Ntn Corporation

Panasonic Corporation

Shoji Itomi

Masahiro Kurita

Yuji Okamoto

Masahiko Kataoka

Kenichi Ichikawa

Norio Umezawa

Kouichirou Tsuruoka

A one-way clutch includes a C-shaped spring having one end thereof engaged by the inner ring and the other end abutting a roller at one end of a row of rollers that abut each other, thereby engaging the rollers with the outer ring and the inner ring. The inner ring has a radius at the engaging end of the cam surface opposed to the roller at the other end of the row of the rollers larger than its radii at the engaging ends of the cam surfaces opposed to the other rollers of the same row.

One-way clutch and reverse input preventive clutch

In a locking type reverse input blocking clutch, smooth finished surfaces having no directionality are formed, by barrel polishing, on surfaces brought into contact with rollers while rotation is being transmitted from the input side to the output side, i.e. an inner peripheral cylindrical surface of an outer ring and a surface of a lid portion opposed to the rollers. With this arrangement, it is possible to reduce the sliding resistance between the rollers and the outer ring and between the rollers and the lid portion, without the need to reduce the forces of springs for pushing the rollers into narrow portions of wedge-shaped spaces. This in turn makes it possible to reduce the torque necessary to transmit rotation from the input side to the output side, while maintaining high locking performance.

Reverse input blocking clutch

A torque sensor unit includes two magnetic angle sensors capable of detecting absolute rotation angles of a shaft member which indicate a twist angle of the shaft member when the shaft member is twisted. The shaft member has two end portions exposed to outside so that the shaft member can be connected at the two end portions to shaft-forming parts of a device.

Torque sensor unit

Clutch retainer

An angle detection error is prevented by using a columnar permanent magnet that is radially double-pole-magnetized as a rotating angle detecting sensor while preventing a gap between a plurality of magnetic sensors and an end face of the permanent magnet from being narrowed. The permanent magnet is a ferrite magnet or an alnico magnet having a diameter of 4 mm to 20 mm, and an axial length of 3 mm to 5 mm. The plurality of magnetic sensors detects radial magnetic flux densities at positions axially spaced 0.5 mm to 3.0 mm apart from a central portion of the permanent magnet, the central portion having a diameter equal to or smaller than 20% of the magnet diameter to make it possible to perform detection in a range in which a distribution curve of a radial magnetic flux density has a moderate inclination.

Rotating angle detecting sensor

A shaft and rolling bearings are mounted in the housing. A magnetic sensor is fixed to a first end surface of a shaft. A circuit board carrying a magnetic sensor is fixed to a surface of a lid of the housing at the second end. As a calibration voltage feed line, a cable is connected to the circuit board and extends outside through a hole formed through the lid. With the lid fixed in position, thereby applying a preload to rolling bearings, calibration voltage is supplied to the magnetic sensor through the calibration voltage feed line, thereby writing initial calibration parameters into the magnetic sensor from an external calibration device. After writing the parameters, the calibration voltage feed line is connected, at the outside, to a stabilizing output end of a power source input/output board fixed to the surface of the lid at the first end.

Rotation angle detecting unit

In a sensor of a sensor unit in which working voltage or calibration voltage is supplied through a single input end, working voltage can be stably supplied to the sensor after initial calibration. The sensor unit includes a voltage stabilizing circuit for stabilizing a voltage value of a supply power source to said working voltage, and a wiring for supplying said calibration voltage to the sensor, which are provided parallel to each other between the input end of the sensor and a power source connecting end for the sensor on the circuit board, and a switching portion which can disconnect the wiring, wherein an access hole is formed in the housing through which the switching portion is accessible to disconnect the wiring.

Sensor unit

In a rotation sensor unit, a lidis pressed against a housingto push an outer raceof a rolling bearing, thereby applying a preload to the bearingand increasing the rigidity of the bearing, so as to prevent run-out of a shaft. An encoderis supported on this shaft, and a magnetic sensor elementis supported on the lid, which is pressed against the housing. Thus, it is possible to prevent displacement of the magnetic sensor elementand the encoderrelative to each other. The shaft, lidand outer race, etc. are made of a soft magnetic material to define a magnetically shielded space between one axial end surface of the shaftand the lid, with the magnetic sensor elementmounted in the magnetically shielded space.

Rotation sensor unit

A one-way clutch unit includes a one-way clutch and an unlocking member. The one-way clutch includes inner and outer races. Two pockets having wedge spaces having a wedge angle are formed between the inner and outer races. Several rolling elements are received in each pocket. The unlocking member includes an annular portion concentric with the inner race, and axially extending unlocking pieces each received in one of the pockets between the end of the pocket that faces the narrow ends of the wedge spaces having the wedge angle and the rolling elements. By externally actuating the unlocking member, the rolling elements are moved toward the wide ends of the respective wedge space having the wedge angle, thereby unlocking the clutch. Thus, it is possible to unlock the clutch and prevent transmission of torque to the output member while the input member is rotating in the forward direction.

One-way clutch unit

A rotation sensor unit includes an encoder, a holder radially positioning the encoder, and a rolling bearing having an inner race. The rolling bearing is fitted around the shaft so that one end of the inner diameter surface of the inner race protrudes from the end of the outer diameter surface of the shaft. The holder has a screwed portion fitted in the inner race, positioning the encoder coaxially with the shaft. The holder is non-magnetic, having a retaining portion in which the encoder is axially pressed. The encoder is a plastic magnet, with protrusions and recesses formed integrally on its outer diameter surface and biting the inner diameter surface of the retaining portion to prevent the encoder from rotating. With the holder screwed to the shaft, the encoder is disposed between the magnetism detection element and the one end of the shaft.

An anti-reverse input clutch is provided which includes an output member including an output shaft held so as to be rotatable about the axis of an input member, and a cam member which is a separate member from the output shaft and on which cam surfaces are formed. The cam member is rotationally fixed to the output shaft. Thus, each of the output shaft and the cam shaft can be easily formed, so that it is possible to significantly reduce the time and cost for manufacturing the output member and improve the freedom of design thereof.

Anti-reverse input clutch

A rotational angle detecting sensor has a cylindrical housing including an end wall at a first end thereof. A covering member covers the second open end of the housing. A rotary shaft extends through the end wall of the housing and includes a large-diameter portion having a shoulder surface and rotatably received in the housing. A rotational angle detector is disposed between the inner surface of the covering member and the end surface of the large-diameter portion of the rotary shaft. An actuate groove is formed in the inner surface of the end wall of the housing concentrically with the rotary shaft. A stopper pin is attached to the shoulder surface of the large-diameter portion of the rotary shaft so as to be movable in the groove. The stopper pin abuts against the circumferential ends of the groove, thereby limiting the rotational range of the stopper pin.

Rotational angle detecting sensor

An oil condition sensor is proposed which can accurately determine the degree to which oil is contaminated with metallic powder. It includes a permanent magnet and a sensor head provided around the permanent magnet. The sensor head includes a cup-shaped electrode and a plurality of rod-shaped conductors that are axially spaced from the cup-shaped electrode. The conductors are connected to a power supply through separate resistors. When the amount of metallic powder in the oil increases, a greater number of conductors are electrically connected to the cup-shaped electrode. Thus, by finding the number of conductors electrically connected to the cup-shaped electrode, it is possible to determine the degree to which the oil is contaminated with metallic powder. Since the resistors need not be immersed in the oil, their specific resistivities will scarcely change, so that the degree of contamination of the oil can be determined with high accuracy.

Oil condition sensor

An oil condition sensor includes rod-shaped electrodes and an opposed cup-shaped electrode. The rod-shaped electrodes are connected to a first power supply through first fixed resistors having a predetermined threshold. The voltage from the first power supply is applied through the respective rod-shaped electrodes to first inputs of respective operational amplifiers. The sensor further includes a second power supply which produces a voltage applied to second inputs of the respective operational amplifiers. Each operational amplifier produces a predetermined voltage if the voltage applied to the first input falls below the voltage applied to the second input. The output of each operational amplifier is connected to the second input through a second fixed resistor. There is a hysteresis relation between the input and output of the amplifiers, so that once an operational amplifier produces voltage, even if voltage from the corresponding conductor falls thereafter, the operational amplifier continuously produces voltage.

Growing community of inventors

Kuwana, Japan

Shoji Itomi