Device and method for producing a notch for stripping insulation

Abstract

A device for forming a notch for stripping comprises a cutting mechanism including an electrically conductive cutting blade; a contact detection section for detecting contact between an outermost conductor of the sheathed electrical conductor and the cutting blade based on a variable capacitance between the outermost conductor and the cutting blade; and a movement mechanism for adjusting the position of the cutting blade and thus positioning the cutting blade in a position corresponding to a specific notch depth for forming the notch when the contact detection section detects contact between the cutting blade and the outermost conductor during the movement of the cutting blade.

Description

Background of the inventionTechnical field

[0001] The present invention relates to a device and a method for forming a notch for stripping, in which the notch is formed starting from an outer surface of a covered electrical wire for stripping the covered electrical wire. State of the art

[0002] As one of the conventional methods for processing terminals of covered electric wires, a stripping method in which a coating is removed to expose an inner conductor such as a core is often used. Furthermore, a stripping notch forming apparatus is known that forms a notch in the covered electric wires from the outer surface of the casing to make a stripped portion removable (see, for example, Patent Document 1). Such a stripping notch forming apparatus according to Patent Document 1 includes a pair of V-shaped cutting blades configured to pinch a covered electric wire therebetween to penetrate the outer surface and then rotate around an electric line axis of the covered electric wire to form the stripping notch. Citation listPatent literature

[0003] Patent Document 1: JP 2000-350324 A Summary of the invention

[0004] Covered electrical wires comprise a thick electrical wire comprising multiple layers of coating materials arranged and stacked around a core, such as an inner coating, a braid, a metal foil, and an outer coating. In many cases, this type of stripping notch forming device is configured to use the axis of the electrical wire as a reference point for the movement of the V-shaped cutting blades to clamp the covered electrical wires with the V-shaped cutting blades, and the target positions to be reached by the V-shaped cutting blades are determined as a distance from the axis of the electrical wire.Then, the V-shaped cutting blades are moved toward the axis of the electrical wire to clamp the covered electrical wires, causing the V-shaped cutting blades to penetrate them to a notch depth corresponding to the specified target positions. For example, when forming a notch in a thick electrical wire as mentioned above, the target positions for the V-shaped cutting blades are determined as the distance from the axis of the electrical wire obtained by subtracting a thickness of a coating material to be removed from a sum of a radius of a core and individual thicknesses of the multiple layers of coating materials.For a thick electrical wire, a tolerance in the target positions for the V-shaped cutting blades with the electrical wire axis as a reference tends to be large because this tolerance is a cumulative tolerance obtained from a core radius tolerance and a thickness tolerance of one or more coating materials different from the removed coating material. This may result in poor accuracy in the movement of the V-shaped cutting blades. For example, when forming a notch for a desired coating material in a thick electrical wire, the notch may be formed too deep due to the poor movement accuracy of the V-shaped cutting blades, so that the notch protrudes into a further inner coating material that should remain untouched. A notch may also be formed too shallow, so that the notch is insufficient for stripping.

[0005] In addition, many covered electrical wires are wound on spools for storage. During such storage, the core and / or sheath may be deformed and flattened due to the stress of their own weight, or misalignment may occur in which the axis of the electrical wire may be offset from the center of the covered electrical wire. When a notch with such deformation and / or misalignment is applied to a covered electrical wire by the above-described stripping notch forming apparatus, the rotation of the pair of V-shaped cutting blades about the axis of the electrical wire may result in a different notch depth achieved by the cutting blades in a direction about the axis of the electrical wire.As a result, the notch obtained may be too deep in some areas along the direction around the axis of the electrical line, allowing an inner, untouched portion to be cut, while in other areas along the direction around the axis of the electrical line, the notch may be too shallow, allowing the electrical line to be insufficiently cut.

[0006] Thus, in the above-mentioned type of notch forming apparatus for stripping, namely, an apparatus having a pair of V-shaped cutting blades that clamp a covered electric wire and are then rotated around the axis of the electric wire, there is a problem that the accuracy of forming the notch may be reduced when forming a notch in a thick electric wire and a covered electric wire wound around a reel for storage.

[0007] Therefore, the present invention focuses on the above problem, and an object of the present invention is to provide an apparatus and a method for forming a notch for stripping, which enable improvement in the accuracy of forming the notch in the case of forming a notch in a thick electric wire and / or a covered electric wire wound around a reel for storage.

[0008] To achieve the above-mentioned objective, an apparatus for forming a notch for stripping comprises: one or more cutting mechanisms comprising one or more mechanism parts, wherein each of the one or more cutting mechanisms is associated with one of the one or more mechanism parts, wherein the one or more mechanism parts are configured to be arranged around an axis of a covered electrical wire, wherein the covered electrical wire comprises a core covered with an insulating layer or covered with the insulating layer and one or more conductive layers, wherein the one or more conductive layers are layered within the insulating layer, wherein each of the one or more cutting mechanisms is configuredthat it forms, by means of a respective one of the one or more mechanism parts, one or more notches in the covered electric wire up to a certain notch depth starting from an outer surface of the covered electric wire; and a rotating mechanism configured to rotate the one or more mechanism parts about the axis of the electric wire and thus expand the one or more notches in a direction about the axis of the electric wire in a state of the one or more mechanism parts having formed the one or more notches in the covered electric wire, which makes a stripped area corresponding to the notch depth removable, wherein each of the one or more cutting mechanisms comprises: an electrically conductive cutting blade movable in a cutting direction that cuts the outer surface; a contact detection section configured todetecting contact between an outermost conductor and the cutting blade based on a variable capacitance between the outermost conductor and the cutting blade, wherein the outermost conductor is located at a minimum depth from the outer sheath surface in the sheathed electrical cable, and the variable capacitance depends on the movement of the cutting blade; and a moving mechanism that, together with the cutting blade, forms one of the one or more mechanism parts, wherein the moving mechanism is configured to move the cutting blade in the cutting direction. Upon detection of the contact by the contact detection section during movement of the cutting blade, the moving mechanism is configured to adjust a position of the cutting blade in the cutting direction and position the cutting blade in a position corresponding to the notch depth to form one or more notches therein.

[0009] To achieve the above-mentioned object, the present invention also provides a method for forming a notch for stripping, comprising: a preparation step in which the covered electric wire is placed in the jig as described above, and the cutting blade is moved to an initial position by the jig, the initial position being spaced apart from the outer surface of the sheath in the cutting direction; a first notch forming step in which the cutting blade is moved until contact between the outermost conductor and the cutting blade is detected by the contact detecting section based on the variable capacitance;Upon detection of contact by the contact detection section during movement of the cutting blade according to the first notch forming step, a second notch forming step of adjusting the position of the cutting blade in the cutting direction and placing the cutting blade in a position corresponding to the notch depth to form one or more notches therein; and a rotating step of rotating the one or more mechanism parts around the axis of the electric wire and thereby expanding the one or more notches in the direction around the axis of the electric wire in the state of the one or more mechanism parts having formed the one or more notches in the covered electric wire, thereby making the stripped portion corresponding to the notch depth removable.

[0010] With the apparatus and method for forming a notch for stripping, it is possible to improve the accuracy of forming a notch when forming a notch in a thick electric wire and / or a covered electric wire wound around a spool for storage. Short description of the drawings Fig. 1 shows a schematic view of an apparatus for forming a notch for stripping according to an embodiment; Fig. Figure 2 shows a schematic view of a sheathed electrical cable on which the device for forming a notch for stripping according to Fig. 1 notching can be carried out; Fig. 3 shows a sectional view of the sheathed electrical cable according to Fig. 2 along the line V11-V11 Fig. 2; Fig. Figure 4 shows a schematic side view of a mechanism part of a cutting mechanism according to Fig. 1, viewed in one cutting direction; Fig. Figure 5 shows schematically how a contact detection section according to Fig. 1 detects the contact of cutting blades with a metal foil based on a variable capacitance between the metal foil and the cutting blades; Fig. 6 shows schematically a clamping part according to Fig. 5; Fig. Figure 7 shows a schematic diagram showing the configuration for contact detection of the cutting blades according to Fig. 5 illustrates; Fig. Fig. 8 is a schematic flowchart showing a flow of a series of processes of a method for forming a notch for stripping at a terminal of a covered electric wire by means of the notch forming apparatus for stripping as shown in Fig. 1 shown; and Fig. Fig. 9 is an explanatory view for explaining some of the processes of the method for forming a notch for stripping according to Fig. 8 by means of a peripheral structure around the cutting blades, as in the side view of Fig. 4 shown. Detailed description of the preferred versions

[0011] Embodiments of an apparatus and method for forming a notch for stripping are described below.

[0012] Fig. 1 shows a schematic view of an apparatus for forming a notch for stripping according to an embodiment. Fig. Figure 2 shows a schematic view of a sheathed electrical cable in which the device for forming a notch for stripping as in Fig. 1 shown a notch formation can be made, and Fig. 3 shows a sectional view of the sheathed electrical cable according to Fig. 2 along the line V11-V11 as in Fig. 2 shown.

[0013] First, a covered electric wire 2 to which notching is applied according to the present embodiment is a thick electric wire including a plurality of layers of coating materials and a conductive core 21 covered with the plurality of layers of coating materials. This covered electric wire 2 is wound around a reel for storage and used for, for example, a high-voltage wire harness for an automobile. As coating materials, the covered electric wire 2 includes an inner coating 22 made of an insulating resin as an insulating layer, a braid 23 as a conductive layer, a metal foil 24 as a conductive layer, and an outer coating 25 made of an insulating resin as an insulating layer.For processing a terminal of the covered electrical wire 2, the device 1 for forming a notch for stripping is configured to form one or more notches up to a certain notch depth starting from an outer surface 2a of the covered electrical wire 2, wherein a stripped area corresponding to the notch depth is removable.

[0014] For example, notching is possible as described below: For example, a notching process is possible in which a depth extending to an inner circumference of the metal foil 24 is specified as the notch depth, so that the outer coating 25 and the metal foil 24 are defined as the stripped area, and one or more notches are formed extending to the inner circumference of the metal foil 24. In this example, the braid 23 is exposed after stripping at a terminal of the covered electric wire 2, the braid 23 accommodating the inner coating 22 and the core 21 therein.Furthermore, as another example, a notch forming process is possible in which a depth extending to an inner periphery of the inner coating 22 is specified as the notch depth, so that all coating materials except the core 21 are defined as the stripped area, forming one or more notches extending to the inner periphery of the inner coating 22. In this example, the core 21 is exposed at the terminal of the covered electric wire 2 after stripping.

[0015] The stripping notch forming apparatus 1 is capable of forming such a notch in the covered electric wire 2 and includes three cutting mechanisms 11 and one rotating mechanism 12. The cutting mechanisms 11 include a plurality of mechanism parts 11a (three mechanism parts 11a in the present embodiment) in a one-to-one manner, that is, each of the cutting mechanisms 11 is associated with one of the mechanism parts 11a, and the mechanism parts 11a are arranged around an axis 2b of the covered electric wire 2. The cutting mechanisms 11 are configured to form one or more notches up to a predetermined notch depth from the outer surface 2a of the covered electric wire 2 by means of the respective mechanism parts 11a.In the present embodiment, the three mechanism parts 11a of the cutting mechanisms 11 are arranged at an angle of 120° around the axis 2b of the covered electric wire and spaced from each other. The rotating mechanism 12 is configured to rotate the three mechanism parts 11a in a cutting rotation direction D11 around the axis 2b of the covered electric wire, thus expanding the one or more notches in the cutting rotation direction D11 around the axis 2b of the covered electric wire in a state where the mechanism parts 11a have formed the one or more notches in the covered electric wire 2. In the present embodiment, the rotating mechanism 12 rotates the three cutting mechanisms 11 by an angle greater than or equal to 120° in the cutting rotation direction D11 around the axis 2b of the covered electric wire.This rotation connects the notches at three locations in the direction around the axis 2b of the covered electric wire to obtain a notch extending over the entire circumference of the covered electric wire 2, whereby the stripped area corresponding to the specified notch depth is removable.

[0016] In the stripping notch forming device 1, the three cutting mechanisms 11, including the mechanism parts 11a, are configured identically. The configuration of the cutting mechanisms 11 will be described below with reference to one of the cutting mechanisms 11.

[0017] Fig. Figure 4 shows a schematic side view of a mechanism part of a cutting mechanism according to Fig. 1, seen in one cutting direction.

[0018] As in the Fig. 1 and Fig. 4, the cutting mechanism 11 comprises a cutting blade 111, a moving mechanism 112, and a contact detection section 113, wherein the cutting blade 111 and the moving mechanism 112 form a mechanism part 11a, wherein the contact detection section 113 is configured to detect a contact between an outermost conductor and the cutting blade 111, wherein the outermost conductor is located at the shallowest depth from the outer sheath surface 2a in the covered electric wire 2. In the present embodiment, in which notching is applied to the covered electric wire 2 as shown in FIGS. Fig. 2 and Fig. 3, the outermost conductor is the metal foil 24.

[0019] The cutting blade 111 is an electrically conductive and disc-shaped cutting element movable in a cutting direction D12 that intersects the outer surface 2a of the covered electrical wire 2. According to the present embodiment, the moving mechanism 112 includes a cutting coupling frame 112b, as described below, wherein the cutting blade 111 is mounted on the cutting coupling frame 112b such that the cutting blade 111 is pivotable about a cutting axis 111a that runs along the axis 2b of the electrical wire and intersects the cutting direction D12.

[0020] The moving mechanism 112 is configured to move the cutting blade 111 in the cutting direction D12. Furthermore, when contact between the cutting blade 111 and the metal foil 24 is detected by the contact detection section 113 during the movement of the cutting blade 111, the moving mechanism 112 adjusts a position of the cutting blade 111 in the cutting direction D12 and positions the cutting blade 111 at a position corresponding to the notch depth for forming a notch in the covered electric wire 2. The moving mechanism 112 according to the present embodiment includes a servo motor 112a as a drive source, and the servo motor 112a can enable precise driving.Furthermore, the moving mechanism 112 includes a cutting clutch frame 112b driven by the servo motor 112a in the cutting direction D12, with the cutting blade 111 pivotally mounted on a tip end of the cutting clutch frame 112b facing the covered electric wire 2. The moving mechanism 112 precisely moves the cutting blade 111 through the cutting clutch frame 112b by means of the servo motor 112a to move the cutting blade 111 to the specified notch depth into the outer surface 2a of the covered electric wire 2.

[0021] As described above, the contact detection section 113 is configured to detect the contact of the cutting blade 111 with the metal foil 24, and this contact detection is performed based on a variable capacitance between the metal foil 24 and the cutting blade 111, which depends on the movement of the cutting blade 111.

[0022] Fig. Figure 5 shows schematically how a contact detection section according to Fig. 1 detects the contact of cutting blades with a metal foil based on the variable capacitance between the metal foil and the cutting blades. Fig. 6 shows schematically a clamping part according to Fig. 5, and Fig. Figure 7 shows a schematic diagram showing the configuration for contact detection of the cutting blades according to Fig. 5 illustrates.

[0023] The clamping part 13 is an electrically conductive member configured to hold the covered electric wire 2 by contacting the outer surface 2a in a clamping position P12, wherein the clamping position P12 is spaced from a notch formation position P11 of the cutting blade 111 in the longitudinal direction D13 of the covered electric wire 2. A clamping part 13 is provided for the three cutting mechanisms 11 and configured to use a pair of clamping elements 131 to hold and clamp the covered electric wire 2 in its radial direction D14, as shown in Fig. 6, wherein both clamping elements 131 are electrically conductive. Each of the clamping elements 131 has an electric wire receiving recess 131a formed on a side facing the covered electric wire 2, wherein the electric wire receiving recess 131a is recessed in a V-shape. The pair of clamping elements 131 holds the covered electric wire 2 by receiving it in the electric wire receiving recesses 131a, so that the clamping elements 131 come into contact with the outer surface 2a of the covered electric wire 2 on the inner surfaces of the electric wire receiving recesses 131a.

[0024] As described above, each of the cutting blades 111 of the three cutting mechanisms 11 and the pair of clamping elements 131 constituting the clamping part 13 are electrically conductive. One of the clamping elements 131 is connected to an IN terminal 113a of the contact detection section 113 of each of the three cutting mechanisms 11, and the cutting blade 111 of each of the cutting mechanisms 11 is connected to an OUT terminal 113b of a corresponding contact detection section 113. With such a connection, a clamp-side capacitor C1 is formed between the clamping element 131 of the clamping part 13, which is connected to the IN terminal 113a, and the metal foil 24, which is the outermost conductor in the covered electric wire 2. Since a distance between the clamping element 131 and the metal foil 24 does not change during clamping, a capacitance of the clamp-side capacitor C1 is a fixed capacitance having a substantially constant value.On the other hand, a cutting-side capacitor C2 is formed between the cutting blade 111 and the metal foil 24. A capacitance of the cutting-side capacitor C2 is a variable capacitance whose value changes with the movement of the cutting blade 111 and the resulting change in the distance from the metal foil 24. When the cutting blade 111 contacts the metal foil 24, the variable capacitance has a value of substantially zero. According to the present embodiment, an electrical circuit CR1 is formed by the IN terminal 113a and the OUT terminal 113b of the contact detection section 113, the clamp-side capacitor C1, the cutter-side capacitor C2, and the metal foil 24 between the two capacitors.The contact detection section 113 applies an alternating voltage between electrodes formed by the cutting blade 111 and the clamping element 131 of the clamping part 13 to detect the variable capacitance in the cutter-side capacitor C2. The alternating voltage is applied between the electrodes via the IN terminal 113a and the OUT terminal 113b. Based on a detection result, specifically, when the variable capacitance of the cutter-side capacitor C2 has a value of zero, the contact detection section 113 detects contact between the cutting blade 111 and the metal foil 24.

[0025] When contact is detected during the movement of the cutting blade 111 by the contact detection section 113, the moving mechanism 112 of each cutting mechanism 11 adjusts the position of the cutting blade 111 in the cutting direction D12 to move the cutting blade 111 to the position corresponding to the specified notch depth. In the case of a specified notch depth extending to the metal foil 24, this means that the moving mechanism 112 stops the movement of the cutting blade 111 at the time of contact detection. In the case of a specified notch depth extending to the braid 23, on the other hand, the moving mechanism 112 stops the movement of the cutting blade 111 when the cutting blade 111 has advanced a distance corresponding to a thickness of the metal foil 24 after the time of contact detection.For a notch depth that reaches the inner coating 22, the movement mechanism 112 stops the movement of the cutting blade 111 when the cutting blade 111 has advanced a distance after the time of contact detection that corresponds to the sum of the thicknesses of the metal foil 24 and the braid 23. For a notch depth that extends to the core 21, the movement mechanism 112 stops the movement of the cutting blade 111 when the cutting blade 111 has advanced a distance after the time of contact detection that corresponds to the sum of the thicknesses of the metal foil 24, the braid 23, and the inner coating 22.Once the notches have been formed in this way at three locations with an angular pitch of 120° around the electric wire axis 2b in the covered electric wire 2 to the specified notch depth, the rotating mechanism 12 rotates the mechanism parts 11a including the cutting blades 111 by an angle greater than or equal to 120° around the electric wire axis 2b. With this rotation, the notches at the three locations are extended in the direction around the electric wire axis 2b to be connected to each other, so that a notch is formed that extends over the entire circumference of the covered electric wire 2 in the direction around the electric wire axis 2b. Through this notch formation process, the stripped area can be made removable according to the specified notch depth.

[0026] Next, a stripping notch forming method will be described, in which a stripping notch is formed at a terminal of the covered electric wire 2 using the stripping notch forming apparatus 1 as described above. Although the following description will repetition some of the above descriptions, the following description will be made with reference to other figures.

[0027] Fig. Fig. 8 is a schematic flowchart showing a flow of a series of processes of a method for forming a notch for stripping at a terminal of the covered electric wire by means of the notch forming apparatus for stripping as shown in Fig. 1 shown illustrates. Fig. Fig. 9 is an explanatory view for explaining some of the processes of the method for forming a notch for stripping according to Fig. 8 by means of a peripheral structure around the cutting blades, as in the side view of Fig. 4 shown.

[0028] The process of the method for forming a notch for stripping according to Fig. 8 is started when the covered electric wire 2 is prepared by forming a notch. When the series of processes is started, a preparation step S11 is first performed. In the preparation step S11, the covered electric wire 2 is placed in the jig 1, and in each of the mechanism parts 11a of the three cutting mechanisms 11, the cutting blade 111 is positioned at an initial position P13, the initial position P13 being spaced from the outer casing surface 2a in the cutting direction D12. At this time, the covered electric wire 2 is placed in the jig 1 by holding the covered electric wire 2 with the clamping part 13.

[0029] The preparation step S11 is followed by a first notch formation step S12, in which the cutting blades 111 are moved in the cutting direction D12 by the moving mechanism 112, as described below. During the first notch formation step S12, a cutting movement step S121 and a contact determination step S122 are repeated, wherein the contact determination step S122 is performed based on the variable capacitance of the cutting-side capacitor C2. In the contact determination step S122, the contact detection section 113 determines whether the variable capacitance of the cutting-side capacitor C2 is zero or not. If the variable capacitance is not zero (NO determination), this indicates that the cutting blade 111 is not in contact with the metal foil 24 as the outermost conductor, and the cutting movement step S121 is therefore repeated.If the variable capacitance is zero (YES determination), this indicates that the cutting blade 111 is in contact with the metal foil 24, and therefore the process proceeds to a next step, ie, a second notch forming step S13.

[0030] After the contact between the cutting blade 111 and the metal foil 24 is detected by the contact detection section 113, the position of the cutting blade 111 in the cutting direction D12 is adjusted by the moving mechanism 112 in the second notch forming step S13. With this position adjustment, the cutting blade 111 is positioned at a position corresponding to the specified notch depth t11 to form a notch. In the case of a specified notch depth extending to the metal foil 24, the movement of the cutting blade 111 is stopped at the time of contact detection, as described above. In the case of a specified notch depth extending to the braid 23, on the other hand, the movement of the cutting blade 111 is stopped when the cutting blade 111 has advanced a distance corresponding to a thickness of the metal foil 24 after the time of contact detection.After the contact between the cutting blade 111 and the metal foil 24 is detected, the above-described position adjustment of the cutting blade 111 to form a notch is performed in the second notch forming step S13.

[0031] After the second notch forming step S13 is performed for each of the three cutting mechanisms 11, the notches are finally extended according to a rotating step S14. In the rotating step S14, the mechanism parts 11a of the three cutting mechanisms 11 are rotated by the rotating mechanism 12 by an angle greater than or equal to 120° around the electric wire axis 2b in a state of the mechanism parts 11a having formed the notches in the covered electric wire 2. With this rotation, the notches at the three locations are extended in the direction around the electric wire axis 2b to be connected to each other, so that a notch extending over the entire circumference of the covered electric wire 2 in the direction around the electric wire axis 2b is formed at one terminal of the covered electric wire 2.Forming this notch across the entire circumference makes the stripped area, corresponding to the specified notch depth t11, removable. The series of processes of the stripping notch forming method ends here. Afterward, the removable, stripped area is removed to expose its inner part. The stripped area can be removed manually by an operator or using a special removal device.

[0032] The stripping notch forming apparatus 1 and method according to the above-described embodiment can have one or more effects as follows: According to the present embodiment, to form one or more stripping notches by the cutting blade 111, the contact between the metal foil 24 (outermost conductor) and the cutting blade 111 is detected based on the variable capacitance of the cutter-side capacitor C2 between the metal foil 24 and the cutting blade 111. After the detection, the position of the cutting blade 111 is adjusted to position the cutting blade 111 at a position corresponding to the specified notch depth t11 to form one or more notches at the notch depth t11.According to this configuration, the cutting blade 111 is then advanced from a reference position where the cutting blade 111 has actually come into contact with the metal foil 24 of the covered electric wire 2. By defining the reference for forwarding as described above, it is possible to suppress the effects of accumulated thickness tolerances for individual coating materials and thus improve the accuracy of notching, even when forming a notch in a thick electric wire.Furthermore, even in the case of a covered electric wire 2 with deformation and / or misalignment caused by winding and storage around a spool, since the cutting blade 111 is advanced after the cutting blade 111 is actually brought into contact with the metal foil 24, the effects of the deformation and / or alignment can be suppressed to improve the accuracy of notching. Thus, the present embodiment can enable improvement in the accuracy of notching in the case of forming a notch in a thick electric wire and / or a covered electric wire 2 wound around a spool for storage.Moreover, for a thick electric wire, according to the present embodiment, the specified notch depth t11 can be variably selected as needed, which enables formation of one or more notches in a desired coating material without changing a device structure, and the desired coating material can be selected within a wide range.

[0033] According to the present embodiment, the electrically conductive clamping member 13 is arranged, which is configured to hold the covered electric wire 2 at the clamping position P12, the clamping position P12 being spaced from the notch formation position P11 of the cutting blade 111. The contact detection section 113 is configured to detect the variable capacitance of the cutting-side capacitor C2 by applying a voltage to the electrical circuit CR1, the electrical circuit CR1 including the fixed capacitance of the clamping-side capacitor C1, the variable capacitance, and the metal foil 24. Furthermore, the contact detection section 113 detects the contact between the cutting blade 111 and the metal foil 24 based on the detection result of the variable capacitance.This configuration is preferable because it can make it possible to effectively detect the variable capacitance based on the cutting blade 111 with the electric circuit CR1 formed by the fixed capacitance based on the electrically conductive clamping part 13, the variable capacitance, and the metal foil 24 of the covered electric wire 2.

[0034] Furthermore, the movement mechanism 112 according to the present embodiment includes the servo motor 112a and is configured to move the cutting blade 111 by means of the servo motor 112a. This configuration can enable further improvement in the accuracy of notching by precisely moving the cutting blade 111 with the servo motor 112a.

[0035] It should be noted that the above-described embodiment merely shows representative configurations for the apparatus and method for forming a notch for stripping. The apparatus and method for forming a notch for stripping are not limited thereto, but can be modified and implemented in various ways.

[0036] For example, the above-described embodiment shows the covered electric wire 2 to be used, for example, for a high-voltage wiring harness for an automobile, as an example of a covered electric wire in which a notch for stripping is formed. However, the covered electric wire in which a notch is formed is not limited to this, but the covered electric wire can be used in any specific manner.

[0037] Furthermore, as an example of a covered electric wire in which a notch for stripping is formed, the above-described embodiment shows the covered electric wire 2 in the form of a thick electric wire, which includes the conductive core 21 covered with a plurality of layers of coating materials. As examples of the plurality of layers of coating materials mentioned above, the present embodiment shows the inner coating 22 made of an insulating resin, the conductive braid 23, the conductive metal foil 24, and the outer coating 25 made of an insulating resin.However, the covered electric wire for which a notch is formed is not limited to this, but may include a core covered with a single layer of resin coating. For example, any specific layer structure can be used for the multiple layers of coating materials, even for a thick electric wire. In the case of a simple covered electric wire including the core covered with a single layer of resin coating, the core is the outermost conductor at the shallowest depth from the outer sheath surface.

[0038] As an example of the cutting mechanism, the above-described embodiment shows the three cutting mechanisms 11 comprising the three mechanism parts 11a in a one-to-one arrangement, that is, one of the mechanism parts 11a is assigned to a cutting mechanism 11, the mechanism parts 11a being arranged at an angular interval of 120° around the axis 2b of the covered electric wire 2. However, the cutting mechanism is not limited to this, but any specific number of cutting mechanisms and any specific arrangement for the cutting mechanism can be selected, provided that one or more mechanism parts are arranged around the axis of the covered electric wire.As an example of the stripping notch forming apparatus, the above-described embodiment also shows the stripping notch forming apparatus 1 that holds the covered electric wire 2 by means of the electrically conductive clamping part 13. The contact detection section 113 detects the contact between the cutting blade 111 and the metal foil 24 based on the detection result of the variable capacitance of the cutter-side capacitor C2 in the switching circuit CR1, where the switching circuit CR1 includes the fixed capacitance of the clamp-side capacitor C1, the variable capacitance, and the metal foil 24. However, the stripping notch forming apparatus is not limited to this, but any specific implementation for holding the covered electric wire can be selected, and any specific implementation for detecting the contact between the cutting blade and the outermost conductor can also be selected.However, the variable capacitance of the cutter-side capacitor C2 can be effectively detected by using the electric circuit CR1 including the fixed capacitance of the clamp-side capacitor C1 by holding the covered electric wire 2 with the electrically conductive clamping part 13 as described above.

[0039] As an example of the clamping part, the above-described embodiment also shows the clamping part 13, which holds the covered electric wire by clamping it between the pair of clamping elements 131. However, the clamping part is not limited to this, but any specific holding configuration may be adopted, provided that the clamping part is electrically conductive and holds the covered electric wire.

[0040] As an example of the movement mechanism, the above-described embodiment also shows the movement mechanism 112, which moves the cutting blade 111 by means of the servo motor 112a. However, the movement mechanism is not limited to this; for example, a motor or a cylinder mechanism, which is commonly used as the drive source, can be selected. However, the accuracy of notch forming can be further improved by using the servo motor 112a as the drive source for the movement mechanism 112, as described above.

[0041] Reference character list 1 device for forming a notch for stripping 2 sheathed electrical cables 2a outer surface 2b Axis of the electrical line 11 Cutting mechanism 11a Mechanism part 12 Rotating mechanism 13 Clamping part 21 core 22 Interior coating 23 lichens 24 metal foil 25 Exterior coating 111 cutting blades 111a Cutting axis 112 Movement mechanism 112a servo motor 112b Cutting coupling frame 113 Contact detection section 113a IN terminal 113b OUT connector 131 clamping elements 131a Recesses for accommodating an electrical cable C1 Terminal-side capacitor C2 Cutting-side capacitor CR1 Electrical circuit D11 Cutting direction D12 cutting direction D13 Length direction D14 Radial direction P11 Notch formation position P12 clamping position P13 Starting position S11 Preparation step S12 First notch formation step S13 Second notch formation step S14 Turning step S121 Cutting movement step S122 Contact determination step t11 notch depth QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2000-350324 A

[0003]

Claims

[1] A device (1) for forming a notch for stripping, comprising: one or more cutting mechanisms (11) comprising one or more mechanism parts (11a), wherein each of the one or more cutting mechanisms (11) is associated with one of the one or more mechanism parts (11a), wherein the one or more mechanism parts (11a) are configured to be arranged around an axis (2b) of a covered electrical wire (2), wherein the covered electrical wire (2) comprises a core (21) covered with an insulating layer (22, 25) or is itself covered with the insulating layer (22, 25), and one or more conductive layers (23, 24), wherein the one or more conductive layers (23, 24) are layered within the insulating layer (22, 25), wherein each of the one or more cutting mechanisms (11) is configured,forming one or more notches in the covered electrical wire (2) up to a certain notch depth starting from an outer surface (2a) of the covered electrical wire (2) by means of a respective one of the one or more mechanism parts (11a); and a rotating mechanism (12) configured to rotate the one or more mechanism parts (11a) about the axis (2b) of the electrical wire and thus expand the one or more notches in a direction about the axis (2b) of the electrical wire in a state of the one or more mechanism parts (11a) having formed the one or more notches in the covered electrical wire (2), thereby making a stripped area corresponding to the notch depth removable, wherein each of the one or more cutting mechanisms (11) comprises: an electrically conductive cutting blade (111) movable in a cutting direction (D12) that cuts the outer surface (2a); a contact detection section (113) configured to detect contact between an outermost conductor (24) and the cutting blade (111) based on a variable capacitance between the outermost conductor (24) and the cutting blade (111), wherein the outermost conductor (24) is located at the shallowest depth from the outer sheath surface (2a) in the covered electrical wire (2), and the variable capacitance depends on the movement of the cutting blade (111); and a movement mechanism (112) which, together with the cutting blade (111), forms one of the one or more mechanism parts (11a), wherein the movement mechanism (112) is configured to move the cutting blade (111) in the cutting direction (D12), wherein upon detection of the contact by the contact detection section (113) during the movement of the cutting blade (111), the movement mechanism (112) is configured to adjust a position of the cutting blade (111) in the cutting direction (D12) and to position the cutting blade (111) in a position corresponding to the notch depth for forming one or more notches therein. [2] The device (1) according to claim 1, further comprising: an electrically conductive clamping part (13) configured to hold the covered electrical wire (2) in a clamping position by contacting the outer casing surface (2a), the clamping position being spaced from a notch forming position of the cutting blade (111) in a longitudinal direction of the covered electrical wire (2), wherein the contact detection section (113) is configured to apply a voltage to an electrical circuit (CR1) by using the clamping part (13) and the cutting blade (111) as electrodes to detect the variable capacitance, wherein the electrical circuit (CR1) includes a fixed capacitance between the clamping part (13) and the outermost conductor (24), the variable capacitance, and the outermost conductor (24), wherein the contact detection section (113) is configured to detect the contact based on a detection result of the variable capacitance. [3] The device (1) according to claim 1, wherein the moving mechanism (112) comprises a servo motor (112a), and wherein the moving mechanism (112) is configured to move the cutting blade (111) by means of the servo motor (112a). [4] A method of forming a notch for stripping, comprising: a preparation step (S11) for placing the covered electrical wire (2) in the device (1) according to one of claims 1 to 3 and positioning the cutting blade (111) in an initial position by means of the device (1), the initial position being spaced from the outer casing surface (2a) in the cutting direction (D12); a first notch forming step (S12) for moving the cutting blade (111) until the contact between the outermost conductor (24) and the cutting blade (111) is detected by the contact detecting section (113) based on the variable capacitance; upon detection of the contact by the contact detection section (113) during the movement of the cutting blade (111) according to the first notch forming step, a second notch forming step (S13) for adjusting the position of the cutting blade (111) in the cutting direction (D12) and positioning the cutting blade (111) in a position corresponding to the notch depth to form one or more notches therein; and a rotating step (S14) for rotating the one or more mechanism parts (11a) around the axis (2b) of the electric wire and thus for expanding the one or more notches in the direction around the axis (2b) of the electric wire in the state of the one or more mechanism parts (11a) having formed the one or more notches in the covered electric wire (2), whereby the stripped area corresponding to the notch depth becomes removable.

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