JPH10115505A - Noncontact revolution angle sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variations in input/output characteristic of a sensor thereby improving product quality by setting a gap-adjusting means for changing a gap of a pair of opposite magnets. SOLUTION: A state of a relative positional relationship of a gap-setting member 44 is rotated in a clockwise direction to a magnet-fitting member 38 set securely at a leading end part of a rotary shaft 35. A pair of right and left magnets 41 are pressed outward by an outer circumferential face of an inner cylindrical part 44a to increase a gap, so that a magnetic field formed at the gap is reduced in size. When an output is large compared with a reference value, the setting member 44 is rotated in the clockwise direction to adjust a size of the magnetic field acting on a Hall device 46. If the output is small compared with the reference value, the setting member is rotated in a counterclockwise direction to adjust the size. At the time of the adjustment, the front end of a projection formed in a resin holder 40 is brought in contact with an inner circumferential face of an outer cylindrical part 44b thereby decreasing a rotational friction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact rotation angle sensor, and more particularly to a non-contact rotation angle sensor using an electromagnetic transducer such as a Hall element.

[0002]

2. Description of the Related Art The structure of a conventional non-contact type rotation angle sensor of this type will be described below with reference to Japanese Patent Application Laid-Open No. 2-122205. That is, in FIGS. 8 and 9, the sensor housing 1 is a resin cylindrical body having a gradually decreasing diameter from the upper end to the lower end, and the inner peripheral wall near the lower end protrudes inward to partition the inside of the cylinder up and down. It becomes a wall, and a pivot support opening 2 is provided at the center thereof. Further, a cylindrical signal connection portion 3 is formed so as to protrude from the side wall of the housing 1 at right angles.

A rotary shaft 4 is mounted through the shaft support opening 2 from below and has a tip 2a substantially reaching the center of the housing 1, and the tip 2a has a cross section having a U-shape. Character-shaped resin magnet holder 4a is arranged,
A pair of permanent magnets 5A and 5B, which are opposed to each other at an interval, is fixed to the magnet holder 4a by bonding, and an iron piece 6 is fixed in contact with the back of the permanent magnets. An oil seal 9 of the rotating shaft 4 is provided on the outer periphery of the lower end opening 8 of the housing 1 to maintain liquid tightness.

The upper end opening 10 of the housing 1 has a stepped inner periphery and a gradually reduced diameter, and is provided with a substrate holder 11 adhered and fixed to the stepped edge. A storage room 12 for magnets and the like is formed.
A central portion of the substrate holder 11 projects downward in a cylindrical shape to form an element holding portion 13, which is located between the pair of permanent magnets 5A and 5B.

A lead of a Hall element 15 extending upward is connected to a printed circuit board 14 adhered and fixed on the substrate holder 11 in the element holding section 13. The upper end opening 10 is covered with a cover body 16. The cover body 16 is liquid-tightly caulked around the outer periphery of the upper opening 10 via an O-ring 17 provided on the end face of the upper opening 10.

A hybrid IC terminal 18 extends from the printed circuit board 14 and is connected to one end of a housing terminal 19 embedded in the side wall surface of the housing 1 by soldering or the like, and the other end of the housing terminal 19 is provided. Protrudes into the signal connection portion 3 of the housing 1 and is connected to the signal line 21 of the signal cable C that penetrates the grommet 20.

In the detector having the above-described structure, the base end of the rotating shaft 4 is connected to an object to be measured by an appropriate means, and rotates according to the displacement angle. With this rotation, the pair of permanent magnets 5A and 5B rotate around the Hall element 15, the magnetic field direction changes, and the output of the Hall element 15 changes as shown in FIG. In this figure, the rotation axis 4 is shifted from -90 degrees to +
During the rotation to 90 degrees, the voltage at the output of the Hall element 15 continuously changes on a sine wave from -VA to + VA. Then, the output of the Hall element 15 is amplified by an amplifier circuit on the printed circuit board 14 and taken out by the signal line 21.

[0008]

However, in the non-contact type rotation angle sensor as described above, the Hall element 15 is required.
Because the distance between the pair of permanent magnets 5A and 5B sandwiching is fixed, the input / output characteristics of the Hall element vary, and the material, dimensions, magnetization amount, mounting position, and posture of the permanent magnet vary. There is a problem that large variations occur in the input / output characteristics.

The present invention has been made in view of the above problems, and has as its object to improve the quality by adjusting the distance between a pair of magnets to reduce variations in the input / output characteristics of the sensor. .

[0010]

According to a first aspect of the present invention, a non-contact rotation angle sensor is connected to a rotation shaft of an object to be measured.
At the tip of a rotating shaft that rotates with the rotation of the device to be measured, a pair of magnets are provided facing each other with the center line of the rotating shaft interposed therebetween, and the magnetic field space formed between the pair of magnets A non-contact rotation angle sensor fixed and arranged on the center line of the rotating shaft and provided with a magnetic detection element for detecting the magnitude of the magnetic field of the pair of magnets, wherein a facing distance between the pair of magnets is changed. A non-contact type rotation angle sensor, comprising:

According to a second aspect of the present invention, the space setting means is rotatably mounted on the rotary shaft, and has a ring-shaped groove having a constant width which sandwiches the magnet with a wall from a diameter direction. A cup member whose diameter gradually increases in the rotation direction, and a movement restricting member fixed to the rotation shaft to restrict movement of the pair of magnets in the rotation direction and to enable the magnets to move in the diameter direction. The non-contact rotation angle sensor according to claim 1, wherein:

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Embodiment 1 of the present invention will be described with reference to FIGS. In the figure, a housing 30 of the sensor is a resin cylindrical body having both ends opened, and an inner peripheral wall near the right end opening is integrally formed as a partition wall 32 protruding inward and partitioning the inside of the cylinder into right and left. 3
A through-hole 33 through which a rotating shaft 35 to be described later passes is formed in a central portion of 2, and a bearing is formed by the through-hole 33. A mounting flange 36 is formed to project at a right angle from the outer peripheral surface of the housing 30, and a signal connection portion X is formed at the left end opening.

A rotary shaft 35, one end of which is connected to the object to be measured by a connecting member 37, is rotatably supported by a bearing formed by the through hole 33, and is rotatably supported by the other end of the rotary shaft 35. A magnet mounting member 38 having a round dish shape and a concave central portion is fixedly attached to the other end of the rotary shaft 35 by a mounting hole 45 formed in the bottom of the central portion. At the same time, a flange 38a formed by projecting outward at a right angle from the periphery of the concave portion formed at the center thereof is formed flat over the entire circumference,
Further, plate-like guide members 42, 42 erected in parallel at symmetrical positions on the flange portion 38a around the rotation shaft 35.
Are arranged in a pair, and a pair of magnets 41, 41 whose three sides are held by a U-shaped resin holder 40 are arranged between the guide members 42, 42. Thereby, the movement direction of the pair of magnets 41, 41 is restricted only in the diameter direction.

Further, a spacing member 44 is rotatably attached to the other end of the rotating shaft 35 to which the magnet attachment member 38 is fixedly attached. As shown in FIGS. 2 (a) and 2 (b), the interval setting member 44 has an inner cylindrical portion 44a which is open at one end and a diameter larger than the inner cylindrical portion 44a. On the other hand, the opening of the outer cylindrical portion 44b, that is, the donut-shaped opening formed between the inner cylindrical portion 44a and the outer cylindrical portion 44b is open in the opposite direction. At the center of the bottom of the inner cylindrical portion 44a, a mounting hole 44f having a hole diameter larger than the hole diameter of the magnet mounting member 38 is formed, and the distal end portion 35a of the rotary shaft 35 is loosely fitted into the mounting hole 44f. The interval setting member 44 is rotatably attached to the distal end portion 35a.

The outer cylindrical portion 44b of the interval setting member 44
Are 0 to 180 degrees and 180 to 36 degrees.
Each becomes gradually smaller along the circumferential direction over a range of 0 degrees, and the outer peripheral surface of the cup-shaped inner cylindrical portion 44a is 0 degrees to
180 degrees and gradually increases along the circumferential direction over the range of 180 degrees to 360 degrees.
The distance between the inner peripheral surface 44bb of the outer cylindrical portion 44b and the outer peripheral surface 44aa of the outer cylindrical portion 44a is maintained at a constant L, and the inner peripheral surface of the outer cylindrical portion 44b and the outer peripheral surface of the inner cylindrical portion 44a are opposed to each other at two locations. A step 44e is provided at the position. That is, the relative positional relationship between the position of the maximum radius (minimum radius) of the inner peripheral surface of the outer cylinder portion 44b and the position of the maximum radius (minimum radius) of the outer peripheral surface of the inner cylinder portion 44a is set to match. ing.

As a result, the tip 35a of the rotating shaft 35
The space setting member 44 is rotated clockwise (rightward) from the state of the relative positional relationship of FIG. 6 to the state of the relative positional relationship of FIG. When rotated around, the pair of magnets 41 located on the left and right are pressed outward by the outer peripheral surface of the inner cylindrical portion 44a to increase the interval therebetween, and the magnitude of the magnetic field formed therebetween decreases. Therefore, when the output is larger than the reference value, 0 to 1 in the clockwise direction.
80 degree range (from one step 44e to the other step 44e
To adjust the magnitude of the magnetic field acting on the Hall element 46. When the output is smaller than the reference value, the rotation is adjusted in the range of 0 to 180 degrees in the counterclockwise direction. At the time of this adjustment, the resin holder 4
The tip of the ridge 40a provided on the outer cylinder portion 44 abuts on the inner peripheral surface of the outer cylindrical portion 44b to reduce rotational friction.

The outer cylindrical portion 44b is formed and arranged concentrically with the inner cylindrical portion 44a, and the opening edge of the inner cylindrical portion 44a and one opening edge of the outer cylindrical portion 44b are connected by a plate-like connecting portion 44c. A hall element 46 is arranged at the center of the space formed inside the inner cylindrical portion 44a in a non-contact state with the inner wall surface.

The lead terminals of the Hall element 46 are soldered to a printed board 71. The printed board 71 is sealed via a fixing boss 47 to hermetically seal the left end opening of the housing 30 in a watertight manner. The electric signal from the Hall element 46 is attached to the lid 48 and output to the outside via the lead wire 49. A molding agent 50 further reinforces the sealing lid 48 for sealing the opening of the housing 30 in a water-tight manner, and 51 is a liquid-tight seal between the periphery of the opening at the right end of the housing 30 and the outer periphery of the rotary shaft 35. An oil seal that holds and seals.

The above structure is assembled as shown in FIG. That is, the periphery of the mounting hole 45 formed in the concave portion of the magnet mounting member 38 is sandwiched by the pair of washers 60 and 61 between the tip 35 a of the rotating shaft 35, and then the magnet 41 is inserted into each of the pair of guide members 42. , 41 are sandwiched, and a gap setting member 44 is covered so as to cover them, and the mounting hole 44 f is rotatably fixed to the distal end portion 35 a of the rotating shaft 35. In this state, the electrical output at that time is checked while rotating the connecting member 37 by a predetermined amount. When the output is small, the interval setting member 44 is rotated counterclockwise to obtain the magnitude of the magnetic field applied to the Hall element 46. If the output is too large, the adjustment is made by rotating the output clockwise to reduce the magnitude of the magnetic field.

[0020]

As described above, according to the present invention, the output can be easily adjusted with a simple structure, and the effect that the mass productivity can be improved is exhibited.

[Brief description of the drawings]

FIG. 1 is a cross-sectional explanatory diagram for describing an overall outline of a first embodiment according to the present invention.

FIG. 2 is an exploded view of a main part according to the present invention.

FIG. 3 is a side view of a main part according to the present invention.

4 is an explanatory plan view of a magnet mounting member 38. FIG.

5 is an explanatory plan view of the interval setting member 44. FIG.

FIG. 6 is a state explanatory view for explaining the operation of the present invention.

7 is a state explanatory view for explaining the operation of the present invention (a state in which the interval setting member 44 in FIG. 6 is rotated clockwise).

FIG. 8 is an explanatory sectional view of a related art.

FIG. 9 is an explanatory sectional view taken along the line II-II of FIG. 8;

FIG. 10 is a characteristic explanatory diagram for explaining the conventional example of FIG. 8;

[Explanation of symbols]

 Reference Signs List 30 housing 32 partition wall 35 rotating shaft 37 connecting member 38 magnet mounting member 38a flange 40 resin holder 41 magnet 42 guide member 44 interval setting member 44a inner cylinder 44b outer cylinder 46 hole element 48 sealing element 49 lead wire 50 Molding agent 51 Oil seal 71 Printed circuit board

Claims (2)

[Claims] 1. A pair of magnets disposed opposite to each other at a tip of a rotating shaft of an object to be measured with a center line of the rotating shaft interposed therebetween, and a pair of magnets passing through a parallel magnetic field formed between the pair of magnets. A non-contact rotation angle sensor fixed and arranged on the center line of the rotating shaft and provided with a magnetic detection element for detecting the magnitude of the magnetic field of the pair of magnets, wherein a facing distance between the pair of magnets is changed. A non-contact type rotation angle sensor, comprising: 2. The space adjusting means is rotatably attached to the rotating shaft, and arc-shaped holding means for holding the magnet on a wall surface in a diametric direction is formed in line symmetry.
A first means set so that the diameter of the arc-shaped holding means gradually increases in the rotating direction; and a first means fixed to the rotating shaft to restrict the movement of the pair of magnets in the rotating direction. 2. A non-contact type rotation angle sensor according to claim 1, further comprising a movement restricting member which can move the rotation angle sensor in a diameter direction.