DE9014753U1 - Speed measuring arrangement - Google Patents

Description

Description

6 Speed measuring arrangement

&bgr; The invention relates to a speed measuring arrangement (tachometer) which is used for

&bgr; Use in motor vehicles, but also for monitoring electrical

10 engines, working machines, etc. Speed measuring

11 Arrangements of this type traditionally work according to the generator

12 principle. The part to be monitored is usually connected to a rotating magnet that rotates in a fixed coil arrangement. In the coil

14, an electrical voltage is induced which is proportional to the rotation

15 number increases. Since in most cases it is difficult or impossible to arrange the the rotating magnet directly on the part to be monitored, the &igr;? magnet is usually connected to it via a shaft.

ie The state of the art also includes speed measuring arrangements,

µ whose speed sensor consists of a combination of rotary magnets with im-

21 pulse wire sensors. The rotary magnets can be small rod

22 magnets or magnetic plates or magnetic foils, which are in ge-

23 are suitably connected to the part to be monitored. The magnetic

24 plates can be easily glued onto the part to be monitored.

25 Instead of small bar magnets or magnetic plates,

26 magnetic pole wheels are used, which have an alternating sequence

27 of north and south poles. When we refer to "rotating magnets"

28, all these possible embodiments are always included with

29 is meant.

31 Pulse wire sensors are special components that are embedded in a magnetic

32 alternating field emit voltage pulses of several volts. The pulse energy

33 energy is completely taken from the alternating magnetic field.

34 Sensors themselves do not require any additional power source. The

35 sensors is enough to power an electronic meter or

se also to control a light-emitting diode directly. To measure the speed, the

37 Output of the pulse wire sensors usually via an electronic

38 pass circuit connected to the input of a counter. To operate the

23 October 1990

&igr; like counter or matching circuits, however, several connecting lines

2 connections are required, which are used to supply and remove the impulses as well as to supply

3 supply of auxiliary power. However, these connecting lines in particular are

4 Motor vehicle is hardly tolerable, since the requirement is to reduce the number of

5 cable connections for reasons of safety, clarity and also

6 to reduce the weight to a minimum.

8 The invention is based on the object of improving the known speed measuring arrangements

βgr; nitions whose speed sensors consist of a combination of rotary magnets

10 with pulse wire sensors, so that their operation

11 is possible with only one single supply line and that a compact

12 unit is created, which is easily at the relevant points of the force

13 vehicle or other machine to be monitored.

is To solve this problem, it is proposed that the pulse wire sensor

together with a light-emitting diode connected to it in a

17 common housing and this housing has a connection for

18 has an optical waveguide, the other end of which is connected to a light-sensitive

19 can be connected to a suitable electronic converter.

21 The idea underlying the invention therefore consists mainly

22 in combining the parts "pulse wire sensor" and "light emitting diode" compactly in one

23 housings and to connect this housing with a connection for

24 to be equipped with an optical fibre.

26 In another embodiment of the invention, a rotary

27 magnet must be included in the housing; or precautions must be taken

28, the first mentioned housing with pulse wire sensor and light

29 diode so that it can be connected to a second housing, which

30 magnets can be coupled.

32 The connection for the optical fiber is preferably a plug connection

33 socket into which one end of the optical fiber is simply plugged

34. The bushing should preferably have a stop,

35 which serves as a plug-in limit for the optical fiber. This ensures that the optical fiber is always securely inserted into the connector

37 and that the optical conditions at the entrance of the optical waveguide

38 are always the same.

23 October 1990

2 The proposed device or measuring arrangement has the advantage that it

3 is a handy and - as the task requires - easy to install in the engine or

4 part to be applied to the machine to be monitored. The only

5 Connection between speed sensor and downstream electronic

6 see converters together with counting, display and, if necessary, recording devices

7 The transmission then consists only of an optical fiber, for example

&bgr; a fiber optic cable, which due to its high flexibility and its

o ring weight as well as its small diameter dimensions easily

10 in motor vehicles and other machines. The required

11 light-sensitive electronic converters and downstream amplifiers

12 ker, display and, if necessary, recording units are to be used with the

13 existing microelectronics can be manufactured easily and in a space-saving manner.

is Photodiodes, phototransistors, and photodiodes are used as light-sensitive converters.

16 Photoresistors may also be considered.

ie The invention is explained in more detail below with reference to the accompanying drawing.

19 purified. They represent:

21 Fig. 1 shows a schematic longitudinal section through a simple embodiment

22 form of a speed sensor falling within the scope of the invention

23 mers;

24 Fig. 2 is a section through Fig. 1 rotated by 90°;

25 Fig. 3 a longitudinal section through an embodiment with integrated

26 rotary magnets;

27 Fig. 4 is a plan view, partly in section, of an arrangement according to Fig. 3;

28 Fig. 5 a circuit diagram.

30 For a general description of the arrangement, please refer to Fig. 5.

31 sen. A rotary magnet 1 is connected to the part to be monitored, in which

32 it is a bar magnet, a magnetic disk, a magnetic pole wheel or the like.

33. The rotary magnet 1 rotates during operation of the arrangement

34 its axis of rotation 2 in a direction of the double arrow 3. The rotary magnet 1

35 can be arranged directly on the part to be monitored or can be connected to it via a shaft or similar. The rotating magnet used here is

37 also a thin magnetic disk can be considered, which in suitable cases

3&bgr; can be attached directly to the part to be monitored.

23 October 1990

2 When the rotary magnet 1 rotates, it induces in the pulse wire sensor

3 an electrical voltage which this sensor generates in the form of voltage pulses

4 to the LED 5. The diode sends the pulses according to the

5 emits light pulses which are directed to the input opening 6 of the optical waveguide

6 ters 7 fall. This optical fiber transmits the light pulses with extremely low losses

7 and releases it again at the exit opening 8 with high intensity. &bgr; Experiments have shown that in this way it is possible to

&bgr; LED 5 emitted light pulses over several meters without nominal

10 significant attenuation. The energy emitted from the output opening 8

11 light pulses hit the light-sensitive electronic wall

12 ler 9, which converts the light pulses back into electrical impulses.

&eegr; In the illustrated embodiment, the converter 9 is a photodiode, which

is the resistors R1, R2 and R3 form a bridge circuit. Depending on the

16 lighting state of the diode, the voltage balance of the bridge

&igr;?. The resulting impulses are transmitted via the condensate

18 tor C1 to the input of the integrated amplifier 10. From the output

&igr;&thgr; of this amplifier, the pulses reach the Schmidt trigger.

20 amplifier 11 and from there via the diode D2 and the resistors R10

21 and R11 to the two transistors T1 and T2, the latter of which is connected to the output 12

22 provides the processed tachometer signal.

25 In Fig. 1, a simple embodiment of the invention is shown for example

26. It can be seen that the pulse wire sensor 4 together with the

27 light-emitting diode 5 is arranged in a common housing 13. The device

28 housing 13 has a connection 14 for an optical fiber 15, the

29 other end (see Fig. 5) with the light-sensitive electronic wall-

30 ler 9 is connectable.

32 The housing 13 can be attached in a suitable manner to the rotary magnet of the

33 guard part. It has a special design

34 form a snap closure 16, with which it can be connected to another,

35 similar housing can be coupled, in which, for example, the rotating magnet is located.

October 23, 1990

&igr; In Fig. 2, the embodiment according to Fig. 1 is shown again, wherein the

2 Representation is rotated by 90° around the longitudinal axis.

4 Fig. 3 shows an embodiment in which the housing 13 is

5 not shown in detail snap lock 16 to another housing 17

6. The housing 17 extends there at a right angle to the

&zgr; Housing 13, an arrangement which is not absolutely necessary. In the

8 Housing 17 houses the rotary magnet 1 in an arrangement which

&bgr; consists of the bracket 18, the pivot bearing 19 and the rotary shaft 20.

10 This rotary shaft is used to operate the arrangement with the monitored

11 part of the machine, which then has the advantage that the com-

12 packets, the measuring arrangement shown in Fig. 3 only via the optical waveguide

13 to 15 is to be connected to the following circuit parts.

Fig. 4 shows the arrangement according to Fig. 3 in cross section.

23 October 1990

List of reference symbols

1 2 Rotary magnet 3 Rotation axis 4 Double arrow 5 Pulse wire sensor 6 led 7 Entrance opening 8th optical fiber 9 Exit opening 10 Converter 11 amplifier 12 Amplifier 13 Exit 14 Housing 15 Connection 16 optical fiber 17 Snap closure 18 Housing 19 bracket 20 Pivot bearing Rotary shaft

23 October 1990

Claims (1)

2/13-90855 23 October 1990 5 Claims s 1. Speed measuring arrangement (tachometer) with speed sensor and 9 display or recording unit, whose speed sensor has a com- 10 combination of a rotary magnet with a pulse wire sensor, 11 characterized by 12 that the pulse wire sensor (4) together with a connected 13 in which the light-emitting diode (5) is arranged in a common housing (13) &eegr; and this housing (13) has a connection (14) for an optical waveguide (15) is, the other end of which can be connected to a light-sensitive electronic ie converter (9). is 2. Speed measuring arrangement (tachometer) with speed sensor and 19 display or recording unit, whose speed sensor is a combination 20 of a rotary magnet with a pulse wire sensor, 21 characterized by 22 that the rotary magnet (1) and the pulse wire sensor (4) together with 23 a light-emitting diode (5) connected thereto in a common 24 housing (13) are arranged and this housing (13) has a connection (14) 25 for an optical waveguide (15) whose other end is connected to a 26 light-sensitive electronic transducers (9). 28 3. Speed measuring arrangement according to claim 1 or 2, 29 characterized by so that the connection (14) for the optical fiber (15) is a plug connection 31 socket, which has a stop as a plug-in limit for the light wave 32 conductors. 34 4. Speed measuring arrangement according to one of the preceding claims, 35 characterized by se that the housing (13) is connected via snap connections (16) to a housing (17), 37, which contains the rotary magnet (1), can be coupled. October 23, 19&THgr;0 (U:\AN\80855-2.TXT)