WO2017101926A1

WO2017101926A1 - Gearbox with directly mounted torque detection device, and method for measuring torque in a motor vehicle gearbox

Info

Publication number: WO2017101926A1
Application number: PCT/DE2016/200544
Authority: WO
Inventors: Jürgen GIERL; Reinhard Stehr; Andreas Englisch
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2015-12-14
Filing date: 2016-11-24
Publication date: 2017-06-22
Also published as: DE102015225102A1; DE112016005709A5

Abstract

The invention relates to a gearbox (1) for a motor vehicle, which comprises a torque transmission device (2) with a spherical or convex outer contour (3), and a torque-sensing region (5) to which a torque-detecting device (6) is secured which is provided to generate an electrical signal that is dependent on the torque-dependent torsion and/or strain and allows the torque value to be inferred, said torque-sensing region (5) having a spherical and/or convex outer contour on which said torque-detecting device (6) is mounted directly.

Description

Transmission with directly applied torque detection device and

Method for torque measurement in a motor vehicle transmission

The invention relates to a transmission for a motor vehicle, such as a car, a truck or other commercial vehicle, with a torque transmitting device having a convex or convex outer contour and a torque sensing area, on which a torque detecting device is mounted, which is prepared in response to a torque-dependent torsion and / or stretching to generate an electrical signal that allows conclusions about the torque.

The invention thus relates to an arrangement for measuring an applied torque in a (automotive) transmission, such as in a CVT (continuously variable transmission) gear, during operation and a method for producing such an arrangement for controlling the contact forces of pulley sets of a (CVT) transmission.

Although torque measurements in passenger car transmissions are known, they are normally only made possible by devices mounted outside the transmission housing. In this case, hydraulic-mechanical measuring methods are usually used. Technically conceivable so far are measurements based on optical or

magnetoreactive principles and by glued strain gauges. Another possibility is to estimate the torque from the engine characteristics. However, all these known torque measurements have significant disadvantages. For example, glued strain gauges are suboptimal because they are subject to severe aging. Adhesives and carrier films age in operation when exposed to media and temperatures for a longer period of time, such as commonly found in gearboxes. Rather, conventional glued strain gauges (DMS) are designed for a short service life only. In addition, polymer materials tend to creep, causing the measuring sensitivity of the strain gage is reduced and the measuring signal can drift over a longer period of time.

Unfortunately, a hydraulically-mechanical torque sensor, which has hitherto provided very good results, unfortunately requires a relatively large amount of axial space. Its costs are also relatively high. Ultimately, this results in a hydraulic concept deviating strongly from the market standard, which is not necessarily accepted. Especially for transmissions in motor vehicles, especially for CVT transmission, but an improvement should be made possible. CVT transmissions, ie infinitely variable transmissions, today use the engine torque signal (MMI) for torque-adjusted adaptation, which is very inaccurate, especially in the new European driving cycle in the area of the partial load. However, since the partial load is very dominant in this new European driving cycle, large deviations between the MMI and the real transmission input torque can occur. These deviations can be up to about 100%, for example with an applied transmission input torque of about 50 numbers. However, the overpressure due to this uncertainty degrades the overall efficiency, unnecessarily increases the pump power consumption and expresses itself in greatly increased costs. Other measuring methods, such as those based on magnetic measurement principles, are disqualified, as a result of occurring metallic abrasion in the transmission, a measurement based on such magnetic measurement principles is usually not possible. Adjacent state of the art is also known from DE 10 2013 204 924 A1. There is disclosed an arrangement for determining a torque acting on a shaft, in particular a steering shaft. A steering wheel side first steering shaft section, a steering gear side second steering shaft section, and a torsion section connecting the steering shaft sections are used. The torsion section has a strain-sensitive direct coating with the structure of a strain gauge. It is therefore the object of the present invention to eliminate or at least mitigate the disadvantages of the prior art and to enable a more precise torque detection at a lower cost and over a long service life in transmissions of motor vehicles.

This object is achieved in a generic device according to the invention in that the torque sensing has a convex and / or convex outer contour to which the torque detecting device directly applied / attached / in particular coated, for example, is vapor-deposited.

The torque measuring device on which the invention is based is therefore placed directly in the gearbox housing on the input or output shaft. The measurement principle is carried out based expansion and is, for example, by means of a strain-sensitive coating. Known under the name "Sensotect ^®" made possible. The sensor layer may be coated directly on the drive or output shaft, such as in the documents

DE 10 2013 204 924 A1 and DE 10 2012 208 492 A1. Alternatively, the reaction within a measuring sleeve material fit in or on the transmission shaft is possible. The invention enables a torque measurement with very high accuracy and at the same time strong robustness without loss of space. The invention can also be used in couplings to adjust the contact pressure.

Advantageous embodiments are also claimed in the subclaims and are explained in more detail below. Thus, it is advantageous if the torque sensing area is formed as an integral, one-material and / or one-piece section of a transmission input shaft or a transmission output shaft, or is provided on the surface side by such a section. The application of the sensing element can, for example, be sustainably achieved by a vapor deposition process. For example, PVD and PACVD methods are suitable for this purpose. Particularly durable transmissions can then be obtained, which even at the end of the life still provide precise torque information. Alternatively, it is also possible for the torque-sensing area to be designed or set as a (originally) separate component from the transmission input shaft or the transmission output shaft. This simplifies the manufacturing process by allowing separate components to be stocked, which in turn have been coated with a PVD or PACVD process, with the finished separate components only having to be attached to the transmission input shaft or the transmission output shaft. In this case, the attachment is possible such that the torque is still completely / largely / partially through the transmission input shaft or the transmission output shaft, and the separate component transmits only such a small amount of torque that is sufficient that a distortion occurs, the conclusions on the entire Torque allows.

It has proven to be advantageous if the separate component is formed as an intermediate piece of the torque transmission device, or is designed as a torque transmitting device at least partially or in sections or in a certain length completely enveloping Einhüllbauteil. The Einhüllbauteil can then be kept in large numbers and edited so that it is easy and quick to install.

In this context, it has also proved to be advantageous if the intermediate piece or the Einhüllbauteil is designed as a sleeve, such as a metal sleeve. Space-saving use with low costs can then be ensured.

If the example. Onion-like or

torque transmitting device extending sleeve has a vollzylin- such or hollow cylinder-like expression / configuration, so the sleeve can be produced efficiently.

It has proven useful if the torque detecting device has an inner or outer diameter of 5 mm to 100 mm. If the torque detecting device has a layer structure of one or more layers, which is between 0.01 μιτι to 100 μιτι high, so a sufficiently high quality signal can be delivered.

An advantageous embodiment is also characterized in that the sleeve is frontally attached to a first attachment region, such as a front side or an outer surface of the torque transmitting device form, force and / or material fit, such as welded, for example. Via a circumferential or planar seam through laser beam welding.

The invention ultimately also relates to such a transmission, which is designed as a continuously variable transmission, such as in the manner of a CVT transmission. In other words, the torque measurement by a Sensotect ^® is -

Direct coating, i. a strain-sensitive direct coating having the structure of a strain gauge, on the transmission shafts or a torque measuring device comprising / consisting of a torsion, which also as

Einhüllbauteil or external socket can be called, namely the so-called measuring element realized. On the measuring element, or the gear shaft, an insulating layer, for example. Of aluminum oxide, applied, on which a deformation-sensitive layer (or layers) is located as a measuring layer. The insulating layer comprises, for example, an oxide, such as Al 2 O 3 and SiO 2 or nitrides, for example AlN. The insulation layer can be produced, for example, in the PVD (Physical Vapor Deposition) or PACVD (Chemical Assisted Physical Vapor Deposition) method. The measurement layer, which is located on the insulating layer is, for example, by a nickel alloy, in particular formed a nickel-chromium alloy, or of a Al _x Ga As _-x (semiconductor) formed / constructed. The strain sensitive coating can in turn be made by the PVD or PACVD process.

The measuring layer is structured similarly to known strain gauges / strain gauges. The structuring of the strain-sensitive direct coating with the Structure of a strain gauge takes place only after application of the coating on the measuring element or the transmission shaft (preferably by laser).

In a preferred embodiment, an organic or inorganic protective layer against environmental influences is applied to the measuring layer. The total thickness of the deformation-sensitive direct coating without the protective layer is preferably not more than about 4 μιτι, about 12 μιτι or about 20 μιτι. In particular, layer thicknesses of about 5 μιτι, about 10 μιτι and about 20 μιτι have been proven. The laser-processed strain-sensitive direct coating with the structure of a strain gauge has, in an advantageous embodiment, a strip structure, which are inclined to the axis of rotation by preferably approximately 45 °. Here, a layer is processed directly, which is not only arranged in a plane, but represents a spatial structure.

The bore of a torsion sleeve, which can also be referred to as Einhüllbauteil or outer sleeve is performed with ease to the shaft diameter. The finished torsion sleeve is pushed onto the shaft or an area of the drive shaft machined as a sleeve seat and joined directly to the shaft or sleeve seat by means of a welding process (eg a laser welding process, a friction welding process or a resistance welding process) or a soldering process, so that the torsion the shaft is transmitted to the torsion, the measuring element. Alternatively, the sleeve can be filled with ribs, which make it possible to press the torsion sleeve onto / into a (hollow) shaft and fix it in a material-locking manner according to a particular embodiment.

In addition to a strain-sensitive direct coating having the structure of a strain gauge, there is a signal transmission component on the torsion sleeve which cooperates with another stationary signal transmission component. The signal transmission can also be spent on the shaft / attached. It is a wireless, for example inductive signal transmission between the Torsionshülse or shaft, the rotor and a non-rotating component, such as the stator provided.

Including the entire assembly and connection technology as well as energy and signal transmission technology, the entire torque measuring device is extremely space-saving. By providing such a transmission with torque measuring device according to the invention an improved contact pressure is achieved with continuously variable transmissions, which makes itself felt positively in consumption. The invention will be explained in more detail with the aid of a drawing. Show it:

1 shows a longitudinal section through a section of a transmission according to the invention according to a first embodiment, Fig. 2 shows a second embodiment in a comparable to FIG. 1 representation, and

3 shows a further embodiment in a manner comparable to that of FIG. 1. The figures are merely schematic in nature and are only for the understanding of the invention. The same elements are provided with the same reference numerals.

Features of the individual embodiments may be partially interchanged. In Fig. 1, a portion of a transmission 1 according to the invention is shown. The transmission 1 is intended for use in a motor vehicle, such as a passenger car, a truck or another commercial vehicle, namely in a drive train. It has a torque transmission device 2. The torque transmission device 2 has a convex or convex outer contour 3. In particular, the torque transmission device 2 is designed in the manner of a shaft 4. It has a torque sensing area 5. On this torque sensing area 5, a torque detecting device 6 is provided. By means of this torque sungsvorrichtung 6, an electrical signal is generated in response to a torque-dependent torsion and / or elongation. This signal is sent to an evaluation element, not shown. This means are used, which are also not shown. In particular, inductively operating principles can be used.

The torque sensing area 5 itself also has a convex and / or convex outer contour. In particular, it has a cylindrical outer contour. The torque detecting device 6 is coated directly on the torque sensing portion 5. In particular, it is vapor-deposited or sputtered.

In the embodiment according to FIG. 1, the torque transmission device 2 is designed in the manner of a shaft 4, namely as a transmission input shaft 7 or a transmission output shaft 8.

Such an embodiment is also shown in FIGS. 2 and 3, but there are differences found. Thus, the torque sensing region 5 is provided by a separate component 9 from the transmission input shaft 7 or the transmission output shaft 8. In this point, the embodiments of FIGS. 2 and 3.

However, they differ again in that in the embodiment shown in FIG. 3, the separate component 9 is formed as an intermediate piece 10, whereas it is formed in the embodiment of FIG. 2 as an outer sleeve 1 1. The intermediate piece 10 is designed as a sleeve and fastened in a region near the end face via a weld seam 13 in each case at the remainder of the torque transmission device 2. Such a weld 13 has the outer bushing 1 1 in the region of flange ends 14. The weld should be on the outside. It should be noted that the outer sleeve flange ends may have, but not necessarily possess. It can also be introduced a depression in the shaft. Between the outer contour 3 of the torque transmission device 2 and an inner side 15 of the outer bush 11, a gap 16 or a spacing may be present between the flange ends 14. On the outer sleeve 1 1 and the sleeve 12 is outside the Drehmonnenterfas- sungsvorrichtung 6, applied in the manner of a coating or vapor deposition. The torque detecting device 6 may consist of several layers. In particular, the structure offers an insulating layer, an electrically conductive layer and a protective layer. It is also possible to use a plurality of electrically conductive layers.

Reference number list gear

Torque transfer device

Outer contour of the torque transmission device shaft

Torque sensing region

Torque detection device

Transmission input shaft

Transmission output shaft

separate component

connecting piece

outer bush

shell

Weld

flanging

inside

gap

Claims

claims

1 . Transmission (1) for a motor vehicle with a torque transmission device (2) with a convex or convex outer contour (3) and a

Torque Sensing (5) on which a torque detecting device (6) is mounted, which is prepared depending on the torque-dependent torsion and / or strain to generate an electrical signal that allows conclusions about the torque, characterized in that the torque sensing region (5) has a convex and / or convex outer contour, to which the torque detecting device (6) is applied directly.

2. Transmission (1) according to claim 1, characterized in that the

Torque Sensing Range (5) as an integral / einmaterialiger and / or one-piece portion of a transmission input shaft (7) or a transmission output shaft (8) is formed.

3. Transmission (1) according to claim 1, characterized in that the

Torque Sensing range (5) is designed or set as one of the transmission input shaft (7) or the transmission output shaft (8) originally separate component (9).

4. gear (1) according to claim 3, characterized in that the separate component (9) as an intermediate piece (10) of the torque transmitting device (2) is formed or as a torque transmitting device (2) at least partially or in sections or in a certain length completely sheathing Einhüllbauteil (1 1) is formed.

5. Transmission (1) according to claim 4, characterized in that the intermediate piece (10) or the Einhüllbauteil (1 1) is formed as a sleeve (12).

6. gearbox (1) according to claim 5, characterized in that the sleeve (12) has a full cylinder-like or hollow-cylinder-like expression.

7. transmission (1) according to one of claims 1 to 6, characterized in that the torque detecting device (6) has an inner or outer diameter of about 5 mm to about 100 mm.

8. gearbox (1) according to one of claims 1 to 7, characterized in that the torque detecting device (5) has a layer structure of an insulating layer and a deformation-sensitive measuring layer.

9. gearbox (1) according to one of claims 1 to 8, characterized in that the torque detecting device (5) has a layer structure of a deformation-sensitive measuring layer, which was structured meandering after coating.

10. Transmission (1) according to one of claims 1 to 9, characterized in that an outer bushing (1 1) is attached to a first fastening region form, force and / or material fit.