IP Library › Granted Patent US 12668345
Granted Patent B1
US 12668345 · App. 18/630,210 · Granted Jun 30, 2026

Gearcases for marine drives and methods of making gearcases for marine drives having reduced noise output

Inventors: Joshua S. Smith (Mayville, WI); Jeffrey Chiang (Oshkosh, WI); Theodore J. Hanes (Fond du Lac, WI); Brett Bielefeld (Oshkosh, WI); David A. Kobilic (Oakfield, WI)
Assignee: Brunswick Corporation
B63H23/06B63H21/36B63H21/38B63H23/321B63H23/34B22D19/0036B29C39/10B29K2307/04B29K2309/08B29K2705/02
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Quick Facts
Patent No.
US 12668345
App. No.
18/630,210
Granted
Jun 30, 2026
Kind
B1
Abstract

A gearcase for a marine drive, the gearcase having a housing made of a first material, a driveshaft extending into the housing, a propulsor shaft extending from the housing, a gearset rotationally coupling the driveshaft to the propulsor shaft such that rotation of the driveshaft causes rotation of the propulsor shaft, and a stiffening insert made of a second material that is stiffer than the first material, the stiffening insert reinforcing the housing in a manner that limits gear misalignment that would otherwise occur based on gear forces and applied loads on the gearset. Stiffening inserts and methods of manufacturing a gearcase having a stiffening insert are also provided.

Claims (28)

1 . A gearcase for a marine drive, the gearcase comprising:

a housing made of a first material;

a driveshaft extending into the housing;

a propulsor shaft extending from the housing;

a gearset rotationally coupling the driveshaft to the propulsor shaft such that rotation of the driveshaft causes rotation of the propulsor shaft; and

a stiffening insert made of a second material that is stiffer than the first material, the stiffening insert reinforcing the housing in a manner that limits gear misalignment caused by gear forces and applied loads on the gearset wherein the stiffening insert comprises a monolithic body having a first lobe that surrounds the driveshaft and a second lobe that surrounds the propulsor shaft.

2 . The gearcase according to claim 1 , further comprising a driveshaft bearing supporting rotation of the driveshaft relative to the gearcase, wherein the stiffening insert is positioned between the driveshaft bearing and the housing.

3 . The gearcase according to claim 2 , wherein the stiffening insert surrounds the driveshaft bearing.

4 . The gearcase according to claim 2 , wherein the driveshaft bearing comprises a roller bearing and further wherein the stiffening insert and the roller bearing are separate pieces.

5 . The gearcase according to claim 1 , further comprising a propulsor shaft bearing supporting rotation of the propulsor shaft relative to the housing, wherein the stiffening insert is positioned between the propulsor shaft bearing and the housing.

6 . The gearcase according to claim 5 , wherein the stiffening insert surrounds the propulsor shaft bearing.

7 . The gearcase according to claim 5 , wherein the propulsor shaft bearing comprises a roller bearing and further wherein the stiffening insert and the roller bearing are separate pieces.

8 . The gearcase according to claim 5 , wherein the gearset comprises a drive gear on the driveshaft and a driven gear on the propulsor shaft, and further comprising a driven gear bearing supporting rotation of the driven gear relative to the propulsor shaft, and wherein the stiffening insert is positioned between the driven gear bearing and the housing.

9 . The gearcase according to claim 8 , further comprising a clutch configured to operatively engage the driven gear with the propulsor shaft such that rotation of the driven gear causes rotation of the propulsor shaft, and wherein the propulsor shaft bearing supports rotation of the driven gear and the propulsor shaft relative to the housing when the driven gear is operatively engaged with the propulsor shaft.

10 . The gearcase according to claim 5 , wherein the propulsor shaft bearing is a first propulsor shaft bearing supporting rotation of the propulsor shaft relative to the housing, and further comprising a second propulsor shaft bearing supporting rotation of the propulsor shaft relative to the housing, and wherein the stiffening insert is positioned between the first propulsor shaft bearing and the housing, and between the second propulsor shaft bearing and the housing.

11 . The gearcase according to claim 10 , wherein the gearset comprises a drive gear on the driveshaft, a first driven gear on the propulsor shaft, and a second driven gear on the propulsor shaft, and further comprising a first driven gear bearing supporting rotation of the first driven gear relative to the propulsor shaft and a second driven gear bearing supporting rotation of the second driven gear relative to the propulsor shaft, and wherein the stiffening insert is positioned between the first driven gear bearing and the housing, and between the second driven gear bearing and the housing.

12 . The gearcase according to claim 11 , wherein the stiffening insert surrounds the first driven gear bearing and the second driven gear bearing.

13 . The gearcase according to claim 12 , further comprising a driveshaft bearing supporting rotation of the driveshaft relative to the gearcase, wherein the stiffening insert surrounds the driveshaft bearing.

14 . The gearcase according to claim 1 , further comprising a driveshaft bearing supporting rotation of the driveshaft relative to the gearcase and a propulsor shaft bearing supporting rotation of the propulsor shaft relative to the housing, wherein the stiffening insert is positioned between the driveshaft bearing and the housing, and between the propulsor shaft bearing and the housing.

15 . The gearcase according to claim 14 , wherein the stiffening insert surrounds the driveshaft bearing and the propulsor shaft bearing.

16 . The gearcase according to claim 1 , wherein the first lobe surrounds a driveshaft bearing supporting rotation of the driveshaft relative to the housing and wherein the second lobe surrounds a propulsor shaft bearing supporting rotation of the propulsor shaft relative to the housing.

17 . The gearcase according to claim 16 , further comprising at least one arm that couples the first lobe to the second lobe.

18 . The gearcase according to claim 17 , wherein the at least one arm is one of a pair of arms and further wherein a through-bore passage facilitating supply of lubrication to the housing is defined between the pair of arms.

19 . A method of manufacturing the gearcase according to claim 1 , comprising casting the housing with the stiffening insert in the housing.

20 . The method according to claim 19 , comprising heating the stiffening insert prior to casting.

21 . The method according to claim 19 , comprising controlling temperature of the housing and the stiffening insert such that once the gearcase is formed the stiffening insert applies a pre-stress on the gearcase.

22 . The method according to claim 19 , comprising selecting an ideal pre-stress on the gearcase for limiting noise of the gearcase, and then controlling temperature of the housing and the stiffening insert such that once the gearcase is formed stiffening insert applies the ideal pre-stress on the gearcase.

23 . The method according to claim 19 , comprising providing the stiffening insert with grooves that form a mechanical bond with the housing during said casting.