HOUSING AND FRAME FOR AN EMB ACTUATOR

Abstract

A frame for a vehicle brake actuator assembly is provided, including a housing enclosing a gear stage and a motor for supplying 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. Protrusions extend outwardly from the first interface to receive fasteners for directly securing the base to the housing and transferring loads from the motor to the housing during braking operations.

Description

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

[0002] Carrier assemblies for brake actuators are generally secured to and enclose the working parts of the actuator, such as the motor and planetary gear stage, for use in service and parking braking. Consequently, the carrier assembly assists in absorbing forces generated during braking, such as vibration forces, torque, and reaction forces from holding the parking brake. It is therefore desirable to provide a carrier assembly designed to optimally withstand and / or distribute these forces generated during operation.

[0003] In one example, a frame for a vehicle brake actuator assembly is provided, including a housing enclosing a gear stage and a motor for supplying 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. Projections extend outwardly from the first interface to receive fasteners for directly securing the base to the caliper housing and transferring loads from the frame, and thus from the gear stage and motor, to the caliper housing during braking.

[0004] In another example, a housing for a vehicle brake actuator assembly having a gear stage and a motor for supplying torque to the gear stage comprises a first portion for receiving the gear stage and the motor. A second portion is secured to the first portion for enclosing the gear stage and the motor. The second portion is integrally formed with a control arrangement for controlling the operation of the motor.

[0005] In another example, a method is provided for forming a housing for a vehicle brake actuator assembly having a gear stage and a motor for supplying torque to the gear stage. The method comprises the steps of: providing a first part that houses 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 so that the gear stage and the motor are enclosed within the housing.

[0006] Further objects and advantages and a more complete understanding of the invention will become apparent from the following detailed description and the accompanying drawings. Fig. 1 is a schematic illustration of an exemplary exploded electromechanical brake actuator according to the present invention. Fig. 2 is a perspective view of a drive assembly of the actuator of Fig. 1. Fig. 3A is a top view of a frame of the actuator. Fig. Figure 3B is a perspective view of a frame for the actuator. Fig. 4 is a perspective view of a first portion of a cover for the actuator. Fig. 5 is a top view of a second portion of the cover. Fig. 6 is a view of the second section from below. Fig. Figure 7 is a schematic representation of the drive assembly secured directly to the frame. Fig. Figure 8 is a schematic representation of the first portion of the cover secured to the frame. Fig. Figure 9A is a schematic representation of the second portion of the cover connected to the first portion. Fig. Figure 9B is a schematic diagram of a control assembly connected to the cover. Fig. 10 is another exemplary actuator in which only the frame is secured to the first portion of the housing. Fig. 11 is a schematic representation of the second portion of the housing secured to the first portion. Fig. 12A is a schematic diagram of another exemplary housing. Fig. 12B is a side view of the housing of Fig. 12A. Fig. 12C is a view of a portion of the housing of Fig. 12A from below.

[0007] The present invention relates to electromechanical brake actuators and, more particularly, to a housing and frame for a drive assembly of the actuator. Fig. 1-9 illustrate an electromechanical brake actuator (EMB actuator) assembly 10 for a vehicle according to one aspect of the invention. Referring to Fig. 1-2, the actuator 10 includes a drive assembly 14 and a control assembly 90 for controlling the drive assembly. The drive assembly 14 provides braking force to the vehicle by converting rotation of a motor 20 into longitudinal movement of a piston 74 in a known manner.

[0008] To this end, the motor 20 includes 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 assists in transferring torque from the output gear 24 to the planetary gear stage 40. The planetary gear stage 44 is of conventional construction, centered about an axis 42 and including a sun gear, planetary gears, and an associated carrier, which either rotate about or orbit the axis 42 in a known manner.

[0009] The planetary gear stage 40 is coupled to a spindle drive 70, which includes a spindle 72 rotatable by the planetary gear stage, and a piston 74 axially movable in response to rotation of the spindle. The piston 74 may be connected to the spindle 72, for example, by a ball ramp arrangement, ball races, orbiting 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. By advancing the piston 74 away from the planetary gear stage 40, a braking force is applied to the vehicle, while retracting the piston toward the planetary gear stage reduces or removes the braking force.

[0010] 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 annular 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, the four arms 54 together have a cruciform 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 positioning and rotatably mounting the gear 44.

[0011] With further reference to Fig. 1, the control assembly 90 comprises conventional components for controlling and monitoring the operation of the drive assembly 14, including the operation of the motor 20. This may, for example, comprise a circuit board on which electrical and electronic components are arranged and electrically connected to one another via conductive tracks. The electrical and electronic components form a speed regulation unit for regulating the speed of the motor 20. A current measuring unit measures a current received from the motor 20. A current supply unit supplies electrical energy to the motor 20. A temperature measuring unit measures the temperature in the actuator 10. A force measuring unit measures a brake actuation force supplied by the actuator 10. A rotational position detection unit monitors a rotational position of the motor 20.

[0012] With reference to Fig. 3A-3B, a support member or frame 100 is provided for supporting the planetary gear stage 40 and the motor 20. The frame 100 is formed as a single unitary piece of metal, such as aluminum. The frame 100 includes a base 102 defining first and second interfaces 106, 126. The first interface 106 may be formed as a ring centered about an axis 110. Protrusions or tabs 112 extend outwardly from opposite sides of the ring 106. As shown, a pair of diametrically opposed tabs 112 extend outwardly from the ring 106. More or fewer tabs 112 are contemplated as alternative configurations for the tabs.

[0013] A positioning member 114 is 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 disposed around the ring 106. In one example, four connecting members 120 are evenly spaced around the ring 106. The connecting members 120 may be formed as threaded spacers.

[0014] 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 around the second interface 126. Connecting members 134 are provided circumferentially around the ring 126. The connecting members 134 may be formed as projections with a passage extending therethrough. A cylindrical positioning member 136 is provided adjacent each interface 106, 126. A bearing or receptacle 140 is provided on the base 102 between and aligned with the axes 110, 130.

[0015] A housing 150 encloses the drive assembly 14 and the frame 100 and includes a first portion or base part 152 ( Fig. 4) and a second section or cover part 190 ( Fig. 5-6). With specific reference to Fig. 4, the first portion 152 includes a ring member 154 defining an opening 156. A recess 160 surrounds the opening 156. Pockets 166 extend radially outward from the ring member 154. As shown, the pockets 166 are diametrically opposed to each other. An opening 170 extends through each pocket 166. Openings 172 are provided around the periphery of the opening 156 and adjacent the pockets 166.

[0016] An engine cover 180 extends in a direction generally parallel to the depth of the opening 156. The engine cover 180 may be formed as a cylinder closed at one end. A series of pockets or recesses 182 are circumferentially disposed around the end of the engine cover 180. The recesses 182 may be diametrically opposed to one another.

[0017] The second section 190 ( Fig. 5-6) includes a wall 192 having an open polygonal shape. A peripheral rim 194 extends along the entire periphery of the wall 192. Protrusions 196 extend outwardly from opposite sides of the wall 192. As shown, the protrusions 196 extend in opposite directions and lie in the same plane. An opening 200 extends through each protrusion 196.

[0018] A partition 197 is formed integrally with the wall 192 and the rim 194 and is generally positioned at the interface therebetween. The partition 197 is recessed from the upper surface of the rim 194 and extends across the entire base of the wall 192. In other words, the partition 197 closes the interior of the wall 192. By integrally forming the wall 192, the rim 194, and the partition 197 as a single composite piece, e.g., by injection molding, the need to secure separate components together with fasteners such as screws or adhesives or by welding is eliminated. This advantageously eliminates the need for a separate seal along the partition / wall / rim interface(s), thereby reducing assembly complexity and parts count.At the same time, by integrally forming the wall 192 and the partition 197 as a single piece with no interface / joint, the need to provide potting material between the periphery of the partition and the interior of the wall to assist in bonding the components together is eliminated.

[0019] In an example shown in Fig. As shown in Figure 7, to assemble the actuator 10, the planetary gear stage 40 is connected to the first interface 106, and the motor 20 is connected to the second interface 126. To this end, fasteners 202 extend through the openings 56 in the arms 54 of the support member 50 and into the connecting members 120 to secure the support member, and thus the planetary gear stage 40 and the spindle assembly 70 connected thereto, to the frame 100.

[0020] This securely fixes the planetary gear stage 40 in the first interface 106 and aligns the axes 42, 110. At the same time, the 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 bearing 140, so that the gear 44 meshes with both the gear 24 and the planetary gear stage 40.

[0021] It is understood that a portion of the motor 40 is received in the centering surface 128 such that the rotational axis 26 of the motor 20 is aligned with the axis 130 of the second mounting 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.

[0022] It will be appreciated that the use of a single component frame 100 helps provide a rigid mounting structure for both the planetary gear stage 40 and the motor 20. This high rigidity is maintained at higher temperatures that may occur during operation of the actuator 10.

[0023] 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 Fig. 8. Specifically, the frame 100 is aligned with the first portion 152 such that the motor 20 extends into the motor cover 180 and the first interface 106 is positioned in the recess 160. This positions the positioning members 114 in the openings 170 of the housing 150. First seals 210 are provided between the pockets 166 in the first portion 152 and the projections 112. In one example, the first seals 210 are standard O-ring seals or (dual-component) seals integrated into the pockets 166.

[0024] 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 positioning members 136.

[0025] With reference to Fig. 9A, the one-piece second section 190 is positioned over the frame 100 so that the positioning members 114 on the frame extend through the openings 200 in the projections 196. Second seals 212 are provided over the positioning members 114 on the frame 100, between the positioning members and the projections 196 on the wall 192. The wall 192 extends around and surrounds the remainder of the frame 100 and forms an interface between the periphery of the wall and the periphery of the first section 152. The interface between the first and second sections 152, 190 of the housing 150 (indicated as "IF1") is then fused, for example, by welding.

[0026] The control assembly 90 is then connected to the one-piece second section 190 without any necessary fastening means, such as screws or adhesives ( Fig. 9B). Instead, the control assembly 90 is fused to the rim 194, e.g., by laser welding, vibration welding, or ultrasonic welding, in an integrated process in which it also covers the partition wall 197. To this end, the peripheries of the control assembly 90 and the upper surface of the rim 194 are aligned along an interface (indicated as "IF2") and welded together. This advantageously eliminates the need to provide a separate seal along the interface between the control assembly and the rim, thereby reducing assembly complexity and parts count.

[0027] By attaching the frame to a caliper housing via the bosses 112, positioning members 114, and fasteners, the frame 100 can transfer vibration and other forces / stresses from the engine 20 and transmission stage 40, through the bosses 112, and ultimately to the caliper housing 250, while avoiding or mitigating the transfer of any vibration loads from the frame to the housing 150 and thus to the control assembly 90.

[0028] In another example, which is Fig. 10, the frame 100 is secured to the first portion 152 of the housing 150 as previously described, but without first attaching the drive device 14 to the frame. In this example, the control assembly 90 and the second portion 190 are not preassembled into a single unit. Instead, and further with reference to Fig. 11, the wall 192 is positioned alone over the frame 100 so that the positioning members 114 on the frame extend through the openings 200. The second seals 212 are provided over the positioning members 114 on the frame 100, between the positioning members and the projections 196 on the wall 192. The wall 192 extends around and surrounds the remainder of the frame 100 and forms an interface between the periphery of the wall and the periphery of the first section 152. The first and second sections 152, 192 are then securely fixed directly to one another along the interface, for example, by laser welding, epoxy, etc.

[0029] 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 partition 197 (not shown here) is then inserted into the edge 194 and secured thereto along the interface IF as previously discussed. Finally, the control assembly 90 is inserted into the edge 194 and secured thereto along the interface IF2 as previously discussed to enclose the drive assembly 14 and the partition 197 within the housing 150.

[0030] The actuator assembly 10 may be configured to be secured directly to the rest of the brake caliper. In an example shown in Fig.12A-12C, the projections 196 on the wall 192 are elongated to thereby lengthen the openings 200. This means that the openings 200 allow the frame 100—more specifically, the projections 112—to extend through the entire depth of the projections 196 for direct connection to the caliper 250. This allows the frame 100 to transmit vibration and other forces / stresses from the engine 20 and transmission 40, through the projections 112, and ultimately to the caliper housing 250, while avoiding or mitigating the transmission of any vibration loads from the frame to the wall 192. Furthermore, this advantageously allows the first and second portions 152, 190 of the housing to be integrally formed as a single piece without the need for fasteners or the like.

[0031] The present invention is advantageous in that it allows the support assembly to redistribute reaction forces generated by the drive assembly in a manner that helps extend the effective life of the support assembly. To this end, the engine is mounted directly to the frame, and thus the frame provides a robust path for the transmission of vibration loads during engine operation. More specifically, vibration loads on the engine, caused, for example, by vibrations in the wheel suspension induced by road terrain, are transmitted to the housing through the projections on the frame. Furthermore, the direction of the connection between the frame and the engine helps maintain the engine torque applied during parking brake application.

[0032] Examples of the present invention have been described above. It is, of course, not possible to describe every conceivable combination of components or methods for the purpose of describing the present invention; however, it will be apparent to one of ordinary skill in the art that many other combinations and substitutions are possible in the present invention. Accordingly, the present invention is intended to embrace all such changes, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

[1] A frame (100) for an actuator assembly (10) of a vehicle brake, comprising a housing (150) enclosing the frame (100), a gear stage (40), and a motor (20) for supplying torque to the gear stage (40), comprising: a base (102) having a first interface (106) for connection to the gear stage (40) and a second interface (126) for connection to the motor (20), wherein projections (112) for receiving fasteners for directly securing the base (102) to a housing of the vehicle brake extend outwardly from the first interface (106) and transfer loads from the motor (20) to the housing of the vehicle brake during braking operations. [2] Frame (100) according to claim 1, wherein the projections (112) are formed integrally with the base (102). [3] Frame (100) according to one of the preceding claims, wherein the projections (102) extend away from each other. [4] Frame (100) according to one of the preceding claims, wherein the projections (102) are diametrically opposed to each other about an axis (110) centered on the first interface (106). [5] Frame (100) according to one of the preceding claims, wherein the base (102) is formed of metal. [6] Housing (150) for an actuator arrangement (10) of a vehicle brake with a frame (100) for receiving a gear stage (40) and a motor (20) for supplying torque to the gear stage (40), comprising: a first section (152) for receiving the frame (100), the gear stage (40) and the motor (20); and a separate second portion (190) secured to the first portion (152) for enclosing the frame (100), the gear stage, and the motor. [7] The housing (150) of claim 6, wherein the first portion (152) and the second portion (190) comprise a cooperating structure for receiving outwardly extending projections (112) on the frame (100). [8] Housing (150) according to claim 6 or claim 7, wherein the first portion (152) and the second portion (190) are fused and / or welded and / or glued along an interface (IF1) to seal the interface. [9] A housing (150) according to any one of the preceding claims, wherein the second portion (190) comprises an open wall (192) and a partition wall (197) formed integrally with the wall (192) and closing the interior thereof for enclosing the frame (100), the gear stage and the motor. [10] The housing (150) of claim 9, wherein the interface between the second portion (190) and the partition wall (197) does not comprise any potting material. [11] Housing (150) according to one of the preceding claims, wherein the second portion (190) is fused along an interface (IF2) with a control arrangement (90) for controlling the operation of the motor (20). [12] The housing (150) of claim 11, wherein the second portion (190) and the control assembly (90) are welded along an interface (IF2) to seal the interface. [13] The housing (150) of any one of claims 6 to 12, wherein the second portion (190) includes a wall (192) and projections (196) extending outwardly from the wall (192) for securing to the frame (100) of the actuator assembly (10) supporting the gear stage (40) and the motor (10). [14] A method for forming a housing (150) for an actuator assembly (10) of a vehicle brake having a frame (100), a gear stage (40) and a motor (20) for supplying torque to the gear stage, comprising: - providing a first section (152) which receives the frame (100), the gear stage (40) and the motor (20); - providing a second portion (190) having an open wall (192) and a partition wall (197) formed integrally with the wall (192) and closing the interior thereof; and - fusing an interface (IF1) between the first section (152) and the second section (190) so that the frame (100), the gear stage (40) and the motor (20) are enclosed in the housing (150). [15] Method according to claim 14, further comprising fusing, in particular fusing by means of laser welding, ultrasonic welding or vibration welding, an interface (IF2) between the second section (190) and a control arrangement (90) for controlling the operation of the motor (20); and / or further comprising fusing the interface (IF1) welding the interface (IF1) between the first and second sections (152, 190).

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