by a first electric motor; a right-hand carriage mounted on the longitudinal slideways and driven by a second electric motor; an internal-grinding carriage mounted so as to slide transversely on the right-hand carriage; wherein the left-hand carriage is adapted to support the workpiece at its left-hand end by means of either a headstock centre or a clamp, and the internalgrinding carriage is adapted to apply a grinding device to the right-hand end of the workpiece when held by the clamp, or to support the righthand end of the workpiece by means of a tailstock centre when the headstock centre of the left-hand carriage is in operation.

One way of inter-changing the clamp and the headstock centre may be to have the left-hand carriage carry a two-position table, on which in turn are mounted a spindle carrying the headstock centre and a spindle carrying the clamp, rotation of the table between its two positions bringing the headstock centre or the clamp into alignment with the workpiece.

Further, the internal-grinding carriage may have mounted on it a multiposition head, on which are mounted the grinding device and a device for supporting the tailstock centre, these two devices being brought into alignment with the workpiece by rotation of the head.

There can also be a modification in which there are provided three grinding spindles mounte ' d on a multiposition head, while the tailstock has a manually clamped tailstock centre.

k 0 is Advantageouslyr a tailstock capable of automatic exchange of tailstock centres may be used. In this case, the tailstock may consist of a body containing a poppet sleeve in the front end of which there is machined a cone for automatic clamping of the tailstock centre, a double-acting cylinder being fixed to its rear end. In a central hole of the poppet sleeve there is disposed a rod in the front end of which there is fastened a sleeve with balls in it, and on its rear end there are mounted disc springs, limited by a regulable nut. To the rear end of the body there is mounted a single-acting cylinder.

In certain embodiments a grinding spindle and a tailstock may be disposed both on the same side of the internal-grinding carriage.

Cylindrical grinding machines according to the invention make it possible to grind chuck-clamped as well as centre-type workpieces. Moreover, the machine makes it possible to grind in arbitrary sequence centre-type workpieces of:different size and with different arrangement of the centre holes by a manual or automatic change of different types of tailstock centres. It is possible to develop on the basis of the machine a flexible manufacturing cell for grinding chuck-clamped and centre-type workpieces.

For a better understanding of the invention, various embodiments of it will now be described with reference to the accompanying drawings, in which:

Fig.1 is a plan view of a first embodiment; Fig.2 shows a tailstock with automatic clamping and release of the tailstock centre; Fig.3 is a plan view of a second embodiment; Fig. 4 is a plan view of a third embodiment; Fig.5 is a plan view of a fourth embodiment; Fig.6 shows different tailstock centres for 4 1 is three different types of centre-type workpieces; Fig.7 is a front view of a magazine for automatic change of grinding mandrels and tailstock centres; Fig.8 is a plan view of a fifth embodiment; Fig.9 is a plan view of a sixth embodiment; Fig.10 shows a standard tailstock; Fig.11 is a plan view of a seventh embodiment; Fig.12 is a plan view of an eighth embodiment. The cylindrical grinding machine with numerical control for the grinding of chuck-clamped and centre-type workpieces consists of a base 1 (Fig.1), on the rear part of which transverse sideways 11 are fixed. An external grinding carriage 12 connected to a high-torque electric motor 16 travels on the slideways 11. A device for axial positioning 20 is mounted on the external grinding carriage 12. The base 1 also has longitudinal slideways 57 on which are mounted a lefthand longitudinally sliding carriage 2 and a righthand longitudinally sliding carriage 7. On the righthand carriage is mounted a transversely sliding internal-qrinding carriage 8 and a high torque clectric motor 15. On the top part of the internal grinding carriage 8 is mounted a multiposition head 49, which in this example is a twoposition capstan head, with oppositely disposed high-frequency electric grinding spindle 32 and tailstock 36 which allow automatic change of the grinding mandrels 35 and tailstock centres 33 respectively. A magazine 52 is fixed to the right vertical part of the base 1 and carries a tool disc 34 for automatic change of grinding mandrels 35 or tailstock centres 33 arranged to the right of IC-1.1e internal-grinding carriage 8. On the top part of the left-hand carriage 2 there is mounted a two-position table 53, rotating by 180' between positions, and on the rear top part of this there is mounted a spindle unit 55 with a rigidly fastened standard headstock centre 6 and a device 5 for the transmission of a torque to the centre-type workpiece 19. On the front top part of the two-position table 53 and facing. oppositely to the spindle unit 55 is mounted a spindle unit 3 with chuck 54 for clamping a chuck-clamped workpiece 51. The left-hand carriage 2 and the righthand carriage 7 are connected respectively to synchronised high-torque electric motors 13 and 14. On the spindle units 55 and 3 there are mounted two identical sharpening devices 4. To the front part of the base 1 there are fastened rigidly a wide-range device for active checking 17 and a sharpening device 18 for the internal-grinding disc.

As Fig.2 shows, the tailstock 36, which is fastened to the multi-position head 49, comprises a body 30 containing a poppet sleeve 37. The left end of the sleeve 37 has machined in it a special cone for automatic clamping of the:tailstock centre 33, and to its right end there is fastened rigidly a double-acting cylinder 44 with piston 43. The poppet sleeve 57- has a central bor e in which there is inserted a rod 40, to the left end of which there is fastened rigidly a sleeve 38 carrying balls 39, and on its right end there are mounted disc springs 42, limited by a regulable nut 41. To the right end of the body 30 there is fastened a single-acting cylinder 46 with piston 45. Between the cylinders 44 and 46 there is disposed a spring 48.

The operation of this numerically-controlled cylindrical grinding machine is as follows:

At the end of the cycle (Figures 1 and 2) the left-hand carriage 2 and the right-hand carriage 7 are moved along the longitudinal slideways of the base 1 until they reach their end positions. When grinding t 1 is centre-type workpieces on command of the NC system the two-position table 53 is rotated so that the spindle unit 55 comes into its working position opposite to the tailstock 36 which is mounted on the multi-position head 49. The right-hand carriage 7 is displaced on manual or automatic command by means of the high-torque electric motor 14 to the left at the distance preset by the programme between the standard headstock centre 6 and the tailstock centre 33 in dependence on the length of the machined workpiece and the disposition and size of its right centring hole. After the manual or automatic loading of the machine with a centre-type workpiece 19, the external grinding carriage 12 is moved forward by means of the hightorque electric motor 16 (axis X1) until the sensor of the device for axial positioning 20 takes its programmed working position. The centretype workpiece 19 is then moved to the right by simultaneous and singledirectional motion of the left-hand carriage 2 (axis Z1) and the righthand carriage 7 (axis Z2), effected by synchronous rotation of the hightorque electric motors 13 and 14, until the sensor of the device for axial positioning 20 touches the programmed face surface of the workpiece 19 and thus effects its axial orientation with regard to the external grinding carriage 12. The longitudinal positioning of the centre-type workpiece 19 in the case of infeed grinding, and its motion in the case of longitudinal grinding, is effected by simultaneous and single- directional motion of both carriages 2 and 7. The face grinding of the centretype workpiece 19 is effected by motion to the right of the left- hand carriage 2 only, since the tailstock centre 33 can move a certain distance in the axial direction within the tailstock 36, as shown by the arrow in Figure 1, because of the allowable compression t of the spring 48. The measuring of the external cylindrical surfaces of the centre-type workpiece 19 during the grinding is effected by the wide- range device for active checking 17. The alignment of the tailstock centre 33 with the standard headstock centre 6 is effected by displacing the transverse carriage 8 (axis X2). The release of the centre-type workpiece 19 is effected by hydraulic displacement of the piston 45 of the single-acting cylinder 46, compressing the spring 48 and moving the tailstock centre 33 to its right-hand position with respect to the body 30 of the tailstock 36. A new tailstock centre 33 is positioned in the cone of the poppet sleeve 37 by means of the tool disc 34 of magazine 52 with the tailstock 36 in its right-hand, non-working position. by longitudinal motion of the right-hand carriage 7 with the piston 43 of the double-acting cylinder 44 in its left-hand (front) position. After positioning the new tailstock centre 33 in the cone of the poppet sleeve 37 it is pressed securely into position by the disc springs 42 by means of the regulable"nut 41, the rod 40, the sleeve 38 and the balls 39 after moving the piston 43 to its right-hand (end) position. When changing from a centre-type workpiece 19 to a chuck-clamped workpiece, the two-position table 53 and the multiposition head 49 are rotated by 180' by command of the NC system so that the spindle unit 3 with chuck 54 comes opposite to the high-frequency electric grinding spindle 32 with the grinding mandrel 35 fixed in it. When it, is required to change the grinding mandrel 35, this i,s effected from the magazine 52 in a manner analogous to that of the change of the tailstock centre 33. The grinding of the chuck-clamped workpiece is effected by longitudinal feed of the left-hand carriage 2 (axis Z1), cross feed of the external grinding carriage (axis X1), A a longitudinal feed of the right-hand carriage 7 (axis Z2) and cross feed of the internal-grinding carriage 8 (axis X2). Sharpening of the internal- grinding disc, fastened to the grinding mandrel 35, is effected by the sharpening device 18 at respective feeds of the righthand carriage 7 and the internal-grinding carriage 8.

In a second embodiment of the invention (Fig.3) the tailstock 36 is replaced by a second highfrequency electric grinding spindle 32 with automatic change of the grinding mandrels 35 or tailstock centres 33, and the spindle unit 55 for centre-type workpieces carries an axially movable headstock centre 47.

The operation of this embodiment is analogous to the first. The axially movable headstock centre 47 makes possible face grinding of the centretype workpiece 19 by motion of only the left-hand carriage 2. The tailstock centre 33 rotates together with the centre-type workpiece 19.

In a third embodiment of the invention (Fig.4) the spindle unit 3 with either a chuck 54 (as shown) or a standard headstock centre 6 is mounted directly on the left-hand carriage 2. The operation of this embodiment is analogous to that of the first embodiment, with the exception that the resetting when replacing a chuck-clamped workpiece by a centretype workpiece 19 is effected by manual fastening of a standard headstock centre 6 after removal of the chuck 54.

In a fourth embodiment of the invention (Fig.5) the internal-grinding carriage 8 has a highfrequency electric grinding spindle 32 with automatic change of the grinding mandrels 35 and a tailstock 3,6 with automatic change of the tailstock centres 33 mounted parallel and adjacent to each other. Fig.6 shows three different tailstock centres 33. To the 3 r right of the base 1 there is mounted a magazine 50 (Fig.7) with the tool disc 34 for automatic change of the grinding mandrels 35 and tailstock centres 33 arranged to the left of the internal-grinding carriage 8. Here. operation is analogous to the first embodiment with the following differences: the change of the grinding mandrels 35 and the tailstock centres 33 is effected at two different transverse positions of the internal-grinding carriage 8; the change is effected in the forward working position of the highfrequency electric grinding spindle 32 and the tailstock 33 by means of the tool disc 34 of magazine 50, located to the left of the internal-grinding carriage 8.

In a fifth embodiment-of the invention (Fig.8) the internal-grinding carriage 8 carries only a highfrequency electric grinding spindle 32 with automatic change of grinding mandrels 35 and tailstock centres 33, while on the spindle unit 55 is mounted an axially movable headstock centre 47. The magazine 50 with the tool disc 34 for automatic change of the grinding mandrels 35 and tailstock centres 33 is mounted as in Figure 7. The operation of this embodiment is analogous to that of the first and second embodiments.

In a sixth embodiment of the machine (Fig.9) three standard highfrequency electric grinding spindles 31 and one standard tailstock 31 are mounted on the multiposition head 49 which in this case is a fourposition capstan head. Figure 10 shows a standard tailstock 21, in the poppet sleeve 23 of which is mounted a standard tailstock centre 22. The poppet sleeve 23, mounted in a ball sleeve 24, is connected rigidly by means of the rod 28 to the piston 26 of single-acting cylinder 27 fastened to the body 29. Between the poppet sleeve 23 and the sing,le- acting is cylinder 27 there is mounted a spring 25. The operation of this embodiment is analogous to the first embodiment, but without automatic change of the grinding mandrels of the standard high-frequency electric grinding spindles 31 and the standard tailstock centre 33 of the standard tailstock 21. When grinding centre-type workpieces, the multiposition head 49 is rotated so that the standard tailstock 21 faces the spindle unit 55. When grinding chuck-clamped workpieces, one of the three standard high-frequency electric grinding spindles 31 is placed opposite to the spindle unit 3.

In a seventh embodiment of the machine (Fig.11), a grinding spindle 9 with belt drive and a standard tailstock 21 are mounted parallel and adjacent to each other on the internal-grinding carriage 8, and on the left-hand carriage 2 there is mounted a spindle unit 3 in the conical hole of which there is mounted a standard headstock centre 6, which can be replaced by a chuck 54 in a similar way.to the third embodiment. The placing and removal of the standard tailstock centre 22 on and from the standard tailstock 21 is effected manually. The grinding of centre-type workpieces 19 is effected with the grinding mandrel of the belt- driven grinding spindle 9 removed, as shown in the Figure. The grinding of centre-type workpieces 19 and chuck-clamped workpieces 51 is effected in two different positions of the transverse slide 8.

In an eighth embodiment of the machine (Fig.12), a general-purpose beltdriven spindle 9 with special tailstock centre 10 is mounted on the internalgrinding carriage, while on the left-hand carriage 2 there is mounted a spindle unit 3 in the conical hole of which there is mounted an axially movable headstock centre 47. In this embodiment the grinding of both types of workpieces is effected in one position of the internal-grinding carriage 8 and with manual change of the special tailstock centre 10, grinding mandrels 35, movable headstock centre 47 and chuck 54.

It is to be understood that the terms 'left' and 'right' are used throughout the specification for convenience and could be interchanged without departing from the scope of the invention.

j r 4 is

Claims

CLAIMS:

A machine for cylindrical grinding of a workpiece, comprising:

a base having longitudinal and transverse slideways; a carriage for external grinding mounted on the transverse slideways; a left-hand carriage mounted on the longitudinal slideways and driven by a first electric motor; a right-hand carriage mounted on the longitudinal slideways and driven by a second electric motor; an internal-grinding carriage mounted so as to slide transversely on the right-hand carriage; wherein the left-hand carriage is adapted to support the workpiece at its left-hand end by means of either a headstock centre or 4 clamp, and the internal grinding carriage is adapted to apply a grinding device to the right-hand end of the workpiece when held by the clamp, or to support the right-hand end of the workpiece by means of a tailstock centre when the headstock centre of the left-hand carriage is in operation.
2. Grinding machine according to claim 1, wherein the left-hand carriage carries a two-position table, on which in turn are mounted a spindle carrying the headstock centre and a spindle carrying the clamp, rotation of the table between its two positions bringing the headstock centre or the clamp into alignment with the workpiece.
3. Grinding machine according to claim 1, wherein the headstock centre and the clamp are exchanged manually.
4. Grinding machine according to any preceding 1 1 1 claim, wherein the headstock centre is axially movable.
5. Grinding machine according to any preceding claim, wherein the device for supporting the tailstock centre is a tailstock.
6. Grinding machine according to claim 5. wherein the tailstock is capable of automatic exchange of tailstock centres.
7. Grinding machine.according to any preceding claim, wherein the grinding device is a high-frequency electric grinding spindle with automatic change of grinding mandrels.
8. Grinding machine according to claim 5, wherein the internal-grinding carriage carries a multi-position head on which are mounted the grinding device and the tailstock, these two devices being capable of being brought into alignment with the workpiece by rotation of the head.
9. Grinding machine according to claim 8 and having three grinding devices, wherein the multi position head has four positions so as to allow any of the three grinding devices or the tailstock to move into alignment with the workpiece by rotation of the head.
10. Grinding machine according to claim 6 or 7,.

wherein the automatic change of mandrels, or tailstock centres. or both, is performed by a magazine having a tool disc disposed to the right of the internal grinding carriage, exchange of the mandrels or tailstock centres being performed when the grinding spindle or tailstock respectively is rotated from the working position.
11. Grinding machine according to any of claims 1 to 4, wherein the internal-grinding carriage carries a single device for holding either the tailstock centre or a grinding mandrel.

a k
12. Grinding machine according to any of claims 1 to 7, wherein the grinding device is a grinding spindle and the tailstock centre is held in a tailstock mounted on the internal-grinding carriage parallel and adjacent to the spindle.
13. Grinding machine according to claim 11 or 12 and having automatic change of grinding mandrels and tailstock centres from a tool disc mounted on a magazine so as to be disposed to the left of the internal grinding carriage.
14. A cylindrical grinding machine according to claim 6, wherein the tailstock comprises a body inside which there is disposed a poppet sleeve, in the front end of which is machined a cone for automatic fastening of the tailstock centre, and in the rear end of which is fixed a double-acting cylinder, in the centre hole of the poppet sleeve there is inserted a rod, to the forward end of which there is fastened a sleeve containing balls, and on the rear end of which are mounted disc -springs limited by a regulable nut, and to the rear end of the body there is mounted a single acting cylinder, a spring being disposed between the cylinders.
15. Grinding machine according to any preceding claim, wherein the motors for the left and right carriages are synchronised.
16. Grinding machine according to any preceding claim, wherein the grinding machine is numerically controlled.
17. Grinding machine substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

ublished 19B13 atThe Pate.= Offif3e. State House. 6671 High Hlborn. London VIC1R 4TP- Further copies may be obtained from The Patent 0Mce, SIes Brarch. St Mary Cray. OrDington, 1xent BR5,MD Trinted kv Mjl,,1,e_x. ech:,jcries ltd. St 1,1.ra-.y, Cray, Kent. Con. 1,87.