DE102006012516A1 - Tight chamfer processing tool for use in automobile industry, has cutting head axially movable relative to housing against spring force of elastic unit that absorbs force developed during processing of tight chamfer in axial direction - Google Patents

Abstract

The tool (1) has a conical cutting head (3) arranged at a housing (4) and rotatable around a rotating axis. The cutting head is axially movable relative to the housing against a spring force of an elastic unit (5) e.g. spiral spring. The cutting head is supported at the housing in an axially slidingly movable manner. A stop (6) is provided for limiting a moving path (X) of the cutting head against the housing. The elastic unit absorbs the force developed during the processing of the tight chamfer in an axial direction.

Description

The The invention relates to a tool for machining a sealing chamfer with the features of the preamble of claim 1.

she comes from the European Patent 1,190,798 B1. In this is a tool head for use described in machine tools. The tool head essentially consists from a basic body, an axial over protruding from the main body Tool shank, with a sliding member which can be displaced relative to the main body, for adjusting at least one cutter carrier and one with the thrust member detachable electric motor assembly and a power supply device for the Motor assembly. This tool is suitable for editing of valve stem guides and at the same time for processing the valve seat rings of gas exchange valves in a cylinder head of an internal combustion engine. For editing the valve stem guides is a hone and hell for the processing of the valve seat rings is a replaceable cutting head with a angle-adjustable cutting plate provided.

by virtue of the ever sharper future exhaust gas legislation and the commitment of the automotive industry, To reduce fuel consumption is a particularly good closing behavior the inlet and outlet gas exchange valves necessary. To the greatest possible tightness the gas exchange valves of an internal combustion engine with respect to To ensure valve seat ring Form tolerances are to be kept to the micrometer range. such Mold tolerances can with a generic tool in a mass production very difficult to comply.

task The present invention is a tool for machining a sealing chamfer of a valve seat ring show, with the also Form tolerances in the micrometer range can be maintained.

These The object is achieved by the features in the characterizing part of the claim 1 solved.

by virtue of the embodiment of the invention are the forces occurring during the processing of the Dichtfase by an elastic element, for example a spiral spring in the axial direction caught, d. H. that the tool centers itself during machining. This will be an existing form error, the previous one Processing of the valve seat ring may have arisen, equalized and there can be mold tolerances up to the micrometer range.

Around to ensure the relative movement of the cutting head relative to the housing is the cutting head according to claim 2 sliding on the housing stored.

In order to a defined interaction of cutting head, spring force of the elastic Element and housing is adjustable, is in accordance with claim 3 a stop provided.

Around in a simple way, the bias in the processing of Sealing bevel which vary, the stopper according to claim 4 in its axial Location changeable.

The the simplest arrangement of the elastic element, such as a Spiral spring is according to claim 5 between the cutting head and the housing.

The Embodiment according to claim 6 allows a very simple and compact design of the tool according to the invention.

With The embodiment according to claim 7 is a trouble-free clamping and driving the tool according to the invention with a prime mover, such. B. an electric motor possible.

in the The invention is based on a preferred embodiment closer in two figures explained.

1 shows the top view of a tool according to the invention;

2 shows a section through a tool according to the invention.

1 in which the same reference numbers apply to the same components as in 2 shows the top view of a tool according to the invention 1 , The tool 1 is largely rotationally symmetric to a rotation axis 1' built up. The tool 1 consists essentially of a mandrel 8th , which rotates with a housing 4 is connected, wherein the mandrel 8th , as in 2 recognizable, axially in the housing 4 is screwed. To the case 4 is diametrically opposite the mandrel 8th a conical cutting head 3 sliding on the housing 4 arranged. Radial to the conical cutting head 3 is a valve seat ring 2 shown. The housing 4 also has a stop 6 on, under 2 is explained in more detail.

In 2 is a section along a plane AA, corresponding to the axis of rotation 1' , through the tool 1 shown. How to 1 already executed, the tool exists 1 essentially from the axially into the housing 4 screwed clamping mandrel 8th , The mandrel 8th and the case 4 each have an axial bore in which a mandrel 7 is movably arranged. The thorn 7 also points to the mandrel 8th opposite side on an axial threaded bore and a conical end. At the conical end is the cutting head 3 can be arranged and with a fastener, in the present embodiment, a screw on the mandrel 7 fixable. Coaxial to the cutting head 3 is in turn the valve seat ring to be machined 2 also shown cut. The cutting head 3 lies on a sealing chamfer 2 ' of the valve seat ring 2 on. The cutting head 3 is of an elastic element 5 , In the present embodiment, a coil spring which is coaxial with the mandrel 7 extends, against the housing 4 supported, wherein a housing wall of the housing 4 again coaxially around the elastic element 5 extends. To an axial movement of the cutting head 3 to allow this slide is movable in the housing 4 , or the housing wall, stored.

Will the caulking 2 ' a valve seat ring 2 edited, so will the tool 1 over the mandrel 8th rotationally driven by an unillustrated prime mover, such as an electric motor, and axially into the valve seat ring 2 on the side of the caulk 2 ' inserted. Due to the elastic element 5 will be at the first touch of the cutting head 3 with the caulking 2 ' gently applied pressure. This gentle pressure turns the cutting head 3 very precise on the caulk 2 ' centered. Upon further application of pressure against the caulk 2 ' becomes the cutting head 3 against the spring force of the elastic element 5 further into the hous se 4 pressed. Thus, the machining pressure is slowly increased by the inventive design. To create a defined, maximum biasing pressure is in the mandrel 7 perpendicular to the axis of rotation 1' a cross thorn 7 ' brought in. This cross thorn 7 ' is in a slot 10 in the mandrel 8th guided. The Querdorn 7 ' and the slot 10 form a common stop 6 , Thus, the stop defines 6 a maximum displacement of the cutting head 3 with respect to the housing 4 ,

In a further embodiment, the cutting head 3 also radially on the outside of the housing 4 be stored move. Furthermore, it is possible to use the elastic element 5 also radially outside of the housing 4 to arrange. As an elastic element 5 In addition to coil springs, other elastic components such. As elastomers or foams or air springs are used. Also hydraulic systems are possible.

Furthermore, it is possible the stop 6 In its axial position changeable, ie to make adjustable, which in a simple way, the maximum bias of the cutting head 3 can be adjusted.

Due to the inventive design of the tool 1 is the observance of extremely precise roundness tolerances (shape tolerances) with deviations in the micrometer range, up to a minimum of 10 μm, the sealing chamfer 2 ' of the valve seat ring 2 possible and this despite the extremely high material hardness of valve seat rings 2 , in particular the exhaust valve seat rings, which have a hardness of 350 to 450 HB (Brinell hardness). Thus, a process-safe production in a machining center is possible. The pre-processing of the sealing chamfer 2 ' is carried out as known by stinging, but the finishing is preferably done with a tool according to the invention 1 with a diamond-coated cutting head 3 , Due to the displaceability of the cutting head 3 with respect to the housing 4 a leveling error that may have occurred due to the pre-processing is equalized.

• 1. Reduzierung der Bearbeitungszeit bei der Bearbeitung der Dichtfase eines Ventilsitzringes 2 (explizit bei der Vorbearbeitung);
• 2. Die Nacharbeit und der Ausschuss werden reduziert;
• 3. Es ergibt sich eine größere Dichtheit der Gaswechselventile beim Betrieb der Brennkraftmaschine und somit eine Reduzierung des Schadstoffausstoßes;
• 4. Es resultiert eine größere Unabhängigkeit bei der Auswahl von schwer zerspanbaren Werkstoffen im Ventilsitzring.

Thus, the following advantages result due to the inventive design:

• 1. Reduction of machining time when machining the sealing nose of a valve seat ring 2 (explicitly during preprocessing);
• 2. The rework and the committee are reduced;
• 3. It results in a greater tightness of the gas exchange valves during operation of the internal combustion engine and thus a reduction of pollutant emissions;
• 4. It results in a greater independence in the selection of difficult-to-machine materials in the valve seat ring.

1

Tool

1'

axis of rotation

2

Valve seat ring

2 '

sealing chamfer

3

cutting head

4

casing

5

elastic element

6

attack

7

mandrel

7 '

cross thorn

8th

mandrel

9

screw

10

Long hole

Claims (7)

Tool ( 1 ) for processing a sealing chamfer ( 2 ' ), in particular a valve seat ring ( 2 ) of a gas exchange valve of an internal combustion engine, with a conical cutting head ( 3 ), which is attached to a housing ( 4 ) and about an axis of rotation ( 1' ) is rotatable, wherein the cutting head ( 3 ) and the housing ( 4 ) Are axially displaceable, characterized in that the cutting head ( 3 ) against a spring force of an elastic element ( 5 ) axially relative to the housing ( 4 ) is displaceable. Tool according to claim 1, characterized in that the cutting head ( 3 ) on the housing ( 4 ) Is mounted axially movable sliding. Tool according to claim 1 or 2, characterized in that a stop ( 6 ) is provided for limiting a displacement path (X) of the cutting head ( 3 ) opposite the housing ( 4 ). Tool according to claim 3, characterized in that the stop ( 6 ) Is changeable in its axial position. Tool according to one of the claims 1 to 4, characterized in that the elastic element ( 5 ) on the one hand against the cutting head ( 3 ) and on the other hand against the housing ( 4 ) is supported. Tool according to one of the claims 3 to 5, characterized in that the cutting head ( 3 ) detachable on a in the housing ( 4 ) sliding movably arranged mandrel ( 7 ), whereby the stop ( 6 ) of the thorn ( 7 ) and the housing ( 4 ) is formed. Tool according to one of the claims 1 to 6, characterized in that the tool ( 1 ) coaxial with the axis of rotation ( 1' ), diametrically to the cutting head ( 3 ) a mandrel ( 8th ) having.