Tools for welding the optical lens and housing of automotive lamps

Abstract

The present invention relates to a tool (100) for welding an optical lens (5) and a housing (4) of an automobile lamp, comprising a base body (1) and at least one heating element (2) arranged on the base body (1), wherein the heating element (2) can be moved relative to the base body (1) between a rest position and a heating position.

Description

Technical Field

[0001] The invention relates to a tool for welding a light lens and a housing of an automobile lamp. The tool comprises a base body and at least one heating element arranged on the base body. Background Art

[0002] Today, the housing and optical lens of automotive lamps are often made of thermoplastics and joined together, for example, using heating element welding. This joining method is described, for example, in DVS Guideline 2215-1, "Heating Element Welding of Thermoplastic Mouldings in Series Production." Its functional principle is based on plasticizing the joining surfaces of the mouldings using a heating element through contact or non-contact heat radiation, and subsequently welding them together under joining pressure after the heating element is removed.

[0003] For example, DE 10 2016 109 985 A1 discloses a method for welding a light lens and a housing of an automotive lamp, to which end at least one joining area of ​​the light lens and at least one joining area of ​​the housing are heated by heat input so as to produce a molten state of the light lens and housing material in the joining area, the heat input being generated by irradiating the joining area with infrared radiation and welding being performed with the input heat.

[0004] Conventional methods and apparatuses typically use welding tools that include a substantially plate-shaped base body, with heating elements provided on both the top and bottom sides of the base body. These heating elements each mimic the contour of one of the joint surfaces to be heated. This welding tool is positioned in the joint plane between the mating parts, which are received in a receiving tool, to heat the joint surface. Typically, each of the two receiving tools is mounted on a lifting device, by means of which the received mating parts are guided into the heating position by a linear lifting motion, into the working distance of the heating elements of the welding tool, or, in the case of heating methods based on contact between the joint surface and the heating element, into physical contact.

[0005] A disadvantage of using such welding tools according to the prior art lies in the associated limitations regarding the shape of the mating parts and the arrangement of their joint surfaces. For example, a joint surface arranged in an undercut cannot be heated using a heating element because, when the corresponding mating part approaches the welding tool, physical contact inevitably occurs between the heating element and the section of the mating part that obscures the undercut. Consequently, the heating element and the mating part cannot be brought into the relative position required to heat the joint surface. In particular, in the case of multi-part automotive taillights, increasingly stringent design requirements exist for extremely small gap dimensions between the individual light segments in order to produce the most uniform possible light impression in the thermal image. Consequently, the light components housed in the lamp housing are arranged in close proximity to the edge-circumferential joint surface between the housing and the optical lens. This significantly reduces the accessibility of the housing-side joint surface to welding tools according to the prior art. Summary of the Invention

[0006] The object of the present invention is therefore to provide a method and a device by which the above-mentioned disadvantages of the prior art can be overcome and, in particular, light lenses and lamp housings can be welded when accessibility to the joining surfaces is very limited.

[0007] The object is achieved by using a welding tool.

[0008] The invention includes the following technical teaching: the heating element is arranged displaceably on a base body of the welding tool between a rest position and a heating position.

[0009] The present invention is based on the idea that the movable arrangement of a heating element on a welding tool creates an additional degree of translational freedom. This allows, in conjunction with the linear lifting and lowering movement of a receiving tool known from prior art welding apparatuses, joint surfaces in undercuts or other geometrically restricted arrangements on a mating part to be brought into a suitable heating position relative to the heating element. The direction of movement of the movable heating element can be oriented, for example, at a right angle or at an oblique angle to the lifting axis of the receiving tool (hereinafter referred to as the z-axis), or a right-angled direction of movement can be advantageously combined with a heating element that protrudes at an oblique angle from the welding tool base body. In terms of method technology, when the receiving tool is advanced into the heating position, the movable heating element, for example, remains in its rest position. This rest position is characterized in that the heating element does not collide with a section of the mating part during advancement of the receiving tool. In particular, the rest position can be spaced further laterally from the mating joint surface than the heating position. After the receiving tool has reached the heating position, the heating element can be moved into the heating position, whereby, by guiding the movable heating element laterally in this way, the section of the joining partner which covers the counter-joint surface in the z-axis can be bypassed.

[0010] In one advantageous embodiment of the welding tool according to the invention, the heating element comprises a guide body and a heating resistor accommodated thereon, the guide body being movably mounted on a base body and having an angled and / or curved shape. In this embodiment, the geometric design of the guide body allows the welding tool to be further adapted to complexly shaped joining partners with difficult-to-access joining surfaces. For example, a guide body with an L-shaped cross-section can be suitable for accessing joining surfaces in undercuts.

[0011] For example, the welding tool can comprise a pneumatic cylinder or a servomotor for moving the heating element, which is suitably arranged on the base body and can move the heating element between a rest position and a heating position.

[0012] The base body preferably has a substantially plate-like shape with an underside, the z-direction being defined by a surface normal to the underside and the x-direction being defined by a tangent to the underside, and the heating element being arranged on the underside and movable in a displacement direction that corresponds to the x-direction or whose projections in the x- and z-directions have non-zero components. When such a welding tool is used in a corresponding apparatus, the z-direction is collinear with the z-axis of the lifting device. The heating element is displaced, for example, tangentially to the underside of the base body. For this purpose, for example, corresponding guide rails for displaceably receiving a guide body of the heating element can be provided on the base body.

[0013] Furthermore, it can be advantageous to combine a movable heating element with a fixed heating element known from the prior art on the soldering tool. Thus, in the above-described embodiment, a second heating element is accommodated on the underside of the base body, and the movable heating element and the second heating element, when in the heating position, can jointly simulate the contour of the joint surface of the lamp housing. This is advantageous if access to the joint surface of the housing is only partially obstructed, while the remaining sections can be accessed by conventional heating elements by a purely linear approach in the z-direction to the working distance required for heating.

[0014] In another embodiment, a third heating element is provided on the upper side of the plate-shaped base body, opposite the lower side, by which the contour of the joining surface of the light optic is simulated. This welding tool can be used to weld together a lamp housing and a light optic having a joining surface that is at least partially inaccessible.

[0015] The underside of the plate-like base preferably has an inclined partial surface whose surface normal projections in the x- and z-directions have non-zero components, and the movable heating element is accommodated on this partial surface. The purpose of this design is to maintain the movable heating element in its rest position or to move it there by gravity. To this end, the welding tool according to the present invention is positioned in the welding apparatus so that gravity acts in the z-direction, i.e., the underside of the plate-like base faces the ground. Accordingly, the inclined partial surface on which the movable heating element is accommodated is oriented so that the heating element is at a smaller distance from the ground in the rest position than in the heating position. In the absence of other forces, the heating element is thus accelerated in the direction of the rest position or held there by gravity.

[0016] The present invention also relates to a device for welding an optical lens and a housing of an automobile lamp, the device comprising at least:

[0017] - a lower receiving tool for the lamp housing,

[0018] - Upper receiving tool for optical lenses,

[0019] - a welding tool according to the invention with a plate-shaped basic body in one of the aforementioned embodiments,

[0020] - a lifting device for moving the lower receiving tool and the upper receiving tool into the heating position and the welding position, respectively, and

[0021] - A device for moving the welding tool into the joint plane between the first receiving tool and the second receiving tool. The lifting device operates along the z-axis and the welding tool is moved in laterally, ie, along an axis substantially perpendicular to the z-axis.

[0022] Preferably, the apparatus comprises a welding tool having an inclined partial surface according to the above embodiment, and the lower receiving tool comprises a rigid guide element configured to move a movable heating element on the welding tool into the heating position when the lower receiving tool is moved into the heating position. When the lower receiving tool is advanced, the guide element comes into physical contact with the heating element in the rest position and, as the lower receiving tool is advanced further, carries it along, so that when the lower receiving tool assumes the heating position, the heating element is exactly in the heating position.

[0023] The present invention also relates to a method for welding an optical lens and a housing of a vehicle lamp by means of the device according to the invention, said method comprising at least the following method steps:

[0024] - receiving the housing in the lower receiving tool in the initial position and receiving the optical lens in the upper receiving tool,

[0025] - moving the welding tool into the joining plane between the housing and the light optic, with the bottom side of the base body facing the joining surface of the housing, the top side of the base body facing the joining surface of the light optic and the movable heating element in the rest position,

[0026] - lifting the lower receiving tool and lowering the upper receiving tool to the corresponding heating position,

[0027] - moving the movable heating element into the heating position,

[0028] - heating and plasticizing the joint surface of the housing and the optical lens by means of a heating element,

[0029] - moving the movable heating element into a rest position,

[0030] - lowering the lower receiving tool from the corresponding heating position and raising the upper receiving tool,

[0031] - Remove the welding tool,

[0032] - raising the lower receiving tool and lowering the upper receiving tool to the welding position, in which the joint surfaces of the housing and the optical lens are pressed against each other under a joining pressure, and waiting for the cooling time of the joint surfaces,

[0033] - lowering the lower receiving tool and raising the upper receiving tool from the welding position, and

[0034] - Remove the welded connection unit formed by the housing and the optical lens.

[0035] When using a welding system with a rigid guide rod on the lower receiving tool, the heating element is synchronously moved into the heating position while the lower receiving tool is raised to the heating position, and when the lower receiving tool is lowered, the heating element is moved into the rest position by gravity. As an alternative to this gravity-based positioning, movement by guide rods with a pneumatic or spring-loaded return mechanism can also be used. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other measures for improving the present invention will be described in detail below with reference to the accompanying drawings in conjunction with the preferred embodiments of the present invention. The accompanying drawings are as follows:

[0037] Figure 1 shows a cross-sectional view of a section of a two-piece taillight having an access-limited weld connection;

[0038] Figure 2a 、 2b Shows a top view of a welding tool according to the present invention; and

[0039] Figure 3a 、 3bA cross-sectional view of a device according to the invention and a section of a taillight housing accommodated thereon is shown. DETAILED DESCRIPTION

[0040] Figure 1 A cross-sectional view of a section of a two-part taillight with limited-access welded connections 45, 45' is shown to illustrate the object on which the present invention is based. The two-part taillight comprises a fender light A and a tailgate light B, each having a light housing 4, 4', a light optic 5, 5' and light-technical components 7, 7'. The sections of the light optics 5, 5' extending upward in the plane of the drawing form the rear ends of the taillight sections A and B, so that Figure 1 The cross sections shown in are horizontal sections.

[0041] Modern taillights require that the distance AB between the light functions be as small as possible in order to produce a spatially uniform light impression in the thermal image of the taillight, i.e., when the light function is switched on, which light impression has no noticeable interruptions even in the transition area between the fender light A and the tailgate light B. To minimize the distance AB, the light-technology components 7, 7' should be arranged in the housing 4, 4' such that they are in almost physical contact with the light lenses 5, 5' in the area of ​​the light lenses 5, 5'.

[0042] The welded connection 45, 45' between the housing 4, 4' and the light lens 5, 5' will therefore be almost covered by the optical technology component 7, 7'. The distance between the welded connection 45, 45' and the rear section of the light lens 5, 5' extending upward in the plane of the drawing can typically be up to 40 mm to ensure that the light function is visible even when the taillight is viewed from the side. When the joint surface is plasticized by thermal radiation, the distance between the joint surface extending in the welded connection 45, 45' shown here and the heating element used is typically 2 mm. Infrared heating elements according to the prior art include linear or strip-shaped heating resistors, which are accommodated in a guide body. The thickness of such a heating element is significantly greater than the thickness of the light lens 5, 5'. Therefore, in the case shown, even when a welding method based on contactless heating is used, the accessibility of the joint surface on the housing side to the corresponding heating element is greatly limited by the protruding optical technology component 7, 7'. If the heating element is guided to the housing-side joint surface by a linear lifting movement in a direction extending vertically from top to bottom in the plane of the drawing, as is common in welding devices of the prior art, the required working distance of approximately 2 mm cannot be achieved because the heating element would collide with the section of the light-technical component 7, 7' that protrudes from the joint surface. Therefore, it is not possible to produce with welding tools or devices of the prior art. Figure 1 The object underlying the present invention arises from the welded connections 45 , 45 ′ shown in FIG.

[0043] Figure 2a and2b The figure shows a top view, viewed along the z-direction z, onto the underside 10 of a welding tool 100 according to the present invention. The welding tool comprises a plate-like base body 1, a movable heating element 2, and a fixed heating element 2'. The heating elements 2, 2' comprise guide bodies 21, 21' and heating resistors 22, 22' accommodated therein. The heating resistors 22, 22' are made of corrugated metal strips, typically measuring 4 mm wide and 0.8 mm thick. They are designed to emit medium-wave infrared radiation when energized. The heating resistors 22, 22' are embedded in matching recesses on the end faces of the guide bodies 21, 21'. The guide body 21' of the fixed heating element 2' can have a rectangular or trapezoidal cross-section, with a side height, i.e., the distance in the z-direction z between the heating resistor 22' and the underside 10 of the base body 1, up to 50 mm. The guide body 21 of the movable heating element 2 has an L-shaped cross-section, with the underside of one leg of the L visible in the view shown here. The heating element 2 is movable in the x-direction x, for which purpose the guide body 21 is received, for example, on a rail-like sliding guide 13 on the underside 10 of the base body 1 .

[0044] Figure 2a The movable heating element 2 is shown in its rest position, in which it is spaced apart from the fixed heating element 2' in the x-direction x. In this position, the welding tool 100 and the lamp housing to be welded are brought into contact in the z-direction z in the method according to the invention. Parts of the lighting components arranged in the lamp housing that protrude partially beyond the joint surface (see Figure 1 ) can thereby pass through the gap between the movable heating element 2 and the fixed heating element 2 ′ without collision.

[0045] Figure 2b The movable heating element 2 is shown in its heating position, in which it rests against the fixed heating element 2 ′, so that the course of the two heating resistors 22 , 22 ′ simulates the contour of the joining surface of the lamp housing to be welded.

[0046] exist Figure 3a and 3bshows a cross-sectional view of a section of a welding device 200 according to the present invention, comprising a welding tool 100 and a housing 4 for a fender light A. The welding tool 100 comprises a substantially plate-shaped base body 1, the underside 10 of which has an inclined partial surface 12 on which a guide body 21 of a heating element 2 is movably received. An upper heating element 3 comprising a guide body 31 and a heating resistor 32 is arranged on the upper side 11 of the base body 1. This heating element is configured to heat the mating surface of a corresponding optical lens. The welding tool 100 is positioned in the mating plane between the housing 4 and the optical lens. The optical lens and the upper receiving tool of the device 200 that receives it are not shown here. The housing 4, in which the optical component 7 is located, is received in the lower receiving tool of the device 200, which is not shown here.

[0047] Figure 3a The movable heating element 2 is shown in its rest position, in which it is held by gravity. The joint surface 40 of the housing 4 is brought closer to the heating resistor 22 by the lifting movement of the lower receiving tool in the z-direction z, and the rigid guide element 6 provided on the lower receiving tool is also displaced accordingly in the z-direction z. The guide element 6 performs the function of a driver and, starting from the point in time when it contacts the guide body 21, moves the heating element 2 along the inclined partial surface 12 as the lower receiving tool is lifted further. As the housing 4 approaches in the z-direction z, the heating element 2 is moved laterally to the joint surface 40 by a synchronous sliding movement with a movement component in the x-direction x, thereby bypassing the nose-like section of the light-technology component 7 that protrudes beyond the joint surface 40.

[0048] exist Figure 3b In the present embodiment, the lower receiving tool is in the heating position and the movable heating element 2 is in the heating position. This means that the joint surface 40 and the heating resistor 22 are suitably spaced apart from one another in the z-direction z and suitably oriented relative to one another in the x-direction x, allowing heating and plasticizing of the joint surface 40. When the lower receiving tool is subsequently lowered, the contact between the guide body 21 and the guide rod element 6 is broken, causing the guide body 21 to slide down along the inclined partial surface 12 under the action of gravity until the heating element returns to its rest position. Therefore, when the lower receiving tool is lowered, the heating element 2 follows the same trajectory as when it was raised, preventing it from colliding with protruding optical components 7 during descent.

[0049] Instead of using the guide rod element 6 shown here, the heating element 2 can also be moved between the rest position and the heating position by a separate drive on the welding tool 100 , such as a pneumatic drive or a servo motor.

[0050] The implementation of the present invention is not limited to the preferred embodiments presented above. On the contrary, numerous variants are conceivable, which utilize the solutions shown in completely different implementation types. All features and / or advantages disclosed in the description or the drawings, including structural details, spatial arrangements, and method steps, are essential to the present invention both individually and in various combinations.

[0051] Reference Signs List

[0052] 100 welding tools

[0053] 200 welding equipment

[0054] 1 Matrix

[0055] 10 Underside of the substrate

[0056] 11 Upper side of the substrate

[0057] 12 Partial surface of the lower side

[0058] 13 Sliding rails

[0059] 2 removable heating elements

[0060] 2' lower heating element

[0061] 21, 21' guide

[0062] 22, 22' heating resistor

[0063] 3 Upper heating element

[0064] 31 Guide

[0065] 32 Heating resistor

[0066] 4. 4' lamp housing

[0067] 40, 40' joint surface of lamp housing

[0068] 45, 45' welding connection

[0069] 5, 5' optical lens

[0070] 50, 50' optical lens joint surface

[0071] 6 Guide rod

[0072] 7. Internal components of 7' optical technology

[0073] A Fender lights

[0074] B rear cover light

[0075] AB Light Function Distance

[0076] xx direction

[0077] zz direction

Claims

1. A welding tool (100) for welding a light lens (5) and a housing (4) of an automobile lamp, the welding tool comprising a base (1) and at least one heating element (2) arranged on the base (1), characterized in that: The heating element (2) is movable between a rest position and a heating position relative to a base (1), and comprises a guide body (21) and a heating resistor (22) received on the guide body, wherein the guide body (21) is movably arranged on the base (1), and the guide body (21) has an angled and / or curved shape, and the guide body (21) has an L-shaped cross section including a first leg and a second leg, the lower side (10) of the base (1) has an inclined local surface (12), the guide body (21) of the heating element (2) is received on the local surface (12) with the first leg and is movable along the local surface (12), and the heating resistor (22) is arranged on the second leg of the guide body (21).

2. The welding tool (100) according to claim 1, characterized in that The welding tool (100) comprises a pneumatic cylinder or a servo motor, and the heating element (2) can be moved by means of the pneumatic cylinder or the servo motor.

3. The welding tool (100) according to claim 1, characterized in that The base body (1) has a plate-like shape with a bottom side (10), the z direction (z) being defined by a surface normal of the bottom side (10) and the x direction (x) being defined by a tangent on the bottom side (10), and the heating element (2) being arranged on the bottom side (10) and being movable in a movement direction which corresponds to the x direction (x) or a projection of the movement direction onto the x direction (x) and the z direction (z) having a non-zero component.

4. The welding tool (100) according to claim 3, characterized in that A second heating element (2') is accommodated on the underside (10), the contour of the joining surface (40) of the housing (4) being simulated by the movable heating element (2) in the heating position and the second heating element (2').

5. The welding tool (100) according to claim 3 or 4, characterized in that A third heating element (3) is provided on the upper side (11) of the base body (1) opposite the lower side (10), by which the contour of the joining surface (50) of the optical lens (5) is simulated.

6. The welding tool (100) according to claim 3 or 4, characterized in that The projections of the surface normal of the local surface (12) in the x-direction (x) and the z-direction (z) have non-zero components.

7. A device (200) for welding a light lens (5) and a housing (4) of an automobile lamp, the device comprising at least: - a lower receiving tool for the housing (4), - upper receiving tool for optical lens (5), - a welding tool (100) according to claim 5 or 6, - a lifting device for moving the lower receiving tool and the upper receiving tool into the heating position and the welding position, respectively, and - means for moving the welding tool (100) into the joining plane between the first receiving tool and the second receiving tool.

8. The device (200) according to claim 7, characterized in that The device comprises a welding tool (100) according to claim 6, and the lower receiving tool comprises a rigid guide rod member (6) which is configured to move the movable heating element (2) on the welding tool (100) into the heating position when the lower receiving tool is moved into the heating position.

9. A method for welding an optical lens (5) to a housing (4) of a vehicle lamp by means of a device (200) according to claim 7, the method comprising at least the following method steps: - receiving the housing (4) in the lower receiving tool and receiving the optical lens (5) in the upper receiving tool, - moving the welding tool (100) into the joining plane between the housing (4) and the optical lens (5), with the bottom side (10) of the base body (1) facing the joining surface (40) of the housing (4) and the top side (11) of the base body (1) facing the joining surface (50) of the optical lens (5), and the movable heating element (2) in the rest position, - lifting the lower receiving tool and lowering the upper receiving tool into the corresponding heating position, - moving the movable heating element (2) into the heating position, - heating and plasticizing the joint surface of the housing (4) and the optical lens (5) by means of a heating element, - moving the movable heating element (2) into the rest position, - lowering the lower receiving tool from the corresponding heating position and raising the upper receiving tool, - Remove the welding tool (100), - raising the lower receiving tool and lowering the upper receiving tool to the welding position, in which the joint surfaces of the housing (4) and the optical lens (5) are pressed against each other under a joining pressure, and waiting for the cooling time of the joint surfaces, - lower the lower receiving tool and raise the upper receiving tool from the welding position, and - Remove the welded connection unit formed by the housing (4) and the optical lens (5).

10. A method for welding an optical lens (5) to a housing (4) of a vehicle lamp by means of the device (200) according to claim 8, the method comprising at least the following method steps: - receiving the housing (4) in the lower receiving tool in the initial position and receiving the optical lens (5) in the upper receiving tool, - moving the welding tool (100) into the joining plane between the housing (4) and the optical lens (5), wherein the bottom side (10) of the base body (1) faces the joining surface (40) of the housing (4), the top side (11) of the base body (1) faces the joining surface (50) of the optical lens (5), and the movable heating element (2) is in the rest position, - the lower receiving tool is raised and the upper receiving tool is lowered to the corresponding heating position, wherein the movable heating element (2) is moved into the heating position by means of the rigid guide element (6), - heating and plasticizing the joint surface of the housing (4) and the optical lens (5) by means of a heating element, - lowering the lower receiving tool from the corresponding heating position and raising the upper receiving tool, whereby the movable heating element (2) moves into the rest position by means of gravity, - Remove the welding tool (100), - raising the lower receiving tool and lowering the upper receiving tool to the welding position, in which the joint surfaces of the housing (4) and the optical lens (5) are pressed against each other under a joining pressure, and waiting for the cooling time of the joint surfaces, - lower the lower receiving tool and raise the upper receiving tool from the welding position, and - Remove the welded connection unit formed by the housing (4) and the optical lens (5).

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