A rotary encoder (1) is provided, including a shaft (W) connected to and drivable by an external shaft, a first gear unit (G1) and a second gear unit (G2), each following rotations of the shaft (W). Both gear units (G1, G2) (G1 and G2) are drivable independently of one another by the shaft (W), a first gear stage (G1S1) of the first gear unit (G1) has a first detection unit (E1), and a gear stage (G2S2) downstream of a first gear stage (G2S1) of the second gear unit (G2) has a second detection unit (E2). An evaluation unit derives the angular position from signals of the detection units (E1, E2) and compares the rotations of the first gear stage (G1S1) and the downstream gear stage (G2S2) for plausibility, taking into account a known ratio of the rotation of the first gear stage (G1S1) to the rotation of the downstream gear stage (G2S2).

An inductive gear sensing system suitable for sensing gear (gear tooth) movement, such as some combination of speed, direction and position, based on differential sensor response waveforms. Example embodiments of inductive gear sensing with differential sensor response for different gear configurations include generating differential pulsed/phased sensor response signals from dual differential sensors based on axial (proximity-type) sensing for offset differential sensors (FIG. 1B, 102, 102; FIG. 2B, 201, 202), and generating asymmetrical response signals from a single sensor based on lateral and axial sensing with either asymmetrical gear teeth (FIG. 3A, 30A; FIG. 3B, 30B) or an asymmetrical sensor (FIG. 4B, 401) or a combination of both.

The invention relates to a sensor system (1), and a method for determining an absolute rotation angle (δ) of a shaft (10) with a rotation angle range of more than one revolution and to a vehicle fitted with a sensor system (1), wherein the sensor system (1) has a main rotor (2) that can be connected rotationally synchronously to the shaft (10), a first auxiliary rotor (3) which is mechanically coupled to the main rotor (2), a second auxiliary rotor (4) mechanically coupled to the main rotor (2), a first sensor device (SE1) which is assigned to the first auxiliary rotor (3) for generating a first sensor signal dependent on a rotation angle of the first auxiliary rotor (3), a second sensor device (SE2) which is assigned to the second auxiliary rotor (4) for generating a second sensor signal dependent on a rotation angle of the second auxiliary rotor (4), a third sensor device (SE3) which is assigned to the main rotor (2) and which is used for generating a third sensor signal dependent on a relative rotation angle (γ) of the main rotor (2) and an evaluation device for determining the absolute rotation angle (δ) of the main rotor (2) from the sensor signals of the sensor devices (SE1, SE2, SE3). The detection range (α) of the third sensor device is less than 360°.

A sensor device includes a main driving gear, driven gears, an biasing member configured to bias the driven gears toward the main driving gear, a support member configured to support the biasing member, and a sensor configured to generate an electrical signal based on rotation of the driven gears. In a force applied when the biasing member biases the driven gears, assuming that a direction orthogonal to a tangent line at a point of action of the force is set as a first direction, the first direction is different from a second direction.

An absolute encoder suitable for size reduction is provided.

An absolute encoder includes: a first driving gear configured to rotate according to rotation of a spindle; a first driven gear having a center axis perpendicular to a center axis of the first driving gear and configured to engage with the first driving gear; and a second driving gear provided coaxially with the first driven gear and configured to rotate according to rotation of the first driven gear. The absolute encoder includes a permanent magnet (8) provided on a layshaft gear (5A) having a center axis perpendicular to the center axis of the first driven gear and where a worm wheel portion (52e) is formed to engage with the second driven gear; and a resin sheet (5A1) provided on the layshaft gear (5A) to prevent the permanent magnet (8) from coming out from the layshaft gear (5A) in the axial direction.

The present invention provides an absolute encoder suitable for reduction in thickness. An absolute encoder, for determining a rotation amount of a main spindle that rotates a plurality of revolutions, includes a first drive gear configured to rotate in accordance with rotation of the main spindle; a first driven gear that engages with the first drive gear; a second drive gear configured to rotate in accordance with rotation of the first driven gear; a second driven gear that engages with the second drive gear; and an angular sensor configured to detect a rotation angle at which a second rotating body is rotated in accordance with rotation of the second driven gear.

An absolute encoder suitable for size reduction is provided.

The absolute encoder includes a spindle gear (1A) fixed to a motor shaft (201), a permanent magnet (9) provided on the spindle gear (1A), and a first driven gear having a center axis perpendicular to a center axis of a worm gear portion (181), and engaging the wo m gear portion (181). The absolute encoder includes a second driving gear provided coaxially with the first driven gear and rotating according to a rotation of the first driven gear, and a second driven gear having a center axis perpendicular to the center axis of the first driven gear, and engaging the second driven gear. The spindle gear (1A) includes a magnet holder (170) which is fit onto a tip end of the motor shaft (201), coaxially with the motor shaft (201), and a resin gear portion (180) provided with the worm gear portion (181) on an outer side in a radial direction.

An absolute encoder preferable in being made compact is provided.

The absolute encoder includes a worm gear (101c) that rotates in accordance with rotation of a main spindle, and a worm wheel (102a) of which a central axis is perpendicular to a central axis of the worm gear (101c), the worm wheel engaging with the worm gear (101c). The worm gear (101c) is formed using a first material, and the worm wheel (102a) is formed using a second material different from the first material.

An absolute encoder preferable in being made compact is provided.

The absolute encoder includes a first drive gear, a first permanent magnet, a first angle sensor, and a first driven gear of a central axis that is perpendicular to a central axis of the first drive gear, the first driven gear engaging with the first drive gear. The absolute encoder includes a second drive gear coaxially provided with the first driven gear, the second drive gear being configured to rotate in accordance with rotation of the first driven gear. The absolute encoder includes a second driven gear of which a central axis is perpendicular to the central axis of the first driven gear, the second driven gear engaging with the second drive gear. The absolute encoder includes a second permanent magnet provided on a top end side of the second driven gear. The absolute encoder includes a second angle sensor configured to detect a rotation angle of the second driven gear, in accordance with a change in magnetic flux generated from the second permanent magnet. A reduction ratio between the first drive gear (worm gear (101c)) and the first driven gear (worm wheel (102a)) is set to a value for mitigating an effect of backlash between the first drive gear and the first driven gear, the backlash resulting in an error in the rotation angle of the second driven gear.

An absolute encoder preferable in being made compact is provided.

The absolute encoder includes a worm gear, a permanent magnet (19) provided on a top end side of the worm gear, and magnetic sensors. In the permanent magnet (19), a given first polar portion (N) among first polar portions each having a first polarity and a given second polar portion (S) among second polar portions each having a second polarity different from the first polarity are formed adjacent to each other, when viewed from an end surface of the permanent magnet (19) in an axial direction thereof. A given first polar portion (N) and a given second polar portion (S) are formed to be adjacent in a radial direction, with a radial middle portion of the permanent magnet (19) that is a boundary. A given first polar portion (N) and a given second polar portion (S) are formed to be adjacent in an axial direction, with an axial middle portion of the permanent magnet (19) that is a boundary.