Multi-functional spindle for machine tools

Abstract

This invention relates to a multifunctional mandrel for a workpiece machining machine. The multifunctional mandrel includes a mandrel housing, a rotary drive, and a tool receiving unit, wherein the tool receiving unit is disposed within the mandrel housing and pivots relative to the mandrel housing about an axis perpendicular to the rotation axis. The problem solved by this invention is to provide a corresponding multifunctional mandrel, particularly effective in turning polygonal profiles, capable of quickly and substantially completely compensating for imbalances and improving the positioning accuracy of the axis perpendicular to the drive shaft, while ensuring functional safety. The solution to this problem is as follows: At least two independent and adjacent measuring systems for sensing the same position angle are connected to the tool receiving unit so that the position angle signal measured by the measuring systems is transmitted to the controller of the machine tool equipped with the multi-functional spindle via at least two independent transmission paths through a transmission unit. At least one transmission path is used for position control, and at least one transmission path is used to ensure the functional safety of the pivot axis perpendicular to the drive axis. The transmission unit supplies power to the at least two connected measuring systems without contact. The transmission unit consists of at least two parts that rotate relative to each other at the rotational speed of the spindle, and the transmission unit has a central hole through which a media conduit passes from the center.

Description

Technical Field

[0001] This invention relates to a multifunctional mandrel for a workpiece machining machine tool. The multifunctional mandrel includes a mandrel housing, a rotary drive, and a tool receiving unit, wherein the tool receiving unit is disposed within the mandrel housing and pivots relative to the mandrel housing about an axis perpendicular to the rotation axis. Background Technology

[0002] Machine tools used for machining workpieces in many designs are known. In a lathe, the workpiece rotates while a stationary tool moves axially and radially relative to the workpiece to form a rotationally symmetrical circular profile. In a drilling machine, the tool rotates and is driven against a stationary workpiece to form a hole. In a milling machine, a rotating tool moves radially and axially relative to a stationary workpiece to form grooves, milled surfaces, or freeform surfaces. In these machine tool types, the tool is typically housed and firmly clamped in a tool mandrel via a tool interface. In principle, a tool mandrel includes a rotary driver, a rotary drive shaft, and an output shaft, with the tool housing integrated into the output shaft. Such tool mandrels are also used in machining centers, where appropriate tools are automatically loaded. Furthermore, such tool mandrels are suitable for machine tools that manufacture non-circular profiles; these machining operations are typically cam turning or polygon turning. In this process, it is necessary to control the rotating tool with a cutting head and the similarly rotating workpiece to control the number of revolutions they make relative to each other.

[0003] To adapt to different machining processes, the original tool spindle needs to be specially modified. However, EP3216557 discloses a multi-functional tool spindle suitable for both traditional machining operations such as turning, boring, and milling, and emerging machining operations such as polygon turning. This tool spindle includes a housing, a rotary drive, and a tool receiving unit in a manner known per se. However, in this case, the tool receiving unit is arranged within the spindle housing and can move relative to the spindle housing about an axis perpendicular to the drive shaft.

[0004] Within the scope of this specification, the basic principle of such a tool spindle suitable for performing different machining processes on a machine tool is referred to hereinafter as a "multi-functional spindle".

[0005] Despite the attractive opportunities this versatile mandrel offers for many applications, market acceptance has remained low to date. This is likely due to functional defects that occur during polygonal turning at higher speeds. In the aforementioned operational considerations, the significant effects of imbalance, as disclosed in EP3216557 regarding metering equipment, coolant supply, and imbalance compensation design, cannot be fully compensated for.

[0006] EP0922528B1 discloses a principle similar to the aforementioned multifunctional mandrel, in which the required positioning accuracy or functional safety of the axis perpendicular to the drive shaft can be achieved, possibly by using only a single measuring system. However, this mandrel cannot be used commercially due to insufficient positioning accuracy or unreliable design. Summary of the Invention

[0007] The problem solved by this invention is to provide a multifunctional mandrel, which, especially when turning polygonal profiles, can quickly and substantially completely compensate for imbalances and improve the positioning accuracy of the axis perpendicular to the drive shaft, while ensuring functional safety.

[0008] This problem is solved as follows: To improve positioning accuracy, at least two independent and adjacent measuring systems for sensing the same position angle are connected to the tool receiving unit. The position angle signals measured by these measuring systems are then transmitted via a transmission unit to the controller of the machine tool equipped with the multi-functional spindle through at least two independent transmission paths. During this process, at least one transmission path is used for position control, and at least one transmission path ensures the functional safety of the pivot axis perpendicular to the drive axis. The transmission unit supplies power to the at least two connected measuring systems without contact. The transmission unit consists of at least two parts that rotate relative to each other at the rotational speed of the spindle. Furthermore, the transmission unit has a central bore through which a media conduit passes from the center.

[0009] According to one embodiment, the spindle has at least two axially adjacent annular grooves, each annular groove having an annular section supplied with hydraulic fluid via a conduit, thereby enabling adjustment of the relative position of the annular section within the annular groove to compensate for imbalance.

[0010] According to another advantageous embodiment, the spindle housing is equipped with at least two independent rotary joints. At least one of these rotary joints is designed as a hydraulic supply conduit for housing a hydrodynamic bearing of the spindle assembly. The bearing can be established by defining a suitable drain fluid from the control conduit of the rotary joint by superimposing it with the rotational speed of the machine tool spindle. The other rotary joint is centrally located and leak-free, and preferably supplies cooling lubricant and pneumatic fluid. Because the hydraulic rotary joint and the rotary joint for cooling lubricant are separate from each other, the hydrodynamic bearing can be formed without contamination. Attached Figure Description

[0011] Other advantageous designs will now be described as exemplary embodiments based on the accompanying drawings. In the drawings:

[0012] Figure 1 A cross-sectional view of the multifunctional mandrel structure according to the present invention is shown;

[0013] Figure 2 The setup of the first annular section for compensating for imbalance is shown; and

[0014] Figure 3 The setup for the second annular section used to compensate for imbalance is shown. Detailed Implementation

[0015] Figure 1 The multi-functional mandrel shown is designed for machine tools used for machining workpieces. The mandrel assembly 1 is housed within the mandrel housing 2 and supported within the housing 2 by a front bearing 3 and a rear bearing 4. The front bearing 3 is formed by two separately arranged bearing sections 3' and 3"". The mandrel assembly 1 rotates about a shaft 24, and the rotary actuator causing this rotation includes a stator unit 5 and a rotor unit 6.

[0016] The multi-functional spindle includes at least two rotary joints or conduits 11 for hydraulic and pneumatic operation, and rotary joints or conduits 12 and 23 for cooling lubricant and pneumatic operation.

[0017] At the end (not shown) facing the workpiece, the spindle member 1 has a groove in which a tool receiving unit 9 is disposed. The tool receiving unit 9 is arranged such that it can rotate relative to the spindle housing 2 about an axis 10 perpendicular to the rotation axis 24. The aforementioned pivot rotation is indicated by an arched arrow.

[0018] The cutting tool 8 is clamped on the end face of the cutting tool receiving unit 9, facing the workpiece. A workpiece gauge 13 is positioned on the opposite end face, and two measuring heads 14 are positioned adjacent to the workpiece gauge 13. In a further configuration, a telemetry transmitter 15 and a telemetry receiver 16 are positioned behind the measuring heads 14.

[0019] The first annular segment 22 and the second annular segment 7 are disposed between bearing segments 3' and 3" and are not far apart from each other. The two annular segments 22 and 7 have annular profiles and are respectively guided into continuous annular grooves extending circumferentially on the spindle member 1. During operation of the multi-functional spindle, imbalances can be compensated for by the annular segments 7 and 22, which will be explained in more detail below. For this purpose, at least two such annular segments 22 and 7 are required; however, more annular segments can also be provided.

[0020] Data collected during the operation of the multi-functional mandrel and any parameter adjustments that may be made can be generated wirelessly or via measurement lines. In the accompanying drawings, these measurement lines are shown exemplarily as line 25 leading to the measuring head 14, line 26 leading to the telemetry receiver 16, and line 27 leading to the hydraulic and pneumatic components.

[0021] During workpiece machining or operation of the multi-functional spindle, if the position of the tool receiving unit 9 deviates from its optimal position, thus posing a risk of imbalance, the physical gauge 13, which is operatively connected to the measuring head 14, will detect this anomaly. Subsequently, a corresponding signal will be transmitted to the lathe controller, which will trigger a change in the hydraulic pressure supplied to the annular grooves of the annular sections 7 and 22.

[0022] according to Figure 2 Hydraulic pressure can be supplied through holes 17 and 18 to an annular groove containing an annular section 7. Holes 17 and 18 are located at the ends of the annular groove, which is separated by a pressure chamber partition 19. In this manner, the relative position of the annular section 7 within the annular groove can be changed.

[0023] At the same time, according to Figure 3 Hydraulic pressure can be supplied through holes 20 and 21 to an annular groove containing an annular section 22. Holes 20 and 21 are located at the ends of the annular groove, which is separated by a pressure chamber partition 19. In this manner, the relative position of the annular section 22 within the annular groove can be changed.

[0024] Therefore, the annular segments 7 and 22 may become misaligned, moving to a position offset from each other by 180°, thereby better compensating for any imbalance. Since imbalances are particularly prone to occur when machining polygonal profiles, the multifunctional mandrel according to the invention is especially advantageous for polygonal turning.

[0025] Figure Labels

[0026] 1. Mandrel Shaft

[0027] 2. Mandrel housing

[0028] 3. Front bearing of the spindle assembly

[0029] 3' Independent bearing section

[0030] 3” independent bearing section

[0031] 4. Rear bearing of the spindle assembly

[0032] 5 stator units

[0033] 6 Rotor Units

[0034] 7. Circular Section

[0035] 8 knives

[0036] 9. Tool receiving unit

[0037] 10. Pivot axis perpendicular to the main shaft rotation axis

[0038] 11 Rotary joints for hydraulic and pneumatic applications

[0039] 12 Rotary joints for cooling lubricants and pneumatic applications

[0040] 13 Physical measuring tools

[0041] 14 Measuring head

[0042] 15 Telemetry Transmitters

[0043] 16 Telemetry Receiver

[0044] 17. Holes leading to the annular groove of annular section 7

[0045] 18. Holes leading to the annular groove of annular section 7

[0046] 19 Pressure chamber partition

[0047] 20. Hole leading to the annular groove of the annular section 22

[0048] 21. Hole leading to the annular groove of the annular section 22

[0049] 22. Circular section

[0050] 23 Rotary joints for cooling lubricants and pneumatic applications

[0051] 24. Rotating shaft of mandrel component

[0052] 25. Connection lines for the measuring head

[0053] 26. Connection line to the telemetry receiver

[0054] 27. Wiring for hydraulic / pneumatic components

Claims

1. A multifunctional mandrel for a workpiece machining machine tool, comprising: A spindle housing, a rotary actuator, and a tool receiving unit, wherein the tool receiving unit is disposed within the spindle housing and pivots relative to the spindle housing about an axis perpendicular to the axis of rotation; The invention is characterized by: at least two independent and adjacent measuring systems for sensing the same position angle being connected to the tool receiving unit, so that the position angle signal measured by the measuring systems is transmitted via at least two independent transmission paths to the controller of the machine tool equipped with the multifunctional spindle through a transmission unit, wherein at least one transmission path is used for position control, and at least one transmission path is used to ensure the functional safety of the pivot axis perpendicular to the drive axis; wherein the transmission unit supplies power to the at least two connected measuring systems without contact; wherein the transmission unit consists of at least two parts that rotate relative to each other at the rotational speed of the spindle; and wherein the transmission unit has a central hole through which a media conduit passes from the center.

2. The multifunctional mandrel according to claim 1, characterized in that, The spindle has at least two axially adjacent annular grooves, each annular groove having an annular section supplied with hydraulic pressure via a pipe, thereby enabling adjustment of the relative position of the annular section within the annular groove.

3. The multifunctional mandrel according to claim 2, characterized in that, The front bearing of the mandrel assembly is designed with two independent bearing sections. Between the bearing sections are a first annular section and a second annular section that are not far apart. Each annular section has an annular profile and is guided into a continuous annular groove extending in the circumferential direction of the mandrel assembly.

4. The multifunctional mandrel according to claim 2, characterized in that, Each of the annular grooves has a hole for supplying hydraulic pressure, wherein the holes are spaced apart from each other at the two ends of the annular groove, which is separated by a pressure chamber partition.

5. The multifunctional mandrel according to claim 2, characterized in that, The spindle housing is equipped with at least two independent rotary joints, wherein at least one of the rotary joints is designed as a hydraulic supply conduit for accommodating a hydrodynamic bearing of the spindle shaft, wherein the bearing is established by defining a suitable drain fluid from the control conduit of the rotary joint by superimposing it with the rotational speed of the machine tool spindle, and wherein at least one other rotary joint is designed as a central channel for cooling lubricant and pneumatics.

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