Actuator of variable compression ratio mechanism and actuator of link mechanism

Patent metadata

Field	Value
Publication number	US-9797307-B2
Application number	US-201514613035-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Feb 4, 2014
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

An actuator of a variable compression ratio mechanism includes: a control link; an arm link; a control shaft; a housing including a receiving portion in which a connection portion between the second end portion of the control link and the arm link is received, and a support hole formed within the housing, and rotatably supporting the control shaft; and a speed reduction device, the control shaft including a fixing portion inserted and fixed within the receiving portion in a fixing hole formed in the arm link at a predetermined axial position, and a first journal portion which is formed at a tip end portion of the control shaft, which has a diameter smaller than a diameter of the fixing portion, and which is supported by a first bearing hole formed in the support hole.

First claim

What is claimed is:

1. An actuator of a variable compression ratio mechanism arranged to vary at least one of an upper dead center position and a lower dead center position of a piston of an internal combustion engine, and to vary a mechanical compression ratio, the actuator comprising:
a control link including a first end portion linked with the piston, and a second end portion, and arranged to vary a position characteristic of the piston;
an arm link rotatably connected to the second end portion of the control link;
a control shaft which is a member different from the arm link, and to which the arm link is fixed;
a housing including a receiving portion in which a connection portion between the second end portion of the control link and the arm link is received, and a support hole defined by walls of the housing, and rotatably supporting the control shaft; and
a speed reduction device arranged to reduce a rotation speed of the motor, and to transmit the reduced rotation to the control shaft,
the control shaft including a fixing portion inserted and fixed within the receiving portion in a fixing hole formed in the arm link at a predetermined axial position, and a first journal portion which is formed at a tip end portion of the control shaft, which has a diameter smaller than a diameter of the fixing portion, and which is supported by a first bearing hole formed in the support hole defined by the walls of the housing,
wherein the control shaft includes a second journal portion which is located at a position opposite to the tip end portion to sandwich the fixing portion, which has a diameter larger than an outside diameter of the fixing portion, and which is supported by a second bearing hole of the support hole defined by the walls of the housing.

2. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the arm link includes the fixing hole which is fixed to the fixing portion of the control shaft, a protrusion portion formed on the outer circumference portion of the control shaft, and a connection hole which is formed in the protrusion portion, and which is connected to the control link.

3. The actuator for the variable compression ratio mechanism as claimed in claim 2 , wherein the fixing portion of the control shaft is fixed in the fixing hole of the arm link by a press-fit.

4. The actuator for the variable compression ratio mechanism as claimed in claim 3 , wherein
the control shaft includes a stepped portion formed between the second journal portion and the fixing portion; and
the arm link includes a first end portion arranged to be restricted to be moved in the axial direction by the stepped portion.

5. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein
the control shaft is made from iron series metal; and
an entirety of the housing including the first bearing hole and the second bearing hole is made from aluminum alloy.

6. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the first end portion of the control link is rotatably connected through a connection pin inserted into a connection hole formed in a second end portion of the arm link.

7. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the speed reduction device includes an inner gear which has an exact circle shape, which is integrally connected with the control shaft, and which includes an inner circumference having internal teeth, an external gear which is disposed on an inner circumference side of the internal gear, and which includes an outer circumference including external teeth engaged with the internal teeth, which flexibly varies its shape, and whose number of the teeth is smaller than a number of the teeth of the internal teeth, and a wave generation device including an outer circumference surface which is disposed and abutted on the inner circumference surface of the external gear, and arranged to abut the external gear on the internal gear by the rotation of the motor.

8. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the receiving portion of the housing includes an opening portion opened to the outside.

9. The actuator for the variable compression ratio mechanism as claimed in claim 8 , wherein the support hole is formed in a direction crossing the receiving portion.

10. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the control shaft is inserted into the support hole after the arm link is received within the receiving portion, such that the first journal portion is disposed within the first bearing hole.

11. The actuator for the variable compression ratio mechanism as claimed in claim 10 , wherein the fixing portion of the control shaft is fixed in the fixing hole of the arm link when the control shaft is inserted in the support hole.

12. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein
the control shaft include a stepped surface formed between the fixing portion and the first journal portion on a tip end side; and
the stepped surface of the control shaft is abutted on a hole edge portion formed between the receiving portion of the housing and the first bearing hole, so as to restrict an axial position of the control shaft.

13. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the actuator further comprises an angle sensor disposed on the first bearing hole's side of the support hole, and arranged to sense a rotation angle of the control shaft.

14. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the housing comprises an insertion hole structured to receive the control shaft, and the insertion hole does not accommodate the arm link.

15. The actuator for the variable compression ratio mechanism as claimed in claim 1 , wherein the support hole extends within the housing from a bottom surface of a groove portion of the housing.

16. An actuator used for driving a link mechanism, the actuator comprising:
a control link including a first end portion connected to the link mechanism, and a second end portion;
an arm link rotatably connected to the second end portion of the control link;
a control shaft which is a member different from the arm link, and to which the arm link is fixed;
a housing which includes a receiving portion receiving a connection portion of the second end portion of the control link and the arm link, and which rotatably supports the control shaft passing through the receiving portion; and
a speed reduction device arranged to reduce a rotation speed of a drive motor, and to transmit the reduced rotation to the control shaft,
the arm link including a fixing hole in which the control shaft is inserted and fixed within the receiving portion, and
the control shaft including a fixing portion inserted and fixed within the receiving portion in a fixing hole formed in the arm link at a predetermined axial position, and a first journal portion which is formed at a tip end portion of the control shaft, which has a diameter smaller than a diameter of the fixing portion, and which is supported by a first bearing hole defined by the housing,
wherein the control shaft includes a second journal portion which is positioned at a position opposite to the tip end portion to sandwich the fixing portion, which has a diameter larger than an outside diameter of the fixing portion, and which is supported by a second bearing hole defined by the housing.

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Onigata Junichiro
• Yamada Yoshihiko
• Nagai Kishiro

Classifications

• Y10T74/2151

  Longitudinally adjustable · CPC title

• F02B75/045 Primary

  by means of a variable connecting rod length · CPC title

• F02D15/02

  by alteration or displacement of piston stroke · CPC title