JP6670077B2 - Bonding method - Google Patents

Description

  The present invention relates to a bonding method for bonding a magnet for detecting a valve opening of a control valve to a valve shaft.

  In a chemical plant or the like, a control valve (valve) is used for process control of a flow rate. In recent years, a flow control valve in which a function of a flow meter is added to the control valve is increasing.

  The flow control valve includes, for example, a valve (valve element) for controlling the flow rate of a fluid, a set value of a valve opening (set opening) sent from a higher-level device, and a measured value of a valve opening of a control valve ( And an electric actuator for controlling a valve opening by rotating a valve shaft connected to the valve body by driving a drive motor (electric motor) based on the deviation. It has a structure as a motor-operated valve.

  The electric actuator includes, as a functional unit for measuring the actual opening degree of the control valve, a displacement amount detector that detects the valve opening degree of the control valve as a displacement amount of a valve shaft, and as the displacement amount detector For example, a potentiometer and a non-contact angle sensor (magnetic sensor) are well known (see Patent Document 1).

JP 2014-224736 A

  Prior to the present invention, the inventor of the present application considered developing a specific measuring device in which a calorimeter function was added to a flow control valve. As a result of the examination, it became clear that there were the following problems.

  In order for a flow control valve with the function of a calorimeter to be recognized as a specific measuring instrument, its structure and instrumental differences must satisfy the technical standards specified by a ministerial ordinance. However, it has been clarified that, when the configuration of the conventional flow control valve is applied as it is, the above technical level cannot be satisfied with respect to the flow rate measurement accuracy.

  Generally, in a flow control valve having a configuration in which the function of a flow meter is added to the above-described motor-operated valve, the flow control valve is based on the pressure on the primary and secondary sides of the valve and the actual valve opening (actual opening). It measures (calculates) the flow rate of the fluid inside. Therefore, in order to increase the measurement accuracy of the flow rate, it is necessary to increase the detection accuracy of the valve opening.

  However, when a potentiometer is used as a component for measuring the valve opening, the potentiometer has a sliding portion, and the linearity of the resistance value cannot be guaranteed. It's not easy.

  Then, the inventor of the present application examined using a magnetic sensor that is a non-contact angle sensor instead of the potentiometer.

FIG. 9 is a diagram schematically illustrating a cross-sectional structure of a main part of an electric actuator using a magnetic sensor for a flow control valve, studied by the present inventors.
As shown in FIG. 9, for example, in an electric actuator 100 that operates a rotary control valve such as a butterfly valve, a valve shaft (stem) 5 is rotatably supported in a housing 8, and a valve body of the valve shaft 5 is provided. A magnet 3 is fixed via a magnet holder 4 to an end opposite to a side to which a magnet (not shown) is connected, and a non-contact angle sensor (magnetic sensor) 6 is provided at a position facing the magnet 3 via a substrate 7. And install it.

FIG. 10 is a diagram showing a planar structure of the magnet and the magnet holder when viewed from the direction E in FIG.
As shown in FIG. 10, the magnet 3 is formed in a substantially circular shape in a plan view, and is fixed to the surface 4 </ b> A of the magnet holder 4 such that both the N pole and the S pole face the magnetic sensor 6. Accordingly, when the electric actuator 100 rotates the valve shaft 5, the magnet 3 disposed on the valve shaft 5 rotates, and the magnetic flux density around the magnet 3 changes. By detecting the change in the magnetic flux density by the magnetic sensor 6 disposed opposite to the magnet 3, the rotation angle of the valve shaft can be detected, and the opening degree of the control valve can be measured.

  However, in order to measure the valve opening with high accuracy in the electric actuator 100, the magnet 3 must be arranged with high accuracy with respect to the magnetic sensor 6. For example, depending on the employed magnetic sensor, the valve opening cannot be measured with high accuracy unless the deviation Δx1 between the detection unit of the magnetic sensor 6 and the center of the magnet is set to 0.05 mm or less.

  In order to perform the positioning of the magnet with high accuracy, for example, it is necessary to use a device such as a mounter for mounting electronic components and the like on a substrate, but since these devices are very expensive, a flow control valve is required. This is not a viable option considering the production volume.

  Further, even if the positioning of the magnet can be performed with high accuracy, it is not easy to fix the magnet to the magnet holder. That is, the magnet is fixed to the magnet holder by the adhesive, but in order to arrange the magnet with high accuracy, the type of the adhesive and the type of the dispenser for applying the adhesive must also be considered.

  For example, the amount of the adhesive applied to install a magnet having an outer diameter of Φ8 ± 0.1 at the center of a magnet holder having an outer diameter of Φ10 with high accuracy is 1 μL. In order to apply such a small amount of adhesive, unless the adhesive and the dispenser to be used are properly selected, the production cost is increased.

  For example, when a two-part adhesive is used, it is easy to control the timing of curing the adhesive, but the two-part adhesive has a high viscosity, so that an inexpensive pneumatic dispenser has a very small amount. Cannot be applied with high precision. Therefore, it is necessary to use a more accurate and expensive dispenser, which causes an increase in manufacturing cost.

  On the other hand, when a one-part adhesive is used, the viscosity is lower than that of a two-part adhesive, so it is possible to apply a minute amount with high precision using an inexpensive dispenser. It is not easy to control the timing of curing. For example, when a one-component adhesive that cures at room temperature is used, the magnet must be mounted immediately after the adhesive is applied to the mounting surface of the magnet holder, and before the positioning of the magnet is completed. The adhesive may be hardened at the same time. On the other hand, when using an adhesive that cures at a temperature higher than room temperature, the adhesive is applied to fix the magnet to the magnet holder, and the magnet holder on which the positioned magnet is placed is placed in a high-temperature space such as an oven. You need to move them one by one. For this reason, the work efficiency in mass-producing the flow control valve is poor, and the production cost is increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to perform low-cost bonding of a magnet for detecting the opening degree of a control valve to a valve shaft.

  The method for bonding magnets according to the present invention uses a positioning jig (10) comprising a base (1) at least partially formed in a cylindrical shape, and using a positioning magnet (10) on a cylindrical magnet holder (4). A bonding method for bonding (3), wherein a first step of fitting one end of each of a plurality of magnet holders into a plurality of recesses (120) formed in a main surface of a base (12), respectively. (S1), a second step (S2) of applying a one-component adhesive that cures at a temperature higher than room temperature to each of the other ends of the plurality of magnet holders or the plurality of magnets, and after the second step, A third step (S3) of placing the magnet on the other end of the magnet holder, and after the third step, the other end of the magnet holder on which the magnet is placed is placed in the opening (2A) of the cylindrical portion of the positioning jig. ) Is inserted in the fourth step (S4), and the positioning jig is inserted. The base number of the magnet holder is placed adhesive characterized by comprising a fifth step of placing the temperature environment to cure (S5).

  In the bonding method described above, the cylindrical portion of the base opens one end (1A) of the base and forms a cylindrical internal space having a cross section perpendicular to the axial direction of the base having a diameter (La) longer than the diameter of the magnet. And a first hole (2A) which fits loosely with the outer peripheral surface of the rod-shaped member on which the magnet is mounted, and a conical or truncated conical internal space coaxial with the first hole. The internal space includes a second hole (2B) in which the diameter of a cross section perpendicular to the axial direction of the base continuously decreases toward the other end (1C) of the base.

  In the above description, as an example, reference numerals in the drawings corresponding to the components of the invention are described in parentheses.

  As described above, according to the present invention, the magnet for detecting the valve opening of the control valve is bonded to the valve shaft at low cost.

FIG. 1 is a sectional view showing a main part of a positioning jig used in the bonding method according to the embodiment of the present invention. FIG. 2 is a plan view showing a main part of the positioning jig when viewed from the direction C in FIG. FIG. 3 is a plan view showing a main part of the positioning jig when viewed from the direction A in FIG. FIG. 4 is a cross-sectional view of the positioning jig when the positioning jig is fitted to a magnet holder on which a magnet is mounted. FIG. 5 is a diagram showing a planar structure of a tray used in the bonding method according to the embodiment of the present invention. FIG. 6 is a diagram showing a cross-sectional structure of a tray used in the bonding method according to the embodiment of the present invention. FIG. 7 is a flowchart showing the flow of the bonding method according to the embodiment of the present invention. FIG. 8 is a cross-sectional view illustrating a main part of a positioning jig according to another embodiment. FIG. 9 is a diagram schematically illustrating a cross-sectional structure of a main part of an electric actuator using a magnetic sensor for a flow control valve, studied by the present inventors. FIG. 10 is a diagram showing a planar structure of the magnet and the magnet holder when viewed from the direction E in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the method for bonding magnets according to the present embodiment, in the manufacturing process of the electric actuator 100 shown in FIG. 9 described above, the magnet 3 for detecting the valve opening is connected to the non-contact angle sensor (magnetic This is a method for accurately installing the sensor at a position on the valve shaft 5 facing the sensor 6.

  In the bonding method according to the present embodiment, first, the magnet 3 to which the adhesive has been applied is placed on each of the plurality of magnet holders 4 arranged on the dedicated tray using a dedicated positioning jig, and thereafter, The adhesive is cured by placing a tray in which the magnet holders 4 with the positioning jigs fitted therein are arranged in a high-temperature environment. Hereinafter, the bonding method will be described in detail.

(1) Positioning jig First, a positioning jig used in the bonding method according to the present embodiment will be described.

1 to 3 are views showing the structure of a positioning jig used in the bonding method according to the embodiment of the present invention.
FIG. 1 shows a cross-sectional structure of a positioning jig 10 (hereinafter, also simply referred to as “jig 10”) in a BB cross section. FIG. 2 shows the jig 10 when viewed from a C direction. FIG. 3 shows the planar structure of the jig 10 when viewed from the A direction.

  The jig 10 is an instrument for installing the magnet 3 formed in a substantially circular shape in plan view on the magnet holder 4 for detecting the valve opening.

  Here, the magnet holder 4 is a rod-shaped (pillar-shaped) component serving as a pedestal for mounting the magnet 3 on the distal end portion of the valve shaft 5, and is made of a non-magnetic material (for example, aluminum or copper). . As shown in FIG. 9, the magnet holder 4 has a surface 4A on which the magnet 3 is placed at one end, and is fitted to the valve shaft 5 at the other end. For example, the tip portion of the magnet holder 4 on the surface 4A side has a columnar shape, and is formed in a substantially circular shape in plan view as shown in FIG.

Specifically, the jig 10 includes a columnar base 1 and holes 2 formed in the base 1.
The base 1 is made of, for example, a non-magnetic material such as aluminum, copper, or resin. As shown in FIGS. 2 and 3, at least a part of the base 1 is formed in a cylindrical shape, for example, and has a substantially circular shape in a plan view.

  The hole 2 is a through hole including a first hole 2A, a second hole 2B, and a third hole 2C, and is formed in the base 1 by, for example, a known metal processing technique.

  The first hole 2A is a hole that opens the end 1A of the base to form a cylindrical internal space, and has a cross section perpendicular to the axial direction of the base 1 having a diameter La. Specifically, the diameter La of the first hole 2 </ b> A is longer than the diameter of the magnet 3 for detecting the valve opening degree described above, and the outer diameter of the cylindrical magnet holder 4 on which the magnet 3 is mounted is the same as the first diameter. The inner wall surface S of the hole 2A has such a length as to be fitted with a clearance fit. For example, the fitting tolerance between the magnet holder 4 and the first hole 2A is such that when the outer diameter of the magnet holder 4 serving as the shaft is Φ10g5, the inner diameter of the first hole 2A is Φ10H6.

  The third hole 2C is a hole that opens the end 1C of the base to form a cylindrical internal space, and has a cross section perpendicular to the axial direction of the base 1 having a diameter Lc. Specifically, as shown in FIGS. 2 and 3, the third hole 2C is formed substantially coaxially with the first hole 2A in a substantially circular shape in plan view. The diameter Lc of the third hole 2C is shorter than the diameter of the magnet 3.

  The second hole 2B forms a truncated conical internal space coaxial with the first hole 2A, and the diameter of a cross section of the internal space perpendicular to the axial direction of the base 1 is directed toward the other end 1C of the base 1. It is a hole that decreases continuously. Specifically, the inner wall surface of the second hole 2B is formed between the inner wall surface of the first hole 2A on the other end 1C side of the base 1 and the inner wall surface of the third hole 2C on the one end 1A side of the base 1. It is formed in a tapered shape connecting the ends.

  Here, the second hole 2B is formed, for example, at the center of the inner wall surface S of the first hole 2A and the inner wall surface of the tapered second hole 2B (at the other end 1C side of the base 1 of the first hole 2A). A deviation between the end and the middle point of a line connecting the end of the third hole 2C on the one end 1A side of the base 1) is formed to be, for example, 0.01 mm.

  FIG. 4 is a cross-sectional view of the jig according to the present embodiment when the jig is fitted to a magnet holder on which a magnet is placed.

  When the magnet 3 is fixed to the magnet holder 4, as shown in FIG. 4, after the magnet 3 is placed on the surface 4 </ b> A of the magnet holder 4, the jig 10 is fitted to the tip of the magnet holder 4 on the surface 4 </ b> A side. . Specifically, the jig 10 is fitted into the magnet holder 4 until the edge 3A of the magnet 3 contacts the inner wall surface of the second hole 2B of the jig 10. As a result, the magnet 3 can be accurately arranged at the center of the magnet holder 4.

  For example, in order to install the magnet 3 having an outer diameter of Φ8 ± 0.1 at the center of the magnet holder 4 having an outer diameter of Φ10g5, the inner diameter of the first hole 2A is set to Φ10H6, and the inner wall S of the first hole 2A is formed. When manufacturing the jig 10 in which the deviation from the center of the inner wall surface of the second hole 2B is 0.01 mm, the deviation width Δx2 between the center of the magnet 3 and the magnet holder 4 is set to 0.02 mm or less by design. Can be.

  Actually, when the inventor of the present application prototyped the jig 10 under the above conditions and positioned the magnet 3 using the jig 10, the deviation width Δx2 between the center of the magnet 3 and the magnet holder 4 was 0.005. It turned out that it fits in the range of -0.015 mm. Therefore, if the jig 10 is used, the displacement Δx1 between the detection unit of the magnetic sensor 6 and the center of the magnet 3 can be reduced to 0.05 mm or less.

(2) Tray Next, a dedicated tray used in the bonding method according to the present embodiment will be described.
5 and 6 are views showing the structure of a tray used in the bonding method according to the embodiment of the present invention.
FIG. 5 shows a planar structure of the tray 12, and FIG. 6 shows a cross-sectional structure of the tray 12.

  The tray 12 is an instrument for collectively placing a plurality of magnet holders 4 on which the magnets 3 coated with the adhesive are placed in a high-temperature environment. The tray 12 is made of, for example, a material such as a metal or a resin having heat resistance sufficiently higher than a temperature required for curing the adhesive.

  Specifically, the tray 12 has a plurality of recesses 120 formed on the main surface 12A. Each of the concave portions 120 is formed, for example, at equal intervals along the X direction and the Y direction of the main surface 12A.

  Each recess 120 has a shape corresponding to the shape of the magnet holder 4. Specifically, as shown in FIG. 6, when the magnet holder 4 is inserted into the recess 120 of the tray 12, the magnet holder 4 has a shape that can be stabilized on the tray 12.

  More specifically, the recess 120 has a depth Lf (length in the Z direction) into which the end opposite to the surface 4A of the magnet holder 4 can be inserted and the magnet holder 4 can be held on the tray 12. ) And an inner diameter Le (length in the X and Y directions). For example, assuming that the axial length of the magnet holder 4 is Lg, the depth Lf of the recess 120 is about １ ／ to ３ of Lg. When the outer diameter of the magnet holder 4 is Ld, the inner diameter Le of the recess 120 is “Ld + ΔL”. Here, ΔL is, for example, about 0.5 m to 1 m.

  In order to more stably hold the magnet holder 4 on the tray 12, it is preferable that the magnet holder 4 and the recess 120 be fitted with a loose fit.

(3) Method of bonding magnet using positioning jig Next, a method of bonding magnet 3 using jig 10 and tray 12 will be specifically described.
FIG. 7 is a flowchart showing a processing procedure of the bonding method according to the embodiment of the present invention.

  As shown in FIG. 7, first, a plurality of magnet holders 4 on which the magnets 3 are not placed are fitted into the respective recesses 120 of the tray 12 at the ends opposite to the surface 4A, and It is placed (S1).

  Next, an adhesive is applied to the surface 4A of each magnet holder 4 placed on the tray 12 (S2). Here, the adhesive is a one-component adhesive that cures at a temperature higher than room temperature (for example, about 100 ° C.).

  Specifically, in step S2, a predetermined amount of adhesive is applied to the surface 4A of the magnet holder 4 using a liquid dispensing device. Here, as the liquid fixed-rate discharge device, for example, an air discharge type dispenser using air pressure can be used. The amount of the adhesive applied is, for example, about 1 μL when a magnet having an outer diameter of Φ8 ± 0.1 is fixed to the magnet holder 4 having an outer diameter of Φ10. The adhesive is applied, for example, to the central portion of the surface 4A of each magnet holder 4.

  Next, the magnets 3 are mounted on the respective surfaces 4A of the plurality of magnet holders 4 to which the adhesive has been applied (S3). The placement of the magnet 3 may be performed manually or using an apparatus.

  Next, the jig 10 is put on each of the plurality of magnet holders 4 (S4). Specifically, as described above, the end of the magnet holder 4 on the surface 4A side on which the magnet 3 is mounted and the second hole 2A of the jig 10 are fitted into each magnet holder 4 so as to be inserted. The jig 10 is put on the holder 4 (see FIGS. 4 and 5).

  Next, the tray 12 is placed in a high temperature environment (S5). Specifically, as shown in FIG. 7, the tray 12 on which the plurality of magnet holders 4 covered with the jig 10 are placed is placed in an oven for curing the adhesive, and the oven is required for curing the adhesive. (In the above example, about 100 ° C.).

Thereafter, when a sufficient time has passed for the adhesive to harden, the tray 12 is taken out, and the jigs 10 inserted into the respective magnet holders 4 are removed.
As described above, the magnet 3 can be fixed on the magnet holder 4.

  As described above, according to the magnet bonding method according to the present embodiment, the valve opening detection magnet can be bonded onto the valve shaft at low cost. That is, by using the tray 12, the plurality of magnet holders 4 covered with the jig 10 can be collectively placed in a high-temperature environment such as an oven, so that a one-component type adhesive that cures at a temperature higher than room temperature. Even when the agent is used, the magnet 3 can be efficiently fixed to the plurality of magnet holders 4. Also, by using the tray 12, a one-component adhesive having a relatively lower viscosity than that of the two-component adhesive can be used. For example, an inexpensive air-dispensing dispenser using air pressure is used. Can be.

  Also, by using the positioning jig 10, the positioning of the valve opening degree detecting magnet can be performed with high accuracy and at low cost. That is, after the magnet 3 is placed on the magnet holder 4 to which the adhesive is applied, the magnet holder 4 is inserted into the first hole 2A of the jig 10 to form the jig 10 into a tapered shape. The position of the magnet 3 can be determined by the contact between the inner wall surface of the second hole 2B and the end 3A of the magnet 3. Thereby, the magnet 3 can be accurately positioned with respect to the magnetic sensor 6 by hand without using an expensive device as described above.

  As described above, according to the magnet bonding method according to the present embodiment, the positioning of the valve opening detection magnet installed on the valve shaft and the bonding of the valve opening detection magnet on the valve shaft are performed with high accuracy. It can be performed accurately and at low cost. Therefore, by applying the magnet bonding method according to the present embodiment and manufacturing the flow control valve using the above-described magnetic sensor, the detection accuracy of the valve opening of the flow control valve can be improved. Thus, it is possible to realize a flow control valve with high flow rate measurement accuracy at lower cost.

  In the jig 10, the third hole 2 </ b> C is formed in the other end 1 </ b> C of the base 1, so that the worker can mount the magnet 3 during the operation by the magnet bonding method according to the present embodiment. Since the presence or the like can be visually checked, the occurrence of a work error can be prevented, and improvement in work efficiency can be expected. Further, since the hole 2 is formed as a through-hole by the third hole 2C, the processing of the jig 10 itself is facilitated, which contributes to a reduction in the manufacturing cost of the jig 10.

  As described above, the invention made by the present inventors has been specifically described based on the embodiments. However, it is needless to say that the present invention is not limited thereto, and various changes can be made without departing from the gist of the invention. No.

  For example, in the above-described embodiment, the case where the adhesive is applied onto the magnet holder 4 after the plurality of magnet holders 4 are installed on the tray 12 is illustrated (see FIG. 7), but the present invention is not limited to this. For example, after applying the adhesive to the plurality of magnet holders 4, the magnet holders 4 may be placed on the tray 12, or the jig 10 may be placed on the magnet holder 4 on which the magnets 3 are placed via the adhesive. , The magnet holders may be placed on the tray 12.

Further, in the above-described embodiment, the case where the hole 2 is a through-hole is illustrated. However, when it is not necessary to consider the processing of the jig or the like, the jig 10A shown in FIG. The hole 2 does not have to be a through-hole without forming the three-hole portion 2C.
When the third hole 2C is not formed, the second hole 2B may have a conical shape instead of a truncated cone shape.

  10, 10A ... jig, 1 ... base, 1A, 1C ... end of base 1, 2 ... hole, 2A ... first hole, 2B ... second hole, 2C ... third hole, 3 ... magnet, 4 magnet holder, 4A surface, 5 valve stem, 6 magnetic sensor, 7 board, 8 housing, 12 tray, 12A main surface, 120 recess.

Claims (3)

A bonding method for bonding a columnar magnet to a columnar magnet holder, using a positioning jig at least partially composed of a base formed in a cylindrical shape,
A first step of fitting one end of each of the plurality of magnet holders into a plurality of recesses formed in the main surface of the base;
A second step of applying a one-component adhesive that cures at a temperature higher than room temperature to the other end of each of the plurality of magnet holders or the plurality of magnets;
A third step of placing the magnet on the other end of each of the plurality of magnet holders after the second step;
A fourth step of, after the third step, inserting the other ends of the plurality of magnet holders on which the magnets are placed into openings of the cylindrical portion of the positioning jig;
The fifth step of placing a plurality of said magnets holder the magnet is placed is the base on which the positioning jig is placed in fitting inserted state, the temperature environment in which the previous SL adhesive cures And a bonding method. The bonding method according to claim 1,
The cylindrical portion of the positioning jig,
One end of the base is opened, and a cross section perpendicular to the axial direction of the base forms a cylindrical internal space having a diameter longer than the diameter of the magnet, and an outer periphery of the magnet holder on which the magnet is mounted. A first hole that fits into the surface with a loose fit;
A conical or frustoconical internal space is formed coaxially with the first hole, and a diameter of a cross section of the internal space perpendicular to the axial direction of the base continuously decreases toward the other end of the base. And a second hole. The bonding method according to claim 2,
The second hole has the truncated cone shape,
The base further includes a third hole that opens the other end of the base and forms a cylindrical internal space having a cross section perpendicular to the axial direction of the base having a diameter shorter than the diameter of the magnet,
The inner wall surface of the second hole is formed by connecting the end of the inner wall of the first hole on the other end side of the base and the end of the inner wall of the third hole on the one end side of the base. A bonding method, wherein the bonding method is formed in a tapered shape.

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