I
b I - , SPEED SENSOR FOR A GEAR MECHANISM
The present invention relates to a speed sensor for measuring the peripheral speed of a gear
wheel in a gear mechanism, in particular a double clutch gear mechanism, and to a gear
mechanism that contains this speed sensor.
Figure 1 shows an arrangement for measuring the peripheral speed of a gear wheel in a gear
mechanism with a known speed sensor. In an arrangement for measuring the peripheral speed
of a. gear wheel the speed sensor is fixed to the gear mechanism with the aid of a connection
flange such that it is located a specific distance away from the teeth of the gear wheel that are
passing it. In the arrangement shown in Figure 1, ,the face surface 107 of the speed sensor 100
is opposite the teeth of the gear wheel 130 that are passing it. A Hall sensor 102 is provided on
the face surface 107 of the speed sensor 100: This Hall sensor recognises a changing magnetic
field when the teeth of the gear wheel 130 pass the face surface 107 and forms an electric
signal corresponding to the changing magnetic field from which the peripheral speed of the
gear wheel is determined. In the arrangement according to. Figure 1 this electric signal i s
interfered with by vibrations which are generated by the motor driving the gear mechanism and
are input by the connection flange 107 fastened onto the gear mechanism. The lower the .
resonance frequency of the speed sensor 100, the greater the input.
In the speed sensor 100 the Hall sensor 102 i s fixed with respect to the housing'101 and the
connection flange 105 with a casting compound 103. The use of casting compound to fix the
magnetic sensor makes it difficult to produce the speed sensor. For example, one must ensure
that the magnetic sensor is not damaged during application and/or hardening of the casting
compound. In addition, the mass of the speed sensor 100 is increased by the casting compound
103, and this leads to lowering of i t s resonance frequency. Due to the low resonance frequency
the speed sensor 100 i s susceptible to interference from vibrations which are,generated by the
motor driving the gear mechanism.
It is therefore an object of the present invention to provide a speed sensor for a gear
mechanism which is easy to produce and is not susceptible to interference from vibrations
which are generated by the motor driving the gear mechanism.
This object is achieved according to the features of Claim 1. ~dvantageous further
developments of the present invention are the subject matter of the dependent claims.
The present invention is based on the idea of replacing the casting compound for fixing the
magnetic sensor with a holding apparatus made of thermoplastic and hot-caulking the magnetic
sensor to the holding apparatus. In this way production of the speed sensor is substantially
simplified and i t s mass.is clearly reduced. Due to the reduced mass, the speed sensor of the
present invention i s less susceptible to interference from vibrations which are generated by the
motor driving the gear mechanism.
For better understanding of the present invention the latter i s described in more detail by
means of the exemplary embodiments shown in the following figures. Here identical parts are
provided with the same reference numbers and the same component designations.
Furthermore, some features or combinations of features from the various embodiments shown
and described can constitute independent inventive solutions or solutions according to the
invention in their own right. These show as follows:
Fig. 1 an arrangement for measuring the peripheral speed of a gear wheel in a gear
, mechanism with a known speed sensor;
( , I , Fig. 2a a perspective illustration of the speed sensor according to the present invention and
1: I the inside of the lower end of the speed sensor;
I 1.
Fig. 2b an enlarged view of the inside of the lower end of the speed sensor;
Fig. 3 an exploded illustration of the speed sensor according to the present invention;
5 Fig. 4 an illustration (top view) of the carrier and of the magnetic sensor fixed onto it;
Fig. 5 a top view of the face surface of the holding apparatus;
Fig. 6 the interaction between the holding apparatus and the inside of the housing on the
lower end of the speed sensor according to the present invention;
Fis. 7 stress-strain diagrams for different slot lengths of the slots provided on the springs;
10 Fig. 8 an arrangement for measuring the peripheral speed of a gear wheelin a gear
mechanism with a speed sensor according to the present invention.
The speed sensor of the present invention i s primarily provided to. determine the peripheral
speed of a gear wheel in a gear mechanism, in particular a double clutch gear mechanism.
Therefore, i t s structure is -adapted specifically for this application. In particular, the structure
15 must guarantee'that the speed sensor can be fastened to a point on the gear mechanism
housing which allows i t s sensitivelsensory point to be brought close to the teeth of the gear
wheel being examined. In addition, the structure of the speed. sensor must suarantee damping
of the vibrations which are generated by the motor driving the gear mechanism and are input
into the speed sensor via the gear mechanism housing.
20 Figure 2a shows a perspective illustration of the speed sensor according to the present
invention and the inside of the lower end of the speed sensor. The speed sensor 200 has a
carrier 203 and a housing 201 which surrounds the lower part of the carrier 203. Provided on
the carrier 203 is a flangelcover 301 and on the upper edge of the housing 201 a collar 302
which interact such that the housing 201 ends/covers the lower part of the carrier 203.
25 Preferably, the edge regions of the flange 301 and of the collar 302 are laser-welded. The
upper part of the carrier 203, i.e. the part of the carrier that is disposed above the flange 301
and is not coveredlsurrounded by the housing 201, has electric connections 205. Preferably,
these are provided on the upper end of the carrier 203. The lower part of the carrier 203, i.e.
the part of the carrier that is disposed beneath the flange 301 and i s covered by the housing
30 201, has a holdfng apparatus 204 on the lower end of which a magnetic sensor 202 is provided.
The magnetic sensor 202, which is for example a Hall sensor or a magneto-resistive sensor
(GMR, AMR or CMR sensor), has electric lines which are connected electrically to the electric
connections 205.
According to the invention the holding apparatus 204 i s formed from a thermoplastic.
35 Preferably, not only the holding apparatus 204, but the entire carrier 203, is formed from a
thermoplastic. This improves not 'only the stability of the carrier 203, but also simplifies i t s
production. The thermoplastic is for example thermoplastic PA 66 with a glass fibre (GF)
portion of 15% to 30%. In particular, thermoplastic PA 66 with a glass fibre portion of 30% has a
Young's modulus, a tensile strength and an elongation with are suited optimally to the material
40 demands made of the carrier 203.
Figure 2b shows an enlarged view of the inside of the lower end of the speed sensor 200 already
shown in Figure 2a. By means of Figure 2b the structure of the holding apparatus 204, the
stabilisationlsuspension of the holding apparatus 204 within the housing 201 and the fixing of
the magnetic sensor 202 to the holding apparatus 204 is described.
,Figure 2b shows that the holding apparatus 204 has a face surface on its lower end, and that
the sensor head 206 of the magnetic sensor 202 is provided on the face surface, between the
latter and the inside of the housing 201. A detailed description of the face surface and of the
qrrangement of the sensor head 206 on the face surface will be given later by means of Figures
5 and 6. In addition, the lower end of the holding apparatus 204 has a side projection 208 and a
side projection 209 diametrically opposed to the latter. Both projections 208 and 209 are in
contact with the inside of the housing 201 at two opposing points. According to the invention
the projections 208 and 209 have at the points where they touch the inside of the housing 201
an excess length with respect to the inside of the housing 201 so that the projections 208 and
209 are pushed from the inside of the housing 201 towards the sensor head 206 when the
holding apparatus 204 is located within the housing 201. The electric lines 220 of the magnetic
sensor 202 are bent by 90' with respect to the sensor head 206 and are guided towards the
upper end of the holding apparatus 204 between fixing elements which are provided on the
holding apparatus 204. In addition, the two lines 220 are cross-connected by the capacitor 221.
The latter is embedded in a fixing depression provided on the holding apparatus 204 and also
contributes to the fixing of the electric Lines 220 onto the holding apparatus 204.
According to the invention the magnetic sensor 202 is fixed/stabilised on the holding apparatus
204 by caulking, preferably hot-caulking. In the exemplary embodiment of the present
invention shown in Figures 2a and Zb, the magnetic sensor 202 is hot-caulked to the holding
apparatus 204 between the line sections 220 which are located between the sensor head 206
and the capacitor 221. This point is given reference number 222 in Figure Zb.
The fixinglstabilising of the magnetic sensor 202 on the holding apparatus 204 is improved if
the two electric lines 220 are laser-welded to the holding apparatus 204, preferably if the ends
of the electric lines 220 further away from the sensor head 206 are laser-welded to the holding
apparatus 204,
According to the invention the exemplary embodiment shown in Figures 2a and 2b has two
additional projections 403 and 404 between the upper and the lower end of the holding
apparatus 204. The projections 403 and 404 are arranged diametrically opposed and touch the
inside of the housing 201 at two opposing spots with a precise fit. In this way the holding
apparatus 204 is additionally stabilised within the housing 201 and vibration of the holding
apparatus 204 within the housing 201 is prevented. Preferably, the points at which the
projection 208 and the projection 403 tpuch the inside of the housing 201 are located on a first
straight line that i s parallel to the height direction of the holding apparatus 204; and the points
at which the projection 209 and the projection 404 touch the inside of the housing 201 are
located on, a second straight line which i s also parallel to the height direction of the holding
apparatus 204.
Figure 3 shows an exploded illustration of the speed sensor 200 according to the present
invention. By means of the latter the features of the carrier 203 and of the housing 201, which
can not be seen by means of Figures 2a and Zb, are described in more detail. In particular, the
flangelcover 301 of the carrier 203 and the structure of the hotding apparatus 204, which
adjoins the lower side of the flange 301, can be seen better in Figure 3. Apart from the
magnetic sensor 202, a magnet 217 is also provided on the holding apparatus 2b4 for
magnetically preloading the magnetic sensor 202. One can also see the projections 208 and 403
facing the inside (the inner lateral surface) of the housing 201 which are disposed on an outside
of the holding apparatus 204. The projections 209 and 404 from Figure 2b can not be seen in
Figure 3, but are disposed on the outside of the holding apparatus 204 which lies opposite the
outside with the projections 208 and 403. The upper part of the holding apparatus 204, beneath
the flange 301, is shaped such that it touches the inside of the housing 201 with'form-locking
I
b , and so stabilises the holding apparatus 204 on the housing 201 at the side when the holding
i I apparatus 204 is inserted into the housing 201.
t
The housing 201 is, for example, cylindrical in shape. Provided on the inner lateral sur'face of
the housing 201 are depressions which interact with the side projections 208, 209; 403, 404 and
5 the projection 523 shown in Figure 5. The collar/rim 302, which is provided on the upper part
of the housing 21, interacts with the cover 310 of the carrier 203 such that the holding
apparatus 204 i s completely covered by the housing 201. The collar 302 has a fastening
apparatus 303 by means of which the speed sensor 200 is fixed to a gear box. An O-ring 230 can
be provided on the outer circumference of the lower part of the housing 201.
10 Figure 4 shows an illustration of the carrier 203 shown in Figures 1 to 3. Here the side of the
carrier 203 on which the electric connections 205 are provided is shown. The. carrier 203 has a
face surface 207 which is provided on the end of the holding apparatus 204 lying opposite the
flange 301. The sensor head 206, 'which has an upper and a lower surface, i s disposed
approximately centraUy on the face surface 207. The lower surface is in contact with the face
15 surface 207 here, and the upper surface is free. The electric lines 220 of the magnetic sensor
202, which are bent towards'the lower surface of the sensor head 206, are guided towards the
upper end of the holding apparatus 204 parallel to the longitudinal axis 405 of the carrier 307.
According to the invention, the magnetic sensor 202 is fixed onto the holding apparatus 204 by
hot-caulking at point 222. Preferably, the electric lines 220 are also fixed onto the holding
20 apparatus 204 by welding.
Figure 5 shows a top view of the lower end of the holding apparatus 204, i.e. the face surface
207. There is provided on the lower end of the holding apparatus 204, in the face surface 207, a
recesslcut-out 210 for receiving the sensor head 206 of the magnetic sensor 202. This recess i s
arranged symmetrically in relation to the centre line 520 of the .face surface 207 and is
25 substantially cuboid in form. The recess 210 has two side walls 211 and 212 parallel to the
centre line 520 and a side wall 521 perpendicular to the centre line 520. The length of the side
walls 21 1, 212 and 521 has dimensions such that the sensor head 206 is fully accommodated by
the recess 210. Preferably, the sensor head 206 i s positioned centrally in relation to the face
surface. The depth of the recess 210 corresponds substantially to the height of the sensor head
30 206. On the side of the recess 210 lying opposite the side wall 521 the two side walls 21 1 and
212 can have a slight outwards slant in order to facilitate threading/inserti,on. of the sensor
head 206 into the recess'210. Furthermore, the projections 208 and 209 (already shown in
Figures 2 and 4) and a projection 523 are provided on the lower end of the holding apparatus
204. The last of these projections serves to align/orientate.the holding apparatus 204 within
35 the housing 201.
According to the invention the lower end of the holding apparatus 204 i s formed from a
thermoplastic, preferably from thermoplastic PA 66 with a glass fibre portion of 15% to 30%.
Since thermoplastics have a certain degree of elasticity, the part 213 of the lower end of the
holding apparatus 204 located between the projection 208 and the side wall 211 acts like a
40' spring. he spring 213 is elastic to such an extent that it allows (elastic) displacement of the
' .side wall 21 1 towards the centre line 520 if a force 525 that is directed from the outside to the
centre line 520 is acting on the projection 208. The displacement of the side wall 211
disappears i f the force 525 is no longer acting. Likewise, the part 214 of the lower end of the
holding apparatus 204 located between the projection 209 and the side wall 212,acts like a
45 spring. The spring 214 is elastic to such an extent that it allows (elastic) displacement of the
side wall 212 to the centre line 520 if a force 526 directed from the outside to the centre line
520 is acting on the projection 209. The displacement of the side wall 212 disappears if the
force 526 is no longer acting.
, According to the invention the flexibility (or rigidity, which is defined as the inverse value of
flexibility) of the spring 21 3 is set to a predetermined value by means of a slotlnotch 215 in the
length LO. The slot 21 5 is provided here on the lower end of the holding apparatus 204 between
the side wall 21 1 and the outside of the holding apparatus 204 containing the projection 208,
approximately parallel to the centre line 520. The flexibility (or rigidity) of the spring 214 is set
to a predetermined value by means of a slotlnotcti 216. Here the slot 216 is provided on the
lower end of the holding apparatus 204 between the side wall 212 and the outside of the
holding apparatus 204 containing the projection 209 approximately parallel to the centre line
520. In addition, in Figure 5 the slots 215 and 216 are provided on the face surface 207 between
the side projections 208 and 209 and the outside' of the holding apparatus 204 lying opposite
the projection 523.
By means of Figure 7 it is explained how the flexibility of one of the two springs 213 and 214
depends on the length of the respective slot. Figure 7 shows stress-strain diagrams of a spring
for different lengths of the slot. Here the ordinate specifies the forcelstress acting on the
spring, and the abscissa specifies the displacement of the spring towards the centre line. The
curve 701 corresponds to a spring that has a slot of length LO; the curve 702 corresponds to a
spring with a slot the length of which is smaller than LO; and the curve 703 corresponds to a
spring with a slot the length of which is greater than LO. Therefore, the flexibility of the spring
increases as the slot length becomes longer. '
Figure 7 illustrates the interaction between the holding apparatus 204 and the inside of the
housing 201, specifically in a sectional plane that contains the face plane 207 of the holding
apparatus 204. Figure 7 shows that the inside of the housing 201 has depressions 'regular
distances apart from one another and that the projections of the holding apparatus 204 engage
in the depressions. The depressions on the inside.of the housing 201 are elongate and straight in
form and extend along the height direction of the housing 201, from the bottom up to a height
which makes it possible to introduce the holding apparatus 204 into the housing 201, the
projections 208, 209 and 523 respectively engaging in a depression cprresponding to them. In
Figure 6 the projection 208 engages in the depression 601, the projection 209 in the depression
602, and the projection 523 in the depression 603. By turning the holding apparatus 204 about
45' the projection 208 ,would engage.in. the depression adjacent to the depression 601, the
projection 209 would engage in the depression adjacent to the depression 602, and the.
projection 523 would engage in the depression adjacent to the depression 603. Since the
projection 523 only serves to align the holding apparatus 204 within the housing 201, this
projection is not essential to the present invention.
The holding apparatus 204 can have different discrete positions within the housing 201. In each
of these positions each of the projections 208 and 209 has an excess length with respect to the
inside of the housing 202, specifically with respect to the depression in which it engages. The
depressions are preferably all of the same depth. Since each of the projections 208 and 209 has
an excess length with respect to the inside of the housing 201, upon introducing the holding
apparatus 204 into the housing 201, the projections 208 and 209 are pushed inwards through
the inner wall of the housing 201 towards the centre line 520. The side walls 21 1 and 212 of the
recess/cut-out 210 are moved towards the centre line 520 by the pressure of the inner wall of
the housing 201 on the projections 208 and 209, and the spring 213 acting between the side
wall 211 and the projection 208 and the spring 214 acting between the side wall 212 and the
projection 209 are tensioned.
According to the invention the flexibility of the springs 213 and 214 i s set such that the springs
213 and 214 damp, and preferably prevent, the propagation of vibrations of the housing 201
towards the senior head 206. Vibrations of the housing 201 can be instigated, for example, by
the motor driving the gear mechanism. Here the vibrations are input by the fixing device 303 by
#'% A . DEQHH 13'-02-201.5 1 7 ' . L S
, means of which the speed sensor is fixed onto the gear mechanism. The vibrations of the
housing 201 brought about in this way are essentially a to and fro movement of the lower end
of the housing 201 transversely to i t s longitudinal direction. If the connection between the
lower end of the housing 201 and the lower end of the holding apparatus 204 were rigid, this
movement would be completely transferred onto the sensor head (magnetically sensitive part)
of the magnetic sensor, and would lead to a signal component in the output signal of the
magnetic sensor 202 which would be superposed over the signal corresponding to the peripheral
speed of the gear wheel as an interference signal. The springs 213 and 214 prevent complete
transfer of the to and fro movement of the housing 201 onto the magnetic sensor 202 so that
the latter remains at rest with respect to the gear wheel, even when the housing 201 is
vibrating.
In the exemplary embodiment of the present invention shown in Figures 2 to 6, the inside of the
housing 201 exerts a pressure upon the springs 213 and 214 via the projections 208 and 209
arranged at the side. However, the present invention is not restricted to this exemplary
embodiment, bu't also covers exemplary embodiments in which any type of pressure points are
provided instead of the side projections 208 and 209, and for which there are provided on the
inside of the housing points that are in contact with the pressure points. For example, the
pressure point on the oljtside of the holding apparatus 204 can be made as a flat surface, and
the point on the inside of the housing 201, which touches the pressure point, can have a
projection towards the respective pressure point. In this case the spring would be formed by
the part which i s located between the pressure point and the side wall of the.recess.
The present invention is not restricted either to an exemplary embodiment with just two
springs, but also. covers exemplary embodiments in which the magnetically sensitive part
(sensor head) of the magnetic sensor is disposed at the lower end of the holding apparatus,
between a plurality of springs. In this case the flexibility of each spring i s to be chosen from the
plurality of springs such that the plurality of springs damp/prevent the propagation of
vibrations of the housing 201 towards the magnetically sensitive part 206 of the magnetic
sensor 202. For example, the' magnetically sensitive part 206 can be disposed/suspended
between three springs that are located at an angle of 120". In an exemplary embodiment with
three springs the outside of the holding apparatus would have three pressure
points/projections, and these touch the inside of the housing at three points. Here the inside of
the housing would exert pressure upon each of the three .pressure points'/projections and thus
tension each of the three springs.
Figure 8 shows an arrangement for measuring the peripheral speed of a gear wheel in a gear
mechanism with a speed sensor according to the present invention. The speed sensor 200 is
fixed to the gear mechanism with the aid of the fixing device 303 such that i t s face surface is a
specific distance away,from the teeth of the gear wheel 130. The magnetically sensitive part of
the magnetic sensor 202 (sensor head) provided on the face surface of the speed sensor 200
recognises a changing magnetic field if ttie teeth of the gear wheel 130 pass i t s face surface
and forms an electric signa1 corresponding to the changing magnetic field from which the
peripheral speed of the gear wheel 130 is determined. This electric signal has largely no
interference due to mechanical vibrations which are generated by the motor driving.the gear
mechanism because, on the one hand, the resonance frequency of the speed sensor 200 is well
over the frequency of the vibrations generated by' the motor, and on the other hand,
propagationlpassing on of the vibrations of the housing 201 to the sensor head i s prevented by
springs which are provided on the face surface of the holding apparatus 204. In.addition,
production of the speed sensor according to.the present invention i s simpler and cheaper than
that of the known speed sensor shown in Figure 1.
" I
a , List of reference signs:
C .
n
100 Known speed sensor
I
Reference number
101
102
Description
Housing
Hall sensor
103
I
107 I Face surface of the known speed sensor I
1
Casting compound
I
105 Connection flange
130 Gear wheel
200
201
202
203
Speed sensor
Housing
Magnetic sensor
Carrier
I
204
I
Holding apparatus
205
I
Electric connections .
206
I
Head of the magnetic sensor (sensor head)
207
I
I
21 0 I Recess in the holding apparatus
Face surface of the holding apparatus
208
209
1
Flrst project'ion on the holdlng apparatus
Second projection on the holding apparatus
I
21 1 First side wall of the recess
21 2 Second side wall of the recess
21 3 First spring
I
214
21 5
I
21 7 I Magnet
Second spring
Slot in the first spring .
I
21 6 Slot in the second spring
220 Electric lines of the magnetic sensor
221 Capacitor
222 I Caulking of the sensor in the holding apparatus I I
230 I O-ring
301 Flange
302 Collar
I
303
I
Fixing device
403
404
Third projection on the holding apparatus
Fourth projection on the holding apparatus
405 Main axis of the carrier
520
521
523
Centre line of the face surface
Third side wall of the recess
Fifth projection on the holding apparatus
I
525,526
601
Force
First point on the inside of the housing
602 Second point on the inside of the housing
I
603
701 .., 703
Depression/Groove on the inside of the housing
Stress-Strain diagram for different flexibility
(rigidity) values

I. .
Claims: I
?. A speed sensor for a gear mechanism, in particular a double clutch gear mechanism which
has:
5 a magnetic sensor (202);
a carrier (203) that has a holding apparatus (204) for the magnetic sensor (202) and a flange
(301) with electric connections (205) on the upper end of the holding apparatus, and
a housing (201) that surrounds the holding apparatus (204) for the magnetic sensor (202) and
has on i t s upper edge a coILar (302) that interacts with the flange (301) of the carrier (203),
10 characterised in that
the carrier (203) i s formed from a thermoplastic, and .
the magnetic sensor (202) i s hot-caulked to the holding apparatus (204).
2. The speed sensor according to Claim ?, characterised in that the magnetically sensitive part
(206) of the magnetic sensor (202) is disposed on the lower end of the holding apparatus (204)
15 between a plurality of springs, and
the flexibility of each spring is chosen from the plurality of springs such that the plurality of
springs damp, and preferably prevent, the propagation of vibrations of the housing (201) to the
magnetically sensitive part (206) of the magnetic sensor (202).
3, The speed sensor according to Claim 2, characterised in that the plurality of springs .includes
20 a first spring (21 3) and a second- spring (214) lying opposite the first spring.
4, The speed sensor according to Claim 3, characterised in that the lower end of the holding
apparatus (204) has a face surface (207),
a recess.(210) is provided in the face surface (207) for receiving the magnetic sensor (202),
the recess (210) has a first side wall (211) and a second side wall (212) lying opposite the first
25 side wall,
the magnetically sensitive part (206) of the magnetic sensor (202) is disposed in the recess
(210) between the first and the second side wall,
the lower end of the holding apparatus (204) has an outside facing the inside of the housing
(207 1,
30 a first pressure point is provided on the outside of the holding apparatus (204) opposite the first
side wall (211) of the recess (210),
the part of the lower end.of the holding apparatus located between the first pressure point and
the first side wall (21 1) forms the first spring (213),
there is provided on the inside of the housing (201) a first point (601) that is in contact with the
first pressure point,
the first pressure point is pushed towards the recess (210) if the first pressure'point touches the
first point (601) on the inside of the housing (201),
a second pressure point is provided on the outside of the holding apparatus (204) opposite the
second side wall (212) of the recess (210)) B
the part of the lower end of the holding apparatus located between the second pressure point
and the second side wall (212) forms the second spring (214))
a second point (602)) which is in contact with the second pressure point, is provided on the
inside of the housing (201 ), and
the second pressure point is pushed towards the recess (210) when the second pressure point
touches the second point (612) on the inside of the housing (201).
5. The speed sensor according to Claim 4, characterised in that the yutside of the holding
apparatus (204) has at the first pressure point a first projection (208)that has an excess length
with respect to the first point (601).on the inside of the housing (201), and/or
the outside of the holding apparatus (204) has at the second pressure point a second projection
(209) that has an excess length with respect to the second point (602) on the inside of the
housing (201 ).
6. The speed sensor according to-Claim 5, characterised in that the inside of the housing (201)
has ,at the first point (601) a first depression, and the first projection (208) engages in the first
depression, and/or
the inside of the housing (201) has a second depression at the second point (602), and the
second projection (209) engages in the second depression.
7. The speed sensor according to any of Claims 4 to 6, characterised in that the flexibility of
the first spring (213) is set by a slot (215) in the first spring, and/or
the flexibility of the second spring (214) is set by a slot (216) in the second spring.
8. The speed sensor according to any of Claims 4 to 7, characterised in that a third projection
(403) and a fourth projection (404) are provided on the holding apparatus (204) between its
lower and its upper end,
the third projection (403) faces the inside of the housing (201) and touches the latter, with a
precise fit, at a third point,
the fourth projection (404) faces the inside of the housing (201) and touches the latter, with a
precise fit, at a fourth point, and
the third and the fourth projection (403, 404) are disposed on the holding apparatus (204) at
the same height and diametrically opposed;
9. The speed sensor according to Claim 8, characterised in that the first and the third point on
the inside of the housing (201).lie on a first straight line, the second and the fourth point on the
inside of the housing (201) lie on a second straight line, and the first and the second straight
line is parallel to the height direction of the holding apparatus (204).
10. The speed sensor according to any of Claims 1 to 9, characterised in that the magnetic
sensor (202) has electric lines (220, 221)) and these are laser-welded to the holding apparatus
(204).

11. A gear mechanism, in particular a double clutch gear mechanism, which has:
a gear wheel (130), and
a speed sensor (200) according to any of the preceding claims, for measuring the peripheral
speed of the gear wheel (130).