Valve unit
A valve unit includes a rotary valve having a predetermined clearance between an inner surface of a main body and a valve element. The magnet coupling includes eight outer peripheral magnets and eight inner peripheral magnets having N-poles and S-poles each on an outer or inner peripheral side. The outer peripheral magnets are disposed such that the N-poles and the S-poles are disposed alternately in a circumferential direction and such that a distance between the central axis and an outer peripheral surface of the outer peripheral magnets is between 90% and 100% of a distance between the central axis and an outer surface of the main body closest to the central axis in a direction perpendicular to the central axis. The inner peripheral magnets are disposed opposite to the outer peripheral magnets such that the N-poles and the S-poles are disposed alternately in the circumferential direction.
1 . A valve unit comprising:
a rotary valve comprising:
a main body comprising a cylindrical valve chamber; and
a valve element, housed in the valve chamber and rotatable about a central axis of the valve chamber, that controls flow of a fluid that flows into the valve chamber according to a rotational position of the valve element;
a motor comprising a rotary shaft that rotates and is held at a predetermined rotary position; and
a magnet coupling that transmits a torque between the rotary shaft and the valve element, wherein
the rotary valve has a predetermined clearance between an inner surface of the main body and the valve element,
the magnet coupling comprises:
eight outer peripheral magnets having N-poles and S-poles, wherein each of the N-poles and S-poles is disposed on an outer peripheral side or an inner peripheral side, and
eight inner peripheral magnets having N-poles and S-poles, wherein each of the N-poles and S-poles is disposed on an outer peripheral side or an inner peripheral side,
the outer peripheral magnets are disposed in a circle about the central axis such that the N-poles and the S-poles are disposed alternately in a circumferential direction and such that a distance between the central axis and an outer peripheral surface of the outer peripheral magnets is between 90% and 100% of a distance between the central axis and an outer surface of the main body closest to the central axis in a direction perpendicular to the central axis,
the inner peripheral magnets are disposed in a circle about the central axis and opposite to the outer peripheral magnets such that the N-poles and the S-poles are disposed alternately in the circumferential direction, and
the outer peripheral magnets and inner peripheral magnets are disposed such that the N-poles of the inner peripheral magnets are opposite to the S-poles of the outer peripheral magnets and the S-poles of the inner peripheral magnets are opposite to the N-poles of the outer peripheral magnets, respectively.
2 . The valve unit according to claim 1 , wherein the outer surface of the outer peripheral magnets closest to the outer surface of the main body is at a position within 5 mm apart from the outer surface of the main body closest to the central axis.
3 . The valve unit according to claim 1 , wherein
the main body has a regular quadrangular prism shape that extends in an extending direction of the central axis, and
the distance between the central axis and the outer surface of the main body closest to the central axis is 30 mm.
4 . The valve unit according to claim 3 , wherein a distance between the central axis and the outer peripheral surface of each of the outer peripheral magnets is 27.5 mm.
5 . The valve unit according to claim 4 , wherein a thickness of the outer peripheral magnets and a thickness of the inner peripheral magnets measured in a radial direction are 3 mm.
6 . The valve unit according to claim 1 , wherein the fluid is a liquid.
7 . The valve unit according to claim 1 , wherein the N-poles and the S-poles of the outer peripheral magnets and the N-poles and the S-poles of the inner peripheral magnets are disposed alternately in a radial direction from the central axis toward outside.
8 . A valve unit comprising:
a rotary valve comprising:
a main body comprising a cylindrical valve chamber; and
a valve element being housed in the valve chamber and having a predetermined clearance between an inner surface of the main body and the valve element, wherein
the valve element extends along a central axis of the valve chamber to rotate about the central axis of the valve chamber in a rotation angle range between +45° and −45° relative to a neutral position, and
the valve element includes:
a central portion in a columnar shape that has a central axis aligned with the central axis of the valve chamber; and
a first divider, a second divider, and a third divider that protrude from the central portion in a radial direction of the valve chamber and divide the valve chamber into regions, wherein each of the first divider, the second divider, and the third divider has a flat plate shape, wherein
the valve element is held at different rotation angles in the rotation angle range to hold the first divider, the second divider, and the third divider at different positions to control flow of a fluid that flows into the valve chamber;
a motor comprising a rotary shaft that rotates about the central axis of the valve chamber, wherein the rotary shaft is held at rotation positions to hold the valve element at rotation angles in the rotation angle range; and
a magnet coupling that is disposed between the rotary valve and the motor to transmit a torque between the rotary shaft and the valve element without contact, wherein
the rotary valve has a predetermined clearance between an inner surface of the main body and the valve element,
the magnet coupling comprises:
an outer peripheral component in a cylindrical shape with a closed bottom that is coupled to an end of the rotary shaft to rotate with the rotary shaft, wherein the outer peripheral component is separated from the main body;
an inner peripheral component in a round shape with a diameter less than an inner diameter of the outer peripheral component, wherein the inner peripheral component is disposed inside the outer peripheral component without contact and is coupled to an end of the central portion of the valve element;
four first outer peripheral magnets, each of which includes an N-pole on an outer peripheral side and an S-pole on an inner peripheral side;
four second outer peripheral magnets, each of which includes an N-pole on the inner peripheral side and an S-pole on the outer peripheral side;
four first inner peripheral magnets, each of which includes an N-pole on an outer peripheral side and an S-pole on an inner peripheral side; and
four second inner peripheral magnets, each of which includes an N-pole on the inner peripheral side and an S-pole on the outer peripheral side,
the first outer peripheral magnets and the second outer peripheral magnets are alternately disposed on an inner periphery of the outer peripheral component,
the first inner peripheral magnets and the second inner peripheral magnets are alternately disposed on the outer periphery of the inner peripheral component,
the first inner peripheral magnets are opposite to the first outer peripheral magnets in the radial direction of the valve chamber, and
the second inner peripheral magnets are opposite to the second outer peripheral magnets in the radial direction of the valve chamber.