Electronic brake actuator

Abstract

The present invention discloses an electronic brake actuator, comprising an upper housing, a lower housing, a planetary carrier, a duplex gear II, an output shaft mounted on the planetary carrier, a center pin mounted on the upper housing, and a first elastic body disposed between the planetary carrier and the lower housing for applying an elastic force to the planetary carrier, and / or a second elastic body disposed between the upper housing and the duplex gear II for applying an elastic force to the duplex gear II. The electronic brake actuator of the present invention eliminates abnormal noise caused by axial impact by providing an elastic body to eliminate or reduce clearances between the numerous components on the planetary gear main shaft.

Description

Technical Field

[0001] The present invention belongs to the technical field of brake systems, and in particular, relates to an electronic brake actuator. Background Art

[0002] In the prior art, electronic brake actuators typically utilize a two-stage fixed-axis gear and a single-stage planetary gear. This planetary gear system, comprising a sun gear, three or more planetary gears, and a planetary carrier, is mounted in a cavity with the passive gear of the second-stage fixed-axis transmission. This axial clearance fit creates a large axial clearance due to the dimensional chain of this clearance, which includes the tolerances of the upper and lower housing cavities, welding accuracy, the height tolerance of the passive gear of the second-stage fixed-axis transmission, and the thickness tolerance of the output shaft assembly. The combined tolerances of these numerous components result in a large axial clearance. Furthermore, the combined mass of these components is substantial. Vibration can easily cause these components to impact the upper and lower housings, generating impact noise. This noise can be heard by customers inside the vehicle when turning or navigating bumpy roads.

[0003] The aforementioned large axial clearance also causes the planetary carrier to tilt when the electronic brake is not in operation. This tilting of the planetary carrier causes the planetary gears to tilt. When the gears just start to rotate, the tilted gear state causes an unstable transmission at startup, resulting in excessive noise.

[0004] Figure 7 The figure shows an existing electronic brake actuator, which includes a two-stage fixed-axis gear and a one-stage planetary gear transmission. The driven gear of the second-stage fixed-axis gear transmission is the double gear II in the figure. In the existing technology, the double gear II often includes the sun gear of the planetary gear transmission mechanism. The sun gear is often made of metal and is overmolded in the plastic gear in the form of an insert.

[0005] The center pin of the duplex gear II and the main axis of the planetary gear system are located on a straight line, and the duplex gear II and the planetary gear system coexist in a cavity surrounded by the upper housing and the lower housing.

[0006] There are two forms of the ring gear of the planetary gear transmission mechanism. The first form is that the ring gear and the lower housing are injection molded together, and the other form is that the ring gear is installed in the lower housing like the planetary gear.

[0007] The above structures have a common feature, that is, the axial clearance cannot be effectively controlled. The reason is that there are too many involved parts and the dimension chain is too long. The dimension chain includes the axial cavity tolerance of the lower and upper shells, the tolerance of the double gear II and the planetary carrier. If the ring gear is in a separated state, the dimension chain also includes the tolerance of the ring gear. The result of such a long dimension chain is that the axial clearance is too large. This part is as shown in the attached Figure 8As shown, the gear set is designed with a clearance fit between the upper and lower shells. The size of the clearance depends on the axial height of the gear set, the axial size of the shell, and the welding depth of the upper shell 1 and the lower shell 7. It involves the processing errors of many parts, and the clearance is difficult to control within a small range.

[0008] Not only is the axial clearance excessively large, but the cavity also has a high weight due to the large number of components: the weight of the duplex gear II, at least three planetary gears, the planetary carrier, and, if the ring gear is separated, the weight of the ring gear as well.

[0009] If the car makes a sharp turn or goes over a bumpy road, the heavy weight and large gaps between so many parts will cause them to vibrate and make a loud noise when impacting the shell. Customers often hear the abnormal noise inside the car and start to complain.

[0010] The output shaft 9 is integrated into the planetary carrier 8. However, there is radial clearance between the output shaft 9 and the brake caliper, as well as significant axial clearance. When not in normal operation, the planetary carrier 8 is tilted. This tilt causes the planetary gears 5 to tilt, causing the meshing state of the planetary gears 5 to differ from the designed state at the start of rotation, resulting in excessive noise during startup. Summary of the Invention

[0011] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an electronic brake actuator, the purpose of which is to eliminate abnormal noise caused by axial impact and excessive noise during startup.

[0012] In order to achieve the above-mentioned objectives, the technical solution adopted by the present invention is: an electronic brake actuator, including an upper housing, a lower housing, a planetary carrier, a double gear II, an output shaft arranged on the planetary carrier, a center pin arranged on the upper housing, a first elastomer arranged between the planetary carrier and the lower housing and used to apply an elastic force to the planetary carrier and / or a second elastomer arranged between the upper housing and the double gear II and used to apply an elastic force to the double gear II.

[0013] The output shaft passes through the first elastic body.

[0014] The center pin passes through the second elastic body.

[0015] The first elastic body is a wave spring, a wave washer, a flat washer or an O-ring.

[0016] The second elastic body is a wave spring, a wave washer, a flat washer or an O-ring.

[0017] The first elastic body is made of metal, rubber or plastic.

[0018] The second elastic body is made of metal, rubber or plastic.

[0019] The planet carrier has at least one annular surface, which rotates around the main shaft of the planetary gear. The annular surface can be a plane or a curved surface, and the first elastic body cooperates with the annular surface.

[0020] The lower shell has a groove for accommodating the first elastic body, and the groove takes the planetary gear main shaft as the rotation center.

[0021] The electronic brake actuator of the present invention can eliminate abnormal noise by arranging an elastic body to eliminate or reduce the gaps between the numerous components on the planetary gear main shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] This manual includes the following drawings, which show the following contents:

[0023] Figure 1 is a cross-sectional view of the electronic brake actuator of the present invention provided with a first elastic body;

[0024] Figure 2 is a cross-sectional view of the electronic brake actuator of the present invention provided with a second elastic body;

[0025] Figure 3 It is a schematic diagram of the structure in which the elastic body is arranged between the mating surface of the planet carrier and the lower housing;

[0026] Figure 4 This is a schematic diagram of the structure in which the elastic body is arranged between the gear and the mating end surface of the upper housing;

[0027] Figure 5 It is an elastomer in the form of a wave spring washer structure;

[0028] Figure 6 It is an elastomer in the form of a flat washer structure;

[0029] Figure 7 is a cross-sectional view of an electronic brake actuator of the prior art;

[0030] Figure 8 Schematic diagram of the gap between the internal gear and the housing of the electronic brake actuator in the prior art

[0031] The markings in the figure are: 1. Upper housing; 2. Center pin; 3. Duplex gear II; 4. Sun gear; 5. Planetary gear; 6. Pin; 7. Lower housing; 8. Planetary carrier; 9. Output shaft; 10. First elastic body; 11. Joint position; 12. Wave washer; 13. Flat washer; 14. Duplex gear I; 15. First driving gear; 16. Motor; 17. Positioning pin; 18. Second elastic body. DETAILED DESCRIPTION

[0032] The following is a further detailed description of the specific implementation methods of the present invention through the description of embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and to facilitate its implementation.

[0033] like Figures 1 to 6 As shown, the present invention provides an electronic brake actuator, including an upper housing 1, a lower housing 7, a planetary carrier 8, a duplex gear I 14, a duplex gear II 3, an output shaft 9 arranged on the planetary carrier 8, a center pin 2 arranged on the upper housing 1, a positioning pin 17 arranged on the upper housing 1, and a first elastic body 10 arranged between the planetary carrier 8 and the lower housing 7 and used for applying an elastic force to the planetary carrier 8 and / or a second elastic body 18 arranged between the upper housing 1 and the duplex gear II 3 and used for applying an elastic force to the duplex gear II 3.

[0034] Specifically, if Figure 1 and Figure 2As shown, the double gear I 14 is mounted on the positioning pin 17, the upper shell 1 is fixedly connected to the lower shell 7, the upper shell 1 and the lower shell 7 constitute the outer shell of the actuator, and the motor, the first driving gear 15, the double gear I 14, the double gear II 3 and the planetary carrier 8 are arranged inside the outer shell. The first driving gear 15 is fixedly arranged on the motor shaft of the motor. The duplex gear I14 is composed of a first driven gear and a second driving gear. The first driven gear is meshed with the first driving gear 15. The first driven gear and the second driving gear are coaxially fixedly connected and the diameter of the first driven gear is larger than the diameter of the second driving gear. The duplex gear II3 is composed of a second driven gear and a third driving gear. The second driven gear is meshed with the second driving gear. The second driven gear and the third driving gear are coaxially fixedly connected and the diameter of the second driven gear is larger than the diameter of the third driving gear. The third driving gear serves as the sun gear 4 of the planetary gear mechanism. The planet carrier 8, the third driving gear, the ring gear and the planetary gears form a planetary gear mechanism. The rotational force generated by the motor is transmitted to the planetary gear mechanism through the first driving gear 15, the duplex gear I14 and the duplex gear II3, and finally the rotational force is transmitted to the brake caliper assembly by the output shaft 9. The positioning pin 17 is cylindrical, with its axis parallel to the axis of the motor. The duplex gear I 14 is mounted on the positioning pin 17 and positioned between the upper housing 1 and the lower housing 7. The planetary carrier 8 is located between the duplex gear II 3 and the lower housing 7. A pin and an output shaft 9 are provided on the planetary carrier 8. The planetary gears 5, which mesh with the duplex gear II 3, are mounted on the pin. The pin and output shaft 9 extend toward opposite sides of the planetary carrier 8, respectively. The pin and output shaft 9 are parallel in axis, and the output shaft 9 is coaxial with the center pin 2. The output shaft 9 is fixedly connected to the planetary carrier 8 at its center and is a splined shaft. Multiple planetary gears 5 are located between the duplex gear II 3 and the planetary carrier 8. All of the planetary gears 5 are distributed around the third driving gear of the duplex gear II 3, which meshes with the planetary gears. The third driving gear serves as the sun gear 4 of the planetary gear mechanism. The center pin 2 is cylindrical, and the duplex gear II 3 is sleeved on the center pin 2.

[0035] like Figure 1As shown, in this embodiment, only the first elastic body 10 is disposed between the planet carrier 8 and the lower housing 7. The second elastic body 18 is not disposed between the upper housing 1 and the duplex gear II 3. The output shaft 9 passes through the first elastic body 10. The first elastic body 10 is sandwiched between the planet carrier 8 and the lower housing 7. The elastic force exerted by the first elastic body 10 on the planet carrier 8 causes the planet carrier 8 to move axially away from the lower housing 7. Movement of the planet carrier 8 drives the planetary gears synchronously. The elastic body exhibits axial elasticity, which serves to eliminate or reduce axial clearance between the planetary gears and the sun gear 4. The planet carrier 8 exerts an axial force on the duplex gear II 3, maintaining its contact with the upper housing 1. The first elastic body 10 can be a wave spring, wave washer, flat washer, or O-ring. The material of the first elastic body 10 can be metal, plastic, or rubber.

[0036] like Figure 1 and Figure 3 As shown, at least one annular area can be found on planet carrier 8, which mates with first elastic body 10. By adding first elastic body 10 between planet carrier 8 and lower housing 7, the axial clearance between duplex gear II 3 and upper housing 1 is also eliminated (no clearance exists at the position indicated by 11). By eliminating the clearance through first elastic body 10, or ensuring a certain axial force, this axial force maintains the planet carrier 8 in its operating state, keeping the output shaft 9 coaxial with the center pin 2, and thus maintaining the parallel position of the planetary gears in the planetary gear system, thus preventing the planetary gears from tilting during initial operation, i.e., during startup.

[0037] When the first elastic body 10 is made of plastic or metal, the first elastic body 10 is preferably a wave spring washer.

[0038] Another option for the first elastic member 10 is to use a rubber member. A rubber-made first elastic member 10 not only fulfills the two aforementioned functions but also provides a shock-absorbing effect, absorbing actuator vibration and thus reducing actuator noise. The first elastic member 10 can be formed in any shape, with flat washers and O-rings being preferred.

[0039] The lower housing 7 has a groove for accommodating the first elastic body 10. The groove has the planetary gear main shaft as the rotation center. The first elastic body 10 is radially limited in the groove and cannot move radially.

[0040] Planet carrier 8 has at least one annular surface, centered about the planetary gear main shaft. This surface can be flat or curved, and the first elastic member 10 mates with this surface. Both the groove and the annular surface ensure stable friction during planet carrier 8's rotation. Unstable friction torque increases torque vibration on output shaft 9. Torque vibration, a type of vibration, can also increase operating noise and even produce unusual sounds.

[0041] like Figure 2 As shown, in this embodiment, only the second elastic body 18 is disposed between the upper housing 1 and the duplex gear II 3. The first elastic body 10 is not disposed between the planet carrier 8 and the lower housing 7. The center pin 2 passes through the second elastic body 18. The second elastic body 18 is sandwiched between the upper housing 1 and the duplex gear II 3. The elastic force exerted by the second elastic body 18 on the duplex gear II 3 causes the duplex gear II 3 to move axially away from the upper housing 1. The movement of the duplex gear II 3 propels the planetary gears to move synchronously. The second elastic body 18 exhibits axial elasticity, which serves to eliminate or reduce axial clearance between the planetary gears and the sun gear 4. The duplex gear II 3 exerts an axial force on the planet carrier 8, maintaining its contact with the lower housing 7. The second elastic body 18 can be a wave spring, wave washer, flat washer, or O-ring. The material of the second elastic body 18 can be metal, plastic, or rubber.

[0042] like Figure 2 and Figure 4 As shown, at least one annular area can be found on the second driven gear of duplex gear II 3, which cooperates with second elastic body 18. Second elastic body 18 is sandwiched between upper housing 1 and the second driven gear of duplex gear II 3. By adding second elastic body 18 between duplex gear II 3 and upper housing 1, the axial clearance between planet carrier 8 and lower housing 7 is also eliminated (no clearance exists at the position shown in Figure 11). Second elastic body 18 eliminates clearance or ensures a constant axial force. This axial force maintains the planet carrier 8 in a consistent operating state, keeping the output shaft 9 coaxial with the center pin 2, and thus maintaining the parallel position of the planetary gears in the planetary gear system. This prevents the planetary gears from tilting during initial operation, i.e., during startup.

[0043] When the second elastic body 18 is made of plastic or metal, the second elastic body 18 is preferably a wave spring washer.

[0044] Another option for the second elastic member 18 is to use a rubber member. This rubber material not only fulfills the two functions mentioned above but also provides a shock-absorbing effect, absorbing actuator vibration and helping to reduce actuator noise. The second elastic member 18 can be made in any shape, with flat washers and O-rings being preferred.

[0045] For the convenience of explanation, the above description describes that the lower shell 7 includes a gear ring. The gear ring has two forms. The first form is that the gear ring and the lower shell 7 are injection molded together, and the other form is that the gear ring is installed in the lower shell 7.

[0046] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described method. Any non-substantial improvements made using the method concepts and technical solutions of the present invention, or any direct application of the above-described concepts and technical solutions to other situations without modification, fall within the scope of protection of the present invention.

Claims

1. An electronic brake actuator comprising an upper housing, a lower housing, a planetary carrier, a double gear II, an output shaft disposed on the planetary carrier, and a center pin disposed on the upper housing, characterized in that: It also includes a first elastic body disposed between the planet carrier and the lower housing and used to apply an elastic force to the planet carrier; The planet carrier is located between the duplex gear II and the lower housing. The first elastic body is sandwiched between the planet carrier and the lower housing. The elastic force exerted by the first elastic body on the planet carrier causes the planet carrier to move axially in a direction away from the lower housing. When the planet carrier moves, it drives the planetary gears to move synchronously. The first elastic body has axial elasticity, which is used to eliminate or reduce the axial clearance between the planetary gears and the sun gear. The planet carrier exerts an axial force on the duplex gear II to keep the duplex gear II in a close fit with the upper housing. The lower housing has a groove for accommodating the first elastic body. The groove has the planetary gear main shaft as the rotation center. The first elastic body is radially limited in the groove and cannot move radially. The planet carrier has at least one annular surface, which takes the planet gear main shaft as the rotation center. The annular surface is a plane or a curved surface, and the first elastic body cooperates with the annular surface.

2. The electronic brake actuator according to claim 1, characterized in that: The output shaft passes through the first elastic body.

3. The electronic brake actuator according to claim 1, characterized in that: The first elastic body is a wave spring, a wave washer, a flat washer or an O-ring.

4. The electronic brake actuator according to claim 1, characterized in that: The first elastic body is made of metal, rubber or plastic.

5. The electronic brake actuator according to any one of claims 1 to 4, characterized in that: It also includes a second elastic body which is arranged between the upper shell and the double gear II and is used to apply elastic force to the double gear II, and the center pin passes through the second elastic body.

6. The electronic brake actuator according to claim 5, characterized in that: The second elastic body is a wave spring, a wave washer, a flat washer or an O-ring.

7. The electronic brake actuator according to claim 5, characterized in that: The second elastic body is made of metal, rubber or plastic.

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