LU93127B1 - Adapter for torque transmission between the drive shaft and output shaft of a machine tool, in particular an electrically operated milling machine - Google Patents

Abstract

An adapter (10) for torque transmission between the drive shaft (40) and output shaft (46) of a machine tool (28), in particular an electrically operated milling machine, comprises a base body (12) having a drive shaft side end portion (16), a output shaft side end portion (18) and with at least two pins (20) projecting beyond the base body (12) in the axial direction for receiving a torque output by the drive shaft (40) in an operational state of the machine tool (28). An internal thread (22) of the adapter (10) arranged along the center axis (14) serves for the machine tool (28) to be in operative condition for connection to the output shaft (46). The output shaft-side end portion (18) has at least one contact surface (26) which is provided to exert a mechanical bias in the axial direction when one of the roller bearings (56) of the machine tool (28) is ready for operation. A machine tool (28) comprises a housing (30), a housing (30) fixedly arranged drive (38) with drive shaft (40), an output shaft (46), one between the drive shaft (40) and the output shaft (46) such adapter (10), a first roller bearing (56) and a second spaced apart in the axial direction of the second rolling bearing (62) for supporting the output shaft (46) on the housing (30). In the ready state of the machine tool (28) are the first roller bearing (56) by the contact surface (26) of the adapter (10) and the second roller bearing (62) by an interaction of the adapter (10) and the output shaft (46) with a defined mechanical bias applied in the axial direction.

Description

Adapter for torque transmission between drive shaft and output shaft of a machine tool, in particular an electrically operated Fräs

description

Technical area

The present invention relates to an adapter for torque transmission between the drive shaft and output shaft of a machine tool, in particular an electrically operated Feinfrâse, and a machine tool with such an adapter.

State of the art

Conventionally, belt drives are used in machine tools and in particular in fine milling to compensate for an axial, radial and / or angular offset between a drive shaft of an engine and an output shaft of the machine tool; if necessary, a speed can be preselected with the belt drive. As a result, both drive shaft bearings and output shaft bearings are loaded with a mechanical base load in the transverse direction, which must be taken into account in a calculation of the bearing numbers of the bearings, and which generally has a negative effect on the load ratings.

Object of the invention

It is a particular object of the invention to simplify the transmission of torque between a drive shaft and an output shaft of the machine tool in a machine tool.

Disclosure of the invention

The invention relates to an adapter for torque transmission between the drive shaft and output shaft (otherwise: working shaft) of a machine tool.

The adapter comprises a substantially cylindrical base body having a center axis, a drive shaft side end portion, and an output shaft side end portion. Furthermore, the adapter comprises at least two pins arranged on the drive shaft-side end part and projecting beyond the base body in the axial direction for receiving a torque output by the drive shaft in an operational state of the machine tool.

The adapter also has an inner thread arranged along the central axis, which serves for the mechanical connection to the output shaft in the operational state of the machine tool.

The output shaft-side end part has at least one contact surface, which is provided to exert a mechanical bias in the axial direction in the ready state on one of the rolling bearings of the machine tool.

An "axial direction" should be understood in this context, in particular a direction which is arranged parallel to the central axis.

In this context, a "drive shaft-side end part" is to be understood in particular to mean an end part which faces the drive shaft when the machine tool is ready for operation.

Under a "output shaft side end portion" soli in this context, in particular an end part are understood, which faces away in the ready state of the machine tool of the drive shaft.

In this context, the term "intended" is to be understood in particular to mean specially designed, equipped or arranged.

The proposed adapter can replace the belt drive used in conventional machine tools for the transmission of torque from the drive shaft to the output shaft. In a suitable embodiment, an axial, radial and / or angular offset between the drive shaft and the output shaft and an associated mechanical base load in the transverse direction can be advantageously avoided. Furthermore, a torque transmission can be made possible with a small number of components and in a compact design. In addition, in a suitable embodiment, an improved synchronization of the mechanical system formed by the drive shaft and output shaft can be achieved by reducing or avoiding tolerance-chain-related running noise.

The proposed simultaneous use of the adapter for torque transmission and the defined bias of the bearing of the output shaft can also be advantageous to reduce the tolerance chain to a junction.

In particular, the mechanical connection between the internal thread of the adapter and the output shaft serves to transmit the torque received by the adapter from the drive shaft to the output shaft.

The machine tool can be designed as an electrically operated machine tool, in particular as an electrically operated fine milling machine.

Preferably, the base body and the pins are made in one piece. In this context, the term "integral" should be understood in particular to be made from solid or cohesively connected, as understood, for example, by a welding process and / or gluing process, and, particularly advantageously, molded, for example, by manufacture from a cast and / or by manufacture in a single or multi-component injection molding process.

As a result, a particularly high mechanical strength between the base body and the pin can be achieved. Furthermore, it can be simplified by a Hersteliung the adapter.

In addition, it is proposed that the cross-sectional areas of the pins have a triangular shape, wherein one of the corners of the triangular shape facing the central axis. In this way, laterally arranged surfaces can easily be provided for receiving the torque provided via the drive shaft, whereby these lateral surfaces of the pins are loaded with a low surface pressure. The term "triangular shape" should in particular also include forms in which at least one of the corners of the triangular shape is not completely formed.

Particularly advantageously, at least one side of the triangular shape, which abuts against the center axis facing corner, i. one of the laterally arranged surfaces of a pin, a concave curvature on. In this way, during the recording of the torque provided via the drive shaft, a centering of the attacking forces can be achieved.

Preferably, the adapter may comprise an even number of pins arranged in pairs opposite each other with respect to the central axis. This advantageously allows a uniform spatial distribution of the forces acting on the provision of the torque provided. The formation of pairs of forces for transmitting the torque can also be avoided in particular a stress of the pins on shear and bending.

In a further aspect of the invention, a machine tool is proposed. The machine tool comprises a housing, a fixed drive in the housing with a drive shaft and an output shaft. The machine tool further includes an embodiment of the disclosed adapter disposed between the drive shaft and the output shaft.

In addition, the machine tool has a first rolling bearing and a second rolling bearing spaced apart in the axial direction of the first roller bearing for supporting the output shaft. Outer rings of the first rolling bearing and the second rolling bearing are arranged fixed in position in the axial direction on the housing. The terms "first", "second", etc. are used in the present application for the purpose of distinction only. A rank order between the rolling bearings can not be derived by using these terms.

In the ready state of the machine tool, the first roller bearing are acted upon at least by the contact surface of the adapter and the second roller bearing at least by a cooperation of the adapter and the output shaft with a defined mechanical bias in the axial direction.

Advantageously, in a suitable embodiment, the tolerance chain of the arrangement can be reduced by one connection point, since the torque-transmitting adapter simultaneously serves for the defined preload of the bearings of the output shaft. As a result, in addition to the simplification of the torque transmission, an improvement in the running properties of the machine tool can be achieved. Furthermore, the advantages mentioned in connection with the disclosure of the proposed adapter are fully applicable to the machine tool.

The machine tool preferably has a tool receptacle which can be fixedly attached to one end of the output shaft for receiving an insertion tool.

Particularly preferably, the drive shaft, the central axis of the base body of the adapter and the output shaft are arranged parallel to each other in an operative state of the machine tool.

In preferred embodiments, the machine tool can be designed as an electrically operated machine tool, wherein the drive fixedly arranged in the housing is formed by an electric motor. In particular, the machine tool can be designed as an electrically operated fine milling machine.

Particularly preferably, the fixedly arranged in the housing of the machine tool drive is formed by an electric motor which is designed as an electronically commutated DC motor. In this way, the aforementioned advantages of the adapter used in the machine tool can be combined with a compact design of an electromotive drive.

drawings

Further advantages emerge from the following description of the drawing. In the drawing, an embodiment of the invention is shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

It shows:

1 shows an adapter according to the invention in several views,

2 shows a schematic side view of an arrangement of the adapter according to FIG. 1 in a drive train of an electrically operated machine tool, FIG.

Fig. 3 is a schematic, quarter-quarter sectional view of the machine tool according to FIG. 2, and

4 shows a perspective view of a detail of the drive train of the electrically operated machine tool according to FIG. 3 in an exploded view.

Description of the embodiments

Fig. 1 shows an adapter 10 according to the invention in a sectional side view (left), in a front view (center) and in a non-cut side view (right). As will be described below, the adapter 10 serves to transmit torque between the drive shaft and the output shaft of a machine tool.

The adapter 10 comprises a substantially cylindrical base body 12 having a central axis 14, a drive shaft side end portion 16 and a output shaft side end portion 18. In an operative state of the machine tool, the drive shaft side end portion 16 faces the drive shaft and the output shaft side end portion 18 of the drive shaft facing away.

Furthermore, the adapter 10 has an even number of two pins 20 arranged on the drive shaft-side end part 16. The pins 20 protrude in the direction of the central axis 14 beyond the base body 12. The cross-sectional areas of the pins 20 each have a triangular shape, in particular the shape of an isosceles triangle. In each case one of the corners of the triangular shapes faces the central axis 14. The two pins 20 are arranged opposite one another with respect to the central axis 14.

The base body 12 and the pins 20 are made in one piece and manufactured by means of an aluminum die-casting process.

In an alternative embodiment, the base body 12 and the pins 20 may be machined from the solid, for example, a cylindrical aluminum alloy semi-finished product. In another alternative embodiment, the adapter 10 may be made of a high performance plastic, such as polyetherimide (PEI). The high-performance plastic can hereby be reinforced by fibers, for example by gias or carbon fibers.

Although the adapter 10 has two pins 20 in this particular embodiment, in alternative embodiments also a different odd or even number of pins 20 are provided. If the adapter 10 is equipped with an odd number of pins 20, they may preferably be arranged at uniform angular intervals in the azimuthal direction about the central axis 14.

Those sides of the respective triangular shapes, which abut against the corner facing the central axis 14, have a constant concave curvature in the form of a circular arc. A corner opposite to this corner of each of the two triangular shapes has a constant convex curvature in the form of a circular arc whose radius coincides with a radius of the cylindrical base body 12. The base of each of the two triangular shapes is aligned with a circumferential line of the cylindrical base body 12.

In addition, the adapter 10 is provided with an internal thread 22 which is formed as a central, continuous thread along the central axis 14. As will be explained below, the internal thread 22 is in the ready state of the machine tool for mechanical connection to the output shaft.

At the output shaft side end portion 18, a central, cylindrical recess 24 is mounted within the cylindrical base body 12 through which an accessible from the output shaft side end portion 18 receptacle is formed. The receptacle is intended to receive a part of the output shaft of the machine tool in an operational state.

The base body 12 forms at a drive-shaft-side end of the recess 24 a stop 54 for the defined definition of an axial position of the output shaft in an operative state of the machine tool.

In addition, the adapter 10 has a arranged on the output shaft side end portion 18 bearing surface 26 in the form of a circular ring. The contact surface 26 is intended, in the operational state of the machine tool with a corresponding surface of a rolling bearing of the machine tool for performing a mechanical bias in the axial direction in effective contact with, as described below.

The use of the adapter 10 in a machine tool will be explained below with reference to FIGS. 2 to 4. FIG. 2 shows an arrangement of the adapter 10 according to FIG. 1 in a drive train 36 of an electrically operated machine tool 28 in a schematic, partially sectioned side view. In Fig. 3 is a schematic, lateral

Quarter-sectional view of the machine tool 28 shown in FIG. 2. In both Figures 2 and 3, the drive train 36 and the machine tool 28 are shown in a ready state.

The machine tool 28 is designed as a fine milling machine and comprises a housing 30, which includes a plurality of interconnected housing parts, including a multi-part main housing 32 and a bolted to the main housing 32 Pinolengrundkörper 34th

The machine tool 28 further includes an electric motor as the drive 38, which is designed as an electronically commutated DC motor. The electric motor is fixedly mounted in the main housing 32 and has a drive shaft 40 to which torque can be provided up to a maximum nominal torque during operation of the electric motor.

The machine tool 28 further has an output shaft 46 and a first roller bearing 56 and a second rolling bearing 62, which is arranged spaced apart in the axial direction, for supporting the output shaft 46 on the housing 30, in particular on the quill main body 34. For clarification, the arrangement of the rolling bearings 56, 62 in Fig. 4 is shown in a perspective exploded view.

The first rolling bearing 56 and the second rolling bearing 62 are each formed as a ball bearing with a fixed outer ring 58, 64 and movable inner ring 60, 66. The outer ring 58 of the first roller bearing 56 is supported by a locking ring 72 which is installed in a groove in the upper part of the sleeve main body 34. The outer ring 64 of the second rolling bearing 62 is supported on a retaining ring 74, which is in a groove in the lower part (not visible in FIG. 4) of the sleeve main body 34 is infiltrated. The outer rings 58, 64 are thus arranged in the operative state of the fine milling machine in the axial direction in a fixed position on the housing 30.

The adapter 10 is arranged in the drive train 36 between the drive shaft 40 and the output shaft 46. The drive shaft 40, the adapter 10 and the output shaft 46 are aligned in the ready state of the machine tool 28 such that their center axes are aligned.

A motor remote end of the drive shaft 40 is equipped with an adapter counterpart 42 and fixedly connected thereto (Fig. 2). As shown in Fig. 4, the adapter counterpart 42 an adapter intermediate star 44, which is provided with recesses which correspond to the two pins 20 of the adapter 10.

The two pins 20 of the adapter 10 engage for receiving the torque provided on the drive shaft 40 via the Adapterzwischenstern 44 positive and non-positive in the recesses of the adapter counterpart 42 a. The main housing 32 facing the end of the output shaft 46 is equipped with an external thread, which corresponds to the internal thread 22 of the adapter 10. At the base of the internal thread 22, a first abutment shoulder 48 is formed on the output shaft 46 (FIG. 2). In the illustrated, ready state of the machine tool 28, the external thread of the output shaft 46 is screwed to the stop 54 in the internal thread 22, so that by the stop 54 of the adapter 10 and the abutment shoulder 48 of the output shaft 46, an axial position of the output shaft 46 is fixed and the adapter 10 and the output shaft 46 via internal threads 22 and external thread form a positive and non-positive operative connection, via which a torque can be transmitted to the output shaft 46 during operation of the electric motor.

The machine tool 28 has at the end of the output shaft 46 facing away from the housing a tool holder 52 designed as a collet for receiving an insert tool, which is formed by a milling cutter (not shown) to which the torque provided by the electric motor is ultimately transmitted.

Between the contact surface 26 of the adapter 10 and the inner ring 60 of the first bearing 56, a resilient and tolerance compensating wave washer 68 and a flat disc 70 are provided.

As can be seen from FIG. 2, in the operational state of the fine milling the inner ring 60 of the first rolling bearing 56 is acted upon by the contact surface 26 of the adapter 10 via the corrugated disk 68 and the disk 70 with a defined mechanical bias.

Furthermore, the output shaft 46 has an integrally formed second contact shoulder 50 at an end remote from the main housing 32. In the ready state of the

Feinfrâse the inner ring 66 of the second rolling bearing 62 is supported by the second abutment shoulder 50. By an interaction of the adapter 10 and the output shaft 46 of the inner ring 66 of the second rolling bearing 62 is acted upon by a defined mechanical bias in the axial direction.

A determination of the defined mechanical bias on the inner ring 60 of the first bearing 56 and the defined mechanical bias on the inner ring 66 of the second bearing 62 is carried out by a vote of two dimensional chains and their tolerances.

The first of the two dimensional chains includes the axial positions of the two outer rings 58, 64 of the rolling bearings 56, 62 as well as axial positions of the retaining rings 72, 74 and corresponding grooves in the quill body 34.

The second dimensional chain includes the axial positions of the first abutment shoulder 48 and the second abutment shoulder 50 of the output shaft 46, the axial position of the stop 54 of the adapter 10, the axial position of the abutment surface 26 of the adapter 10 and the thicknesses of the corrugated washer 68 and the disc 70th

Since the torque-transmitting adapter 10 serves at the same time to the defined bias of the bearings of the output shaft 46, the tolerance chain can be reduced by a joint, which has a positive effect on the running of the system. The solution described is therefore indicated in particular for use in fine milling, but can generally also be used in other machine tools.

List of Reference Numbers 10 Adapter 60 Inner Ring 12 Base 62 Second Rolling Bearing 14 Centerline 64 Outer Ring 16 End Shaft End 66 Inner Ring 18 End Shaft Side End 68 Corrugated Washer 20 Pin 70 Washer 22 Internal Thread 72 Circlip 24 Recess 74 Circlip 26 Platen 28 Machine Tool 30 Casing 32 Main Casing 34 Pinole Base 36 Driveline 38 Drive 40 Drive shaft 42 Adapter counterpart 44 Adapter intermediate star 46 Output shaft 48 Contact shoulder 50 Contact shoulder 52 Tool holder 54 Stop 56 First rolling bearing 58 Outer ring

Claims (7)

1. Adapter (10) for torque transmission between the drive shaft (40) and output shaft (46) of a machine tool (28), in particular an electrically operated Frase, comprising: a substantially cylindrical base body (12) having a central axis (14), a drive shaft side end portion (16) and an output shaft side end portion (18), at least two on the drive shaft side end portion (16) arranged in the axial direction over the base body (12) protruding pin (20) for receiving a in an operative state of the machine tool (28) of the Drive shaft (40) output torque, and arranged along the central axis (14) internal thread (22) for mechanical connection with the output shaft (46) in the ready state of the machine tool (28) is used, and wherein the output shaft side end portion (18) at least a contact surface (26), which is provided, in the ready state on one of the rolling bearings (56) of the W Machine (28) exert a mechanical bias in the axial direction. 2. Adapter (10) according to claim 1, characterized in that the base body (12) and the pins (20) are made in one piece. 3. adapter (10) according to claim 1 or 2, characterized in that the cross-sectional areas of the pins (20) have a triangular shape, wherein one of the corners of the triangular shape to the central axis (14). 4. Adapter (10) according to claim 3, characterized in that at least one side of the triangular shape, which bears against the center axis (14) facing corner, has a concave curvature. 5. Adapter (10) according to any one of the preceding claims, characterized by an even number of pins (20) which are arranged in pairs opposite one another with respect to the central axis (14). A machine tool (28) comprising: a housing (30), a housing (30) fixed drive (38) having a drive shaft (40), an output shaft (46), one between the drive shaft (40) and the output shaft (46) arranged adapter (10) according to one of claims 1 to 5, a first roller bearing (56) and an axially spaced second rolling bearing (62) for supporting the output shaft (46), wherein the outer ring (58) of the first Rolling bearing (56) and the outer ring (64) of the second roller bearing (62) in the axial direction fixed to the housing (30) are arranged, characterized in that in the ready state of the machine tool (28), the first roller bearing (56) at least by the contact surface (26) of the adapter (10) and the second roller bearing (62) are acted upon at least by a cooperation of the adapter (10) and the output shaft (46) with a defined mechanical bias in the axial direction. 7. Machine tool (28) according to claim 6, characterized in that the drive (38) is designed as an electronically commutated DC motor.