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US 8,783,409 B2Granted
Rack driven electric power steering apparatus
AssigneeMando Corporation
InventorsJe Ho Lee, Nam Hwan Heo
Life of this patent
Estimating the term…
Abstract
Disclosed is a rack driven electric power steering apparatus in which balls can be introduced in a state where end caps are assembled within a ball nut, impact noise and friction noise can be reduced when the balls circulate, and a separate assembling device for injection of the balls is not required, making it possible to shorten a manufacturing and assembling process.
Claims12
A rack driven electric power steering apparatus comprising:
- a rack bar having an outer screw groove on an outer peripheral surface thereof;
- a ball nut having an inner screw groove corresponding to the outer screw groove of the rack bar on an inner peripheral surface thereof to be coupled to the rack bar by means of balls and having a ball circulating passage axially passing through the ball nut between an inner peripheral surface and an outer peripheral surface thereof;
- a pair of end caps each having a ball introducing passage, one side of which is communicated with the ball circulating passage and an opposite side of which is communicated with the outer screw groove of the rack bar and the inner screw groove of the ball nut, and coupled to opposite inner ends of the ball nut;
- and
- a pair of end cap rings selectively coupled to outer sides of the end caps respectively to prevent separation of the balls,
- wherein the ball introducing passage of the end cap extends in a fork-shaped curved form from a portion where the ball introducing passage is communicated with the ball circulating passage of the ball nut to a portion where it is communicated with the outer screw groove and the inner screw groove, whereby the balls circulate and are introduced smoothly.
3 more elements
A rack driven electric power steering apparatus comprising:
- a rack bar having an outer screw groove on an outer peripheral surface thereof;
- a ball nut having an inner screw groove corresponding to the outer screw groove of the rack bar on an inner peripheral surface thereof to be coupled to the rack bar by means of balls and having a ball circulating passage axially passing through the ball nut between an inner peripheral surface and an outer peripheral surface thereof;
- a pair of end caps each having a ball introducing passage, one side of which is communicated with the ball circulating passage and an opposite side of which is communicated with the outer screw groove of the rack bar and the inner screw groove of the ball nut, and coupled to opposite inner ends of the ball nut;
- and
- a pair of end cap rings coupled to outer sides of the end caps respectively to prevent separation of the balls,
- wherein each of the end caps has a ball introducing hole passing through the ball introducing passage in a direction where the ball introducing hole is communicated with the ball circulating passage, and wherein each of the end cap rings has a protrusion protruding axially from one side surface thereof and the protrusion is inserted into and coupled within the ball introducing hole.
3 more elements
A rack driven electric power steering apparatus comprising:
- a rack bar having an outer screw groove on an outer peripheral surface thereof;
- a ball nut having an inner screw groove corresponding to the outer screw groove of the rack bar on an inner peripheral surface thereof to be coupled to the rack bar by means of balls and having a ball circulating passage axially passing through the ball nut between an inner peripheral surface and an outer peripheral surface thereof;
- a pair of end caps each having a ball introducing passage, one side of which is communicated with the ball circulating passage and an opposite side of which is communicated with the outer screw groove of the rack bar and the inner screw groove of the ball nut, and coupled to opposite inner ends of the ball nut;
- and
- a pair of end cap rings coupled to outer sides of the end caps respectively to prevent separation of the balls,
- wherein each of the end caps includes a coupling unit on separated surfaces thereof so that the end cap is separated into two pieces along the ball introducing passage.
3 more elements
Dependencies are inferred from the claim text.