JP3422337B2 - Weak current holding type solenoid - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a weak current holding type solenoid, and more particularly to an improvement of a weak current holding type solenoid attached to a flush water passage opening / closing valve of an automatic faucet, an automatic toilet bowl cleaning device or the like. Is.

[0002]

2. Description of the Related Art This type of weak current holding solenoid is
Annular coil, cylindrical plunger guide, cylindrical plunger, coil spring, pole core, valve seat packing,
And a yoke. The valve seat packing is in pressure contact with a diaphragm unit used as a flush water flow passage opening / closing valve of an automatic faucet, an automatic toilet flushing device, etc., and is provided at the end of the plunger.

Each of the above-mentioned members such as the yoke, the plunger, and the pole core is made of an inexpensive magnetic material such as iron.

An air gap is formed between the pole core and the plunger, or the formed air gap disappears.

In the weak current holding solenoid having the above structure, when the air gap disappears, a relatively large first current is applied to the coil when the suction operation rises. The attraction state of the plunger caused by the energization of the first current is a weak second state different from the first current.
Is retained while the coil is being energized, and is eliminated by stopping energization of the second current.

[0006]

By the way, in the conventional weak current holding type solenoid having the above-mentioned structure, the value of the second current is the residual magnetism or anti-attraction generated by passing the first current through the coil. It is determined by the spring force of the coil spring biased in the direction. Therefore, in order to reduce the value of the second current to reduce power consumption, it is necessary to reduce the spring force.

However, since the magnitude of the spring force is determined by the magnitude of the residual magnetism described above, if the residual magnetism cannot be reduced eventually, the value of the second current cannot be reduced. Can not.

Therefore, in order to reduce the residual magnetism generated by the first current, a yoke, a plunger, etc. are formed using a magnetic material having a high magnetic permeability (that is, a sharp rise in hysteresis) and a small residual magnetism. However, there is a problem in that the magnetic material as described above is expensive and thus increases the cost of the product.

Therefore, an object of the present invention is to provide a residual magnetism generated at the start of the suction operation of the plunger even if the yoke and the plunger, which are members for forming the magnetic circuit, are made of a relatively inexpensive magnetic material such as iron. To provide a weak current-holding solenoid capable of reducing the energization amount while holding the attracted state, as in the case where the above member is made of a high-cost magnetic material having a small residual magnetism. It is in.

[0010]

A weak current-holding solenoid according to the present invention includes a plunger biased in one direction in a magnetic circuit of an electromagnet to attract the plunger to the electromagnet in a direction opposite to the bias. The plunger is held at the suction completion position by the energization of the drive current and the subsequent energization of a current smaller than the above-mentioned drive current.The plunger has a low magnetic permeability lower than that of other parts. The position of the low magnetic permeability portion in the plunger having a portion is a position included in the magnetic circuit that contributes to holding and suction at least when the plunger is in the suction completion position, and the magnetic efficiency during suction is It is selected at a position where the residual magnetism can be reduced by decreasing.

[0011]

According to the above structure, the low magnetic permeability portion of the plunger due to the supply of the driving current to the electromagnet is at least included in the magnetic circuit that contributes to holding and attracting the plunger. The reduced efficiency reaches a position where the remanence can be reduced. Therefore, the residual magnetism generated by the energization of the drive current is narrowed down in the low magnetic permeability portion. Therefore, even if the member on which the magnetic circuit is formed is made of a relatively inexpensive magnetic material such as iron, it is possible to reduce the residual magnetism generated at the start of the suction operation of the plunger.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a view showing a weak current holding type solenoid according to an embodiment of the present invention.

The weak current holding solenoid is equipped with an annular coil 1, a cylindrical plunger guide 3, a cylindrical plunger 5, a coil spring 7, a pole core 9, a valve seat packing 11 and a yoke 13. For example, an automatic faucet, It is attached to a valve body 19 of a diaphragm used as an opening / closing valve for flushing water in an automatic toilet flushing device. The valve body 19 includes a diaphragm pressing member 15 and a diaphragm unit 17.

The yoke 13 is a frame body made of a relatively inexpensive magnetic material such as iron so as to have a square cross section as shown in the drawing. A circular plate (through hole) 22 is formed in a substantially central portion of a rectangular flat plate located at the bottom shown in FIG. 1, and a plurality of bolt mounting holes are formed in the peripheral portion of the flat plate. There is. Fastening members such as bolts 21 are inserted into the bolt mounting holes for mounting and fixing the weak current holding solenoid to the valve body 19 (see FIG. 2).

Further, the yoke 13 presses and fixes the diaphragm pressing member 15 and the diaphragm unit 17 together with the valve body 19 from the bottom thereof with bolts 21 to prevent water leakage in the water flow passage. On the yoke 13,
A magnetic circuit is formed by supplying an exciting current (a first current and a second current, which will be described later) from the power supply to the coil 1 through the wiring indicated by reference numeral 27 in FIG.

The cylindrical plunger guide 3 is made of a non-magnetic metal material, and a portion near one end portion (lower end portion in FIG. 1) of the cylindrical plunger guide 3 is fitted and inserted into the circular hole (through hole) 22 of the yoke 13. It is provided in the through space 2 of the annular coil 1 in the closed state. As a result, the lower end portion of the plunger guide 3 shown in FIG.
5 is opposed to the step portion projecting in the inner circumferential direction of the flange portion included in 5. An O-ring 23 (see also FIG. 2) is interposed in a gap formed by the outer peripheral side of the lower end of the plunger guide 3 and the step of the diaphragm pressing member 15.

A cylindrical pole core 9 made of a relatively inexpensive magnetic material such as iron is inserted into a portion of the plunger guide 3 near the other end (upper end in FIG. 1) of the through space 4. An O-ring 25 is provided on the outer peripheral portion of the pole core 9. This pole core 9 is shown in FIG.
As shown in FIG. 1, the plunger 5 is formed in a convex shape in cross section, and is inserted into the cavity 6 of the plunger 5 provided in the through space 4 of the plunger guide 3 together with the pole core 9, and the plunger 5 is shown in FIG. One end of a coil spring 7 for urging the coil spring is attached. The pole core 9 and the plunger 5 form an air gap 30 as shown when the plunger 5 is in the position shown in the region on the right side of the alternate long and short dash line in FIG. 1. When it is in the position shown in the area on the left side of the one-dot chain line, it disappears.

The cylindrical plunger 5 is provided slidably in the through space 4 of the plunger guide 3 in the vertical direction in FIG. 1, and is made of a relatively inexpensive magnetic material such as iron. As described above, the plunger 5 has the concentric void portion 6 having an opening at the upper end of FIG. 1 (the left end in FIG. 3), and the coil spring 7 is provided in the void portion 6.
However, it is interposed with the other end fixed. A pair of projecting holes 2 communicating with the void 6 is formed in a portion of the outer peripheral portion of the plunger 5 near the lower end in FIG. 1 (right end in FIG. 3).
8 is formed. These through holes 28 are provided to prevent water, dust, and other impurities from collecting in the clearance between the plunger 5 and the plunger guide 3. A recessed portion is formed at the lower end portion of the plunger 5 in FIG. 1 (right end portion in FIG. 3). It is provided.

On the outer peripheral portion of the plunger 5, a plurality of ridges having a smooth curved end as shown in FIG. 4 or a linear end as shown in FIG. A plurality of ridges are formed at substantially equal intervals. By making the outer peripheral portion of the plunger 5 into such a shape,
Water can be circulated between the gap 6 and the clearance between the plunger 5 and the plunger guide 3.

The corner portion of the outer peripheral portion of the plunger 5 indicated by reference numeral C is square-cut as shown in an enlarged view in FIG.

Further, in the plunger 5 according to this embodiment,
At the lower end of FIG. 1 (the right end in FIG. 3), a notch 29 having a rectangular cross section having a length c1 in the direction parallel to the axial direction of the plunger 5 and a length b2 in the radial direction of the plunger 5 is formed. ing. The notch 29 is in a state in which the plunger 5 is in pressure contact with the diaphragm unit 15 and the diaphragm valve closes the flush water flow passage of the automatic faucet, the automatic toilet bowl cleaning device, etc. (that is, the lower end of the plunger 5 from the plunger guide 3 In the protruding state), it exists at a position separated from the yoke 13 as shown in a region on the right side of the alternate long and short dash line in FIG. Therefore, when a magnetic flux is generated from the coil 1 in this state, the magnetic flux passes through the entire width a1 of the yoke 13, and a magnetic circuit having a width extending over the entire width a1 of the yoke 13 is formed.

On the other hand, the notch 29 is in a state where the plunger 5 is separated from the diaphragm unit 17 and the diaphragm valve opens the cleaning water flow path (that is, the lower end of the plunger 5 and the bottom surface of the yoke 13 are flush with each other). (State), as shown in the region on the left side of the alternate long and short dash line in FIG. Therefore, when a magnetic flux is generated from the coil 1 in this state, the magnetic flux passes through the width a2 obtained by subtracting the length c1 of the notch 29 from the total width a1 of the yoke 13, so that the magnetic flux is narrowed down. A magnetic circuit having a width extending over the width a2 in 13 is formed. Therefore, the magnetic resistance is equivalently increased.

In the weak current holding solenoid having the above structure, the same energization as in the conventional weak current holding solenoid is performed. First, at time t ₁ , reference numeral 3 in FIG.
When the first current indicated by 1 is applied to the coil 1, the notch 29 is located away from the yoke 13, so that the magnetic flux generated from the coil 1 passes through the entire width a _{1 of the} yoke 13. As a result, the plunger 5 is sucked upward from the position shown in the region on the right side of the alternate long and short dash line in FIG. 1 and displaced to the position shown in the region on the left side of the alternate long and short dash line in FIG.

When the plunger 5 reaches the above-mentioned position, the notch 29 comes to a position facing the yoke 13, so that the magnetic flux generated from the coil 1 passes through the width a2.

When the plunger 5 is displaced to the above position (t2), the coil 1 is energized to switch from the first current 31 to the second current indicated by reference numeral 33 in FIG. The value of the second current is set so that the coil 1 can obtain a holding force of a magnitude that can oppose the biasing force of the coil spring 7.

Next, when the supply of the second current is stopped at the time t3, the plunger 5 is moved to the above position by the urging force of the coil spring 7 (that is, the position shown in the region on the left side of the alternate long and short dash line in FIG. 1). To the original position (that is, the position shown in the area on the right side of the alternate long and short dash line in FIG. 1).

[1] When the plunger 5 is held at the position shown in the region on the left side of the alternate long and short dash line in FIG. 1 by the energization of the second current, the relationship shown by the following formula is established.

Fi + Fr + Ff> Fs + Fg (1) However, Fi: Force to attract the plunger 5 generated by the second current Fr: Force to attract the plunger 5 due to the residual magnetism generated by the first current Ff: The plunger 5 and the plunger Frictional force Fs generated with the guide 3: Spring force of the coil spring 7 at the time of latching (when the diaphragm valve closes the washing water passage): Self weight of the plunger 5 Here, a slight current according to the present embodiment The holding solenoid is
As shown in (4), it is attached to a diaphragm valve that operates in the vertical direction, and when the plunger 5 operates in the vertical direction, Ff = 0.

Further, when the minute current holding solenoid according to the present embodiment is attached to the diaphragm valve which operates in the horizontal direction and the plunger 5 operates in the horizontal direction,
Fg = 0.

[2] When the plunger 5 is in the position shown in the area on the right side of the alternate long and short dash line in FIG. 1, the following (2)
It is necessary to set the spring force Fs so that the relationship shown by the formula is established.

Fr + Ff <Fs + Fg (2) Generally, since Fr >> Ff and Fr >> Fg, Ff≈0, Fg
Considering ≈0, the above equation can be simplified as Fi + Fr> Fs (3).

Here, together with the suction force Fr, the spring force Fs.
The value of the second current that obtains the minimum value of the suction force Fi capable of holding the above-mentioned suction state of the plunger 5 (that is, the minimum value of the second current, hereinafter referred to as "limit current Ih"). In order to obtain, it is assumed that Fi + Fr = Fs (that is, Fi = Fs-Fr) (4).

Next, if the margin of the spring force Fs with respect to the attraction force Fr is set to m times, it can be expressed as Fs = mFr. By substituting Eq. (5) into Fs of Eq. (4) and rearranging, Fi = Fs-Fr = (m-1) Fr (6) is obtained.

Here, Fi and Fr are

[Equation 1]

[Equation 2] Is expressed as.

Substituting the equation (7) into Fi in the equation (6) and substituting the equation (8) into Fr in the equation (6),

[Equation 3] Is established. The above equation (9) is a relational expression applied to a weak current holding solenoid having the cutout portion 29, such as the weak current holding solenoid according to the present embodiment.

On the other hand, such as conventional weak current hold solenoid, for the notch without 29 weak current hold solenoid, the limiting current Q'the I _{h 'reluctance,} the remanence B _r By expressing it as', the same as in the above equation (9)

[Equation 4] Can be expressed as

Solving the above equation (9) for Ih,

[Equation 5] To get

Similarly, solving the above equation (10) for Ih ',

[Equation 6] To get

Here, the ratio of the residual magnetic flux density Br when the notch 29 is present and the residual magnetic flux density Br ′ when the notch is not present is given by: Br / Br ′ = b. The ratio of the magnetic resistance Q when the portion 29 is present and the magnetic resistance Q ′ when there is no cutout portion, in other words, the cutout portion 2
The ratio of the magnetic permeability μ when 9 is present and the magnetic permeability μ ′ when there is no notch is taken as Q / Q ′ = μ ′ / μ = q (14).

Ih obtained by the above equation (11) is given by
Dividing by Ih 'obtained by the above equation (12) and substituting b of the equation (13) and q of the equation (14) into the quotient, Ih / Ih' = (QBr) / (Q ' Br ') = qb (15) is obtained. By solving the above equation (15), Ih / Ih
´ is needed. Here, μ ′ expressed by the above equation (14)
As shown in FIG. 8, a B (magnetic flux density) -H (magnetic field strength) characteristic curve 35 of a conventional low-current-holding solenoid generated at a magnetic field strength H1 and a point 47 showing the maximum magnetic flux density in the characteristic curve 35. It is expressed by the inclination (−tan θ ′) of the line segment 48 connecting with and with respect to the horizontal axis. Further, μ expressed by the above equation (14) is the BH characteristic curve 37 of the slight current holding type solenoid of this embodiment, which is generated in the magnetic field strength H1 in the same manner as described above, and the maximum magnetic flux density in the characteristic curve 37. The slope of the line segment 50 connecting the point 49 shown with respect to the horizontal axis (-tan
θ).

Br 'represented by the above equation (13) is shown in FIG.
As shown in, the coordinate value of the vertical axis of the intersection of the line segment 52 obtained by translating the line segment 48 to the origin O and the characteristic curve 35 is represented by Br. Origin O
And the characteristic curve 37
It is represented by the coordinate value on the vertical axis of the intersection point with. Where Ih above
/ Ih '(that is, the ratio of the limiting current value Ih in the weak current holding solenoid having the notch in the plunger to the limiting current value Ih' in the weak current holding solenoid not having the notch in the plunger) is 1 Whether or not it is smaller, that is, whether or not Ih <Ih 'is confirmed by FIG.

From the above equation (14), q = μ '/ μ, so q = μ' / μ = -tan θ '/-tan θ, and from FIG. 8, | -tan θ'|> | -tan θ | From | −tan θ
′ | / | −tan θ |> 1. This is because the point 49 indicating the maximum magnetic flux density exists in the area surrounded by the B-H characteristic curve 35, and the B-H characteristic curve 37 is surrounded by the B-H characteristic curve 35. It also indicates that it exists within. Further, from FIG. 8, Br <Br ', that is, b = Br / Br'<1. That is, in the unsaturated region as shown in FIG. 8, 1 / q> b, and therefore 1> qb, and Ih / Ih ′ <1 holds from the equation (15).

Therefore, the limiting current value Ih for energizing the weak current holding solenoid according to this embodiment can be made smaller than the limiting current value Ih 'for energizing the conventional weak current holding solenoid.

Therefore, when the notch 29 is provided in the plunger 5, it is possible to suppress the residual magnetism generated by the energization of the first current, thereby reducing the biasing force of the coil spring 7. Therefore, since the second current can be reduced, it is possible to reduce power consumption.

The above description relates to one embodiment of the present invention and does not mean that the present invention is limited to the above description. In the present embodiment, the shape of the notch 29 formed at the tip of the plunger 5 is described as a rectangular shape, but it may be a tapered shape. In any case, the material cost is reduced by providing the cutout portion. Further, the notch 29 may be filled with a material having a low magnetic permeability.

In this case, even if the space between the upper end surface 201 of the plunger 5 and the portion indicated by the reference numeral 202 is not in contact with the plunger guide 3 as in the above-mentioned embodiment, the upper end surface 201 of the plunger 5 is removed. The rattling prevention effect can be improved by contacting the plunger guide 3 with a portion in the vicinity and filling the notch 29 with a material having a low magnetic permeability so as to contact the plunger guide 3. Although the notch 29 reaches the position facing the yoke 13 at the start of suction in the above embodiment, the above condition I _h / I _h ′ is satisfied even if the notch 29 reaches the yoke 13 at the start of suction. be able to.

[0048]

As described above, according to the present invention,
Even if the yoke, plunger, etc. that form the magnetic circuit are made of a relatively inexpensive magnetic material such as iron, the residual magnetism generated at the start of the suction operation of the plunger can be reduced, and the above-mentioned members remain. It is possible to provide a weak current-holding solenoid capable of reducing the amount of energization during holding of the attracted state, as in the case of being formed of a high-cost magnetic material having small magnetism.

[Brief description of drawings]

FIG. 1 is a diagram showing a weak current holding type solenoid according to an embodiment of the present invention.

FIG. 2 is a view showing the weak current holding type solenoid of FIG. 1 and a diaphragm valve used as a flush water flow path opening / closing valve of an automatic faucet, an automatic toilet bowl cleaning device, and the like.

FIG. 3 is a sectional view of a plunger according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of the plunger seen from the direction of line AA in FIG.

5 is a partial cross-sectional view of the plunger seen from the direction of the line BB in FIG.

6 is a partially enlarged cross-sectional view of a portion indicated by reference sign C in FIG.

FIG. 7 is an explanatory diagram showing an exciting current supplied to a coil.

FIG. 8 is a weak current holding solenoid B according to the present embodiment.
-H characteristic and BH of conventional weak current holding solenoid
The figure which compared the characteristic.

Claims (4)

(57) [Claims] 1. A magnetic circuit of an electromagnet includes a plunger biased in one direction, and a drive current for attracting the plunger to the electromagnet in a direction opposite to the bias is applied, and the following drive current is applied. In the solenoid adapted to hold the plunger at the suction completion position by applying a small current, the plunger has a low magnetic permeability portion having a lower magnetic permeability than the other portions, and the position of the low magnetic permeability portion in the plunger. Is a position included in the magnetic circuit that contributes to holding and suction at least when the plunger is at the suction completion position.
As a result, the magnetic efficiency during suction decreases and
A weak current holding solenoid, which is selected in a position that can reduce 2. The weak current holding solenoid according to claim 1, wherein the low magnetic permeability portion is a cutout portion. 3. The weak current holding type solenoid according to claim 1, wherein the low magnetic permeability portion is formed of a material having a magnetic permeability lower than that of a magnetic material forming the plunger. solenoid. 4. The weak current-holding solenoid according to claim 1, wherein the position of the low magnetic permeability portion of the plunger at the plunger is at the position when the plunger starts suctioning. A weak current-holding solenoid, characterized in that the low magnetic permeability portion is not included in the magnetic circuit.