Gear transmission assembly for brake actuator and brake actuator

Abstract

The invention relates to a gearing arrangement (12) for a brake actuator (10), comprising the following features: a drive element (33), a first driven element (36), a second driven element (38), and a gearing output element (40), where the first driven element (36) and the second driven element (38) differ in transmission ratio with respect to the drive element (33), where the first driven element (36) and the second driven element (38) differ in transmission ratio with respect to the drive element (33). The first driven element (36) may be coupled to the geared output element (40) by a first clutch (42), the first clutch comprising a first drive body (50) and a first driven body (52), and wherein the second driven element (38) may be coupled to the geared output element (40) by a second clutch (46), the second clutch (46) comprising a second drive body (62) and a second driven body (64), the invention further relates to a brake actuator (10) having a gearing arrangement (12).

Description

Technical Field

[0001] The invention relates to a gear transmission assembly for a brake actuator and a brake actuator. Background Art

[0002] The dynamic requirements of brake actuators are very high, especially in the automotive sector. To meet these dynamic requirements, electromechanical brake actuators have so far been equipped with low-reduction gearing and brushless DC motors (known as brushless DC motors or BLDC motors) as drive motors. However, the cost of these motors is very high, which is why alternatives are sought.

[0003] Using conventional, i.e. brushed direct current motors (known as DC motors) as drive motors can reduce costs. Since such drive motors offer a relatively low motor output torque, the downstream gear transmission must provide a correspondingly high reduction ratio in order to achieve the required actuating force. However, the high reduction ratio comes at the expense of the adjustment time. In particular, the time required to lock the brake actuator (known as the "locking time": TTL) is critical for highly dynamic brake systems. Summary of the invention

[0004] The object of the present invention is therefore to provide a gear transmission assembly which can achieve the required adjustment force on the one hand and a short locking time on the other hand and which is easy and inexpensive to produce. In particular, the production costs of the gear transmission should be so low that the cost advantage of using a DC motor can compensate for the higher production costs of the gear transmission assembly.

[0005] Another object of the present invention is to provide a brake actuator which is inexpensive to produce and which provides the required regulating force with a short locking time.

[0006] The above-mentioned object is achieved according to the invention by a gear transmission assembly having the features of claim 1 and a brake actuator having the features of claim 16 .

[0007] Advantageous embodiments and further developments of the invention are defined in the dependent claims.

[0008] According to the present invention, a gear transmission assembly for a brake actuator comprises a driving element, a first driven element, a second driven element and a gear transmission output element, wherein the first driven element and the second driven element have different transmission ratios relative to the driving element. Therefore, when the gear transmission assembly is in operation, the rotation speed and torque obtainable from the first driven element are different from the rotation speed and torque obtainable from the second driven element, respectively.

[0009] In the gear transmission assembly according to the present invention, the first driven element can be further coupled to the gear transmission output element via a first clutch, the first clutch comprising a first driving body and a first driven body. The second driven element can be coupled to the gear transmission output element via a second clutch, the second clutch comprising a second driving body and a second driven body, and designed as an overrunning clutch. For example, the gear transmission output element can be operably connected to a brake pad, for example. To this end, the gear transmission output element can have spline teeth.

[0010] In a first embodiment of the present invention, the first clutch is designed as a torque limit clutch. The torque limit clutch is understood here and in the full text to preferably mean such a clutch, which can couple or separate two bodies to each other depending on the torque to be transmitted. The first clutch of the gear transmission assembly described herein is preferably configured to transmit a small torque within a specific torque threshold through the clutch. Overrunning clutch is understood here and in the full text to preferably mean a clutch, which couples or separates two bodies to each other according to the principle of a one-way clutch (Freilauf) depending on the direction of rotation to be transmitted. In particular, this second clutch can separate two bodies rotating at different speeds in the same direction from each other.

[0011] The second clutch is preferably designed as a one-way clutch, in particular a roller one-way clutch or a sprag one-way clutch. The rolling elements of the roller one-way clutch roll in the non-coupled state and are separated by the clamping spring in the coupled state. This enables a delay-free switching process from the coupling of the first driven element to the gear transmission output element to the coupling of the second driven element to the gear transmission output element.

[0012] Depending on the load applied to the gear transmission output element and the rotational directions of the first driven element and the second driven element, either the rotational speed and torque of the first driven element or the rotational speed and torque of the second driven element can be transmitted to the gear transmission output element. Thus, the transmission ratio of the gear transmission output element to the drive element can be changed according to the load applied to the gear transmission output element.

[0013] The first driven element and the second driven element represent two preferably different force flows and paths through the gear transmission assembly, which may include a gear transmission output element depending on the operating state. The first clutch and the second clutch can prevent the gear transmission assembly from being misaligned, i.e. stuck. The gear transmission assembly is preferably configured so that the first driven element has a higher speed and a lower torque than the second driven element during operation. The first driven element and the second driven element are preferably coupled to the drive element so that the first driven element and the second driven element have the same direction of rotation.

[0014] Therefore, the gear transmission assembly in the first embodiment can have the following operating states:

[0015] In a first possible operating state, the first driven element and the second driven element rotate in a first rotational direction. No load is applied to the gear transmission output element or a load that does not exceed the torque limit of the first clutch is applied. The first clutch connects the gear transmission output element to the first driven element. The second clutch decouples the gear transmission output element from the second driven element, so that the slower rotating second driven element is "overtaken" by the faster rotating gear transmission output element. The gear transmission output element has the speed and torque of the first driven element. For example, this operating state can occur if a brake pad operably connected to the gear transmission output element passes through the operating clearance of the brake (i.e., the distance of contact with the brake disc).

[0016] In a second possible operating state, the first driven element and the second driven element also rotate in the first rotational direction. A load exceeding the torque limit of the first clutch is applied to the gear transmission output element. The first clutch decouples the gear transmission output element from the first driven element. Once the rotational speed of the gear transmission output element drops at least to the rotational speed of the second driven element, the second clutch couples the gear transmission output element to the second driven element. Thus, the gear transmission output element has the rotational speed and torque of the second driven element. This operating state may occur, for example, if a brake pad operably connected to the gear transmission output element contacts and is pressed against a brake disc.

[0017] In a third possible operating state, the first driven element and the second driven element rotate in a second rotational direction opposite to the first rotational direction. No load is applied to the gear transmission output element or a load that does not exceed the torque limit of the first clutch is applied. Therefore, the first clutch can connect the gear transmission output element to the first driven element. Due to the principle of the second overrunning clutch, the speed of the first driven element in the second rotational direction is higher than the speed of the second driven element, which will cause the gear transmission output element to be connected to the second driven element. Therefore, the first clutch of the torque limit can separate the gear transmission output element from the first driven element. The gear transmission output element has the speed and torque of the second driven element. For example, this operating state can occur if the brake pad operably connected to the gear transmission output element is away from the brake disc.

[0018] The first drive body of the first clutch is preferably connected to the first driven element in a rotationally fixed manner. The first drive body can be connected to the first driven element in a form-fitting manner and / or in a material-bonded manner, in particular in the circumferential direction. In a first embodiment of the invention, the first drive body can be preloaded on the first driven body by a spring element. Thus, the first clutch can be connected by force fit.

[0019] The gear transmission output element is connected to the first driven element by a positive and / or form-fit connection. The torque limit of the first clutch can be adjusted by preloading. The spring element is preferably designed as a spring washer.

[0020] In particular, in the first embodiment of the present invention, the first driven body of the first clutch can be formed by a gear transmission output element, which can achieve a compact design and reduce the number of components in the gear transmission assembly.

[0021] In particular, in a first embodiment of the invention, the first drive body can be designed as a toothed disc, and the gear transmission output element can have a profile, which can engage with the toothed disc on the end face facing the toothed disc. The toothed disc is preferably and is understood to be a disc-shaped element having a toothed profile in the axial direction. Such an arrangement can reduce the spring force required for the drive component to be coupled to the gear transmission output element while maintaining the torque limit of the first clutch.

[0022] In a second embodiment of the present invention, the first clutch is designed as an angle-driven clutch. Here and throughout the text, the angle-driven clutch is preferably understood to mean a clutch that couples or decouples two bodies to each other depending on the rotation angle of at least one of the two bodies. In a second embodiment of the present invention, the coupling or decoupling preferably depends on the rotation angle of the first driven body. Depending on the rotation angle of the first driven body, either the rotational speed and torque of the first driven element or the rotational speed and torque of the second driven element can be transmitted to the gear transmission output element. In this way, the transmission ratio of the gear transmission output element to the drive element can be changed according to the rotation angle of the first driven body. Therefore, the rotational speed and corresponding torque applied to the gear transmission output element can be controlled according to the rotation angle and the stroke thereby.

[0023] The second embodiment of the gear transmission assembly is preferably designed so that the first driven body has a tooth segment that is connected to the gear transmission output element in a torsionally fixed manner, and the first driving body has a driving tooth that can engage with the tooth segment. The torsionally fixed connection of the tooth segment to the gear transmission output element is preferably understood to mean that the relative movement of the tooth segment causes the relative movement of the gear transmission output element, and vice versa. Here and throughout the text, the tooth segment is preferably understood to mean a non-infinitely arranged tooth geometry. Thus, for example, the tooth segment can be arranged on the circumference of a tooth segment gear with a tooth segment angle of less than 360°. This means that the tooth segment can only engage with the driving tooth within the tooth segment angle. Within the tooth segment, the first driving body and the first driven body can be connected to each other. In addition, there is preferably no longer any force transmission between the driving tooth and the tooth segment. Therefore, the first driving body and the first driven body can be separated from each other. The first driving body can be composed of the first driven element.

[0024] In a second embodiment of the gear transmission assembly, the first driven element is preferably coupled to the drive element via a third clutch. Thus, on the drive element side, the force path comprising the first driven element and the force path comprising the second driven element can be separated from each other. In the case of rotation in a first direction of rotation, the separation function is preferably performed by the second clutch. In the case of rotation in a second direction of rotation, which is preferably driven by the gear output element in the second embodiment of the gear transmission assembly, the second clutch is closed due to the principle of an overrunning clutch. The first clutch, which is designed as an angle-driven clutch, cannot usually be opened in the case of an increase in torque due to a misalignment of the gear transmission assembly, which may occur in the first embodiment. Therefore, misalignment of the gear transmission can be avoided by providing a third clutch.

[0025] Particularly preferably, the third clutch is designed as an overrunning clutch. As a result, in the first rotational direction, the first driven element can be driven by the driving element, while in the second rotational direction, misalignment of the gear transmission assembly can be avoided. The overrunning clutch is simple and space-saving, while also having a high efficiency. The third clutch is preferably designed as a one-way clutch, in particular a braced one-way clutch.

[0026] According to the first embodiment, possible operating states of the second embodiment of the gear transmission assembly will be explained as follows:

[0027] In a first possible operating state, the drive element rotates in a first rotational direction, so that the second driven element, which is preferably coupled to the drive element in a torsionally rigid manner, also rotates in the first rotational direction. The third clutch is preferably configured to transfer torque from the drive element to the first driven element along the first rotational direction. The drive teeth of the first drive body engage with the tooth segment so that the first clutch couples the gear transmission output element to the first driven element. The second clutch decouples the gear transmission output element from the second driven element, so that the slower rotating second driven element is "overtaken" by the faster rotating gear transmission output element. The rotational speed and torque are transmitted from the first driven element to the gear transmission output element, which also rotates in the first rotational direction. This operating state can occur, for example, if a brake pad operably connected to the gear transmission output element passes through the operating clearance of the brake (i.e., the distance of contact with the brake disc).

[0028] In a second possible operating state, the drive element also rotates in the first rotational direction. The tooth segments have moved to such an extent that there is no longer any force transmission between the drive teeth and the tooth segments. Therefore, the first clutch separates the gear transmission output element from the first driven element. As soon as the speed of the gear transmission output element drops to at least the speed of the second driven element, the second clutch connects the gear transmission output element to the second driven element. The speed and torque are transmitted from the second driven element to the gear transmission output element. The gear transmission output element rotates in the first rotational direction. If the tooth segments are connected to the gear transmission output element in a rotationally fixed manner, the tooth segments continue to rotate at the corresponding speed in this operating state. This can especially prevent the tooth segments from rubbing against the drive teeth. This operating state can occur, for example, if a brake pad operatively connected to the gear transmission output element contacts and presses against a brake disc. By means of the gear transmission assembly in the second embodiment, the operating clearance of the brake can be quickly passed through in a rotationally controllable manner, so that the brake pad is pressed against the brake disc with a high torque and a short path.

[0029] In the third possible operating state, the gear transmission output element rotates in a second rotational direction opposite to the first rotational direction. For example, this operating state can occur if the brake block operably connected to the gear transmission output element is away from the brake disc. The gear transmission assembly is preferably driven by the gear transmission output element. This can be achieved, for example, by designing a brake using the gear transmission assembly so that when the brake is locked, the removal of the brake block from the brake disc is driven by the release of the preload introduced into the brake. Due to the principle of the second overrunning clutch, the second clutch connects the gear transmission output element to the second driven element in the second rotational direction. The corresponding rotation can be transmitted to the drive element. In addition, the tooth segment connected to the gear transmission output element in a torsionally fixed manner is also correspondingly moved back so that it is engaged with the driving teeth of the first drive body again. Therefore, the second driven element is driven at a speed different from that of the drive element. The third clutch separates the first driven element from the drive element, thereby avoiding the misalignment of the gear transmission assembly.

[0030] In a further embodiment of the present invention, the gear transmission assembly comprises a planetary gear set, the planetary gear set comprises a planetary gear carrier, at least one planetary gear and a sun pinion, the planetary gear carrier is arranged on the planetary gear carrier, the sun pinion is connected to the sun shaft in a rotationally fixed manner, and the sun pinion meshes with the at least one planetary gear. As a result, a larger transmission ratio can be achieved in a relatively small installation space. In order to realize the function of the ring gear, the housing of the gear transmission assembly can have internal teeth, and the at least one planetary gear meshes with the internal teeth.

[0031] The second driven element can be formed by a planetary carrier. As a result, the second driven element can be decelerated relative to the drive element.

[0032] The second drive body can be formed by a planetary gear carrier and / or the second driven body can be formed by a gear output element. This allows a compact design and reduces the number of components in the gear assembly. If the first driven body of the first clutch is simultaneously formed by a gear output element, the first driven body and the second driven body are identical.

[0033] The gear output element can be arranged in a cylindrical recess of the planetary gear carrier. The rotation axis of the gear output element is therefore preferably located on the rotation axis of the sun shaft. The cylindrical recess can have a side surface which can be designed as a drive-side working surface of the second clutch. In this case, the rolling elements or clamping elements of the one-way clutch can interact directly with the side surface. This helps to reduce the number of components in the gear assembly.

[0034] The drive element can be formed by a drive gear which meshes with a sun wheel arranged on the sun shaft. The term "drive gear" preferably also includes a drive gear shaft on which the gear can be arranged. The sun wheel is preferably arranged on the sun shaft in a rotationally fixed manner. Particularly preferably, the drive gear has a smaller diameter than the sun wheel. This allows a further reduction in speed to be achieved.

[0035] The drive gear can be designed as a double gear, which has a first ring gear and a second ring gear connected to the first ring gear in a rotationally fixed manner, the second ring gear meshing with the sun gear. The diameter of the second ring gear is preferably smaller than the first ring gear. This means that further speed reduction can be achieved in a relatively small installation space. In particular, this can create a prerequisite for the use of relatively high-speed DC motors. The first ring gear preferably meshes with the output pinion of the drive motor.

[0036] In particular, in the first embodiment of the gear transmission assembly, the first driven element can be formed by the sun shaft. This allows a lower transmission ratio of the first driven element relative to the drive element than the second driven element, while maintaining a compact design of the gear transmission assembly.

[0037] In particular, in an alternative first embodiment of the invention, the first driven element can be formed by an additional shaft different from the sun shaft.

[0038] The transmission ratio of the additional shaft to the drive element can be different than that of the sun shaft. In particular, the transmission ratio of the additional shaft to the drive element can be lower than that of the sun shaft. As a result, the rotational speed of the additional shaft can be higher than that of the sun shaft. With the additional shaft, a greater rotational speed difference between the first driven element and the second driven element can be achieved. As a result, the running gap can be traversed more quickly on the part of the brake actuator.

[0039] The additional shaft is preferably connected to an additional pinion in a rotationally fixed manner, which meshes with the first toothed ring. This means that a transmission ratio of the additional shaft relative to the drive element which differs from the transmission ratio of the sun shaft can be realized in a simple and space-saving and component-saving manner. Particularly preferably, the additional pinion is formed in one piece with the additional shaft. The additional pinion can be in the form of a tooth segment. It can be very advantageous if the additional pinion engages with a wheel rotation angle of less than 360°.

[0040] Particularly preferably, the sun shaft is designed as a hollow shaft, and the additional shaft is arranged in the sun shaft. In particular, the additional shaft can completely pass through the sun shaft, so that the additional shaft can extend beyond the sun shaft in two directions along the rotation axis of the sun shaft. This arrangement can achieve the advantages associated with the additional shaft in a smaller installation space. In addition, the remaining structure of the gear transmission assembly can also be designed to be similar to the structure of an embodiment without an additional shaft. This is particularly advantageous from a manufacturing perspective.

[0041] A brake actuator designed according to the invention, in particular a service brake actuator for a motor vehicle, in particular a passenger car, has a gear transmission assembly as described above. The brake actuator preferably comprises an electric motor, in particular a DC motor, driving a drive element. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The exemplary embodiments of the present invention are described by the following drawings. In the drawings,

[0043] Figure 1 shows a schematic diagram of a brake actuator with an exploded view of a first exemplary embodiment of a gear transmission assembly;

[0044] Figure 2 Show Figure 1 A cross-sectional view of the brake actuator shown, wherein section BB is marked;

[0045] Figure 3 Show Figure 1 The brake actuator shown is based on Figure 2 BB section view of the marked section;

[0046] Figure 4 a perspective view showing a gear train of a second exemplary embodiment of a gear transmission assembly;

[0047] Figure 5 shows a partial cross-section of a second exemplary embodiment of a gear transmission assembly;

[0048] Figure 6 shows a schematic diagram of a brake actuator with an exploded view of a third exemplary embodiment of a gear transmission assembly;

[0049] Figure 7 Show Figure 6a top view of the illustrated exemplary embodiment, with section AA marked; and

[0050] Figure 8 Show Figure 6 The brake actuator shown is based on Figure 7 AA section view of the marked section. DETAILED DESCRIPTION

[0051] Figures 1 to 8 1 and 2 are different views of different exemplary embodiments. For the sake of clarity, not all reference numerals are used in every figure. Identical components with the same function are given the same reference numerals.

[0052] Figure 1 A brake actuator 10 is shown for a service brake of a motor vehicle, in particular a passenger car. Figure 2 is a cross-sectional view of a brake actuator 10. The brake actuator 10 comprises a first exemplary embodiment of a gear transmission assembly 12 and a DC motor 14. The gear transmission assembly 12 comprises a planetary gear set 16, which comprises a planetary gear carrier 18, three planetary gears 20, and a sun pinion 22, which are arranged on the planetary gear carrier 18 and are arranged in a rotationally fixed manner on a sun shaft 26 having an axis of rotation 24. The planetary gear carrier 18 is mounted via a sliding bearing 27. Figure 1 and Figure 2 In the exemplary embodiment shown, the teeth of the sun pinion 22 are machined from the sun shaft 26. The sun pinion 22 meshes with the planetary gears 20. To achieve the function of the ring gear, the housing 28 of the gear transmission assembly 12 may have internal teeth 30 that mesh with the planetary gears 20.

[0053] The gear transmission assembly 12 further comprises a drive element 33 designed as a drive gear 32. The drive gear 32 is designed as a double gear having a first gear ring 32a and a second gear ring 32b connected to the first gear ring 32a in a rotationally fixed manner. The diameter of the second gear ring 32b is smaller than that of the first gear ring 32a. In particular, Figure 2 As can be seen in FIG. 1 , the first gear ring 32 a meshes with the output pinion 34 of the driven DC motor 14. Due to the diameter ratio of the first gear ring 32 a to the output pinion 34, a gear reduction occurs. The second gear ring 32 b meshes with a sun gear 35 arranged on the sun shaft 26. The sun gear 35 is arranged on the sun shaft 26 in a rotationally fixed manner. The diameter of the second gear ring 32 b is smaller than the sun gear 35, so that a further reduction can be achieved. Therefore, the planetary gear set is driven via the sun shaft 26 and the sun pinion 22.

[0054] The gear transmission assembly 12 also includes Figure 1 and Figure 2In the first exemplary embodiment shown, a first driven element 36 is formed by the sun shaft 26 and a second driven element 38 is formed by the planetary gear carrier 18. When the gear transmission assembly 12 is in operation, the rotational speed and torque that can be obtained by the sun shaft 26 are different from the rotational speed and torque that can be obtained by the planetary gear carrier 18, respectively. Therefore, the transmission ratio of the first driven element 36 to the second driven element 38 is different relative to the drive element 33. The gear transmission assembly 12 is configured so that during operation, the sun shaft 26 has a higher rotational speed and a lower torque than the planetary gear carrier 18. In addition, the sun shaft 26 and the planetary gear carrier 18 are connected to the drive gear 32 so that they have the same direction of rotation.

[0055] The gear transmission assembly 12 also includes Figures 1 to 3 The sun shaft 26 can be driven by the gear output element 40 shown. Figure 1 and Figure 2 The first clutch 42 shown in FIG. 1 is coupled to the gear output element 40, which is designed as a torque limiting clutch. The planetary carrier 18 can be coupled to the gear output element 40 via a second clutch 46, which is designed as a roller one-way clutch 44 and is therefore an overrunning clutch. In particular, in order to be able to establish an operative connection with, for example, a brake pad, the gear output element 40 has spline teeth 48.

[0056] The first clutch 42 has a first drive body 50 and a first driven body 52, wherein the driven body 52 is formed by a gear output element 40. The drive body 50 is designed as a toothed disc 54, which has a toothed profile in the axial direction. The gear output element 40 has a profile that can engage with the toothed disc 54 on the end face 56 facing the toothed disc 54. The toothed disc 54 is connected to the sun shaft 26 in a rotationally fixed manner and is preloaded on the gear output element 40 by a spring element 58 designed as a spring washer 57. Therefore, the first clutch 42 can connect the gear output element 40 to the sun shaft 26 in a force-fit and form-fit connection. The assembly is fixed to the sun shaft 26 in the axial direction by a snap ring 59a, which engages in a locking groove 59b. By preloading and thus, in particular by selecting the spring element 58, a torque limit can be set at which the first clutch 42 separates the gear output element 40 from the sun shaft 26.

[0057] In the exemplary embodiment, the second clutch 46 is designed as a roller-type one-way clutch 44. The roller-type one-way clutch 44 has a second drive body 62 and a second driven body 64, wherein the second drive body 62 is formed by the planetary gear carrier 18 and the second driven body 64 is formed by the gear output element 40. Therefore, the first driven body 52 of the first clutch 42 and the second driven body 64 of the second clutch 46 are identical.

[0058] In particular Figure 3 As shown, the roller-type one-way clutch 44 has a rolling element 66, which rolls on the planetary gear carrier 18 in the non-coupled state, is separated by a clamping spring 68 in the coupled state, and establishes a force-fit connection between the gear output element 40 and the planetary gear carrier 18. This realizes a delay-free switching process from the coupling of the sun shaft 26 and the gear output element 40 to the coupling of the planetary gear carrier 18 and the gear output element 40.

[0059] The gear output element 40 can be arranged in a cylindrical recess 70 of the planetary carrier 18. Therefore, the rotation axis of the gear output element 40 is preferably located on the rotation axis 24 of the sun shaft 26. The cylindrical recess 70 has a side surface 72, which is designed as a drive-side working surface of the second clutch 46. Therefore, the rolling elements 66 of the roller one-way clutch 44 interact directly with the side surface 72.

[0060] Through the above-mentioned components of the first exemplary embodiment, according to the load applied to the gear transmission output element 40 and the rotation direction of the sun shaft 26 and the second planetary gear carrier 18, either the rotation speed and torque of the sun shaft 26 or the rotation speed and torque of the planetary gear carrier 26 can be transmitted to the gear transmission output element 40. Thus, the transmission ratio of the gear transmission output element 40 to the drive gear 32 can be changed according to the load applied to the gear transmission output element 40.

[0061] Special reference Figure 2 , three possible operating states are used to describe the working principle of the first exemplary embodiment of the gear transmission assembly 12.

[0062] In a first possible operating state, the sun shaft 26 and the planetary gear carrier rotate in a first rotational direction. No load is applied to the gear output element 40, or a load that does not exceed the torque limit of the first clutch 42 is applied. The first clutch 42 couples the gear output element 40 to the sun shaft 26. The roller one-way clutch 44 decouples the gear output element 40 from the planetary gear carrier 18, so that the slower rotating planetary gear carrier 18 is "overtaken" by the faster rotating gear output element 40, which is coupled to the sun shaft 26. The gear output element 40 has the rotational speed and torque of the sun shaft 26. This operating state can occur in particular if the brake pad operatively connected to the gear output element 40 passes through the running clearance of the brake (i.e., the distance of contact with the brake disc).

[0063] In a second possible operating state, the sun shaft 26 and the planetary gear carrier 18 also rotate in the first rotational direction. A load exceeding the torque limit of the first clutch 42 is applied to the gear output element 40. The first clutch 42 decouples the gear output element 40 from the sun shaft 26. As soon as the speed of the gear output element 40 drops to the speed of the planetary gear carrier 18, the roller one-way clutch 44 couples the gear output element 40 to the planetary gear carrier 18. The gear output element 40 thus has the speed and torque of the planetary gear carrier 18. This operating state can occur in particular if a brake pad operatively connected to the gear output element 40 is in contact with and presses against a brake disc.

[0064] In a third possible operating state, the sun shaft 26 and the planetary gear carrier 18 rotate in a second rotational direction opposite to the first rotational direction. No load is applied to the gear transmission output element 40 or a load that does not exceed the torque limit of the first clutch 42 is applied. Therefore, the first clutch 42 can couple the gear transmission output element 40 to the sun shaft 26. Due to the principle of the roller one-way clutch 44, the rotational speed of the sun shaft 26 in the second rotational direction is higher than the rotational speed of the planetary gear carrier 18, resulting in the gear transmission output element 40 being coupled to the planetary gear carrier 18. Therefore, the first clutch 42 decouples the gear transmission output element 40 from the sun shaft 16. The gear transmission output element 40 has the rotational speed and torque of the planetary gear carrier 18. This operating state can occur in particular if the brake pad operatively connected to the gear transmission output element 40 is away from the brake disc.

[0065] Figure 4 and Figure 5 A section of a brake actuator 10 is shown having a second exemplary embodiment of a gear transmission assembly 12 . Figures 1 to 3 In the exemplary embodiment shown, the first driven element 36 is formed by an additional shaft 74 which is different from the sun shaft 26, and not by the sun shaft 26. The additional shaft 74 is connected to an additional pinion 76 in a rotationally fixed manner, which meshes with the first ring gear 32a. Particularly preferably, the additional pinion 76 is formed in one piece with the additional shaft 74.

[0066] The additional shaft thus has a lower transmission ratio to the drive gear 32 than the sun shaft 26. The additional shaft 74 therefore rotates at a higher speed than the sun shaft 26. A greater speed difference can be achieved between the first driven element 36 and the second driven element 38, i.e. the planetary carrier 18, by means of the additional shaft 74. As a result, the running gap can be traversed more quickly with respect to the brake actuator 10.

[0067] from Figure 5As can be seen in the figure, in the second exemplary embodiment, the sun shaft 26 is designed as a hollow shaft, and the additional shaft 74 is arranged in the sun shaft 26. In this case, the additional shaft 74 completely passes through the sun shaft 26, so that it protrudes beyond the sun shaft 26 in both directions along the rotation axis 24 of the sun shaft 26. Therefore, the remaining structure of the second exemplary embodiment of the gear transmission assembly 12 and the brake actuator 10 can be the same as the structural design of the first exemplary embodiment of the gear transmission assembly 12. For the sake of clarity, Figure 5 The gear output element 40 and the first clutch 42 and the second clutch 46 (in addition to the planetary carrier 18 as the drive element 62 ) are not shown.

[0068] Figure 6 A brake actuator is shown with a third exemplary embodiment of a gear transmission assembly 12. In this case, unlike the exemplary embodiments explained above, the first clutch 42 is designed as a torque-driven clutch. In this case, the first driven body 50 has a tooth segment 78, which is coupled to the gear transmission output element 40 in a rotationally fixed manner. In addition, the first drive body 50 has a drive tooth 80, such as Figure 7 As shown, the drive tooth 80 can engage with the tooth segment 78. Thus, the tooth segment 78 can be arranged on the circumference of the tooth segment gear 82, for example, at a tooth segment angle 84 that is less than 360°. This means that the tooth segment 78 can only engage with the drive tooth 80 within the tooth segment angle 84. In addition, there is no longer any force transmission between the drive tooth 80 and the tooth segment 78. Thus, the first drive body 50 and the first driven body 52 can be separated from each other. The first drive body 50 can be formed by the first driven element 36.

[0069] Depending on the rotation angle of the first driven body 52, either the speed and torque of the first driven element 36 or the speed and torque of the second driven element 38 can be transmitted to the gear transmission output element 40. Thus, the transmission ratio of the gear transmission output element 40 to the drive element 33 can be changed according to the rotation angle of the first driven body 52.

[0070] In the third exemplary embodiment, the first driven element 36 can be Figure 6 and Figure 8The third clutch 86 shown is coupled to the drive element 33. Thus, the force path comprising the first driven element 36 and the force path comprising the second driven element 38 can be separated from each other on one side of the drive element 33. In the case of rotation in the first direction of rotation, the separation is preferably achieved by the second overrunning clutch 46, which is in principle the same as in the first exemplary embodiment. In the case of rotation in the second direction of rotation (preferably driven by the gear transmission output element 40 in the third exemplary embodiment), the second clutch 46 is closed due to the overrunning clutch principle. The first clutch 42 is designed as an angle-driven clutch, which is usually unable to open in the case of an increase in torque due to a misalignment of the gear transmission assembly 12, which may occur in the first and second exemplary embodiments. Therefore, misalignment of the gear transmission can be avoided by providing the third clutch 86.

[0071] Figure 6 and Figure 8 The third clutch 86 shown is designed as a one-way clutch and is therefore an overrunning clutch. This enables the first driven element 36 to be driven by the drive element 33 in a first rotational direction, while in a second rotational direction, misalignment of the gear transmission assembly 12 can be avoided.

[0072] Special reference Figure 7 and Figure 8 , the working principle of the third exemplary embodiment of the gear transmission assembly 12 is described through three possible operating states.

[0073] In a first possible operating state, the drive element 33 rotates in the first rotational direction, whereby the second driven element 38, which is preferably coupled to the drive element 33 in a rotationally fixed manner, also rotates in the first rotational direction. The third clutch 86 is configured to transfer torque from the drive element 33 to the first driven element 36 in the first rotational direction. The drive teeth 80 of the first drive body 50 engage with the tooth segments 78, so that the first clutch 42 couples the gear output element 40 to the first driven element 36. The second clutch 46 decouples the gear output element 40 from the second driven element 38, whereby the slower rotating second driven element 38 is "overtaken" by the faster rotating gear output element 40. The rotational speed and torque are transferred from the first driven element 36 to the gear output element 40, which also rotates in the first rotational direction. This operating state can occur, for example, if a brake pad operatively connected to the gear output element 40 passes through the running clearance of the brake (i.e., the distance of contact with the brake disc).

[0074] In a second possible operating state, the drive element 33 also rotates in the first rotational direction. The tooth segment 78 has moved to such an extent that there is no longer any force transmission between the drive tooth 80 and the tooth segment 78. Therefore, the first clutch 42 decouples the gear output element 40 from the first driven element 36. As soon as the speed of the gear output element 40 drops at least to the speed of the second driven element 38, the second clutch 46 couples the gear output element 40 to the second driven element 38. The speed and torque are transmitted from the second driven element 38 to the gear output element 40. The gear output element 40 rotates in the first rotational direction. Since the tooth segment 78 is connected to the gear output element 40 in a rotationally fixed manner, in this operating state, the tooth segment 78 continues to rotate at the speed of the gear output element 40. This can in particular prevent the tooth segment 78 from rubbing against the drive tooth 80. This operating state can occur, for example, if a brake pad operatively connected to the gear output element 40 is in contact with a brake disc and is pressed against the brake disc. By means of the gear transmission assembly 12 in the second embodiment, the running clearance of the brake can thus be quickly traversed in a rotationally controllable manner, so that the brake pad is pressed against the brake disc with a high torque and a short path.

[0075] In the third possible operating state, the gear transmission output element 40 rotates in a second rotational direction opposite to the first rotational direction. For example, this operating state can occur if the brake pad operatively connected to the gear transmission output element 40 is away from the brake disc. The gear transmission assembly 12 is preferably driven by the gear transmission output element 40. This can be achieved, for example, by designing the brake using the gear transmission assembly 12 so that when the brake is locked, the removal of the brake pad from the brake disc is driven by the release of the preload introduced into the brake. According to the principle of the second overrunning clutch 46, the second clutch 46 in this case couples the gear transmission output element 40 to the second driven element 38 in the second rotational direction. The corresponding rotation is transmitted to the drive element 33. In addition, the tooth segment 78 connected to the gear transmission output element 40 in a torsionally fixed manner is also correspondingly moved back so that it is again engaged with the drive tooth 80 of the first drive body 50. Therefore, the second driven element 38 is driven at a speed different from the speed of the drive element 33. The third clutch 86 separates the first driven element 36 from the drive element 33, thereby avoiding the misalignment of the gear transmission assembly 12.

[0076] Reference numerals list

[0077] 10Brake actuator

[0078] 12 Gear transmission components

[0079] 14DC motor

[0080] 16 planetary gear sets

[0081] 18Planet gear carrier

[0082] 20Planetary gear

[0083] 22 Sun pinion

[0084] 24 Rotation axis

[0085] 26 Sun Axis

[0086] 27 Sliding bearings

[0087] 28 Shell

[0088] 30 internal teeth

[0089] 32 driving gear

[0090] 32a First ring gear

[0091] 32b Second ring gear

[0092] 33 Driving elements

[0093] 34 Output pinion

[0094] 35 Sun gear

[0095] 36First driven element

[0096] 38 Second driven element

[0097] 40 Gear transmission output element

[0098] 42 First Clutch

[0099] 44 roller one-way clutch

[0100] 46 Second Clutch

[0101] 48 spline teeth

[0102] 50 first driving body

[0103] 52 First driven body

[0104] 54 toothed disc

[0105] 56 end face

[0106] 57 Spring washer

[0107] 58 Spring element

[0108] 59a Snap ring

[0109] 59b Locking slot

[0110] 62 Second driving body

[0111] 64 Second follower

[0112] 66 rolling element

[0113] 68 clamping spring

[0114] 70 grooves

[0115] 72 side surface

[0116] 74 additional axes

[0117] 76 Additional pinion

[0118] 78 tooth segment

[0119] 80 driving teeth

[0120] 82 tooth segment gear

[0121] 84 tooth segment angle

[0122] 86 Third clutch.

Claims

1. A gear transmission assembly (12) for a brake actuator (10), comprising the following features: A drive element (33), A first driven element (36), a second driven element (38), and · Gear transmission output element (40), wherein the transmission ratios of the first driven element (36) and the second driven element (38) relative to the driving element (33) are different, wherein the first driven element (36) can be coupled to the gear transmission output element (40) via a first clutch (42), the first clutch (42) comprising a first driving body (50) and a first driven body (52), and The second driven element (38) can be coupled to the gear transmission output element (40) via a second clutch (46), the second clutch (46) comprises a second driving body (62) and a second driven body (64), and the second clutch is designed as an overrunning clutch.

2. The gear transmission assembly according to claim 1, characterized in that: The first clutch (42) is designed as a torque-limiting clutch.

3. The gear transmission assembly according to claim 2, characterized in that: The first drive body (50) is connected to the first driven element (36) in a rotationally fixed manner and is preloaded on the first driven element (52) via a spring element (58).

4. The gear transmission assembly according to claim 3, characterized in that: The first driven body (52) is formed by a gear transmission output element (40).

5. The gear transmission assembly according to claim 4, characterized in that: The first drive body (50) of the first clutch (42) is designed as a toothed disc (54), and the contour of the gear transmission output element (40) can engage with the toothed disc (54) at the end surface (56) facing the toothed disc (54).

6. The gear transmission assembly according to claim 1, characterized in that: The first clutch (42) is designed as a rotational drive clutch.

7. The gear transmission assembly according to claim 6, characterized in that: The first driven body has a toothed segment coupled to the gear transmission output element in a rotationally fixed manner, and the first drive body has a drive tooth that can engage with the toothed segment.

8. The gear transmission assembly according to any one of claims 6 to 7, characterized in that: The first driven element can be coupled to the drive element via a third clutch.

9. The gear transmission assembly according to claim 8, characterized in that: The third clutch is designed as an overrunning clutch.

10. A gear transmission assembly according to any one of the preceding claims, characterised in that The gear transmission assembly (12) includes a planetary gear set (16), and the planetary gear set (16) includes: Planetary gear carrier (18), at least one planetary gear (20) mounted on the planetary gear carrier (18), and A sun pinion (22) which is connected to the sun shaft (26) in a rotationally fixed manner and meshes with the at least one planetary gear (20).

11. The gear transmission assembly according to claim 10, characterized in that: The second driven element (38) is formed by the planet carrier (18).

12. The gear transmission assembly according to claim 11, characterized in that: The second drive body (62) is formed by the planetary carrier (18) and / or the second driven body (64) is formed by the gear output element (40).

13. The gear transmission assembly according to any one of claims 10 to 12, characterized in that: The first driven element (36) is formed by the sun shaft (26).

14. The gear transmission assembly according to any one of claims 10 to 12, characterized in that: The first driven element (36) is formed by an additional shaft (74) different from the sun shaft (26).

15. The gear transmission assembly according to claim 14, characterized in that: The additional shaft (74) and the sun shaft (26) have different transmission ratios relative to the drive element (33).

16. A brake actuator (10), in particular a service brake actuator for a motor vehicle, comprising a gear transmission assembly (10) according to any one of the preceding claims.

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