Commutator

• US 20060087195A1
• Filed: 05/16/2003
• Published: 04/27/2006
• Est. Priority Date: 05/18/2002
• Status: Active Grant

• Current Assignee: Johnson Electric SA 125 Rue de Progres La Chaux de Fonds Switzerland (Johnson Electric Holdings Limited)
• Original Assignee: Johnson Electric SA 125 Rue de Progres La Chaux de Fonds Switzerland (Johnson Electric Holdings Limited)
• Inventors: Gorlt, Wilfried
• Granted Patent: US 7,485,998 B2
• Time in Patent Office: Days
• US Class Current: 310/237
• CPC Class Codes: H01R 39/045 the commutators being made of carbon
• CPC Class Codes: H01R 43/06 Manufacture of commutators
• CPC Class Codes: Y10T 29/49011 Commutator or slip ring assembly

Abstract

A commutator comprises a commutator base 10 of insulating material, a plurality of commutator terminals 20 each of which has a terminal portion 21 and a contact portion 22 and a plurality of carbon segments 30 formed on the base and over the contact portions, respectively, of the terminal. Each carbon segment has an inner portion 31 of molded graphite material adjacent to the base and one or more outer exposed portions 32 containing or formed of sintered graphite.

Claims

1. A commutator comprising a commutator base of insulating material, a plurality of commutator terminals each of which comprises a terminal portion and a contact portion and a plurality of carbon segments formed on the base and over the contact portions, respectively, of the terminals wherein each carbon segment has an inner portion of molded graphite adjacent to the base and at least one exposed outer portion containing or formed of sintered graphite.

2. A commutator as claimed in claim 1, wherein each carbon segment comprises a first inner layer of molded graphite forming the inner portion and a second outer layer of molded graphite containing sintered graphite particles forming the outer portion.

3. A commutator as claimed in claim 1, wherein each carbon segment comprises a first inner layer of molded graphite forming the inner portion and a second outer layer of sintered graphite forming the outer portion.

4. A commutator as claimed in claim 3, wherein the second outer layer includes parts which project into the first inner layer.

5. A commutator as claimed in claim 1, wherein each commutator segment comprises a layer of molded graphite forming the said inner portion and at least one sintered graphite elements embedded in the said first portion and forming the said outer portions.

6. A commutator as claimed in claim 1, in the form of a planar commutator.

7. A commutator as claimed in claim 6, wherein the base has a rotational axis and front and rear surfaces extending, at least in part, transversely to the rotational axis and wherein the contact portion of each terminal extends through a respective first aperture in the base and is bent to lie against or in close proximity to the front surface of the base and the terminal portion of each terminal has a cutting edge for cutting insulation on a connector portion of a winding and a slot which, in use, straddles and grips the said connector portion.

8. A commutator as claimed in claim 6, wherein each carbon segment comprises a first inner layer of molded graphite forming the inner portion and a second outer layer of sintered graphite forming the outer portion and wherein the second outer layers of the carbon segments define a disc split radially to form the individual commutator segments.

9. A commutator as claimed in claim 6, wherein each commutator segment comprises a layer of molded graphite forming the inner portion and a plurality of sintered graphite elements embedded in the first portion and forming the said outer portions and wherein the sintered graphite elements are part circular and arranged concentrically with respect to the rotational axis of the base.

10. A commutator as claimed in claim 1, in the form of a cylindrical commutator.

11. A method of making a planar commutator comprising a commutator base of insulating material, a plurality of commutator terminals each of which comprises a terminal portion and a contact portion and a plurality of carbon segments formed on the base and over the contact portions, respectively, of the terminals wherein each carbon segment comprises a first inner layer of molded graphite adjacent to the base and a second outer layer of molded graphite containing sintered graphite particles, the method comprising the steps of:

—

(a) cold pressing together a layer of moldable graphite and a layer of moldable graphite containing sintered graphite particles to form a disc,

(b) connecting the terminals to the base, then

(c) molding the disc to the base, then

(d) dividing the disc into a plurality of commutator segments.

12. A method of making a planar commutator comprising a commutator base of insulating material, a plurality of commutator terminals each of which comprises a terminal portion and a contact portion and a plurality of carbon segments formed on the base and over the contact portions, respectively, of the terminals wherein each carbon segment comprises an inner layer of molded graphite adjacent to the base and a second outer layer of sintered graphite, the method comprising the steps of:

—

(a) forming a disc of sintered graphite,

(b) connecting the terminals to the base, and then

(c) molding the disc of sintered graphite to the base with a layer of moldable graphite therebetween, then

(d) dividing the molded and sintered graphite layers into a plurality of commutator segments.

13. A method of making a planar commutator comprising a commutator base of insulating material, a plurality of commutator terminals each of which comprises a terminal portion and a contact portion and a plurality of carbon segments formed on the base and over the contact portions, respectively, of the terminals wherein each carbon segment comprises a layer of molded graphite adjacent to the base and a plurality of sintered graphite elements embedded in the said molded graphite layer, the method comprising the steps of:

—

(a) forming a plurality of circular elements of sintered graphite, the elements being of different diameters,

(b) connecting the terminals to the base, and then

(c) molding the circular elements in spaced apart concentric manner to the base with a layer of moldable graphite, and then

(d) dividing the molded graphite and sintered graphite elements into a plurality of commutator segments.