Machine tool having a workpiece changing device

Abstract

A machine tool for machining workpieces, wherein the machine tool has at least one first spindle assembly with at least one working spindle on which a machining tool for workpiece machining is arrangeable, wherein the machine tool has a workpiece holding device for holding workpieces for the purpose of workpiece machining by way of the machining tool, wherein the machine tool has a guide arrangement for the relative positioning of the workpiece holding device holding the workpieces and the first spindle assembly for workpiece machining, wherein the guide arrangement comprises a workpiece-holder guide for guiding the workpiece holding device so as to position a workpiece holder holding the workpieces relative to the first spindle assembly.

Claims

1. A machine tool for machining workpieces, wherein the machine tool comprises at least one first spindle assembly having at least one working spindle on which at least one working spindle a machining tool for machining workpieces can be mounted, wherein the machine tool comprises a work holding device including a work holder for holding workpieces for workpiece machining by means of the machining tool, wherein the machine tool comprises a guide arrangement for the relative positioning of the work holding device holding the workpieces and of the at least one first spindle assembly for workpiece machining, wherein the guide arrangement comprises a work holder guide for linearly guiding the work holding device for a positioning of the work holder holding the workpieces relative to the at least one first spindle assembly, and wherein the machine tool further comprises a loading and unloading device for exchanging workpieces at the work holding device, wherein a control unit is configured to cause the loading and unloading device to follow a positioning movement of the work holder as the work holder is linearly guided by the guide arrangement while workpieces are being machined by the respective machining tool, and to cause the loading and unloading device to exchange, at the work holder, at least one workpiece not being machined while another workpiece held by the work holder is being machine by the at least one first spindle assembly.

2. A machine tool according to claim 1, wherein in order to synchronise the movements of the work holding device and the loading and unloading device, the machine tool comprises: (i) the control unit being a common control unit for controlling the work holding device and the loading and unloading device, or (ii) the control unit includes a holder control unit provided for controlling the work holding device and a loading and unloading control unit synchronised with the holder control unit and provided for controlling the loading and unloading device.

3. A machine tool according to claim 1, wherein the control unit is configured for: (i) the execution of a first control module and a second control module, which can be executed jointly on a processor of the control unit and directly communicate with one another, via a common storage area, or (ii) wherein the control unit is configured for the execution of a single control module, which is configured for the control of the work holding device and the loading and unloading device.

4. A machine tool according to claim 1, wherein the loading and unloading device or its control unit comprises an input interface, via which a position signal indicating the position of the work holding device can be received by the control unit, and wherein the loading and unloading device is further configured to perform additional positioning movements, including a positioning movement provided for exchanging workpieces at the work holding device while the work holding device is stationary.

5. A machine tool according to claim 1, wherein a position marking is provided on the work holding device, and wherein the loading and unloading device comprises a locating device for locating and tracing the position marking, so that the loading and unloading device can follow a movement of the work holding device.

6. A machine tool according to claim 1, wherein a workpiece magazine for holding at least two workpieces is provided on the loading and unloading device, so that the loading and unloading device can simultaneously exchange at least two workpieces at the work holding device.

7. A machine tool according to claim 1, wherein at least one feed device for feeding the respective workpiece and/or a latching device for latching the respective workpiece is/are provided on the work holding device.

8. A machine tool according to claim 1, wherein the work holding device is configured to be moved into a holding position provided for holding a workpiece and/or into a release position provided for releasing and removing a workpiece.

9. A machine tool according to claim 1, wherein the loading and unloading device is configured for positioning the workpieces in at least one further working station, away from the work holding device, for deburring and/or measuring of the workpieces.

10. A machine tool according to claim 1, wherein the loading and unloading device is, in addition to exchanging workpieces, configured for passing through a frame of the work holding device, and is configured for exchanging machining tools at a tool magazine and/or at at least one stationary working spindle in a working region.

11. A machine tool according to claim 1, further comprising at least one second spindle assembly having at least one working spindle.

12. A machine tool according to claim 11, wherein the at least one working spindle of the at least one first spindle assembly comprises at least two working spindles, and/or the at least one working spindle of the at least one second spindle assembly comprises at least two working spindles.

13. A machine tool according to claim 12, wherein the at least one first spindle assembly is guided on a first spindle assembly guide of the guide arrangement, and wherein the at least one second spindle assembly is guided on a second spindle assembly guide that is separate from the first spindle assembly guide of the guide arrangement, so that the at least one first spindle assembly and the at least one second spindle assembly are movable independently of one another into: (i) a working region, in which the workpieces are machined on the work holding device, and (ii) a tool changing region in which machining tools of the working spindles are exchanged.

14. A machine tool according to claim 13, wherein the tool changing region is provided for at least two of the spindle assemblies, is provided on a single tool changing side of the machine tool, and is adjacent to the working region, so that the at least two spindle assemblies are moved to the same tool changing side of the machine tool for tool change.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are explained below with reference to the drawing, of which:

(2) FIG. 1 is a perspective oblique view of a first machine tool according to the invention with a shelf magazine and a control unit,

(3) FIG. 2 shows the machine tool from FIG. 1, but with two further work stations served by a loading an unloading device in the form of a working robot,

(4) FIG. 3 shows the machine tool from FIG. 1, but illustrating details by partially removing components,

(5) FIG. 4 shows a variant of the embodiment from FIG. 1, but with a drum magazine,

(6) FIG. 5 shows a further variant of the embodiment from FIG. 1, but with a chain magazine, and

(7) FIG. 6 shows a second embodiment of a machine tool according to the invention with an alternative spindle assembly guide arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) In the following description, identical or similar components are partly identified by the same reference numbers. In the case of those variants of the machine tool from FIG. 1 which are shown in FIGS. 4 and 5, reference numbers with an added letter a or b are used on occasion, while the reference numbers for the embodiment according to FIG. 6 are increased by 100 compared to FIGS. 1 to 5. The variants mentioned in the context of the different embodiments can obviously be combined readily.

(9) On a machine bed 11 of a machine tool 10, a frame 20 with a first spindle assembly 21, a second spindle assembly 22 and a third spindle assembly 23, each having a total of four working spindles 24, is mounted.

(10) On the diagrammatically illustrated working spindles 24, machining tools 25, in particular drill heads, milling tools or the like, which are in particular provided for chip removal or a grinding operation, are releasably mounted. With these machining tools, workpieces P illustrated diagrammatically in FIG. 3 can be machined. The workpieces P may, for example, be connecting rods or other metal components. The machine tool 10 is obviously suitable for other workpieces as well, for example for engine blocks or the like. In this context, it should be stated that a machining of engine components is a preferred application of the invention.

(11) The frame 20 is constructed in the manner of a tower.

(12) The spindle assemblies 21 to 23 are arranged vertically on top of one another, i.e. in the direction of a Y-axis. The spindle assembly 21 is the bottom unit, the spindle assembly 22 the middle unit and the spindle assembly 23 is the top unit of the arrangement.

(13) The working spindles 24 of the spindle assemblies 21 to 23 are in each case accommodated in a spindle housing 26.

(14) The spindle assembly 23 is stationary in the working region A of the machine tool 10, which is provided for machining workpieces, while the two other spindle assemblies 21, 22 are mobile spindle assemblies in a manner of speaking, being movable between the working region A and a tool changing region W. In the tool changing region W, machining tools are exchanged, while the workpieces P are machined in the working region A. The tool changing region W is provided on a tool changing side 42 adjacent to the frame 20.

(15) A guide arrangement 30 with a first spindle assembly guide 31 for the spindle assembly 21 and a second spindle assembly guide 32 for the spindle assembly 22 facilitate the movement of the spindle assemblies 21, 22 between the working region A and the tool changing region W.

(16) The spindle assembly guides 31, 32 comprise guide rails 35, which extend in the direction of guide axes 33, 34 and on which the spindle housings 26 of the spindle assemblies 21, 22 are mounted for linear movement in the manner of slides. Linear guides 36 are thus implemented. The spindle housings 26 can obviously form slides themselves, but they can also be mounted on a slide.

(17) The slides or spindle housings 26 of the spindle assemblies 21, 22 can be driven independently by drives 37, 38 and can therefore be moved independently along the guide axes 33, 34. The drives 37, 38 are electric motors and/or fluidic, e.g. pneumatic or hydraulic, drives, for example.

(18) The guide axes 33, 34, which can also be described as movement axes, extend parallel to an X-direction, i.e. in the X-direction in a manner of speaking.

(19) The working spindles 24 of each spindle assembly 21, 22, 23 are arranged in a row direction 27 adjacent to one another in the same way as the guide rails 33, 34, i.e. in the direction of the X-axis.

(20) The spindle assemblies 21, 22, 23 have a quasi-flat configuration and can therefore be arranged indirectly on top of one another at a small distance in the direction of the Y-axis.

(21) The working region A and the tool changing region W are, for example, separated from one another by a bulkhead 40, so that any chips, coolant or the like found in the working region A cannot enter the tool changing region W.

(22) A further bulkhead 41, which is also indicated diagrammatically, is provided between the working region A and a loading and unloading region S provided for exchanging workpieces P.

(23) The bulkheads 40, 41 can obviously be multi-part units and comprise one or more movable components. The bulkhead 40 can have one or more openings, enabling the spindle assemblies 21, 22 to be moved from the working region A to the tool changing region W and vice versa.

(24) The bulkhead 41 can likewise have one or more openings. In any case, the bulkhead 41 allows a work holding device 50 to be movable.

(25) The work holding device 50 comprises a work holder 51, for example. The work holder 51 comprises a beam-type holding body 52 with a plurality of work holding regions 53, 54 (or further work holding regions), which are arranged at an angle to one another. The holding body 52 is mounted on bearing blocks 56 for pivoting about a pivot axis 55. The bearing blocks 56, together with the holding body 52, in their turn form a slide 57, which is movably mounted on a frame-like base 58 of the work holding device 50, being movable in a Y-direction.

(26) At a front side of the frame 58, which faces the frame 20, there may, for example, be guide rails of a work holder guide 59, which facilitate a movement of the work holder 51 in the Y-direction. A diagrammatically indicated drive 60 drives the slide 57. The work holder guide 59 is a linear guide.

(27) The frame 58 is likewise mounted for linear movement on guide rails 61 of a work holder guide 62, moving not in the Y-direction, however, but in the direction of a Z-axis. The frame 58 can therefore move the work holder 51 in the manner of a slide towards the working spindles 24 and away therefrom along the Z-axis, for example in order to produce bores.

(28) The work holder guides 59, 62 guide the work holder 51 in the direction of a first workpiece guide axis 63 and a second workpiece guide axis 64.

(29) The other slide 57 facilitates the movement of the work holder 51 in the direction of the Y-axis, so that the work holder 51 can be positioned relative to the spindle assembly 21, 22, 23 involved in the machining process. The spacing of these spindle assemblies 21, 22, 23 in the Y-direction is preferably dimensioned such that the spindle assembly 21, for example, can be moved from the working region A into the tool changing region W without impediment, while the work holder 51 stands in front of the spindle assembly 22 or 23. It is, however, also possible to choose a smaller spacing in the Y-direction, for example between the spindle assemblies 22 and 23, so that the working spindles 24 of two spindle assemblies 21 and 22 or 22 and 23 can machine workpieces P simultaneously if they are made available frontally by the work holder 51.

(30) For positioning workpieces P relative to the machining working spindles 24, the guide arrangement 30 comprises both the spindle assembly guides 31, 32 and the work holder guides 59, 62. All guides are linear guides, but it is possible for one or more guides to be designed as rotary guides, so that workpieces P and/or working spindles 24 are pivoted for machining, for example. It is, for example, possible for the work holder 51 to be pivoted about the pivot axis 55 in the machining process.

(31) In the tool changing region, a tool magazine 70, 170, for example a shelf magazine 71 (FIGS. 1 and 2) or a shelf magazine 171 as in the machine tool 110 shown in FIG. 6, is expediently provided.

(32) The machine tool 10a, on the other hand, is provided with a drum magazine 72, while the machine tool 10b has a chain magazine 73.

(33) All tool magazines 70, 170 allow the simultaneous exchange of several machining tools 25 at the spindle assembly 21, 22 presently located in the tool changing region W. The machining tools 25 made available at any one time are arranged side by side in the row direction 27.

(34) A holder 74a of the shelf magazine 71, 171 may, for example, have several tiers, in each of which are located four machining tools 25 arranged side by side in the row direction 27. The holder 74a of the shelf magazine is, for example, guided on a stand 74 for linear movement in the Y-direction and can be positioned by a drive not shown in the drawing for bringing the currently required row of machining tools 25 into position in front of the respective spindle assembly 21, 22.

(35) In the drum magazine 72, a drum 75 is movable in the Y-direction by means of a slide 76 on a stand 77. On its outer circumference, parallel to its axis of rotation 78, about which it is mounted to rotate on the stand 77, the drum 75 is provided with several rows of tool holders 80 for machining tools 25. By rotating about the axis of rotation 78, a suitable row of tool holders 80 or machining tools 25 respectively can be brought into position in front of the spindle assembly 21 or 22, while the slide 76 adopts the suitable Y-position. For simplicity, the drives for the drum 75 and the slide 76 are not shown.

(36) The chain magazine 73 comprises several chain runs 79, for example 3 or 4 (corresponding to the number of working spindles 24 of the respective spindle assembly 21). The chain runs 79 support tool holders 80 for holding machining tools 25.

(37) The chain runs 79 or the tool holders 80 mounted thereon are arranged side by side in the row direction 27, so that 4 tool holders 80 can be in position in front of the spindle assembly 21 and the spindle assembly 22 whenever these spindle assemblies 21, 22 are in the tool changing region W. On any one chain run 79, 2 tool holders 80 can, for example, be arranged in the row direction 27.

(38) The chain runs 79 are advantageously arranged in such a way that a front section 81 of the run extends in the tool changing region W in front of the respective spindle assemblies 21, 22 or in front of the section of the spindle assembly guides 31, 32 which extends into the tool changing region W, while a rear section 82 of the run is easily accessible, for example for an operator B or a loading and unloading device 90. Between the sections 81, 82, there are sections 83, 84, which extend along or parallel to the Z-axis, for example.

(39) With the various tool magazines 70, 170, it is therefore possible for the spindle assembly 21, 22 which is currently in the tool changing region W to deposit all machining tools 25 simultaneously in free tool holders 80 and to pick up another group of machining tools 25. This process is very fast and effective. In this context, it has to be noted that, during the tool change, the respective other spindle assembly 21, 22 continues the machining process in the working region A, allowing for uninterrupted operation.

(40) The handling and the optimised fast machining process are improved further by the efficiently operating loading and unloading device 90 described below.

(41) The machine tool 10, 110 is equipped with a working robot 91, which is provided for exchanging the workpieces P at the work holding device 50 and forms the loading and unloading device 90. The loading and unloading device 90, however, exchanges workpieces P not only while the machine tool 10, 110 is stopped, i.e. while the work holder 51 is stationary, but also while the latter moves relative to the frame 20, for example along the tool holder guide 59 and/or 62 during the machining process. The working robot 91 follows this movement.

(42) The working robot 91 comprises a pedestal 92, for example, on which a base 93 is mounted for rotation about an axis 94. From the base 93, an arm 95 extends, which is in turn mounted on the base 93 for pivoting about a further axis 96. The arm 95 in turn supports a further arm 97 for pivoting about an axis 97a. This being so, a gripping element 98 mounted at the front of the arm 97 is largely capable of free movement in three dimensions. The working robot 91 may, for example, be a so-called articulated arm robot.

(43) The gripping element 98 supports a magazine holder 99, for example, by means of which the working robot 91 or the loading and unloading device 90 can simultaneously pick up and/or deposit several workpieces P, for example 4.

(44) A control unit 100, for example with a processor 101, is configured for the control of the loading and unloading device 90 and the work holding device 50. Suitable control lines (not shown) are, for example, provided between the control unit 100 and the loading and unloading device 90 as well as the work holding device 50. The control unit 100 further comprises a memory 102, in which a control module 103 is stored. The control module 103 is a programme module with a programme code executable by the processor 101. By executing the control module 103, the control unit 100 controls the loading and unloading device 90 and the work holding device 50 simultaneously in such a way that the work holding device 50 positions the workpieces P relative to the working spindles 24 for machining while the working robot 91 simultaneously follows this movement and exchanges workpieces P which are, for example, in the work holding region 53 or 54 and not pivoted into the working region A.

(45) In addition, the loading and unloading device 90 is multi-functional insofar as it can, for example, place machining tools 25 in the tool magazine 70 or remove them when no workpiece exchange is imminent and/or the machine tool 10 has a break.

(46) By way of example, FIG. 2 shows 2 further work stations Q and R, where the workpieces P can be deburred and measured, for example. The working robot 91 can, for example, initially remove the workpieces P from the work holder 51 and then successively deposit them at the work stations Q and R for further processing.

(47) In the concept of the machine tool 110 according to FIG. 6, components matching the above description are drawn and indicated using the same reference numbers.

(48) On the top of a frame 120 of the machine tool 110, a stationary spindle assembly 123 is provided, below which is located a spindle assembly 122, which can be moved along a spindle assembly guide 132 between the working region A and the workpiece changing region W in the direction of the X-axis. Below the spindle assembly 122, there is a further mobile spindle assembly 121, which is likewise movable in the direction of the X-axis between the working region A and the workpiece changing region W. Like the spindle assemblies 21 and 22, the spindle assemblies 121 and 122 can therefore be moved between the working region A and the workpiece changing region W for machining or for the exchange of workpieces.

(49) There is, however, a difference in that the guide rails 135 of the spindle assembly guide 132 are directly mounted on the frame 120, for example at the front facing the work holding device 50, while the guide rails 139 of the spindle assembly guide 131 are mounted below on the machine bed 11. The guide elements of the spindle assembly guides 131, 132 are therefore not placed on one and the same base.

(50) FIG. 6 further shows that the mobility of the working robot 91 is designed such that it can project or grip as far as the working spindles 24 of the stationary spindle assembly 23, 123. Its gripping element 98 can, for example, remove machining tools 25 from these stationary working spindles 24 and exchange them against other machining tools 25. The gripping element 98 can, for example, deposit the machining tools 25 in one of the tool magazines 70, 170 or pick them up from there. This provides a further function for the loading and unloading device 90.

(51) A further control concept for the loading and unloading device 90, which makes it follow the positioning movements of the work holding device 50, is indicated in the context of FIG. 6.

(52) In this embodiment, the control unit 100 comprises a first control module 104 for the control of the work holding device 50 and a second control module 105 for the control of the loading and unloading device 90, both of which are directly executed by the processor 101. A particularly simple aspect of this concept is that the control modules 104, 105 directly communicate with one another, for example for matching the movement of the loading and unloading device 90 to that of the work holding device 50. The control module 105, for example, is provided with an input interface 106, via which the control module 105 receives from the control module 104 position messages relating to imminent or current positioning movements of the work holding device 50.

(53) A further variant can provide that, for example on the work holder 51, a position marking 107 is provided, which is detected by a locating device 108 on the loading and unloading device 90. The locating device 108 comprises, for example, at least one radio receiver, a camera or other receiving elements designed for radio-based or optical location. Using the position marking 107, the loading and unloading device 90, for example the control module 105, can detect the current position of the work holder 51 and therefore simultaneously track the position of the gripping element 98 or the magazine holder 99 respectively.

(54) The locating device 108 and the position marking 107 are also advantageous for the implementation of a safety concept, i.e. using these components, the control module 103 or 104 checks whether the loading and unloading device 90 is optimally positioned relative to the work holding device 50.

(55) This positioning can obviously be subject to certain tolerances. In this case, it is advantageous if a latching device 15 and/or a feed slant or device 16 is/are provided in the tool holding regions 53, 54 on the diagrammatically illustrated work holders, which may, for example, include clamping jaws, a clamping face or the like.