Housing and frame for electromechanical brake actuator

Abstract

The invention relates to a housing and a frame for an electromechanical brake actuator. A frame is provided for an actuator assembly of a vehicle brake having a housing enclosing a gear stage and an electric motor for transmitting torque to the gear stage. The frame includes a base having a first interface for connection to the gear stage and a second interface for connection to the motor. A protrusion extends outwardly from the first interface for receiving a fastener to secure the base directly to the housing and to transfer a load from a motor to the housing during a braking operation.

Description

Technical Field

[0001] The present invention relates to an electromechanical brake actuator, and more particularly to a housing and a frame for a drive assembly of an actuator. Background Art

[0002] A load-bearing assembly for a brake actuator typically secures and confines working components of an actuator for service brakes and parking brakes, such as an electric motor and a planetary gear stage. Accordingly, the load-bearing assembly helps absorb forces generated during braking, such as vibration forces, torque, and reaction forces resulting from holding a parking brake. Accordingly, it is desirable to provide a load-bearing assembly designed to optimally withstand and / or distribute these operating forces. Summary of the Invention

[0003] In one example, a frame for an actuator assembly for a vehicle brake is provided, the actuator assembly having a housing that encloses a gear stage and an electric motor for transmitting torque to the gear stage. The frame includes a base having a first interface for connection to the gear stage and a second interface for connection to the electric motor. Protrusions extend outwardly from the first interface for receiving fasteners to directly secure the base to the brake caliper housing and transfer loads from the frame and thus from the electric motor and the gear stage to the brake caliper housing during a braking operation.

[0004] In another example, a housing for an actuator assembly for a vehicle brake is provided, the actuator assembly having a gear stage and an electric motor for transmitting torque to the gear stage, the housing including a first part for receiving the gear stage and the electric motor. A second part is fixed to the first part for enclosing the gear stage and the electric motor. The second part is integrally formed with a control assembly for controlling the operation of the electric motor.

[0005] In another example, a method of forming a housing for an actuator assembly for a vehicle brake is provided, the actuator assembly having a gear stage and an electric motor for transmitting torque to the gear stage. The method includes providing a first part for receiving the gear stage and the electric motor. An interface between a wall and a control assembly for controlling the operation of the electric motor is welded to form a second part. The second part is fixed to the first part to enclose the gear stage and the electric motor within the housing.

[0006] Other objects and advantages of the present invention, as well as a more complete understanding, will be obtained from the following detailed description and the accompanying drawings. Brief Description of the Drawings

[0007] Figure 1 is a schematic view of an exemplary, exploded electromechanical brake actuator in accordance with the present invention.

[0008] Figure 2 Is Figure 1 A perspective view of the drive assembly of the actuator.

[0009] Figure 3A Is a top view of the frame for the actuator.

[0010] Figure 3B Is a perspective view of the frame for the actuator.

[0011] Figure 4 Is a perspective view of the first part of the cover for the actuator.

[0012] Figure 5 Is a top view of the second part of the cover.

[0013] Figure 6 Is a bottom view of the second part.

[0014] Figure 7 Is a schematic diagram of the drive assembly directly fixed to the frame.

[0015] Figure 8 Is a schematic diagram of the first part of the cover fixed to the frame.

[0016] Figure 9A Is a schematic diagram of the second part of the cover connected to the first part.

[0017] Figure 9B Is a schematic diagram of the control assembly connected to the cover.

[0018] Figure 10 Is another exemplary actuator, wherein only the frame is fixed to the first part of the housing.

[0019] Figure 11 Is a schematic diagram of the second part of the housing fixed to the first part.

[0020] Figure 12A Is a schematic diagram of another exemplary housing.

[0021] Figure 12B Is Figure 12A A side view of the housing of.

[0022] Figure 12C Is Figure 12A A bottom view of a part of the housing of. Detailed Description

[0023] The present invention relates to an electromechanical brake actuator, and more particularly to a housing and a frame for a drive assembly of an actuator. Figures 1 to 9B Shows an electromechanical brake (EMB) actuator assembly or actuator 10 for a vehicle according to one aspect of the present invention. Refer to Figures 1 to 2, the actuator 10 includes a drive assembly 14 and a control assembly 90 for controlling the drive assembly 14. The drive assembly 14 provides braking force to the vehicle by converting the rotation of the electric motor 20 into the longitudinal movement of the piston 74 in a known manner.

[0024] For this purpose, the electric motor 20 has an output shaft 22 and a gear 24 that can rotate with the output shaft about an axis 26. The planetary gear stage 40 is connected to the output gear 24 via one or more gears 44. As shown, a single gear 44 helps to transfer torque from the output gear 24 to the planetary gear stage 40. The planetary gear stage 40 has a conventional structure centered on an axis 42 and includes a sun gear, planet gears, and a planet carrier connected to the planet gears, which rotates or revolves about the axis 42 in a known manner.

[0025] The planetary gear stage 40 is coupled to a spindle drive 70, which includes a piston 74 and a spindle 72 that can be rotated by the planetary gear stage. The piston 74 can move axially in response to the rotation of the spindle. The piston 74 can be connected to the spindle 72, for example, by a ball ramp assembly, circulating balls, etc., such that the rotation of the spindle about the axis 42 by the planetary gear stage causes the piston to move longitudinally along the axis. Advancing the piston 74 away from the planetary gear stage 40 applies braking force to the vehicle, while retracting the piston towards the planetary gear stage reduces or releases the braking force.

[0026] A support member or reinforcement member 50 is connected to the spindle drive 70 and is thereby indirectly connected to the planetary gear stage 40. Specifically, the spindle drive 70 is rotatably mounted, for example, by bearings, to a central annular hub 52 of the support member 50. Arms 54 extend radially outward from the hub 52. Each arm 54 terminates in an opening 56. As shown, the four arms 54 together have a cross-shaped or T-shaped arrangement. Additional arms 60 extend outward from the hub 52. A shaft 62 extends through the ends of the arms 60 for positioning and rotatably mounting the gear 44.

[0027] Returning to Figure 1 , the control assembly 90 includes conventional components for controlling and monitoring the operation of the drive assembly 14, including the operation of the electric motor 20. This can include, for example, a printed circuit board on which electrical and electronic components are arranged and electrically connected to each other via traces. The electrical and electronic components form a speed regulation unit for regulating the speed of the electric motor 20. A current measurement unit measures the current received by the electric motor 20. A current supply unit supplies electrical energy to the electric motor 20. A temperature measurement unit measures the temperature within the actuator 10. A force measurement unit measures the braking force provided by the actuator 10. A rotational position detection unit monitors the rotational position of the electric motor 20.

[0028] Referring to Figure 3A and Figure 3B, a support member or frame 100 is provided for receiving the planetary gear stage 40 and the electric motor 20. The frame 100 is formed as a single integral piece from a metal such as aluminum. The frame 100 includes a base 102 defining a first interface 106 and a second interface 126. The first interface 106 may be formed as a ring centered on an axis 110. Projections 112 extend outwardly from opposite sides of the ring 106. As shown, a pair of radially opposed projections 112 extend outwardly from the ring 106. Consider more or fewer projections 112 as alternative configurations of the projections.

[0029] Positioning members 114 are provided on each projection 112. As shown, each positioning member 114 is formed as a cylinder extending parallel to the axis 110. Connecting members 120 are circumferentially arranged around the ring 106. In one example, four connecting members 120 are equally spaced apart around the ring 106. The connecting members 120 may be formed as threaded supports.

[0030] The second interface 126 may be formed as a ring defining a centering surface 128 surrounding an axis 130. A flange 132 extends from the base 102 and partially surrounds the second interface 126. Connecting members 134 are circumferentially provided around the ring 126. The connecting members 134 may be formed as projections having a passage extending therethrough. Cylindrical positioning members 136 are provided adjacent each interface 106, 126. A base or journal 140 is provided on the base 102, between and aligned with the axes 110, 130.

[0031] A housing 150 encloses the drive assembly 14 and the frame 100 and includes a first part or base part 152 ( Figure 4 ) and a second part or cover part 190 ( Figure 5 and Figure 6 ). With specific reference to Figure 4 , the first part 152 includes an annular member 154 defining an opening 156. A recess 160 surrounds the opening 156. Recesses 166 extend radially outward from the annular member 154. As shown, the recesses 166 are radially opposed to each other. Openings 170 extend through each recess 166. Openings 172 are provided around the perimeter of the opening 156 and adjacent to the recesses 166.

[0032] The motor cover 180 extends in a direction generally parallel to the depth of the opening 156. The motor cover 180 may be formed as a cylinder closed at one end. A series of recesses or depressions 182 are circumferentially arranged around the end of the motor cover 180. The depressions 182 may be radially opposed to each other.

[0033] The second part 190 ( Figure 5 and Figure 6)It includes a wall 192 which has an open polygonal shape. A peripheral edge 194 extends along the entire perimeter of the wall 192. Protrusions 196 extend outwardly from opposite sides of the wall 192. As shown, the protrusions 196 extend in opposite directions from each other and lie in the same plane. An opening 200 extends through each protrusion 196.

[0034] A partition 197 is integrally formed with the wall 192 and the edge 194 and is generally located at the intersection therebetween. That is to say, the partition 197 is recessed from the top surface of the edge 194 and spans the entire coverage area of the wall 192. In other words, the partition 197 encloses the interior of the wall 192. The wall 192, the edge 194 and the partition 197 are integrally formed as a single composite, for example by injection molding, which reduces the need to fasten separate components together with fasteners (such as screws or adhesives) or by welding. This advantageously reduces the need to provide a separate seal along the partition / wall / edge interface, thereby reducing the complexity of assembly and the number of parts. At the same time, integrally forming the wall 192 and the partition 197 as a single piece without interfaces / connections eliminates the need to provide potting between the perimeter of the partition and the interior of the wall to help join the components together.

[0035] In Figure 7 In one example shown, for assembling the actuator 10, the planetary gear stage 40 is connected to the first interface 106 and the electric motor 20 is connected to the second interface 126. To this end, a fastener 202 extends through an opening 56 in an arm 54 of the support member 50 and into the connecting member 120 to secure the support member and thus fix the planetary gear stage 40 and the spindle drive 70 connected thereto to the frame 100. This firmly fixes the planetary gear stage 40 within the first interface 106 and aligns the axes 42, 110. At the same time, the electric motor 20 extends into the motor cover 180 and the output shaft 22 extends through the second interface 126. The gear 44 is rotatably connected to the base 140 such that the gear 44 meshes with both the gear 24 and the planetary gear stage 40.

[0036] It should be understood that a part of the electric motor 20 is received in the centering surface 128 in a manner that aligns the rotational axis 26 of the electric motor 20 with the axis 130 of the second fastening surface. This helps to keep the axis 26 of the electric motor 20 parallel to the axis 42 of the planetary gear stage 40. Thus, torque can be reliably transmitted from the electric motor 20 to the planetary gear stage 40.

[0037] It should be understood that using a single-piece frame 100 helps to provide a rigid mounting structure for both the planetary gear stage 40 and the electric motor 20. This high stiffness is maintained at the higher temperatures that may occur during operation of the actuator 10.

[0038] Then, the drive assembly 14 and the sub-components of the frame 100 are fixed to the first portion 152 of the housing 150, as Figure 8 shown. Specifically, the frame 100 is oriented with respect to the first portion 152 such that the electric motor 20 extends into the motor cover 180 and the first interface 106 is positioned within the recess 160. This positions the positioning member 114 within the opening 170 of the housing 150. A first seal 210 is provided between the recess 166 and the protrusion 112 in the first portion 152. In one example, the first seal 210 is a standard O-ring or an integrated (two-piece) seal.

[0039] Meanwhile, the opening 122 is aligned with the opening 172, and the connecting member 134 is aligned with the recess 182. Fasteners 204 extend through the aligned openings 122, 172 to directly fix the first interface 106 to the first portion 152 of the housing 150. Additional fasteners 204 extend through the aligned openings 134, 182 to directly fix the second interface 126 to the first portion 152 of the housing 150. The protrusion 184 extends into the positioning member 136.

[0040] Turning to Figure 9A , the one-piece second portion 190 is positioned over the frame 100 such that the positioning member 114 on the frame extends through the opening 200 in the protrusion 196. A second seal 212 is provided on the positioning member 114 on the frame 100, between the positioning member and the protrusion 196 on the wall 192. The wall 192 extends around the remainder of the frame 100 and encircles the remainder of the frame 100 while forming an interface between the perimeter of the wall and the perimeter of the first portion 152. The interface (denoted as "IF1") between the first portion 152 and the second portion 190 of the housing 150 is then welded together, for example, by a welding process.

[0041] Then, the control assembly 90 is connected to the one-piece second portion 190 ( Figure 9B ), without the need for fasteners such as screws or adhesives. Instead, the control assembly 90 is welded, for example, by laser welding, vibration welding, or ultrasonic welding, to the edge 194 in an integrated process while covering the partition 197. To this end, the perimeter of the control assembly 90 and the top surface of the edge 194 are aligned with each other along the interface (denoted as "IF2") and welded together. This advantageously reduces the need to provide a separate seal along the control assembly / edge interface, thereby reducing the complexity of the assembly and the number of parts.

[0042] Since the frame is fixed to the brake caliper using protrusions, the positioning member 114, and the fixing means, the frame 100 is enabled to transfer vibrations and other forces / stresses from the electric motor 20 and the gear stage 40 to the brake caliper via the protrusion 112 ultimately, while avoiding / mitigating any vibration loads from being transferred from the frame to the housing 150 and thus to the control assembly 90.

[0043] In Figure 10 another example shown, the frame 100 is fixed to the first portion 152 of the housing 150 as described above, but the drive assembly 14 is not first attached to the frame. In this example, the control assembly 90 and the second portion 190 are not pre-assembled into a single unit. Instead, further turning to Figure 11 , the wall 192 is positioned separately above the frame 100 such that the positioning member 114 on the frame extends through the opening 200. A second seal 212 is provided on the positioning member 114 on the frame 100, between the positioning member and the protrusion 196 on the wall 192. The wall 192 extends around the remainder of the frame 100 and surrounds the remainder of the frame 100 while forming an interface between the perimeter of the wall and the perimeter of the first portion 152. The first portion 152 and the second portion 190 are then directly and firmly fixed to each other along the interface, for example, by laser welding, epoxy resin, etc.

[0044] Once this is completed, the drive assembly 14 is inserted through the first portion 152 of the cover 150 and directly fixed to the frame 100 in the manner described above. Then the partition 197 (not shown here) is inserted and fixed to the edge 194 along the interface IF, as described above. Finally, as described above, the control assembly 90 is inserted and fixed to the edge 194 along the interface IF2 to enclose the drive assembly 14 and the partition 197 within the housing 150.

[0045] The actuator assembly 10 can be configured to be directly fixed to the remainder of the brake caliper. In Figures 12A to 12C one example shown, the protrusion 196 on the wall 192 is elongated, thus elongating the opening 200. That is, the opening 200 allows the frame 100 (more specifically, the protrusion 112) to slide through the entire depth of the protrusion 196 to be directly connected to the brake caliper 250. This enables the frame 100 to transfer vibrations and other forces / stresses from the electric motor 20 through the protrusion 112 to the brake caliper 250 ultimately, while avoiding / mitigating any vibration loads from being transferred from the frame to the wall 192 and thus to the control assembly. Additionally, this advantageously allows the first portion 152 and the second portion 190 of the housing to be integrally formed as a single piece without the need for fasteners, etc.

[0046] The present invention is advantageous because it allows the load-bearing assembly to re-distribute the reaction forces generated by the drive assembly in a manner that helps to extend the effective life of the load-bearing assembly. To this end, the electric motor is directly mounted to the frame, and thus, the frame provides a robust path for transferring vibration loads during the operation of the electric motor. More specifically, vibration loads on the electric motor, for example, caused by vibrations in the suspension due to road terrain, are transferred to the housing through the protrusions on the frame. Additionally, the direct connection between the frame and the electric motor helps to maintain the motor torque applied during the application of the parking brake.

[0047] What has been described above are examples of the present invention. Of course, it is not possible to describe every conceivable combination of components or methods for the purpose of describing the present invention, but those skilled in the art will recognize that many other combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A frame for an actuator assembly of a vehicle brake, the actuator assembly having a housing that encloses the frame, a gear stage, and an electric motor for transmitting torque to the gear stage, the frame comprising: A base having a first interface for connection to the gear stage and a second interface for connection to the electric motor, wherein projections extend outwardly from the first interface for receiving a plurality of fasteners to directly secure the base to the brake caliper housing and transfer loads from the electric motor to the brake caliper housing during a braking operation.

2. The frame according to claim 1, wherein The projections are integrally formed with the base.

3. The frame according to claim 1, wherein, The projections extend away from each other.

4. The frame according to claim 1, wherein, The projections are radially opposite each other about an axis centered on the first interface.

5. The frame according to claim 1, wherein The base is formed of metal.

6. A housing for an actuator assembly of a vehicle brake, the actuator assembly having a frame for receiving a gear stage and an electric motor for transmitting torque to the gear stage, the housing comprising: A first portion for receiving the frame, the gear stage, and the electric motor; And A separate second portion fixed to the first portion for enclosing the frame, the gear stage, and the electric motor.

7. The housing according to claim 6, wherein, The first portion and the second portion include mating structures for receiving outwardly extending projections on the frame.

8. The housing according to claim 6, wherein, The first portion and the second portion are welded along an interface to seal the interface.

9. The housing according to claim 6, wherein, The first portion and the second portion are welded along an interface to seal the interface.

10. The housing according to claim 6, wherein, The second portion includes an open wall and a partition integrally formed with the wall and enclosing the interior of the wall for enclosing the frame, the gear stage, and the electric motor.

11. The housing according to claim 10, wherein, There is no potting at the intersection between the second portion and the partition.

12. The housing according to claim 7, wherein, The second portion is welded along an interface to a control assembly for controlling the operation of the electric motor.

13. The housing according to claim 12, wherein, The second portion and the control assembly are welded along an interface to seal the interface.

14. The housing according to claim 6, wherein, The second portion includes a wall and projections extending outwardly from the wall for fixing to the frame of the actuator assembly that supports the gear stage and the electric motor.

15. A method of forming a housing for an actuator assembly of a vehicle brake, the actuator assembly having a frame, a gear stage, and an electric motor for transmitting torque to the gear stage, the method comprising: Providing a first portion that receives the frame, the gear stage, and the electric motor; Providing a second portion having an open wall and a partition integrally formed with the wall and enclosing the interior of the wall; And Welding the interface between the first portion and the second portion to enclose the frame, the gear stage, and the electric motor within the housing.

16. The method according to claim 15, the method further comprising welding the interface between the second portion and a control assembly for controlling the operation of the electric motor.

17. The method according to claim 16, wherein, Welding the interface includes one of the following: laser welding the interface; ultrasonic welding the interface; and vibration welding the interface.

18. The method according to claim 15, wherein Welding the interface includes welding the interface between the first part and the second part.

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