DE10309242A1 - Spindle for lathe or machining device, comprising sensor element for surveillance of gas pressure level - Google Patents

Abstract

The tool insertion area (1) of the spindle is assembled of an inner (2) and an outer conical element (3), a pulling rod (5) with a conical front area (9), and several clamping elements (8). When the rod (5) is axially moved the clamping elements (8) are moved against the inner surface of the outer cone (3), which is pulled tightly into the inner cone (2). Pressurized gas is guided into the gap (10) between the pulling rod (5) and the tool insertion area (1). When both conical elements (2, 3) are joined the pressure in the ducts is reduced. A sensor (11), located at the gap (10) indicates if the tool is safely joined.

Description

The invention relates to a motor spindle for tool processing, especially for a milling or turning machine, according to the preamble of claim 1.

Motor spindles are generally known, for example from the DE 19 951 405 C2 , They are used for tool processing, especially for milling and turning machines. At the end of the motor spindles there is a tool holder which has an outwardly opening recess into which a corresponding projection of a tool holder can be inserted in a form-fitting manner. The tool holder is preferably provided with an inner cone and the tool carrier with an outer cone. The outer cone is pulled into the inner cone with great force to releasably connect the tool holder to the tool carrier. This is done by means of a longitudinally displaceable pull rod, which runs coaxially in the motor spindle and extends into the inner cone. There it interacts with pliers-like clamping elements, which are pressed radially outwards when the pull rod is pulled back, positively engaging behind an undercut of the tool holder. In order to keep the inner cone free of impurities and in particular to protect it from fine metal chips, a gas from a reservoir is used which, for example, flows under pressure along the drawbar over the inner cone to the outside. In this way, the inner cone and the outer cone are kept free of dirt particles and the like when loosening and establishing the cone connection. The gas outlet is closed when the outer cone is drawn into the inner cone.

To capture the state of the connection Sensors used the location of the tie rod in the motor spindle to capture. For this purpose, the pull rod has one at its rear end Contour that is queried by the sensor of the proximity switch becomes. The movement of the pull rod is only a few millimeters, so that length changes by warming the spindle can affect the accuracy of the query. It can happen that a tool change is initiated even though the tool is still unsolved is what causes significant damage to lead can.

The object of the invention is the condition of the connection between the tool holder and the tool holder capture.

The solution to this problem is through given the features specified in claim 1. By the characteristic Characteristics of the subclaims the motor spindle advantageously further developed.

The solution provides that the means of registration determine the state of the connection based on the gas pressure.

A very secure connection results itself when the tensioning elements are retracted from the pull rod this radially outwards be pressed whereby they engage behind an undercut of the tool carrier in a form-fitting manner.

With a simple solution the state of the connection is determined based on a pressure drop in the gas.

The detection means are expedient provided with a pressure sensor.

The invention is described below closer to a drawing described. Show it:

1 a section of a motor spindle with a tool holder and a tool holder, the cone are loosely inserted into each other, and

2 the motor spindle according to 1 with firmly retracted outer cone of the tool holder.

1 shows a section of a motor spindle, not shown, which has a tool holder on one of its end faces 1 having. This is with an inner cone 2 provided, in which a corresponding outer cone 3 a tool holder 4 is plugged in. The tool carrier 4 can, for example, be provided with an external thread onto which a tool can be screwed.

Next shows 1 a longitudinally displaceable pull rod 5 that runs coaxially through the motor spindle and extends over the inner cone 2 extends outwards. For this purpose, the outer cone has a corresponding recess 6 provided, which in particular has an undercut.

Around the outer cone 3 firmly in the inner cone 2 to be pulled are pliers-like clamping elements 8th provided that when moving the pull rod - in 1 to the right - pushed radially outwards. For this is on the drawbar 5 a conical element 9 provided that related to the 1 left end of the clamping elements 8th interacts.

2 shows that of the element 9 pliers-shaped clamping elements pressed radially outwards 8th doing the undercut 7 of the tool holder 4 reach behind positively. At the same time, the power-operated pull rod pulls 5 the outer cone 3 - Applying a preload to this - in the inner cone 2 , The connection is released in the reverse order.

To prevent dirt particles and metal chips from collecting in the inner cone and thus a firm connection of the two cones 2 . 3 prevent the annular gap area 10 between the tie rod 5 and the tool holder 1 pressurized with air from the inner cone 2 towards the outer cone 3 flows outwards.

The outlet opening of the compressed air is when the outer cone is firmly drawn into the inner cone 3 sealed gastight.

So compressed air always flows outwards when the two cones 2 . 3 are not firmly inserted into each other. In this case, the pressure of the compressed air in the lines is significantly lower than when the inner cone outlet is closed. To record the gas pressure is in the range 10 a pressure sensor 11 arranged, which is connected to detection means. The motor spindle can be locked via the pressure detection. A corresponding control can be provided for this.

1

tool holder

2

inner cone

3

skittles

4

tool carrier

5

pull bar

6

recess

7

undercut

8th

clamping element

9

conical element

10

Area

11

pressure sensor

Claims (4)

Motor spindle for tool processing, especially for a milling or turning machine, with an end tool holder ( 1 ), which has an inner cone that opens outwards ( 2 ) in which a corresponding outer cone ( 3 ) a tool holder ( 4 ) can be inserted with a pressurized gas which is released from the inner cone when the cone connection is released and 2 ) the tool holder ( 1 ) in the direction of the tool holder ( 4 ) flows outwards, with connecting means for establishing a detachable connection between the tool holder ( 1 ) and the tool carrier ( 4 ), comprising a pull rod that is longitudinally displaceable inside the motor spindle ( 5 ) and in the area ( 10 ) the cone arranged with the pull rod ( 5 ) interacting clamping elements ( 8th ), with the help of which the outer cone ( 3 ) when pulling back the drawbar ( 5 ) in the inner cone ( 2 ) is pulled and sealed gas-tight, and with detection means for detecting the state of the connection, characterized in that the detection means detect the state of the connection on the basis of the gas pressure. Motor spindle according to claim 1, characterized in that the pincer-shaped clamping elements ( 8th ) when pulling back the drawbar ( 5 ) are pushed radially outwards, creating an undercut ( 7 ) of the tool holder ( 4 ) reach behind positively. Motor spindle according to claim 1 or 2, characterized in that the detection means based on a pressure drop in the gas Record the state of the connection. Motor spindle according to one of claims 1 to 3, characterized in that the detection means comprises a pressure sensor ( 11 ) exhibit.