The invention relates to a motor vehicle latch, in particular to a motor vehicle door latch, having a locking mechanism essentially made of a catch and at least one pawl, furthermore having an operating lever mechanism for the locking mechanism with at least one coupling lever and one release lever, wherein the coupling lever in its “coupled position” mechanically connects the release lever to the locking mechanism and in its “uncoupled” position separates the release lever from the locking mechanism, and having an inertia element for guiding the coupling lever.

As a rule, the motor vehicle latches described in the introduction are motor vehicle door latches, that is, for example, motor vehicle side door latches, motor vehicle hatchback latches, or motor vehicle front hood latches. In principle, however, the term motor vehicle latch may also include seat latches or the like.

With motor vehicle latches, and in particular with motor vehicle door latches, in principle there is the danger that in a crash event, that is, during an accident, with associated increased deceleration forces acting on the motor vehicle latch, the operating lever mechanism will be deflected in an undesired manner and the associated locking mechanism and thus a motor vehicle door will be opened. As a consequence thereof, safety measures provided in or on the motor vehicle door, such as, for example, a side airbag or a side impact protection element, may have practically no effect for vehicle occupants. For this reason, the state of the art is currently working with so-called inertia elements, which, in a crash event, initially remain at rest or are deflected only slightly, and interrupt the operating lever mechanism. Because of this, for example an outer door handle deflected in a crash event can no longer unintentionally open the locking mechanism.

The state of the art according to WO 2015/090286 A1 describes a locking device for a motor vehicle, which locking device is equipped with a coupling member and a release actuating lever for the latch mechanism. If the release actuating lever is operated starting from a starting position, the coupling member couples the release actuating lever to the release lever to open the lock mechanism. However, if the release actuating lever is accelerated excessively, the coupling member does not ensure that the release actuating lever is coupled to the release lever to open the lock. That is, when the coupling member or coupling lever is in the “uncoupled” position, the operating lever mechanism is interrupted in a crash event.

A release lever that, using a coupling lever, may be coupled to an actuating lever, is realized in the generic state of the art according to DE 10 2016 112 182 A1. Moreover, the coupling lever is guided using a control lever. For its part, the control lever is moved using a control contour of an inertia lever.

The state of the art has in principle been proven and tested. However, in practice problems may occur in that the coupling lever, when its coupled position is changed to the “uncoupled” position, may at least slightly act upon the release lever. As a consequence thereof, some indifferent functional statuses are possible that may prevent or impede assured mechanical separation of the operating lever mechanism. This is the case, for example, on long time scales, that is, with motor vehicle latches that have or may have soiling, corrosion, etc. due to a long period of usage without a crash event. In fact, in some circumstances, such impairments may also have a negative impact on proper functioning. This is where the invention is intended to provide a remedy.

The underlying technical problem of the invention is to refine such a motor vehicle latch such that the change in the functional positions of the coupling lever proceeds with no problem, and specifically without neutral functional conditions being found. This is also and in particular to be provided for long time scales.

For solving this technical problem, in a generic motor vehicle latch, and in particular a motor vehicle door latch, the invention suggests that the inertia element has a guide contour for the coupling lever, which guide contour, in a crash event, separates the coupled coupling lever from the release lever and, without further mechanical contact, transfers the release lever to its “uncoupled” position.

Thus, in the context of the invention, in particular the inertia element with its guide contour ensures that, in a crash event, the coupling lever is transferred from its prior “coupled” position, assumed during normal operation, to the “uncoupled” position. As a rule, when the coupling lever is in the “coupled” position, an actuating pin of the coupling lever abuts a support surface on the release lever. As soon as the coupling lever is acted upon, for instance via an outer actuating lever or inner actuating lever, the actuating pin, by acting on the support surface of the release lever during normal operation, ensures that the release lever is normally pivoted and in this way the locking mechanism opens. This is because the pivot movement of the release lever corresponds to the pawl being removed from its engagement with the catch when the locking mechanism is locked.

Here the invention initially proceeds from the understanding that the inertia element, at least at the beginning of the crash event, retains its undeflected position, the resting position and the position used during normal operation. As a consequence thereof, the guide contour may interact with the coupling lever. In this context, according to the invention the guide contour ensures not only that the coupling lever is mechanically separated from the release lever, but according to the invention the guide contour on the inertia element moreover ensures that the coupling lever, after the mechanical separation from the release lever in a crash event, is transferred to its “uncoupled” position without further mechanical contact with the release lever.

In this manner any indifferent functional conditions are prevented in the first place. This even holds true for the situation in which the inertia element is increasingly deflected during the interaction of the guide contour with the coupling lever in a crash event. This is because the guide contour on the inertia element is advantageously equipped with a lifting flank for a contour pin of the coupling lever for this purpose. Due to the interaction between the guide contour on the inertia element or its lifting flank and the guide pin of the coupling lever, what is attained overall is that at the beginning of the crash event the coupling lever is mechanically separated from the release lever, and during its movement it passes the release lever collision-free without mechanical contact and then assumes its “uncoupled” position. The same is true for the instance in which the inertia element is increasingly deflected during the crash event.

In fact, the lifting flank, as a component of the guide contour on the inertia element, advantageously ensures that during the transition of the coupled coupling lever into the “uncoupled” position the actuating pin that is on the coupling lever and that interacts with the support surface on the release lever is guided along the affected support surface of the release lever, and specifically with clearance. The interaction between the guide contour or its lifting flank on the inertia element and the contour pin of the coupling lever ensures overall that the locking mechanism always assumes and retains its locked position, specifically even if, during a crash event, the operating lever mechanism experiences a deflection due to the deceleration forces acting on it and, as a consequence thereof, the coupling lever is deflected.

This is because the deflection of the coupling lever, using the guide contour on the inertia element, is intentionally converted to the transition of the coupled coupling lever to its “uncoupled” position, and specifically without this involving or being able to involve mechanical contact with the release lever. Because of this, the interplay between the contour pin of the coupling lever and the guide contour on the inertia element may also be adjusted and defined such that the ultimate effect is that the temporal transition of the coupling lever from the “coupled position” to the “uncoupled” position may be influenced. That is, depending on the design of the contour pin and the guide contour, different velocities of the coupling lever during a crash event may be realized during the transition from the “coupled” position to the “uncoupled” position. In the state of the art to date this has not been possible, especially according to the invention explicitly in this process a mechanical contact between the coupling lever and the release lever is prevented, so that the “transition velocity” is ultimately determined solely by the design of the contour pin and the guide contour or its lifting flank. This is where the essential advantages are found.

According to one advantageous embodiment, an actuating spring that pre-stresses the coupling lever towards the guide contour on the inertia element is associated with the coupling lever. The actuating spring is in general embodied as a leg spring. The leg spring has a wound section and two legs. The wound section may be arranged wound about a swivel pin as a component of an actuating lever.

The two legs are in general a fixing leg and a clamping leg. The fixing leg of the actuating spring associated with the coupling lever is in general fixed on the actuating lever. In contrast, the free clamping leg can act on the coupling lever. In this context, the clamping leg works on a spring journal that is on the coupling lever and that is described in greater detail in the following.

In addition to the actuating spring on the actuating lever, in general a restoring spring is also provided that acts on the inertia element in the direction of its undeflected position. That is, the restoring spring ensures that the inertia element is transferred back to its undeflected position in a crash event and when it assumes a deflected position after the deceleration forces associated with the crash event have ceased. To this end, the restoring spring is advantageously embodied as a leg spring.

The wound section of the leg spring or restoring spring may surround a bearing journal of the inertia element pivotable about the bearing journal. One leg of the restoring spring is anchored in a lock housing, for example, while the other, free leg of the restoring spring ensures that the inertia element is acted upon in the direction of its undeflected position.

The coupling lever is in general arranged rotatable on the actuating lever addressed in the foregoing. To this end, the coupling lever has a pivot pin that engages in a corresponding bearing opening that is in the actuating lever and that accommodates the pivot pin. Moreover, the coupling lever has at least one pin that engages in a guide contour of the actuating lever. In general, in addition to the pivot pin rotatably engaging in the bearing opening of the actuating lever, two additional pins are provided on the coupling lever that jointly engage in the guide contour of the actuating lever. The two pins of the coupling lever ensure that, in a crash event, the coupling lever executes a guided pivot movement with respect to the actuating lever during the transition from the “coupled” position to the “uncoupled” position. The two pins on the coupling lever that engage in the guide contour on the actuating lever are a spring journal and a contour pin.

The spring journal interacts in general with the actuating spring, addressed in the foregoing, which pre-stresses the coupling lever towards the guide contour on the inertia element. In contrast, the contour pin is embodied and set up to interact with the guide contour and in particular with the lifting flank as a component of the guide contour, which has already been described in the foregoing.

In normal operation, this design is such that the coupling lever assumes its “coupled” position. This corresponds to the actuating pin on the coupling lever abutting the support surface of the release lever. The actuating pin on the coupling lever is normally arranged on a side of the coupling lever opposing the two guide pins and the pivot pin. Because the actuating pin of the coupling lever abuts the support surface of the release lever, in normal operation the operating lever mechanism being acted upon leads to, for instance, the coupling lever being acted upon via an outer actuating lever and/or inner actuating lever and itself deflecting the release lever in order in this manner to open the locking mechanism disposed in the lock position. In fact, the release lever here ensures that in general the pawl is disengaged from its engagement with the catch. As a consequence thereof, the catch opens, spring-loaded, and releases a previously captured striker. This is the usual functionality in normal operation. Here, the inertia element assumes its rest position or its undeflected position.

If there is a crash event, however, deceleration forces act on the operating lever mechanism. These deceleration forces lead to the actuating lever and also the coupling lever being deflected. Since the coupling lever is borne on the actuating lever and, in addition, the contour pin of the coupling lever in this case interacts with the guide contour on the inertia element, the interaction between the contour pin of the coupling lever and the guide contour or its lifting flank on the inertia element overall ensures that the coupled coupling lever is transferred to the “uncoupled” position.

Since in this process there is no further mechanical contact between the coupling lever and the release lever, because the actuating pin originally abutting support surface of the release lever in normal operation is guided along the support surface, with a clearance, during the transition to the “uncoupled” position, it is only the interplay between the guide contour on the inertia element and the contour pin of the coupling lever that determines the movement of the coupling lever and also any velocity during the transition from its “coupled” position to the “uncoupled” position. This is where essential advantages of the invention are found.

