Worm wheel of steering system speed reducer, and manufacturing method therefor

Patent metadata

Field	Value
Publication number	US-12103606-B2
Application number	US-202017640328-A
Country	US
Kind code	B2
Filing date	Sep 2, 2020
Priority date	Sep 3, 2019
Publication date	Oct 1, 2024
Grant date	Oct 1, 2024

Abstract

The present embodiments relate to a worm wheel of a steering system speed reducer, and provide a worm wheel of a steering system speed reducer, and a manufacturing method therefor, the worm wheel comprising: an external toothed part having a ring shape, external gear teeth provided on the outer peripheral side thereof, insertion grooves provided on the inner peripheral side thereof, and coupling holes provided on the upper surface and/or the lower surface thereof; an internal toothed part, which has a ring shape, is inserted into the external toothed part, has insertion protrusions provided on the outer peripheral side thereof, and has coupling protrusions provided at locations corresponding to the coupling holes; a hub to which a steering shaft is coupled; and a boss part provided between the outer peripheral side of the hub and the inner peripheral side of the external toothed part.

First claim

The invention claimed is:

1. A worm wheel of a steering device reducer, comprising:
an outer toothed part having a ring shape provided with outer gear teeth engaged with gear teeth of a worm shaft on an outer circumferential side thereof and insertion recesses radially depressed and circumferentially spaced apart from each other on an inner circumferential side thereof and having a coupling hole in any one of an upper surface and lower surface thereof;
an inner toothed part having a ring shape inserted into an inside of the outer toothed part and provided with insertion protrusions fitted into the insertion recesses, on an outer circumferential side thereof and a cylindrical coupling protrusion in a position corresponding to the coupling hole to be coupled to the coupling hole;
a hub to which a steering shaft is coupled; and
a boss part provided between an outer circumferential side of the hub and an inner circumferential side of the outer toothed part,
wherein the outer toothed part has a support recess in an inner circumferential surface of a portion thereof connected with the insertion recesses.

2. The worm wheel of claim 1 , wherein the inner toothed part has a support protrusion formed on an upper surface or lower surface adjacent to the inner circumferential surface to protrude upward to be inserted into the support recess.

3. The worm wheel of claim 2 , wherein the support recess is formed in each of an upper side and lower side connected with the insertion recesses, wherein a plurality of support recesses are arranged to be circumferentially spaced apart from each other, and wherein the support protrusion is formed in a position corresponding to the support recess on each of an upper surface and lower surface adjacent to the inner circumferential surface of the inner toothed part.

4. A worm wheel of a steering device reducer, comprising:
an outer toothed part having a ring shape provided with outer gear teeth engaged with gear teeth of a worm shaft on an outer circumferential side thereof and insertion recesses radially depressed and circumferentially spaced apart from each other on an inner circumferential side thereof and having at least one coupling hole in at least one of an upper surface and lower surface thereof;
an inner toothed part having a ring shape inserted into an inside of the outer toothed part and provided with insertion protrusions fitted into the insertion recesses, on an outer circumferential side thereof and at least one cylindrical coupling protrusion protruding from at least one of an upper surface and lower surface of the inner toothed part in an axial direction and a position corresponding to the at least one coupling hole to be coupled to the at least one coupling hole;
a hub to which a steering shaft is coupled; and
a boss part provided between an outer circumferential side of the hub and an inner circumferential side of the outer toothed part,
wherein the at least one coupling hole is formed in an arc shape, wherein the at least one coupling hole comprises a plurality of coupling holes arranged on the upper surface or lower surface to be spaced apart from each other, and wherein the at least one coupling protrusion is formed to protrude in an arc shape corresponding to the at least one coupling hole.

5. The worm wheel of claim 1 , wherein an outer circumferential surface of the coupling protrusion and an inner circumferential surface of the coupling hole contact each other.

6. The worm wheel of claim 5 , wherein an end of the coupling protrusion is positioned on a same plane as the upper surface or lower surface, provided with the coupling hole, of the outer toothed part.

7. The worm wheel of claim 1 , wherein an end of the coupling protrusion is positioned on a same plane as the upper surface or lower surface, provided with the coupling hole, of the outer toothed part.

8. The worm wheel of claim 1 , wherein an outer surface of the coupling protrusion and an inner surface of the coupling hole fit each other in contact.

9. The worm wheel of claim 1 , wherein the coupling hole of the outer toothed part is formed in an upper or lower direction to communicate with the insertion recesses.

10. The worm wheel of claim 4 , wherein the inner toothed part has a fixing protrusion formed, as an inclined surface, on at least one of an upper end and lower end of the inner circumferential surface, and wherein a plurality of fixing recesses circumferentially spaced apart from each other are formed in the fixing protrusion.

11. A method for manufacturing a worm wheel of a steering device, the method comprising:
providing an outer toothed part having a ring shape provided with outer gear teeth engaged with gear teeth of a worm shaft on an outer circumferential side thereof and insertion recesses radially depressed and circumferentially spaced apart from each other on an inner circumferential side thereof and having at least one coupling hole in at least one of an upper surface and lower surface thereof;
providing an inner toothed part having a ring shape inserted into an inside of the outer toothed part and provided with insertion protrusions fitted into the insertion recesses, on an outer circumferential side thereof and at least one cylindrical coupling protrusion protruding from at least one of an upper surface and lower surface of the inner toothed part in an axial direction and a position corresponding to the at least one coupling hole to be coupled to the at least one coupling hole;
coupling a steering shaft to a hub; and
providing a boss part between an outer circumferential side of the hub and an inner circumferential side of the outer toothed part,
wherein the at least one coupling hole is formed in an arc shape, wherein the at least one coupling hole comprises a plurality of coupling holes arranged on the upper surface or lower surface to be spaced apart from each other, and wherein the at least one coupling protrusion is formed to protrude in an arc shape corresponding to the at least one coupling hole.

12. The method of claim 11 , wherein an outer circumferential surface of the coupling protrusion and an inner circumferential surface of the coupling hole contact each other.

13. The method of claim 12 , wherein an end of the coupling protrusion is positioned on a same plane as the upper surface or lower surface, provided with the coupling hole, of the outer toothed part.

14. The method of claim 11 , wherein an end of the coupling protrusion is positioned on a same plane as the upper surface or lower surface, provided with the coupling hole, of the outer toothed part.

15. The method of claim 11 , wherein an outer surface of the coupling protrusion and an inner surface of the coupling hole fit each other in contact.

16. The method of claim 11 , wherein the coupling hole of the outer toothed part is formed in an upper or lower direction to communicate with the insertion recesses.

17. The method of claim 11 , wherein the outer toothed part has a support recess in an inner circumferential surface of a portion thereof connected with the insertion recesses.

18. The method of claim 11 , wherein the inner toothed part has a fixing protrusion formed, as an inclined surface, on at least one of an upper end and lower end of the inner circumferential surface, and wherein a plurality of fixing recesses circumferentially spaced apart from each other are formed in the fixing protrusion.

Assignees

• Hl Mando Corp

Inventors

• Kim Jong Han

Classifications

• B29D15/00

  Producing gear wheels or similar articles with grooves or projections, e.g. control knobs · CPC title

• F16H2055/065

  Moulded gears, e.g. inserts therefor · CPC title

• B29L2015/003

  Gears · CPC title

• B29L2031/7754

  Worms · CPC title

• B29C45/0003

  of successively moulded portions rigidly joined to each other · CPC title