# US 2021/0277535 A1 · Electrode for an eloxal process

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- Number: US 2021/0277535 A1
- Document ID: US20210277535A1
- Status: Published application
- Kind: A1
- Application number: 17/054,066
- Filed: 2019-04-02
- Published: 2021-09-09
- Earliest claimed: 2018-05-07
- Assignees: ZF Active Safety GmbH
- Applicants: ZF Active Safety GmbH
- Inventors: Dennis Monpetit
- Web page: https://patentgrep.com/patent/US20210277535A1

## CPC

- C25D 17/12: Shape or form (C25D17/14 takes precedence)
- C25D 11/005: {Apparatus specially adapted for electrolytic conversion coating (apparatus in general for electrolytic coating C25D17/00)}
- C25D 11/022: {Anodisation on selected surface areas}
- C25D 11/08: containing inorganic acids
- C25D 21/02: Heating or cooling
- C25D 11/10: containing organic acids
- C25D 17/02: Tanks; Installations therefor
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR

## Abstract

The present disclosure relates to an electrode for eloxing a component, in particular a component of a vehicle brake system, comprising an electrolyte inlet for feeding an electrolyte into the electrode, an inlet channel, which connects the electrolyte inlet to an electrolyte outlet opening formed in the region of an outer surface of the electrode, an electrolyte inlet opening formed in the region of the outer surface of the electrode at a distance from the electrolyte outlet opening, an electrolyte flow path, which runs between the electrolyte outlet opening and the electrolyte inlet opening along the outer surface of the electrode and is designed to bring a surface portion of the component, which surface portion is to be eloxed, into fluid contact with the electrolyte flowing through the electrolyte flow path, an outlet channel, and an electrolyte outlet.

## Claims

### Claim 1

An electrode for anodizing a component, in particular a component of a vehicle braking system, comprising:
an electrolyte inlet for feeding an electrolyte into the electrode,
an inlet channel which connects the electrolyte inlet to an electrolyte exit opening formed in the region of an outer surface of the electrode,
an electrolyte entry opening formed in the region of the outer surface of the electrode spaced apart from the electrolyte exit opening,
an electrolyte flow path that runs between the electrolyte exit opening and the electrolyte entry opening along the outer surface of the electrode and is adapted to bring a surface section of the component to be anodized into fluid contact with the electrolyte flowing through the electrolyte flow path,
an outlet channel connected to the electrolyte entry opening and
an electrolyte outlet connected to the outlet channel for discharging the electrolyte from the electrode.

### Claim 2 (depends on 1)

The electrode as claimed in claim 1,
wherein the electrolyte inlet, the inlet channel, the electrolyte outlet opening, the electrolyte flow path, the electrolyte entry opening, the outlet channel and/or the electrolyte outlet is/are shaped and/or dimensioned such that a laminar electrolyte flow is established at least in the electrolyte flow path.

### Claim 3 (depends on 2)

The electrode as claimed in claim 2, wherein the inlet channel comprises one of:
a plurality of inlet channel branches each connected to an electrolyte exit opening, and
an inlet channel section arranged upstream of the inlet channel branches, wherein the inlet channel branches and/or the electrolyte exit openings are preferably arranged equidistantly in the circumferential direction of the electrode,
wherein the outlet channel comprises:
a plurality of outlet channel branches each connected to an electrolyte entry opening, or
an outlet channel section arranged downstream of the outlet channel branches, wherein the electrolyte entry openings and/or the outlet channel branches are preferably arranged equidistantly in the circumferential direction of the electrode.

### Claim 4 (depends on 3)

The electrode as claimed in claim 3, wherein:
the number of inlet channel branches corresponds to the number of outlet channel branches, and/or
the number of electrolyte exit openings corresponds to the number of electrolyte entry openings.

### Claim 5 (depends on 4)

The electrode as claimed in claim 4, wherein:
the inlet channel section and the outlet channel section have the same flow cross sections, and/or
the inlet channel branches, the electrolyte outlet openings, the electrolyte inlet openings and/or the outlet channel branches have identical flow cross sections.

### Claim 6 (depends on 5)

The electrode as claimed in claim 5, wherein:
the flow cross section of the inlet channel section corresponds to the sum of the flow cross sections of the inlet channel branches, and
the flow cross section of the outlet channel section corresponds to the sum of the flow cross sections of the outlet channel branches.

### Claim 7 (depends on 6)

The electrode as claimed in claim 6, comprising
a first electrode part having:
a cylindrical first section adapted for introduction into a recess formed in the component to be anodized, in whose outer surface the electrolyte exit opening and the electrolyte entry opening are formed spaced apart from one another along the longitudinal axis of the electrode and/or along whose outer surface the electrolyte flow path runs, and/or
a flange section extending radially from the outer surface of the first section, wherein in the region of a first end face facing the component to be anodized during operation of the electrode the flange section preferably carries a seal which is adapted to seal an electrolysis gap defined by the outer surface of the first section and an inner surface of the recess formed in the component to be anodized during operation of the electrode, and/or
a further cylindrical section extending along the longitudinal axis of the electrode from a second end face of the flange section which faces away from the component to be anodized during operation of the electrode.

### Claim 8 (depends on 7)

The electrode as claimed in claim 7, wherein:
the first electrode part is penetrated by a through-bore extending along the longitudinal axis of the electrode, wherein a section of the through-bore especially forms the outlet channel section and/or wherein the through-bore is fluid-tightly sealed by means of a further seal in the region of an end facing the component to be anodized during operation of the electrode, and/or
inlet channel branches formed in the first electrode part extend from the second end face of the flange section in the flow direction of the electrolyte flowing through the inlet channel branches initially inclined radially inwardly to the electrolyte exit openings relative to the longitudinal axis of the electrode and subsequently inclined radially outwardly to the electrolyte exit openings relative to the longitudinal axis of the electrode, and/or
outlet channel branches formed in the first electrode part extend radially inwardly from the electrolyte entry openings, preferably substantially parallel to the sections of the inlet channel branches inclined radially outwardly relative to the longitudinal axis of the electrode, and in particular open into the through-bore penetrating the first electrode part.

### Claim 9 (depends on 8)

The electrode as claimed in claim 8, comprising
a second electrode part in particular adjacent to the first electrode part, wherein
the second electrode part is penetrated by a through-bore extending along the longitudinal axis of the electrode which is especially adapted to accommodate the further cylindrical section of the first electrode part, and
an inlet channel section formed in the second electrode part which preferably has a ring-shaped flow cross section extends substantially parallel to the longitudinal axis of the electrode from a first end face of the second electrode part facing the component to be anodized during operation of the electrode in the direction of a second end face of the second electrode part facing away from the component to be anodized during operation of the electrode, and
in the second electrode part a first connecting channel connected to the electrolyte inlet is formed which extends in particular substantially perpendicularly to the longitudinal axis of the electrode and/or forms a fluid-conducting connection between the electrolyte inlet formed in the region of an outer surface of the second electrode part and the inlet channel section formed in the second electrode part.

### Claim 10 (depends on 9)

The electrode as claimed in claim 9, comprising
a third electrode part in particular adjacent to the second electrode part having:
a main body and
a cylindrical protruding section which extends along the longitudinal axis of the electrode and during operation of the electrode projects in the direction of the component to be anodized and especially adjacent to the further cylindrical section of the first electrode part is accommodated in the through-bore penetrating the second electrode part, wherein
in the third electrode part a second connection channel connected to the electrolyte outlet is formed which comprises a first section which penetrates the protruding section along the longitudinal axis of the electrode and a second section running in particular substantially perpendicularly to the longitudinal axis of the electrode in the region of the main body and/or forms a fluid-conducting connection between the electrolyte outlet formed in the region of an outer surface of the third electrode part and the outlet channel section formed in the first electrode part.

### Claim 11

An apparatus for anodizing a component, in particular a component of a vehicle braking system, comprising:
an electrode further including:
an electrolyte inlet for feeding an electrolyte into the electrode,
an inlet channel which connects the electrolyte inlet to an electrolyte exit opening formed in the region of an outer surface of the electrode,
an electrolyte entry opening formed in the region of the outer surface of the electrode spaced apart from the electrolyte exit opening,
an electrolyte flow path that runs between the electrolyte exit opening and the electrolyte entry opening along the outer surface of the electrode and is adapted to bring a surface section of the component to be anodized into fluid contact with the electrolyte flowing through the electrolyte flow path,
an outlet channel connected to the electrolyte entry opening and
an electrolyte outlet connected to the outlet channel for discharging the electrolyte from the electrode;
an electrolyte circuit for feeding electrolyte to the electrode and for discharging electrolyte from the electrode, wherein arranged in the electrolyte circuit are in particular an electrolyte source and/or a conveying means for conveying the electrolyte through the electrolyte circuit, and
a voltage source which is connectable to the component to be anodized and the electrode and is adapted for applying opposite voltages to the component and the electrode.

### Claim 12 (depends on 11)

The apparatus as claimed in claim 11, further comprising a cooling apparatus for cooling the electrode, the component and/or the electrolyte, wherein the cooling apparatus is especially arranged in the electrolyte circuit and is adapted for cooling the electrolyte flowing through the electrolyte circuit.

### Claim 13

A process for anodizing a component, in particular a component of a vehicle braking system, comprising the steps of:
supplying an electrolyte to an electrode through an electrolyte inlet,
passing the electrolyte through an inlet channel which connects the electrolyte inlet to an electrolyte exit opening formed in the region of an outer surface of the electrode,
passing the electrolyte through an electrolyte entry opening formed in the region of the outer surface of the electrode spaced apart from the electrolyte exit opening,
passing the electrolyte through an electrolyte flow path running between the electrolyte exit opening and the electrolyte entry opening along the outer surface of the electrode, wherein the electrolyte is brought into fluid contact with a surface section of the component to be anodized upon flowing through the electrolyte flow path,
passing the electrolyte through an outlet channel connected to the electrolyte entry opening,
discharging the electrolyte from the electrode through an electrolyte outlet connected to the outlet channel and
applying opposite voltages to the component to be anodized and the electrode.

### Claim 14 (depends on 13)

The process as claimed in claim 13, wherein:
the temperature of the electrolyte is set to −10° C. to +20° C.,
the voltage is increased from 0 V to a maximum voltage of 30 V over a defined period, so that in this period the current increases from 0 A to a current which is higher than 0 A but not more than 2 A and/or
the electrolyte, the electrode and/or the component are cooled to remove heat formed during the anodization.

### Claim 15 (depends on 14)

The process as claimed in claim 14, wherein a cylindrical first section of a first electrode part, in whose outer surface the electrolyte exit opening and the electrolyte entry opening are formed spaced apart from one another along a longitudinal axis of the electrode and/or along whose outer surface the electrolyte flow path runs, is introduced into a recess formed in the component to be anodized.

### Claim 16

(canceled)

### Claim 17

(canceled)