US 12,403,879 B2
Power transmission unit and brake systems using same
Blaise J. Ganzel, Ann Arbor, MI (US)
Assigned to ZF ACTIVE SAFETY US INC., Livonia, MI (US)
Filed by ZF Active Safety US Inc., Livonia, MI (US)
Filed on Aug. 12, 2021, as Appl. No. 17/400,326.
Prior Publication US 2023/0048069 A1, Feb. 16, 2023
Int. Cl. B60T 8/40 (2006.01); B60T 7/08 (2006.01); B60T 13/14 (2006.01); B60T 13/68 (2006.01); B60T 13/74 (2006.01); B60T 15/02 (2006.01); B60T 17/22 (2006.01)
CPC B60T 13/745 (2013.01) [B60T 7/085 (2013.01); B60T 13/148 (2013.01); B60T 13/686 (2013.01); B60T 15/028 (2013.01); B60T 17/221 (2013.01); B60T 2220/04 (2013.01); B60T 2270/402 (2013.01); B60T 2270/403 (2013.01); B60T 2270/404 (2013.01); B60T 2270/82 (2013.01); B60T 2270/88 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A power transmission unit of a single-acting plunger type, the power transmission unit comprising:
a ball screw;
a ball nut selectively driven by the ball screw for longitudinal motion relative thereto;
a plunger piston operatively coupled to the ball nut;
a block housing at least partially enclosing the plunger piston and the ball screw;
a plunger chamber at least partially defined by the block housing and a face of the plunger piston, the plunger chamber being configured to contain hydraulic fluid and selectively pressurized by reciprocal motion of the plunger piston with respect to the block housing driven by longitudinal motion of the ball nut;
an output channel selectively placing the plunger chamber in fluid communication with at least one component of a brake system including the power transmission unit;
an electric motor for selectively driving the ball screw to responsively reciprocate the plunger piston within the plunger chamber;
a motor housing at least partially enclosing the ball nut, the electric motor, and the plunger piston, the motor housing including a block lip which is crimped to the block housing to maintain the motor housing in relation to the block housing; and
a bearing for rotatably supporting a supported end of the ball screw spaced apart from the plunger chamber, wherein the motor housing includes a bearing recess with a bearing lip crimped onto at least a portion of the bearing to maintain the bearing in relation to the motor housing.