Crankshaft

Patent metadata

Field	Value
Publication number	US-10066699-B2
Application number	US-201514963961-A
Country	US
Kind code	B2
Filing date	Dec 9, 2015
Priority date	Dec 12, 2014
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A flat plane crankshaft for an in-line four cylinder engine includes eight crank arms. A fourth crank arm and a fifth crank arm are respectively provided with counter weights. Each of a width of the fourth crank arm and a width of the fifth crank arm is configured to be smaller than a width of a second crank arm. Each of a width of the third crank arm and a width of the sixth crank arm is configured to be greater than the width of the second crank arm.

First claim

What is claimed is:

1. A flat plane crankshaft for an in-line four cylinder engine, the crankshaft comprising:
five crank journals;
four crank pins; and
eight crank arms including:
a first crank arm being a crank arm of the eight crank arms at a first position counted from one of both shaft ends of the crankshaft;
a second crank arm being a crank arm of the eight crank arms at a second position counted from the shaft end of the crankshaft;
a third crank arm being a crank arm of the eight crank arms at a third position counted from the shaft end of the crankshaft;
a fourth crank arm being a crank arm of the eight crank arms at a fourth position counted from the shaft end of the crankshaft, the fourth crank arm including a fourth counter weight of the fourth crank arm;
a fifth crank arm being a crank arm of the eight crank arms at a fifth position counted from the shaft end of the crankshaft, the fifth crank arm including a fifth counter weight of the fifth crank arm;
a sixth crank arm being a crank arm of the eight crank arms at a sixth position counted from the shaft end of the crankshaft;
a seventh crank arm being a crank arm of the eight crank arms at a seventh position counted from the shaft end of the crankshaft; and
an eighth crank arm being a crank arm of the eight crank arms at an eighth position counted from the shaft end of the crankshaft,

each of the fourth crank arm and the fifth crank arm having a smaller width than a width of the second crank arm,
each of the third crank arm and the sixth crank arm having a greater width than the width of the second crank arm,
when viewed from the shaft end of the crankshaft, a width of the first crank arm, the second crank arm, the seventh crank arm, and the eighth crank arm are each defined as a maximum value of a dimension of each respective crank arm between a journal central axis, and one of a central axis of a first crank pin of the four crank pins and a central axis of a fourth crank pin of the four crank pins in a direction orthogonal to a line segment vertically extending through the journal central axis, and
when viewed from the shaft end of the crankshaft, a width of the third crank arm, the fourth crank arm, the fifth crank arm, and the sixth crank arm are each defined as a maximum value of a dimension of each respective crank arm between the journal central axis, and one of a central axis of a second crank pin of the four crank pins and a central axis of a third crank pin of the four crank pins.

2. The crankshaft according to claim 1 , wherein the width of the fourth crank arm and the width of the fifth crank arm are greater than a diameter of a crank journal of the five crank journals that is disposed between the fourth crank arm and the fifth crank arm.

3. The crankshaft according to claim 1 , wherein both a ratio of the width of the third crank arm relative to the width of the fourth crank arm and a ratio of the width of the sixth crank arm relative to the width of the fifth crank arm are configured to be an identical ratio within a range of 1.03 to 1.26.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ono Koichi

Classifications

• F16C3/08

  made in one piece (features relating to lubrication F16C3/14, to cooling F16C3/16) · CPC title

• F02B75/20

  with cylinders all in one line · CPC title

• F16F15/283 Primary

  for engine crankshafts · CPC title

• F16C2360/22

  Internal combustion engines · CPC title

• F16C3/20

  Shape of crankshafts or eccentric-shafts having regard to balancing · CPC title