Device and method for arranging at least one test specimen

Abstract

Device (1) for arranging at least one test specimen (2) on a cylinder bore coating (3) of a cylinder crankcase (4) of an internal combustion engine, characterized by a housing (6) which can be inserted into a cylinder bore (5) of the internal combustion engine in which the at least one test specimen (2) is to be arranged, wherein a retaining plate (7) is arranged on a top side of the housing (6), which, after the housing (6) has been inserted into the cylinder bore (5), can be placed on a top side of the cylinder crankcase (4) and fastened to it, wherein at least one test specimen holder (9) is movable radially out of the housing (6) in the direction of the cylinder bore coating (3) for pressing the at least one test specimen (2) onto the cylinder bore coating (3).

Description

[0001] The invention relates to a device for arranging at least one test body according to the features of the preamble of claim 1 and to a method for arranging at least one test body according to the features of the preamble of claim 5.

[0002] A method for determining the tensile strength of a coating is known from the prior art, as described in DE 10 2009 032 817 A1. Two hollow cylindrical test specimens are arranged such that corresponding base surfaces of the test specimens are in contact with each other. The test specimens are fixed in this position by a holding element. An inner surface of the test specimens is coated in the joint area of ​​the test specimens. The holding element is released, and a tensile force is applied in the direction of the symmetry axis of the test specimens until the coating fails.

[0003] German patent application DE 10 2010 043 399 A1 discloses a method for testing the adhesion and layer strength of a surface layer applied to a first side of a substrate, comprising the following steps: - Creating a recess in the substrate, wherein the recess extends into the substrate from a second side of the substrate facing away from the first side and is limited in its depth by a base surface, - Inserting a pressure body into the recess until one end of the pressure body rests against the base surface, - Pressing the pressure body against the base surface such that the pressure body is displaced. The surface layer is a metal-containing surface layer. The pressure body is inserted into the recess from the second side.

[0004] German patent application DE 10 2011 117 686 A1 discloses a method for testing a coating applied to a component. According to the invention, the component is placed in a hot gas test stand and, in a predetermined cycle, is alternately heated by a hot gas stream and cooled by a cold gas stream. During and / or after the cycle, a temperature determination and / or shape measurement in the area of ​​the coating and / or a visual assessment of the coating are performed. Furthermore, the invention relates to a device for carrying out the method.

[0005] The invention is based on the object of providing an improved device and an improved method for arranging at least one test specimen.

[0006] The object is achieved according to the invention by a device for arranging at least one test body having the features of claim 1 and a method for arranging at least one test body having the features of claim 5.

[0007] Advantageous embodiments of the invention are the subject of the subclaims.

[0008] A device according to the invention for arranging at least one test specimen on a cylinder bore coating of a cylinder crankcase of an internal combustion engine comprises a housing which can be inserted into a cylinder bore of the internal combustion engine in which the at least one test specimen is to be arranged, wherein a holding plate is arranged on an upper side of the housing which, after insertion of the housing into the cylinder bore, can be placed on an upper side of the cylinder crankcase and fastened thereto. At least one test specimen holder can be moved radially out of the housing in the direction of the cylinder bore coating for pressing the at least one test specimen onto the cylinder bore coating. In order to be able to insert the housing into the cylinder bore, it must have a smaller cross-section than the cylinder bore of the internal combustion engine.

[0009] The device can also be designed such that a plurality of test specimens can be arranged on the cylinder bore coating at the same time. In this case, the device has a separate test specimen holder for each test specimen to be arranged. With such a device with a plurality of test specimen holders, a smaller number of test specimens can then be arranged on the cylinder bore coating at the same time than there are test specimen holders on the device, i.e. it is not necessary to equip every test specimen holder available on the device with a test specimen. Therefore, the device expediently has such a high number of test specimen holders that the maximum required number of test specimens can be arranged on a cylinder bore coating by means of the device.In this way, the device is suitable for arranging different numbers of test specimens in differently designed cylinder crankcases.

[0010] The device is an adhesive device for position-oriented positioning of the test specimen and for introducing an adjustable adhesive force, preferably by means of at least one central push rod that can be easily operated from outside the cylinder bore. This enables a simple test of the cylinder bore coating, i.e. of its layer adhesion, for example in accordance with DIN 91063, by simply and reproducibly applying the test specimen to the cylinder bore coating. To test the cylinder bore coating, a tensile force must be exerted on the test specimen attached to the cylinder bore coating until the layer fails and the test specimen, along with parts of the cylinder bore coating, tears away from the cylinder crankcase. The layer adhesion of the cylinder bore coating can then be determined from the force applied.To perform this test, DIN 91063 requires precise bonding of test specimens to the cylinder bore coating, which is achievable with the fixture. This eliminates the need to manually attach the test specimen or apply the adhesive force.

[0011] It is also particularly advantageous to attach a sealing ring, such as a so-called V-ring, to the test specimen before bonding in such a way that it surrounds the edge of the contact surface of the test specimen that is to be attached to the cylinder bore coating. This prevents lateral displacement of the adhesive, making it impossible to remove it manually using a hollow milling cutter. This had to be done using state-of-the-art methods when applying the test specimen to avoid distorting the test specimen's bonding surface. Adhesive strength has a significant impact on the tensile strength and the scatter of measurement results.

[0012] The cylinder block, along with the fixture, can be easily placed in a curing oven to cure the adhesive. The fixture is then removed from the cylinder block, and the cylinder bore coating can be tested using the test specimen attached to it. The fixture thus stabilizes measurement results, increases measurement accuracy, and reduces measurement effort.

[0013] Embodiments of the invention are explained in more detail below with reference to drawings.

[0014] Showing: Fig. 1 schematically shows a device arranged in a cylinder crankcase for arranging at least one test specimen in plan view, Fig. 2 schematically shows a perspective view of a device for arranging at least one test specimen, Fig. 3 schematically shows a side view of a device for arranging at least one test specimen, Fig. 4 schematically shows a sectional view of a device for arranging at least one test specimen along the section line IV-IV in Fig. 1, Fig. 5 schematically shows a sectional view of a device for arranging at least one test specimen along the section line VV in Fig. 1, Fig. 6 schematically shows a sectional view of a device arranged in a cylinder crankcase for arranging at least one test specimen along the section line VI-VI in Fig. 1 and Fig. 7 schematically shows a sectional view of a device arranged in a cylinder crankcase for arranging at least one test specimen along the section line VII-VII in Fig. 1.

[0015] Corresponding parts are provided with the same reference numerals in all figures.

[0016] The Fig. 1 to 7 show various views of a device 1 for arranging at least one test specimen 2, also referred to as a stamp, on a cylinder bore coating 3 of a cylinder crankcase 4 of an internal combustion engine, by means of which a corresponding method for arranging the at least one test specimen 2 on the cylinder bore coating 3 of the cylinder crankcase 4 of the internal combustion engine can be carried out. The device 1 is shown in the Fig. 1, Fig. 6 and Fig. 7 is arranged in the cylinder crankcase 4, ie in a cylinder bore 5 of the cylinder crankcase. Fig. 4 to 7 show sectional views of the device 1 along the section line marked with the respective figure number in Fig. 1.

[0017] The device 1 enables a simple test to be carried out on the cylinder bore coating 3, i.e. on its layer adhesion, for example in accordance with DIN 91063, by simply and reproducibly applying the test specimen 2 to the cylinder bore coating 3. To test the cylinder bore coating 3, a tensile force must be exerted on the test specimen 2 attached to the cylinder bore coating 3 until the layer fails and the test specimen 2 tears off from the cylinder crankcase 4 with parts of the cylinder bore coating 3. The layer adhesion of the cylinder bore coating 3 can then be determined from the force applied. In order to carry out this test, DIN 91063 requires precise bonding of test specimens 2 to the cylinder bore coating 3, which can be achieved using the device 1, as explained in more detail below.This means that it is not necessary to attach test specimen 2 by hand and it is also not necessary to apply an adhesive force by hand.

[0018] The device 1 comprises a housing 6, which has a smaller cross-section, ie in particular a smaller diameter, than the cylinder bore 5 of the internal combustion engine in which the test specimen 2 is to be arranged, so that the housing 6 of the device 1, as shown in the Fig. 1, Fig. 6 and Fig. 7, is to be inserted into the cylinder bore 5. A holding plate 7 is arranged on an upper side of the housing 6, which, after the housing 6 has been inserted into the cylinder bore 5, is to be placed on an upper side of the cylinder crankcase 4 and fastened to the cylinder crankcase 4.

[0019] For fastening, fixing screws 8 are passed through holes in the retaining plate 7 and secured in screw holes in the cylinder crankcase 4. These screw holes are used to fasten a cylinder head of the internal combustion engine during assembly of the internal combustion engine, i.e., these screw holes are already present in the cylinder crankcase 4, so that no additional fastening means are required on the cylinder crankcase 4.

[0020] The embodiment of the device 1 shown here has three test specimen holders 9, in each of which a test specimen 2 is to be fixed to the cylinder bore coating 3. Of course, only one or two test specimens 2 can be fixed to the cylinder bore coating 3 using the device 1 if this is sufficient. Thus, in the example shown here, as for example in Fig. 4, only in two of the test specimen holders 9 test specimen 2 is arranged.

[0021] To press the test specimen 2 onto the cylinder bore coating 3, the test specimen holders 9 are movable radially out of the housing 6 in the direction of the cylinder bore coating 3. For this purpose, the test specimen holders 9 in this exemplary embodiment are coupled to two push rods 10 arranged in the housing 6 in the longitudinal direction of the housing in such a way that the test specimen holders 9 can be moved radially by moving the push rods 10 in the longitudinal direction of the housing, ie, parallel to a cylinder bore axis.

[0022] To make this possible, the two push rods 10 are each connected to the test specimen holders 9 via rocker arms 11, via which the movement of the push rods 10 in the longitudinal direction of the housing is to be transmitted to the test specimen holders 9 and converted into a movement radial to the housing 6. For this purpose, the rocker arms 11 are each connected to the respective test specimen holder 9 via a first pivot axis 11.1 and to the respective push rod 10 via a second pivot axis 11.2, as shown in Fig. 4 and Fig. 5. By moving the respective push rod 10 in the longitudinal direction of the housing, a height of the second pivot axis 11.2 increasingly approaches a height of the first pivot axis 11.1 of the respective rocker arm 11, since the rocker arm 11 pivots or tilts about the first pivot axis 11.1. Due to the distance between the two pivot axes 11.1, 11.2 predetermined by the rocker arm 11, the first pivot axis 11.1 and the test specimen holder 9 arranged thereon are radially displaced in the direction of the cylinder bore coating 3, so that the test specimen 2 arranged in the test specimen holder 9 can be pressed against the cylinder bore coating 3.

[0023] In order to enable a uniform movement of the push rods 10 and easy operation of the device 1, the push rods 10 are connected to one another at their upper ends by means of a handle 12, so that by grasping this handle 12 by hand or by means of a corresponding tool, the two push rods 10 can be pushed into the housing 6 of the device 1 to move the test specimen holders 9 out in the direction of the cylinder bore coating 3. After the test specimens 2 have been pressed against the cylinder bore coating 3 in this way, a conical shaft 13 can be inserted into the housing 6 in the longitudinal direction of the housing, as shown in particular in Fig. 7, in such a way that a conical formation 14 can be positioned on the conical shaft 13 in the region of an end of each test specimen holder 9 facing away from the cylinder bore coating 3.

[0024] By progressively inserting the conical shaft 13 into the housing 6, an increasing force is exerted on the respective test specimen holder 9 by means of the respective conical formation 14 and, via this, on the respective test specimen 2 in the direction of the cylinder bore coating 3. In order to be able to precisely control this force introduction and thus exert an adjustable adhesive force on the test specimens 2 so that the test specimens 2 can be pressed against the cylinder bore coating 3 with a predetermined adhesive force, the conical shaft 13 and the housing 6 expediently have corresponding threads so that the conical shaft 13 can be progressively moved into the housing 6 by a screwing movement.

[0025] Due to this design, the device 1 enables a position-oriented positioning of the test specimens 2 and an introduction of an adjustable adhesive force through the central push rods 10, which can be easily operated from outside the cylinder bore 5, as well as through the conical shaft 13. In this way, the device 1 enables a stabilization of measurement results and an increase in measurement accuracy as well as a reduction in measurement effort.

[0026] By means of the conical shaft 13, the test specimens 2 are to be fixed in their position and pressed against the cylinder bore coating 3 via the test specimen holders 9, so that the device 1, together with the cylinder crankcase 4, can be easily introduced into a curing oven in order to cure an adhesive by means of which the test specimens 2 are to be attached to the cylinder bore coating 3. The device 1 is then to be removed from the cylinder crankcase 4, whereby the conical shaft 13 is first loosened and removed from the housing 6 and then the test specimen holders 9 are to be retracted, i.e. into the housing 6, by pulling the push rods 10 in the opposite direction, i.e. in the direction out of the housing 6.Once the test specimen holders 9 have been detached from the test specimens 2 attached to the cylinder bore coating 3 in this way, the retaining plate 7 must be detached from the cylinder crankcase 4 by removing the fixing screws 8, and the device 1 must be removed from the cylinder bore 5. The cylinder bore coating 3 must now be tested using the test specimens 2 attached to it.

[0027] In the method for arranging the test specimens 2 on the cylinder bore coating 3 of the cylinder crankcase 4 of the internal combustion engine using the device 1, the test specimens 2 to be fastened to the cylinder bore coating 3 are inserted into the respective test specimen holder 9 of the device 1. Thereafter, a sealing ring 15, which is preferably designed as a so-called V-ring, is preferably arranged on the respective test specimen 2 in such a way that it surrounds the edge of a contact surface of the test specimen 2 to be fastened to the cylinder bore coating 3.

[0028] The adhesive is now applied in a metered amount to the contact surface of the respective test specimen 2, for example using a dosing unit. The housing 6 of the device 1 is then inserted into the cylinder bore 5 of the cylinder crankcase 4 and fastened to the cylinder crankcase 4 by means of the holding plate 7 of the device 1 by screwing in the fixing screws 8. In order to prevent the adhesive from dripping from the contact surfaces of the test specimens 2, the cylinder crankcase 4 is preferably aligned such that the cylinder bore axis is horizontal and that the device 1 is inserted into the cylinder bore 5 and fastened to the cylinder crankcase 4 such that the contact surfaces of the test specimens 2 face upwards. In this way, dripping of the adhesive is prevented and an even distribution of the adhesive on the contact surfaces is ensured.

[0029] Once the device 1 has been positioned in the cylinder bore 5 in this way, the test specimens 2 are jointly positioned against the cylinder bore coating 3 by pushing the push rods 10 into the device 1 in the longitudinal direction of the housing and the resulting radial movement of the test specimen holders 9 in the direction of the cylinder bore coating 3. The conical shaft 13 is then inserted into the housing 6 of the device 1. By progressively screwing the conical shaft 13 into the housing 6, the test specimens 2 are pressed against the cylinder bore coating 3 with increasing force via the conical formations 14 of the conical shaft 13, which increasingly press against the respective end of the test specimen holders 9 facing away from the cylinder bore coating 3. In this way, a predetermined contact force or adhesive force is set, with which the test specimens 2 are pressed against the cylinder bore coating 3.

[0030] During this pressing, the adhesive is displaced between the respective contact surface and the cylinder bore coating 3 and tends to escape laterally over an edge of the contact surface. This is prevented, however, by the respective sealing ring 15, which is preferably designed as a V-ring and has a sealing lip that lies flush against the concave surface of the cylinder bore coating 3 to be tested. The sealing ring 15 displaces any excess adhesive further outwards from the edge of the contact surface of the respective test specimen 2. In this way, subsequent manual removal of adhesive that has been displaced laterally and forms a bead at the edge of the contact surface using a hollow milling cutter is no longer necessary.

[0031] This would have to be done when applying test specimen 2 without such a sealing ring so that the test specimen's adhesive surface is not distorted. The adhesive force has a significant impact on the adhesive tensile result and on the scatter of measurement results. If the adhesive surface is too large due to an adhesive bead formed on the side of test specimen 2, an area of ​​cylinder bore coating 3 will be torn off during the adhesive tensile test, which area is larger than the actual contact surface of the respective test specimen 2. This distorts the adhesive tensile result calculated from the quotient of the applied force and the area. By using the sealing rings 15, such laborious removal of excess adhesive is not required, and an exact adhesive tensile measurement is still ensured.

[0032] The conical shaft 13 maintains a constant, predetermined contact force with which the test specimens 2 are pressed against the cylinder bore coating 3. The cylinder crankcase 4 can now be placed together with the fixture 1 into the curing oven, where the adhesive, typically a two-component adhesive, cures at a predetermined temperature of, for example, 200°C. The cylinder crankcase 4 is then removed from the curing oven with the fixture 1, and the fixture 1 is removed from the cylinder bore 5 in the reverse order.

[0033] This means that the conical shaft 13 is loosened and removed from the housing 6, the push rods 10 are moved in the opposite direction, i.e., pulled out of the housing 6, so that the test specimen holders 9 are retracted into the housing 6 and thereby released from the test specimens 2 attached to the cylinder bore coating 3, the holding plate 7 is released from the cylinder crankcase 4 by removing the fixing screws 8, and the device 1 is removed from the cylinder bore 5. The cylinder bore coating 3 can then be tested directly using the test specimens 2 attached thereto, without any further required work steps.

Claims

[1] Device (1) for arranging at least one test specimen (2) on a cylinder bore coating (3) of a cylinder crankcase (4) of an internal combustion engine, characterized by a housing (6) which can be inserted into a cylinder bore (5) of the internal combustion engine, in which the at least one test specimen (2) is to be arranged, wherein a holding plate (7) is arranged on an upper side of the housing (6), which holding plate can be placed on an upper side of the cylinder crankcase (4) and fastened thereto after the housing (6) has been inserted into the cylinder bore (5), wherein at least one test specimen holder (9) can be moved radially out of the housing (6) in the direction of the cylinder bore coating (3) in order to press the at least one test specimen (2) onto the cylinder bore coating (3). [2] Device according to claim 1, characterized bythat the at least one test specimen holder (9) is coupled to at least one push rod (10) arranged in the housing (6) in the longitudinal direction of the housing in such a way that the at least one test specimen holder (9) can be moved radially by moving the at least one push rod (10) in the longitudinal direction of the housing. [3] Device (1) according to claim 1 or 2, characterized by that a conical shaft (13) is to be arranged or is arranged in the housing (6) in the longitudinal direction of the housing in such a way that a conical formation (14) on the conical shaft (13) is positioned in the region of an end of the at least one test specimen holder (9) facing away from the cylinder bore coating (3). [4] Device (1) according to one of claims 1 to 3, comprising a sealing ring (15) which is arranged on the test body (2) in such a way that it surrounds a contact surface of the test body (2) to be fastened to the cylinder bore coating (3) on the wheel side. [5] Method for arranging at least one test specimen (2) on a cylinder bore coating (3) of a cylinder crankcase (4) of an internal combustion engine using a device (1) according to one of claims 1 to 4, characterized by that at least one test specimen (2) is inserted into a test specimen holder (9) of the device (1), an adhesive is applied to a contact surface of the test specimen (2) to be fastened to the cylinder bore coating (3), a housing (6) of the device (1) is introduced into a cylinder bore (5) of the cylinder crankcase (4) and is fastened to the cylinder crankcase (4) by means of a holding plate (7) of the device (1), and the test specimen (2) is moved radially in the direction of the cylinder bore coating (3) by means of the test specimen holder (9) and pressed onto the latter. [6] Method according to claim 5, characterized bythat the test specimen holder (9) is moved radially by moving at least one push rod (10) arranged in the housing (6) of the device (1) in the housing longitudinal direction and coupled to the test specimen holder (9) in the housing longitudinal direction. [7] Method according to claim 5 or 6, characterized by that a conical formation (14) of a conical shaft (13) is pressed against an end of the test specimen holder (9) facing away from the cylinder bore coating (3) and the test specimen (2) is thereby pressed against the cylinder bore coating (3). [8] Method according to one of claims 5 to 7, characterized by that before the housing (6) of the device (1) is inserted into the cylinder bore (5), a sealing ring (15) is arranged on the test specimen (2) in such a way that it surrounds the edge of the contact surface of the test specimen (2) to be fastened to the cylinder bore coating (3). [9] Method according to one of claims 5 to 8, characterized bythat the cylinder crankcase (4) together with the device (1) is placed in a curing oven in order to cure the adhesive.

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