Power transmission shaft and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-11512761-B2
Application number	US-201816612496-A
Country	US
Kind code	B2
Filing date	May 18, 2018
Priority date	Jun 30, 2017
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

A propeller shaft (1) that is a power transmission shaft has a shaft member (2) as a tubular body made of iron-based metal and a balance weight (3) made of iron-based metal and welded to an outer peripheral surface of this shaft member (2). At least a part of the balance weight (3) of the propeller shaft (1) is covered with a sacrificial metal coating (4) made of sacrificial corrosion prevention material that contains metal whose ionization tendency is higher than that of metal forming the shaft member (2). With this, it is possible to suppress local progression of corrosion at a periphery of the balance weight (3) and improve durability of the propeller shaft (1).

First claim

The invention claimed is:

1. A power transmission shaft comprising:
a tubular body made of iron-based metal and having, at least at a part of an outer peripheral surface thereof, an uncovered portion that is not covered;
a balance weight formed into a plate shape with the same iron-based metal as the tubular body, wherein an inner side surface thereof, which faces the uncovered portion of the tubular body, is covered with a first cover layer made of sacrificial corrosion prevention material that contains metal whose ionization tendency is higher than that of metal forming the tubular body, and wherein an outer side surface thereof is covered with a second cover layer made of different material from the first cover layer with the first cover layer being exposed; and
a projecting portion formed integrally with the balance weight on the inner side surface, which faces the uncovered portion of the tubular body, of the balance weight, wherein the balance weight is fixed to the tubular body with a top end portion, which is not covered with the sacrificial corrosion prevention material, of the projecting portion being welded to the uncovered portion of the tubular body.

2. The power transmission shaft as claimed in claim 1 , wherein:
the first cover layer is formed on an entire surface of the balance weight.

3. The power transmission shaft as claimed in claim 1 , wherein:
the sacrificial corrosion prevention material is made of zinc, magnesium, aluminum or an alloy containing at least one of these metals.

4. A power transmission shaft comprising:
a tubular body made of iron-based metal; and
a balance weight having;
a rivet made of iron-based metal and fixed to the tubular body, and
a weight body made of iron-based metal and having a penetration hole which the rivet penetrates, wherein at least a part of the weight body is covered with sacrificial corrosion prevention material that contains metal whose ionization tendency is higher than that of metal forming the tubular body,
wherein the balance weight is fixed to an outer peripheral surface of the tubular body with the rivet, and
wherein the weight body is fixed to the outer peripheral surface of the tubular body with the rivet penetrating the penetration hole being riveted.

5. A method of manufacturing a power transmission shaft, the power transmission shaft having;
a tubular body made of iron-based metal and having, at least at a part of an outer peripheral surface thereof, an uncovered portion that is not covered;
a balance weight formed into a plate shape with the same iron-based metal as the tubular body, wherein an inner side surface thereof, which faces the uncovered portion of the tubular body, is covered with a first cover layer made of sacrificial corrosion prevention material that contains metal whose ionization tendency is higher than that of metal forming the tubular body, and wherein an outer side surface thereof is covered with a second cover layer made of different material from the first cover layer with the first cover layer being exposed; and
a projecting portion formed integrally with the balance weight on the inner side surface, which faces the uncovered portion of the tubular body, of the balance weight, wherein the balance weight is fixed to the tubular body with a top end portion, which is not covered with the sacrificial corrosion prevention material, of the projecting portion being welded to the uncovered portion of the tubular body,
the method comprising:
a process of preparing a plurality of balance weights, weights of which are different from each other and at least inner side surfaces of which are each covered with the first cover layer;
a process of determining a fixing position of the balance weight to the tubular body and weight of the balance weight according to a rotation imbalance of the power transmission shaft;
a process of welding the determined balance weight to the uncovered portion of the tubular body through the projecting portion; and
a process of forming the second cover layer on the outer peripheral surface of the tubular body and the outer side surface of the balance weight by coating the tubular body including the balance weight.

6. The method of manufacturing the power transmission shaft as claimed in claim 5 , wherein:
the balance weight is curved at a curvature corresponding to a curvature of the outer peripheral surface of the tubular body.

7. The method of manufacturing the power transmission shaft as claimed in claim 5 , wherein:
the balance weight is formed by stamping out a band-shaped material that is plated with the first cover layer.

8. The method of manufacturing the power transmission shaft as claimed in claim 5 , wherein:
the balance weight is formed by, after stamping out a band-shaped material, coating a stamped material with the first cover layer.

9. The method of manufacturing the power transmission shaft as claimed in claim 5 , wherein:
an entire surface of the balance weight is covered with the first cover layer.

10. A method of manufacturing a power transmission shaft, the power transmission shaft having;
a tubular body made of iron-based metal; and
a balance weight having;
a rivet made of iron-based metal and fixed to the tubular body, and
a weight body made of iron-based metal and having a penetration hole which the rivet penetrates, wherein at least a part of the weight body is covered with sacrificial corrosion prevention material that contains metal whose ionization tendency is higher than that of metal forming the tubular body,

wherein the balance weight is fixed to an outer peripheral surface of the tubular body with the rivet,
the method comprising:
preparing a plurality of weight bodies, weights of which are different from each other;
determining a fixing position of the weight body to the tubular body and a weight of the weight body according to a rotation imbalance of the power transmission shaft;
fixing the rivet to the fixing position of the weight body to the tubular body;
fixing the weight body to the tubular body by making the rivet penetrate the penetration hole of the weight body and riveting the rivet having penetrated the penetration hole; and
forming a second cover layer on the outer peripheral surface of the tubular body and an outer side surface of the balance weight by coating the tubular body including the balance weight.

11. A power transmission shaft comprising:
a tubular body made of iron-based metal;
a balance weight having;
a rivet made of iron-based metal and fixed to the tubular body, and
a weight body made of iron-based metal and having a penetration hole which the rivet penetrates,
wherein the balance weight is fixed to an outer peripheral surface of the tubular body with the rivet; and

a sacrificial metal formed, as a different member from the balance weight, with a plate-shaped metal material whose ionization tendency is higher than that of metal forming the tubular body and having a penetration hole which the rivet penetrates, wherein the sacrificial metal is fixed to the outer peripheral surface of the tubular body with the rivet with the sacrificial metal being in contact with a surface of the weight body,
wherein the weight body and the sacrificial metal are both fixed to the outer peripheral surface of the tubular body with the rivet penetrating the penetration holes being riveted.

12. The power transmission shaft as claimed in claim 11 , wherein:
the sacrificial metal is provided between the tubular body and the balance weight.

13. The power transmission shaft as claimed in claim 11 , wherein:
the sacrificial metal is made of zinc, magnesiu

Assignees

• Hitachi Automotive Systems Ltd
• Hitachi Astemo Ltd

Inventors

• Mabe Yasutomo
• Nakane Kiyokazu
• Komai Hiromichi
• Zhu Xiaojin
• Masuda Toshiyuki
• Ishikura Kenichiro

Classifications

• F16C15/00

  Construction of rotary bodies to resist centrifugal force (flywheels, correction weights F16F15/30, F16F15/32) · CPC title

• B21D28/26

  in sheets or flat parts · CPC title

• C09D1/00

  Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances · CPC title

• F16C11/06 Primary

  Ball-joints; Other joints having more than one degree of angular freedom, i.e. universal joints (universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts F16D3/16) · CPC title

• F16C2300/42

  corrosive, i.e. with aggressive media or harsh conditions · CPC title