Electronic brake actuator, especially electronic parking brake actuator

Abstract

Electronic brake actuator (100) including a gearbox housing (10), a gearbox cover (20), a motor (30), a first-stage transmission gear assembly (40), a second-stage transmission gear assembly (50), a planetary gear transmission assembly (60), and an internal gear ring (13). The internal gear ring is located in a gear chamber (12) of the gearbox body and is press-fitted with a bottom of the gearbox body that corresponds to the gear chamber. At least an internal gear portion of the internal gear ring is manufactured from powder metallurgy or metal like material. The electronic brake actuator provided in the invention designs the internal gear ring as an independent component, which is then fixed inside the gearbox body by means of press-fitting, and the internal tooth portion of the internal gear ring is made of powder metallurgy or metal-like material.

Description

2024P07498Electronic brake actuator, especially electronic parking brake actuatorTechnical Field

[0001] The invention relates to the technical field of vehicle braking technologies, and in particular, for serving as an improved electronic brake actuator, especially electronic parking brake actuator.Background

[0002] The electronic brake actuator includes a motor and a transmission wheel gear mechanism. The transmission wheel gear mechanism reduces an output rotational speed of the motor while increasing an output torque, and transmits the output torque to a brake caliper to achieve a brake function. The transmission mechanism may adopt various transmission methods, such as a belt transmission mechanism, a worm gear transmission mechanism, a spur gear transmission mechanism, a planetary gear transmission mechanism, and the like. To obtain a specific reduction ratio, multi-stage transmission may also be adopted. Compared with other transmission methods, the planetary gear transmission mechanism has advantages of a high reduction ratio, a compact structure, and stable operation.

[0003] Here, an internal gear ring in the brake actuator is configured to mesh with a planetary gear in the planetary transmission mechanism. The existing internal gear ring and a gearbox body are formed by integral injection molding, which results in a relatively low upper limit of torque tolerance for the internal gear ring, rendering it fail to meet the requirements of torque transmission.Summary of the Invention

[0004] An objective of the invention is to provide an electronic brake actuator, which is capable of improving the strength and manufacturing precision of the internal gear, enhancing the stability of the meshing efficiency, and solving a problem of failing to meet the requirements of torque transmission.2024P07498

[0005] According to a first aspect of embodiments of the invention, an electronic brake actuator is provided, including: a gearbox body, the gearbox body comprising a motor accommodation chamber and a gear chamber, wherein the gear chamber is disposed at a front end of the motor accommodation chamber and is in communication with the motor accommodation chamber; a gearbox cover for covering the gearbox body and sealing the gear chamber; a motor assembled in the motor accommodation chamber, the motor having an output shaft extending into the gear chamber, with a first gear fixed on the output shaft of the motor; a first-stage transmission gear assembly comprising a second gear and a third gear coaxially arranged, wherein the second gear meshes with the first gear; a second-stage transmission gear assembly comprising a fourth gear and a sun gear coaxially arranged, wherein the fourth gear meshes with the third gear; a planetary gear transmission assembly comprising a planetary gear carrier, a plurality of planetary gears, and one output spline, wherein the plurality of planetary gears are assembled on a first end surface of the planetary gear carrier, the output spline is assembled on a second end surface of the planetary gear carrier, the first end surface and the second end surface being two opposite surfaces of the planetary gear carrier, the sun gear is located at a central position of the plurality of planetary gears and meshes with each of the plurality of planetary gears, and the output spline extends out along a bottom of the motor accommodation chamber; and an internal gear ring located in the gear chamber and press-fitted with a bottom of the gearbox body that corresponds to the gear chamber, wherein the plurality of planetary gears are located within the internal gear ring and separately mesh with the internal gear ring, and at least an internal tooth portion of the internal gear ring is made of powder metallurgy or metal-like material that can involve semi metal material.2024P07498

[0006] A further improvement of the electronic brake actuator of the invention is that the internal gear ring is made of powder metallurgy or metal-like material that can involve semi metal material.

[0007] A further improvement of the electronic brake actuator of the invention is that the gearbox body is provided with an annular step in a region of the gear chamber that corresponds to the second-stage transmission gear assembly, and the internal gear ring is press-fitted onto the annular step.

[0008] A further improvement of the electronic brake actuator of the invention is that the internal gear ring is provided with a mounting portion, and a surface of the annular step is provided with a mating portion, the internal gear ring being press-fitted into the gear chamber by mating assembly of the mounting portion and the mating portion.

[0009] A further improvement of the electronic brake actuator of the invention is that at least two mounting portions are provided, and a number of mating portions is the same as a number of mounting portions and the mating portions are in one-to- one correspondence with the mounting portions.

[0010] A further improvement of the electronic brake actuator of the invention is that the mounting portions are locating posts disposed on the internal gear ring, the locating posts extending out from a press-fitting surface of the internal gear ring, wherein the press-fitting surface is one end surface of the internal gear ring in a direction of a central axis thereof, and the mating portions are locating holes on the surface of the annular step.

[0011] A further improvement of the electronic brake actuator of the invention is that a portion of each of the locating posts protrudes beyond a circumferential side surface of the internal gear ring, and a side surface of the annular step is correspondingly provided with a recessed portion to accommodate the protruding portion of the locating post.2024P07498

[0012] A further improvement of the electronic brake actuator of the invention is that the mounting portions are locating holes disposed on the internal gear ring, and the mating portions are locating posts disposed on the surface of the annular step.

[0013] A further improvement of the electronic brake actuator of the invention is that in a direction of a central axis of the internal gear ring, internal teeth of the internal gear ring do not protrude beyond end surfaces on both sides of the internal gear ring.

[0014] A further improvement of the electronic brake actuator of the invention is that a central axis of the first gear is parallel to a central axis of the planetary gear transmission assembly and a central axis of the second-stage transmission gear assembly, and the central axis of the second-stage transmission gear assembly is coincident with the central axis of the planetary gear transmission assembly.

[0015] In the electronic brake actuator provided in the invention, the internal gear ring is designed as an independent component, which is then fixed inside the gearbox body by means of press-fitting, and the internal tooth portion of the internal gear ring is made of powder metallurgy or other metal-like material. This satisfies design schemes requiring different parameters, and can enhance the strength and manufacturing precision of the internal gear ring, and improve the stability of meshing efficiency, thereby enabling expansion of the range of compatible torque.Brief Description of Drawings

[0016] The invention is described in detail below with reference to the accompanying drawings via exemplary embodiments. In the accompanying drawings:FIG. 1 illustrates an exploded view of an electronic brake actuator provided in an embodiment of the invention;FIG. 2 illustrates a cross-sectional view of an electronic brake actuator provided in an embodiment of the invention;2024P07498FIG. 3 illustrates a schematic structural diagram of a first-stage transmission gear assembly provided in an embodiment of the invention;FIG. 4 illustrates a schematic structural diagram of a second-stage transmission gear assembly provided in an embodiment of the invention;FIG. 5 illustrates a schematic structural diagram of a planetary gear transmission assembly provided in an embodiment of the invention; andFIG. 6 illustrates a schematic assembly diagram of a gearbox body and an internal gear ring provided in an embodiment of the invention.The drawings are schematic and not necessarily drawn to scale. Furthermore, they only illustrate those parts necessary for elucidating the invention, while other parts may be omitted or only briefly mentioned. That is, in addition to the components shown in the drawings, the invention may also include other components. The drawings are only schematic and are not necessarily drawn in proportion, and they show only most essential parts as far as necessary for the purpose of clarifying the invention, while other parts may be omitted or referred to. That is, in addition to the components shown in the drawings, the invention may also include other components. The present inventions disclosure is neither limited nor bound alone concerning the claimed inventive actuator structure as such alone but also contains and claims for improved manufacturing skills with manufacturing process issues in terms for manufacturing single components but also at least implicitly contains valuable improvement concerning high efficient automotive industrial component manufacturing i.e. including efficient actuator assembly process improvement. Finally an improved automotive wheel brake assembly that is comprising the above explained electronic brake actuator is included under the disclosure of

[0017] the present invention. The invention may be implemented in various embodiments. For example the invention is serving and performing in / for automotive electric service brakes as electronic actuator. Then the invention is included in electric service wheel brakes. Another embodiment is possible for automotive electric parking brakes. Then the invention is included and mounted to electric parking wheel brakes. Finally the invention may be mounted / included in the so-called combined wheel brakes that combine the functions of service brake and the parking brake in one wheel2024P07498 brake system. The electronic parking brake can be configured as integrated, preferably currentless and self locked, electronic parking brake system. Then the self locking parking brake function can preferably be implemented with integration of a frictionally self locked spindledrive module which can be held and housed in the wheel brakes caliper module. In preferable alternative embodiment the electronic parking brake can comprise a switchable park lock unit PLU which can be configured as an extra unit that may be integrated or received in total or partly in the actuator housing or in the actuator cover and wherein the PLU can comprise a switchable and translationally movable park lock element with electric park lock actuator for releasable locking cooperation of the said park lock element with at least one rotating gear drivetrain element of the actuator.Detailed Description

[0018] The following describes implementations of the invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the invention from contents disclosed in this specification. Although the description of the invention will be introduced in conjunction with a preferred embodiment, it does not mean that features of the invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the invention. In order to provide a deeper understanding of the invention, the following description includes many specific details. The invention can also be implemented without these details. Furthermore, in order to avoid confusion or blurring key points of the invention, some specific details will be omitted from the description. It should be explained that where no conflict arises, embodiments in the invention may be combined, and features in embodiments may be combined.

[0019] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.2024P07498

[0020] In the description of this embodiment, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "inner", etc., is based on the orientation or positional relationship shown in the accompanying drawings, or the customary placement orientation or positional relationship when the invention product is in use. This is only for the purpose of facilitating the description of the invention and simplifying the description, rather than to indicate or imply that the referred apparatus or element must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the invention.

[0021] In addition, terms such as “first” and “second” are merely used for descriptive purposes, and must not be interpreted as indicating or implying relative importance.

[0022] In the description of this embodiment, it should be further noted that, unless otherwise clearly specified and defined, terms such as “arrange”, “connected”, and “connect” should be interpreted in a broad sense, for example, they may indicate a fixed connection, or a removable connection, or an integral connection; they may indicate a mechanical connection, or an electrical connection; they may indicate a direct connection, or an indirect connection via an intermediate medium, or internal communication between two elements. Those of ordinary skill in the art can interpret the specific meaning of the above-mentioned terms in this embodiment according to particular circumstances.

[0023] In order to make the purpose, technical solutions, and advantages of the invention clearer, implementations of the invention will be described in further detail below with reference to the accompanying drawings.

[0024] FIG. 1 illustrates an exploded view of an electronic brake actuator provided in an embodiment of the invention; FIG. 2 illustrates a cross-sectional view of an electronic brake actuator provided in an embodiment of the invention; FIG. 3 illustrates a schematic structural diagram of a first-stage transmission gear assembly provided in an embodiment of the invention; FIG. 4 illustrates a schematic structural diagram of a second-stage transmission gear assembly provided in an embodiment of2024P07498 the invention; and FIG. 5 illustrates a schematic structural diagram of a planetary gear transmission assembly provided in an embodiment of the invention.

[0025] With reference to FIG. 1 to FIG. 5, an electronic brake actuator of an embodiment of the invention includes a gearbox body 10, a gearbox cover 20, a motor 30, a first-stage transmission gear assembly 40, a second-stage transmission gear assembly 50, a planetary gear transmission assembly 60, and an internal gear ring 13.

[0026] The gearbox body 10 includes a motor accommodation chamber 11 and a gear chamber 12. The gear chamber 12 is disposed at a front end of the motor accommodation chamber 11 and is in communication with the motor accommodation chamber 11. The gear chamber 12 is configured to accommodate the first-stage transmission gear assembly 40, the second-stage transmission gear assembly 50, the planetary gear transmission assembly 60, and the internal gear ring 13. Herein, the front end of the motor accommodation chamber 11 is an end where an output shaft of the motor 30 is located. The gearbox cover 20 is configured to cover the gearbox body 10 and seal the gear chamber 12.

[0027] The motor 30 is assembled in the motor accommodation chamber 11, the motor 30 having an output shaft extending into the gear chamber 12, with a first gear 31 fixed on the output shaft of the motor 30. The first gear 31 is configured to mate with the first-stage transmission gear assembly 40. A rear end of the motor accommodation chamber 11 is provided with a motor cover 32. The motor cover 32 is assembled at the rear end of the motor accommodation chamber 11 to seal the motor 30 within the motor accommodation chamber 11. A wave spring 33 of the motor 30 is further disposed between the motor cover 32 and the motor 30. The axial clearance of the motor 30 is adjusted by means of the wave spring 33 of the motor 30.

[0028] The first-stage transmission gear assembly 40 includes a second gear 41 and a third gear 42 coaxially arranged, where the second gear 41 meshes with the first gear 31. In the embodiment of the invention, a diameter of the second gear 42 is larger than a diameter of the third gear 41, a first pin shaft 43 is provided on a central axis of the second gear 41, and the third gear 42 is assembled on the first pin shaft 43, thereby enabling the third gear 42 to rotate synchronously with the second gear 41. The second gear 41, the first pin shaft 43, and the third gear 42 may be formed through integral2024P07498 injection molding. The second gear 41 and the third gear 42 may also be fixed to the first pin shaft 43 by means of press-fitting, or either one of the gears may be injection- molded taking the first pin shaft 43 as the shaft, which is not specifically limited herein.

[0029] The first pin shaft 43 extends beyond the third gear 42 for mating and press-fitting with a locating pin hole on the gearbox body 10. The locating pin hole is located at a bottom of the gear chamber 12. When the first-stage transmission gear assembly 40 is assembled, the third gear 42 is farther from the gear cover body 20 than the second gear 41. Herein, through the meshing of the second gear 41 with the first gear 31, when the motor 30 drives the first gear 31 to rotate, the second gear 41 is synchronously driven to rotate, thereby causing the first-stage transmission gear assembly 40 to rotate.

[0030] The second-stage transmission gear assembly 50 includes a fourth gear 51 and a sun gear 52 coaxially arranged, where the fourth gear 51 meshes with the third gear 42 to cause the second-stage transmission gear assembly 50 to rotate via transmission by the third gear 42. The second-stage transmission gear assembly 50 further includes a second pin shaft 53. The fourth gear 51 and the sun gear 52 are fixed on the second pin shaft 53. Herein, the second pin shaft 53 extends beyond the fourth gear 51 to fit into a shaft hole of the gearbox cover 20. A diameter of the fourth gear 51 is larger than a diameter of the sun gear 52. The fourth gear 51, the second pin shaft 53, and the sun gear 52 may be integrally injection-molded. The fourth gear 51 and the sun gear 52 may also be fixed to the second pin shaft 53 by means of press-fitting, or either one of the gears maybe injection-molded taking the first pin shaft 43 as the shaft, which is not specifically limited herein.

[0031] In this embodiment, since the sun gear 52 is configured to mesh with planetary gears and requires relatively high output torque, the sun gear 52 is configured to be made of powder metallurgy or metal-like material that can involve semi metal material. The fourth gear 51 may be injection-molded taking the second pin shaft 53 as the shaft, and the sun gear 52 is press-fitted onto the second pin shaft 53.

[0032] The planetary gear transmission assembly 60 includes a planetary gear carrier 61, a plurality of planetary gears 62, and one output spline 63. The plurality of planetary gears 62 are assembled on a first end surface 611 of the planetary gear2024P07498 carrier 61, the output spline 63 is assembled on a second end surface 612 of the planetary gear carrier 61, the first end surface 611 and the second end surface 612 being two opposite surfaces of the planetary gear carrier 61, the sun gear 52 is located at a central position of the plurality of planetary gears 62 and meshes with each of the plurality of planetary gears 62, and the output spline 63 extends out along a bottom of the motor accommodation chamber 11.

[0033] In the embodiment of the invention, the planetary gear carrier 61 has a frustum-shaped structure. The planetary gear transmission assembly 60 includes four planetary gears 62, and the first end surface 611 of the planetary gear carrier 61 is uniformly provided with four planetary gear shafts 64. The four planetary gears 62 and the four planetary gear shafts 64 are assembled in a one-to-one correspondence, enabling the four planetary gears 62 to be revolvably assembled on the first end surface 611 of the planetary gear carrier 61.

[0034] Herein, the planetary gear carrier 61, the four planetary gear shafts 64, and the output spline 63 are integrally injection-molded. In another embodiment, the output spline 63 may be made of powder metallurgy or metal-like material that can involve semi metal material, and then the planetary gear carrier 61 and the planetary gear shafts 64 are injection-formed based on the output spline 63. The output spline 63 is located at a central position of the planetary gear carrier 61. Specifically, a central axis of the output spline 63 is coincident with a central axis of the planetary gear carrier 61.

[0035] The internal gear ring 13 is disposed in the gear chamber 12. The plurality of planetary gears 62 are located inside the internal gear ring 13 and separately mesh with the internal gear ring 13. After the first-stage transmission gear assembly 40, the second-stage transmission gear assembly 50, and the planetary gear transmission assembly 60 are assembled, the sun gear 52 meshes with each of the four planetary gears 62 to drive the four planetary gears 62 to rotate. The four planetary gears 62 revolve through meshing with the internal gear ring 13, thereby driving the planetary gear carrier 61 to rotate.

[0036] After the first-stage transmission gear assembly 40, the second-stage transmission gear assembly 50, and the planetary gear transmission assembly 60 are2024P07498 assembled, a central axis of the first gear 31 is parallel to a central axis of the planetary gear transmission assembly 60 and a central axis of the second-stage transmission gear assembly 50, and the central axis of the second-stage transmission gear assembly 50 is coincident with the central axis of the planetary gear transmission assembly 60. The transmission combination relationship of the invention is: the second gear 41 meshes with the first gear 31, the fourth gear 51 meshes with the third gear 42, the sun gear 52 meshes with the four planetary gears 62, and the four planetary gears 62 mesh with the internal gear ring 13.

[0037] As shown in FIG. 1 to FIG. 5 in conjunction with FIG. 6, the internal gear ring 13 is located in the gear chamber 12 and press-fitted to a bottom of the gearbox body 10 that corresponds to the gear chamber 12, the plurality of planetary gears 62 are located within the internal gear ring 13 and separately mesh with the internal gear ring 13, and the plurality of planetary gears 62 revolve through meshing with the internal gear ring 13, thereby driving the planetary gear carrier 61 to rotate. The internal gear ring 13 is separately designed and is fixed inside the gearbox body 10 by means of linear press-fitting, thereby enabling the internal gear ring 13 to be replaced according to requirements, including but not limited to in terms of material and structure.

[0038] A conventional internal gear ring 13 and the gearbox body 10 are integrally injection-molded, which results in a relatively low upper limit of torque tolerance for the internal gear ring 13, rendering it fail to meet the requirements of torque transmission. In the invention, at least the internal tooth portion of the internal gear ring 13 is made of powder metallurgy or metal-like material that can involve semi metal material, thereby enhancing the output torque of the internal gear ring 13.

[0039] In an embodiment, the internal gear ring 13 is made of powder metallurgy or metal-like material that can involve semi metal material, thereby improving the strength and manufacturing precision of the internal gear, and further enhancing the output torque of the internal gear ring 13. By enhancing the meshing precision between the internal gear ring 13 and the plurality of planetary gears 62, the NVH (Noise, Vibration, Harshness) performance of the product is improved. The internal gear ring 13 of the invention can precisely adapt to different torque2024P07498 requirements by replacing powder metallurgy or metals of different strengths, thereby achieving improved economy.

[0040] Herein, in a direction of a central axis of the internal gear ring 13, internal teeth of the internal gear ring 13 do not protrude beyond end surfaces on both sides of the internal gear ring 13. In the embodiment of the invention, in the direction of the central axis of the internal gear ring 13, a dimension of the internal teeth of the internal gear ring 13 is equal to a dimension between the end surfaces on both sides of the internal gear ring 13, that is, a tooth width of the internal gear ring 13 is consistent with a thickness of the internal gear ring 13. Furthermore, the internal gear ring 13 may also be adjusted in tooth number design according to requirements, thereby facilitating the creation of design schemes with different parameters without requiring new mold making.

[0041] The gearbox body 10 is provided with an annular step 14 in a region of the gear chamber 12 that corresponds to the second-stage transmission gear assembly 50. That is, the second-stage transmission gear assembly 50 is disposed above the annular step 14. The internal gear ring 13 is press-fitted onto the annular step 14, thereby fixing the internal gear ring 13 inside the gearbox body 10.

[0042] The internal gear ring 13 is provided with mounting portions 131, and the surface of the annular step 14 is provided with mating portions 121. The internal gear ring 13 is press-fitted into the gear chamber 12 by mating assembly of the mounting portions 131 and the mating portions 121. Herein, to ensure the stability of the internal gear ring 13 and avoid torsion during transmission, at least two mounting portions 131 are provided, and a number of the mating portions 121 is the same as a number of mounting portions 131 and the mating portions are in one-to-one correspondence with the mounting portions 131. In the drawings of the invention, there are two mounting portions 131, which are disposed on two opposite sides of the internal gear ring 13. In other embodiments, there may be multiple mounting portions 131, which are uniformly disposed on the internal gear ring 13.

[0043] In an embodiment, as shown in FIG. 6, the mounting portions 131 are locating posts disposed on the internal gear ring 13, the locating posts extending out from a press-fitting surface of the internal gear ring 13, where the press-fitting surface2024P07498 is one end surface of the internal gear ring 13 in a direction of a central axis thereof, and the mating portions 121 are locating holes on the surface of the annular step 14. After the internal gear ring 13 is assembled, the press-fitting surface abuts against the surface of the annular step 14. Furthermore, the other end surface of the internal gear ring 13 that is opposite to the press-fitting surface serves as a reference surface, which is used for linear press-fitting. The internal gear ring 13 and the gearbox body 10 are generally assembled by means of an interference fit to ensure the stability of the fixation of the internal gear ring 13.

[0044] Due to space constraints within the gear chamber 12, a radial dimension of the internal gear ring 13 cannot be designed excessively large. However, to further enhance the reliability of fixation, the invention designs a locating post of the internal gear ring 13 such that a portion of the locating post protrudes beyond a circumferential side surface of the internal gear ring 13. Correspondingly, a side surface of the annular step 14 is correspondingly provided with a recessed portion to accommodate the protruding portion of the locating post, thereby being more conducive to locating of the internal gear ring 13.

[0045] In yet another embodiment, not shown in the drawings, the mounting portions 131 are locating holes disposed on the internal gear ring 13, and the mating portions 121 are locating posts disposed on the surface of the annular step 14, thereby enabling the internal gear ring 13 to be press-fitted into the gearbox body 10 through mating of the locating posts and the locating holes.

[0046] The working principle of the invention is as follows: the motor 30 drives the first gear 31 to rotate, the first gear 31 drives the second gear 41 to rotate through meshing, the second gear 41 drives the third gear 42 to rotate, the third gear 42 drives the fourth gear 51 to rotate through meshing, the fourth gear 51 drives the sun gear 52 to rotate, the sun gear 52 drives the four planetary gears 62 to spin through meshing, the four planetary gears 62 revolve through meshing with the internal gear ring 13, driving the planetary gear carrier 61 to rotate, and the planetary gear carrier 61 drives the output spline 63 to rotate, ultimately outputting power.

[0047] In the electronic brake actuator provided in the invention, the internal gear ring is designed as an independent component, which is then fixed inside the2024P07498 gearbox body by means of press-fitting, and the internal tooth portion of the internal gear ring is made of powder metallurgy or metal-like material that can involve semi metal material. This satisfies design schemes requiring different parameters, and can enhance the strength and manufacturing precision of the internal gear ring, and improve the stability of meshing efficiency, thereby enabling expansion of the range of compatible torque.

[0048] Although the invention has been illustrated and described with reference to certain preferred implementations of the invention, those of ordinary skill in the art should understand that the above content is a further detailed description of the invention in conjunction with specific implementations, and it cannot be determined that the specific implementation of the invention is limited to these descriptions. Those skilled in the art can make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

2024P07498Patent claims1. An electronic brake actuator, especially electronic parking brake actuator, comprising: a gearbox body, the gearbox body comprising a motor accommodation chamber and a gear chamber, wherein the gear chamber is disposed at a front end of the motor accommodation chamber and is in communication with the motor accommodation chamber; a gearbox cover for covering the gearbox body and sealing the gear chamber; a motor assembled in the motor accommodation chamber, the motor having an output shaft extending into the gear chamber, with a first gear fixed on the output shaft of the motor; a first-stage transmission gear assembly comprising a second gear and a third gear coaxially arranged, wherein the second gear meshes with the first gear; a second-stage transmission gear assembly comprising a fourth gear and a sun gear coaxially arranged, wherein the fourth gear meshes with the third gear; a planetary gear transmission assembly comprising a planetary gear carrier, a plurality of planetary gears, and one output spline, wherein the plurality of planetary gears are assembled on a first end surface of the planetary gear carrier, the output spline is assembled on a second end surface of the planetary gear carrier, the first end surface and the second end surface being two opposite surfaces of the planetary gear carrier, the sun gear is located at a central position of the plurality of planetary gears and meshes with each of the plurality of planetary gears, and the output spline extends out along a bottom of the motor accommodation chamber; and an internal gear ring located in the gear chamber and press-fitted with a bottom of the gearbox body that corresponds to the gear chamber, wherein the plurality of planetary gears are located within the internal gear ring and separately mesh with the internal gear ring, and at least an internal tooth portion of the internal gear ring is made of powder metallurgy or metal-like material that can involve semi metal material.

2. The electronic brake actuator according to claim 1, wherein the internal gear ring is made of powder metallurgy or metal-like material that can involve semi metal material.2024P074983. The electronic brake actuator according to claim 1, wherein the gearbox body is provided with an annular step in a region of the gear chamber that corresponds to the second-stage transmission gear assembly, and the internal gear ring is press-fitted onto the annular step.

4. The electronic brake actuator according to claim 3, wherein the internal gear ring is provided with a mounting portion, and a surface of the annular step is provided with a mating portion, the internal gear ring being press-fitted into the gear chamber by mating assembly of the mounting portion and the mating portion.

5. The electronic brake actuator according to claim 4, wherein at least two mounting portions are provided, and a number of mating portions is the same as a number of mounting portions and the mating portions are in one-to-one correspondence with the mounting portions.

6. The electronic brake actuator according to claim 5, wherein the mounting portions are locating posts disposed on the internal gear ring, the locating posts extending out from a press-fitting surface of the internal gear ring, wherein the pressfitting surface is one end surface of the internal gear ring in a direction of a central axis thereof, and the mating portions are locating holes on the surface of the annular step.

7. The electronic brake actuator according to claim 6, wherein a portion of each of the locating posts protrudes beyond a circumferential side surface of the internal gear ring, and a side surface of the annular step is correspondingly provided with a recessed portion to accommodate the protruding portion of the locating post.

8. The electronic brake actuator according to claim 5, wherein the mounting portions are locating holes disposed on the internal gear ring, and the mating portions are locating posts disposed on the surface of the annular step.

9. The electronic brake actuator according to claim 1, wherein in a direction of a central axis of the internal gear ring, internal teeth of the internal gear ring do not protrude beyond end surfaces on both sides of the internal gear ring.2024P0749810. The electronic brake actuator according to claim 1, wherein a central axis of the first gear is parallel to a central axis of the planetary gear transmission assembly and a central axis of the second-stage transmission gear assembly, and the central axis of the second-stage transmission gear assembly is coincident with the central axis of the planetary gear transmission assembly.

11. The electronic brake actuator according to one or several of the claims 1 - 10, wherein the electronic parking brake is integrated thereby comprising a self locking configured spindledrive module that is held and housed in a wheel brake caliper module, or the electronic parking brake comprises a switchable park lock unit PLU that is configured as an extra unit that is held integrated or received in the actuator housing or in the actuator cover and wherein the park lock unit PLU comprises a switchable and translationally movable park lock element that is electrically driven by an electric park lock actuator for performing a releasable park lock cooperation of the said park lock element with at least one rotating gear drivetrain element of the actuator.

12. Industrial manufacturing process for an electronic brake actuator comprising the features of one or more of the claims 1-11.

13. Industrial assembly process for an electronic brake actuator comprising the features of one or more of the claims 1-11.

14. Automotive wheel brake assembly comprising an electronic brake actuator according to the features of one or more of the claims 1-13.

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