Electric parking brake driving device and electric parking brake device

Patent metadata

Field	Value
Publication number	US-9297433-B2
Application number	US-201214113504-A
Country	US
Kind code	B2
Filing date	Apr 23, 2012
Priority date	Apr 26, 2011
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A parking brake actuator generates and applies a braking force to a vehicle wheel by converting a rotation movement of a screw member which is rotated by an electric parking brake driving device into a translatory movement and transmitting the converted translatory movement to a piston to push a brake pad to a disc by the piston. The electric parking brake driving device includes an electric motor and a reduction gear mechanism which transmits the driving force of the electric motor to the electric parking brake driving device. The reduction gear mechanism includes a pinion gear fixed to an output shaft of the electric motor, a first gear shaft rotatably supported on a first bearing member provided on a gear body and a first wheel gear formed on the first gear shaft and engaging the first wheel gear to thereby reduce the speed of driving force of the electric motor.

First claim

The invention claimed is:

1. An electric parking brake driving device for driving a parking brake actuator which generates a braking force and applies the braking force to a vehicle wheel by converting a rotational movement from a rotating member into a translatory movement, transmitting the converted translatory movement to a piston and by pushing a disc rotated together with the vehicle wheel by a brake pad biased by the piston, the electric parking brake driving device comprising:
an electric motor; and
a reduction gear mechanism for transmitting a driving force of the electric motor to the rotating member, wherein the reduction gear mechanism includes:
a gear body;
a drive gear provided in the gear body and fixed to an output shaft of the electric motor;
a first rotating shaft rotatably supported on the gear body through a first bearing portion provided on the gear body;
a first driven gear formed on the first rotating shaft and having a plurality of gear teeth more than a number of gear teeth formed on the drive gear, whereby the first driven gear engages with the drive gear;
a transmitting gear formed on the first rotating shaft and integrally rotating with the first driven gear;
a second rotating shaft rotatably supported on the gear body through a second bearing portion provided on the gear body, the second rotating shaft being rotatable about an axis which extends in an axial direction;
a second driven gear formed on the second rotating shaft and having a plurality of gear teeth more than a number of gear teeth formed on the transmitting gear, whereby the second driven gear engages with the transmitting gear;
a sun gear provided on the second rotating shaft and integrally rotating with the second driven gear;
a plurality of planetary gears engaged with the sun gear and orbiting around an outer periphery of the sun gear in response to the rotation of the sun gear;
a ring gear disposed around the planetary gears and engaging therewith at an inner peripheral surface, the ring gear being non-rotatable by engaging with the gear body; and
a carrier member connecting the plurality of planetary gears and at the same time connected to the rotating member to be rotated by the orbiting of the planetary gears, whereby a rotation of the sun gear is outputted to the rotating member through a reduction, wherein
the second bearing portion includes a pair of second bearing members,
the gear body includes a supporting wall which is formed integrally with an outer wall of the gear body and extends from the outer wall towards a rotation center of the second rotating shaft to separate the planetary gears from the second driven gear, the supporting wall being disposed between the second driven gear and the planetary gears relative to the axial direction,
one of the pair of second bearing members is disposed on the supporting wall to support the second rotating shaft at one side of the second driven gear, and
an other of the pair of second bearing members is disposed on the gear body to support the second rotating shaft at an other side of the second driven gear opposite to the one side of the second driven gear relative to the axial direction.

2. The electric parking brake driving device according to claim 1 , wherein
the gear body is formed by a pair of body pieces which is connected with each other so that a space with a predetermined volume is provided inside the gear body, and wherein
the pair of body pieces is connected at each outer peripheral brim thereof by an adhesive agent.

3. The electric parking brake driving device according to claim 1 , wherein
the gear body is formed by a pair of body pieces which is connected with each other so that a space with a predetermined volume is provided inside the gear body,
both of the pair of body pieces are formed by a thermoplastic synthetic resin material, and wherein
the two body pieces are connected by contacting respective outer peripheral brim portions with each other, placing a linear shaped heating element between the respective outer peripheral brim portions and under developing heat by energizing the heating element, connecting the both body pieces by applying pressure to each other by welding.

4. An electric parking brake device comprising:
a brake housing attached to a vehicle body;
a piston attached to and displaceable relative to the brake housing;
a brake pad disposed between a disc which rotates with a vehicle wheel and the piston;
an electric motor provided to be non-displaceable relative to the brake housing;
a reduction gear mechanism for transmitting a driving force of the electric motor;
a rotating member driven by the electric motor within the brake housing through the reduction gear mechanism; and
a translatory member engaging with the rotating member and being non-rotatable relative to the brake housing but displaceable in an axial a direction of the piston by the rotation of the rotating member for biasing the brake pad towards the disc through the piston, wherein the reduction gear mechanism includes:
a gear body attached to the brake housing;
a drive gear provided in the gear body and fixed to an output shaft of the electric motor;
a first rotating shaft rotatably supported on the gear body through a first bearing portion provided on the gear body;
a first driven gear formed on the first rotating shaft and having a plurality of gear teeth more than a number of gear teeth formed on the drive gear, whereby the first driven gear engages with the drive gear;
a transmitting gear formed on the first rotating shaft and integrally rotating with the first driven gear;
a second rotating shaft rotatably supported on the gear body through a second bearing portion provided on the gear body, the second rotating shaft being rotatable about an axis which extends in an axial direction;
a second driven gear formed on the second rotating shaft and having a plurality of gear teeth more than a number of gear teeth formed on the transmitting gear, whereby the second driven gear engages with the transmitting gear;
a sun gear provided on the second rotating shaft and integrally rotating with the second driven gear;
a plurality of planetary gears engaging with the sun gear and orbiting an outer periphery of the sun gear in response to the rotation of the sun gear;
a ring gear disposed around the planetary gears and engaging with the planetary gears at an inner peripheral surface, whereby the rotation of the ring gear is restricted by engaging with the gear body; and
a carrier member connecting the plurality of planetary gears and connected to the rotating member to be rotated by an orbiting of the planetary gears, whereby a rotation of the sun gear is outputted to the rotating member through a reduction, wherein
the second bearing portion includes a pair of second bearing members,
the gear body includes a supporting wall which is formed integrally with an outer wall of the gear body and extends from the outer wall towards a rotation center of the second rotating shaft to separate the planetary gears from the second driven gear, the supporting wall being disposed between the second driven gear and the planetary gears relative to the axial direction,
one of the pair of second bearing members is disposed on the supporting wall to support the second rotating shaft at one side of the second driven gear, and
an other of the pair of second bearing members is disposed on the gear body to support the second rotating shaft at an other side of the second driven gear opposite to the one side of the second driven gear relative to the axial direction.

Assignees

• Takewaki Morimasa
• Takeo Yuichi
• Sakai Kosuke
• Ozawa Masakazu
• Takasu Katsuhiko
• Advics Co Ltd

Inventors

• Takewaki Morimasa
• Takeo Yuichi
• Sakai Kosuke
• Ozawa Masakazu
• Takasu Katsuhiko

Classifications

• F16D65/18 Primary

  adapted for drawing members together {, e.g. for disc brakes} · CPC title

• F16D55/225

  the braking members being brake pads · CPC title

• F16H2025/2081

  Parallel arrangement of drive motor to screw axis · CPC title

• F16H2025/2087

  using planetary gears · CPC title

• F16D2125/50

  with parallel non-stationary axes, e.g. planetary gearing · CPC title