EP3074729A1

EP3074729A1 - Tool for the primary shaping of a housing for a sensor

Info

Publication number: EP3074729A1
Application number: EP14786470.6A
Authority: EP
Inventors: Ulrich Schrader; Manfred Goll; Lothar Biebricher
Original assignee: Continental Teves AG and Co OHG
Current assignee: Continental Teves AG and Co OHG
Priority date: 2013-11-28
Filing date: 2014-10-08
Publication date: 2016-10-05
Also published as: WO2015078628A1; US20160282422A1; CN106415211A; KR20160093035A; DE102013224466A1; US9964603B2

Abstract

The invention relates to a tool (59) for the primary shaping of a housing (56) for a sensor (28) which is designed to capture, via a sensing element (35), a physical area (33) that is dependent on a variable (12) to be measured, and to emit an electrical output signal (42) on the basis of the captured physical area (33), comprising: – a mould cavity (66) for receiving a material (68) that moulds the housing (56), and the sensing element (35), and – a box having a wall that bounds the mould cavity (66), wherein at least a part (60 to 64) of the wall that bounds the mould cavity (66) is mounted in a displaceable manner.

Description

Tool for prototyping a housing for a sensor

The invention relates to a tool for molding a housing for a sensor, a method for using the tool and a sensor with a housing, which is produced by the said method.

From WO 2010/037 810 AI it is known, a sensor of a sensor known, which is adapted to a dependent of a quantity to be measured physical field over the

Detect sensor and output an electrical output signal based on the detected physical field, einhausen in a housing by an injection molding process.

It is an object of the invention to improve the Elnhausen of the known sensor.

The object is solved by the features of the independent claims. Preferred further developments are subject of the dependent claims from ^¬.

According to one aspect of the invention, a tool for patterning a housing for a sensor configured to detect a physical field dependent on a quantity to be measured via a sensor and output an electrical output signal based on the detected physical field comprises a mold space for receiving a housing forming material and the sensor, anda box having a wall bounding the mold space, at least a portion of the wall bounding the mold space being slidably supported. Here, the molding method is particularly preferably a casting ^¬ or injection molding.

The specified tool is based on the consideration that the sensor of the sensor when inserting into the mold space of the tool must rest somewhere on the wall bounding the mold space, since the sensor can not float in the mold space. At the point where the sensor but at of the forming space limiting wall is applied, the

However, sensors are not encapsulated or encapsulated with the housing forming material, whereby the

Sensor of the sensor remains exposed at this point and is exposed to penetrating moisture. This reduces the life of the sensor.

In order to prevent the ingress of moisture, it is proposed in the context of the present invention to make at least a part of the wall bounding the mold space movable. At this movable wall, the sensor can be created in the mold space. If the sensor is then overmolded with the material forming the housing, the wall can be moved away from the sensor, with the material injected or cast into the molding space, which has already or otherwise already hardened, becoming

Holds the sensor. In the resulting space between the sensor and the wegbewegten wall then further material can be poured, so that no exposed point remains on the finished housing, could penetrate through the moisture in the sensor.

In this way, with the specified tool, the life of the sensor can be significantly increased by the avoided penetrating moisture.

In a development of the specified tool, the displaceable part of the wall is designed as a slide, which is movably mounted in relation to the remaining part of the box. Such a slider can be easily controlled to control the wall during the injection molding or casting process. The controlling itself can take place actively or passively. Actively controlling means that an actuator is present, which actively moves the wall away from the sensor. By contrast, passive control means that the wall is moved away from the sensor by the material injected into the mold cavity.

In this case, different inlet or injection channels A ^¬ can be formed on the tool over which the housing forming the Material can be injected or -lassen in the mold space. In this way, the material for forming the housing via a first channel can be admitted when the

Sensor still rests against the wall, wherein the material in the form space now at the location of the other channel on or even hardens, so that the movable wall can be moved by the now penetrating material on the other channel.

In a particular embodiment of the specified tool, the slider is a sliding block. Such a sliding block can be technically easy to manufacture and obstruct the specified tool.

In a particularly preferred embodiment of the specified tool, the mold space is adapted to support the sensor before filling the housing forming material on the sliding wall, so that the movable wall moves away from this after filling the housing forming material and its at least partial curing can be.

According to a further aspect of the invention, a method of using one of the specified tools to manufacture the housing comprises the steps of placing the sensor in the mold space, filling the material in the mold space, moving the movable part of the wall and filling another

Material in the mold space during or after moving the movable part of the wall. Preferably, the material and the further material are the same. In this way, the material and the other material when injecting the other material can mix well with each other, so that no gaps between the individual material layers and the penetration of moisture into the housing is optimally avoided.

In a particular embodiment of the specified method, the material is a thermoplastic. A thermoplastic is a Plastic that can be deformed in a certain temperature range. The process is reversible and can be repeated by cooling and reheating. This utilizes the development of the specified method by at least one upper layer of the first material is reheated and liquefied by the injection of the formed as a thermoplastic further material on the already on or cured first material, whereby the mixing of the two materials at the interface is further promoted.

In a particularly preferred embodiment of the specified method, the additional material has a heat energy during filling into the mold space, with which the previously filled material is at least partially melted, so that an optimal mixing of the two materials is given at the interface.

According to another aspect of the invention, a sensor for detecting a physical field dependent on a quantity to be measured via a sensor and outputting an electrical output signal based on the detected physical field comprises a housing manufactured by one of the specified methods. The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings, in which:

1 is a schematic view of a vehicle with a vehicle dynamics control, FIG. 2 is a schematic representation of a speed sensor in the vehicle of FIG. 1,

Fig. 3 is a schematic representation of a read head of Speed sensor of FIG. 2 in an intermediate production state,

4 shows a schematic representation of an arrangement of the reading head from FIG. 3 in a tool for forming a housing around the reading head, FIG.

5 shows a schematic representation of the arrangement from FIG. 4 in an intermediate state of production of the housing, FIG.

6 shows a schematic representation of the arrangement from FIG. 4 in a further intermediate state of production of the housing, FIG.

Fig. 7 is a schematic representation of the arrangement of Fig. 4 in yet another intermediate state of production of the housing, and

Fig. 8 shows a schematic representation of the fully enclosed reading head of Fig. 3. In the figures, the same technical elements are provided with the same reference numerals and described only once.

Reference is made to FIG. 1, which shows a schematic view of a vehicle 2 with a per se known vehicle dynamics control. Details of this driving dynamics control can be found for example in DE 10 2011 080 789 AI.

The vehicle 2 comprises a chassis 4 and four wheels 6. Each wheel 6 can be slowed down relative to the chassis 4 via a brake 8 fastened fixedly to the chassis 4 in order to slow down a movement of the vehicle 2 on a road (not shown).

It can happen in a manner known to those skilled in that lose the wheels 6 of the vehicle 2 their traction and the vehicle 2 even moves away from a predetermined, for example via a not shown steering wheel trajectory by understeer or oversteer. This is done by itself Known control circuits such as ABS (antilock braking system) and ESP (electronic stability program) avoided.

In the present embodiment, the vehicle 2 for speed sensors 10 on the wheels 6, which detect a rotational speed 12 of the wheels 6. Furthermore, the vehicle 2 has a

Inertialsensor 14 detects the driving dynamics data 16 of the vehicle 2 from which, for example, a pitch rate, a roll rate, a yaw rate, a lateral acceleration, a longitudinal acceleration and / or a vertical acceleration can be output in a manner known to those skilled in the art.

Based on the detected rotational speeds 12 and vehicle dynamics data 16, a controller 18 can determine in a manner known to those skilled, whether the vehicle 2 slips on the road or even deviates from the above-mentioned predetermined trajectory and respond with a known controller output signal 20 to respond. The controller output signal 20 may then be used by an actuator 22 to communicate by means of

Control signals 24 actuators, such as the brakes 8 to control, which respond to the slippage and deviation from the predetermined trajectory in a conventional manner.

The controller 18 may be integrated, for example, in a known motor control of the vehicle 2. Also, the controller 18 and the adjusting device 22 may be formed as a common control device and optionally integrated in the aforementioned engine control. With reference to the wheel speed sensor 10 shown in Fig. 1, the present invention will be clarified in more detail, even if the present invention can be implemented on any electronic devices and in particular on any sensors, such as magnetic field sensors, acceleration sensors, rotation rate sensors, structure-borne sound sensors or temperature sensors.

Reference is made to Fig. 2, which is a schematic view of one of the speed sensors 10 in the vehicle dynamics control of Fig. 1 shows.

The speed sensor 10 is designed in the present embodiment as an active speed sensor, which comprises a non-rotatably mounted on the wheel 6 donor element in the form of an encoder disc 26 and a fixed to the chassis 4 sensor circuit, which is hereinafter referred to as read head 28 for simplicity.

The encoder disk 26 consists in the present embodiment of juxtaposed magnetic north poles 30 and magnetic south poles 32, which together excite a physical field in the form of a donor ^¬ magnetic field 33. This donor magnetic field is indicated in FIG. 3 for the sake of clarity with two field lines shown in dashed lines. If the encoder disk 26 fastened to the wheel 6 rotates with it in a direction of rotation 34, the transmitter magnetic field also rotates with it.

The read head 28 in the present embodiment comprises a sensor in the form of a magnetostriction element 35. The magnetorstriktive member 35 changes depending on the Win ^¬ kellage of the excited magnetic field from the encoder wheel 26. Encoder its electrical resistance. To detect the rotational speed 12, a test signal 39 is applied to the magnetostrictive element 35, which is changed as a function of the angular position of the encoder wheel 26 and thus of the electrical resistance magnetostrictive element 35. Based on this change in the sample ^¬ signal 39 40 evaluates a signal evaluation circuit 12, the rotational speed and outputs it in a data signal 42 to the controller 18 from. This signal evaluation circuit 40 may also be part of the read head 28.

For this purpose and for further background information on active wheel speed sensors, reference is made to the relevant prior art, such as, for example, DE 101 46 949 A1.

Reference is made to FIG. 3, which shows a schematic representation of the reading head 28 for the rotational speed sensor 10. In the present embodiment, the read head 28 is connected to a wiring carrier in the form of a punched grid, for which the term leadframe is also used. Such a punched grid is for example from WO 2010/037 810 AI. The reading head 28 is shown in Fig. 3 in a punched-out of the stamped grid state. Therefore, of the stamped grid in Fig. 3, only one Bestückinsel 44, a first with the

Bestückinsel 44 integrally connected contact terminal 46 and a second of the Bestückinsel 44 separate contact terminal 48 to see.

On the Bestückinsel 44 of the sensor in the form of magnetostrictive element 35 and the Signalauswerteschal ^¬ device 40 is applied and contacted electrically, for example by soldering or gluing. The magnetostrictive element 35 and the signal evaluation circuit 40 are also connected to each other via a bonding wire 50, so that over the

Bestückinsel 44 and the bonding wire 50 between the magnetostrictive element 35 and the signal evaluation circuit 40, the Probesig- signal 39 can be transmitted. The signal evaluation circuit 40 is connected via a further bonding wire 50 to the second contact terminal 48. In this way, the data signal 42 can be output from the signal evaluation circuit 40 via the two contact terminals 46, 48. In this case, a filter capacitor 52 can be connected between the contact terminals 46, 48.

In order to protect the reading head 28, a protective layer 54 can be formed around the placement island 44 carrying the reading head 28 and a part of the contact terminals 46, 48, which can be seen in FIG. For brevity, reference is made to the relevant state of the art, such as, for example, WO 2010 / 037810A.

To protect the reading head 28 against moisture or other contaminants, the reading head 28 is housed in a housing 56 shown in Figs. 5-8.

For this purpose, the read head 28 first with a data signal 42nd to the controller leading data cable 58 electrically contacted.

Subsequently, the read head 28 is bent into a suitable shape for the end ^¬ application. Since it does not depend on this shape in the context of the invention, because this is arbitrary, reference will be made below, by way of example only, to the shape shown in Fig. 4 for the read head 28.

The finished bent reading head 28 is finally inserted into a tool 59 for prototyping the housing 56. This

In the context of the present embodiment, tool 59 is composed of a plurality of stationary tool parts, a first movable tool part 60, a second movable tool part 62 and a third movable tool part 64. In order to better represent the movable die parts 60 to 64 was dispensed ver ^¬ a representation of the stationary tool part.

The stationary tool part and the movable tool parts 60 to 64 together form a box with a mold space 66, in which the read head 28 and a portion of the data cable 58 are taken on ^¬ . The mold space 66 is dense except for not shown, through the box leading inlet openings for feeding shown in Fig. 5 to 7 shown material 68, 70 for molding the housing 56, wherein the movable tool parts 60 to 64 relative to the fixed tool part movable are arranged so as to form a movable wall for the mold space 66 and thus can change the shape space 66 in size.

The movable tool parts 60 to 64 can be designed as desired. In the context of the present embodiment, the movable tool parts 60 to 64 movable sliding blocks, which are recorded in the stationary tool part.

Hereinafter, the formation of the housing 56 by filling a material in the mold space 66 in the context of an injection molding process will be described in more detail. For this purpose, first, as shown in Fig. 5, a first material ^¬ 68 stuffed into the mold space 66 by injection molding. The filling of the first material 68 takes place, as already mentioned, via inlet openings, not further shown, into the shaping space 66.

After the mold space 66 is filled with the first material 68 in the state of the movable tool parts 60 to 64 shown in FIGS. 4 and 5, the movable tool parts 60 to 64 are displaced as shown in FIG. This is conveniently carried out in a ^¬ at least partially cured state of the first material 68, so that the partially cured case can be held by the not shown stationary tool part. By moving the movable tool parts 60 to 64 of the mold space 66 is increased in the region of the read head 28.

The second material 70 is then injected into this newly formed region of the molding space 66, as shown in FIG. 7. In this way, an absolutely sealed housing 56 is created in the region of the read head 28, but at the same time the

magnetostrictive element 35 within the housing 56 is highly ^¬ precisely positioned.

The finished encased read head 28 is finally shown in Fig. 8.

Claims

claims

A tool (59) for prototyping a housing (56) for a sensor (28) adapted to detect a physical field (33) dependent on a quantity (12) to be measured via a sensor (35) and an electrical sensor Output from ^¬ output signal (42) based on the detected physical field (33), comprising

a mold space (66) for receiving a housing (56) forming material (68) and the sensor (35), and a box with the forming space (66) bounding wall, wherein at least a part (60 to 64) of the mold space (66) limiting wall is slidably mounted.

2. Tool (59) according to claim 1, wherein the displaceable part (60 to 64) of the wall is designed as a slide which is movably mounted relative to the remaining part of the box.

3. Tool (59) according to claim 2, wherein the slide is a lissenstein.

4. Tool (59) according to any one of the preceding claims, wherein the mold space (66) is adapted to support the sensor (35) prior to filling the housing (56) forming material (68) on the displaceable wall (60 to 64).

5. A method of using a tool (59) according to any one of the preceding claims for making the housing (56), comprising:

- Inserting the sensor (35) in the mold space (66), filling the material (68) in the mold space (66), moving the movable part (60 to 64) of the wall, and filling a further material (70) in the

Mold space (66) during or after moving the movable part (60 to 64) of the wall.

6. The method of claim 5, wherein the material (68) and the further material (70) are the same.

7. The method of claim 5 or 6, wherein the material (68) is a thermoplastic.

8. The method according to any one of the preceding claims 5 to 7, wherein the further material (70) when filling in the mold space (66) has a heat energy with which the previously filled material (68) is at least partially melted.

9. sensor (10) for detecting a dependent of a size to be measured (12) physical field (33) via a sensor (35) and for outputting an electrical output signal (42) based on the detected physical field (33) comprising A housing (56) made by a method according to any one of the preceding claims.