CN107956869B

CN107956869B - Actuating system for parking lock

Info

Publication number: CN107956869B
Application number: CN201710968323.3A
Authority: CN
Inventors: 布平德尔·辛格·三久塔; Dr.沃尔弗拉姆·埃尔斯纳
Original assignee: Deere and Co
Current assignee: Deere and Co
Priority date: 2016-10-17
Filing date: 2017-10-17
Publication date: 2021-02-12
Anticipated expiration: 2037-10-17
Also published as: CN107956869A

Abstract

The invention discloses an actuating system for a parking lock. The actuation system includes an actuator (20), a spring-loaded locking device, and a park lock operating mechanism. An actuation system (10) according to the present disclosure enables selective disengagement of a cam lever (30) to achieve a park lock engaged configuration while an actuator (20) is displaced from an actuator disengaged configuration to an actuator engaged configuration. There is a time delay between reaching the park lock engaged configuration and reaching the actuator engaged position.

Description

Actuating system for parking lock

Technical Field

The present invention relates to the field of parking lock devices for vehicles. In particular, the present invention relates to the efficient operation of parking locks in dynamic vehicle situations.

Background

A parking lock is provided in a motor vehicle to prevent movement of the motor vehicle in a parked state of the motor vehicle. The parking lock maintains the vehicle in a parked state by preventing the wheels from rotating. To allow the vehicle to move, it is necessary to turn the parking lock into the disengaged state.

Typically, the park lock is actuated by an actuator to transition the park lock between the engaged and disengaged configurations. The parking lock includes a parking gear, a pawl, and a spring loaded cam. An actuator actuates the spring loaded cam to operatively engage and disengage the pawl from the park gear. When the pawl is engaged with the parking gear, the parking lock is in the engaged configuration. In the engaged configuration, the pawl prevents rotation of the gear by a positive connection between the gear and the surrounding housing. On the other hand, when the pawl is not engaged with the teeth on the parking gear, the parking lock is in the disengaged configuration. The spring force acting on the cam is configured to normally hold the park lock in the engaged configuration if no additional actuation force is acting on the system. Upon actuation by the actuator, the park lock is configured to move to the disengaged configuration against a spring force by means of an auxiliary power.

The actuator of the parking lock may be hydraulically actuated. In this case, the actuation of the park lock is delayed or limited due to the viscous action of the hydraulic fluid typically used in the vehicle hydraulic system. This results in a delay in the movement of the parking system from the engaged state to the disengaged state. This delay can lead to undesirable wear of the mechanical components and insignificant transition from the disengaged state to the engaged state.

Therefore, a mechanism for accelerating the transition of the parking lock system from the parking lock engaged state to the parking lock disengaged state is required.

Objects of the invention

The invention contemplates achieving at least one of the following objectives:

the object of the invention is to improve the parking lock engagement speed especially in cold conditions.

Another object of the present invention is to limit transmission of a rattle force (rate force) generated between a pawl and a parking lock gear to an actuator of a parking lock during operation of the parking lock; and is

It is a further object of the present invention to provide a distinct transition from the disengaged condition to the engaged condition.

Other objects of the invention will become apparent when the description of the invention is read in conjunction with the accompanying drawings. The drawings provided herein are for illustration purposes only and are not intended to limit the scope and ambit of the present disclosure.

Disclosure of Invention

According to the present invention, an actuation system for a parking lock is provided. The actuation system includes an actuator, a spring loaded locking device, a park lock operating mechanism.

The actuator is displaceable through a plurality of intermediate positions between an actuator engaged position and an actuator disengaged position. The spring loaded locking device is switchable between a park lock engaged configuration and a park lock disengaged configuration by the actuator. A park lock operating mechanism operatively connects the actuator and the locking device. The park lock operating mechanism includes a shaft, an actuator input member, and a cam lever.

The shaft defines an arcuate connecting channel. The shaft functionally cooperates in an axially rotatable configuration corresponding to displacement of the actuator between the actuator engaged position and the actuator disengaged position. An arcuate extension is configured on the shaft to define an arcuate connecting groove with a circumference of the shaft. The shaft is spring loaded by a shaft spring. The shaft spring exerts an opposing spring force proportional to the force exerted by the actuator between the park lock disengaged configuration and the park lock engaged configuration. At the end remote from the actuator input element, a shaft cooperates with a spring-loaded cam of the locking device via a first and a second link member. A first link cooperates with the shaft at one end and cooperates with the second link at the other end. The second link member cooperates with the spring-loaded cam at an end remote from the end cooperating with the first link member. The first link member and the second link member are relatively displaceable between a parking lock engagement configuration and a parking lock disengagement configuration corresponding to a rotational direction of the shaft. The first link member and the second link member are locked in the parking lock engagement configuration and the parking lock disengagement configuration by the shaft spring. The first link and the second link are displaced by the actuator between the park lock engaged configuration and the park lock disengaged configuration.

The actuator input element transmits displacement of the actuator to the shaft. The cam lever is pivotally mounted on the actuator input member. The actuator is at least one of a hydraulic actuator, an electronic actuator, and an electro-hydraulic actuator.

The cam rods are displaceable to selectively connect and disconnect the cam rods with respect to the arc-shaped connecting grooves. The cam lever is associated with a load corresponding to a frictional force between the cam lever and the arcuate extension.

A spring loaded follower is in constant contact with the cam lever. A spring loaded follower is configured to exert a force on the cam lever in a direction opposite the load.

Selective disengagement of the cam lever relative to the arcuate connecting channel enables the park lock engagement configuration to be at the at least one intermediate position. There is a time delay between reaching the park lock engaged configuration and reaching the actuator engaged position.

Drawings

The parking lock system of the present invention will now be described with respect to the accompanying drawings, in which:

FIG. 1 illustrates a perspective view of a park lock system having an actuator;

FIG. 2 illustrates a cross-sectional view of the park lock system shown in FIG. 1, particularly indicating the device, the park lock operating mechanism, and the actuator;

FIG. 3 illustrates a perspective view of the park lock system shown in FIG. 2 in an engaged configuration;

FIG. 4 illustrates a cross-sectional view of the park lock system as shown in FIG. 3 in an engaged configuration;

FIG. 5 illustrates a perspective view of the park lock system shown in FIG. 2 in a disengaged configuration;

FIG. 6 illustrates a cross-sectional view of the park lock system as shown in FIG. 5 in a disengaged configuration;

FIG. 7 illustrates a cross-sectional view of the park lock in an engaged configuration at a zero center position; and is

Fig. 8 to 10 illustrate the displacement of the parking lock operating mechanism between the disengaged configuration and the engaged configuration.

The embodiments herein and the various features and advantageous details thereof are described with reference to the non-limiting embodiments described below. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein.

Detailed Description

Currently available park lock assemblies with hydraulically operated actuators are directly engaged with the actuator through a solid link member. The time to displace the locking element from the disengaged to the engaged configuration with the parking lock gear depends on the operating speed of the actuator. In cold conditions, the viscosity of the hydraulic oil increases and thus the fluidity of the hydraulic oil is reduced. Thus, under cold conditions, the response time of a hydraulically actuated actuator increases. This increases the time for switching the park lock actuation system from the disengaged configuration to the engaged configuration. This leads to safety issues in cold conditions.

Fig. 1 illustrates a perspective view of a park lock actuation system, generally indicated by the numeral 10, for a vehicle park lock in accordance with the present invention. Fig. 2 illustrates a cross-sectional view of the park lock actuation system 10. The park lock actuation system 10 includes a locking device 12, an actuator 20, and a park lock operating mechanism 22. The actuator 20 is a hydraulic, electronic, or electro-hydraulic actuator. The locking device 12 is displaceable through a plurality of intermediate positions between a parking lock engaged configuration and a parking lock disengaged configuration. The locking device 12 includes a park lock gear 14, a locking member 16 and a spring loaded cam 18.

The locking element 16 is displaceable between an engaged configuration as shown in figures 3 and 4 and a disengaged configuration as shown in figures 5 and 6. The engaged configuration of the park lock actuation system 10 as shown in fig. 1 is achieved by displacement of the locking element 16 from engagement with a gear defined on the park lock gear 14. The disengaged configuration of the park lock actuation system 10 is achieved by displacement of the locking element 16 from a gear defined on the park lock gear 14. The spring loaded cam 18 is configured to keep the locking element 16 engaged between the teeth of the park lock gear 14. The disengaged configuration is achieved by using the force applied by the actuator 20 to displace the spring-loaded cam 18 against the spring force. Thus, upon release of the force of the actuator 20 causing the park lock actuation system 10 to be in the disengaged configuration, the spring loaded cam 18 tends to bring the locking element 16 into an engaged configuration with the teeth of the park lock gear 14.

A park lock operating mechanism 22 is operatively connected between the locking device 12 and the actuator 20, as will be described below with respect to fig. 4, 6 and 7 through 10, unless otherwise noted. The park lock operating mechanism 22 includes an actuator input member 24, a shaft 28, a cam lever 30 and a spring loaded follower 31. The parking lock operation mechanism 22 is mounted in the housing 23. The actuator input element 24 cooperates at a first end with the actuator 20 via an actuator rod 26. The actuator includes an actuator return spring 20b for providing a spring force in addition to the action of the hydraulic fluid to facilitate displacement of the actuator stem 26 during displacement from the actuator disengaged position to the actuator engaged position. The actuator input element 24 is connected at a second end to the shaft 28 at the center of the shaft 28. The shaft 28 is biased by a shaft spring (not shown) to configure the shaft 28 to return to the park lock engaged configuration. The actuator input element 24 is configured to convert linear motion of the actuator rod 26 into rotational motion of the shaft 28. The shaft 28 has a longitudinal axis X along a center that is generally orthogonal to the operating axis Y of the actuator stem 26. The second end defines a cam locking profile. The arc-shaped extension 28a extends tangentially to the circumference of the shaft 28. The arc-shaped connecting groove 28b is defined by the arc-shaped extension 28a and the circumference of the shaft 28. The arcuate connecting groove 28b extends along at least a portion of the length of the shaft 28. A cam lever 30 is pivotally mounted on the shaft 28. The pivot mounting point of the cam lever 30 serves as a fulcrum 32. The cam lever 30 is rotatable about a fulcrum 32 along a pivot axis Z. The pivot axis Z is parallel to the longitudinal axis X and offset by a predetermined distance.

In the engaged and disengaged configurations of the park lock actuation system 10, the cam rod 30 functionally cooperates with the arcuate extension 28a in the arcuate connecting groove 28 b. In the disengaged configuration of the park lock actuation system 10, as shown in fig. 6, the contact point between the arcuate extension 28a and the cam rod 30 is proximate the actuator 20. On the other hand, in the engaged configuration of the park lock actuation system 10, as shown in fig. 4, the contact point between the arcuate extension 28a and the cam rod 30 is remote from the actuator 20. The end of the cam lever 30 contacting the arc-shaped extension 28a is the load end of the cam lever 30. The load on the load end of the cam rod 30 is caused by the frictional force acting on the contact point between the arc-shaped extension 28a and the cam rod 30.

A spring loaded follower 31 biased by a spring 31a is mounted on the housing 23 such that the spring loaded follower 31 contacts the cam rod 30 between an engaged configuration and a disengaged configuration of the park lock actuation system 10. The spring loaded follower 31 exerts a force on the cam rod 30. The force is a force exerted on the cam lever 30 to overcome the load acting on the load end of the cam lever 30.

Further, a pair of

link members

34 and 36 are disposed between the spring-loaded cam 18 and the shaft 28 of the locking device 12. The pair of

link members

34 and 36 cooperate with each other at a pivot point at one end portion to be relatively displaceable with respect to each other.

Link members

34 and 36 cooperate with the shaft 28 and spring-loaded cam 18, respectively, at ends remote from the pivot point 33.

During travel of the actuator 20 from the engaged position shown in fig. 4 to the disengaged position shown in fig. 6, the actuator 20 rotates the actuator input member 24 and thus the shaft 28 about the longitudinal axis X as well. Because the cam lever 30 is also mounted on the actuator input member 24, movement of the actuator 20 causes the cam lever 30 to be displaced by the same degree/degree as the degree/degree (degree) of the shaft 28. In the case where the cam lever 30 moves, the spring-loaded follower 31 continues to contact the cam lever 30 and exerts a force equal to the spring force of the spring 31a of the spring-loaded follower 31.

In the disengaged configuration of the park lock actuation system 10, as shown in fig. 6, the fulcrum 32 is located between the force exerted by the spring loaded follower 31 on the cam rod 30 and the load on the cam rod 30 due to the frictional force between the arcuate extension 28a and the cam rod 30. Thus, the cam rod 30 serves as a 1-step operating lever in the disengaged configuration of the parking lock. The force exerted on the cam lever 30 is in a direction opposite to the load acting on the cam lever 30. When the actuator 20 reaches the disengaged position, contact between the arcuate extension 28a and the cam rod 30 achieves a minimum threshold load. Simultaneously, as shown in fig. 7, the

link members

34 and 36 move into a straight configuration and the pivot point 33 and the center of the shaft 28 are in line. This is a zero-center position or offset configuration of the park lock actuation system 10. In this position, the locking element 16 is disengaged from the park lock gear 14 of the locking device 12. The park lock actuation system 10 will remain in the zero center position until a park lock lever (not shown) is moved by an operator from the disengaged position to the engaged position, causing the actuator 20 to travel toward the engaged position.

When a parking lock lever (not shown in the drawings) is moved from the disengaged position to the engaged position by an operator, actuator 20 is caused to move toward the engaged position. The engaged position of the actuator 20 is in a direction opposite to that reached in the disengaged configuration of the park lock actuation system 10. At the beginning of the engaged configuration of the park lock actuation system 10, the arcuate extension 28a and the cam rod 30 are respectively caused to move away from each other in opposite directions as the actuator 20 travels toward its engaged position due to the displacement of the actuator input member 24 and the rotation of the shaft 28 caused by the actuator input member 24. Thus, a point is reached at which contact between the arc-shaped extension 28a and the cam rod 30 is lost, as shown in fig. 8. Although fig. 8 illustrates the cam lever 30 being released from the arc-shaped connecting groove 28b, those skilled in the art will appreciate that the contact between the arc-shaped extension 28a and the cam lever 30 may be lost even when the cam lever 30 is located in the arc-shaped connecting groove 28 b. This occurs when the spring force of the spring loaded follower 31 overcomes the frictional force between the arcuate extension 28a and the cam rod 30. Therefore, the load acting on the cam lever 30 is zero. Simultaneously, the spring loaded follower 31 moves laterally along the profile of the cam rod 30 such that the point at which the force is applied by the spring loaded follower 31 moves towards the loaded end of the cam rod 30. Because the load at the load end of the cam rod 30 is zero, the force provided by the spring loaded follower 31 and the movement of the actuator rod 26 transmitted to the shaft 28 and cam rod 30 causes the cam rod 30 to move out of the arcuate connecting groove 28 b. Since the contact between the arc-shaped extension 28a and the cam rod 30 is reduced (loss), the shaft 28 is rotated toward the engagement position by the movement of the actuator 20. This causes the park lock actuation system 10 to overcome the zero center position, as shown in fig. 7, resulting in relative movement between the

link members

34 and 36 about the pivot point 33. Fig. 9 illustrates an intermediate position of the arcuate extension 28a and cam rod 30 prior to being displaced by movement of the actuator 20 to travel toward the actuator engagement position shown in fig. 10. At this point, while the actuator 20 continues to move laterally toward the engaged position, the locking member 16 engages the park lock gear 14 of the locking device 12 due to the tendency of the spring loaded cam 18 to retain the locking member 16 in an engaged configuration with the park lock gear 14 of the locking device 12, as shown in fig. 3. Thus, although the lock device 12 has been moved to the engaged configuration and movement of the vehicle is inhibited, the actuator 20 continues to move laterally toward the engaged position. There is therefore a delay between the engaged configuration of the lock 12 and the movement of the actuator 20 to its engaged position. When the actuator 20 is moved to the engaged position, the cam rod 30 moves in the arc-shaped connecting groove 28b and engages with the arc-shaped extension 28 a. Thus, a load due to a frictional force between the cam rod 30 and the arc-shaped extension portion 28a is applied at the load end portion of the cam rod 30. In this position, the spring loaded follower 31 exerts a force on the cam rod 30 such that the force and load are on the same side of the cam rod 30. Thus, the cam rod 30 functions as a 2-step lever.

Thus, the parking lock operation mechanism 22 disengages the lock device 12 from the actuator 20. Thus, during engagement, the spring loaded cam 18 is disengaged from the actuator 20, thus causing the spring loaded cam 18 to bring the locking element 16 into engagement with the park lock gear 14. Simultaneously, the actuator 20 moves to the engaged configuration. Upon reaching the engaged configuration, the actuator 20 locks the locking member 16 in the engaged configuration with the park lock gear 14 until the park lock is actuated by the park lock lever to shift into the disengaged configuration.

Technical progress

The present invention has several technical advances, including but not limited to the implementation of a parking lock mechanism:

the parking lock performance under cold conditions is improved;

limiting transmission of a rattle force generated between the pawl and the parking lock gear to an actuator of the parking lock during operation of the parking lock; and is

The engagement efficiency of the parking lock is improved.

While the foregoing description has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains.

Claims

1. An actuation system (10) for a parking lock, the actuation system (10) comprising:

an actuator (20) displaceable through a plurality of intermediate positions between an actuator engaged position and an actuator disengaged position;

a spring-loaded locking device (12) switchable between a park-lock engaged configuration and a park-lock disengaged configuration by the actuator (20); and

a park lock operating mechanism (22) operatively connecting the actuator (20) and the spring-loaded locking device (12), characterized by: the parking lock operation mechanism includes:

a shaft (28) defining an arcuate connecting groove (28 b);

an actuator input element (24) that transmits displacement of the actuator (20) to the shaft (28); and

a cam lever (30) pivotally mounted on the actuator input element (24), the cam lever (30) being displaceable to selectively connect and disconnect the cam lever (30) with respect to the arcuate connecting groove (28 b);

wherein said selective disengagement of said cam lever (30) relative to said arcuate connecting groove (28b) effects said park lock engaged configuration at least one of said intermediate positions with a time delay between reaching said park lock engaged configuration and reaching said actuator engaged position.

2. The actuation system (10) of claim 1, wherein:

the shaft (28) functionally cooperates in an axially rotatable configuration corresponding to displacement of the actuator (20) between the actuator engaged position and the actuator disengaged position.

3. The actuation system (10) of claim 1, wherein:

an arcuate extension (28a) is configured on the shaft (28) to define the arcuate connecting groove (28b) with a circumference of the shaft (28).

4. The actuation system (10) of claim 1, wherein:

the cam lever (30) is associated with a load corresponding to a frictional force between the cam lever (30) and the arc-shaped extension (28 a).

5. The actuation system (10) of claim 1, wherein:

a spring loaded follower (31) is in constant contact with the cam lever (30), the spring loaded follower (31) being configured to exert a force on the cam lever (30) in a direction opposite to a load.

6. The actuation system (10) of claim 1, wherein:

the shaft (28) is spring loaded by a shaft spring that exerts an opposing spring force proportional to the force exerted by the actuator (20) between the park lock disengaged and park lock engaged configurations.

7. The actuation system (10) of claim 1, wherein:

the shaft (28) cooperates with a spring-loaded cam (18) of the spring-loaded locking device (12) at an end remote from the actuator input element (24) by means of a first link member (34) and a second link member (36), the first link member (34) cooperating with the shaft (28) at one end and with the second link member (36) at the other end, the second link member (36) cooperating with the spring-loaded cam (18) at an end remote from the end cooperating with the first link member (34).

8. The actuation system (10) of claim 7, wherein:

the first link member (34) and the second link member (36) are relatively displaceable between a parking lock engagement configuration and a parking lock disengagement configuration corresponding to a rotational direction of the shaft (28), the first link member (34) and the second link member (36) being locked in the parking lock engagement configuration and the parking lock disengagement configuration by a shaft spring.

9. The actuation system (10) of claim 7, wherein:

the first link (34) and the second link (36) are displaced by the actuator (20) between the park lock engaged configuration and the park lock disengaged configuration.

10. The actuation system (10) of claim 1, wherein:

the actuator (20) is at least one of a hydraulic actuator, an electronic actuator, and an electro-hydraulic actuator.