EP2021658A1

EP2021658A1 - Transmission comprising a device for detecting rotational speed

Info

Publication number: EP2021658A1
Application number: EP07728474A
Authority: EP
Inventors: Kim Führer
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2006-05-19
Filing date: 2007-04-25
Publication date: 2009-02-11
Also published as: US20090188336A1; JP2009537766A; DE102006023553A1; WO2007134934A1

Abstract

The invention relates to a transmission comprising a device for detecting rotational speed. Said device comprises a rotational speed transmitter (21) which is rotationally fixed to a transmission shaft, and a stationary rotational speed sensor by which means the rotational speed of the transmission shaft (3) can be detected from the rotational speed transmitter (21). The rotational speed transmitter (21) extends radially outwards into at least one guide (33, 35) which reduces the axial play of the rotational speed transmitter (21). The inventive transmission ensures an especially reliable determination of the rotational speed of the transmission shaft (3).

Description

Transmission with a Drehzahlabαriffseinrichtunα

The present invention relates to a transmission, in particular for a motor vehicle, with a Drehzahlabgriffseinrichtung having a non-rotatably connected to a Getriebewelie tachometer and a fixed speed sensor mitteis the speed of the gearwheel can be tapped at the tachometer.

From the prior art transmissions are known, the Drehzahlabgriffsemrichtungen for generating a speed signal for a motor vehicle o. Ä. Have. These Drehzahlabgriffseinrichtungeπ essentially comprise a non-rotatably connected to the corresponding transmission shaft signal or speed sensor, which is associated with a fixed speed sensor to tap the speed of the tachometer.

Thus, DE 198 14 758 A1 ailgemeiπ a device for detecting the speed of a shaft. The known device has a non-rotatably connected to the Welie signal generator, which is formed in the manner of a gear wherein the teeth of the gear jeweiis have a steep and a flat Zahnfianke. Furthermore, an analogue Hall-effect sensor is provided, which picks up the rotational speed in the radial direction on the circumference of the toothed wheel, aiso on the teeth. Thanks to the different slope slopes of the two Zahnfianken it is possible, the speed! and to determine the direction of rotation of the shaft with only one sensor and at a constant refresh rate, if the shaft rotates at a very low speed.

DE 103 47494 A1 describes a similar arrangement in which the torque is to be determined on transmission shafts. The known device comprises for this purpose a transmission shaft to which a tachometer gear is rotatably mounted, wherein the tachometer gear turn a associated with fixed speed sensor, which picks up the speed in the radial direction on the circumference of the tachometer gear, so on the teeth. This means that the teeth of the tachometer gear generate when driving past the speed sensor electrical impulses, which are fed to a corresponding evaluation unit.

Another Drehzahiabgriffseinrichtung for a bevel of a motor vehicle is disclosed in DE 102 23 625 A1. In this Drehzahiabgriffseinrichtung, which also includes a signal transmitter and a sensor, the signal transmitter is integrated in a dust cover for a driven side oil seal. The dust cover is located outside the gear housing and rotatably connected to the output side of the transmission, while the sensor is attached to the outside of the housing and the speed decreases in the radial direction on the circumference of the dust cover.

While in the aforementioned Drehzahlabgriffseinrichtungen the speed is tapped in the radial direction, from practice further Drehzahlabgriffseinrichtungen are known in which the speed sensor picks up the speed in the radial direction of the speed sensor, signal generator or tachometer gear.

The known from the prior art Drehzahlabgriffseinrichtun- conditions have proven, but offer in Getriebeweflen that are floating and / or have a large axial play, no adequate solution. Thus, in transmissions with such a transmission shaft is not readily ensured that the speed can be tapped securely on the speed sensor.

The present invention is therefore based on the object to provide a transmission with a Drehzahiabgriffseinrichtung, which also in swimming transmission gear units or, in the case of wear parts, with a large axial play! always ensures a safe tapping the speed.

The solution of this problem is based on the features specified in claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

The transmission of the invention, which can be used for example in a motor vehicle, has a Drehzahiabgriffseinrichtung. The Drehzahlabgriffseinrichtung comprises a rotatably connected to a transmission shaft speed sensor and a fixed speed sensor, by means of which the speed of the transmission shaft can be tapped at the speed sensor. The speed sensor may, for example, be a hail-effect sensor, an induction sensor or the like. The speed sensor extends radially outward into at least one guide which reduces the axial play of the speed sensor. Such a guide may be provided for example on the transmission housing or another transmission part.

The invention has the advantage that the Axialspiei the speed sensor is limited by the guide, so that the speed sensor is held and guided even in a particularly large Axialspiei the gear shaft in a range in which the fixed speed sensor can pick up the speed of the tachometer.

In a preferred embodiment of the transmission according to the invention, the guide cooperates with the speed sensor so that the Axiaispiei the speed sensor can be reduced to a predetermined value. Thus, the predetermined value can be adjusted by appropriate design of the guide to the properties of the speed sensor. In a particularly preferred embodiment of the inventive transmission, the predetermined value is therefore smaller than a predetermined tolerance value of the speed sensor. Under the predetermined tolerance value, for example, the maximum allowable axial clearance of the speed sensor can be understood, in which still a tapping by the speed sensor is possible. In this embodiment, a reliable and secure tapping the speed is always ensured at the speed sensor

In an advantageous embodiment of the transmission according to the invention, the predetermined value is smaller than the axial play of Getriebewelie. In this way, the Drehzahlabgriffseinrichtung can be used in particular in transmissions whose Getriebewelie is floating or has a particularly large axial play.

In order to realize the above embodiment in an advantageous manner, the speed sensor is arranged in a further embodiment of the transmission according to the invention axially displaceable on the transmission shaft

With floating gear shafts, it can also come to a so-called Ta umel motion. In order for the transmission also in this case a secure tapping without damaging the guide or the speed sensor allows the speed sensor is arranged in a particularly preferred embodiment of the transmission according to the invention to the Getriebeweile that the speed sensor relative to the longitudinal axis of the transmission shaft can be inclined. If the transmission technology causes a wobbling motion, then no bending moment is transmitted to the guide via the speed sensor, but rather the speed transmitter tilts counter to the transmission shaft in order to avoid this load.

In a further preferred embodiment of the transmission according to the invention this comprises at least one second Getriebeweile, wherein the Guide is designed as a circumferential groove in or on the second transmission shaft. Thus, an already existing transmission part is used which in addition - if it is, for example, a countershaft - is arranged in the vicinity of the first transmission shaft, so that the speed sensor does not have to have a particularly large diameter, up to the guide in the form of the circumferential groove to get.

In order to ensure that the speed sensor continues to have a lower Axialspiei than the first gear shaft, the second Getriebeweile in an advantageous embodiment of the transmission according to the invention has a lower Axialspie! as the first gear shaft.

In order to keep the Hersteilungsaufwand for the second transmission shaft low, the circumferential groove in a particularly preferred embodiment of the transmission according to the invention on two Nutfianken, which are formed by the mutually facing sides of two adjacent gears on the second Getriebeweile. Such a groove is given in any case at two adjacent gears when they are spaced apart, so that a processing of the transmission shaft, such as 2. B. the insertion of a circumferential groove, is eliminated.

In a further embodiment of the transmission according to the invention, the speed sensor is oriented such that the speed can be tapped in the axial direction of the speed sensor. Since the Abgreif availability of the speed at the speed sensor in such an embodiment depends in particular on the axial play of the speed sensor, the invention reduction of Axiaispiels is particularly advantageous in this embodiment.

To counteract wear on the speed sensor and the guide or circumferential groove, the speed sensor is in a special preferred embodiment of the transmission according to the invention as a speed sensor disc formed on its side facing the speed sensor side recesses. For example, the depressions may be arranged in a circle one behind the other and rotated past the rotational speed sensor so that corresponding pulses are generated in the rotational speed sensor. In contrast to the conventionally used tachometer gears wear is lower in this embodiment, since the recesses are provided only on one side of the tachometer disc, while in the known tachometer gear tooth gaps between the teeth are present, which would wear on both sides by an abutment on soifliche groove flanks , In addition, the depression, in contrast to a through opening, such as a tooth gap, the advantage that another, rotating behind the recess Getriebeteii can not influence or distort the measurement result.

In order to further reduce the wear on the Drehzahigeberscheibe and the guide, the recesses are spaced in a further preferred embodiment of the transmission according to the invention from the edge of the tachometer disc. Consequently, the depression does not pass over into the edge of the rotational speed sensor, as is the case with an outwardly facing tooth space. The rotational speed sensor disc can thus also be guided more smoothly in the guide on the side facing the rotational speed sensor; moreover, a collision between the rotational speed sensor Edge of the recesses and the toothing of the gear on the second gear shaft largely excluded.

According to a further preferred embodiment of the transmission according to the invention, the speed sensor disc is made of a perforated disc and a cover plate which are connected flat to each other. The edges or walls of the recesses are thus predetermined by the perforated disc. whereas the cover plate forms the bottom of the recesses. The hole and cover plate can be welded or soldered together, for example. This embodiment has two major advantages. On the one hand, a particularly flat tachometer disc can be generated, so that the overall transmission length is only marginally increased. On the other hand, the production cost is lower than in a tachometer disc, in which the recesses would have to be introduced into a single, thin disc blank.

In a further advantageous embodiment of the transmission according to the invention, one of the groove flanks is formed exclusively by the teeth of a gear wheel, wherein the side facing the speed sensor side of the speed sensor disc faces this groove flank. Since a groove flank formed by the teeth of the toothed wheel can lead to increased wear on the tachometer disc, it makes sense to turn this groove flank to the more wear-resistant closed side of the tachometer disc.

In accordance with the aforementioned embodiment, one of the groove flanks is formed in a further advantageous embodiment of the transmission according to the invention at least partially by a closed portion of a gear, wherein the speed sensor facing side of the speed sensor disc faces this groove flank and the recesses in the speed sensor disk the closed section are arranged opposite one another. Of course, the opposite arrangement relates only to those recesses which are currently rotated in the circumferential groove.

The advantages achieved by the particular embodiment of the speed sensing device are particularly evident in a further advantageous embodiment of the transmission according to the invention, in which the first transmission shaft, the main shaft and the second transmission shaft, a countershaft with the main body floating between two countershafts.

The invention will be explained in more detail below with reference to an exemplary embodiment with reference to the accompanying drawings. Show it:

Fig. 1 is a schematic representation of an embodiment of the

Transmission with a Drehzahiabgriffseinrichtung,

Fig. 2 is a plan view of the transmission of Fig. 1 in the region of

Drehzahiabgriffseinrichtung,

FIG. 3 is a side view of the transmission of FIGS. 1 and 2 in the region of the rotary tooth tapping device and FIG

Fig. 4 is a front view of the speed sensor disc from the

Fig. 1 to 3.

Fig. 1 shows a schematic illustration of an embodiment of the transmission 1 for a motor vehicle. The transmission 1 is an equiaxed transmission with a drive shaft 2, a main shaft 3 and an output shaft 4, which are arranged one behind the other lying on an axis 5. The main shaft 3 is connected to the output shaft 4 via a planetary gear 6, which is only indicated schematically. There are also two countershafts 7, 8 are provided, which extend parallel to the drive shaft 2, the main white 3 and the output shaft 4 along two axes 9, 10. The main shaft 3 is geiagert with large axial and radial clearance between the drive shaft 2 and the output shaft 4. The transmission 1 further comprises a Gefriebegehäuse 11 through which the ends of the drive and output shafts 2, 4 facing away from the main shaft 3 extend outwards.

To each of the countershafts 7, 8, a drive gear 12, 13 is fixed, which is in engagement with a driven gear 14 of the drive shaft 2, so that the countershafts 7, 8 can be driven by the drive shaft 2. In addition, 7 and 8 further fixed gears 15, 16 and 17, 18 are provided on the countershaft, which are in engagement with the idler gears 19, 20 on the Hauptwelie 3. The fixed gears 15, 17 and the idler gear 19 form the wheelset of the second gear, while the fixed gears 16, 18 and the idler gear 20 form the wheel of the first gear. In order to effect a rotationally fixed connection or a coupling of the main shaft 3 to one of the idler gears 19, 20, at least one switchable coupling device is also provided on the main shaft 3, the illustration of which has been omitted for reasons of clarity.

The transmission 1 also has a speed tapping device for determining the rotational speed of the main shaft 3. The Drehzahiabgriffseinrichtung essentially comprises a tachometer 21 which is rotatably connected to the main shaft 3 and disposed between the Loszahnrädern 19, 20, and a fixed speed sensor 22 which is attached via a support arm 23 (Fig. 3) to the Gefriebegehäuse 11 , The speed of the main shaft 3 can be tapped by means of the speed sensor 22 on the speed sensor 20, wherein the pulses generated in the speed sensor 22 are passed via a line 24 to an evaluation unit 25.

Hereinafter, the Drehzahiabgriffseinrichtung the transmission 1 with reference to Figs. 2 to 4 explained in more detail The speed sensor 21 is formed in the illustrated embodiment as a speed sensor disk 26. The speed sensor disk 26 has recesses 27 in its side facing the speed sensor 22. These recesses 27 are circular and spaced apart in the said side of the Drehzahlgeberschei- 28 provided, as can be seen in particular in Fig. 4, which shows a front view of the speed sensor disk 26. In this case, the depressions 27 are arranged at a predetermined distance from the edge 28 of the rotary indexing disk 26, i. h, these do not go into the edge 28, as is the case with tachometer gears. Also, it does not handle the recesses 27 to continuous openings in the tachometer 26. However, the tachometer disc 26 has a central opening 29 which allows a rotationally fixed attachment to the main shaft 3. The side of the tachometer disc 26, in which the recesses 27 are provided, faces the rotational speed sensor 22, which is oriented in such a way (FIG. 3) that the rotational speed of the main gear 3 can be tapped in the axial direction on the rotational indexer disc 26.

The Drehzahigeberscheibe 26 is made of a perforated disc 30 and a cover 31 hergesteilt, which are connected flat to each other, as can be seen in Figs. 2 and 3. With such a rotational speed disc, the recess flanks are thus formed by the edges of the holes in the perforated disc 30 and the bottom of the recess by the cover 31. This enables the cost-effective production and provision of particularly thin tachometer discs, whereby a lower overall transmission length can be achieved.

The Drehzahigeberscheibe 26 is disposed axially displaceably on the main shaft 3, as illustrated by the double arrow A. In addition, the Drehzahigeberscheibe 26 is connected to the main shaft 3 so that it can be inclined relative to the longitudinal axis 5 of the main shaft 3 (double arrow B). Such a connection with the above-mentioned degrees of freedom can be achieved, for example, by the diameter of the opening 29 in the rotary indexing disk 26 being greater than the diameter of the main shaft 3, which allows said inclinability, while a passable spring (not shown), which extends on the one hand in the main field 3 and on the other hand in a lateral recess 32 in the opening 29 of the tachometer disc 26, causes a rotationally fixed connection.

The fixed gears 15 and 16 are axially spaced from each other fixed to the Vorgeiegewelle 7, so that between the fixed gears 15, 16, a guide 33 is formed in the form of a circumferential groove 34. The same applies to the fixed gears 17, 18 on the countershaft 8, between which a further guide 35 is formed in the form of a circumferential groove 36 The following statements on the guide 33 apply mutatis mutandis to the guide 35,

The circumferential groove 34 includes a first groove flank 37 which is formed from the side of the fixed gear 16. The fixed gear 16 in this case has such a small diameter that the first groove flank 37 is formed exclusively by the side of the toothing 38 of the Fesfzahnrades 18. The circumferential groove 34 further has a second groove flank 39 opposite the first groove flute 37, which is formed by the side of the fixed gear 15, wherein the second groove flank 39 extends both from the side of the toothing 40 and from a close-to-axis closed portion 41 of the fixed gear wheel 15 is formed. The groove base 42 of the circumferential groove 34 is formed by the outer surface of the Vorgeiegewelie 7

The speed sensor disc 26 extends radially outward starting from the main shaft 3 and dips at the edge into the two circumferential grooves 34, 38, so that the axial play of the rotational speed sensor disc 27 is limited by the two groove flanks 37, 38 b2w. is reduced. The Axialspie! the speed sensor disc 26 relative to a stationary part of the transmission, such as the speed sensor 22, is thus reduced to a predetermined value resulting from the axial play between the flanks 37, 38 and the axial play of the countershaft 7 and 8, respectively, wherein the Vorgeiegewelien 7, 8 are stored with low backlash and have a lower Axiaispiel than the floating supported Hauptweil 3. The predetermined value of the axial length of the rotational speed disc 28 is set to be less than a predetermined tolerance value of the rotational speed sensor 22. Also, the predetermined value of the axial displacement of the rotational speed sensor disc 26 is smaller than the axial distance of the main angle 3.

In order to keep the wear on the guides 33, 35 and the tachometer disc 26 low, the side of the tachometer disc 28, that is to say the side formed by the cover disc 31 and closed, faces the first groove flank 37. On the other hand, the rotational speed sensor 22 facing side of the speed sensor disc 26, in which the recesses 27 are provided, the second groove flank 39 faces. In this case, the recesses 27, which are rotated in the circumferential groove 34, arranged such that they are opposite the closed portion 41.

Hereinafter, the operation of the transmission 1 will be explained briefly with reference to FIGS. 2 and 3. During operation of the transmission 1, a strong axial displacement of the floating main shaft 3 can occur. However, the Drehzahigeberscheibe 26 does not fully follow this movement, but rather is held in the region between the two groove flanks 37, 39, wherein the Drehzahigeberscheibe 26 axially displaced along the main shaft 3. As a result of this reduction of the axial play of the rotational speed disc 26 to a value below the permissible tolerance value of the rotational speed sensor 22, a reliable tapping of the rotational speed at the rotational indexer disc 26 is possible at any time independently of the axial displacement of the main shaft 3. Furthermore, the floating main shaft 3 also experiences wobbling movements of the same. In this case as well, the axial clearance of the rotational speed shaper 26, in particular in its edge region, is limited to a predetermined value by the guides 33, 35. decreased value, wherein the inclinability of the tachometer disc 26 relative to the axis 5 of the main shaft 3 causes no loads on the tachometer disc 28 and the guides 33, 35 are applied.

Bezuαszeicheπ

1 gearbox

2 drive shaft

3 main shaft

4 output shaft

5 axis

6 planetary gear

7 Vorgewiegewelle

8 countershaft

9 axis

10 axis

11 gearbox housing

12 drive gear

13 drive toothraci

14 output gear

15 fixed gear

16 fixed gear

17 fixed gear

18 fixed gear

19 loszahn rad

20 lottery wheel

21 speed sensor

22 speed sensor

23 holding arm

24 line

25 evaluation unit

26 tachometer disc

27 wells

28 edge of the speed sensor disc 29 opening

30 perforated disc

31 cover disc

32 lateral recess

33 leadership

34 circumferential groove

35 leadership

36 circumferential groove

37 first groove groove

38 toothing

39 second groove flank

40 toothing

41 closed section

42 groove base

A double arrow

B double-headed arrow

Claims

claims

1. Transmission with a Drehzahlabgriffseinrichtung having a non-rotatably connected to a transmission shaft (3) speed sensor (21) and a fixed speed sensor (22), by means of which the speed of the transmission shaft (3) on the speed sensor (21) can be tapped, thereby geken n draws net that the speed sensor (21) extends radially outward in at least one of the Axiaispiel the speed sensor (21) decreasing guide (33, 35).

2. Transmission according to claim 1, characterized in that the guide (33, 35) cooperates with the speed sensor such that the Axialspiei of the speed sensor can be reduced to a predetermined value.

3. Transmission according to claim 2, characterized geke nnzeichnet that the predetermined value is smaller than a vorbesf in mter tolerance value of the speed sensor (22).

4. Transmission according to one of claims 2 or 3, characterized Porsche Style nzeich net that the predetermined value is smaller than the axial play of the gear shaft (3).

5. Transmission according to one of the preceding claims, characterized g e - ken nze ichn et, that the speed sensor (21) is arranged axially displaceably on the transmission shaft (3).

6. A transmission according to one of the preceding claims, characterized g e - ken nze ichn et, that the speed sensor (21) is arranged on the transmission shaft (3) that this with respect to the longitudinal axis (5) of the transmission shaft (3) is tilted.

18

7. A transmission according to one of the preceding claims, characterized g e - ken nze ichn et, that the transmission (1) at least one second transmission shaft (7, 8), wherein the guide (33, 35) as a circumferential

Groove {34, 36) in or on the second GetriebeweÜe (7, 8) is formed.

8. Transmission according to claim 7, characterized geke nnzeichnet that the second transmission shaft (7, 8) has a lower axial play than the first transmission shaft (3).

9. A transmission according to any one of claims 7 or 8, characterized Porsche Style nzeich net, that the circumferential groove (34, 38) has two groove flanks (37, 39) which from the mutually facing sides of two adjacent gears (15, 16; 18) are formed on the second transmission shaft (7; 8}.

10. A transmission according to one of the preceding claims, characterized g e - ken nze ichn et, that the speed sensor (22) is oriented such that the rotational speed in the axial direction of the speed sensor (21) can be tapped.

11. A transmission according to claim 10, characterized Porsche Style nzeich net, that the speed sensor (21) as a speed sensor disc (26) is formed on its the speed sensor (22) side facing recesses (27).

12. Transmission according to claim 11, characterized Porsche Style nzeich net that the recesses (27) from the edge (28) of the tachometer disc (26) are spaced.

13. The transmission as claimed in claim 11, characterized in that the speed sensor disk (26) is produced from a perforated disk (30) and a cover disk (31) which are connected to each other in a planar manner.

14. A transmission according to any one of claims 11 to 13, characterized in that one of the groove flanks (37) is formed exclusively by the toothing (38) of a toothed wheel (16, 18), wherein the speed sensor ( 22) facing away from the speed sensor disk (26) facing this groove flank (37).

15. A transmission according to any one of claims 11 to 14, characterized in that one of the groove flanks (39) is at least partially formed by a closed section (41) of a gear wheel (15, 17), wherein the rotational speed sensor ( 22) facing side of the speed sensor disc (26) of this Nutfianke (39) faces and the recesses (27) in the speed sensor disc (26) the closed portion (41) are arranged opposite one another.

16. Transmission according to one of claims 7 to 15, characterized g e - ken nze ichn et, that the first Getriebeweüe (3), the main shaft and the second transmission shaft (7, 8) is a Vorgelegeweile, wherein the main shaft is floatingly mounted between two countershafts