Gear cutting machine and method for machining gear teeth

Abstract

The invention concerns a gear-cutting machine for the machining of gear teeth with a gear-cutting tool driven in rotary movement about its tool axis, further with an assembly that includes a tool holder for the gear-cutting tool and is rotatably mounted on a carrier, allowing the tool axis to be set in a desired orientation, with an actuator device through which the assembly can be set to a desired angular position, and with a locking device that allows the assembly to be secured against being dislodged from the set angular position. According to the invention, a protruding arm that is a functional element of the actuator device is coupled to the assembly through a non-rotatable connection.

Claims

1. Gear-cutting machine for the machining of gear teeth with a gear-cutting tool driven in rotary movement about its tool axis, comprising an assembly (60) that includes a tool holder for the gear-cutting tool and is rotatably mounted on a carrier (50, 40), allowing the tool axis (Y) to be set in a desired orientation, an actuator device through which the assembly can be set to a desired angular position, and a locking device that allows the assembly to be secured against being dislodged from a set angular position, characterized by a protruding arm (70) that is coupled to the assembly through a non-rotatable connection and is a functional element of the actuator device.

2. Gear-cutting machine according to claim 1, wherein the carrier is a first linear carriage (50) having a drive source.

3. Gear-cutting machine according to claim 2, wherein the drive source of the first linear carriage in a first operating position of the gear-cutting machine is a functional element of the actuator device.

4. Gear-cutting machine according to claim 1 wherein the actuator device comprises a counter bearing (82, 80) cooperating with the end of the protruding arm on the opposite side of the non-rotating connection.

5. Gear-cutting machine according to claim 4, wherein the cooperation takes place in the form of a rolling support.

6. Gear-cutting machine according to claim 3 wherein the drive source of the first linear carriage in a second operating position of the gear-cutting machine is not a functional element of the actuator device.

7. Gear-cutting machine according to claim 6 wherein a transition between the first and the second operating position can be effected by a relative movement between the first linear carriage (50) and a counter bearing (82, 80), wherein said relative movement runs transverse to the movement direction of the first linear carriage.

8. Gear-cutting machine according to claim 2 wherein the first linear carriage (50) is supported by a second linear carriage (40).

9. Gear-cutting machine according to claim 7 wherein the relative movement can be effected by a movement of a second linear carriage (40) that supports the first linear carriage (50).

10. Gear-cutting machine according to claim 1 wherein the angular positions that can be set for the assembly cover a range of at least 90 and wherein the orientation that can be set for the tool axis to cover a range of at least 45 relative to a horizontal orientation.

11. Gear-cutting machine according to claim 1 wherein the gear-cutting machine is configured as a hobbing machine and can accept a hob as gear-cutting tool.

12. Method for the machining of gear teeth with a machining tool driven in rotary movement about its tool axis and at a prescribed orientation of the tool axis, wherein as a first step, the tool axis is set to, and locked at, the prescribed orientation, and next prior to and/or during the machining, a relative movement is executed between the tooth-cutting tool and the toothed workpiece, characterized in that the setting of the orientation of the tool axis and the execution of the relative movement are actuated by the same drive mechanism.

13. Gear-cutting machine according to claim 2 wherein said first linear carriage is a vertical carriage.

14. Gear-cutting machine according to claim 8 wherein said second linear carriage is a horizontal carriage.

Description

(1) Further distinguishing features, details and advantages of the invention will become evident from the following description of the attached drawings, wherein

(2) FIGS. 1a, b, c schematically illustrate the underlying principle of the invention, and

(3) FIG. 2 represents a sectional view of a support arrangement for a tool holder configured in accordance with the invention.

(4) FIG. 1 schematically illustrates a cross-slide carriage arrangement composed of a horizontal carriage 40 that is movable in the X-direction (perpendicular to the plane of the drawing) and a vertical carriage 50 that is arranged on a side of the horizontal carriage 40 facing towards the workpiece spindle (the latter not being shown in the drawing). The vertical carriage is movable vertically, i.e. in the Z-direction.

(5) The vertical carriage 50 rotatably supports an assembly 60 on which a hobbing tool head (not shown in the drawing) is arranged in the conventional manner by way of a further shift carriage. The orientation of the rotary axis of a hob that is held by the hobbing tool head in relation to the plane extending orthogonal to the movement axis X of the horizontal carriage 40 can be changed only through a rotation of the assembly 60. The hob axis may be oriented for example parallel to the direction in which a protruding arm 70 juts out of the assembly. FIG. 1a shows a situation where this direction Y runs horizontal and perpendicular to the movement axis X of the horizontal carriage 40.

(6) To set the angular position of the tool axis, i.e. the orientation of the direction Y in the plane extending orthogonal to the movement direction X, the horizontal carriage 40 is moved into a position in which the protruding arm 70 is positioned above a post 80. Preferably, the vertical carriage 50 is moved to a position where the protruding arm 70 near its free end comes to rest on a ball joint arranged at the upper end of the post 80. All of this activity takes place while the assembly 60 is still locked in its current angular position by a locking device (not shown) that is available to secure the hobbing tool head in the conventional manner of the state of the art. Alternatively, it is also conceivable that the post is arranged on the horizontal carriage and is movable relative to the latter. In that case, the setting of the orientation of the tool axis can be performed in any position of the horizontal carriage.

(7) When the protruding arm has come to rest on the ball joint, for example in the angular position where the tool axis is horizontal as shown in FIG. 1, the locked condition is released.

(8) Next, the tool axis can be turned clockwise (starting from the position shown in FIG. 1a) by moving the vertical carriage in the upward direction as shown in FIG. 1c, or counterclockwise by moving the vertical carriage 50 in the downward direction as shown in FIG. 1b.

(9) As soon as the desired angular position of the assembly 60 has been attained and a signal to this effect has been received by a controller device of the hobbing machine from a sensor (not shown) detecting the angular position of the assembly 60, the locking device is activated and the assembly 60 is locked into the set angular position. In this first operating position, which in the illustrated example is determined by the travel position of the horizontal carriage 40 allowing the protruding arm 70 and the post 80 to cooperate with each other, the setting of the angular position of the assembly 60 can thus be made preferably by way of a CNC-based actuation of the vertical carriage 50.

(10) For the machining of the workpiece in a second operating position of the gear-cutting machine, the horizontal carriage 40 is moved from the travel position just described in the direction towards the workpiece spindle, so that the vertical carriage 50 in this second operating position is unimpeded by the post 80 and free to move along its travel axis Z, i.e. able to perform the standard infeed movement parallel to the workpiece axis for the hobbing operation.

(11) It is evident that with the use of the protruding arm 70, it is no longer necessary to couple the assembly 60 to a direct drive or to a gear train that is connected to its own drive source as normally realized in these machines through driven rotating supports.

(12) The invention is not limited to the configuration of the gear-cutting machine described through the illustrated embodiment. For example the post 80 could also be designed without the ball joint 82, or the post 80 itself could be designed to be movable, although this would require an additional drive mechanism. In the latter case, the post 80 could for example be designed to be collapsible in the manner of a telescope, or to be fully retractable into a machine bed (not shown) in the second operating position.

(13) Also, in the first operating position, the movement of the vertical carriage could be transmitted in a different way to the assembly, for example through a gear/rack arrangement. For the change from the first to the second operating position, the gear engagement would have to be uncoupled. The disengagement could be performed manually, for example with an actuating lever, or automatically by coupling the disengagement to the movement of the horizontal carriage 40, if the use of an additional drive mechanism is to be avoided.

(14) FIG. 2 shows a rotatably supported part 1 in a sectional view. The free side 1b serves in the normal way to fasten, for example, a hobbing tool head (not shown) with tool spindle.

(15) The rotary support of part 1 in a non-rotating part 2 is not compromised in regard to its structural strength by the presence of a drive mechanism or a transmission coupled to a drive mechanism. During the machining operation, a locking device configured as a diaphragm spring 4 ensures that part 1 can no longer rotate against part 2 (second operating position), as part 1 in the area 12 is seated on part 2 and pressed against the latter. When part 1 is moved relative to part 2 in the axial direction (X), this friction-based connection is released and part 1 can be turned relative to part 2 into a desired angular position as described in the context of FIG. 1.

(16) Part 2 in this example is part of a vertical carriage (movement direction Z perpendicular to the drawing plane of FIG. 2) which, in turn, is movably supported on the radial carriage 3 (movement direction X), consistent with conventional practice. A sensor 5 registers the angular position of part 1 relative to part 2 and transmits this information to a controller (not shown) of the machine.

(17) Since the arrangement for supporting part 1 in part 2 no longer has to leave room for a drive mechanism or the connection to a drive by means of a transmission, for example a worm-gear transmission, the support can be designed with significantly greater structural rigidity, which is a primary advantage of the invention. As a further advantage, the invention offers the aforementioned possibility that the drive mechanism which in this embodiment serves to actuate the vertical carriage can also be used to change the angular position of part 1 relative to part 2, which saves an entire drive mechanism.

(18) The invention is not limited to the examples of embodiments presented in the description of the drawings. Rather, the features of the foregoing description as well as of the following claims can be essential, individually or in combination, for the realization of the invention in its different embodiments.