Nsk Corporation

Nsk Steering Systems Co., Ltd.

Toru Segawa

Kiyoshi Sadakata

Takahiro Minamigata

Takeshi Fujiwara

Toru Ishii

Osamu Tatewaki

Ryou Oosawa

Minao Umeda

Hiroshi Eda

Kazuo Chikaraishi

Takeshi Yamamoto

Nobuyuki Nishimura

Seiichi Moriyama

Hiroshi Shibazaki

Kazuhiko Kojima

Yoshifumi Kurokawa

Seiji Ueno

Masaru Wada

Souta Matsumoto

Ryota Sugihara

Yushi Momo

Takayoshi Kanazawa

Akihide Fujita

Ryo Osawa

Yuki Uchiyama

A torque transmission joint includes a first elastic body having a plurality of first elastic pieces pinched in a circumferential direction between respective first convex portions and a coupling, and a second elastic body having a plurality of second elastic pieces pinched in the circumferential direction between respective second convex portions and the coupling.

Torque transfer joint and electric motor with worm reduction gear

A torque transmission joint to suppress occurrence of noise when reversing the direction of rotation of a drive shaft. A first transmission member fixed to an output shaft (the drive shaft) is engaged with a first elastic member such that a first gap in a circumferential direction is interposed, as well as with an intermediate transmission member such that a larger gap in the circumferential direction is interposed. A second transmission member fixed to an end portion of a worm is engaged with a second elastic member such that a second gap in the circumferential direction is interposed, as well as with the intermediate transmission member such that a larger gap in the circumferential direction is interposed. First and second annular convex portions are fitted to, respectively, first and second concave portions to prevent separation of the first and second elastic members with respect to the intermediate transmission member.

Torque transmission joint and electric-powered power steering apparatus

The torque transmission joint includes an intermediate transmission member, and a first transmission member and a second transmission member that are arranged with one each on both side sections in the axial direction of the intermediate transmission member, with the outer side sections in the radial direction of each engaging with the inside section in the radial direction of the intermediate transmission member. The first transmission member and the second transmission member have a first preliminary engagement section and a second preliminary engagement section at the end sections in the axial direction on sides close to each other. The first preliminary engagement section and the second preliminary engagement section engage with each other with a circumferential gap interposed therebetween that does not disappear when torque transmission is performed between the first transmission member and the second transmission member via the intermediate transmission member.

Torque transmission joint and electric power steering device

A worm reducer includes: a housing including a wheel accommodating portion, and a worm accommodating portion; a worm wheel including wheel teeth disposed on an outer circumferential surface and rotatably supported inside the wheel accommodating portion; and a worm including worm teeth disposed on an outer circumferential surface to mesh with the wheel teeth and rotatably supported inside the worm accommodating portion, wherein a proximal end portion of the worm is connected to a drive shaft such that torque can be transmitted. An inner circumferential surface of the worm accommodating portion includes a housing side step surface which faces a proximal end side in an axial direction of the worm. An outer circumferential surface of the worm includes a worm side step surface which closely faces the housing side step surface in the axial direction at a portion axially deviated from a portion where the worm teeth are disposed.

Worm reducer

A worm reduction gear, including: an inner diameter side holder in which a bearing is internally fitted and held; an outer diameter side holder which includes a holder holding part in which the inner diameter side holder is internally fitted and held so as to be able to be relatively rotated and moved and to be displaced in a direction orthogonal to a center axis of a worm wheel and a center axis of a worm, and which is internally fitted and held in a holding recessed part of a housing; and an elastic urging member in a circumferential direction which elastically urges the inner diameter side holder against the outer diameter side holder in a direction of rotating in the circumferential direction.

Worm gear reducer

A driving-side concave-convex portion of a driving-side transmission member is engaged with an elastic member. The driving-side concave-convex portion is engaged with an intermediate concave-convex portion of an intermediate transmission member with a circumferential gap being interposed therebetween. A driven-side concave-convex portion of a driven-side transmission member is engaged with the elastic member. The driven-side concave-convex portion is engaged with the intermediate concave-convex portion with a circumferential gap being interposed therebetween. Both axial side surfaces and a periphery of the intermediate transmission member are covered by a side surface covering portion and a periphery covering portion of the elastic member.

A first concave-convex portion of a first transmission member is engaged with an intermediate concave-convex portion of an intermediate transmission member with a circumferential gap being therebetween. A second concave-convex portion of a second transmission member is engaged with the intermediate concave-convex portion with a circumferential gap being therebetween. A first elastic member and a second elastic member are engaged with a first engagement portion and a second engagement portion of the intermediate transmission member such that separation between the intermediate transmission member and the first elastic member and the second elastic member can be prevented.

There is provided a method of assembling a worm reducer, which includes causing a worm wheel to be rotatably supported in a wheel accommodation part, externally fitting a pair of bearings at tip-side and base-side positions of a worm, inserting the worm into a worm accommodation part from an opening side thereof at a state where the worm is offset outward in a radial direction of the worm wheel with respect to a center axis of the worm accommodation part, causing the bearing which is externally fitted to a leading side in an insertion direction of the worm to pass an outer diameter-side of a part of an outer peripheral edge of the worm wheel, which protrudes most into the worm accommodation part, causing the worm teeth to mesh with the worm wheel, and further inserting the worm to a predetermined position in the worm accommodation part.

Worm reducer and method of assembling worm reducer

A pair of wedge-shaped pieces are provided in an annular space that is defined between an inner circumferential surface of a holding recess portion and an outer circumferential surface of a bearing holder in two position that are symmetrical with each other with respect to a meshing portion between a worm wheel and worm teeth and an imaginary plane &#x3b1; that contains a center axis of a worm in such a way as to fill the annular space. Then, an elastic force is imparted to both the wedge-shaped pieces in a direction in which the pair of wedge-shaped pieces move away from the meshing portion in relation to a circumferential direction.

Worm reduction gear

A driving-side transmission portion of an output shaft of an electric motor and a driven-side transmission portion of a worm shaft are coupled to each other via a torque transmission joint including an elastic member and a coupling such that the torque can be transmitted. One axial end portion of a coupling-side concave-convex portion of the coupling is engaged with a first driving-side concave-convex portion of the driving-side transmission portion with a gap in the circumferential direction, and the other axial end portion thereof is engaged with a first driven-side concave-convex portion of the driven-side transmission portion with a gap in the circumferential direction. The elastic member is provided between an axial center portion of the coupling-side concave-convex portion, and a second driving-side concave-convex portion of the driving-side transmission portion and a second driven-side concave-convex portion of the driven-side transmission portion such that the torque can be transmitted respectively.

A slide member () is externally fitted to an outer peripheral surface of an outer ring () configuring a tip side bearing () for supporting a tip portion of a worm shaft () so as to be displaceable in an axial direction. A first inclined cylindrical face portion () which is an inclined surface disposed on an outer peripheral surface of the slide member (), and a second inclined cylindrical face portion () which is an inclined surface disposed on an inner peripheral surface of a guide member () internally fitted and fixed to a holding hole () of a housing () are fitted to each other so as to be slidable in an inclined direction of the respective inclined cylindrical face portions (). An elastic ring () which biases a bearing holding member () against to one side in the axial direction is disposed. This realizes a structure which can shorten an axial dimension of a tip side portion of the worm shaft in an electric power steering device including biasing means for minimizing backlash in a meshing portion of a worm reduction gear.

Electric power steering device

A torque transmission joint transmits torque between a drive shaft and a driven shaft. The torque transmission joint includes: a coupling including: a first concave-convex portion which is provided on one of inner and outer circumferential surfaces thereof and is engaged with a drive-side concave-convex portion of the drive shaft with a gap; and a second concave-convex portion which is provided on the other of the inner and outer circumferential surfaces and is engaged with a driven-side concave-convex portion of the driven shaft with a gap; a drive-side elastic member which is provided between the drive shaft and the coupling to be torque-transmittable; and a driven-side elastic member which is provided between the coupling and the driven shaft to be torque-transmittable. A concave-convex shape of the first concave-convex portion and a concave-convex shape of the second concave-convex portion are different from each other.

Torque transmission joint and electric power steering system

An electric power steering device includes a housing, a rotating shaft for steering, a worm wheel, a worm shaft, a tip side bearing, an electric motor, and biasing mechanism. The biasing mechanism includes a wedge piece and an elastic member for a wedge piece. The wedge piece is disposed between an outer circumferential surface of the tip side bearing and an inner circumferential surface of the housing in a state where the wedge piece in a circumferential direction is displaceable. The elastic member for a wedge piece applies elastic force toward one circumferential side to the wedge piece.

Electrically driven power steering device

A torque transmission joint has a shock-absorbing member between a drive shaft and a driven shaft. When the drive shaft is rotated in one direction, forces due to torque transmitted from the drive shaft to the driven shaft act inward in a radial direction of the shock-absorbing member on held sections that are held between one side surfaces in the circumferential direction of drive-side arm sections that are positioned in the front side in the one direction of rotation of the drive shaft, and side surfaces in the circumferential direction of driven-side arm sections that are positioned on the rear side in the one direction of rotation of the drive shaft.

Torque transmission joint and electric power steering apparatus

A shock-absorbing member comprises held sections located at a plurality of locations in a circumferential direction and comprising paired held sections and non-paired held sections, and is constructed to have a non-circular cylindrical shape in cross-section. Portions where outer-diameter side end sections of held sections that are adjacent to each other in the circumferential direction are made continuous by way of outer-diameter side cover sections, and portions where inner-diameter side end sections of held sections that are adjacent to each other in the circumferential direction are made continuous directly or by way of inner-diameter side cover sections, in an alternating sequence in the circumferential direction. Drive-side arm sections are placed between the non-paired held sections, driven-side arm sections are placed between the paired held sections, and the outer circumferential surfaces of the drive-side arm sections are covered by the outer-diameter side cover sections.

Growing community of inventors

Maebashi, Japan

Toru Segawa