DE102011010878A1 - Tip moment delimiter for hydraulic clutch actuator mounted in motor vehicle, has bypass port that is opened and closed respectively so that pressure of fluid flowing on transmitter side portion and receiver side portion is controlled - Google Patents

Abstract

The delimiter (1) has a throttle element (4) that is provided over the cup side portion (5) at the tip moment delimiter housing (13) which is filled with fluid. An aperture (7) is arranged in the cup bottom portion (6) of throttle element. A bypass port (8) for fluid flow is extended around the cup bottom portion of the throttle element. The pressure of fluid flowing on the transmitter side portion (2) and receiver side portion (3) is controlled in the opening and closed states of bypass port respectively.

Description

The invention relates to a Spitzenmomentbegrenzer for a hydraulic actuator, in particular for clutch actuation, for the separation of a friction clutch in the drive train of a motor vehicle according to the preamble of claim 1.

Such hydraulic actuators for disconnect couplings in the drive train of a motor vehicle are well known. They consist of a master cylinder, which can be acted upon by a clutch pedal. From this master cylinder, a hydraulic line leads to a slave cylinder, which in turn actuates a clutch via a release mechanism. The torque load that is applied to the drive train of the vehicle during the actuation of such a disconnect clutch depends inter alia on the speed of the engagement process. In extreme driving, but also accidentally slipping off the foot of the clutch pedal, extremely high torques can occur, which can damage the drive train and lead to costly repairs.

It is therefore known to integrate in the hydraulic line between the master cylinder and the slave a Spitzenmomentbegrenzer, which causes a higher flow resistance in the hydraulic line when exceeding a predetermined engagement speed and thus limits the engagement speed. In this case, such Spitzenmomentbegrenzer be carried out automatically, for example by a diaphragm is displaced by friction of the hydraulic fluid above a certain flow rate against a bias and narrows a flow opening. Such a Spitzenmomentbegrenzer is for example in the DE 10 2005 021 743 described.

In addition, there are also Spitzenmomentbegrenzer that can be switched on and off via an external circuit. An example of such a peak torque limiter is in DE 10 2004 062 554 A1 shown.

A disadvantage of automatic top torque limiters is that a quick engagement depending on the driving situation is not necessarily a threat to the transmission and powertrain.

For example, in a gear change in higher gears at higher speeds, only comparatively small torques occur even during quick engagement. When using a Spitzenmomentbegrenzers in these driving situations is thus engaged slower than necessary, causing the clutch grinding unnecessarily long. In these driving situations, therefore, the use of an active peak torque limiter no safety gain, but increases the clutch wear and the energy consumption of the clutch.

As a remedy, the switchable peak moment limiters already mentioned above have been developed. With these, there is the possibility to turn on or off the throttle function of the peak torque limiter as needed.

The Indian DE 10 2004 062 554 A1 shown Spitzenmomentbegrenzer in this case has a slidable diaphragm, which is held by a bias by a spring spaced from a seal. In this case, the diaphragm has bypass channels, which together with an aperture for a low flow resistance. When the throttle function is to be used, the diaphragm made of a ferromagnetic material is pulled against the gasket by means of a magnetic field generated by an electric coil, so that the bypass channels are closed and the flow resistance greatly increases. In this case, a considerable amount of electrical energy is necessary for closing and closing, since the spring tension of the biasing spring must be permanently overprinted by the magnetic force when the Spitzenmomentbegrenzer is closed. The necessary holding force is even increased if, during the return flow, the force is rectified by the pressure drop with the biasing force of the spring and thus the throttle diaphragm is pushed away even more from the sealing seat. Conversely, the pressure drop at the Spitzenmomentbegrenzerblende in the closed state in the fluid flow in the direction of flow of the diaphragm to an additional holding force that must be overcome when opening the aperture. It is therefore necessary to make the biasing spring relatively strong in order to allow opening of the Spitzenmomentbegrenzers also against the fluid flow. If the preload force is too low, it may no longer be possible to open the peak moment limiter during fluid flow. On the other hand, however, a high biasing force increases the energy requirement of the electric coil, so a tradeoff must be found between the ability to open the Spitzenmomentbegrenzer in all operating conditions, and the energy consumption of the entire arrangement.

In addition, the opening speed of the fluid flow is influenced by the biasing force. If the preload force is only slightly above the pressure force by the pressure drop at the Spitzenmomentbegrenzerblende, the switching operation will be relatively slow.

It is therefore an object to provide a Spitzenmomentbegrenzer available, which is switchable in response to operating conditions of the motor vehicle, has a low energy consumption and ensures rapid switching regardless of a fluid flow through the hydraulic system.

The solution of this problem is achieved with a Spitzenmomentbegrenzer according to claim 1. Advantageous developments emerge from the dependent claims.

A peak torque limiter according to the invention has a fluid passage which has a flow resistance which is considerably larger than the hydraulic line. In addition to this passage, there are one or more additional bypass openings in the peak torque limiter, which greatly reduce the flow resistance of the peak torque limiter when the peak torque limiter is open. Within the peak moment limiter is a movable closure element which closes the bypass opening in a closed position and thus increases the flow resistance of the peak moment limiter and releases the bypass opening (EN) in an open position and lowers the flow resistance of the peak moment limiter. In this case, the closure element is designed so that in the closed position by the pressure drop acting on the closure element pressure forces to the direction of movement of the closure element during the opening or closing operation are arranged substantially vertically. Thus, no force caused by the pressure drop must be overcome to open or close the peak torque limiter. Likewise, when closed, it is not necessary to over-pressurize a restoring force caused by the fluid flow to maintain the closure member in the closed position.

Thus, on the one hand, the energy demand of the peak torque limiter can be considerably reduced and on the other hand, a fast switching function independent of the fluid flow through the peak torque limiter can be guaranteed.

Further advantages, features, feature combinations and features of the invention will become apparent from the description of an embodiment of the invention and by the drawings.

These show:

1 a section through a Spitzenmomentbegrenzer invention.

1 shows a Spitzenmomentbegrenzer invention 1 with a sensor-side connection 2 and a subscriber-side connection 3 , By means of these connections 2 . 3 is the top torque limiter 1 integrated into the hydraulic line (not shown). Inside the peak torque limiter 1 there is a throttle element 4 which has a cup-shaped form. In this case, the throttle element is supported 4 over the mug sides 5 on the Spitzenmomentbegrenzergehäuse 13 from. In the cup bottom 6 is a shutter 7 arranged, which has a significantly reduced compared to the hydraulic line diameter and thus a significantly increased flow resistance. The bypass openings 8th extend around the cup bottom area 6 the throttle element 4 to the side wall 5 the throttle element 4 , the corresponding congruent openings or slots 14 has, through which when open Spitzenmomentbegrenzer 1 can also pass hydraulic fluid. Alternatively, of course, the bypass openings 8th be extended so that they pass over the side wall 5 the cup-shaped throttle element 4 are extended so that no openings in the side wall 5 the throttle element 4 necessary. Also other forms of throttle element 4 For example, a disc-shaped aperture with correspondingly laterally arranged bypass openings or additional, closable aperture openings in the diaphragm, depending on the embodiment conceivable.

In addition to the throttle element 4 there is a closure element with a magnetic ring 10 and a sealing cylinder 9 , The sealing cylinder 9 extends through the magnetic ring 10 and has a contact area 16 for sealing pressing on the cup bottom 6 the throttle element 4 on. Here are the outer sides of the sealing cylinder 9 on sealing lips 15 of the Spitzenmomentbegrenzergehäuses to such the bypass openings 8th seal tightly.

In the closed position, as in 1 shown, arises during the fluid flow through the Spitzenmomentbegrenzer a pressure drop, which essentially at the aperture in the throttle element - cup bottom 6 occurs. On the donor side 2 of the peak torque limiter 1 Then there is the pressure P _a , while on the slave side 3 of the peak torque limiter 1 the pressure P _b prevails. Because the side surfaces 17 and 18 of the closure element have substantially the same area, and the pressure P _a applied to these surfaces is constant on the entire closure element, the pressure forces applied in or against the direction of movement of the closure element on the closure element are respectively of the same amount, but opposite, so that they cancel out almost completely. Thus, the closure element can also be at fluid flow taking place with P _a > P _b and the resulting pressure drop at the throttle element 4 be moved from the closed to the open position, without requiring a strong pressure force from the pressure drop .DELTA.P (= P _a - P _b ) must be overcome. Conversely, even when the closure is closed and the opposite fluid flow (P _a <P _b ) is taking place, there is no restoring force greatly increased by the pressure drop on the closure element towards the open position, so that there is no increased force for securely holding the closure element on the throttle element 4 necessary is.

To generate a restoring force on the closure element is in Spitzenmomentbegrenzer 1 a metal plate 12 arranged in the interior of the peak torque limiter 1 on the throttle element 4 opposite side near the encoder connection 2 located. Because the magnetic ring 9 is designed as a permanent magnet, arises between the sub-plate 12 , which is made of a ferromagnetic material, and the magnetic ring, a magnetic attraction, the closure element in an open position on the left interior edge of the Spitzenmomentbegrenzers 1 emotional. Of course, different embodiments for the generation of the restoring force, for example with a spring or with two separate coils possible.

For switching the closure element in the closed position, the Spilzenmomentbegrenzer 1 a coil 11 on, for example, in Spitzenmomentbegrenzergehäuse 13 can be poured. Alternatively, it is also possible to use the coil 11 subsequently at the peak torque limiter housing 13 to arrange and fasten. If now an electrical voltage on the coil 11 is applied, results in an electric current through the coil windings and a magnetic field is inside the coil 11 generated. By appropriate polarity of the permanent magnet in the magnetic ring 10 the closure element becomes a magnetic force on the magnetic ring 10 generates the attraction between magnetic ring 10 and metal plate 12 directed against. When this magnetic force is the attraction force between magnetic ring 10 and metal plate 12 exceeds, the closure element from the metal plate away toward the throttle element 4 moves until the sealing cylinder 9 in the seal seat on the cup bottom 6 the throttle element 4 comes to the plant and the bypass openings 8th closes, leaving the top torque limiter 1 is in its throttle position. As already mentioned above, this switching process can be due to the pressure conditions in Spitzenmomentbegrenzergehäuse 13 even when caused by fluid flow pressure drop at the throttle element 4 take place without overcoming a large pressure force, so that the switching capability and the switching speed regardless of the currently existing pressure conditions in the peak torque limiter 1 is and a switching operation can take place at any time.

LIST OF REFERENCE NUMBERS

1

peak torque

2

geberseitiger connection

3

slave side connection

4

throttle element

5

side walls

6

cup base

7

aperture

8th

bypass ports

9

sealing cylinder

10

magnetic ring

11

Kitchen sink

12

metal plate

13

Spitzenmomentbegrenzergehäuse / Housing

14

Sidewall openings

15

sealing lips

16

Sealing cylinder edge

17

Side surface closure element

18

Side surface closure element

P _a

Peak torque internal pressure

P _b

Peak torque internal pressure

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005021743 [0003]
• DE 102004062554 A1 [0004, 0008]

Claims (7)

Peak torque limiter ( 1 ) for a hydraulic line, in particular for use in a hydraulic system for actuating a clutch for a motor vehicle, having a housing ( 13 ) and a passage ( 7 ), which has a relation to the hydraulic line considerably increased flow resistance, wherein the housing ( 13 ) is filled in operation with a fluid and at least one bypass opening ( 8th ), which is adapted to provide an additional way for a fluid flow, wherein the bypass opening ( 8th ) and the passage ( 7 ) in the addition have a flow resistance which is in the range of the flow resistance of the hydraulic line, and a closure element in the peak moment limiter ( 1 ) is provided, which is adapted by means of a movement of switching elements, the bypass opening ( 8th ), wherein the closure element can be controlled by means of a switch, switching element or a control to the bypass opening ( 8th ), and when closed, a pressure drop at the peak moment limiter ( 1 ), from which compressive forces result, characterized in that the pressure forces acting on the closure element in the closed state are directed in such a way that the force components in the direction of movement of the closure element when opening or closing the bypass opening ( 8th ) substantially cancel. Peak torque limiter ( 1 ) according to claim 1, characterized in that the closure element is at least partially formed of a magnetic or magnetizable material. Peak torque limiter ( 1 ) according to claim 2, characterized in that a coil ( 11 ) for generating a magnetic force on the closure element by means of a current flow in or on the peak moment limiter ( 1 ), whereby the current flow through the coil ( 11 ) can be switched on or off by means of a controller. Peak torque limiter ( 1 ) according to claim 2 or 3, characterized in that a magnetic or ferromagnetic element ( 12 ) for generating a bias on the closure element in the peak moment limiter ( 1 ) is arranged. Peak torque limiter ( 1 ) according to claim 3, characterized in that a further coil for generating a magnetic force by means of a current flow to the closure element in or on the Spitzenmomentbegrenzer ( 1 ), wherein the current flow through one or both coils by means of a control for moving the closure element in the closed and / or open position of the bypass opening ( 8th ) is changeable. Peak torque limiter ( 1 ) according to one of the preceding claims, characterized in that the peak torque limiter ( 1 ) an aperture ( 6 ) with an opening ( 7 ), wherein the opening diameter is smaller than the diameter of the hydraulic line, and to the aperture ( 6 ) at least one bypass opening ( 8th ) is trained. Peak torque limiter ( 1 ) according to one of the preceding claims, characterized in that the closure element is a sealing cylinder ( 9 ), one end of which ( 16 ) for pressing against the diaphragm ( 6 ) is formed, wherein with the pressing of the closure element to the panel ( 6 ) the bypass opening ( 8th ) through the sealing cylinder ( 9 ) is closed.

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