# US 8,770,362 B2 · Hydrodynamic retarder

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- Number: US 8,770,362 B2
- Document ID: US8770362B2
- Status: Granted
- Kind: B2
- Application number: 12/602,558
- Filed: 2008-05-19
- Published: 2010-07-29
- Granted: 2014-07-08
- Earliest claimed: 2007-06-01
- Assignees: ZF Friedrichshafen AG
- Applicants: Christian Selinka; Reinhold Mayer; Thomas Meid; Dirk Huhn; Michael Ptock; Michael Huber
- Inventors: Christian Selinka; Reinhold Mayer; Thomas Meid; Dirk Huhn; Michael Ptock; Michael Huber
- Web page: https://patentgrep.com/patent/US8770362B2

## CPC

- F16D 57/04: with blades causing a directed flow, e.g. Föttinger type
- B60T 10/02: with hydrodynamic brake
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES

## Abstract

A hydrodynamic retarder having a first blade wheel and having a second blade wheel concentric thereto, together forming a hydrodynamic circuit grouped about a common rotary axis. Each blade wheel is made of a base body and a blade arrangement fixed thereto including a plurality of blades. The hydrodynamic circuit is supplied by a fluid inlet, while the fluid removal from the hydrodynamic circuit is performed by a fluid outlet. The fluid inlet has an inlet spiral enabling tangential fluid flow and the fluid outlet has an outlet spiral enabling tangential fluid flow. At least one inlet spiral is associated with a flow guide guiding the fluid into the hydrodynamic circuit with at least one axial component.

## Claims

### Claim 1

A hydrodynamic retarder comprising:
a first blade wheel comprising a first base body and a plurality of first blades permanently attached to the first base body; and
a second blade wheel comprising a second base body and a plurality of second blades permanently attached to the second base body, the second blade wheel being concentric to the first blade wheel, the first and second blade wheels configured to form a hydrodynamic circuit and arranged around a common axis of rotation;
a fluid inlet configured to supply fluid to the hydrodynamic circuit, the fluid inlet comprising an inlet spiral configured to create a tangential fluid flow;
a fluid outlet configured to discharge fluid from the hydrodynamic circuit, the fluid outlet comprising an outlet spiral configured to create a tangential fluid flow; and
a flow guide configured to introduce the fluid into the hydrodynamic circuit comprising at least one axial component assigned at least to the inlet spiral,
wherein the inlet spiral is arranged radially inside the hydrodynamic circuit and the outlet spiral is arranged radially outside the hydrodynamic circuit,
wherein the flow guide is provided as an axial projection on the first base body and projects beyond the external contour of the first blade wheel toward the second blade wheel, the axial projection configured to engage in a recess in the second blade wheel,
wherein the flow guide is configured as a stator blade wheel and the second base body is configured as a rotor blade wheel, and
the flow guide is configured to engage in the recess in the rotor blade wheel
wherein the first base body has an arcuate contour and the axial projection continues the arcuate contour so that the axial projection projects away from the axis of rotation.

### Claim 2 (depends on 1)

The hydrodynamic retarder according to claim 1, wherein the flow guide defines a flow route between the inlet spiral and the hydrodynamic circuit, and the inlet spiral is separated from the hydrodynamic circuit by the flow guide except for the width of the flow route.

### Claim 3 (depends on 2)

The hydrodynamic retarder according to claim 2, wherein the width of the flow route is configured to be reduced to a slit.

### Claim 4 (depends on 1)

The hydrodynamic retarder according to claim 1, wherein the axial projection of the first base body is provided in a radially inner area of the first base body with a free axial end of the axial projection configured to approach the second blade wheel to form a flow path.

### Claim 5 (depends on 4)

The hydrodynamic retarder according to claim 4, wherein the axial projection of the flow guide on the first base body comprises an extension extending in a radial direction configured so that the direction of the fluid flow coming from the inlet spiral has a component in the radial direction.

### Claim 6 (depends on 1)

The hydrodynamic retarder according to claim 1, wherein the blading of the second blade wheel, is provided with a setback in the individual blades, which forms the recess in the area of the radial extension of a free axial end of the axial projection.