EP3535092B1 - Honing machine having multiple workstations - Google Patents

Description

FIELD OF APPLICATION AND STATE OF THE ART

The invention relates to a honing machine for carrying out honing operations on at least one bore in a workpiece, in particular for honing cylinder bores in a cylinder crankcase.

Honing is a machining process with geometrically indeterminate cutting edges in which a multi-edged honing tool with bonded cutting material executes a two-component working movement in the bore during a honing operation, which leads to a characteristic surface structure of the machined inner surface, usually with crossed machining tracks. The working movement transmitted from a honing spindle of a honing machine to the honing tool therefore generally consists of an axially reciprocating stroke movement and a rotary movement superimposed on this. Finished surfaces can be produced by honing, which meet extremely high requirements in terms of dimensional and shape tolerances as well as in terms of surface structure. Correspondingly, in engine construction, for example, cylinder sliding surfaces, i.e. inner surfaces of cylinder bores in a cylinder crankcase or in a cylinder sleeve to be installed in a cylinder crankcase, bearing surfaces for shafts, e.g. in a crankshaft bearing bore, or the cylindrical inner surfaces in connecting rod eyes are subjected to honing. Bearing surfaces on connecting rods, gears or components for other engines and machines, such as compressors, are often machined by means of honing.

When machining cylinder sliding surfaces, several different, successive honing operations are typically carried out, e.g. pre-honing to create the required basic shape and finish honing, with which the ultimately required surface structure is created. The success of the processing can be checked by measuring steps.

In the mass production of cylinder crankcases and other workpieces to be machined by honing, honing machines with several honing units are often used, which include, for example, a pre-honing unit and a finished honing unit, a pre-honed workpiece being able to be transferred directly to the finished honing unit within the honing machine. Equipment for further processes, such as measuring and deburring, can be integrated into such a honing machine.

The WO 2013/117482 A1 describes a honing machine for performing honing operations on cylinder bores in a cylinder crankcase. The honing machine has a machine base, several vertical columns arranged in the edge area of the machine base, and a machine upper part carried by the columns, which is arranged at a distance above the machine base. A rotary table is arranged on the machine base in order to transport workpieces one after the other to different work stations of the honing machine. Two of the work stations are honing stations, each of which has at least one honing unit carried by the machine head, which has a honing spindle that is rotatable about a vertical spindle axis and can be moved back and forth parallel to the spindle axis. The honing unit is attached to a horizontally movable slide that is carried by the machine head. In some embodiments, the honing unit can be moved to a tool changer with the aid of the slide.

The utility model DE 20 2016 002 857 U1 describes honing machines with several honing stations, in which a machine head is carried by a column and a rotary transport system equipped with a rotary table, for example, is provided for transporting workpieces, which transports the workpieces on a transport path running around the column between work stations. Two of the work stations are each honing stations which have at least one honing unit carried by the machine head, which has a honing spindle that is rotatable about a vertical spindle axis and can be moved back and forth parallel to the spindle axis. The honing unit is attached to a horizontally movable slide that is carried by the machine head. In some embodiments, the honing unit can be moved to a tool changer with the aid of the slide.

With honing machines of the types described, with suitable dimensioning and design of workpiece-dependent components, complete machining of cylinder bores on cylinder crankcases is possible with short non-productive times that are not available for machining. The honing machines are also characterized by a relatively compact design and therefore only require little space. In addition, they can be linked relatively easily with other processing machines to form processing lines.

TASK AND SOLUTION

The invention is based on the object of providing a generic honing machine which is characterized by high achievable productivity and flexibility while at the same time having a very compact design. In particular, a compact honing machine should be provided with which enables complete machining of cylinder bores on cylinder crankcases with short idle times.

To solve this problem, the invention provides a honing machine with the features of claim 1. Advantageous further developments are given in the dependent claims. The wording of all claims is incorporated into the content of the description by reference.

The term “honing machine” denotes a numerically controlled processing machine with which at least one honing operation can be carried out on a workpiece, so that the processing machine is suitable for honing. The honing operation is carried out at a honing station. The honing machine can be designed as a pure honing machine, in which all work stations (processing stations) set up for machining the workpiece are designed as honing stations. If necessary, the honing machine can also be used to carry out other, typically material-removing, machining operations on a workpiece, e.g. one or more drilling operations, a deburring operation or a fluid jet operation. Appropriate workstations can be provided for this. A measuring station can also be integrated if necessary.

In the honing machines considered here, a honing station has at least one horizontal slide which is carried by the machine head and which can be moved in a horizontal direction in a numerically controlled manner by means of a horizontal slide drive. The horizontal slide carries at least one honing unit which has a honing spindle which is rotatable about a vertical spindle axis and can be moved back and forth parallel to the spindle axis. The honing unit or the honing spindle can be positioned in different positions in the horizontal direction due to the arrangement on the horizontal slide.

It is possible to arrange a horizontal slide on an upper side of the machine head. However, the horizontal slide is preferably attached to a side surface of the machine head. As a result, mutual interference between horizontal slides can be better avoided even with a compact design.

A support structure is assigned to the machine base or the machine base of the honing machine, so that there is a fixed spatial relationship between the machine base and the support structure. The support structure can for example be arranged or mounted on the machine base so that the machine base carries the support structure. The support structure can also stand directly on the floor and only with the machine base be screwed so that it acts mainly as a lateral support for the support structure.

The support structure is a load-bearing assembly for the mechanical-functional components of the honing machine. These can be mostly or exclusively attached to the machine head supported by the support structure. This applies in any case to the horizontal slides (one or more) and all components carried by a horizontal slide, e.g. the honing units. Supply lines for electrical, pneumatic and / or hydraulic components, for example, can run on and / or in the support structure or one of its components.

The honing machine has a transport system for transporting workpieces on a transport path. The transport system forms a machine-internal transfer system with which the workpieces can be transferred quickly between the individual workstations. The transport system can e.g. be mounted on the machine base. The term "transport path" here describes the path that a transported workpiece can take during transport.

Several work stations are arranged along the transport path. A workpiece can be successively transported to different work stations of the honing machine by moving the transport system. If a work station is assigned at least one processing unit for performing a processing operation on the workpiece that changes the workpiece (e.g. a honing unit for honing, a drilling unit for drilling, a deburring unit for deburring, etc.), the work station can also be referred to as a processing station. Non-machining work operations are also possible, e.g. a measuring station for carrying out measurements on workpieces, or a charging station.

The transport system is preferably designed as a circulating transport system for transporting workpieces on a circulating transport path. The circulating transport path is preferably closed in the direction of rotation, but this is not mandatory. A machine-internal transfer along a circulating transport path makes it possible to get by with a single loading station for loading and unloading the workpiece holders. In contrast to transfer machines, it is possible for the workpieces to leave the honing machine at the same point at which they were fed to the honing machine. This facilitates loading and unloading and in particular also the coupling of the honing machine to an external conveyor system. There can also be two charging stations different positions can be provided along the transport path, for example one for loading and another for unloading the circulating transport system.

Some advantages of the claimed invention can in principle also be used if, instead of the circulating transport system for transporting workpieces on a, for example, circular circulating transport path, a linear transport system is used for transporting workpieces on a straight transport path. As with a transfer machine, the workstations can also be in series with one another.

With the help of an external conveyor system, the honing machine can be linked with other honing machines and / or with other processing machines (e.g. fine boring machines) to create a production system. The arrangement can be used in combination with different loading and unloading concepts, e.g. with a gantry loader with a horizontally and vertically movable gripper arm, with a loading robot and / or with a pendulum slide.

A honing unit carried by a horizontal slide can be positioned in the horizontal direction in such a way that a bore of a workpiece, which has been transported near or into a working position or machining position of the honing station with the aid of the transport system, can be honed by means of a honing tool carried by the honing spindle . If the transport system is set up in such a way that a workpiece is transported directly into a working position or machining position of the honing station with the aid of the transport system, the functions of workpiece transport and workpiece positioning are implemented by the transport system and no separate relocation is required. It is also possible to separate the functions of workpiece transport and workpiece positioning. It is then sufficient if the workpiece is transported into the vicinity of a working position or processing position with the aid of the transport system in such a way that the workpiece is then brought into the desired working position or processing position by a simple further operation.

A special feature is that the horizontal slide carries a lifting slide which can be moved in a vertical direction in a numerically controlled manner by means of a lifting slide drive. The honing machine thus has a further machine axis which can be controlled via the control unit of the honing machine and which can bring about a controlled lifting movement of the lifting slide. The lifting carriage carries further functional components of the honing machine, namely a counter-holder device and a tool magazine with several workpiece holders for receiving one honing tool each. According to another formulation, the solution can possibly also be described in such a way that the lifting carriage carries a counter-holder device with an integrated tool magazine. According to another formulation, a tool magazine which can be moved vertically by means of the lifting carriage is provided, which can be viewed as a component of a vertically movable counter-holder device.

These devices can be moved horizontally together with the honing unit by means of the horizontal slide. With the aid of the lifting slide, a vertical movement independent of the movements of the honing spindle can be carried out. The counter-holder device and the tool magazine offer further important functions of the honing process, which are attached to the horizontal slide in a spatially compact form and can be moved or positioned together with the honing unit by moving the horizontal slide.

The counterholder device is designed in such a way that, if required, it can absorb machining forces directed vertically upwards during honing. With the help of the lifting carriage, the counter-holder device can be moved parallel to the spindle axis, i.e. in the vertical direction, independently of the honing spindle and, if necessary, can be placed on the workpiece for machining the workpiece with a predetermined contact force in order to keep it free of play in the vertical direction (contact force close to zero) or hold down with a certain pressure if necessary. This enables the use of workpiece holders that do not have their own clamping device to secure the workpiece against lifting off during honing. In this way, trouble-free honing without lifting the workpiece from the workpiece holder is ensured in any case. The counter-holder device is available; it does not necessarily have to be used in every machining operation.

Through the integration of a horizontally moving tool magazine on the horizontal slide, the tool change function can be permanently positioned in close proximity to the honing unit or the honing spindle. A tool changing device with a tool magazine attached separately from the honing unit can therefore be dispensed with. The horizontal traverse path of the horizontal slide can thus be designed to be significantly shorter than with conventional honing machines, on which an external tool change was approached with the help of the horizontal slide (see for example Fig. 2 in the WO 2013/117482 A1 ). The length of the travel path of the horizontal slide only needs to be large enough to provide all of the horizontal movements required for machining a workpiece and all travel paths required for adapting the honing machine to different tool dimensions. The travel path can be a maximum of 500 mm, for example. If all the required travels are relatively short, it is possible to use the honing machine in each direction in which a horizontal slide is moved to be kept relatively short or compact.

Different solutions are possible for the design of the tool magazine. The tool magazine can be designed, for example, as a linear magazine. In preferred embodiments, the tool magazine is designed as a round magazine. In this way, a compact design with a favorable ratio between the number of available tool holders and the lateral dimensions of the tool magazine can be achieved. The round magazine can for example have an annular arrangement with four to twelve tool holders, in particular with six or eight tool holders.

In a further development, workpiece holders of the round magazine lie on a pitch circle which runs through the extension of the spindle axis. In this case, simply by rotating the round magazine around a vertical magazine axis of rotation with the aid of a magazine drive, one of the workpiece holders can optionally be brought into a tool change position that is an extension of the spindle axis.

In one embodiment it is provided that each of the workpiece holders has a vertical through opening for passing a honing tool through and a tool holding device for holding a honing tool in the through opening, the tool holding device being switchable between a holding configuration and a release configuration. The changeover can be carried out manually or automatically using a controlled actuator, as required.

In some embodiments, the tool magazine is equipped with further devices for additional functionalities. In some embodiments, a centering device for centering the honing tool for insertion into a bore to be machined is assigned to each of the workpiece holders. The centering device can have a preferably diameter-dependent flushing ring which, in addition to the centering function, also has the function of the controlled supply of cooling lubricant into the bore during the honing process. A centering and flushing ring can thus be provided. It is also possible to configure a centering device as a conical centering.

In many cases, honing tools are equipped with components of a measuring system for measuring the bore before and / or during and / or after a honing operation. Often it is a pneumatic bore measuring system with one or more measuring nozzles attached to the honing tool, which enable robust diameter measurement or Allow shape measurement of the bore with high accuracy. In some embodiments, each of the workpiece holders is assigned at least one reference ring for referencing the bore measuring system of the honing tool. This makes it possible to reference the bore measuring system at suitable times on a reference ring with an exactly known inside diameter in order to ensure high measuring accuracy in the long term.

In order to optimize the counter-holding function of the vertically movable assembly, at least one pressure element for placing on the top of the workpiece can be attached to each of the tool holders at an end on the workpiece. The pressure elements can be, for example, workpiece-dependent pressure rings or other, possibly exchangeable pressure pieces. A pressure element can be made of an elastic, somewhat flexible material, such as hard rubber or plastic, which enables it to be pressed onto the workpiece in a particularly gentle manner. Pressure elements made of metal, e.g. steel or a softer metal, such as aluminum, are also possible. Pressure elements are functional components of the counter holder device and offer at least one contact surface for placing on the top of the workpiece.

There are different design options for the support structure. The support structure can, for example, have two, three, four or more stands, which are arranged on and / or on the machine base in such a way that they lie outside the transport path and the work space between the stands is freely accessible from the side (see e.g. WO 2013/117482 A1 ).

In one embodiment with a circulating transport system, the support structure has an inner column and the circulating transport system is designed for transporting workpieces on a transport path running around the inner column. This ensures good accessibility to the area of the transport path from all sides. The term “column” here generally stands for a free-standing, load-bearing, inherently stable assembly that can consist of a single component or be composed of several interconnected components. The height measured in the vertical direction is usually several times greater than the cross-sectional dimension of the inner column. The carrying function for the components attached is essential. This carrying function can be the main function of the inner column, so that it can be optimized for the carrying function. The inner column can be formed, for example, by a tube with a hollow interior, as a result of which a high level of stability and load-bearing capacity can be achieved with a comparatively moderate weight and use of material. The tube can be a cylindrical tube (with circular Cross-section), other cross-sectional shapes, such as polygonal shapes, such as a triangular, quadrangular, in particular square, or a hexagonal (hexagonal) cross-sectional shape are possible. The inner column can also have one or more T-beams or one or more double T-beams or be formed by such a component. The inner column can have a torsion-resistant strut construction that can be open or clad on the outside. The inner column can have a plurality of column sections stacked on top of one another, which are detachably or firmly connected to one another.

In addition to the inner column, there may be a second column, e.g. a column arranged outside the transport path, which also serves as a support for the machine head and takes up part of the load.

In order to enable high productivity, the honing machine preferably has two or more work stations which are designed as a honing station. In one embodiment, the honing machine has at least three work stations which are designed as honing stations. In particular, exactly three honing stations can be provided. In one embodiment, a first honing station is arranged on a first side, a third honing station is arranged on a third side diametrically opposite to the first side and a second honing station is arranged on the transport path between the first and the third honing station on a second side. If three sides of the honing machine are equipped with honing stations, a particularly space-saving arrangement of a large number of honing units is possible.

Each of the honing stations preferably has a horizontal slide and each of the honing units has the units (lifting slide, counterholder device, tool magazine) that can be moved together with a honing unit.

Honing stations are possible which have only a single honing unit and, accordingly, only a single honing spindle. Embodiments in which at least one honing station has two or more honing units which can work simultaneously can offer higher productivity. In some embodiments, three honing stations, each with two honing units, are provided, so that the honing machine is a six-spindle honing machine. This makes it possible to create a good compromise between high productivity on the one hand and a compact design on the other hand.

There are different ways of designing a circulation transport system. Some embodiments are characterized in that the circulating transport system has a rotary table that can be rotated about a vertical rotary table axis and several Has workpiece holders which are arranged offset from one another in the circumferential direction at a radial distance from the rotary table axis such that a workpiece held in a workpiece holder can be transported to different work stations of the honing machine one after the other by rotating the rotary table. In some variants, the rotary table can be moved vertically between a lower position and an upper position by means of a lifting drive, so that the rotary table is designed as a lifting rotary table. Variants without a lifting drive are also possible.

Other circulation transport systems that can be used in the context of the honing machine are included in the utility model DE 20 2016 002 857 U1 described, the disclosure content of which is made part of the content of the present description.

The disclosure also relates to a production system with several processing machines for processing a workpiece and with a conveyor system for conveying workpieces to and from the processing machines. At least one of the processing machines is a honing machine according to the claimed invention.

For loading and unloading the transport system of the honing machine in the area of a loading station of the honing machine, for example at least one of the following devices can be provided: a portal loader with a horizontally and vertically movable gripper arm; a loading robot; a pendulum slide.

BRIEF DESCRIPTION OF THE DRAWINGS

• Fig. 1 zeigt eine schrägperspektivische Ansicht einer Ausführungsform einer Honmaschine mit Innensäule;
• Fig. 2 zeigt eine Draufsicht der Honmaschine in Fig. 1;
• Fig. 3 zeigt eine isometrische Ansicht einer Baugruppe mit Gegenhaltereinrichtung und Werkzeugwechselmagazin gemäß einer Ausführungsform;
• Fig. 4 zeigt einen Längsschnitt durch die Baugruppe aus Fig. 3; und
• Fig. 5 zeigt eine schrägperspektivische Ansicht auf die Unterseite des Werkzeugmagazins der Baugruppe.

Further advantages and aspects of the invention emerge from the claims and from the following description of preferred exemplary embodiments of the invention, which are explained below with reference to the figures.

• Fig. 1 FIG. 11 shows an oblique perspective view of an embodiment of an inner column honing machine; FIG.
• Fig. 2 FIG. 13 shows a top view of the honing machine in FIG Fig. 1 ;
• Fig. 3 shows an isometric view of an assembly with counterholder device and tool change magazine according to an embodiment;
• Fig. 4 shows a longitudinal section through the assembly from Fig. 3 ; and
• Fig. 5 shows an oblique perspective view of the underside of the tool magazine of the assembly.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 FIG. 10 shows an oblique perspective view of a honing machine 100 according to an embodiment from its loading and unloading side. Fig. 2 Figure 10 shows a top view of the honing machine. The honing machine has three honing stations 160-1, 160-2, 160-3, each with two independently controllable honing units and is set up for the purpose of honing the cylinder bores of workpieces W in the form of cylinder crankcases in several different honing operations (e.g. pre-honing, intermediate honing and finish honing) edit completely.

The 6-spindle honing machine has a rectangular machine base 110 which carries all mechanical components of the honing machine. In a first direction of the honing machine (corresponding to the x-direction of the machine coordinate system MKS, also referred to as the longitudinal direction), the machine base has a length which is essentially the width in the second direction orthogonal to the first direction (corresponding to the y-direction of the machine coordinate system, also referred to as the width direction or the transverse direction). The width of the machine base can for example be between 1800 mm and 3000 mm. The design, which is narrow in the width direction, allows the completely pre-assembled machine base to be transported using conventional means of transport, for example by truck or rail vehicle.

A vertical column, which is referred to here as the inner column 150, is mounted on the machine base approximately centrally between the sides running in the x-direction. The inner column 150 forms a central support structure or carrier structure of the honing machine and is designed to be correspondingly stable and torsion-resistant. In the exemplary embodiment, the inner column 150 is essentially formed by a circular cylindrical steel tube of suitable wall thickness. To achieve sufficient load-bearing capacity, the diameter of the inner column is usually 500 mm or more, for example in the range from 700 mm to 800 mm. The wall thickness can for example be in the range from 5 mm to 20 mm. The height of the inner column measured in the vertical direction (z-direction) is a multiple of the cross-sectional dimensions and can be, for example, in the range from 800 mm to 2000 mm. The In the example shown, the cylindrical outside of the inner column does not carry any mechanical functional units of the honing machine, in particular no machining units.

In the area of the upper end of the inner pillar 150, the machine upper part 120 of the honing machine is attached to the inner pillar, e.g. by means of an end flange connection. The machine head is arranged at a vertical distance of e.g. 800 mm to 2000 mm) above the machine base and is supported exclusively by the inner column 150.

The upper machine part 120 of the exemplary embodiment has an approximately cuboid shape and has a width in the y-direction which is slightly larger than the diameter of the inner column 150, but less than twice this diameter. The length in the x direction is just as great, so that the machine head has an essentially square cross section (in the xy plane) (cf. Fig. 2 ). In this example, the inner column 150 and the upper machine part 120 mounted on it form a T-shaped arrangement that is symmetrical to the central longitudinal axis of the inner column in such a way that the center of gravity of the upper machine part 120 lies above the inner column essentially on its central longitudinal axis.

The area between the bottom of the machine head 120 and the top of the machine base 110 contains the working space of the honing machine. Since the upper part of the machine is supported exclusively by the inner column 150 arranged at a distance from the edge of the machine base, the working space in this example is in principle accessible from all sides for an operator or for operating units.

The six independently controllable honing units 180-1, 180-2, 180-3, 180-4, 180-5 and 180-6 of the honing machine are carried by the machine head 120. The structure of a honing unit is described below with reference to the honing unit 180-1.

The honing unit 180-1 comprises a headstock 182, which serves as a bearing for the honing spindle 184 which is guided in the headstock with a vertical spindle axis. The rotation of the honing spindle around the spindle axis is effected by a rotary drive. A stroke drive causes the vertical movements of the honing spindle, which run parallel to the spindle axis, when the honing tool 185 is inserted into the bore to be machined or when the honing tool is withdrawn from this bore. The honing tool is coupled to the honing spindle in a double-articulated manner by means of a drive rod 186. The lifting drive can be controlled during the honing process so that the honing tool is within the bore of the Workpiece executes a vertical back and forth movement according to the desired honing parameters.

The honing unit 180-1 has a feed system which comprises two feed devices that can be operated independently of one another in order to be able to control honing tools with double expansion, if necessary. Since the structure of double-expanding delivery systems is known per se, a detailed description is dispensed with here.

The honing unit 180 - 1 is mounted on a horizontal slide 190 which is carried by the machine head 120. The horizontal slide runs on a pair of guide rails 192 which are mounted vertically one above the other on a side surface of the machine head 120 running parallel to the first direction (x direction). The linear direction of travel of the horizontal slide of the first honing station thus runs in the longitudinal direction (x-direction) of the honing machine. The slide movement is driven by a horizontal slide drive with a servomotor that drives a ball screw spindle that runs parallel to the guide rails and on which sits a spindle nut that is attached to the underside of the base plate of the horizontal slide. Other drive concepts are also possible, for example rack and pinion drives or belt drives.

At the in Fig. 1 On the left side of the machine head, two identically constructed honing units 180-1, 180-2 are mounted next to each other. These belong to the first honing station 160-1. The honing units can be moved horizontally controlled independently of each other. This can be achieved, for example, by mounting the honing units on independently movable horizontal slides. These two horizontal carriages can run on the same guide rails 192. A separate drive can be provided for each of the carriages. It is also possible that a first horizontal slide running on the guide rails carries both honing units, one of the honing units being fixedly mounted on this horizontal slide and this horizontal slide carrying guide rails for a separate second horizontal slide to which the other honing unit is attached. As a result, the lateral distance between the spindle axes of the two honing units carried by the first horizontal slide can be adjusted. Another possibility is that the honing units are mounted on independently movable horizontal carriages that run on the same guide rails 192, these horizontal carriages being coupled to one another at an adjustable distance from one another. A first drive is then used to move the horizontal slides together along the guide rails, while a second drive is used to adjust the spindle distance in a numerically controllable manner.

On the back opposite the loading and unloading side there is a corresponding arrangement with two honing units 180-3 and 180-4 that can be moved linearly and horizontally independently of one another. These can be moved in the y-direction (transverse direction) and belong to the second honing station 160-2.

On the other longitudinal side diametrically opposite the first honing station there is a corresponding arrangement with two further honing units 180-5, 180-6 which can be moved horizontally and linearly independently of one another. These can be moved in the x direction (longitudinal direction) and belong to the third honing station 160-3.

A transport system 130 in the form of a circulating transport system 130 for transporting workpieces on a transport path 132 running around the inner column 150 is arranged on the machine base 110. In the example, the circulating transport system comprises a rotary table which has an annular device carrier running around the inner column and can therefore also be referred to as a ring table. The rotary table can be rotated indefinitely about a vertical rotary table axis running coaxially with the longitudinal center axis of the inner column and can be fixed in predeterminable rotary positions, so that it can also be referred to as a rotary indexing table.

The rotary table or the device carrier of the rotary table has an inner ring 133 concentric to the rotary table axis or to the longitudinal center axis of the inner column, from which radially elongated, plate-shaped support arms 134 protrude horizontally at four positions offset by 90 ° in the circumferential direction. Each support arm has a workpiece holder 135 on its upper side.

In addition to the rotary drive, which causes the rotation around the rotary table axis, the ring table or rotary table 130 also has a lifting drive in order to raise the device carrier of the ring table in the vertical direction (z-direction, parallel to the rotary table axis) controlled by the machine control of the honing machine or lower it. The rotary table is thus designed as a lifting rotary table. In the example, it is used to transport the workpiece in the manner of a circular stepping stroke.

At each of the work stations, that is to say at each of the honing stations as well as at the loading station, a machine-fixed workpiece support device 170 (see loading station 140) is attached to the machine base 110. The four workpiece support devices have an identical structure. A workpiece support device has two vertical, substantially plate-shaped support elements 172-1, 172-2 which are laterally spaced from one another. The free Upper end faces of the support elements serve as support surfaces on which the workpiece W (cylinder crankcase) can be placed with its underside. The free upper sides of the support elements serve as second support structures for supporting the workpiece in second support areas on the underside of the workpiece, these second support areas being on the longitudinal ends of the cylinder crankcase. The second support structures have indexing devices for receiving a workpiece (cylinder crankcase) in the correct position on the workpiece support devices. These indexing devices (index bolts / index bores) are designed to correspond to indexing devices on the underside of the workpiece, so that when a workpiece is set down, it automatically moves into the machining position with high positioning accuracy with the help of the indexing devices. The workpiece can be clamped in the machining position (e.g. at each of the honing stations) using suitable clamping devices. In the example case, separate clamping devices are dispensed with, since there is a counter-holder device 330, which will be explained later and which prevents the workpieces from being lifted off during processing.

The honing machine 100 has four work stations arranged along the circular transport path 132 of the rotary transport system. The rotary table serves as a machine-internal transfer system in such a way that a workpiece held in a workpiece holder of the rotary table can be transported to the different work stations of the honing machine one after the other by rotating the rotary table. In the illustrated configuration of Fig. 1 the workstations arranged on the visible front side of the machine base is a loading station 140 for loading and unloading the rotary transport system 130 or the rotary table. In the example of Fig. 1 the machine head 120 on the side of the charging station 140 is so short that the transport track 132 is accessible from above (cf. Fig. 2 ). For example, a portal gripper can be used for loading and unloading. Loading and unloading from the front, for example by means of a loading robot or a pendulum slide, is also possible.

Each of the six honing units 160-1 to 160-6 has an assembly 300 which has a lifting slide 310 carried by the associated horizontal slide, which can be moved in the vertical direction (z-direction) with the aid of an electromotive lifting slide drive 312. The lifting slide 310 carries a counter-holder device 330 (which can be moved vertically by means of the lifting slide) and a tool magazine 350 integrated therein with a plurality of tool receptacles 360, each of which is designed to hold a single honing tool. An embodiment of the assembly is shown in Fig. 3 shown in an oblique perspective, Fig. 4 shows a longitudinal section through the assembly, Fig. 5 shows an oblique perspective view of the underside of the tool magazine.

The assembly 300 includes a spacer bracket 320 which has the shape of a lying U with an opening on one side and which is used to rigidly connect the assembly 300 to the honing unit and / or to the horizontal slide. The spacer bracket can, for example, be detachably fastened by means of screws to the spindle box of the honing unit and / or to the horizontal slide carrying the honing unit. In the example, the spacer bracket is attached directly to the horizontal slide below the headstock. It is also possible to implement the function of the spacer bracket by means of a horizontal mounting plate or the like that is firmly connected to the horizontal slide. This can e.g. be welded to the horizontal slide or formed in one piece with it.

A lifting bracket 322 with a U-shaped cross-section is attached to the underside of the spacer bracket and has a pair of vertically extending guide rails 314 on its inside, on which the guide shoes of the lifting carriage 310 are guided. The servomotor of the lifting carriage drive 312, which is fastened with a vertical axis in the area of the spacer bracket 320, drives a vertically aligned ball screw spindle on which a spindle nut runs, which is fastened between the guide shoes on the facing side of the lifting carriage 310. A linear drive can also be used as an alternative.

At its lower end, the lifting carriage 310 has a horizontal mounting plate 316 on which the tool magazine 350 is rotatably mounted about a vertical axis of rotation. The rotation of the tool magazine is effected by means of a magazine drive 352 equipped with a servomotor, which is mounted on the mounting plate with a vertical axis. The rotary bearing and the drive for the tool magazine are mounted in the area of the mounting plate 316.

The tool magazine 350 is designed as a six-fold round magazine. The six mutually identical tool holders 360 lie on a pitch circle which runs through the extension of the spindle axis 187, so that one of the tool holders can be brought into a working position centered on the spindle axis by rotating the round magazine. Each of the tool receptacles 360 has a vertical through opening for guiding a honing tool through, as well as a tool holding device 365 which can be switched between a holding configuration and a release configuration. In the holding configuration, a honing tool that has been received is held within the through opening and secured against falling. In the release configuration, the honing tool can when it is attached to the honing spindle or the drive rod 186 is coupled, removed upwards or carried out downwards towards the workpiece.

The tool magazine has a central support shaft 361, which is coupled with a vertical axis directly to the output shaft of the magazine drive 352. At the lower end of the support shaft 361 is a solid, round base plate 362 with six through bores for the honing tool to pass through. At a distance above the base plate there is a central ring 363 running in a ring around the support shaft with six through openings at the locations of the tool holders. The vertical distance between the base plate and the middle plate is maintained using spacers, among other things. At a distance above the middle ring 363 is a device ring 366 which has six identical ring segments, one of the ring segments belonging to each tool holder. Each of the ring segments carries movably mounted components of a pliers-like tool holding device 365. Each workpiece holding device has a locking device for securing the honing tool held in the tool holder. The locking device of that tool holding device which is in the working position aligned with the spindle axis can be automatically unlocked with the aid of a tool unlocking device 370. A pneumatic drive 372 of the tool unlocking device is mounted next to the magazine drive 352 on the lifting slide 310 and acts on unlocking elements of the tool holding device 365 via a rocker arm.

A flushing and centering ring 380 is attached to the underside of the base plate 362 for each tool holder and carries an exchangeable, workpiece-dependent pressure ring 385 on its end face facing the workpiece. The flushing rings are supplied with cooling lubricant in sections via flexible cooling lubricant hoses 382 hanging downwards in a U-shape, which compensate for the up and down movement of the vertically movable assembly 300. In the area between the base plate 362 and the middle ring 363, a sleeve-shaped reference ring 390 is attached for each tool holder, which has a cylindrical inner contour with an exactly known inner diameter and which serves as a reference element for a tool-internal dimension measuring system.

The honing machine 100 can be used as follows, for example. A workpiece that has not yet been machined (cylinder crankcase) is loaded into the honing machine in a loading operation. Here, the lifting rotary table 130 is in its lowering position and the workpiece support device on the loading station 140 is free. The workpiece can, for example, through a window 142 located next to the machine head 120 in the Machine casing above the loading station lowered onto the workpiece support device by means of a portal loader or from the front by an in Fig. 1 dashed door, can be loaded in the horizontal direction.

The workpiece is then transported to the first honing station 160-1 in a circular step stroke operation. This operation comprises lifting the rotary table 130 upwards so that the workpiece is lifted off the workpiece support device by means of the support arm, indexing the rotary table clockwise by 90 ° until the cylinder crankcase is above the workpiece support device of the first honing station 160-1 is arranged, and a lowering of the lifting rotary table down, wherein the workpiece is placed on the workpiece support device of the first honing station. The workpiece is then in its machining position. The cylinder bores arranged in series with one another are then arranged in such a way that all cylinder axes lie in a common tangential plane on a reference circle which is concentric to the axis of rotation of the rotary table. The spindle axes of the two honing units 180-1, 180-2 of the first honing station 160-1 are also located in this tangential plane and can be moved in the x-direction within this tangential plane by moving the horizontal slide 190, so that different cylinder bores for machining with one honing spindle can be approached.

First, two cylinder bores are machined in parallel using the two honing units 180-1, 180-2. For this purpose, the honing units are positioned vertically above these cylinder bores. Then the assemblies of the counter holder device 330 with integrated tool magazines are lowered by moving the respective lifting carriage downwards in the direction of the workpiece until the pressure pieces at the lower end of this unit hit the upper side of the workpiece. As a result, the workpiece is secured against lifting off the workpiece support device during the honing process with the aid of the counter holder device 330.

The honing process then takes place by inserting the honing tools into the bores to be machined and then carrying out the honing operation. The insertion operation is supported by the centering and flushing rings attached to the rotary table of the tool magazine. The centering and flushing rings also support the supply of cooling lubricant into the bores during machining.

After finishing the machining of the first pair of cylinder bores, the assemblies with the tool magazine and counter-holding device as well as the honing spindles are raised independently of one another, but coordinated in time, so that the Honing tools are pulled out of the cylinder bores. Then the horizontal slide is moved in the x-direction so that the two honing spindles are now over the next two cylinder bores to be machined before they are machined. For machining, the lifting slide is then lowered again to make the workpiece free of play in the vertical direction before the honing tools are inserted into the cylinder bores. After completing this honing operation, the honing process is completed at the first honing station. The workpiece is released by moving up the counter holder device with integrated tool magazines and can now be lifted off the workpiece support device by lifting the rotary table.

For onward transport to the second honing station 160-2, the lifting rotary table is raised, advanced 90 ° clockwise and then lowered again so that the workpiece sits on the workpiece support device of the second honing station 160-2. The honing operation in the second honing station 160-2 then takes place analogously, as is the onward transport to the third honing station 160-3 and the honing operation there. After completing the honing process at the third honing station 160-3, the now finished workpiece is transported back to the loading station 140 by lifting the rotary table and indexing it through 90 °, from where it is then removed.

The honing machine allows the parallel machining of two cylinder bores at each honing station. By combining a total of six honing units at three honing stations that can be approached one after the other, a sequence of pre-honing, intermediate honing and finish honing is possible in a relatively short machining time.

If a tool change is to be carried out, for example when a honing tool is worn or when changing over to a different workpiece type or another honing operation, a tool change can be carried out either automatically or manually in a simple manner. For this purpose, the tool magazines traveling with the honing units can be equipped with up to six optionally exchangeable honing tools. For a tool change, the honing tool that is coupled to the drive rod and to be replaced is first positioned by moving the honing spindle vertically so that the honing tool can be gripped and held by means of the tool holder device 365. Then the tool release is actuated and the connection between the drive rod and the honing tool is released by turning the drive rod in relation to the honing tool. Then, by rotating the tool magazine, the tool holder that carries the honing tool to be inserted is brought into the working position in alignment with the honing spindle. The coupling to the drive rod then takes place also automatically, with the honing tool being released by the tool holder device after the coupling is complete and can then be used.

It should be noted that the tool change function is possible without moving the tool magazine vertically. The integration of the tool magazine and the counterholder device on the vertically movable lifting carriage means that a tool magazine with a relatively small diameter can be used, so that the tool change function of the 6-fold changer can be integrated with compact dimensions in the lateral direction in the horizontally movable assembly.

Since the tool change function is integrated in the horizontally movable assemblies, there is no need for an external tool changer. As a result, the honing units only have to be movable in the horizontal direction to such an extent that, for all types of workpiece to be machined, all bores can be reached with one honing spindle or one honing unit. In the exemplary embodiment shown, the required traverse paths in the horizontal direction for all three honing stations are less than 500 mm. In this way it can be achieved that, despite the provision of two honing units on three sides of the machine head, a honing machine with very compact external dimensions (typically less than 3 m in the x-direction and y-direction) can be implemented.

Claims (15)

1. Honing machine (100) for carrying out honing operations on at least one borehole in a workpiece (W), in particular for honing processing of cylinder boreholes in a cylinder crank casing, having:

   a machine base (110);

   a supporting construction assigned to the machine base;

   a machine upper part (120) borne by the supporting construction, which machine upper part is arranged at a distance above the machine base;

   a transport system (130) for transporting workpieces (W) on a transportation path (132);

   a plurality of work stations (140, 160-1, 160-2, 160-3) arranged along the transportation path, wherein a workpiece is transportable successively to different work stations of the honing machine by locomotion of the transport system,

   wherein at least one of the work stations is a honing station (160-1, 160-2, 160-3), the honing station has at least one horizontal carriage (190) which is supported by the machine upper part (120) and displaceable in a horizontal direction, and

   the horizontal carriage bears at least one honing unit (180-1, 180-2, 180-3, 180-4, 180-5, 180-6) which has a honing spindle (184) which can move about a vertical spindle axis (187) in rotation and back and forth in parallel to the spindle axis,

   characterized in that

   the horizontal carriage (190) bears a lifting carriage (310) which is displaceable in a vertical direction,

   wherein the lifting carriage bears a counter-support device (330) and a tool magazine (350) having multiple tool holders (360), each for receiving one honing tool.
2. Honing machine according to claim 1, characterized in that the tool magazine (350) is a rotary magazine.
3. Honing machine according to claim 2, characterized in that the rotary magazine has an annular arrangement with four to twelve tool holders (360), in particular with six or eight tool holders.
4. Honing machine according to claim 2 or 3, characterized in that some or all tool holders (360) of the rotary magazine are located on a pitch circle which extends across the prolongation of the spindle axis (187).
5. Honing machine according to any one of the preceding claims, characterized in that each of the tool holders (360) has a vertical through opening (361) for passing a honing tool through and a tool holder device (365) for holding a honing tool in the through opening, wherein the tool holder device is adaptable between a holding configuration and a release configuration.
6. Honing machine according to any one of the preceding claims, characterized in that each of the tool holders (360) has assigned to it, on a workpiece-side end, at least one pressure element (385) for placing onto an upper side of the workpiece.
7. Honing machine according to any one of the preceding claims, characterized in that each of the tool holders (360) has assigned to it at least one of the devices below:

   a centering device for centering the honing tool for insertion into a borehole to be processed;

   a flushing ring for assisting of the supply of cooling lubricant into the borehole;

   a reference ring (390) for referencing a borehole measuring system of the honing tool.
8. Honing machine according to any one of the preceding claims, characterized in that the horizontal carriage (190) is attached to a lateral surface of the machine upper part.
9. Honing machine according to any one of the preceding claims, characterized in that the transport system is a circulating transport system (130) for transporting workpieces (W) on a circulating transportation path (132) which is preferably closed in the peripheral direction, wherein preferably the supporting construction has an inner pillar (150) and the circulating transport system (130) for transporting workpieces (W) is disposed on a transportation path (132) extending around the inner pillar.
10. Honing machine according to claim 9, characterized in that the circulating transport system has a round table (130) which can rotate about a vertical round table axis and has a plurality of workpiece receptacles (135) which are arranged offset with respect to one another in a circumferential direction at a radial distance from the round table axis in such a way that a workpiece which is received in a workpiece receptacle can be transported successively to different work stations (140, 160-1, 160-2, 160-3) of the honing machine by rotating the round table.
11. Honing machine according to claim 10, characterized in that the round table (530) can be displaced vertically between a lower position and an upper position by means of a lifting drive such that the round table is configured as a lifting round table.
12. Honing machine according to any one of the claims 9 to 11, characterized in that on each workstation a stationary workpiece supporting device (170) for receiving a workpiece in a processing position is provided, wherein the workpiece supporting device is adapted to the region of the workpiece receptacle of the round table (130) such that a workpiece received in a workpiece receptacle of the round table is transferable from the workpiece receptacle of the round table to the workpiece supporting device by lowering the round table in the direction towards the lower position and is transferable from the processing position on the workpiece supporting device into the workpiece receptacle of the round table by raising the round table in the direction towards the upper position.
13. Honing machine according to any one of the preceding claims, characterized in that the honing machine (100) has at least three work stations which are honing stations (160-1, 160-2, 160-3), wherein preferably the honing machine has exactly three honing stations (160-1, 160-2, 160-3).
14. Honing machine according to claim 13, characterized in that a first honing station (160-1) is disposed on a first side, a third honing station (160-3) is disposed on a third side diametrically opposed to the first side, and a second honing station (160-2) is disposed on a second side on the transportation path between the first and the third honing stations.
15. Honing machine according to any one of the preceding claims, characterized in that at least one honing station (160-1, 160-2) has two or more honing units which can operate simultaneously, wherein preferably exactly three honing stations (160-1, 160-2), each with exactly two honing units, are provided.

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