DE102018131145A1 - Digitally controlled flexible guide bush - Google Patents

Abstract

Flexible guide bush for guiding a material bar subject to a material processing operation, with a guide tongs receptacle, a guide tongs arranged axially displaceably in the guide tongs receptacle, a pneumatically or hydraulically driven actuator set up for axially moving the guide tongs, and a control device for regulating the pneumatic or hydraulic acting on the actuator Pressure, characterized in that the control device is set up as a function of at least one property of the guide tongs, the material bar and / or the material processing operation of the material bar for setting a maximum pneumatic or hydraulic pressure acting on the actuator.

Description

The invention relates to a flexible guide bush for Swiss type automatic lathes. In particular, the invention relates to a flexible guide bushing for guiding a material bar subject to a material processing operation, with a guide tongs receptacle, a guide tongs axially displaceably arranged in the guide tongs receptacle, a pneumatically or hydraulically driven actuator set up for axial movement of the guide tongs, and a control device for regulating the on the Actuating pneumatic or hydraulic pressure.

Such a guide bush is already out of the DE 10 2017 105 872 A1 known.

As is known, the opening and closing of the guide pliers of such flexible guide bushings is carried out by a pneumatically or hydraulically moved actuator, in particular in the form of a piston. In the closed state, the pneumatic or hydraulic pressure applied to the piston determines the holding force imparted by the guide pliers and acting on the material rod. For this purpose, the pneumatic or hydraulic pressure acting on the piston, which is required for the holding function of the guide pliers, to be performed by hand, is set manually and checked with a pressure gauge. The guiding tongs are opened and closed by alternating switching of valves, which are controlled via the lathe control or the control panel of the lathe or via separate switches, whereby suitable pneumatically or hydraulically active media are used to generate the pressure acting on the piston . This procedure applies equally to guiding pliers designed for pressure or pulling pliers.

To perform the function of the flexible guide bushing, the required pressure acting on the actuator is set once when setting up the lathe according to the clamping force required for part production with rods as the starting material. In particular, the maximum pressure applied to the actuator is determined according to the machining step within the overall cycle of the production of a part that requires the highest clamping force.

Although the known guide bushes allow a substantially improved, in particular more precise machining of material bars by means of Swiss-type automatic lathes, in addition to the components of the lathe, the components of the guide bush are also subject to wear.

The object of the invention is therefore to create a low-wear flexible guide bushing of the type mentioned, which at the same time guarantees the highest processing speed and manufacturing quality with the least rejects, and enables safe operation and verifiability of the functions.

This object is achieved by the flexible guide bush with the features of claim 1. The subclaims give advantageous refinements of the invention.

The applicant has determined that the height of the clamping force of the guiding tongs, which is defined for the entire passage of several successive processing steps, is not absolutely necessary for all processing steps. For example, the constant application of the maximum clamping force required for a specific machining step in those machining steps in which, for example, a lower clamping force would be sufficient and, for example, an advancement of the material rod is required, leads to greater wear of the guide pliers and to a slowing down of the machining process.

Conversely, in the case of the conventionally designed flexible guide bushes according to the prior art, there is also the case that the pressure has not been set sufficiently high or drops unnoticed during the machining process and the clamping force is therefore insufficient, as a result of which parts are manufactured outside of the required tolerances. In addition, there is also the case that the machine is started without the guiding tongs being closed and thereby being damaged.

The basic idea of the invention is therefore to create a flexible guide bush which ensures wear-reduced operation of the guide bush and which increases the machining speed and the quality of the production parts. In addition, an automated control of the function of the guide bush itself and in interaction with the lathe is made possible.

According to the invention, a flexible guide bush is therefore proposed for guiding a material rod that is subject to a material processing operation, which comprises a guide tongs receptacle, a guide tongs arranged axially displaceably in the guide tongs receptacle, a pneumatically or hydraulically driven actuator set up for the axial movement of the guide tongs, and a control device for regulating the on the Actuator acting pneumatic or hydraulic pressure, the Control device is set up as a function of at least one property of the guide tongs, the material bar and / or the material processing operation of the material bar for setting up a pneumatic or hydraulic pressure required for the respective processing step.

As is known, the pneumatically or hydraulically driven actuator effects the opening and closing of the guide pliers by displacing the guide pliers in the guide receptacle and, at the same time, determines the clamping force applied to the material rod.

The property of the guiding tongs, the material bar and / or the material processing process can in particular also describe a state of the respective object. It is conceivable that the degree of opening of the guide tongs is determined by means of suitable sensors and at the same time it is determined whether the guide tongs can be closed further or the smallest inner diameter has already been reached.

Overall, a plurality of sensors should therefore preferably be provided, with digitally working programmable signal processing, D / A converters, at least one proportional valve, particularly preferably a touch panel, a memory, at least one pressure meter and / or a plurality of valves being beneficial.

In particular, when using a plurality of different guide tongs, it can preferably be provided that by means of a memory a value assignment between the pneumatic or hydraulic pressure acting on the actuator and the resulting clamping force for each guide tongs used as the basis for setting and checking a maximum required acting on the actuator pneumatic or hydraulic pressure is used and stored in the control device.

The control device accesses the pressure gauge, pressure switch and proportional valves to set and control the maximum required pneumatic or hydraulic pressure acting on the actuator.

The control device thus preferably sets and controls a maximum required pneumatic or hydraulic pressure acting on the actuator with the aid of the aforementioned value assignment, a program and at least one of the properties (or the state). In particular, when the lathe or guide bush is in operation, a pressure is set which is less than or equal to the resulting maximum required holding force of the material rod during a material processing operation.

The control device sets and controls the maximum required pneumatic or hydraulic pressure acting on the actuator in small steps following the machining sequence and depending on at least one of the properties / state from the machine control and / or the production program.

At least one of the properties / state is present as a time and location-dependent variable in real time or is determined in real time and converted into a digital value and / or transferred from the machine control and / or the production program to the control device or entered directly and from the control device to Setting and checking a maximum required pneumatic or hydraulic pressure acting on the actuator.

Finally, the control device sets the maximum required pneumatic or hydraulic pressure acting on the actuator in such a way that the least wear of the guide bushing, the greatest possible machining speed and manufacturing quality and / or the least reject results.

Given the geometry of the guide tongs receptacle, the variable use of different guide tongs, different material bars and different material processing processes acting on the material bars results in a complex interplay of different factors, which cannot be met by setting a single predetermined maximum pressure acting on the actuator. According to the invention, however, by taking into account the properties, a pneumatic or hydraulic pressure which is respectively adapted to the system set up or to the respectively changed work situation can be set online in digital steps.

The at least one property of the guide pliers is preferably the minimum inside diameter of the guide pliers.

The at least one property of the material rod is furthermore preferably the hardness, the toughness, the elasticity, the coefficient of friction and / or the diameter of the material rod.

It is further preferred if the at least one property of the material processing operation is the type of material processing, the type of tool used for the material processing, which is directed radially through the tool used The force acting on the material bar and / or the force acting axially on the material bar by the tool used, and thus the required holding force of the material bar. It is most preferably provided that the diameter of the material rod is the diameter of a section of the material rod arranged in the guide bushing.

The flexible guide bush further preferably has a memory for storing properties of the data relating to the guide bush. This data can be, for example, a plurality of properties stored for different guide bushes. However, the memory can also be used (in addition) to store data ascertained during the operation of the guide bush about the state of the guide bush and the associated operating parameters. This makes it possible to monitor the function and wear of the guide bush and to intervene in a regulating manner if necessary.

In this context, the control device is preferably set up to output an alarm when a predetermined pneumatic or hydraulic pressure acting on the actuator is exceeded or not reached.

Finally, a lathe with a lathe control and a flexible guide bush according to the invention is also claimed, the lathe control being communicatively connected to the control device of the guide bush.

The coordination of the lathe and guide bush improves material processing and increases the safety of the personnel. In particular, it is provided that the lathe control does not allow the lathe to start if the guide tongs are not closed.

The invention is suitable for all types of flexible guide bushes, including guide bushes in which the guide pliers are designed as a double-cone guide pliers or as a pull guide pliers.

The advantage of the present invention is that by adjusting the pneumatic or hydraulic pressure acting on the actuator, the clamping force just required for the machining is used at any time. Since it is no longer necessary to set the clamping force that corresponds to the machining step within the cycle of manufacturing a part that requires the highest clamping force, the wear of the guide bush can be reduced.

• Der vorliegende Lösungsansatz besteht darin, eine digitalisierte Drucksteuerung des die Spannkraft herstellenden Mediums in Abhängigkeit von der jeweiligen Zerspanungsleistung bzw. ihren Parametern, z.B. entsprechend der jeweiligen Zerspanungsart, des Werkzeugeinsatzes, des Vorschubs und des effektiven Durchmessers während der einzelnen Bearbeitungsschritte im System Führungsbuchse/Drehmaschine zu implementieren.

The idea of the invention is explained below by way of example using a particularly preferred exemplary embodiment:

• The present approach consists in digitalized pressure control of the medium producing the clamping force depending on the respective cutting performance or its parameters, e.g. according to the respective type of cutting, the use of tools, the feed and the effective diameter during the individual machining steps in the guide bush / lathe system to implement.

Furthermore, the solution is to digitize the values and processes of all function-determining valves, actuators, sensors and monitoring devices to achieve automated control of the guide bush with regard to safety, time and quality.

This is achieved in that, instead of the pressure set by hand, a device is created, in particular in the form of an electronic control system, which is based on a fixed assignment of the pressures applied and the resulting clamping forces for each guide tongs used. This control device then communicates with the lathe control in such a way that the optimum pressures or clamping forces stored there for the individual machining steps are imported and converted into control signals for a particularly preferred proportional valve and thus the pressure acting on the actuator is infinitely variable and is adjusted accordingly to the machining requirements .

The electronic control device consists in particular of a programmable control relay, a D / A converter, a touch panel and, in addition to the proportional valve, also controls the solenoid valve and queries pressure switches and pressure monitors. If necessary, the machine operator can intervene directly via the control panel of the electronic control device and raise or lower the pressures at any time.

Alternatively, with the help of an extension in the lathe control software, the proportional valve and the solenoid valves of the guide bush can be accessed directly with the lathe control via a D / A converter by storing the optimum pressures or clamping forces for the individual machining steps in the parts production program of the lathe control. Here, too, the machine operator can intervene directly via the control panel of the lathe control and set the pressures up or down at any time.

The pressures or clamping forces with the associated machine commands as well as the commands for the valve control can be stored in the parts production program with the electronic control device or the software extension of the lathe control and can be called up for repeat parts and subsequent series. If necessary, changes can be entered in the control panel on the machine in the manufacturing process. Safety functions can also be stored, for example the machine cannot be started or is stopped when there is no pressure and the guiding tongs are not closed. Software routines can be implemented that check the function of the guide bush and automatically issue error messages, for example when the piston end position switch is triggered and the associated lack of tension in the guide or collet. At the same time, this error detection is a basis for assessing the state of wear in the ongoing manufacturing process.

The digitization of all values, processes and functions of the guide bush with the help of the electronic control device or the software enhancement of the lathe control enables not only easier operation and safety, but also repeatable setting of the guide bush depending on the optimal pressures stored for individual processing steps, both when guiding and when clamping the material bar to be processed. The guide bush can thus be integrated into the "Industry 4.0" technology and the higher-level production control technology.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102017105872 A1 [0002]

Claims (10)

Flexible guide bush for guiding a material bar subject to a material processing operation, with - a guide tongs receptacle, - a guide tongs arranged axially displaceably in the guide tongs receptacles, - a pneumatically or hydraulically driven actuator set up for the axial movement of the guide tongs, and - a control device for regulating the actuator acting pneumatic or hydraulic pressure, characterized in that the control device is set up as a function of at least one property of the guide tongs, the material bar and / or the material processing operation of the material bar for setting a maximum pneumatic or hydraulic pressure acting on the actuator. Flexible guide bush after Claim 1 , characterized in that the at least one property of the guide pliers is the minimum inner diameter of the guide pliers. Flexible guide bush according to one of the preceding claims, characterized in that the at least one property of the material bar is the hardness, toughness, elasticity, coefficient of friction and / or the diameter of the material bar. Flexible guide bushing according to one of the preceding claims, characterized in that the at least one property of the material processing operation, the type of material processing, the type of tool used for material processing, the force acting radially through the tool used on the material rod, the axial force through the tool used force acting on the material bar, the feed of the material bar and / or the maximum required holding force of the material bar. Flexible guide bush after Claim 2 , characterized in that the diameter of the material rod is the diameter of a section of the material rod arranged in the guide bushing. Flexible guide bush according to one of the preceding claims, characterized in that the guide pliers are a double cone guide pliers or a pull guide pliers. Flexible guide bush according to one of the preceding claims, characterized by a memory for storing properties of the data relating to the guide bush. Flexible guide bushing according to one of the preceding claims, characterized in that the control device is set up to output an alarm when a predetermined pneumatic or hydraulic pressure acting on the actuator is exceeded or not reached. Lathe with a lathe control and a flexible guide bush according to one of the preceding claims, wherein the lathe control is communicatively connected to the control device of the guide bush. Lathe after Claim 9 , characterized in that the lathe control is set to prevent the start of the lathe when the guide tongs are not closed.