EP0566111A1 - Switch signalling changement of position and acceleration - Google Patents

Abstract

A switch (1) signals orientation changes and accelerations of its housing. The switch housing contains a permanent magnet (13) (which is supported such that it can move) and at least one reed switch (15). The permanent magnet (13) is suspended like a pendulum. The reed switch (15) is arranged underneath the circular segment described by the pendulum, in the region in which the magnetic field acts. The longitudinal axis (16) of the reed switch (15) is aligned approximately in the direction of the pendulum oscillations. <IMAGE>

Description

The invention relates to a position signaling changes and accelerations of its housing switch with the features of the preamble of claim 1.

Such switches are known per se. They are used, for example, in motor vehicles, where they are intended to trigger a switching operation when a predetermined limit value for acceleration or deceleration is exceeded, for example switching on an optical or acoustic signal, inflating a so-called “airbag” or the like. or acceleration-sensitive sensor on a mercury switch, in which a movably mounted small amount of mercury short-circuits two electrodes when a predetermined limit value is exceeded.

To achieve the same purpose, it is also known to replace the mercury switch with a movably mounted magnet, in the field of which a reed switch is arranged. If the magnet is subjected to an acceleration or deceleration of a predetermined magnitude, the associated change in the magnetic field causes the reed switch to change its switching state, which can be used in the same way as the switching operation of the mercury switch mentioned above. Position and acceleration sensitive switches with a movably mounted permanent magnet and at least one reed switch as active elements are known for example from DE 40 32 717 A1 . There the permanent magnet is suspended in a pendulum-like manner on a switch housing. Changes in position and accelerations of the switch housing cause a movement of the permanent magnet relative to the reference system of the switch housing and in this way cause a change in the switching state of the reed switch which is fixedly attached to the switch housing at certain limit values of changes in position or acceleration.

The previously known arrangements consisting of permanent magnet and reed switch are built in some cases in an extremely complex manner or because of them their arrangement of the active elements a high response threshold or an intolerably large hysteresis of the switching on and off.

The invention has for its object to develop the known position and acceleration sensitive switch with a movable permanent magnet and at least one reed switch as active elements, with the aim of simplifying their structure, increasing their response accuracy and their on and off hysteresis to reduce. This object is achieved by the combination of features of claim 1.

This arrangement ensures that the switch responds on the one hand even at relatively low accelerations or decelerations, that is to say it is highly sensitive. On the other hand, however, the reed switch acts due to its longitudinal orientation in the direction of vibration with its magnetizable parts as a magnetic brake and proportionally also as eddy current damping, so that wild vibrations of the pendulum-suspended magnet are suppressed.

The orientation of the reed switch also enables the space-saving construction of the switch housing that accommodates the reed switch and the permanent magnet. The swivel range of the pendulum must be taken into account when dimensioning the switch housing anyway. No additional space is therefore required for the longitudinal orientation of the reed switch.

Transversely to its longitudinal orientation, the reed switch can also be installed pivoted by a certain angle by an imaginary extension of the pendulum longitudinal axis which is in the rest position, without impairing the narrow construction of the switch housing.

Claim 2 ensures the necessary influence on the switching state of the reed switch by the special arrangement of the permanent magnet. In addition, the magnetization direction lying in the pendulum plane continues to support the narrow construction of the switch housing in the case of a large number of embodiments of permanent magnets.

Claims 3 and 4 relate to advantageous arrangements of polarization direction of the permanent magnet and longitudinal axis of the reed switch. According to claim 4, the hysteresis of the magnetizable parts of the reed switch is further reduced, so that an improvement in the response accuracy and responsiveness of the switch is achieved. The improved response characteristics of the switch enable the permanent magnet to have a shorter swivel path along its pendulum level in order to still achieve sufficient response accuracy and fineness. The shorter swivel path in turn enables a shorter pendulum length. Overall, the required volume of the switch housing is further reduced.

According to claim 5, the permanent magnet is a bar magnet. Bar magnets can be produced in very small dimensions, so that they are particularly suitable for the application proposed here. All known magnetic materials can be used.

Claims 6 and 7 enable an effective fixation of the permanent magnet within the switch housing. This ensures that the permanent magnet performs the required oscillations. As a molded plastic part, the pendulum frame is easy and inexpensive to manufacture. Since the pendulum frame has a certain degree of mechanical stability, wild vibrations of the permanent magnet can be dampened.

The pendulum housing for the permanent magnet is preferably formed on the end region of the pendulum frame facing the reed switch. As a result, the center of gravity of the pendulum is very low, so that its damping properties are further improved. The deep arrangement of the pendulum housing also enables the reed switch to be better influenced by the permanent magnet.

The mass of the pendulum frame and the pendulum housing itself also act as damping for the pendulum vibrations.

If the inherent mass of the pendulum frame, the pendulum housing and the permanent magnet is not sufficient, it is advantageous according to claim 8, in addition to the permanent magnet, at least one further mass body in the To arrange a pendulum housing, which allows the setting range to be expanded considerably.

By varying the masses, different pendulum properties such as e.g. Achieve tripping characteristics and damping. Coordinates of the center of gravity can be changed using differently shaped mass bodies. As a result, the pendulum properties can also be changed in a simple manner.

According to claims 9 and 10, mass body and permanent magnet are mechanically stable fixed. The days of such a pendulum are also simplified.

In order to design the proposed switch as an easy-to-use component, it is proposed according to claim 11 that the above-mentioned functional parts, namely the pendulum frame together with permanent magnet and possibly additional mass body on the one hand and the reed switch on the other hand are combined in a switch housing to form a structural unit.

This switch housing is equipped according to claim 12 with connecting elements in the form of plug pins, solder pins or cables, so that the entire switch can be arranged as a functional part on printed circuit boards or in other electrical or electronic circuits. The simple bending of the connector pins or soldering pins enables the switch housing to be brought into a desired inclined position relative to the printed circuit board or other mounting supports. The switch is therefore also effective as a tilt switch and triggers various functions at very specific tilt positions.

According to claims 13 and 14, a plurality of switch housings, which already form a functional unit, with an integrated pendulum frame, permanent magnet, optionally additional mass bodies and associated reed switches are arranged in a common protective housing. Here, the functional units have pendulum planes aligned parallel to one another, the individual switches, however, being arranged in different angular positions with respect to the base plate of the protective housing. As a result, there are different threshold values for triggering certain functions available. In this way it is possible to combine several switches that are functionally independent of one another to form a structural unit.

Especially when there are several functional units or switches arranged side by side in a protective housing, a narrow construction of the individual switch is advantageous in order to be able to keep the overall volume of the protective housing itself small.

The claims 15 and 16 relate to advantageous ways to achieve different inclination or angular positions of individual switches with technically simple means. The switch housing is preferably fixed to the fixing axis by friction in order to enable mechanically stable fixing.

According to claim 17, the individual functional units or switches are arranged in a protective housing in different spatial directions, so that inclinations, accelerations or decelerations in different directions can be measured or at least detected with the overall element. In this way, a whole cascade of differently sensitive switches can be formed. Such switch combinations can also be used, for example, as threshold value transmitters for an ABS system in motor vehicles.

Claim 18 relates to a measure for the mechanically stable final fixation of the switches arranged in a protective housing. As a result, the geometric alignment of the pendulum level of a switch is always retained. This ensures that certain functions are triggered at the initially set limit or threshold values over the entire service life of the switches.

In order to dampen the vibrations of the pendulum frame even further, the switch housing is filled with damping fluid. The effectiveness of the damping depends on both the amount and the viscosity of the damping fluid.

Claim 20 enables an inexpensive and simple manufacture of the switch housing. The switch housing can be easily installed without additional aids, such as additional connecting elements.

Fig.1

eine Draufsicht eines einseitig geöffneten Schalters.

Fig.2

eine geschnittene Seitenansicht des geschlossenen Schalters entsprechend der Schnittlinie II-II in Fig.1.

Fig.3

die Draufsicht des Pendelrahmens.

Fig.4

eine Seitenansicht des Pendelrahmens.

Fig.5

eine Rückansicht des Pendelrahmens.

Fig.6

die Draufsicht einer weiteren Ausführungsform des Schalters.

Fig.7

die Rückansicht des Schalters in Fig.1.

Fig.8

die Draufsicht einer Gehäuseschale des Schalters aus Fig.1.

Fig.9

die geschnittene Seitenansicht der Gehäuseschale entsprechend der Schnittlinie IX-IX in Fig.8,

Fig.10

die Draufsicht einer zweiten Gehäuseschale des Schalters aus Fig.1,

Fig.11

die geschnittene Seitenansicht der Gehäuseschale entsprechend der Schnittlinie XI-XI in Fig.10,

Fig.12

eine Seitenansicht des einen oder mehrere Schalter enthaltenden Schutzgehäuses, teilweise aufgeschnitten.

The invention is explained in more detail with reference to the exemplary embodiments shown in the figures. Show it:

Fig. 1

a plan view of a switch open on one side.

Fig. 2

a sectional side view of the closed switch according to the section line II-II in Fig.1.

Fig. 3

the top view of the pendulum frame.

Fig. 4

a side view of the pendulum frame.

Fig. 5

a rear view of the pendulum frame.

Fig. 6

the top view of another embodiment of the switch.

Fig. 7

the rear view of the switch in Fig.1.

Fig. 8

the top view of a housing shell of the switch from Fig.1.

Fig. 9

the sectional side view of the housing shell according to the section line IX-IX in Figure 8,

Fig. 10

the top view of a second housing shell of the switch from Figure 1,

Fig. 11

the sectional side view of the housing shell according to the section line XI-XI in Fig.10,

Fig. 12

a side view of the protective housing containing one or more switches, partially cut away.

In Fig. 1 the switch 1 can be seen with a housing shell acting as a bottom shell 2. The bottom shell 2 has approximately the shape of an isosceles triangle. However, the connection area of the two triangle legs opposite the base side is rounded off in the manner of a circular arc. In this area, a pendulum frame 3 is fixed in place on a pendulum axis 4. The pendulum frame 3 is pivotally suspended in the switch housing by means of the pendulum axis 4. Opposite the pendulum axis 4 in the height direction 5 of the switch 1, a pendulum housing 6 is integrally formed on the pendulum frame 3. The pendulum frame 3, starting from the pendulum axis 4 in the direction of the pendulum housing 6, has a conically expanded outline shape. A mass body 8 is inserted in a form-fitting manner in the receiving space 7 of the pendulum housing 6. The mass body 8 has a square outline shape in FIG. For example, it can be a brass block. By mass body 8 with the same dimensions, but different masses, the damping behavior of the pendulum frame 3 can be varied.

The pendulum housing 6 is penetrated on one side by a through hole 10 in a longitudinal direction 9 of the switch 1. The mass body 8 is partially penetrated by a fixing bore 11 running in the longitudinal direction 9. It extends somewhat along the longitudinal direction 9 beyond the longitudinal longitudinal axis 12 which runs parallel to the vertical direction 5.

The through bore 10 and the fixing bore 11 are congruent when viewed in the longitudinal direction 9 and serve for the positive reception and fixing of a permanent magnet 13 designed as a cylindrical bar magnet. The direction of polarization thereof runs parallel to the longitudinal direction 9.

A reed switch 15 with a longitudinal axis 16 running parallel to the longitudinal direction 9 is arranged between the pendulum housing 6 and the side wall of the base shell 2 running in the longitudinal direction 9 and acting as a base wall 14. The longitudinal axis 16 and the pendulum longitudinal axis 12 are arranged perpendicular to one another. The reed switch 15 is located approximately equally on both sides of the longitudinal axis 12 of the pendulum.

The reed switch 15 is fixed with its connecting wires 17 to clamping projections 18 of the base shell 2. The clamping projections 18 are preferably integrally formed on the base shell 2 and extend parallel to the depth direction 19 into the interior 21 of the switch housing delimited by the base shell 2 and a cover shell 20 (FIG. 2). The connecting wire 17 is clamped between the two circular clamping ends of a clamping projection 18 in FIG. Immediately next to the clamping projection 18, the connecting wire 17 is bent to extend in the height direction 5. In order to fix the connecting wires 17 stationary in the depth direction 19 as well, the clamping projections 18 of the base shell 2 and two further clamping projections 18 of the cover shell 20 are in contact with one another with their surfaces facing one another in the assembled state of the switch 1 (FIG. 2). As a result, the reed switch 15 is mounted in a sufficiently stable manner.

The switching state of the reed switch 15 is influenced by the oscillations of the permanent magnet 13. The pendulum plane is spanned by the height direction 5 and the longitudinal direction 9 arranged perpendicular thereto. The pendulum frame 3 describes a circular segment delimited by the side walls of the switch housing during its pendulum movement.

On the base wall 14 of the base shell 2, a shell extension 22 extending in the height direction 5 is integrally formed. It lies in a plane spanned by the height direction 5 and the longitudinal direction 9. The two outline edges of the shell arm 22 projecting from the base wall 14 form an isosceles triangle together with the base wall 14 itself, the angle lying opposite the base wall 14 in the vertical direction 5 and being enclosed by the outline edges of the shell arm 22 being obtuse. In the area of this angle, the outer edge of the shell boom 22 is rounded. In this area, the shell arm 22 is initially rectangular in the height direction 5 and then cut immediately thereafter as a circular switch bearing 23. The switch bearing 23 breaks through the shell arm 22 in the depth direction 19 (FIG. 2) and preferably frictionally engages around a fixing axis (not shown here) for mounting the switch housing. The switch housing can be pivoted on the fixing axis, so that different inclination positions between the base wall 14 and the base plate 24 of a protective housing 25 (FIG. 12) can be set.

Between the switch bearing 23 and the base wall 14, the shell extension 22 is pierced by a wire bore 26 that is smaller than the switch bearing 23. It serves for the passage of a connecting wire 17. The wire bore 26 of the cover shell 20 is provided for the second connecting wire 17. If the switch 1 is soldered to the ends of its connecting wires 17 on a printed circuit board, the inclination of the base wall 14 and thus of the entire switch 1 can be adjusted or changed by pivoting about an imaginary pivot axis penetrating the wire bore 26 in the depth direction 19.

A bearing plate 27 fixed to the base shell 2 and to the cover shell 20 is provided for the pivotable mounting of the pendulum axis 4 (FIG. 2). The bearing plates 27 are arranged parallel to one another and run in the height direction 5. They rest directly on projections projecting into the interior 21 and are fixed in place on two cylindrical fixing pins 28. The projections and the fixing pins 28 are preferably an integral part of the base shell 2 or the cover shell 20. Along the depth direction 19, the bearing plate 27 is of a pendulum axis bearing 29 effective hole pierced. The two pendulum axle bearings 29 serve to pivotally fix the pendulum axis 4.

In Fig.3 - Fig.5 it can be seen that the pendulum frame 3 with the exception of the through hole 10 is a symmetrical component. In Fig. 3 it can be seen that the receiving space 7 for the mass body 8 is freely accessible from the plane of the drawing. In this way, the mass body 8 can be subsequently inserted into the pendulum frame 3. The receiving space 7 can be divided into two parts. In the plane of the drawing in FIG. 3, the portion of the receiving space 7 that faces away from the hollow cylindrical spherical bearing 30 penetrated by the pendulum axis 4 has a rectangular outline shape. This is followed by a trapezoidal section that tapers conically in the direction of the self-aligning bearing 30. The first partial area is designed to be enlarged in the longitudinal direction 9 with respect to the mass body 8. However, the outline of the second section is dimensioned such that the two corner edges of the hexagonal pendulum housing 6 facing the self-aligning bearing 30 cooperate with the side wall lying opposite in the height direction 5 and clamp the mass body 8 between them (FIG. 1). For a mechanically stable clamping, the elasticity of the pendulum frame 3 designed as a plastic injection-molded part can be used. The distance between the inner walls of the pendulum housing 6 opposite each other in the height direction 5 can be dimensioned slightly smaller than the corresponding extent of the mass body 8 in order to achieve its fixed fixation.

A further embodiment of the switch 1 can be seen in FIG. 6. The reed switch 15 is integrated in the base wall 14 of the base shell 2. Its longitudinal axis 16 runs perpendicular to the longitudinal axis 12 of the pendulum. However, the longitudinal axis 12 of the pendulum and the direction of polarization of the permanent magnet 13 are not perpendicular to one another as in FIG. 1, but form an acute angle. The mass body 8 and the permanent magnet 13 are fixed side by side in the pendulum housing 6.

The approximately bell-like outline shape of the base shell 2 with its outer wall 31 can be seen in FIG. Furthermore, it can be seen that the outer wall 31 and the outer side of the shell boom 22 lie flat in a plane spanned by the height direction 5 and the longitudinal direction 9. The same statements apply to the outer wall 31 of the cover shell 20.

It can be seen in FIGS. 8-11 that the base shell 2 and the cover shell 20 are configured identically with regard to their essential functional parts. In addition, the bottom shell 2 and the cover shell 20 are symmetrical with respect to the longitudinal axis 12 of the pendulum. This significantly simplifies the manufacture of the switch housing.

The base shell 2 and cover shell 20 are manufactured as injection molded plastic parts. Both housing shells differ essentially in the design of their edges of the shell side walls which lie against one another in the assembled state of the switch 1. The side walls of the base shell 2 are cut out in the form of an inner groove 32 in their surface area to be contacted with the cover shell 20 over the entire circumference of the base shell 2. The side walls of the cover shell 20 are incised in the surface area to be contacted with the base shell 2 over the entire circumference of the cover shell 20 on the outside as an external groove 33. The inner groove 32 and the outer groove 33 are dimensioned such that the bottom shell 2 and the cover shell 20 snap together like a spring when the switch 1 is installed.

12 shows an embodiment in which a plurality of switches 1, each surrounded by its own switch housing, are mounted in a common protective housing 25. The protective housing 25 is drawn partially cut away, so that one of the switches 1 mounted in the interior of the protective housing 25 is visible. This switch 1 is arranged inclined within the protective housing 25, so that its base wall 14 forms an angle 34 with the base plate 24 of the protective housing 25, which is set depending on the desired response limit value of the switch 1. The protective housing 25 is fixed in place on the reference system to be moved by means of lateral fastening means 35, which are designed as bores for screw fastening in FIG. 12.

The protective housing 25 in FIG. 12 is a pot housing with the base plate 24 as a pot bottom with adjoining side walls and with a pot lid 36 that covers and covers the pot like a hood. A fixing axis for adjusting the inclination of the switch housing is not provided in the embodiment of FIG. 12. Rather, the individual switches 1 are twisted on a circuit board with the aid of their connecting wires 17 and / or inclined to achieve different spatial directions and inclination positions for the individual switches 1. The interior of the pot with the base plate 24 as the pot base is sprayed out with a sprayable composition, for example up to half the pot height. The pot lid 36 is placed on the pot and the entire protective housing 25 is rotated by 180 °, so that the pot lid 36 now forms the bottom. In this way, the abutting surfaces of the pot and pot lid 36 are wetted by the still liquid spray compound. After the spray compound has hardened, the pot and the pot lid 36 are connected to one another in a mechanically stable manner and the switches 1 are finally fixed. Reference symbol list 35 Fasteners 1 counter 36 Pot lid 2nd Bottom shell 3rd Pendulum frame 4th Swing axle 5 Height direction 6 Pendulum housing 7 Recording room 8th Mass body 9 Longitudinal direction 10th Through hole 11 Fixing hole 12th Longitudinal pendulum axis 13 Permanent magnet 14 Base wall 15 Reed switch 16 Longitudinal axis 17th Connecting wire 18th Clamping projection 19th Depth direction 20th Lid shell 21 inner space 22 Shell boom 23 Switch bearing 24th Base plate 25th Protective housing 26 Wire hole 27th Bearing plate 28 Fixing pin 29 Self-aligning axle bearings 30th Self-aligning bearings 31 Outer wall 32 Inner groove 33 External groove 34 angle

Claims (20)

Changes in position and accelerations of its housing signaling switch (1) with movably mounted permanent magnet (13) and at least one reed switch (15) as active elements, wherein - The permanent magnet (13) is suspended in the manner of a pendulum and - The reed switch (15) is arranged below the circle segment described by the pendulum in the effective range of the magnetic field characterized,
that the longitudinal axis (16) of the reed switch (15) is aligned approximately in the direction of the pendulum vibrations. Switch according to claim 1,
characterized,
that the direction of polarization of the permanent magnet (13) lies in the pendulum plane. Switch according to claim 2,
characterized,
that the direction of polarization is approximately perpendicular to the longitudinal axis (16) of the reed switch (15). Switch according to claim 2,
characterized,
that the direction of polarization is approximately parallel to the longitudinal axis (16) of the reed switch (15). Switch according to one or more of the preceding claims,
characterized,
that the permanent magnet (13) is a bar magnet. Switch according to one or more of the preceding claims,
characterized,
that the permanent magnet (13) is arranged on a pendulum frame (3). Switch according to claim 6,
characterized,
that the pendulum frame (3) is a plastic injection molded part with a pendulum housing (6) for receiving the permanent magnet (13). Switch according to claim 7,
characterized,
that in addition to the permanent magnet (13) at least one further mass body (8) is arranged on the pendulum frame (3), in particular in the pendulum housing (6). Switch according to claim 8,
characterized,
that the mass body (8) lies positively in the pendulum housing (6). Switch according to claim 8 or 9,
characterized,
that the permanent magnet (13) for its fixed fixation lies positively in a fixing hole (11) passing through the mass body (8). Switch according to one of the preceding claims,
characterized,
that the pendulum frame (3) together with the permanent magnet (13) and possibly additional mass body (8) on the one hand and the reed switch (15) on the other hand are combined in a switch housing to form a structural unit. Switch according to claim 11,
characterized,
that the switch housing is equipped with connecting elements in the form of plug pins, solder pins [= connecting wires (17)] or cables. Switch according to claim 11 or 12,
characterized,
that several, each forming a functional unit switch housing with Integrated pendulum frame (3), permanent magnet (13), possibly mass body (8) and assigned reed switch (15) are arranged in a common protective housing (25). Switch according to claim 11, 12 or 13,
characterized,
that one or more functional units, each consisting of a pendulum frame (3), permanent magnet (13), possibly mass body (8) and reed switch (15) are arranged in a protective housing (25), the switch housing together with the setting of the desired response threshold the parts therein are inclined relative to a base plate (24) of the protective housing (25). Switch according to claim 14,
characterized,
that the inclination of the functional unit is adjustable by pivoting the switch housing on a fixing axis extending through the switch housing parallel to the pendulum axis (4) of the pendulum frame (3) in a switch bearing (23). Switch according to claim 15,
characterized,
that the switch bearing (23) is arranged approximately in the longitudinal direction of the pendulum (12) opposite the pendulum axis (4) in an end region protruding from the switch housing [= shell arm (22)]. Switch according to claim 13 or 14
characterized,
that the functional units arranged in a common protective housing (25), consisting of a pendulum frame (3), permanent magnet (13), possibly mass body (8) and reed switch (15), are arranged with their pendulum planes in different spatial directions. Switch according to one or more of claims 13 to 17,
characterized,
that the interior of the protective housing (25) is potted with the switch housing or switches arranged in their inclined position for their final fixing. Switch according to one of the preceding claims,
characterized,
that the switch housing is completely or partially filled with damping fluid. Switch according to one or more of the preceding claims,
characterized,
that the switch housing is a double-shell molded plastic part - With two resiliently lockable housing shells [= bottom shell (2), cover shell (20)] and - With an interior (21) delimited by the housing shells [= bottom shell (2), cover shell (20)] for receiving the pendulum frame (3), the permanent magnet (13) and, if applicable, the mass body (8) is, whose approximately central division level is the pendulum level.

Images