GB2060445A

GB2060445A - Spindle Drives

Info

Publication number: GB2060445A
Application number: GB8032636A
Authority: GB
Original assignee: Friedrich Deckel AG
Current assignee: Friedrich Deckel AG
Priority date: 1979-10-12
Filing date: 1980-10-09
Publication date: 1981-05-07
Also published as: ES495291A0; IT1188954B; GB2060445B; IT8049812A1; JPS5697658A; FR2467049A1; ES8105609A1; DE2941500A1; ATA469780A; IT8049812A0

Abstract

A spindle drive for displacing a machine part on a frame, such as a machine slide 2 on the bed 4 of a machine tool, comprises a threaded spindle 10 cooperating with a spindle nut 6 and a drive motor 16 connected to the spindle (or the nut). For manual displacement of the machine slide 2, a handwheel 24 is directly connected to the drive shaft 22 of the motor 16. Alternatively, the handwheel can be connected indirectly to the drive shaft 22 such as by reduction gears 14. <IMAGE>

Description

SPECIFICATION Spindle Drive for Displacing a Machine Part on a Frame The present invention relates to a spindle drive for displacing a machine part on a frame, for example a machine slide on the bed of a machine tool.

In the majority of cases, a drive motor is used for displacing the machine part, such as in all controlled machining operations, in positioning at rapid traverse rates etc. However, there are cases in which a manual drive is preferred, particularly in the production of complicated one-off parts, in precision positioning or in copying curves that cannot be programmed.

A spindle drive is known wherein a drive motor and a handwheel are arranged at the two opposite ends of a threaded spindle (e.g. Deckel FP 2). Between the relatively high-speed motor and the threaded spindle are reduction gears which reduce the motor speed to a lower, spindle speed. In this connection it might be mentioned that, on the one hand, the speed range of motors, particularly electrical motors, cannot be freely selected because of the structural dimensions, torque during slow rotation, etc., and that, on the other hand, the speed range of threaded spindles must also be kept within relatively narrow limits for reasons of mounting, possible thread pitch and the efficiency associated therewith, so that reductions to lower speeds cannot be avoided as a rule.Reduction gears are likewise provided between the handwheel and the threaded spindle so as to enable sensitive manual setting requiring little force to be carried out.

When moving the machine part by hand and in order not to have to turn the motor, which is connected to the other end of the spindle and is very difficult to accelerate and slow down because of its being geared to a higher speed, a clutch is also provided between the motor gear and the spindle, so that the gear and the motor can be disengaged during manual operation.

As a whole, this spindle drive is very complicated and expensive in design and construction. It also involves additional cost for controlling it or additional attention on the part of the operator for disengaging the motor during each manual operation and re-engaging it for powered operation.

The object of the present invention is to provide a spindle drive which is simple to construct and handle.

According to the invention, this object is achieved by a spindle drive for displacing a machine part on a frame, for example a machine slide on the bed of a machine tool, and comprising a threaded spindle co-operating with a spindle nut, a drive motor connected to the spindle nut or the spindle for powered displacement of the machine part, and a handwheel directly or indirectly connected to the drive shaft of the motor for manual displacement of the machine part.

Accordingly, the handwheel can be arranged at that end of the spindle (or of the spindle nut in the case where the latter is driven) that faces the motor, and is connected to the shaft of the motor.

The motor is also rotated when manual drive takes place. However, since no stepping up to a higher speed takes place between the handwheel and the motor, the above-described.

disadvantages associated therewith do not occur.

The additional gears provided between the handwheel and the spindle in the known arrangement can be dispensed with as can the clutch and the associated actuating means provided between the motor gears and the spindle, since in a drive in accordance with the invention, the drive path from the motor to the spindle and from the handwheel to the spindle is the same.

This results in an arrangement, which is simpler to construct and handle as compared with the known design.

In one form of the invention, the drive shaft of the motor is extended beyond the motor housing at its non-driving end and the handwheel is provided directly on the extended shaft. The handwheel can be designed in the usual way as what is called a safety handwheel which is automatically disengaged from the shaft when the machine operates under power. This arrangement calls for no additional cost in construction apart from that involved in the provision of the extended motor shaft and therefore represents a particularly simple and economical solution.

If, as is generally the case for the reasons mentioned above, reduction gears are provided between the motor and the spindle nut or the spindle, the handwheel can be arranged on any shaft in driving connection with the reduction gears. This shaft may, for example, be one of the gear shafts themselves which are present in any case.

Some embodiments of the invention will now be described in detail with reference to the accompanying diagrammatic drawings, in which: Figure 1 illustrates a known form of spindle drive for a machine-tool bench; Figure 2 illustrates an embodiment of a spindle drive in accordance with the invention; Figure 3 shows a further embodiment of the invention and Figures 4 and 5 illustrate respective modifications to the embodiment of Figure 3.

Figure 1 shows an existing spindle drive arrangement for displacing a workpiece bench 2 on the bed of a machine tool. The workpiece bench 2 is displaceably mounted on guide tracks 4 of the machine bed, not illustrated. A spindle nut 6 is rigidly connected to the workpiece bench 2 and co-operates with a threaded spindle 10 which is non-displaceably mounted in the machine bed by way of bearings 8, but is rotatable. An electic motor 16 is connected through reduction gears 14 and a clutch 12 to the right-hand end of the screwed spindle as seen in Figure 1. In normal operations, the motor 16 drives the spindle 10 by way of the reduction gears 14, so that, depending upon the direction in which the motor 16 is turning, the bench 2 is displaced to the right or to the left.For manual operation, a handwheel 20 is connected to the left-hand end of the spindle by way of a reduction gear 18. The clutch 12 is disengaged during manual operation to avoid the need for also turning the motor at higher speed through the gears 14.

Figure 2 shows an embodiment of a spindle drive according to the invention which is arranged similar to the arrangement illustrated in Figure 1; in the two Figures, like parts are designated by the same reference numerals. In contrast to the Figure 1 arrangement, in Figure 2 the drive shaft 22 of the electric motor 1 6 is extended at the right-hand non-driving end. Fitted on the extended shaft 22 is a standard handwheel 24 which therefore does not require to be described in detail; this handwheel is designed as what is called a safety handwheel so that it is automatically disengaged when the machine operates under power. During manual operation, the motor is turned, this being possible because the handwheel 24 can be directly connected to the motor shaft 22 without difficulty.Since the drive of the spindle 10 is by way of the shaft 22 and the gears 14 in each case, i.e. in powered and manual operation, a clutch is not necessary between the gear 14 and the spindle 10.

Furthermore there is no gears 18 at the left-hand end of the spindle since the gears 14 provide the necessary reduction both in powered operation and manual operation.

Figure 3 illustrates another embodiment of the invention in which the spindle 30 is mounted in the workpiece bench 32, so that the spindle as well as the entire spindle drive move with the bench. The spindle nut 34 is rigidly mounted in the machine bed. The reduction gears 36 are bevel gears so that the shaft 38 of the motor 40 is at right angles to the axis of the spindle 30. In this case too, the handwheel 42 is arranged on the extension of the shaft 38.

Figure 4 shows a modification wherein the handwheel 50 is not directly connected to the shaft 52 of the motor 54, but indirectly by way of a shaft 55 and a bevel gear 56 which meshes with the bevel gear 58 of the reduction gears 60.

The spindle 62 is shown only in part.

Finally, Figure 5 illustrates a modification wherein the motor 70 is again connected to the spindle 74 by way of bevel gears 72. The shaft 76 is extended to a sufficient extent at the drive side of the motor 70 so that the handwheel 78 can be mounted thereon.

The above embodiments of the invention are illustrated only by way of example. The invention can readily include other embodiments having a different arrangement of the handwheel. In each case, however, the motor drive is by way of the reduction gears which are always present for operating the machine under power, so that separate reduction gears for the manual drive can be omitted.

Claims

1. A spindle drive for displacing a machine part on a frame, for example a machine slide on the bed of a machine tool, and comprising a threaded spindle co-operating with a spindle nut, a drive motor connected to the spindle nut or the spindle for powered displacement of the machine part, and a handwheel directly or indirectly connected to the drive shaft of the motor for manual displacement of the machine part.

2. A spindle drive according to Claim 1, wherein the drive shaft of the motor is extended at its non-driving end, and the handwheel is arranged directly on this extended shaft.

3. A spindle drive according to Claim 1, comprising reduction gears arranged between the motor and the spindle nut or the threaded spindle, wherein the handwheel is arranged on a shaft in driving connection with the reduction gears.

4. A spindle drive according to Claim 3, wherein the handwheel is arranged directly on the shaft of one of the gears.

5. A spindle drive for displacing a machine part on a frame, substantially as hereinbefore described with reference to Figures 2 to 5 of the accompanying drawings.