阅读说明：本技术 齿轮、尤其是驻车棘轮 (Gear, in particular parking ratchet ) 是由 U·迈尔 于 2020-04-17 设计创作，主要内容包括：本发明涉及齿轮(10)、尤其是驻车棘轮,其包括环形体(1)。环形体具有布置在环形体的外圆周上的用于嵌入棘爪(20)的第一啮合部(2)以及布置在环形体的内圆周上的用于与轴(30)形状锁合地连接的第二啮合部(3)。(The invention relates to a toothed wheel (10), in particular a parking ratchet, comprising a ring body (1). The annular body has a first engagement part (2) arranged on the outer circumference of the annular body for engaging in the pawl (20) and a second engagement part (3) arranged on the inner circumference of the annular body for form-locking connection to a shaft (30).)

1. Gear (10) comprising a ring body (1) having:

a first engagement section (2) arranged on the outer circumference of the annular body for engaging a pawl (20),

a second engagement section (3) arranged on the inner circumference of the annular body for a form-fitting connection to a shaft (30),

-wherein the second toothing (3) is designed such that the toothed wheel (10) is stretched in the radial direction relative to a positively connected shaft when the pawl (20) is engaged in the rotating toothed wheel (10).

2. A gear wheel according to claim 1, wherein the second meshing portion (3) has a plurality of teeth (5) with inclined tooth flanks (5a, 5 b).

3. A gear wheel according to claim 2, wherein the angle a of the opening of two mutually adjoining tooth flanks (5a, 5b) in the direction of the axis (98) is selected such that a self-locking of the shaft (30) is avoided and a return of the shaft (30) after the parking lock has been unloaded is ensured.

4. A gear according to claim 3, wherein the angle is 140 ° ≦ α ≦ 166 °.

5. A gear according to claim 3, wherein the angle is 150 ° ≦ α ≦ 156 °.

6. Gear according to claim 1, wherein the gear (10) is a parking ratchet for a parking lock.

7. A gear wheel according to any of claims 1-6, wherein the first and second meshing parts (2, 3) are radially acting meshing parts.

8. Parking lock comprising a gear wheel according to any of claims 1 to 6 and a shaft (30), on which the gear wheel (10) is arranged.

Technical Field

The invention relates to a gear wheel, in particular a parking ratchet for an automatic transmission, an automated transmission or an electric drive, and a parking lock.

Background

The park lock is a mechanical latch of the transmission output shaft to the transmission housing. For this purpose, pawls fastened to the housing are often engaged in the meshing wheels of the output shaft. For road vehicles with electric traction drives, mechanical parking locks are often required which brake the drive when the vehicle is stationary in order to avoid unintentional rolling of the vehicle.

This is usually achieved by an activatable pawl which engages in a groove of the gear wheel, in particular of the parking ratchet. When the parking lock is not engaged at rest, but rather at low vehicle speeds, a striking of the parking lock may occur when the pawl is engaged. This is the case, for example, when the vehicle is stopped in a gentle slope. This also occurs when there is a "tooth-to-tooth position" when the parking lock is engaged and the pawl can only be engaged when the vehicle rolls over. This situation also occurs when the parking lock is engaged by the vehicle driver before the vehicle is completely stationary. The parking lock, in particular the pawl and the parking ratchet, must be dimensioned such that it withstands this load.

In an electric traction drive, the rotor of the motor has a significant moment of inertia. When the parking lock is engaged at a low speed, not only the vehicle but also the rotor of the electric machine must be decelerated, which results in the parking lock being subjected to a great impact load. The crash energy is absorbed by the subsequent torsional vibration processes, which are additional loads on the system and which are not comfortable for the vehicle occupants.

Axially translating annular springs are known as structural elements which cushion and dampen impacts, for example as damping springs in railway vehicles.

Disclosure of Invention

The object of the invention is to provide an alternative gear, in particular a parking ratchet, and an alternative parking lock.

This object is achieved by a gear having the features of claim 1. The object is also achieved by a parking lock device having such a gear. Preferred embodiments result from the dependent claims.

The toothed wheel, which is in particular a parking ratchet for an automatic transmission, an automated transmission or an electric drive, comprises a ring body. A first engagement portion for engaging the pawl is disposed on an outer circumference of the ring body. A second engagement for a form-locking connection (formschlussig) to the shaft is arranged on the inner circumference of the annular body. Other terms for the parking ratchet are parking lock ring or parking gear.

The first engagement portion is configured to cooperate with the pawl in a known manner. The second engagement part is provided for form-locking mounting on a shaft of the transmission. The shaft has a third meshing portion corresponding to the second meshing portion of the gear.

An engagement is understood to mean a profile of a structural element, in particular of a ring or of a shaft, which has serrations, tines or wedges for establishing a connection and/or for increasing friction. The term toothing can be seen not only as a shape and arrangement of the teeth, but also as a manufacture of the teeth.

The parking lock device includes the previously described gear and a shaft to which the gear is mounted. In the installed state of the parking lock, the second and third engagement parts are preferably arranged radially opposite one another with positively interlocking, interlocking flanks. In other words, there is a shaft-hub connection, which is preferably realized by means of a meshing fit (also referred to as a spline). A mesh-type fit is a so-called multiple follower connection, in which torque is transmitted by the tooth flanks. The shafts are externally meshed, while the gears are internally meshed. The meshing engagement may be in the form of a spline shaft or a radially oriented face tooth engagement (Hirth-Verzahnung), for example. Thus, power, torque or rotational speed may be transferred from the shaft to the gear.

The second and third engagement portions do not have to be radially active, i.e. arranged radially opposite. The second and third engagement portions may also act axially, i.e. also extend in the axial direction. Face tooth engagements are examples of flat lateral engagements for axial action.

The gear wheels can be mounted on different shafts of the transmission, in particular on the transmission input shaft, on an intermediate shaft of the transmission, on a driven shaft or on a shaft connected to a corresponding shaft. Particularly preferably, the shaft is a rotor shaft of an electric machine, since the transmission can reduce the torque of the wheels via gear ratios accordingly. Therefore, the specification of the gear can be determined particularly small.

The second toothing is in particular designed such that, when the pawl is engaged in the rotating gearwheel, the gearwheel is stretched in the radial direction relative to the positively connected shaft.

Preferably, the second and third toothing systems have a plurality of teeth with inclined flanks.

The surfaces of the flanks of the teeth of the second and third toothing can be designed in a wide variety of ways. The inclined tooth flanks can be, for example, flat or convex in their surface, i.e. for example rounded. The convex flanks prevent what is known as edge loading (katentgen) when the second and third toothing are twisted. It is conceivable that only the second engagement section is embodied convexly and the third engagement section is embodied flatly, or that only the third engagement section is embodied convexly and the second engagement section is embodied flatly. It is also conceivable for both the second and the third engagement section to be embodied convexly. → Hertz stress.

If a pawl of the parking lock device snaps into the first engagement portion during rotation of the shaft to which the parking ratchet wheel is mounted, the gear wheel is twisted with respect to the shaft and stretched in the circumferential direction. In other words, the diameter of the gear becomes larger. Here, the gear absorbs the impact energy during the time the gear dampens the torque impact. Furthermore, the load acting on the pawl is thereby significantly reduced. Furthermore, the resulting torsional vibration is also damped by the friction of the second engagement part, as a result of which the parking lock device damps the subsequent torsional vibration of the torsional vibration system more quickly. During this process, the gears are substantially under tension load. In general, therefore, the invention makes it possible to achieve an optimum energy absorption, i.e. a uniform energy distribution on the annular body as a result of deformation of the annular body.

The angle of two adjacent tooth flanks is preferably selected such that a self-locking of the shaft is avoided and a return of the shaft after the parking lock has been unloaded is ensured. In a preferred embodiment of the invention, the angle α of the two tooth flanks adjoining one another which opens in the axial direction has an angle of between 140 ° and 166 °.

This angle range prevents, on the one hand, self-locking of the parking lock system which occurs at too small an angle. In other words, in this angular range, a self-locking is prevented when the second and third engagement parts are twisted relative to each other, wherein the parking lock system comprises at least a shaft and a gear. Self-locking should be avoided because after the pawl has been pulled out, a rest position can occur, wherein the rest position means that the second and third toothing do not twist relative to one another, i.e. the diameter of the gear wheel is minimal. On the other hand, this angular range enables a spring travel that is sufficiently large for absorbing impact energy. Too large an angle reduces the spring travel.

An angle between 150. ltoreq. alpha.ltoreq.156 has proven to be particularly preferred. This narrow angular range is optimal for preventing self-locking on the one hand and for a sufficiently large spring travel on the other hand.

According to another aspect of the present invention, a parking lock device is proposed, which comprises the previously described gear wheel and a shaft on which the gear wheel is arranged. In this sense, the advantages explained for the gear wheels also apply to the parking lock with such gear wheels.

The invention is not limited to the combinations of the features specified in the independent or dependent claims. Furthermore, the possibility arises of combining individual features with one another, which are derived from the claims, the subsequent description of preferred embodiments of the invention or directly from the drawings. The claims reference to the drawings by using reference signs is not intended to limit the scope of the claims.

Drawings

Advantageous subsequently elucidated embodiments of the invention are shown in the drawings. Wherein:

FIG. 1 shows a gear in a preferred embodiment in an axial cross-sectional view;

FIG. 2 illustrates the gear of FIG. 1 in perspective;

FIG. 3 shows the gear of FIG. 1 with a preferred angle of the second engagement;

fig. 4a, 4b show the properties of inclined tooth flanks, which can be used, for example, in the embodiments according to fig. 1 to 3.

Detailed Description

Fig. 1 shows a gear wheel 10 in the form of a parking ratchet of a parking lock device, not shown in detail, of a vehicle transmission, not shown, and a pawl 20, which engages in a first engagement portion 2 of the parking ratchet 10. The parking ratchet 10 is arranged coaxially with the axis 98. The pawl 20 is arranged coaxially with the axis 99. The two axes 98, 99 are arranged axially parallel to one another.

The parking ratchet 10 comprises a ring body 1. The ring body 1 includes a first engagement portion 2 for engaging the ratchet 20, which is disposed on an outer circumference of the ring body 1. The annular body 1 furthermore comprises a second engagement section 3 arranged on the inner circumference of the annular body 1 for form-locking connection with a shaft, not shown. The two engagement parts 2, 3 are radially acting engagement parts. The first toothing system 2 has teeth 4 with tooth flanks 4a, 4b with straight teeth in a known manner. Between adjacent teeth 4 there are corresponding recesses. The inner mesh part 3 has teeth 5 with lateral flanks 5a, 5 b. Unlike the tooth flanks 4a, 4b of the teeth 4 of the first tooth system 2, the tooth flanks 5a, 5b of the teeth 5 of the second tooth system 3 are inclined. An angle α exists between adjacent inclined tooth flanks 5a, 5 b. The angle alpha is in the range of 150 DEG alpha 156 DEG (see FIG. 3). In other words, the elevation angle of the tooth faces 5a, 5b is 12 DEG ≦ β ≦ 15 deg.

Fig. 2 shows the parking ratchet 10 of fig. 1 and a shaft 30 on which the parking ratchet 10 is arranged in a perspective view. The shaft 30 (which is a rotor shaft of the motor) has a third engagement portion 32 that corresponds to the second engagement portion 3 of the parking ratchet 10. The third toothing system 32 is thus a radially acting toothing system with teeth 34, i.e. extending in the radial direction. The teeth 34 have inclined tooth faces 34a, 34 b. The tooth flank 34a bears against the tooth flank 5a, while the tooth flank 34b bears against the tooth flank 5 b. The shaft 30 (which is currently the rotor shaft of an electric motor not shown in detail) is transferred by its contact surfaces 34a, 34b to the contact surfaces 5a, 5b and thus to the parking ratchet 10 in a form-locking manner.

If the pawl 20 is caught in the first engagement portion when the parking ratchet 10 rotates, the parking ratchet 10 is twisted with respect to the shaft 30 and is pulled in the circumferential direction 97, that is, in other words, the radius of the parking ratchet 10 becomes large. Here, the parking ratchet 10 also absorbs the impact energy when the parking ratchet buffers the torque impact. As a result, on the one hand, the load acting on the tooth flanks 20 can be significantly reduced and, on the other hand, the resulting torsional vibrations can be damped by the friction of the inner toothing.

Furthermore, the resulting torsional vibration is damped by the friction of the second engagement portion, thereby making the parking lock apparatus more quickly damp the subsequent torsional vibration of the torsional vibration system. During this process, the gears are substantially under tension load. In general, therefore, the invention makes it possible to achieve optimum energy absorption, i.e. a uniform energy distribution over the annular body by deformation of the annular body.

In the present example, the torsional vibration system can be described in a simplified manner as follows: the rotor of the motor performs torsional vibration. The torsion spring is formed by the elasticity of all components which are in force closure when the pawl is engaged. This is mainly the elasticity of the respective portions of the connecting shaft(s), the elasticity of the parking ratchet 10, the elasticity of the pawl 20, and the elasticity of the housing portion that absorbs the force from the pawl support portion. The degree of vibration is essentially constituted by the moment of inertia of the rotor of the electric machine.

Fig. 3 shows the parking ratchet of fig. 1, wherein additionally a preferred angle α is drawn, which is currently between 150 ° and 156 °.

Also shown is the elevation angle beta. The angle β is spanned by a tangent line extending through point P1 and a connecting line extending through points P1 and P2. The point P1 is a point where the adjacent tooth faces 5a, 5b intersect, and the intersection point has a minimum distance r1 with respect to the axis 98 of the parking ratchet 10. P2 is the point where the adjacent tooth faces 5a, 5b intersect and the intersection point P2 has the greatest distance r2 with respect to the center point of the parking ratchet 10. The angle beta is a so-called elevation angle and is 12 DEG-beta-15 deg.

The formulaic relationship between angles α and β is:

α＝180°-2β。

fig. 4a and 4b show the properties of inclined tooth flanks, which can be used, for example, in the embodiments according to fig. 1 to 3. In fig. 4a, the teeth 5 have inclined and flat flanks 5a, 5 b. The flanks 34a, 34b of the teeth 34, on the other hand, are embodied obliquely and convexly. In fig. 4b, the opposite is: the flanks 34a, 34b of the teeth 34 are embodied obliquely and flatly, while the flanks 5a, 5b of the teeth 5 are embodied obliquely and convexly. Fig. 4b shows the convexly rounded tooth flanks 5a, 5b of the parking ratchet 10 without an axle.

The invention is fully described and explained with the aid of the accompanying drawings and description. The description and illustrations are to be understood as examples and not restrictive. The invention is not limited to the disclosed embodiments. Other embodiments or variations will occur to those skilled in the art upon a reading of the specification and a study of the drawings, the disclosure and the appended claims.

In the claims, the words "comprising" and "having" do not exclude the presence of additional elements or steps. The indefinite article "a" does not exclude a plurality. A single element or a single unit may fulfil the functions of several of the units recited in the claims. A simple reference to some measures in various different dependent claims should not be construed as: combinations of these measures cannot be used with equal advantage.

List of reference numerals

1 annular body

2 first engaging part, outer engaging part

3 second engaging part and inner engaging part

4 teeth, teeth of the first engaging part

4a, 4b tooth surface

5 teeth, a plurality of teeth

5a, 5b tooth surface, abutment surface

6 recess (es) of the first engagement portion

7 recess (es) of the second engagement portion

10-gear parking ratchet wheel

20 ratchet pawl

30 shaft and rotor shaft

32 third engagement part

34 teeth, teeth of the third engaging part

34a, 34b tooth surface, abutting surface

97 shaft, direction of rotation of the gear; direction of stretching (circumferential direction)

Axis of 98 gears, shaft

99 axis of oscillation of pawl

Point of the inner mesh of P1 having the smallest distance from the center point

Point of the inner mesh part of P2 having the largest distance from the center point

t tangent line

d P1 and P2

r1 radius, distance between center point and P1

r2 radius, distance between center point and P2