GB1581409A

GB1581409A - Brake device for a rotatable spindle

Info

Publication number: GB1581409A
Application number: GB24335/78A
Authority: GB
Original assignee: Gildemeister AG
Current assignee: DMG Mori AG
Priority date: 1977-06-08
Filing date: 1978-05-30
Publication date: 1980-12-10
Also published as: IT7812652A0; DE2725798B1; DE2725798C2; CH628716A5; IT1103806B

Abstract

Arranged on the spindle sleeve (1) of a workpiece spindle, there is, in addition to a clutch (2), first of all a multi-disc brake (5), the discs of which are seated fixedly in terms of rotation in alternating sequence on the spindle sleeve (1), on the one hand, and in the housing (6) on the other hand. Arranged in series with the multi-disc brake (5) is a cone brake, the ring (8) provided with the external taper being supported on a spindle nut (7) and the ring (9) provided with the internal taper being supported on the outermost disc of the multi-disc brake (5). The combination of these two brakes allows the spindle to be held fast in a play-free manner without a radial force being introduced into the spindle. If a spring is arranged between the multi-disc brake and the cone brake, then, initially, only the multi-disc brake (5) is actuated and the cone brake (8, 9) is only actuated in the presence of an increased pressing force. <IMAGE>

Description

(54) BRAKE DEVICE FOR A ROTATABLE SPINDLE (71) We, GILDEMEISTER AKTEINGESELLSCHAFT, a Company organised under the laws of the Federal Republic of Germany, of : Am Hauptbahnhof, 4800 Bielefeld 1, Federal Republic of Germany, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a brake device for a rotatable spindle such as a workpiece spindle of a multiple-spindle rotary automatic chucking machine.

It is known to bring a workpiece spindle of a multiple-spindle rotary automatic chucking machine to a stand-still with a multiple-disc brake after releasing the drive clutch. The multiple-disc brake has the advantage that it can provide a great braking effect and bring the spindle quickly to a standstill. Since the discs of the multipledisc brake are secured against rotation.

partly on the spindle and partly in a housing, by splines or the like. while cams of the splines, however, must be displaceable in a longitudinal direction in grooves, the spindle can still move, for example by the action of the machining forces on the workpiece held in the spindle. The play in gears of the outer and the inner discs often leads. during machining of the workpiece on the braked spindle, to undesirable vibrations in the chucking machine and thereby to chatter marks and inaccuracies on the workpiece.

In order to avoid such drawbacks. a locking means has already been proposed which has a locking element which may be forced against a counterpart secured to the workpiece spindle. However. this locking means has in turn the disadvantages that it is not possible to achieve an exactly determined contact pressure by the locking means due to the flexibility of its transmission lever and the play in its bearings and that the spindle is deformed by the strong radial force acting upon it.

There is thus a need for a brake device which can lock, substantiall free of play, a rotatable spindle, with a high locking moment and substantially without introducing radial force into the spindle.

According to the present invention there is provided a brake device for a rotatable spindle such as a workpiece spindle of a multiple-spindle rotary automatic chucking machine. including a multiple-disc brake, and a conical brake disposed in line with the multiple-disc brake.

The brake device may be arranged in such a way that the frictional braking work is predominantly undertaken by the multipledisk brake and the conical brake only becomes effective when a predetermined brake operating frame is exceeded.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example to the accompanying single Figure drawing which shows a longitudinal section of a sleeve secured to a workpiece spindle of a multiple-spindle rotary automatic chucking machine, this sleeve having a drive clutch and a brake device according to the invention.

As shown in the drawing. on the righthand side of sleeve 1 is arranged a clutch 2, which is actuated in known manner by a lever 4 via a bush 3 arranged on the sleeve 1 for longitudinal movement and which creates or releases a force-locking connection between the spindle and its drive element.

The bush 3 at the same time actuates a brake device of the invention located on the left-hand side of the sleeve 1.

This brake device includes a multiple-disc brake 5, alternate discs of which are secured in known manner against relative rotation with respect to the spindle sleeve 1 and a housing 6.

The device also includes a conical brake located between the multiple-disc brake 5 and a spindle nut 7 clamped onto the sleeve 1, which nut serves to adjust axial play of the multiple-disc brake 5. The conical brake has a ring 8 provided with an outer conical portion, which may be longitudinally displaced to a limited extent, but which is secured is secured against rotation and supported by the nut 7. and an outer ring 9 provided with an inner conical portion. A plane surface of the ring 9 directed away from the ring 8 is supported by the outer disc of the multiple-disc brake 5 facing the ring 9. In order to achieve a certain flexibility, the brake outer ring 9 may be provided at its outer region with radial slots 91 disposed in even distribution around the periphery. Furthermore, it is possible and in many cases advantages to locate springs between the spindle nut 7 and the outer brake ring 9, which raise the brake ring 9 from the inner brake ring 8 when the brake is released and force the brake ring 9 against the outer disc of the multiple-disc brake 5 facing the ring 9. These springs support the outer ring 9 relative to the nut 7 or the housing 6 so that the conical brake only becomes effective after the multiple-disc brake 5.

The brake device according to the invention, operates in the following manner: By displacement to the left of the bush 3 the drive clutch 2 is released and the spindle is thus disconnected from the drive. By further displacing the bush 3 to the left, pressure is exerted by a lever 10, indicated bv a dot-dash line. on a disc li abutting the outer disc of the brake 5, so that the inner and outer discs of the brake 5 are compressed. If the outer ring 9 of the conical brake is not acted upon by the above-mentioned springs, the brake ring 9 is simultaneously pressed against the brake ring 8 and the residual energy of the spindle is thereby nullified by the friction between the discs and by the friction arising between the conical portions of the rings 8 and 9.

If springs are disposed between the shaft nut 7 or the housing 6 and the brake ring 9, then initially only the multiple-disc brake 5 operates. Only under further increasing contact pressure do the conical portions of the brake rings 8 and 9 come into contact with each other so that the spindle is held free from play. The outer brake ring 9 is thereby expanded and supported by the housing 6. This expansion is aided by the radial slots 91 provided in the brake ring 9.

WHAT WE CLAIM IS: l. A brake device for a rotatable spindle such as a workpiece spindle of a multiplespindle rotary automatic chucking machine, including a multiple-disc brake. and a conical brake disposed in line with the multipledisc brake.

2. A brake device according to claim 1, wherein the multiple-disc brake and the conical brake are actuated by common transmission elements.

3. A brake device according to claim 1 or claim 2, wherein an outer ring of the conical brake, having a plane surface abutting an outer disc of the multiple-disc brake is supported by springs relative to a spindle nut or a housing, so that the conical brake only becomes effective after the multipledisc brake.

4. A brake device according to claim 3, wherein the outer ring of the conical brake has an inner conical portion and is provided with radial slots on its periphery.

5. A brake device for a rotatable spindle, substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

The device also includes a conical brake located between the multiple-disc brake 5 and a spindle nut 7 clamped onto the sleeve 1, which nut serves to adjust axial play of the multiple-disc brake 5. The conical brake has a ring 8 provided with an outer conical portion, which may be longitudinally displaced to a limited extent, but which is secured is secured against rotation and supported by the nut 7. and an outer ring 9 provided with an inner conical portion. A plane surface of the ring 9 directed away from the ring 8 is supported by the outer disc of the multiple-disc brake 5 facing the ring 9. In order to achieve a certain flexibility, the brake outer ring 9 may be provided at its outer region with radial slots 91 disposed in even distribution around the periphery. Furthermore, it is possible and in many cases advantages to locate springs between the spindle nut 7 and the outer brake ring 9, which raise the brake ring 9 from the inner brake ring 8 when the brake is released and force the brake ring 9 against the outer disc of the multiple-disc brake 5 facing the ring 9. These springs support the outer ring 9 relative to the nut 7 or the housing 6 so that the conical brake only becomes effective after the multiple-disc brake 5.

The brake device according to the invention, operates in the following manner: By displacement to the left of the bush 3 the drive clutch 2 is released and the spindle is thus disconnected from the drive. By further displacing the bush 3 to the left, pressure is exerted by a lever 10, indicated bv a dot-dash line. on a disc li abutting the outer disc of the brake 5, so that the inner and outer discs of the brake 5 are compressed. If the outer ring 9 of the conical brake is not acted upon by the above-mentioned springs, the brake ring 9 is simultaneously pressed against the brake ring 8 and the residual energy of the spindle is thereby nullified by the friction between the discs and by the friction arising between the conical portions of the rings 8 and 9.

If springs are disposed between the shaft nut 7 or the housing 6 and the brake ring 9, then initially only the multiple-disc brake 5 operates. Only under further increasing contact pressure do the conical portions of the brake rings 8 and 9 come into contact with each other so that the spindle is held free from play. The outer brake ring 9 is thereby expanded and supported by the housing 6. This expansion is aided by the radial slots 91 provided in the brake ring 9.

WHAT WE CLAIM IS: l. A brake device for a rotatable spindle such as a workpiece spindle of a multiplespindle rotary automatic chucking machine, including a multiple-disc brake. and a conical brake disposed in line with the multipledisc brake.
2. A brake device according to claim 1, wherein the multiple-disc brake and the conical brake are actuated by common transmission elements.
3. A brake device according to claim 1 or claim 2, wherein an outer ring of the conical brake, having a plane surface abutting an outer disc of the multiple-disc brake is supported by springs relative to a spindle nut or a housing, so that the conical brake only becomes effective after the multipledisc brake.
4. A brake device according to claim 3, wherein the outer ring of the conical brake has an inner conical portion and is provided with radial slots on its periphery.
5. A brake device for a rotatable spindle, substantially as hereinbefore described with reference to the accompanying drawing.