Ntn Corporation

Koji Akiyoshi

Takahide Saito

Koji Sato

Naotsugu Kitayama

Isao Hori

Takayuki Norimatsu

Kenro Adachi

Kenichiro Itoh

Katsuhisa Suzuki

Masafumi Nakakoji

Takanobu Sato

Masahiro Kawai

Tomoaki Makino

Kenichiro Ito

Kyohei Sasanuma

Katsumi Furutani

Satoshi Utsunomiya

Marina Fukunari

Masako Ashimori

A rotation transmission device is configured such that when an electromagnet of an electromagnetic clutch is energized, an armature is attracted toward a rotor, so that a control retainer defining a two-way clutch is moved in an axial direction, whereby the control retainer and a rotary retainer are rotated relative to each other in a direction in which circumferential widths of pockets decrease, thereby disengaging pairs of rollers from an inner periphery of an outer ring and an outer periphery of an inner ring. The rotation transmission device includes a shock absorbing member on a surface of the armature facing the rotor, the shock absorbing member being configured to absorb impact force when the armature is attracted to the rotor by being elastically deformed.

Rotation transmission device

When a control retainer and a rotary retainer rotate relative to each other, a plurality of pairs of rollers received in respective pockets are pushed by pillars so as to move to their disengaged position. An anti-rotation arrangement is provided between an outer ring and the control retainer. The anti-rotation arrangement prevents the control retainer from rotating relative to the outer ring when the rollers are engaged, so that that the rollers does not move to their neutral position. This increases reliability. The anti-rotation arrangement includes a plurality of first protrusions formed on the surface of the outer ring, and a plurality of second protrusions formed on the surface of the control retainer axially opposed to the surface of the outer ring. Heat treatment is performed to the first and second protrusions so as to increase the hardness thereof.

A rotation transmission device includes a two-way clutch which is selectively engaged and disengaged by an electromagnetic clutch. The two-way clutch includes a control retainer and a rotary retainer. The control retainer and the rotary retainer have flanges and bars formed on outer peripheral portions of the respective flanges and arranged so as to circumferentially alternate with each other with pockets defined between adjacent bars. Two rollers are received in each pocket. When the control retainer and the rotary retainer are rotated relative to each other, the rollers are adapted to be pushed by the bars to the disengaged position. An anti-rotation arrangement is provided on opposed surfaces of an outer ring and the control retainer member. The anti-rotation arrangement is adapted to prevent the control retainer from rotating relative to the outer ring while the rollers are in engagement, thereby preventing the rollers from moving to the neutral position.

A rotation transmission device is configured such that when an electromagnet of an electromagnetic clutch is energized, a control retainer of a two-way clutch is moved in the axial direction, so that the control retainer and a rotary retainer rotate relative to each other in the direction in which the circumferential widths of pockets decrease, thereby disengaging pairs of rollers from an outer ring and an inner ring. A spring holder is provided which is fixed to an input shaft and kept in abutment with an axial end surface of the inner ring to prevent relative rotation between the control retainer and the rotary retainer in the direction in which the circumferential widths of the pockets decrease, from the neutral position of the rollers. The spring holder is prevented from axial movement to prevent untimely engagement of the two-way clutch. The inner ring is integral with the input shaft.

A rotation transmission device includes a control retainer and a rotary retainer having bars arranged circumferentially alternating with each other such that pockets are defined between the adjacent pairs of bars. A pair of rollers are mounted in each pocket with an elastic member disposed between the pair of rollers such that the pair of rollers are pushed by the respective bars to their respective disengaged positions when the control retainer and the rotary retainer rotate relative to each other. A spring holder is fitted on an input shaft while abutting one axial end surface of an inner ring. The spring holder has spring support pieces on the outer periphery thereof to prevent radially outward movement of the elastic members. The spring support pieces are plate-shaped members disposed radially outwardly of the elastic members to extend in the axial direction in parallel to the outer periphery of the inner ring.

A speed reducer includes an internal gear, an input shaft coaxial with the internal gear, and an eccentric disk on the input shaft and rotatable inside the internal gear. A cage, at an end of an output shaft, coaxial with the input shaft, and rotatable between the internal gear and the eccentric disk has pockets fewer in number than the internal gear's internal teeth. Rollers are received in the respective pockets such that when the input shaft rotates once, the rollers circumferentially move by a distance equal to one internal tooth width, causing the output shaft to be rotated at a reduced speed. The root radius of the internal gear, the radius of the circumcircle of the rolling bearing, and the outer diameter of the rollers are determined such that roller gaps defined between the rollers and the tooth bottoms of the internal gear are controlled to reduce vibration.

Speed reducer

A rotation transmission device includes a two-way clutch and an electromagnetic clutch for engaging and disengaging the two-way clutch and which can be easily assembled without the need for a shim to prevent movements of the clutches. The two-way clutch () and the electromagnetic clutch () are mounted in a housing () including at one end a positioning arrangement (). The two-way clutch () and the electromagnetic clutch () are biased by an elastic member () supported by the positioning arrangement () toward an anti-separation ring () provided on the inner periphery of the housing () at the other end thereof, and are thus prevented from moving.

A rotation transmission device includes an outer ring having an inner cylindrical surface, and an inner ring having outer cam surfaces. A pair of rollers and an elastic member biasing the rollers away from each other are mounted between the cylindrical surface and each adjacent pair of the cam surfaces. The rollers and the elastic members are retained by a control retainer and a rotary retainer each having a flange and crossbars extending from the flange and circumferentially alternating with the crossbars of the other retainer. The respective opposed pairs of rollers are pushed by the respective crossbars to a disengaged position when the retainers rotate relative to each other. The crossbars of the retainers are disposed between the outer ring and the inner ring and the flanges are provided outside the outer ring to minimize the axial length of the outer ring.

A speed reducer having rollers axially longer than its cage, includes coaxial input and output shafts with mutualy facing ends covered by a housing that supports an internal gear. An eccentric disk is mounted on an end of the input shaft to be located radially inwardly of, and rotatable relative to, the internal gear. A cage at the end of the output shaft is between the internal gear and a bearing fitted on the disk. The cage has pockets unequal in number to internal teeth of the internal gear. A roller in each pocket is rollable along the radially outer surface of the bearing outer race. The input shaft rotation is transmitted to the shaft at a reduced speed ratio determined by the number of the internal teeth. An annular recess is formed along the corner between the closed end and radially inner surfaces of the cage.

A rotation transmission device includes an outer ring having an inner periphery and an inner ring mounted inside the outer ring and having an outer periphery. A control retainer and a rotary retainer are disposed between opposed surfaces of the outer ring and the inner ring, and each of the retainers has a flange and bridges provided at the radially outer side of the respective flange and arranged circumferentially alternately with the bridges of the other retainer thereby defining pockets between the adjacent bridges. The control retainer is axially slidably and rotatably supported and the rotary retainer is axially immovably and rotatably supported. An electromagnetic clutch is mounted on a torque transmission shaft and includes an electromagnet having an electromagnetic coil, the electromagnetic clutch being configured to axially move the control retainer when the electromagnetic coil is energized and deenergized.

A one-way roller clutch includes an outer ring, and an inner ring mounted inside the outer ring and having an outer cylindrical surface. The outer ring has on its inner periphery a plurality of cam surfaces each defining a wedge-shaped space in cooperation with the cylindrical surface of the inner ring. Rollers are each mounted between one of the cam surfaces and the cylindrical surface. Each roller is biased by a coil spring toward a narrow portion of the corresponding wedge-shaped space. Each coil spring has at its end facing the roller a radially outwardly extending spiral roller abutment portion. The roller abutment portion prevents the end of the coil spring from slipping along and separating from the roller, thus stabilizing the attitude of the coil spring.

One-way clutch

A spring clutch is provided for which durability is improved by preventing a clutch spring from breaking due to fatigue. A cylindrical clutch spring made from a wire having a square section is mounted between a pulley and a pulley hub mounted in the pulley. An end of the clutch spring is coupled to the pulley hub. A clutch surface is formed on the inner periphery of the pulley and is formed with a large-diameter recess at a position opposite to the end portion of the clutch spring including the torque transmission end. When the pulley rotates in one direction, the clutch spring expands. At this time, the end portion of the clutch spring including the torque transmission end expands in the large-diameter recess, thus relaxing sharp torque produced in the clutch. This prevents local stress concentration on the clutch spring and breakage of the clutch spring and improves the durability of the clutch.

Spring clutch

A rotation transmission device which can quickly change the direction of rotation includes an inner ring having cam surfaces on its outer periphery, an outer ring having a cylindrical surface on its inner periphery, and pairs of circumferentially opposed rollers, the rollers of each pair being disposed between one of the cam surfaces and the cylindrical surface to be circumferentially opposed to each other. A roller separation spring is disposed between the rollers of each pair of rollers to bias the rollers away from each other so that the rollers are wedged between the cam surface and the cylindrical surface. The rollers are retained by a roller retainer which can change the distance between the rollers of each pair of rollers. By reducing the distance between the rollers of each pair of rollers with the roller retainer, the rollers can be disengaged from the cam surfaces and the cylindrical surface.

A power transmission changeover device for an automatic-transmission, four-wheel drive vehicle which can prevent rattling of gears while the gear position of the sub-transmission is being changed over. Air pipes extending from a negative pressure source for actuating an actuator for changing over gears of a sub-transmission, and electromagnetic valves have inner diameters of 4 mm or over. An accumulator is provided between the electromagnetic valves in the air pipes and the negative pressure source. This makes it possible to increase the operating speed and operating force of the actuator and, to shorten the duration of the neutral position when gears are changed over, and to increase the meshing force with new gears. It is thus possible to prevent rattling of gears due to improper meshing of gears.

Power transmission changeover devices for four-wheel drive vehicles

A hub clutch assembly is designed so that fluid pressure is used only while the driving mode is being changed over between a four-wheel drive position and a two-wheel drive position, while eliminating the necessity of holding a coupling member in position once the driving mode has been changed over. A driven member and a driving member are coupled together and uncoupled from each other by a slider which is moved under a negative or positive air pressure. A spring is used to maintain the slider in the two-wheel drive position, while a magnet is used to maintain the slider in the four-wheel drive position.

Growing community of inventors

Iwata, Japan

Koji Akiyoshi