Method for the ultrasonic measurement of a wall thickness in hollow valves

Abstract

A method for measuring a wall thickness in hollow valves may include determining a wall thickness in a region of a valve stem using at least one ultrasonic sensor, wherein the one ultrasonic sensor may be oriented with respect to a surface on the valve stem in such a manner that an emitted ultrasound may be introduced into the surface in a perpendicular manner. The method may additionally or alternatively include determining a wall thickness in a region of a chamfer using the at least one ultrasonic sensor, wherein the at least one ultrasonic sensor may be positioned at a location on the chamfer at which an inner tangent in a cavity runs parallel to an outer tangent on the chamfer, and wherein the ultrasonic sensor is oriented with respect to the tangents in such a manner that an emitted ultrasound is introduced into the surface in a perpendicular manner.

Claims

1. A method for measuring a wall thickness in hollow valves with and without a hollow valve head, comprising at least one of: determining a wall thickness in a region of a valve stem simultaneously using two or four ultrasonic sensors, wherein the ultrasonic sensors are oriented with respect to a surface on the valve stem in such a manner that an emitted ultrasound is introduced into the surface in a perpendicular manner; and determining a wall thickness in a region of a chamfer using at least one of the ultrasonic sensors, wherein the at least one of the ultrasonic sensors is positioned at a location on the chamfer at which an inner tangent in a cavity runs parallel to an outer tangent on the chamfer, and wherein the at least one of the ultrasonic sensors is oriented at an acute angle relative to a plate plane surface of a valve base, and oriented with respect to the tangents in such a manner that an emitted ultrasound is introduced into a surface of the chamfer in a perpendicular manner.

2. The method according to claim 1, wherein the acute angle is in a range between 20 and 40.

3. The method according to claim 1, wherein the measuring takes place in a fluid.

4. The method according to claim 1, wherein the hollow valve to be measured is turned during the measuring.

5. The method according to claim 1, wherein at least one of the ultrasonic sensors is a high frequency ultrasonic sensor.

6. The method according to claim 1, wherein the wall thickness is measured in at least four circumferential locations of the hollow valve.

7. The method according to claim 1, wherein the wall thickness is measured on a blank or on a finished hollow valve, with a closed cavity.

8. The method according to claim 7, further comprising determining a wall thickness in a region of a valve base by at least one of the ultrasonic sensors, wherein the at least one of the ultrasonic sensors is oriented with respect to the plate plane surface of the valve base in such a manner that an emitted ultrasound is introduced into the plate plane surface in a perpendicular manner.

9. The method according to claim 1, wherein a relative movement takes place between the hollow valve to be measured and the ultrasonic sensors in a direction of an axis of the valve stem during the measuring.

10. A method for the production of a hollow valve with a hollow valve head, comprising: introducing a cavity into the hollow valve by at least one of boring and electrochemical machining (ECM); and measuring a wall thickness of the hollow valve on at least one of a valve stem, a chamfer, and a valve base by at least one of: determining the wall thickness in a region of the valve stem using two or four ultrasonic sensors, wherein the ultrasonic sensors are oriented with respect to a surface on the valve stem in such a manner that an emitted ultrasound is introduced into the surface in a perpendicular manner; determining the wall thickness in a region of the chamfer using at least one of the ultrasonic sensors, wherein the at least one of the ultrasonic sensors is positioned at a location on the chamfer at which an inner tangent in a cavity runs parallel to an outer tangent on the chamfer, and wherein the at least one of the ultrasonic sensors is oriented at an acute angle relative to a plate plane surface of the valve base, and is oriented with respect to the tangents in such a manner that an emitted ultrasound is introduced into a surface on the chamfer in a perpendicular manner; and determining the wall thickness in a region of the valve base at least one of the ultrasonic sensors, wherein the at least one of the ultrasonic sensors is oriented with respect to the plate plane surface of the valve base in such a manner that an emitted ultrasound is introduced into the plate plane surface in a perpendicular manner.

11. A hollow valve with or without a hollow valve head which was produced by; introducing a cavity into the hollow valve by at least one of boring and electrochemical machining (ECM); and measuring a wall thickness of the hollow valve on at least one of a valve stem, a chamfer, and a valve base by at least one of: determining the wall thickness in a region of the valve stem using two or four ultrasonic sensors, wherein the ultrasonic sensors are oriented with respect to a surface on the valve stem in such a manner that an emitted ultrasound is introduced into the surface in a perpendicular manner; determining the wall thickness in a region of the chamfer using at least one of the ultrasonic sensors, wherein the at least one ultrasonic sensors is positioned at a location on the chamfer at which an inner tangent in a cavity runs parallel to an outer tangent on the chamfer, and wherein the at least one of the ultrasonic sensors is oriented at an acute angle relative to a plate plane surface of the valve base, and is oriented with respect to the tangents in such a manner that an emitted ultrasound is introduced into a surface of the chamfer in a perpendicular manner; and determining the wall thickness in a region of the valve base using at least one of the ultrasonic sensors, wherein the at least one of the ultrasonic sensors is oriented with respect to the plate plane surface on the valve base in such a manner that an emitted ultrasound is introduced into the plate plane surface in a perpendicular manner.

12. The method according to claim 2, wherein the measuring takes place in a fluid.

13. The method according to claim 3, wherein the fluid is one of oil or water provided with a corrosion protection.

14. The method according to claim 2, wherein the hollow valve to be measured is turned during the measuring.

15. The method according to claim 2, wherein at least one of the ultrasonic sensors is a high frequency ultrasonic sensor is used.

16. The method according to claim 2, wherein the wall thickness is measured in at least four circumferential locations of the hollow valve.

17. The method according to claim 3, wherein the hollow valve to be measured is turned during the measuring.

18. The method according to claim 3, wherein at least one of the ultrasonic sensors is a high frequency ultrasonic sensor.

19. The method according to claim 3, wherein the wall thickness is measured in at least four circumferential locations of the hollow valve.

20. The method according to claim 3, wherein at least a portion of the hollow valve being measured is submerged in the fluid such that the measuring takes place in the fluid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred example embodiments of the invention are illustrated in the drawings and are explained in further detail in the following description, wherein the same reference numbers refer to identical or similar or functionally identical components.

(2) There are shown, respectively diagrammatically

(3) FIG. 1 a sectional illustration through a hollow valve during measurement of a wall thickness in the region of a valve stem,

(4) FIG. 2 a sectional illustration through a hollow valve in a cavity produced by means of electrochemical machining during the determining of wall thickness in the region of the cavity,

(5) FIG. 3 a device for carrying out the method according to the invention,

(6) FIG. 4 two diagrams for visualization of the wall thickness deviation,

(7) FIG. 5 the device according to the invention of FIG. 3 with a total of four ultrasonic sensors.

DETAILED DESCRIPTION

(8) According to FIG. 1, a wall thickness b.sub.s of a hollow valve 1 is determined in the region of a valve stem 2 by means of at least one ultrasonic sensor 3, wherein the ultrasonic sensor 3 is oriented with respect to the surface on the valve stem 2 in such a manner that the emitted ultrasound is introduced into the surface in a perpendicular manner, here therefore perpendicularly to the axis of the hollow valve 1. The ultrasonic sensor 3 is configured here not only for emission, but also for reception of a reflected ultrasonic signal, which can then be evaluated by means of an evaluation unit 4. As can be seen from the illustration of FIG. 1, the hollow valve 1 has a drilled cavity 5, which extends not only over the valve stem 2 but into the region of the valve head 6.

(9) In contrast thereto, the hollow valve 1 illustrated according to FIG. 2 has in the region of its valve head 6 a cavity 5 produced by means of electrochemical machining (ECM), wherein the wall thickness b.sub.1 or b.sub.2 of a cavity 5 produced in such a manner, owing to the production process of the cavity 5 is distinctly more difficult to determine. The wall thickness b.sub.1 lies here in the region of a valve base 7, which is defined by a plate plane surface 8. The wall thickness b.sub.2, on the other hand, lies in the region of a chamfer 9. To determine the wall thickness b.sub.2, the ultrasonic sensor 3 is now positioned at a location on the chamfer 9 at which an inner tangent 10 in the cavity 5 runs parallel to an outer tangent 11 on the chamfer 9 and wherein the ultrasonic sensor 3 is oriented with respect to these tangents 10, 11 in such a manner that the emitted ultrasound is introduced into the surface in a perpendicular manner and at the same time perpendicularly to the two tangents 10, 11 into the valve head 6 of the hollow valve 1. The perpendicular introducing of the ultrasound enables an exact determining of the wall thickness.

(10) Observing FIG. 2 further, it can be seen that the ultrasonic sensor 3 is arranged in a range of 20<<40 relative to the plate plane surface 8, in this angle range normally the location lies at which the two tangents 10, 11 run parallel to one another.

(11) According to FIG. 3 a device 12 for carrying out the measurement method is shown, wherein the device 12 has an arm 13 holding the valve which is to be measured. This arm 13 is not only able here to turn the hollow valve 1, which is to be measured, about a valve axis 14, so that several measurement points or respectively several wall thicknesses b.sub.s, b.sub.2 can be determined in the region of the valve stem 2 or respectively of the chamfer 9, but it is in addition also able to submerge the hollow valve 1, which is to be measured, into a fluid 15, for example into oil or in water provided with a corrosion protection, so that the actual measuring of the wall thickness b takes place in the fluid 15. This is able to be accomplished in a considerably simpler, more cost-efficient and also better automatable manner than a measuring by means of contact gel, which firstly has to be applied and removed again after the measuring.

(12) In order to be able to fulfil as high a quality standard as possible, the testing of the wall thickness b.sub.1 or respectively b.sub.2 or the wall thickness b.sub.s of the valve stem 2 should take place at several points, wherein there are basically two different method variants. According to the device 12 illustrated in FIG. 3, the hollow valve 1 which is to be measured is turned about its valve axis 14 during or respectively between two measurings. Alternatively hereto, it is also conceivable that two or, as is shown in FIG. 5, four ultrasonic sensors 3 are directed simultaneously onto the hollow valve 1 which is to be measured, whereby in particular also the cycle time for carrying out the wall thickness measurement can be reduced.

(13) In FIG. 4 two diagrams are illustrated, which show a wall thickness deviation in the valve stem 2 in a reject part (upper illustration) and in a good part (lower illustration). It can be clearly seen here that the wall thickness deviation in the good part, illustrated below, runs closely around the zero line, whereas in the upper illustration in the reject part it is distributed comparatively widely. Such reject parts are therefore preferably already to be rejected in an early manufacturing step of the hollow valve 1, in particular directly after the production of the cavity 5, 5, and especially before further expensive and work-intensive manufacturing steps, such as for example a grinding or coating.

(14) With the method according to the invention and with the device 12 according to the invention it is therefore possible to carry out a 100% testing of the produced hollow valves 1, whereby a high quality can be guaranteed.