U.S. patent application number 15/039584 was filed with the patent office on 2017-06-15 for method for producing a sensor.
The applicant listed for this patent is Continental Teves AG & CO. oHG. Invention is credited to Manfred Goll, Jakob Schillinger, Ulrich Schrader, Gerhard Sticksel.
Application Number | 20170165885 15/039584 |
Document ID | / |
Family ID | 53045669 |
Filed Date | 2017-06-15 |
United States Patent
Application |
20170165885 |
Kind Code |
A1 |
Goll; Manfred ; et
al. |
June 15, 2017 |
METHOD FOR PRODUCING A SENSOR
Abstract
A method for producing a sensor which is equipped to detect a
physical field as a function of a dimension to be measured using a
measuring sensor and to emit an electrical output signal based on
the detected physical field via a data cable, including:--placing
the measuring sensor and the data cable on a mould defining the
position of the measuring sensor and the data cable,--Coating the
measuring sensor and the data cable positioned in the mould with a
first material,--Removing the measuring sensor and data cable
coated with the first material from the mould, and--Coating the
measuring sensor and data cable removed from the mould and coated
with the first material with a second material.
Inventors: |
Goll; Manfred; (Glauburg,
DE) ; Schrader; Ulrich; (Wollstadt, DE) ;
Schillinger; Jakob; (Gaimersheim, DE) ; Sticksel;
Gerhard; (Gelnhausen-Haitz, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Continental Teves AG & CO. oHG |
Frankfurt |
|
DE |
|
|
Family ID: |
53045669 |
Appl. No.: |
15/039584 |
Filed: |
October 8, 2014 |
PCT Filed: |
October 8, 2014 |
PCT NO: |
PCT/EP2014/071588 |
371 Date: |
May 26, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 45/14065 20130101;
B29C 2045/14139 20130101; B29C 45/14221 20130101; B29C 45/14639
20130101; B29L 2031/34 20130101; B29C 45/14819 20130101; G01D
11/245 20130101; B29L 2031/3481 20130101; B29K 2995/0069 20130101;
B29C 45/16 20130101; B29C 45/1671 20130101; B29C 2045/14131
20130101; B29C 2045/14122 20130101 |
International
Class: |
B29C 45/14 20060101
B29C045/14; B29C 45/16 20060101 B29C045/16 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2013 |
DE |
10 2013 224 464.9 |
May 6, 2014 |
DE |
10 2014 208 425.3 |
Claims
1. A method for producing a sensor which is configured to detect a
physical field, dependent on a variable to be measured, by a
measuring sensor, and to output an electrical output signal on the
basis of the detected physical field via a data cable, the method
comprising: placing the measuring sensor and the data cable in a
mold which defines a position of the measuring sensor and of the
data cable, encapsulating the measuring sensor and data cable
positioned in the mold with a first material, removing the
measuring sensor and data cable encapsulated with the first
material from the mold, and encapsulating the measuring sensor and
data cable encapsulated with the first material and removed from
the mold with a second material.
2. The method as claimed in claim 1, wherein the mold comprises a
positioning element with which the measuring sensor is
positioned.
3. The method as claimed in claim 1, wherein the mold comprises a
shaping element on which the measuring sensor is shaped before or
during the encapsulation with the first material.
4. The method as claimed in claim 3, wherein the shaping element is
a bending element.
5. The method as claimed in claim 1, further comprising molding a
positively locking element in the first material during the
encapsulation of the measuring sensor and data cable, positioned in
the mold, with the first material.
6. The method as claimed in claim 5, further comprising molding a
sealing contour around the positively locking element during the
encapsulation of the measuring sensor and data cable, positioned in
the mold, with a first material.
7. The method as claimed in claim 5, further comprising inserting a
securing element into the positively locking element, to which
securing element the measuring sensor, encapsulated with the first
material, and the data cable can be secured after the encapsulation
with the first material.
8. The method as claimed in claim 1, wherein the measuring sensor,
encapsulated with the first material and removed from the mold, and
the data cable are encapsulated with the second material in a
non-cured state of the first material.
9. The method as claimed in claim 1, her comprising forming a
sealing contour which, when viewed in the direction of the data
cable, runs around the first material, on the first material on a
side of the data cable lying opposite the measuring sensor.
10. A sensor for detecting a physical field, dependent on a
variable to be measured, by a measuring sensor and for outputting
an electrical output signal on the basis of the detected physical
field of a data cable, which sensor is produced by a method as
claimed in claim 1.
11. A mold for use in a method as claimed in claim 1, comprising: a
first mold part, and a second mold part which is configure, for
placement on the first mold part, wherein the two mold parts form,
when they are placed one on the other, a casting cavity in which
the data cable, the measuring sensor and the first material can be
at least partially accommodated, and wherein a bending die is
formed on the first mold part, and a recess is formed on the second
mold part, for accommodating the bending die, by which bending die
and recess the measuring sensor shaped when the second mold part is
placed on the first mold part.
12. The method as claimed in claim 2, wherein the mold comprises a
shaping element on which the measuring sensor is shaped before or
during the encapsulation with the first material.
13. The method as claimed in claim 6, further comprising inserting
a securing element into the positively locking element, to which
securing element the measuring sensor, encapsulated with the first
material, and the data cable can be secured after the encapsulation
with the first material.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the U.S. National Phase Application of
PCT International Application No. PCT/EP2014/071588, filed Oct. 8,
2014, which claims priority to German Patent Application No. 10
2013 224 464.9, filed Nov. 28, 2013 and German Patent Application
No. 10 2014 208 425.3, filed May 6, 2014, the contents of such
applications being incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The invention relates to a method for producing a sensor and
to the sensor produced by the method.
BACKGROUND OF THE INVENTION
[0003] WO 2010/037 810 A1, which is incorporated by reference
discloses a sensor for outputting an electrical signal which is
dependent on a physical variable which is detected by means of a
physical field on the basis of a measuring sensor.
SUMMARY OF THE INVENTION
[0004] An aspect of the invention aims to improve the known
sensor.
[0005] According to one aspect of the invention, a method for
producing a sensor which is configured to detect a physical field,
dependent on a variable to be measured, by means of a measuring
sensor, and to output an electrical output signal on the basis of
the detected physical field via a data cable, comprises the steps:
[0006] placing the measuring sensor and the data cable in a mold
which defines the position of the measuring sensor and of the data
cable, [0007] encapsulating the measuring sensor and data cable
positioned in the mold with a first material, [0008] removing the
measuring sensor and data cable encapsulated with the first
material from the mold, and [0009] encapsulating the measuring
sensor and data cable encapsulated with the first material and
removed from the mold with a second material.
[0010] The specified method is based on the idea that the measuring
sensor and the data cable have to be enclosed completely by at
least one of the two materials for both elements to be protected
from moisture and other influences which bring about weathering. In
order to enclose the two elements, they can be placed in a mold,
which is then, for example, filled with the first material by
injection molding. However, the problem basically arises here that
part of the elements always rest on the edge of the mold, and
therefore no complete seal is possible with the material at these
locations because the elements cannot be encapsulated with the
material at these locations.
[0011] Although, for example, by using a securing mechanism the
measuring sensor can be secured in such a way that all the elements
can be encapsulated completely with the material, the measuring
sensor must be positioned in this securing mechanism, which, in
particular owing to the rigidity of the cable, is only possible to
a limited degree within sufficient tolerances. In addition, the use
of the measuring sensor in the securing mechanism requires
additional fabrication steps, and also the securing mechanism
cannot be completely encapsulated, as a result of which gaps remain
through which the abovementioned moisture can penetrate and reach
the measuring sensor and/or the data cable.
[0012] Within the scope of the specified method, a different
approach is therefore adopted. Here, the measuring sensor with the
data cable is encapsulated with the first material in a first step.
In the process, no consideration is given to whether the measuring
sensor and/or the data cable are partially exposed and have
locations which are not encapsulated by the first material.
Instead, the measuring sensor and the data cable can be positioned
highly precisely when they are encapsulated with the first material
by injection molding. Only subsequently, during the encapsulation
with the second material by injection molding, are the measuring
sensor and the data cable encapsulated in such a way that no
exposed locations which are subjected to moisture or other
influences which produce weathering remain on these elements. In
this way, a sensor can be produced with a highly precisely
positioned measuring sensor which is resistant to the influences of
the weather such as moisture.
[0013] In one development of the specified method, the mold
comprises a positioning element in which the measuring sensor is
positioned. This positioning element can be made available in any
desired way like, for example, the abovementioned securing
mechanism. The highly precise position of the measuring sensor can
be implemented with a simple means by virtue of the positioning
element.
[0014] In an additional development of the specified method, the
mold comprises a shaping element on which the measuring sensor is
shaped before or during the encapsulation with the first material.
With the shaping element, the data cable and the measuring sensor
can be placed in the mold which they require for the final
application, during the encapsulation of the first material. In
this way, the clocking times while the specified method is carried
out can be reduced.
[0015] In a particular development of the specified method, the
shaping element is a bending element. With such a bending element,
the measuring sensor can be bent into a position in which it can
detect the abovementioned physical field particularly
favorably.
[0016] In another development, the specified method comprises the
step of molding a positively locking element in the first material
during the encapsulation of the measuring sensor and data cable,
positioned in the mold, with a first material. This positively
locking element can be used to connect the measuring sensor and the
data cable, which are surrounded by the first material, to further
elements.
[0017] In one preferred development, the specified method comprises
the step of molding a sealing contour around the positively locking
element during the encapsulation of the measuring sensor and data
cable, positioned in the mold, with a first material. The
previously mentioned further element could form, after the
encapsulation with the second material, a gap between the further
element and the second material. In this context, there is
basically the risk of the abovementioned moisture being able to
penetrate via this gap. As a result of the sealing element, this
risk of penetration can be reduced, if not entirely avoided.
[0018] In one particularly preferred development, the specified
method comprises the step of inserting a securing element into the
positively locking element, to which securing element the measuring
sensor, encapsulated with the first material, and the data cable
can be secured after the encapsulation with the first material. In
this way, the first material can be completely surrounded by the
second material without exposed locations remaining on the first
material, with the result that a high degree of leakproofness can
be achieved with the second material.
[0019] In a further development of the specified method, the
measuring sensor, encapsulated with the first material and removed
from the mold, and the data cable are encapsulated with a second
material in a non-cured state of the first material. In this way,
the first material and the second material can be connected to one
another during the encapsulation with the second material, with the
result that gaps between the first material and the second material
are closed.
[0020] In yet another development, the specified method comprises
the step of forming a sealing contour which, when viewed in the
direction of the data cable, runs around the first material and is
arranged on the first material on a side of the data cable lying
opposite the measuring sensor. This sealing element makes it
possible to avoid a situation in which moisture penetrates the
produced sensor at a connection point for the data cable.
[0021] According to a further aspect of the invention, a sensor for
detecting a physical field, dependent on a variable to be measured,
by means of a measuring sensor and for outputting an electrical
output signal on the basis of the detected physical field by means
of a data cable is produced by means of a specified method.
[0022] According to a further aspect of the invention, a mold for
use in one of the specified methods comprises a first mold part,
and a second mold part which can be placed on the first mold part,
wherein the two mold parts form, in the state in which they are
placed one on the other, a casting cavity in which the data cable,
the measuring sensor and the first material can be at least
partially accommodated, and wherein a bending die is formed on the
first mold part, and a recess is formed on the second mold part,
for accommodating the bending die, by means of which bending die
and recess the measuring sensor can be shaped when the second mold
part is placed on the first mold part.
[0023] The specified mold can be extended with the positioning aid
specified above as well as the abovementioned sealing mold
regions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The properties, features and advantages of this invention
which are described above and the way in which they are achieved
become clearer and more easily understandable in conjunction with
the following description of the exemplary embodiments which are
explained in more detail in conjunction with the drawings,
wherein:
[0025] FIG. 1 shows a schematic view of a vehicle with a vehicle
dynamics control system,
[0026] FIG. 2 shows a schematic view of a rotation speed sensor in
the vehicle in FIG. 1,
[0027] FIG. 3 shows a schematic view of a method sequence for
producing a part of the rotational speed sensor in FIG. 2,
[0028] FIG. 4 shows an illustration of a detail of the schematic
view in FIG. 3,
[0029] FIG. 5 shows an illustration of a detail of the schematic
view in FIG. 4, and
[0030] FIG. 6 shows a schematic view of an alternative method
sequence for producing a part of the rotational speed sensor in
FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] In the figures, identical technical elements are provided
with identical reference symbols and are described only once.
[0032] Reference is made to FIG. 1 which shows a schematic view of
a vehicle 2 with a vehicle dynamics control system which is known
per se. Details on this vehicle dynamics control system can be
found, for example, in DE 10 2011 080 789 Al, which is incorporated
by reference.
[0033] The vehicle 2 comprises a chassis 4 and four wheels 6. Each
wheel 6 can be slowed down with respect to the chassis 4 by means
of a brake 8 which is attached in a positionally fixed fashion to
the chassis 4, in order to slow down the movement of the vehicle 2
on a road (not illustrated further).
[0034] In this context, it is possible that, in a manner known to a
person skilled in the art, the wheels 6 of the vehicle 2 lose their
grip and the vehicle 2 is moved away even from a trajectory which
is predefined, for example, by means of a steering wheel (not shown
further), as a result of understeering or oversteering. This is
avoided by closed-loop control circuits which are known per se such
as ABS (anti-lock brake system) and ESP (electronic stability
program).
[0035] In the present embodiment, the vehicle 2 has for this
purpose rotational speed sensors 10 on the wheels 6 which detect
the rotational speed 12 of the wheels 6. In addition, the vehicle 2
has an inertial sensor 14 which detects movement dynamics data 16
of the vehicle 2 from which, for example, a pitch rate, a rolling
rate, a yaw rate, a lateral acceleration, a longitudinal
acceleration and/or a vertical acceleration can be output in a
manner known per se to a person skilled in the art.
[0036] On the basis of the detected rotational speeds 12 and
movement dynamics data 16, a controller 18 can determine, in a
manner known to a person skilled in the art, whether the vehicle 2
is slipping on the underlying surface or even deviating from the
abovementioned, predefined trajectory, and said controller 18 can
correspondingly react thereto with a controller output signal 20
which is known per se. The controller output signal 20 can then be
used by an actuating device 22 in order to drive, by means of
actuation signals 24, actuating elements such as the brakes 8 which
react to the slipping and the deviation from the predefined
trajectory in a manner known per se.
[0037] The present invention will now be explained in more detail
on the basis of the rotational speed sensor 10 shown in FIG. 1,
even if the present invention can be implemented in any desired
electronic devices and, in particular, in any desired sensors such
as magnetic field sensors, acceleration sensors, rotational speed
sensors, solid-borne sound sensors or temperature sensors.
[0038] Reference is made to FIG. 2 which shows a schematic view of
the rotational speed sensor 10 in the vehicle 2 in FIG. 1.
[0039] The rotational speed sensor 10 is embodied in the present
embodiment as an active rotational speed sensor 10, within the
scope of which an encoder disk 26, which is connected in a
rotationally fixed fashion to one of the wheels 6 and is composed
of a multiplicity of magnetic poles 28 outputs a magnetic field 30.
The magnetic field 30 penetrates a measuring sensor 34 which is
housed in a housing 32 and is connected via a signal-conditioning
circuit 36 to a data cable 38 via which the rotational speed 12 can
be transmitted to the controller 18. In this context, the measuring
sensor 34, the signal-conditioning circuit 36 and the data cable 38
can be connected to one another by means of wiring connections 40,
for example in the form of a leadframe.
[0040] Further background information on active rotational speed
sensors can be found, for example, in DE 101 46 949 A1, which is
incorporated by reference.
[0041] Reference is made to FIGS. 3 to 5 which show a schematic
view of a method sequence for the production of a part 42 of the
rotational speed sensor 10 in FIG. 2.
[0042] In this context, the part 42 of the rotational speed sensor
10 is illustrated in various fabrication stages 43 to 48, which are
not illustrated in a progressive sequence in terms of the execution
of the production method in FIGS. 3 to 5. For the sake of clarity,
identical elements within the individual fabrication stages are
provided with a reference symbol only once in FIGS. 3 to 5.
[0043] The method starts in the first fabrication stage 43 with the
measuring sensor 34, the signal-conditioning circuit 36 and the
data cable 38 being connected to one another via the wiring
connections 40. In this context, the wiring connections 40 have
positioning openings 49 between the signal-conditioning circuit 36
and the data cable 38.
[0044] Within the scope of the second fabrication stage 44, the
circuit composed of the measuring sensor 34 connected in this way,
the signal-conditioning circuit 36 and the data cable 38 are
accommodated in a lower mold part 50 of a first molding. Details on
how this circuit is inserted into the lower mold part and how the
lower mold part 50 is constructed will be explained below with
reference to the exploded illustration within the scope of the
third fabrication stage 45.
[0045] The lower mold part 50 comprises two receptacle openings 51
in which positioning elements in the form of positioning pins 52
can be inserted. The abovementioned positioning openings 49 are
fitted onto these positioning pins 52, as can be seen in the second
fabrication stage 44.
[0046] In addition, the lower mold part 50 comprises a bending die
53, on which the wiring connection 40 between the measuring sensor
34 and the evaluation circuit 36 is placed. The measuring sensor 34
is bent with respect to the evaluation circuit 36 by means of the
bending die 53 within the scope of the production method, as will
be explained in more detail later, with the result that the
measuring sensor 34 can be bent parallel to the encoder disk 26 for
optimum detection of the magnetic field 30. This bent state is
already illustrated within the scope of the second fabrication
stage 44. However, in the unbent state of the measuring sensor 34,
the circuit is inserted into the lower mold part 50.
[0047] The lower mold part 50 also has a holding mold region 54,
via which a holding mold 55, to be described later below, can be
formed on an intermediate housing 56 which is to be molded with the
first mold. More details on this are given at a later location. A
sealing mold region 57, with which a sealing mold 58 can be formed
around the holding mold 55, on the intermediate housing, is formed
around this holding mold region 54. A similar further sealing mold
region 57 can be formed on the cable-side end of the lower mold
part 50.
[0048] In the next, third fabrication step 44, an upper mold part
59, which is associated with the first mold, is arranged above the
lower mold part 50, said mold part 59 being illustrated in a
cut-away form in FIGS. 3 to 5. The upper mold part 59 has in a
similar way to the lower mold part 50, a holding mold region 54 and
two sealing mold regions 57, which are, however, not provided with
a reference symbol in FIGS. 3 to 5 for the sake of clarity. In
addition, the upper mold part 59 has a recess 60 in which the
bending die 53 can be accommodated.
[0049] This upper mold part 59 is then moved, within the scope of
the fourth and fifth fabrication stages 46, 47 as shown in FIG. 3,
against the lower mold part 50, with the result that the casting
cavity between the two mold parts 50, 59, which casting cavity
comprises, inter alia, the holding mold region 54 and the sealing
mold regions 57 as well as a region which molds the intermediate
housing 56 and is not provided with further references, is closed.
Within the scope of this closing movement, the wiring connections
40 which are placed on the bending die 53 are bent, with the result
that the measuring sensor 34 is bent into the position described
above, in which it can be oriented parallel to the encoder wheel
26.
[0050] In the now closed casting cavity, a first encapsulation
material, which molds the intermediate housing 56, is now input by
pouring or injection molding. After initial curing of this first
encapsulation material, the two mold parts 50, 59 are removed
within the scope of the sixth fabrication stage 48 and inserted
into one of the two holding molds 55 which are formed (above or
below the intermediate housing 56), or a holding pin 61, which is
embodied as a holding element, is inserted into both holding molds
55. In this context, the intermediate housing 56 can also be held
in a stable way in a rear part 66 of the lower mold part 50.
[0051] As can be seen within the scope of the sixth fabrication
stage 48, parts of the abovementioned circuit, such as, for
example, the cable 39, are still exposed on the intermediate
housing 56. In order to close these regions, a terminating housing
62 is applied by injection molding to the intermediate housing 56
which has not yet completely cured, said terminating housing 62
completely closing off these exposed regions. As a result of the
fact that the terminating housing 62 is applied by injection
molding to the intermediate housing 56 in a state of said
intermediate housing 56 in which it is not completely cured, the
terminating housing and the intermediate housing can be connected
to one another better.
[0052] As a result, a rotational speed sensor 10 in which the
measuring sensor 34 is enclosed in a sealed fashion and therefore
protected against the ingress of moisture is provided.
[0053] Reference is made to FIG. 6 which shows a schematic view of
an alternative method sequence for producing a part of the
rotational speed sensor in FIG. 2.
[0054] Within the scope of this method sequence, the data cable 38
is not connected directly to the rotational speed sensor 10 but via
a plug 63. In this context, the plug 63 can be cast together with
the intermediate housing 56.
[0055] In this context, the measuring sensor 34 and the
signal-conditioning circuit 36 are connected to a leadframe 64 by
means of the wiring connection 40. The leadframe 64 can be embodied
here as meterware, wherein an individual leadframe section can be
cut out, for example with a punching element 65, before the molding
of the intermediate housing 56. Otherwise, the production can take
place in the same way as in FIGS. 3 to 5.
* * * * *