DE102020127412A1 - Parking lock for a transmission and transmission with a parking lock and drive train - Google Patents

Abstract

The invention relates to a parking lock for a transmission and a transmission and a drive train. Known controls for parking locks of this type are often constructed in a complicated manner or are subject to a great deal of wear and tear. A parking lock for a transmission is therefore proposed with a parking lock wheel that is operatively connected to the output of the transmission and a locking element acting on the parking lock wheel, as well as a first actuator and a control element, the locking element for blocking the output by means of the first actuator using a worm drive element on the control element can be brought into engagement with the parking locking wheel in a locked position, the first actuator mechanically acting tangentially to a longitudinal axis on a control vane of the control element, the control vane having a curved active surface for absorbing a mechanical force of the first actuator and the curved active surface being shaped in this way is that a movement axis of the first actuator in different rotational positions of the control element is essentially perpendicular to a surface normal of the curved active surface at a respective contact point between the first act uator and the active surface is aligned so that lateral forces are reduced to the first actuator.

Description

The invention relates to a parking lock for a transmission according to the preamble of claim 1. The invention also relates to a transmission and a drive train.

Parking locks and transmissions or drive trains equipped with such a parking lock are used in particular in motor vehicles in connection with automatic transmissions or two-clutch transmissions or electric axle systems. The parking lock serves to lock an output of such a transmission in order to prevent the vehicle from rolling away by means of the chassis components connected to the output and the wheels of the motor vehicle. Such a parking lock can therefore be used in connection with a parking brake or as an alternative to it.

the DE 1 043 829 A discloses a parking lock in which a locking element is pivoted radially into a parking lock wheel. For this purpose, a claw in the locking element engages in the corresponding spaces between the claws on the parking lock wheel.

the DE 10 2005 015 161 A1 discloses a parking lock assembly for an automated transmission. A locking device is pushed axially into a parking ratchet wheel, the locking device and the parking ratchet wheel being designed as internally toothed and externally toothed gears, which then mesh. The teeth of the respective gears are each arranged radially.

the DE 10 2016 200 542 A1 describes a parking lock with an axial dog clutch. A locking element engages axially in a parking lock wheel. The parking lock is supported in its function by an axial spring.

the DE 10 2005 037 524 A1 describes a parking lock for a transmission, which is actuated with a lever mechanism. It is controlled via a ramp-like element, with the actual parking lock being implemented by means of locking elements that swing in radially.

Actuating mechanisms for known parking locks either have a complicated structure or are susceptible to wear.

The object of the invention is to improve the prior art.

The object is achieved by a parking lock according to claim 1. Advantageous refinements are described in the dependent claims 2 to 8. In further aspects, the object is achieved by a transmission according to independent claim 9 and a drive train according to independent claim 10.

Because the control vane has a curved effective surface for absorbing a mechanical force of the first actuator and the curved effective surface is shaped in such a way that a movement axis of the first actuator is essentially perpendicular to a surface normal of the curved effective surface at a respective contact point in different rotational positions of the control element is aligned between the first actuator and the active surface, transverse forces on the first actuator are effectively reduced.

As a result of the transverse forces that are absent or greatly reduced in the case of essentially vertical contact, there is significantly less wear on the first actuator.

• Ein „Abtrieb“ des Getriebes ist beispielsweise eine Abtriebswelle oder ein mit einer Abtriebswelle in Verbindung stehendes Element des Getriebes, wobei über den Abtrieb eine Verbindung zum Abtriebsstrang in Richtung beispielsweise der Räder oder einer Achse eines Kraftfahrzeuges hergestellt ist. Mittels eines solchen Abtriebs können sowohl von einem Motor eingeleitete Kräfte und Momente über das Getriebe sowie auch eine durch die Parksperre initiierte Sperrung des Abtriebs an übrige Teile des Abtriebsstrangs oder der Räder weitergeleitet werden.

The following terms are explained here:

• An “output” of the transmission is, for example, an output shaft or an element of the transmission connected to an output shaft, with a connection to the output train in the direction of, for example, the wheels or an axle of a motor vehicle being established via the output. By means of such an output, both forces and moments introduced by an engine via the transmission and also a blocking of the output initiated by the parking lock can be passed on to other parts of the output train or the wheels.

A “parking lock wheel” can be any element that is mechanically, for example non-rotatably, operatively connected to the output. Such a parking ratchet wheel is used to interact with other components in such a way that, for example, when the parking ratchet wheel is rotationally blocked, the output of the transmission can no longer be rotated and the output can therefore be blocked.

A "locking element" can be any component and any element that can act on the parking lock wheel, so that the parking lock wheel is inhibited or prevented from rotating, for example, so that the parking lock function is carried out correctly.

An "actuator" is, for example, a pneumatic or hydraulic cylinder, servomotor, lifting or actuating magnet, or any other device that performs a function in response to a control command, which then triggers a mechanical sequence.

A “control element” can be, for example, a lever transmission or another mechanical device which is suitable for transferring the movement originating from the actuator to the blocking element in such a way that it is put into operation. For example, such a control element is an intermediate component which is arranged between the blocking element and the actuator.

A "blocking" of the output describes a locking of the output in the sense of the complete restriction of, for example, free rotation of the parking lock wheel with the output.

A “worm gear element” can be any element that is suitable for converting a rotational movement into an axial movement with a mechanism that acts in the manner of a worm gear. Examples of this are an element designed in the manner of a thread or an element that acts on the principle of the wedge, in particular by means of rotation.

A "locked position" is such a position of the control element and/or the parking lock in which the parking lock performs its function, namely in which the mobility of the output of the transmission is restricted or blocked.

In the present case, "tangential to a longitudinal axis" means a direction which is tangential in the mathematical sense or in a range of, for example, -30° to 30° around such a tangential direction to the longitudinal axis and thus technically acts in a direction similar to a tangential direction , for example a force which acts tangentially to the longitudinal axis triggers a rotational movement of the control element. With a rotation of the control element, an exactly tangential direction is then only reached in a specific working point, which is no longer exactly tangential in the mathematical sense with a rotation away from this working point. It should be noted that the degrees of angle specified in the document relate to a full angle of 360°.

A “longitudinal axis” can be any axis that runs in a main direction along a transmission shaft, for example. For example, such a longitudinal axis is the axis around which the control element rotates.

A "control vane" can be, for example, a shoulder, a projection or any other device on the control that is suitable for absorbing forces, for example from the actuator, and passing them on to the control. In particular, the control vane absorbs forces in a direction tangential to the longitudinal axis or essentially tangential to the longitudinal axis.

A “curved active surface” can be any surface which is not straight or flat at least in partial areas of the surface and is suitable for being in an active connection with, for example, the actuator and absorbing forces.

A "contact point" is the point at which the actuator acts on the control vane with an active component, for example a piston. This contact point can move on the active surface during the movement, for example of the control element. The contact point can also be described as a contact area, in particular a minimal contact area.

In order to be able to actuate the parking lock particularly softly, smoothly and evenly, the active surface is designed to be continuously curved.

In one embodiment, the effective surface is concave and/or convex.

In particular, a concave or convex effective surface can be selected to match the exact position of the actuator in relation to the control element. For example, a concave effective surface can be formed if the control vane is arranged in a segment of a possible circular movement of the control element that faces away from the actuator. In contrast to this, a convex effective surface can be selected if the control vane is arranged in a segment of a possible rotational movement of the control element which faces the actuator. The arrangement is dependent on the respective zero position or rest position of the control.

In order to further minimize the wear of the parking lock, the first actuator has a convex end face, the convex end face being designed in particular in such a way that contact with the control vane occurs linearly or at points.

In a further embodiment, the first actuator has a mechanical energy storage device, it being possible for the blocking element to be brought into engagement with the support of the mechanical energy storage device when the actuator is in an activated state.

By means of such a mechanical energy store, the first actuator can be used as a trigger for the parking lock, the parking lock then being activated by energy stored in the mechanical energy store and then released.

A "mechanical energy store" can be any element that is suitable for storing energy by deforming a solid, compressing a gas or a combination of these properties with other active principles and releasing it again when required. For example, such a mechanical energy store is a spring, a helical spring, a gas pressure spring, a pressure store or another similar device.

In order to implement the mechanical energy store in a particularly simple manner, the mechanical energy store is a spring, in particular a helical spring or a gas pressure spring.

In one embodiment, the active surface has a sliding coating.

The friction between the actuator and the active surface can be significantly reduced by means of such a sliding coating, for example a friction-reducing sliding coating. This also significantly reduces the wear and tear on the parking lock.

In order to be able to activate and deactivate the parking lock alternately, a second actuator is assigned to the first actuator and the second actuator is particularly effective on a side of the control vane facing away from the first actuator.

A transmission with a parking lock according to one embodiment or more of the aforementioned embodiments realizes all the advantages resulting from such a parking lock.

A particularly compact parking lock that is realized as a result, for example, also allows the corresponding transmission to be made compact. Such a transmission is also very easy to maintain due to its structure.

A drive train with a transmission according to the embodiments mentioned has all the advantages mentioned of such a transmission. The drive train can thus be implemented very reliably and is also designed to be compact and maintenance-friendly.

• 1 eine schematische Darstellung einer Parksperre in deaktivierter Stellung in einer isometrischen Ansicht, sowie
• 2 eine Schnittdarstellung eines Betätigungsmechanismus der Parksperre in einer Seitenansicht.

The invention is explained in more detail below using exemplary embodiments. Show it

• 1 a schematic representation of a parking lock in the deactivated position in an isometric view, and
• 2 a sectional view of an actuating mechanism of the parking lock in a side view.

A parking lock 101 has a parking lock wheel 103 with an axle mount 102 . An output shaft (not shown) of a transmission is inserted in a rotationally fixed manner in the axle mount 102, so that the parking lock wheel 103 is connected to the output shaft in a positive or non-positive manner. The parking lock wheel 103 is freely rotatable with the output shaft in the transmission. The output axle directs the forces and torques of the transmission to an axle drive of a vehicle (not shown).

The parking lock wheel 103 has claws 104 on its end face, which are designed in the form of axial teeth. The parking lock wheel 103 and the output shaft can rotate about an axis 131 .

A claw wheel 105 with claws 106 arranged axially opposite the parking lock wheel 103 is arranged on the same axle 131 . The claws 104 of the parking lock wheel 103 and the claws 106 of the claw wheel 105 are mutually configured in such a way that the claw wheel 105 can mesh with one another when it is displaced along the axis 131 in the direction of the parking lock wheel 103 . The parking lock wheel 103 and the claw wheel 105 can then form a rotationally fixed connection.

The claw wheel 105 is in an exemption, so that the claws 106 and the claws 104 are disengaged ( 1 ).

Restoring springs 109 are arranged between the claw wheel 105 and the parking lock 103 and can push the claw wheel 105 away from the parking lock wheel 103 . In order to bring the claw wheel 105 into engagement with the parking lock wheel 103, these return springs 109 must be compressed in the opposite direction to their effective direction.

An activation wheel 107 is arranged on the same axle 131 . The activation wheel 107 is ring-shaped and has a flag 121 for its activation. The activation wheel 107 is axially fixed, but arranged in a non-rotating manner about the axis 131 .

Furthermore, the activation wheel 107 has end faces 123 which interact with projections 122 of the claw wheel 105 . The end faces 123 are designed in such a way that they run spirally in relation to the axis 131. The thickness of the activation wheel 107 thus varies around the circumference in the direction of the axis 131 in the region of each end face 123.

The claw wheel 105 has balls 108 on its outside, which form an axial bearing 110, so that the claw wheel 105 is accommodated in a housing 151 of the transmission so that it can move axially. Furthermore, the activation wheel 107 has grooves 112 arranged, which receive the claw wheel 105 rotationally fixed, but axially movable in the housing 151 of the transmission (not shown).

An actuator 111 is arranged acting on an end face 125 of the lug 121 of the activation wheel 107. The actuator 111 is a servo-motor linear drive which acts on the lug 121 in such a way that the activation wheel 107 performs a rotary movement as a result of the action of the actuator 111.

For this purpose, the actuator 111 has a piston 113 which is movable along a movement axis 130 and is in contact with the end face 125 of the vane 121 on one side. For this purpose, the end face of the piston 113 is spherical, that is to say spherical-convex, in order to enable contact which is as friction-free as possible.

The actuator 111 is constructed in its interior in such a way that the piston 113 is held in an extended position of the actuator 111 via a locking catch (internal structure not shown) in this extended position.

On an end face 124 of the lug 121, a ram 115 acts on the lug 121. The ram 115, like the actuator 111, is arranged tangentially to the activation wheel 107 and movable along the movement axis 130 in its direction of action. The plunger 115 is mounted in a bearing 119 which is accommodated in the housing 151 of the gear and is acted upon by a spring 117 .

The spring 117 is arranged in such a way that the direction of action of the relaxing spring 117 is in the direction of activation of the parking lock 101, i.e. counter to the direction of action of the actuator 111.

The front area of the plunger 115 is also shaped spherically. The contact of the piston 113 with the end face 125 and the contact of the plunger 115 with the end face 124 is therefore in each case point-like.

The flag 121 on the activation wheel 107 is curved. The curvature is arched along the axis 131 and selected so that when the activation wheel 107 rotates about the axis 131 by the angle of rotation α 200, there is contact both on the convex end face 124 to the plunger 115 and on the concave end face 125 to the piston 113 each is perpendicular or nearly perpendicular (see marked right angles in 2 ).

• In einer Freistellung (1) ist das Klauenrad 105 vom Parksperrrad 103 beabstandet, und wird durch die Federn 109 in dieser Position gehalten. Das Parksperrrad 103 mit der Antriebswelle kann damit frei im Getriebe drehen oder beispielsweise Antriebskräfte weiterleiten.

The function of the parking lock 101 is explained below:

• In an exemption ( 1 ) the dog wheel 105 is spaced from the parking lock wheel 103, and is held in this position by the springs 109. The parking lock wheel 103 with the drive shaft can thus rotate freely in the transmission or, for example, transmit drive forces.

The actuator 111 is not activated, the flag 121 of the activation wheel 107 is in an almost vertical position.

The activation wheel 107 is in such a position that it has a comparatively small thickness compared to the projections 122 of the claw wheel 105 and therefore no forces are transmitted to the claw wheel 105 either.

• Der Kolben 113 des Aktuators 111 wird eingefahren und die Rotation des Aktivierrads 107 dadurch freigegeben, der Stößel 115 wird durch die Relaxion der Feder 117 ausgefahren. Die Feder 117 drückt dabei auch den Kolben 113 in Richtung einer eingefahrenen Position.

If the activation wheel 107 and thus also the parking lock 101 are moved into a locked position, this is done by means of the actuator 111 as follows:

• The piston 113 of the actuator 111 is retracted and the rotation of the activation wheel 107 is thereby released, the plunger 115 is extended by the relaxation of the spring 117. The spring 117 also pushes the piston 113 in the direction of a retracted position.

The activation wheel 107 is thus rotated about the axis 131 . The spring 117 on the plunger 115 supports the process. Due to their spiral arrangement on the activation wheel 107, the end faces 123 now act on the projections 122 of the claw wheel 105.

The dog wheel 105 is moved axially toward the parking lock wheel 103 . In this case, the dog wheel 105 is guided by means of the axial bearing 110 in the housing 151 of the transmission. This is done in a non-rotatable manner in relation to the gear mechanism, which prevents the grooves 112 from rotating the claw wheel 105 . The return springs 109 are thereby compressed, the claws 104 and 106 engage in one another. This creates a positive connection between dog wheel 105 and parking lock wheel 103.

Due to the rotationally fixed mounting of the dog wheel 105 in the housing 151 of the transmission by means of the grooves 112, the parking lock wheel 103 is thus prevented from rotating. Forces are transmitted via the claws 104 and the claws 106 and the claw wheel 105 by means of the grooves 112 to the housing 151 of the transmission.

Because the rotation of the parking lock wheel 103 is blocked in this way, the output shaft and thus the entire output train of the vehicle can no longer be moved in rotation, so that the vehicle is prevented from rolling away.

Is the parking lock wheel 103 during the transfer of the parking lock 101 in a position so that teeth of the claws 104 and teeth of the Claws 106 are directly opposite and the claw wheel 105 cannot engage in the parking lock wheel 103, a rotational position is created at the latest when the vehicle rolls slightly, for example on a slope, in which the parking lock 101 securely engages.

During the transition between the release and the locked position, the plunger 115 slides over the end face 124 and the piston 113 over the end face 125, radially to the activation wheel 107. The curvature of the end face 124 and the end face 125 ensure that the contact between the piston 113 and the end face 125 and the plunger 115 and the end face 124 arises at points perpendicular to the respective surface normal of the end face 124 and the end face 125.

The deactivation of the parking lock 101 in the direction of an exemption ( 2 ) takes place in reverse order, namely by the actuator 111 being returned to its starting position, the activation wheel 107 being reset against the relaxation of the spring 117 and the claw wheel 105 being pressed back into the release position by the return springs 109.

The claws 104 and the claws 106 are then disengaged and the output shaft of the transmission can rotate freely.

Reference List

101

parking lock

102

axle mount

103

parking lock wheel

104

Nab

105

claw wheel

106

Nab

107

activation wheel

108

Bullet

109

return spring

110

thrust bearing

111

actuator

112

groove

113

Pistons

114

head face

115

pestle

116

head face

117

Feather

119

storage

121

banner

122

head Start

123

face

124

face

125

face

130

motion axis

131

axis

151

Housing

200

angle α

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was 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.

Patent Literature Cited

• DE 1043829 A [0003]
• DE 102005015161 A1 [0004]
• DE 102016200542 A1 [0005]
• DE 102005037524 A1 [0006]

Claims (10)

Parking lock (101) for a transmission with a parking ratchet wheel (103) in operative connection with the output (102) of the transmission and a locking element (105) acting on the parking ratchet wheel (103) as well as a first actuator (115) and a control element (107) , wherein the blocking element (105) for blocking the output (102) by means of the first actuator (115) using a worm gear element (107, 123) on the control element (107) can be brought into a blocking position with the parking ratchet wheel (103), wherein the first actuator (115) mechanically acts tangentially to a longitudinal axis (131) on a control vane (121) of the control element (107), characterized in that the control vane (121) has a curved effective surface (124) for absorbing a mechanical force of the first actuator (115) and the curved effective surface (124) is shaped such that an axis of movement (130) of the first actuator (115) in different rotational positions of the control element in Wes entlichen aligned perpendicular to a surface normal of the curved active surface at a respective contact point between the first actuator (115) and the active surface (125), so that transverse forces on the first actuator (115) are reduced. Parking lock according to claim 1 , characterized in that the active surface (124) is continuously curved. Parking lock according to claim 1 or 2 , characterized in that the active surface (124) is concave and / or convex. Parking lock according to one of the preceding claims, characterized in that the first actuator (115) has a convex end face, the convex end face being designed in particular in such a way that contact with the switching lug (121) occurs linearly or at points. Parking lock according to one of the preceding claims, characterized in that the first actuator (115) has a mechanical energy store (117), the blocking element (105) being supported by the mechanical energy store (117) when the actuator (115) is in an activated state is bringable. Parking lock according to claim 5 , characterized in that the mechanical energy store (117) is a spring, in particular a helical spring or a gas pressure spring. Parking lock according to one of the preceding claims, characterized in that the active surface (124) has a sliding coating. Parking lock according to one of the preceding claims, characterized in that the first actuator (115) is assigned a second actuator (111) and the second actuator (111) is particularly effective on a side of the control vane (121) facing away from the first actuator (115). is. Transmission with a parking lock according to one of Claims 1 until 8th . Drive train with a gearbox according to claim 9 .

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