DE3314318C1

DE3314318C1 - Measurement sensor with inductive measurement system for grinding machines

Info

Publication number: DE3314318C1
Application number: DE19833314318
Authority: DE
Inventors: Joachim Dipl.-Ing. 6000 Frankfurt Lankes
Original assignee: Diskus Werke Frankfurt am Main AG
Current assignee: Diskus Werke Frankfurt am Main AG
Priority date: 1983-04-20
Filing date: 1983-04-20
Publication date: 1984-10-04

Abstract

The invention relates to a measurement sensor with an inductive measurement system for fast measurement processes on continuously operating grinding machines, whereby the workpieces can be slid under the measurement sensors by a feeding device and scanned in quick succession and the measurement signals serve, after an electronic evaluation, for controlling the feeding systems of the grinding machine. The object of the invention in this case is to remedy the known deficiencies of the machine sensors with respect to lateral forces. This occurs according to the invention in that, when using a divided measurement sensor - front scanning finger and rear scanning finger - the front scanning finger is subjected to stepped axial elastic forces and that, behind the scanning tip, a predetermined fracture point is provided in the case of extreme stress to secure the inductive measurement system which follows. <IMAGE>

Description

Der Meßtaster für Schleifmaschinen nach dem Oberbegriff von Anspruch 1 gemäß der Erfindung kennzeichnet sich hierzu durch folgende Merkmalkombination: a) daß der vordere Taststößel unter Wirkung gestufter axialer Federkräfte steht und b) daß er in zwei hintereinanderliegenden Gleitlagern geführt ist zur Aufnahme der Seitenkräfte und Erzeugung einer Dämpfungsreibung und c) daß der hintere Meßstößel eine Vorhubeinstellschraube zur Verminderung der Hubbewegung in Tastlücken besitzt und durch die Trennung vom Taststößel nur axial ohne Seitenkräfte zu betätigen ist. The probe for grinding machines according to the preamble of claim 1 according to the invention is characterized by the following combination of features: a) that the front plunger is under the action of stepped axial spring forces and b) that it is guided in two plain bearings lying one behind the other for receiving the side forces and generation of damping friction and c) that the rear plunger has a pre-stroke adjustment screw to reduce the stroke movement in key gaps and can only be actuated axially without side forces due to the separation from the feeler plunger.

Durch die gestuften Federkräfte ist die Hubbewegung progressiv gedämpft und für extreme Überbeanspruchungen ist eine Sollbruchstelle mit austauschbarem Taststößel vorgesehen. Desweiteren kann mit der Vorhubeinstellschraube die mechanische Null-Stellung des induktiven Meßtasters optimal dem benötigten Meßbereich angepaßt werden, zum Vorteil einer Absenkbegrenzung der Stößel in Tastlücken. Der hintere Meßstößel des Tandem-Meßtasters wird somit nur axial belastet ohne Seitenkräfte, wobei das wertvolle induktive Meßsystem wesentlich geschützt wird. The stroke movement is progressively dampened by the stepped spring forces and for extreme overuse there is a predetermined breaking point with a replaceable Plunger provided. Furthermore, the mechanical Zero position of the inductive probe optimally adapted to the required measuring range to the advantage of limiting the lowering of the plunger in tactile gaps. Rear The measuring ram of the tandem probe is therefore only loaded axially without lateral forces, whereby the valuable inductive measuring system is substantially protected.

Wenn aus meßtechnischen Gründen, z. B. für empfindliche Werkstückoberflächen eine geringe Meßkraft erwünscht ist, so werden außer den Federkräften auch die Massenkräfte der bewegten Teile angepaßt durch Materialien geringen Gewichts, z. B. Titan, und großer Verschleißhärte an der Spitze, z. B. Borcarbid. Zur Vermeidung des Stick-Slip-Effektes bei den Taststößelgleitlagern werden vorzugsweise Trockengleitlager mit einem Stützskelett von Sintermetallen mit Kunststoffausfüllungen eingesetzt. If for metrological reasons, z. B. for sensitive workpiece surfaces If a low measuring force is desired, the inertia forces are also used in addition to the spring forces the moving parts adapted by low weight materials, e.g. B. Titan, and great wear resistance at the tip, e.g. B. boron carbide. To avoid the stick-slip effect Dry slide bearings with a supporting skeleton are preferred for the push-button slide bearings of sintered metals with plastic fillings.

Eine bevorzugte Ausführungsform eines erfindungsgemäßen Meßtasters ist beispielsweise in der Zeichnung dargestellt und zwar zeigt F i g. 1 einen Querschnitt durch einen solchen Tandem-Meßtaster beim Einsatz und F 1 g. 2 die vergrößerte Darstellung des zugehörigen Tasterkopfs. A preferred embodiment of a probe according to the invention is shown for example in the drawing and that FIG. 1 shows a cross section by such a tandem probe during use and F 1 g. 2 the enlarged view of the associated probe head.

Hierbei zeigt F i g. 1 einen Tandem-Meßtaster, bei dem nach dem Planschleifen die Werkstücke 1 durch die Vorschubkräfte 2 der Planschleifmaschine kontinuierlich unter die Tastspitze und der Tastspitzengeometrie gleiten die Werkstücke an der Kegelfläche 4 und an der Kugelfläche 5 entlang. Durch die Feder 6, zwischen Vorhubeinstellschraube 7 am Meßstößel 8 und dem Meßtastergehäuse 9, sowie der Feder 10 werden axiale Kräfte auf den vorderen Taststößel 11 wirksam. Diese axialen Federkräfte bewirken Seitenkräfte 12, welche im Berührungspunkt der Werkstücke mit der Tastspitze, jeweils rechtwinklig zur Tangente auf die Tastspitze wirken. Here, FIG. 1 a tandem probe for which, after surface grinding the workpieces 1 by the feed forces 2 of the surface grinder continuously The workpieces slide under the stylus tip and the stylus tip geometry Conical surface 4 and along the spherical surface 5. By the spring 6, between the pre-stroke adjustment screw 7 on the plunger 8 and the probe housing 9, as well as the spring 10 are axial forces effective on the front push rod 11. These axial spring forces cause side forces 12, which are at right angles at the point of contact of the workpieces with the probe tip act on the probe tip at the tangent.

Die Seitenkräfte 12 an der Tastspitze werdea als Kräftepaar in den Gleitlagern 13 und 14 wirksam aufgenommen. Hierbei entsteht in den Gleitlagern 13 und 14 und an dem Taststößel 11 eine bestimmte erwünschte Dämpfungsreibung durch Flächenpressung.The side forces 12 at the probe tip are used as a pair of forces in the Plain bearings 13 and 14 were effectively added. This creates 13 in the plain bearings and 14 and on the plunger 11 a certain desired damping friction Surface pressure.

Damit die Meßkräfte im unteren Meßbereich nicht zu groß werden, wirkt die Dämpfung progressiv entsprechend der Hubhöhe und Tastspitzengeometrie. Außerdem wird nach Voreinstellen mit der Vorhubeinstellschraube 7 der Meßstößel 8 so weit angehoben, daß der Ferritkern 15 im induktiven Meßspulensystem 16 eine Grundstellung optimal dem gewählten Meßbereich einnimmt. Damit benötigt der Tandem-Meßtaster auch bei Tastlücken nur geringste Eintauchtiefen wobei im normalen Meßbereich, z. B. i 30# nur an der Kugelmantelfläche 3 angefahren wird. So that the measuring forces in the lower measuring range do not become too great, acts the damping progressively according to the stroke height and probe tip geometry. aside from that the plunger 8 becomes so far after presetting with the pre-stroke adjustment screw 7 raised so that the ferrite core 15 in the inductive measuring coil system 16 has a basic position optimally occupies the selected measuring range. So the tandem probe also needs at touch gaps only the slightest immersion depths in the normal measuring range, z. B. i 30 # is only approached at the spherical surface 3.

Im übrigen steht der Taststößel allein unter Federwirkung des Meßstößels und/oder der zwischengeschalteten Vorhubeinstellungsschraube. Otherwise, the feeler plunger is solely under the action of the spring action of the measuring plunger and / or the intermediate pre-stroke adjustment screw.

Desweiteren zeigt F i g. 2 die Tastspitze 3 mit Werkstück 1 in verschiedenen Berührungshöhen. Im Berührungspunkt 17 und im Bereich der Kugelfläche 5 bleiben die Seitenkräfte 18 gering entsprechend auch die Gleitreibungskräfte und die Dämpfungswirkungen, d. h. bei geringer Meßkraft ist der Meßtaster ohne Dämpfung schnell. Im Bereich der Kegelfläche 4 erhöhen sich die Seitenkräfte 19 entsprechend den axialen Federkräften 6 und 10 der Federn nach Fig. 1. Die Dämpfung wirkt somit progressiver entsprechend der Hubhöhe, wobei der Wirkungsbereich der Feder 10 nach F i g. 1 als Überlastbereich wie ein Stoßdämpfer wirkt. Furthermore, FIG. 2 the probe tip 3 with workpiece 1 in different Contact heights. Remain in the contact point 17 and in the area of the spherical surface 5 the side forces 18 low, correspondingly also the sliding friction forces and the damping effects, d. H. if the measuring force is low, the probe is fast without damping. In the area the conical surface 4, the side forces 19 increase in accordance with the axial spring forces 6 and 10 of the springs according to FIG. 1. The damping thus acts more progressively accordingly the lifting height, the range of action of the spring 10 according to FIG. 1 as the overload area acts like a shock absorber.

Noch größere unzulässige Berührungshöhen im Bereich 20 an der Zylinderfläche 21 bewirken mit maximalen Vorschubkräften 2 an der Sollbruchstelle 23 einen gewollten Bruch des austauschbaren Taststößels 11. Somit bleibt auch bei sehr extremen Beanspruchungen das wertvolle induktive Meßsystem ohne Beschädigungsmöglichkeit funktionsfähig. Even greater impermissible contact heights in area 20 on the cylinder surface 21 with maximum feed forces 2 at the predetermined breaking point 23 cause a desired one Breakage of the exchangeable feeler plunger 11. This means that it remains even under very extreme loads the valuable inductive measuring system works without the possibility of damage.

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Claims

Claims: 1. Probe with inductive measuring system for fast Measurement processes in continuously operating grinding machines, with the workpieces can be pushed through by a feed device under the probes and in faster Sequence can be scanned and the measurement signals after an electronic evaluation for Control of the infeed systems of the grinding machines are used, the probe in a front plunger and a rear measuring plunger is divided and behind the Probe tip a predetermined breaking point is provided to secure the inductive measuring system, characterized by the following combination of features: a) that the front plunger (11) is under the action of stepped axial spring forces and b) that it is in two consecutive Plain bearings (13, 14) is guided to absorb the side forces and generate a Damping friction and c) that the rear plunger (8) has a pre-stroke adjustment screw (7) has to reduce the stroke movement in tactile gaps and through the separation can only be actuated axially by the feeler plunger (11) without side forces.

2. Probe according to claim 1, characterized in that the probe plunger (11) under the action of the spring (6) of the measuring plunger (8) with the interposition of the Pre-stroke adjustment screw (7) is at a standstill.

3. Probe according to claim 1 or 2, characterized in that the probe tip (3) of a spherical shape (5) in a cone (4) with an adjoining cylindrical shape (21) passes.

4. Probe according to one of claims 1 to 3, characterized in that that the probe plunger (11) and the probe tip (3) with wear-resistant hard material is equipped

5. Probe according to one of claims 1 to 4, characterized in that that the front plunger (11) without stick-slip effect in dry sliding bearings (13, 14) made of corrosion-resistant metal skeletons with plastic embedding.

The invention relates to a probe with an inductive measuring system for fast measurement processes in continuously operating grinding machines, with the Workpieces can be pushed through by a feed device under the probes and can be scanned in quick succession and the measurement signals after an electronic evaluation are used to control the feed systems of the grinding machines, the probe is divided into a front plunger and a rear measuring plunger and behind the probe tip a predetermined breaking point is provided to secure the inductive Measuring system.

In this case, the workpieces are usually unclamped by a feed device pushed through the machine and the ground workpieces are still in the production flow measured continuously without tension. With electronic measuring signal evaluation devices, z. B. according to DE-OS 29 49 427, it is possible here to use the measurement signals for the thickness measurement so to select that disturbance variables such as abrasive grains, abrasive burrs and workpiece or machine vibrations do not cause malfunctions in the delivery devices.

The use of split probes with a predetermined breaking point is for example known according to AT-PS 3 56 999 for the control of copying machine tools, wherein the non-directional pivoting mounting of the sensor lever for total measurements of <workpiece thickness dimensions cannot be used on grinding machines.

There is also a lack of freedom in the axial direction here, which is the case with grinding machines is important for setting up work on unsanded workpieces with a large allowance.

The probe according to DE-AS 23 56 030 and DE-AS 10 28 792 have just like the DD-PS 1 41 569 without an analog inductive measuring signal all not those Ability to be used for summation circuits on grinding machines.

On the other hand, there is the disadvantage of known measuring heads on grinding machines in the fact that the pneumatic damping of the same a resetting of the deflected Delay the tactile fingers systematically because they are set sluggishly. A slow default is desired with these measuring heads to gaps with the by the attenuators To be able to bypass guided feeler fingers, but this also causes false signals to be faulty reported as workpiece dimensions.

When continuously grinding and measuring unclamped workpieces Therefore, the inductive one-touch probes with linear ball bearings known from measurement technology are also used for the plunger, used for quick measurements without damping. Because of the strong Stress when measuring in the machine, there are reinforced versions with otherwise same design as the fine probe. But also when using this reinforced Machine button, the failure rate is still relatively high. This leads to a lot of failures the probe tip and the measuring ram with the ball guide due to excessive lateral forces, which, however, occur regularly in the grinding process with unclamped workpieces.

Attempts have already been made with additional flushing devices and with Workpiece hold-downs to master the difficult flowing measurement. Here but are disadvantageous are the permanent back pressure of the hold-down device, which z. B. worsen the parallelism of the workpieces in face side grinding.

It is now the main object of the invention to address the known deficiencies correcting the machine button against lateral forces and by corresponding friction to dampen the measuring system optimally in order to achieve good dynamic capabilities for fast measurements on grinding machines.