DE112014002362B4 - Sensor system with integrated guide and anti-twist device in a hydraulic clutch release mechanism - Google Patents

Abstract

Clutch release device (1) of the hydraulic type, for a clutch, having a piston (2) designed to reduce a pressure chamber (7), which is in operative connection with a release bearing (12), wherein a displacement measuring system is provided for sensing the axial position of the piston (2) is designed, one of a Wegmesssensor (18) to be sensed target (16) is provided, the at least axial forces from the piston (2) receiving and axially along the Wegmesssensor (18) arranged along, the Wegmesssensor (18) geometrically adapted to the non-rotatably attached to the piston (2) target (16) is adapted that rotation of the target (16) is excluded relative to the Wegmesssensor (18) via a positive connection, the outer diameter of the target (16) on a by the Wegmesssensor (18 ), wherein the displacement sensor (18) has a coil (20) which is provided on a central passage having a core (19) whose inner diameter the outer diameter of the Sensierraums (17) defined, characterized in that the core (19) is constructed of a material suitable for a sliding bearing material or comprises, the target (16) comprises a non-magnetic material or the target (16) is constructed therefrom andthe target (16) is attached to a linkage (13) in a positive, force and / or material fit, which is fixed directly or indirectly axially and / or rotationally fixed to a bearing inner ring (11) of the release bearing (12).

Description

The invention relates to a clutch release of the hydraulic type, for a clutch, such as a dry or wet running clutch, for example. A dual clutch of a car or a truck, with a designed to reduce a pressure chamber piston in which hydraulic fluid is compressible, the piston force-transmitting is operatively associated with a release bearing, further wherein a Wegmesssystem is provided, which is designed to sense the axial position of the piston, wherein there is further provided by a Wegmesssensor to be sensed target, at least axial forces from the piston receiving and axially along the Wegmesssensor is arranged along.

The invention is in the field of disengagement systems, in particular central clutch release (CSC, i.e. concentric slave cylinder) housings. It is used in the sensing of the Ausrückweges.

Normally, so-called PLCD systems, ie permanent magnetic linear contactless displacement sensor systems using magnetic targets are used. However, a standard PLCD must be divided into a receiver coil part and an electronic part because of the high temperatures in this range. The CSC, ie the central clutch release device must then have an anti-rotation, so that the magnet is always exactly below or directly next to the sensitive element is guided, i. that the rotational association between the magnet and the sensor remains unchanged.

PLCD displacement sensors consist essentially of a special core made of soft magnetic material, which is wound over its entire length by a coil, such as a primary coil and at the ends each have a further, preferably short evaluation coil. A permanent magnet approximated to the sensor leads to a local magnetic saturation and thus to a virtual division of the core. If the primary coil is occupied with a suitable alternating current, a voltage dependent on the position of the saturated region is induced in the evaluation coils. Thus, the length of the virtual parts of the core and thus the position of the saturated region can be determined.

The supply of the sensor with a suitable alternating current and the processing, evaluation and conversion of the signals is often done by an external electronic module or by an integrated electronics in the sensor. At the output of the electronic circuit is a linearly dependent on the location of the magnet signal, z. B. at a current interface of 4 to 20 mA or a voltage interface of 0 to 5 V or 10 V available.

To prevent measurement errors, the magnet must be accurate and repeatable, i. especially free of play, are guided to Wegmesssensor. This usually requires a rotation lock. Also previously expensive magnetic guide slide are necessary. This often entails high costs. Even the use of a magnet as a target is relatively expensive.

Position measuring systems for clutch release systems are basically already out of the DE 10 2008 057 644 A1 known. There, a displacement measuring system for clutch release systems with a movable component assignable magnetic element is disclosed, which is provided with a sensor electronics having sensor system which is arranged on a fixed component in the form of a housing of the piston-cylinder system. The sensor system is in operative connection with the magnetic element and the sensor electronics of the sensor system is arranged in a recess integrated in the housing.

These alternative solutions are also from the DE 20 2006 014 024 U1 known, there is disclosed a Zentralausrücker for a hydraulic clutch actuation. The Zentralausrücker, with a cylindrical through-bore housing and a concentrically disposed within the through hole and centered at one end of the housing attached to the housing tubular sleeve has an annular piston which is engageable axially movably engageable with the clutch in operative connection. At the outer end of the annular piston, an inner ring of a release bearing is fixed, wherein a sensor for detecting the axial position of the annular piston is fixed relative to the housing stationary on the housing, and wherein the sensor is associated with an axially displaceable and guided magnetic body, with one on the inner ring fastened ring body for driving with the piston at its axial displacements is connected axially free of play, wherein the magnetic body is guided displaceable over its displacement constant distance to the sensor on the housing and with a guide shoe in a circumferential groove of the annular body axially free but radially movable engages.

From the DE 100 18 677 A1 Further, such a solution is known in which a target is displaced axially relative to a sensor.

From the DE 10 2005 049 056 A1 the sensor arrangement is coaxially introduced with respect to the axis of rotation of the coupling in the actuating system.

This object is achieved by the features of the claim.

The displacement sensor is geometrically adapted to the non-rotatably mounted by the piston target that rotation of the target is excluded relative to the displacement sensor via a positive connection.

In other words, to reduce costs and simplify assembly in a CSC, a sensor is provided with a plunger coil and a target inserted therein, the target being secured to the plunger while serving as a rotation safeguard.

Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

Thus, it is advantageous if the target is arranged and / or designed for immersion in the distance measuring sensor. A diving coil-like configuration can then be easily realized. A striking of the target in the interior of the displacement sensor ensures positive locking and then efficiently prevents a rotation of the target / piston to the displacement sensor.

According to the invention, the outer diameter of the target is adapted to a sensing space enclosed by the distance measuring sensor, so on the one hand immersion of the target in the interior of the displacement measuring sensor can be achieved / achieved and on the other hand the desired anti-twist protection can be achieved cost-effectively with mechanically loadable means.

According to the invention, the displacement sensor has a coil which is present on a core having a central passage whose inner diameter defines the outer diameter of the sensing space. A non-contact path measuring system can then be realized, the cost of such a system is kept low, because on the one hand, the assembly is easy and on the other hand, the individual components can be made low.

In order to ensure a low-wear operation over a long time, it is inventively provided that the core is constructed of a suitable material for a sliding bearing or includes this. Bronzelegierungen, eg. Using copper, white metal alloys, aluminum alloys, lead, plastic, such as particularly preferably PTFE, or ceramic have been found to be particularly suitable.

Expensive magnetic materials can be dispensed with, since according to the invention the target comprises or is constructed from a non-magnetic material.

In this context, it is advantageous if the target consists of an iron-containing material, is constructed as a steel sheet or transformer sheet, comprises μ-metal, amorphous metal or nano-crystalline metal and / or crystalline ferrite. With respect to μ-metal, soft magnetic nickel-iron alloys are recommended, especially those having a high magnetic permeability of μ _r in the range of about 50,000 to 140,000. In this way, a precise measurement can be expected.

The assembly of the individual components is simplified according to the invention, since the target is positively, force and / or materially attached to a linkage, which is directly or indirectly, for example, with the interposition of a separate driver, axially and rotationally fixed to a bearing inner ring of the release bearing ,

Long-term precision is also improved when the target is aligned and guided concentrically with the coil.

For further processing of the data provided by the distance measuring system, it is advantageous if the distance measuring sensor is connected to an evaluation electronics.

The insertion of a plunger coil for sensing has a number of advantages, such as the use of a plunger coil for sensing. that expensive magnets can be replaced by low-cost targets, that the target can be guided in the coil and thus at the same time forms a security against rotation, etc .. A very complex concept of the magnetic guide, as it was previously used, can be achieved by a sliding bearing of the coil on the target or of the target on the coil can be avoided. In this case, the distance measuring sensor defines with its plastic material an inner diameter within which the target is guided as free of play as possible. The tolerances in the system can be increased, thereby improving the guidance accuracy. Tilting, twisting, and / or a shift in the concentricity of the target within the distance measuring sensor then has no influence on the measuring accuracy.

The elimination of the magnet, the sensor system can be used even at very high temperatures, with only the coil wire insulation is to be regarded as limiting, since it begins to melt at certain temperatures. Were expected at high temperatures expected particularly high magnetic costs, this can now be ruled out. Also can on the frequently used rare earth magnets are dispensed with, even in a tense construction space situation, which minimizes costs.

It should be noted that the target in the bobbin is feasible. However, a target end can be designed so that a direct connection to the release bearing is possible, in particular under backlash in the axial direction. The shape of the target end then has no influence on the measurement, in particular if it is arranged axially outside the measuring coil. In this way, a Linearwegmessung be made. The highly accurate guidance of the magnet relative to the sensor chip can be omitted. The target material does not have to be made of high-quality magnetic material, but can consist of so-called transformer sheet metal. A bobbin of the displacement sensor and the target simultaneously form the anti-rotation. In this way, an LVDT (Linear Variable Differential Transformer) can be replaced. Also Verdrehverhindernde dowel pins are no longer necessary.

The invention will be explained in more detail with the aid of a drawing. Therein is shown a first embodiment.

The only figure 1 shows a Kupplungsausrücker invention 1 ,

The clutch release 1 is a hydrostatic clutch release (CSC) designed for use on a clutch assembly such as a dual clutch. The clutch may be a dry-running clutch or a wet-running clutch. It can be used on cars or trucks.

A piston 2 , in the manner of an annular piston, is along a guide sleeve 3 , in the manner of a cylinder, in the direction of a longitudinal axis 4 axially slidably mounted. At a first end 5 of the piston 2 is a seal 6 present, a pressure room 7 seals. The pressure room 7 is supplied with hydraulic fluid, such as oil. The oil is at reduction of the pressure space 7 pressurizable. Was the pressure in the pressure chamber 7 increases, so is a displacement of the piston / ring piston 2 in the direction of the longitudinal axis 4 , from a flange area 8th the guide sleeve 3 and a sealing element arranged there 9 forced away.

At one the first end 5 opposite second end 10 of the piston / ring piston 2 is with the interposition of one or more other components, a bearing inner ring 11 designed as a rolling bearing release bearing 12 at least axially fixed. Usually the bearing inner ring 11 also rotatably on the piston 2 appropriate.

A linkage 13 has a driver 14 and a coupling piece 15 on. The driver 14 and the coupling piece 15 are positively, positively and / or materially connected to each other, in the present embodiment, these two components form an integral (one-piece) and one-piece molded element. The driver 14 is force, positive and / or cohesive with the bearing inner ring 11 connectable.

At the coupling piece 15 is a target 16 attached. The target 16 can in a Sensierraum 17 a displacement sensor 18 penetration. The target 16 is made of sheet steel, transformer sheet metal or other non-magnetic material. In particular, μ-metal, amorphous metal or nano-crystalline metal has been found to be advantageous. Soft magnetic nickel-iron alloys with a high magnetic permeability of 70,000 to 120,000, in particular 100,000 are advantageous here.

The distance measuring sensor 18 has a suitable material for plain bearings as a core 19 on. The core 19 acts as a guide for the target 16 , The core 19 is surrounded by wire windings, which is a coil 20 molding. The distance measuring sensor 18 is part of a position measuring system.

Regarding the mode of action, it should be stated that during movement of the piston 2 along the longitudinal axis 4 a movement of the bearing inner ring in the same direction 11 is forced and thereby directed in the same direction movement of the driver 14 , the coupling piece 15 and thereby the target 16 is enforced. The target 16 then dive into the Sensierraum 17 one, reducing the relative position of the target 16 through the distance measuring sensor 18 can be determined. This allows conclusions about the position of the piston 2 pull. The further the target 16 in the Sensierraum 17 immersed, the closer is the first end 5 of the piston 2 the sealing element 9 ,

A feather 21 serves as a biasing element and may be formed as a helical spring, in particular as a compression coil spring.

LIST OF REFERENCE NUMBERS

1

clutch release

2

Piston / piston ring

3

Guide sleeve / cylinder

4

longitudinal axis

5

first end

6

poetry

7

pressure chamber

8th

flange

9

sealing element

10

second end

11

Bearing inner ring

12

release bearing

13

linkage

14

takeaway

15

coupling piece

16

target

17

Sensierraum

18

Displacement

19

core

20

Kitchen sink

21

feather

Claims (5)

Clutch release device (1) of the hydraulic type, for a clutch, with a piston (2) designed to reduce a pressure chamber (7), which is in operative connection with a release bearing (12), wherein a displacement measuring system is provided for sensing the axial position of the piston (2) is designed, one of a Wegmesssensor (18) to be sensed target (16) is provided, at least axial forces from the piston (2) receiving and axially along the Wegmesssensor (18) arranged along, the Wegmesssensor (18) geometrically adapted to the non-rotatably attached to the piston (2) target (16) is adapted that rotation of the target (16) is excluded relative to the Wegmesssensor (18) via a positive connection, the outer diameter of the target (16) on a by the Wegmesssensor (18 ), wherein the displacement sensor (18) has a coil (20) which is provided on a central passage having a core (19), the Innendurchme More specifically defined the outer diameter of the Sensierraums (17), characterized in that the core (19) is constructed of a material suitable for a sliding bearing material or includes, the target (16) comprises a non-magnetic material or the target (16) constructed therefrom is and the target (16) on a linkage (13) positively, positively and / or materially secured, which is directly or indirectly axially and / or rotationally fixed to a bearing inner ring (11) of the release bearing (12). Clutch release (1) to Claim 1 , characterized in that the target (16) for immersion in the Wegmesssensor (18) is arranged and / or designed. Clutch release (1) to Claim 1 , characterized in that the target (16) consists of a ferrous material, constructed as a steel sheet or transformer sheet, μ metal, amorphous metal, nano-crystalline metal and / or crystalline ferrite comprises. Clutch release (1) according to one of Claims 1 or 3 , characterized in that the target (16) is aligned and guided concentrically to the coil (20). Clutch release (1) according to one of Claims 1 to 4 , characterized in that the distance measuring sensor (18) is connected to an evaluation electronics.

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