Valve apparatus

Patent metadata

Field	Value
Publication number	US-9500162-B2
Application number	US-201313948689-A
Country	US
Kind code	B2
Filing date	Jul 23, 2013
Priority date	Aug 2, 2012
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A valve apparatus performs at least one of a first operation in which an electric motor is energized in a valve-close direction and a rotation shaft is rotated until its rotation is stopped and a second operation in which the electric motor is deenergized and a valve is fully closed by a biasing force of a return spring. Thereby, a rotation angle of the rotation shaft becomes a rotation-stop angle or the rotation angle becomes in the backlash range, so that a biasing force of the return spring is not transmitted to the rotation shaft. Then, the electric motor generates a specified torque, which is less than a valve-opening torque by which the valve starts opening. Thereby, a rotation angle of the rotation shaft can be stopped at a full-close angle. The full-close angle can be made correspond to an output of a rotational angle sensor.

First claim

What is claimed is:

1. A valve apparatus comprising:
a slide shaft which slides in its axial direction to open and close a valve;
a return spring biasing the slide shaft in a valve-close direction;
an electric actuator having an electric motor which rotates a rotation shaft;
a rotation-linear conversion portion converting a rotational movement of the rotation shaft into a linear movement of the slide shaft in its axial direction;
an electronic control unit having a computer;
a rotational angle sensor detecting a rotation angle of the rotation shaft; and
a learning portion making a correspondence between a full-close angle of the rotation shaft at a full closed position of the valve and an output signal of the rotational angle sensor, wherein:
the electric motor is a direct-current motor which generates a rotation torque according to an energization amount,
the electronic control unit, upon execution of the learning portion by the computer of the electronic control unit, controls the electric motor to perform at least one of a first operation in which the electric motor is energized in a valve-close direction and the rotation shaft is rotated until its rotation is stopped, and a second operation in which the electric motor is deenergized and the valve is fully closed by a biasing force of the return spring only, whereby the rotation angle of the rotation shaft is brought into a rotation-stop angle which is advanced in an anti-valve-close direction or a backlash range, and
the electric motor is energized to rotate in the valve-open direction, whereby a specified torque, which is less than a valve-opening torque by which the valve starts opening, is applied from the rotation shaft to the slide shaft, so that the rotation angle of the rotation shaft is compulsorily brought into the rotation-stop angle and the output signal of the rotational angle sensor is made so as to correspond to the full-close angle.

2. A valve apparatus according to claim 1 , wherein:
when the electronic control unit, upon execution of the learning portion by the computer of the electronic control unit, makes the output signal of the rotational angle sensor correspond to the full-close angle, an energization amount to the electric motor is continuously or stepwisely increased to a specified amount.

3. A valve apparatus according to claim 1 , wherein:
the rotation-linear conversion portion is a link mechanism provided with a cam plate rotating with the rotation shaft and a cam follower provided to the slide shaft in such a manner as to engage with a cam groove of the cam plate.

4. A valve apparatus according to claim 1 , wherein:
the electronic actuator has the electric motor and a reduction mechanism increasing a rotation torque of the electric motor to drive the rotation shaft.

5. A valve apparatus according to claim 1 , wherein:
the return spring is a compression spring arranged around the slide shaft in such a manner as to apply its resilient force to the slide shaft through a spring seat.

6. A valve apparatus according to claim 1 , wherein:
the valve apparatus is an EGR valve which opens and closes an EGR passage through which a part of exhaust gas emitted from an engine is returned to an intake passage of the engine.

7. A valve apparatus according to claim 1 , wherein the full-close angle of the rotation shaft is the most close to an angle at which the valve is opened.

8. A valve apparatus according to claim 1 , wherein a specified torque, which is less than a valve-opening torque by which the valve starts opening, is applied to the slide shaft.

9. A valve apparatus according to claim 1 , wherein while the rotation shaft is rotated, a torque is applied to the rotation shaft in such a manner that the slide shaft does not slide.

Assignees

• Denso Corp

Inventors

• Sasaki Kazushi
• Sano Ryo
• Ishigaki Satoshi
• Shimada Hiroki

Classifications

• F16K31/042

  with electric means, e.g. for controlling the motor or a clutch between the valve and the motor · CPC title

• F02M26/54 Primary

  Rotary actuators, e.g. step motors · CPC title

• F16K37/0083

  by measuring valve parameters · CPC title

• F16K31/52408

  comprising a lift valve · CPC title

• F16K31/047

  characterised by mechanical means between the motor and the valve, e.g. lost motion means reducing backlash, clutches, brakes or return means (F16K31/043 takes precedence) · CPC title