Patent Application
20250237302
The present invention relates to electromechanical brake actuators and, in particular, relates to a housing and frame for the drive assembly of the actuator.
Carrier assemblies for brake actuators generally secure to and confine the working parts, e.g., motor and planetary gear stage, of the actuator used for service and parking braking. Consequently, the carrier assembly helps to absorb forces created during braking, such as vibrational forces, torque, and reaction forces from holding the parking brake. It is therefore desirable to provide a carrier assembly designed to optimally endure and/or distribute these operational forces.
In one example, a frame is provided for an actuator assembly of a vehicle brake having a housing enclosing a gear stage and a motor for delivering torque to the gear stage. The frame includes a base having a first interface for connecting to the gear stage and a second interface for connecting to the motor. Projections extend outward from the first interface for receiving fasteners to secure the base directly to the housing and transfer loads from the motor to the housing during braking operations.
In another example, a housing for an actuator assembly of a vehicle brake having a gear stage and a motor for delivering torque to the gear stage includes a first part for receiving the gear stage and the motor. A second part is secured to the first part for enclosing the gear stage and the motor. The second part is integrally formed with a control assembly for controlling operation of the motor.
In another example, a method is provided for forming a housing for an actuator assembly of a vehicle brake having a gear stage and a motor for delivering torque to the gear stage. The method includes providing a first part that receivers the gear stage and the motor. An interface between a wall and a control assembly for controlling operation of the motor is fused to form a second part. The second part is secured to the first part to enclose the gear stage and the motor within the housing.
Other objects and advantages and a fuller understanding of the invention will be had from the following detailed description and the accompanying drawings.
The present invention relates to electromechanical brake actuators and, in particular, relates to a housing and frame for a drive assembly of the actuator.
To this end, the motor 20 has an output shaft 22 and a gear 24 rotatable with the output shaft about an axis 26. A planetary gear stage 40 is connected to the output gear 24 via one or more gears 44. As shown, a single gear 44 helps transmit torque from the output gear 24 to the planetary gear stage 40. The planetary gear stage 44 has a conventional construction centered about an axis 42 and including a sun gear, planet gears, and a carrier connected thereto that either rotate about or orbit the axis 42 in a known manner.
The planetary gear stage 40 is coupled to a spindle drive 70 that includes a spindle 72 rotatable by the planetary gear stage and a piston 74, which is axially movable in response to rotation of the spindle. The piston 74 can be connected to the spindle 72 by, for example, a ball ramp assembly, recirculating balls, etc. such that rotation of the spindle by the planetary gear stage 40 about the axis 42 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.
A support or reinforcement member 50 is connected to the spindle drive 70 and thereby indirectly connected to the planetary gear stage 40. In particular, the spindle drive 70 is rotatably mounted, e.g., by a bearing, to a central, ring shaped hub 52 of the support member 50. Arms 54 extend radially outward from the hub 52. Each arm 54 terminates at an opening 56. As shown, four arms 54 collectively have a cross or t-shaped arrangement. An additional arm 60 extends outward from the hub 52. An axle 62 extends through the end of the arm 60 for locating and rotatably mounting the gear 44.
Returning to
Referring to
A locating member 114 is provided on each projection 112. As shown, each locating member 114 is formed as a cylinder extending parallel to the axis 110. Connecting members 120 are circumferentially arranged about the ring 106. In one example, four connecting members 120 are equidistantly spaced around the ring 106. The connecting members 120 can be formed as threaded standoffs.
The second interface 126 can be formed as a ring defining a centering surface 128 encircling an axis 130. A flange 132 extends from the base 102 and partially around the second interface 126. Connecting members 134 are provided circumferentially around the ring 126. The connecting members 134 can be formed as projections having a passage extending therethrough. A cylindrical locating member 136 is provided adjacent each interface 106, 126. A mount or journal 140 is provided on the base 102 between and aligned with the axes 110, 130.
A caliper housing 150 encloses the drive assembly 14 and the frame 100 and includes a first portion or base part 152 (
A motor cover 180 extends in a direction generally parallel to the depth of the opening 156. The motor cover 180 can be formed as a cylinder closed at one end. A series of pockets or recesses 182 are circumferentially arranged about the end of the motor cover 180. The recesses 182 can be diametrically opposed from one another.
The second portion 190 (
A bulkhead 197 is integrally formed with the wall 192 and the rim 194 and located generally at the intersection therebetween. That said, the bulkhead 197 is recessed from the top surface of the rim 194 and spans the entire footprint of the wall 192. In other words, the bulkhead 197 closes the interior of the wall 192. Forming the wall 192, rim 194, and bulkhead 197 integrally as a single, composite piece, e.g., via injection molding, alleviates the need to secure separate components together with fasteners, such as screws or adhesive, or via welding. This advantageously alleviates the need to provide a separate seal along the bulkhead/wall/rim interface(s), thereby reducing the complexity of assembly and the number of parts. At the same time, integrally forming the wall 192 and bulkhead 197 as a single piece without an interface/connection obviates the need to provide potting between the periphery of the bulkhead and interior of the wall to help join the components together.
In one example shown in
It will be appreciated that a portion of the motor 40 is received in the centering surface 128 in a manner that aligns the rotation axis 26 of the motor 20 with the axis 130 of the second fastening surface. This helps keep the axis 26 of the motor 20 parallel to the axis 42 of the planetary gear stage 40. Consequently, torque can be reliably transferred from the motor 20 to the planetary gear stage 40.
It will be appreciated that the use of a single component frame 100 helps provide a stiff mounting structure for both the planetary gear stage 40 and the motor 20. This high stiffness is maintained at higher temperatures that can occur during operation of the actuator 10.
The subassembly of the drive assembly 14 and the frame 100 is then secured to the first portion 152 of the housing 150 as shown in
At the same time, the openings 122 are aligned with the openings 172 and the connecting members 134 are aligned with the recesses 182. Fasteners 204 extend through the aligned openings 122, 172 to directly secure 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 secure the second interface 126 to the first portion 152 of the housing 150. The projections 184 extend into the locating members 136.
Turning to
The control assembly 90 is then joined to the one-piece second portion 190 (
In another example shown in
Once this is accomplished, the drive assembly 14 is inserted through the first portion 152 of the cover 150 and secured directly to the frame 100 in the manner previously discussed. The bulkhead 197 (not shown here) is then inserted into and secured to the rim 194 along the interface IF as previously discussed. Finally, the control assembly 90 is inserted into and secured to the rim 194 along the interface IF2 as previously discussed to enclose the drive assembly 14 and bulkhead 197 within the housing 150.
The actuator assembly 10 can be configured to be secured directly to the remainder of the brake caliper. In one example shown in
The present invention is advantageous because it allows the carrier assembly to redistribute reaction forces generated by the drive assembly in a manner that helps prolong the effective live of the carrier assembly. To this end, the motor is mounted directly to the frame and, thus, the frame provides a robust path for transferring vibrational loads during operation of the motor. More specifically, vibrational loads on the motor, e.g., caused by vibrations in the suspension induced by the road terrain, are transferred through the projections on the frame to the housing. Additionally, the direction connection between the frame and the motor helps to maintain the motor torque applied during application of the parking brake.
What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further 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.
