WO2014139524A2

WO2014139524A2 - Actuating device for a clutch

Info

Publication number: WO2014139524A2
Application number: PCT/DE2014/200078
Authority: WO
Inventors: Christoph Raber; Sebastian Honselmann; Urban Panther; Barbara MICHEL
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2013-03-12
Filing date: 2014-02-24
Publication date: 2014-09-18
Also published as: DE112014001250B4; DE102014203271A1; CN105073215A; DE112014001250A5; WO2014139524A3; CN105073215B

Abstract

The invention relates to an actuating device for a clutch, particularly for motor vehicles, comprising a clutch pedal, which is operatively connected to a master cylinder having a piston movable along a first longitudinal axis. Upon actuation of the piston, the master cylinder, via a pressure line, provides an actuating pressure for actuating the clutch. According to the invention, the clutch pedal can actuate an actuating element having at least one curved path, and the piston of the master cylinder is operatively connected to the curved path of the actuating element and can be actuated by a variation of the curved path.

Description

Actuation device for a clutch

The invention relates to an actuating device, for example for a clutch, in particular for motor vehicles, according to the preamble of the first claim. Such controls are also used for brake pedals.

In a hydraulic actuation of a vehicle clutch in a motor vehicle, the clutch is actuated by means of a hydraulic slave cylinder, which is connected via a hydraulic pressure line to a master cylinder. A piston of the master cylinder is Ü over a foot pedal, which communicates with the master cylinder for example via a push or piston rod, acted upon. In these systems, the pedal force for actuating the foot pedal depends on the clutch characteristic, wherein different pedal forces occur over the actuating travel. The clutch characteristic and thus also the characteristic of the pedal force on the actuating travel can be z. B. change due to wear of the clutch.

In order to achieve a smooth as possible course of the actuating force on the pedal travel or to reduce the actuation force applied by the driver on the pedal lever when operating the clutch, different solutions are known from the prior art. In addition to various energy storage devices for adjusting the pedal force, there are also path-controlled mechanisms that function through work redistribution. For this purpose, a variant is known in which by scenes the force resultant is changed via the actuation and a cylinder with a variable cross-section. Both options redistribute the work in the system. In sum, it remains the same.

For example, DE 10 2008 061 569 A1 describes a clutch actuation system with a disengaging unit and an actuation unit actuated by an actuation unit for acting on the disengagement unit via a force transmission unit with a compensation device for achieving a predetermined actuation force characteristic. In connection with the use of the proposed compensating device, the use of a hydrostatic clutch release unit can be provided with a master cylinder connected to the actuator, which acts on a slave cylinder by means of a pressure line designed as a force transmission unit, wherein the actuating device is a clutch pedal which can be rotated about a pivot point. To compensate for force peaks and smoothing the force curve over the actuating travel is provided between the actuator and a housing-fixed support point, for example on the bulkhead of the vehicle body, a frame part or on the master cylinder housing directly a compensation device. The loading device is designed in the form of a master cylinder, a piston rod and a piston. The master cylinder has on its outer circumference at least one profile part, roll on the support members by means of the rollers. The piston rod, which acts on the piston and which is rotatably connected to the clutch pedal, is received on the same receptacle as the supporting parts.

Although such devices for adjusting the pedal force / actuating force can adjust the force curve. Power dispersions due to deviations of the actuating force, which arise for example by tolerances of the components, but they can not compensate. If large deviations are present, the adjusted force courses also scatter strongly. In addition, known adjustment mechanisms often provide no detection of the actuator in the new position.

Therefore, the object of the invention is to provide a hydraulic actuator for a clutch, in particular for motor vehicles, which allows a variable force operation and is adjustable.

This object is achieved with the features of the first claim. Advantageous embodiments emerge from the subclaims.

The actuating device for a clutch, in particular for motor vehicles, cooperates with a clutch pedal, which is operatively connected to a piston having a piston displaceable along a first longitudinal axis, wherein the master cylinder upon actuation of the piston via a pressure line provides an actuating pressure for the actuation of the clutch, and According to the invention with the clutch pedal, an actuating element is actuated, which has at least one trajectory, wherein the piston of the master cylinder is in operative connection with the trajectory of the actuating element and indirectly by actuation of the clutch pedal by a change in the trajectory of the actuating element is actuated. The piston of the master cylinder is thus not fixed as usual with its piston rod directly on the clutch pedal, but the clutch pedal acts indirectly on the actuator and its trajectory on the piston. This makes it possible to adjust the pedal force curve and compensate for differences in force of the pedal force acting.

The actuating element is displaceable along a displacement axis relative to the master cylinder, which is at an angle to the longitudinal axis of the master cylinder, wherein the master cylinder is preferably arranged at an angle of 90 ° inclined to the displacement axis of the actuating element. On the actuating element, a plurality of different cam tracks are preferably formed, which may each be assigned to one or more master cylinders.

The curved element preferably has on its surface distributed over the circumference different trajectories, wherein a plurality of pistons of a plurality of cylinders are in operative connection with the trajectories. The number of indirect cylinders can be chosen arbitrarily. The piston (s) in the trajectories may be guided by lateral guides on the actuator and / or on the master cylinder. By omitting the guides, the variance increases.

The piston of the master cylinder is acted upon in each case by the spring force of a spring in the direction of the actuating element and is applied to the trajectory, so that a continuous contact of the piston is ensured at the surface of the trajectory. Upon displacement of the actuating element along the displacement axis each piston is acted upon by the slope of the trajectory with a force acting in the direction of the longitudinal axis of the master cylinder against the spring force of the spring actuating force, which makes the displacement of the piston either easier or more difficult. So a variable Betätigungskraftverlauf can be achieved. Since this is a principle of redistribution of work, however, the total workload must remain the same.

In contrast to other force adjustment systems, the operating force curve can also be adjusted. A force deviation can be removed for this purpose, for example, hydraulically via the pressure in the pressure line or somewhere in the hydraulic system. It is, for example, an actuator can be provided, with which, when the pressure is exceeded, a rotation of the actuating element is realized about its displacement axis, so that other distributed over the circumference curved paths with the / the piston engage. In this case, there is a feedback of a necessary actuating force to the actuator, such that when the actuating force increases above a certain threshold, the actuator is changed over by the actuator of an active cam track, with which the piston is in operative connection to another active curved path.

The actuator is preferably formed in Firm a Nachstellkolbens, which is arranged between the pressure line and the actuating element and which acts on exceeding a predetermined pressure in the pressure line to the actuating element. Exceeds the pressure in the pressure line on the annular surface of the Nachstellkolbens in Nachstellzylinder the force of a counter-spring, which is coupled via a cable and a pulley to the adjuster, the actuator is rotated about its axis to a new curve. So that the adjustment does not turn back, a check valve is used, which is arranged between the pressure line and the adjusting cylinder. It opens only when pressure is exceeded and then allows the adjustment.

Alternatively, a sensor or exceeding a certain force, e.g.

Bearing force in combination with a mechanical or electrical mechanism take over the task of readjusting.

The invention allows numerous embodiments. To clarify its basic principle, a variant using the embodiment described below is shown

Show it:

Figure 1 is a schematic representation of an embodiment in the side view and Figure 2 in front view.

Figures 1 and 2 show a schematic representation of an embodiment of an actuating device according to the invention for a clutch, for example for a clutch a motor vehicle, which is operable in a conventional manner by a release system of a hydraulic transmission path.

The release system is acted upon by at least one master cylinder, in the example shown by a first master cylinder 1 and a second master cylinder 2, which are connected via a common pressure hose D having an output D1 with a slave cylinder, not shown, a release system. The first and the second master cylinder 1, 2 each have a piston 3, which is acted upon along a longitudinal axis A by a compression spring 4 in the direction of an actuating element 5. The actuating element 5 is displaceable along a displacement axis B upon actuation of the clutch pedal K and has on its surface distributed over the circumference here a total of six trajectories 6 (shown in FIG. 2). The first and the second master cylinder 1, 2 are arranged with their longitudinal axes A at an angle α - in each case 90 ° offset and thus at right angles to the displacement axis B of the actuating element 5. The two pistons 3 of the first and second master cylinders 1, which are arranged opposite one another, engage in two circumferentially offset by 180 ° and thus opposite to each other trajectories 6. From Figure 2 it can be seen that each trajectory 6 has two lateral guides 6.1, between which the piston 3 is guided. The compression springs 4 provide in the master cylinders 1, 2 for the contact of the piston 3 to the trajectory 6. Upon actuation of the clutch pedal K, the actuator 5 is moved according to Figure 1 to the left along the displacement axis B and thereby the piston 3 and thus the master cylinder 1, 2 depending on the active trajectory 6 (which are in operative connection with the piston 3) actuated. Depending on the slope of the trajectory 6 results in a lateral force that facilitates the movement of the piston 3 either or more difficult. So a variable Betätigungskraftverlauf can be achieved. Since this is a principle of redistribution of work, however, the total workload must remain the same.

To adjust the operating force curve, the hydraulic pressure in the pressure line D is removed and fed via a check valve 7 to a readjusting cylinder 8, which has an adjusting piston 9. Exceeds this pressure on the annular surface 9.1 of Nachstellkolbens 9 in Nachstellzylinder 8, the force of a return spring 10 which is coupled via a rope 1 1 or another traction means and a guide roller 12 to the adjusting piston 9, the cam element actuator 5 in its displacement axis B to rotated, so that the pistons 3 come into engagement with a new active trajectory 6. By the check valve 7 ensures that the adjustment is not turned back. The check valve opens only when pressure is exceeded and then allows the adjustment of the Nachstellkolbens and thus the rotation of the actuating element 5. This is shown in Figure 2 in the illustrations a and b. If at an excessive pressure in the pressure line D of the adjusting piston 9 is acted upon and moves down in accordance with left figure b in Figure 2, it is about the attached to the adjusting piston 9 Seit 1 1 and the guide roller 12 which is connected to the actuating element 5, against the spring force of the opposing spring 10 is transmitted a rotary motion to the actuator and this rotated in the direction of arrow, whereby the piston 3 of the master cylinder from the trajectories (view a) and according to representation b in other then active trajectories 6 of the actuating element 5 engage.

As an alternative to the adjustment / rotation of the actuating element described above, one or more sensors or the exceeding of a certain force, e.g. Bearing force in combination with a mechanical or electrical mechanism take over the task of readjusting.

The number of indirectly acting master cylinder can be chosen arbitrarily. Instead of the two master cylinder 1, 2 shown here, only one master cylinder can be used or it can be arranged over the circumference of the actuating element more than two master cylinder, wherein a maximum number is limited by the available space.

The actuator according to the invention can be realized even with large operating force deviations, which are caused for example by component tolerances, automatically compensate for the force differences and readjusting the pedal force / actuating force. The use of the invention as an additional option in all clutch pedals instead of a simple force compensation mechanism is possible.

LIST OF REFERENCES

1 first master cylinder

2 second master cylinder

3 pistons

4 spring

5 actuator

6 trajectory

6.1 Leadership

7 check valve

8 adjusting cylinders

9 adjusting piston

10 opposing spring

1 1 rope

12 pulley

A longitudinal axis

B Displacement axis

D pressure hose

Claims

claims

1 . Actuating device, for example, for a clutch, in particular for motor vehicles, with a clutch pedal, which with a along a first longitudinal axis (A) displaceable piston (3) having master cylinder (1, 2) is operatively connected, wherein the master cylinder (1, 2) upon actuation the piston (3) via a pressure line (D) provides an actuating pressure for the actuation of the clutch, characterized in that with the clutch pedal an actuating element (5) is actuated, which has at least one trajectory (6) and that the piston (3) of the master cylinder (1, 2) with the trajectory (6) of the actuating element (5) is operatively connected and by a change in the trajectory (6) can be actuated.

2. Actuating device according to claim 1, characterized in that the actuating element (5) along a displacement axis (B) relative to the master cylinder (1, 2) is displaceable, at an angle (a) to the longitudinal axis (A) of the master cylinder (1, 2) is arranged.

3. Actuating device according to claim 1 or 2, characterized in that on the circumference of the actuating element (5) a plurality of different cam tracks (6) are formed.

4. Actuating device according to one of claims 1 to 3, characterized in that the longitudinal axis / n (A) of the master cylinder (1, 2) is arranged substantially at right angles to the displacement axis (B) of the actuating element (5) / are.

5. Actuating device according to one of claims 1 to 4, characterized in that the distributed with the circumferentially trajectories (6) of the actuating element (5) are a plurality of pistons (3) of a plurality of donor cylinders in operative connection.

6. Actuating device according to one of claims 1 to 5, characterized in that the / the piston (3) in the trajectories (6) by lateral guides (6.1) on the actuating element (5) and / or on the master cylinder (1, 2) out are. Actuating device according to one of claims 1 to 6, characterized in that the piston (3) of the master cylinder (1, 2) by the spring force of a compression spring (4) is acted upon in the direction of the actuating element (5) and thereby at the trajectory (6) is applied.

Actuating device according to one of claims 1 to 7, characterized in that upon displacement of the actuating element (5) along the displacement axis (B) of the / the piston (1, 2) depending on the slope of the trajectory (6) in the direction of the longitudinal axis ( A) of the master cylinder (1, 2) against the spring force of the compression spring (4) acting actuator force is acted upon / are.

Actuating device according to one of claims 1 to 8, characterized in that a feedback of a necessary actuating force to an actuator takes place, such that when the actuating force increases above a certain threshold, the actuating element (5) by the actuator of an active cam track (6), with which the piston (3) is operatively connected to another active curved path (6) can be switched.

Actuating device according to one of claims 1 to 9, characterized in that between the pressure line (D) and the actuating element (5) in a readjusting cylinder (8) displaceable adjusting piston (9) is arranged, which when exceeding a predetermined pressure in the pressure line ( D) acts on the actuating element (5) such that the actuating element (5) performs a rotational movement, so that the piston (5) of a master cylinder (1, 2) with a new cam track (6) is engaged.