JP4936969B2 - Magnetostrictive torque sensor shaft manufacturing equipment - Google Patents

Description

The present invention relates to a manufacturing ZoSo location of the magnetostrictive torque sensor shaft provided by electroplating the magnetostrictive film on the surface of the torque sensor shaft body.

  Conventionally, as a torque sensor for detecting torque, a magnetostrictive torque sensor shaft having a magnetostrictive film provided on the surface of a torque sensor shaft body is provided, and a detection coil is provided on the outer periphery of the portion of the torque sensor shaft provided with the magnetostrictive film. In accordance with the configuration in which the tensile force or compressive stress is applied to the magnetostrictive film due to the torque acting on the torque sensor shaft, and the magnetic permeability of the magnetostrictive film changes due to the inverse magnetostrictive effect thereby, the change in the magnetic permeability is changed. What detects by a detection coil is provided (for example, refer patent document 1).

And in this thing, what provided the said magnetostrictive film in the surface of the said torque sensor shaft main body by electroplating is provided (for example, refer patent document 2).
Further, although not specified as a magnetostrictive film, as a general plating method and apparatus, a plurality of objects to be processed are arranged at equal intervals on the circumference, and the objects to be processed are moved around the circumference, There is one in which the object to be processed is plated while rotating the object to be processed itself (see, for example, Patent Document 3).
JP 2003-98017 A JP 2005-3622 A JP-A-4-63287

For example, an alloy of nickel (Ni) and iron as a magnetostrictive material has a saturation magnetostriction constant (λ) that varies depending on the material composition (content ratio of nickel and iron) (see FIG. 13). The horizontal axis indicates the nickel ratio, and the remaining ratio is the iron content ratio).
When this material is applied to the magnetostrictive film of a magnetostrictive torque sensor, the sensitivity of the magnetostrictive torque sensor changes due to the change in inductance of the detection coil obtained from the torque acting on the shaft due to the change in the saturation magnetostriction constant. Will do.

  On the other hand, when an alloy of nickel and iron is formed by electrolytic plating, as shown in Patent Document 2, a plurality of nickel electrodes are arranged in the plating solution, and the torque sensor shaft body is arranged at the center between them. A magnetostrictive film made of an alloy of nickel and iron is formed on the surface of the torque sensor shaft main body by arranging and supplying a nickel electrode as a positive electrode and a shaft as a negative electrode and energizing between them.

FIG. 14 shows the current density (the value obtained by dividing the current value [A] by the surface area [dm ² ] of the shaft) and the nickel composition deposited on the magnetostrictive film when the magnetostrictive film is formed by electrolytic plating. (Remaining iron component). The shaft is 8 [mm] in diameter, the length is 20 [mm], and the magnetostrictive film thickness is 15 [μm] for each current density. The time is adjusted so that the electrolytic plating is performed.

As is apparent from FIG. 14, when the current density increases, the nickel component decreases (the iron component increases), and when the current density exceeds a certain current density, the nickel component tends to saturate.
FIG. 15 shows the relationship between the current density and the thickness of the magnetostrictive film. The same torque sensor shaft body as described above was subjected to electrolytic plating for 45 minutes for each current density. This is when a magnetostrictive film is formed. Thus, it can be seen that the thickness of the magnetostrictive film is in a relationship that is approximately proportional to the current density.

  It is important that the magnetostrictive film not only has a uniform composition but also a uniform thickness. When the thickness partially changes, the linearity of the torque sensor characteristics, output fluctuation, temperature characteristics, etc. are affected. . Conventionally, as one of the solutions, the magnetostrictive film is made uniform by rotating or swinging up and down the torque sensor shaft body arranged at the center between the plurality of nickel electrodes in the plating solution. I was trying.

However, it can only plate one shaft at a time, and in order to produce in large quantities, it is necessary to provide a large number of plating apparatuses, which increases the cost of manufacturing equipment. In addition, the installation location of the plating apparatus is widely required, so that a great production cost is generated.
On the other hand, as shown in Patent Document 3, a plurality of objects to be processed are arranged on the circumference at equal intervals, the objects to be processed are moved around the circumference, and the objects to be processed themselves are also included. In the case where the object to be treated is plated while being rotated, a plurality of pieces can be produced, so that it is not necessary to provide many plating apparatuses, which is advantageous in terms of manufacturing cost.

  However, the current flowing between each of the torque sensor shafts, which are a plurality of workpieces, and the nickel electrode is difficult to be uniform due to the difference in the contact resistance of each part, and the current density flowing between each of them is different. . For this reason, as described above, the composition and thickness of the magnetostrictive film to be plated are different for each torque sensor shaft, and as a result, the characteristics and accuracy of the torque sensor are likely to vary.

The present invention has been made in view of the above-described circumstances, and therefore the object thereof is to produce a magnetostrictive torque sensor shaft capable of producing a plurality of magnetostrictive torque sensor shafts with a uniform composition and thickness of the magnetostrictive film. to provide a ZoSo location.

In the magnetostrictive torque sensor shaft manufacturing apparatus of the present invention, in the apparatus in which a magnetostrictive film is provided on the surface of the torque sensor shaft main body by electrolytic plating, the main shaft and a plurality of torque sensor shaft main bodies provided around the main shaft are supported. Corresponding to the number of torque sensor shaft main body support portions, and a rotation mechanism for rotating the torque sensor shaft main body support portion around the main shaft and rotating the torque sensor shaft main body support portion. A plurality of rotating electrodes provided in each of the torque sensor shaft main body support portions, the rotation electrodes connected to the rotation electrodes of the main shaft, and the torque sensor shaft main body support portions are arranged opposite to each other. A common plating electrode and positive and negative output terminals, and the positive output terminal is connected to the plating electrode. A constant current circuit provided with a negative output terminal connected to the rotating electrode of the main shaft, and a plurality of the constant current circuits are provided corresponding to the number of torque sensor shaft body support portions, And a reference voltage is compared with a voltage generated by a current flowing between each rotating electrode of the main shaft and the plating electrode, and a current corresponding to the difference is compared with each rotating electrode of the main shaft. wherein by flowing between the plating electrode, characterized in that it is configured to flow a constant current between the plating electrode and the rotary electrode of the main shaft.

According to manufacturing ZoSo location of the magnetostrictive torque sensor shaft having the above structure, since it is produced in the magnetostrictive torque sensor shaft are provided in plurality, there is no need to provide a large number of plating apparatus, the manufacturing cost is advantageous. In addition, the torque sensor shaft main body is revolved and rotated, and electrolytic plating is performed to supply power between the torque sensor shaft main body and the plating electrode in a constant current circuit for each torque sensor shaft main body. Since the magnetostrictive film is provided on each surface of the torque sensor shaft body, the current flowing between the torque sensor shaft body and the plating electrode causes differences in contact resistance between parts and differences in individual resistance of the torque sensor shaft body. Etc., and the current density flowing between them is constant. Therefore, the composition and film thickness of the magnetostrictive film to be plated are made uniform, and the characteristics and accuracy of the torque sensor can be ensured satisfactorily.

Hereinafter, an embodiment (one embodiment) of the present invention will be described with reference to FIGS.
First, FIG. 6 shows the overall structure of the torque sensor 1, which has a magnetostrictive torque sensor shaft 2 in the center. The magnetostrictive torque sensor shaft 2 includes a torque sensor shaft main body 3 formed in a cylindrical shape with a metal such as stainless steel, and a magnetostrictive film 4 provided on two adjacent surfaces in the middle portion in the horizontal direction in the drawing. Details thereof will be described later.

  A detection coil 5 is wound around a bobbin 6 on the outer periphery of the portion of the magnetostrictive torque sensor shaft where the magnetostrictive film 4 is provided. Two connection pins 7 made of a conductive material are inserted into and fixed to the bobbin 6, and each end of the detection coil 5 is connected to the inside of the bobbin 6 of the connection pin 7.

  Bearings 8 are mounted on both sides of the portion of the torque sensor shaft body 3 where the magnetostrictive film 4 is provided, and a frame 9 is mounted from both the bearings 8 to the bobbin 6. A relay substrate 11 on which various electrical components 10 are mounted is attached to the outside of the left side portion of the frame 9 in the drawing, and the tip end portion of the connection pin 7 protruding from the frame 9 is mounted on the relay substrate 11. Are connected by soldering or the like.

  The various electrical components 10 mounted on the relay substrate 11 detect the torque acting on the magnetostrictive torque sensor shaft in cooperation with the detection coil 5 and are covered by the torque acting on the magnetostrictive torque sensor shaft. The torque acting on the magnetostrictive torque sensor shaft is detected by detecting the change in the magnetic permeability according to the change in the magnetic permeability of the magnetostrictive film 4 due to the stress.

  Here, the magnetostrictive torque sensor shaft 2 will be described in detail with reference to FIGS. 7 and 8. The magnetostrictive torque sensor shaft 2 is, for example, rolled onto the two surface portions of the torque sensor shaft body 3. By forming the concave stripes 12 and the convex stripes 13 alternately, a magnetostrictive film 4 made of an alloy of nickel and iron, for example, is formed on the outer peripheral surface (surface of the torque sensor shaft body 3) by electrolytic plating. Forming. The pattern of the concave stripe portion 12 and the convex stripe portion 13 is inclined with respect to the axial direction so that the stress due to the torque acting on the magnetostrictive torque sensor shaft 2 is effectively applied to the magnetostrictive film 4, and in particular, the stress is magnetostrictive film. 4 is formed so as to extend at an angle of about 45 degrees so as to be most effective at 4, and further, the left ridge 12 and ridge 13 and the right ridge 12 and ridge in the drawing. 13, the direction of the inclination is reversed so that the opposite stress is exerted on the left magnetostrictive film 4 and the right magnetostrictive film 4 in the figure.

  FIG. 1 shows an apparatus for manufacturing the magnetostrictive torque sensor shaft 2 having a main shaft 14 in the center. An upper rotary support 15 is attached to the upper part of the main shaft 14, and a lower rotary support 16 is attached to the lower part. A plurality of (four in the example shown in FIG. 2) torque sensor shaft bodies 3 are arranged between the rotation supports 15 and 16 at equal intervals on the circumference of the main shaft 14, respectively. The torque sensor shaft body 3 is supported by the shaft body support portions 17 and 18, and the portions other than the portion where the magnetostrictive film 4 is provided are masked by the mask members 19 and 20 in the supported state. It has become.

  Around the torque sensor shaft main body support portions 17 and 18, the torque sensor shaft main body support portions 17 and 18 are opposed to all of the torque sensor shaft main body support portions 17 and 18. A common plating electrode 21 having a cylindrical shape is disposed, and the plating electrode 21 and the torque sensor shaft main body support portions 17 and 18 (all of the torque sensor shaft main body 3) are connected to all the mask members 19 and 20. At the same time, it is arranged in the plating solution 23 in the plating tank 22. In this case, the plating electrode 21 is a nickel electrode.

Although not shown, the above structure is provided with a rotation mechanism having a motor as a drive source and a gear transmission mechanism and the like. By this rotation mechanism, arrows A and B in FIG. As shown in the figure, the torque sensor shaft body support portions 17 and 18 (torque sensor shaft body 3) are moved around the circumference of the main shaft 14 (revolution) and the torque sensor shaft body support portions 17 and 18 are rotated. It is designed to rotate (spin) itself.
Note that the rotational speed of the torque sensor shaft main body support portions 17 and 18 is a non-integer multiple of the rotational speed of the main shaft 14, thereby avoiding that their rotations are synchronized, and electrolytic plating described later is performed. It is done more uniformly.

  On the other hand, the upper rotating support 15 (and thus the main shaft 14) is provided with a plurality of ring-shaped fixed electrodes 24 corresponding to the number of the torque sensor shaft bodies 3, and the rotating electrodes in contact with the fixed electrodes 24, respectively. 25, and the torque sensor shaft main body support portion 17 is provided with a rotation electrode 26 connected to the rotation electrode 25, respectively, and thereby the torque sensor shaft main body that revolves and rotates as described above. Electric power is supplied to the support portion 17 (torque sensor shaft body 3).

  For the above power feeding, a constant current circuit 27 is provided for each of the plurality of torque sensor shaft bodies 3 corresponding to the number of the torque sensor shaft bodies 3, and the constant current circuits 27 are positive (+ ) Output terminal 28 and negative (-) output terminal 29, of which positive output terminal 28 is connected to the plating electrode 21, and the negative output terminal 29 is connected to the upper rotary support 15 (main shaft 14). The fixed electrodes 24 are connected to the rotating electrodes 25, respectively. Accordingly, the negative output terminal 29 is connected to the torque sensor shaft main body 3 through the rotating electrode 26. As a result, from the positive output terminal 28, the plating electrode 21-plating solution 23-torque. Sensor shaft main body 3-torque sensor shaft main body support portion 17-rotating electrode 26-rotating electrode 25-fixed electrode 24-negative output terminal 29, and a current flow.

FIG. 3 shows one of the constant current circuits 27 as a representative in detail. In FIG. 3, E indicates a main power source of DC 12 [V], for example, to which the positive output terminal 28 is connected. On the other hand, the negative output terminal 29 is connected to the collector c of the npn transistor 30 which is an amplifying element.
A resistor 31 that is a current detection element is connected to the emitter e of the transistor 30, and the resistor 31 corresponds to the current that flows between the positive output terminal 28 and the negative output terminal 29 as described above. A voltage is generated, and the voltage signal is input to the negative terminal 34 of the comparison operation element 33 via the filter circuit 32.

  A voltage signal corresponding to a set current value (reference) formed by a variable resistor 36 and a fixed resistor 37 as current setting means is input to the positive terminal 35 of the comparison operation element 33 via a resistor 38. The comparison operation element 33 performs a comparison operation between the input of the positive terminal 35 and the input of the previous negative terminal 34, and an output current corresponding to the input difference is supplied to the transistor 30 via the resistor 39. To base b. Thereby, a current corresponding to the input difference flows between the positive output terminal 28 and the negative output terminal 29 between the collector c and the emitter e of the transistor 30, and thus, A constant current set by the variable resistor 36 and the fixed resistor 37 flows between the positive output terminal 28 and the negative output terminal 29.

FIG. 4 shows the functional effect of the constant current circuit 27. As shown in FIG. 4A, the voltage applied between the output terminals 28 and 29 includes the fixed electrode 24 and the rotating electrodes 25 and 26, respectively. The current flowing between the output terminals 28 and 29 is as shown in (b) of the figure, although the change occurs due to the difference in contact resistance between the contact portions of the torque sensor shaft and the individual resistance of the torque sensor shaft body 3. , Become constant.
FIG. 5 shows the current when a constant voltage is applied to the same portion without using the constant current circuit 27, and it can be seen that the current value fluctuates with the passage of time.

  Therefore, in the case of the above-described configuration, the plating electrode 21 is in a situation where the plurality of torque sensor shaft bodies 3 supported by the torque sensor shaft body support portions 17 and 18 rotate while revolving around the main shaft 14 in the plating solution 23. Constant current flows between the positive output terminal 28 and the negative output terminal 29 of the constant current circuit 27 including the space between the torque sensor shaft body 3 and the entire torque sensor shaft body 3. Parts other than the masked part are electroplated to form the magnetostrictive film 4.

  Therefore, in the case of the above configuration, a plurality of magnetostrictive torque sensor shafts 2 can be produced, and it is not necessary to provide many plating apparatuses, which is advantageous in terms of manufacturing cost. The torque sensor shaft body 3 is revolved and rotated, and electroplating is performed to supply power between the torque sensor shaft body 3 and the plating electrode 21 by a constant current circuit 27 for each torque sensor shaft body 3. Since the magnetostrictive film is provided on each surface of the plurality of torque sensor shaft bodies 3, the current flowing between the torque sensor shaft body 3 and the plating electrode 21 is applied to the fixed electrode 24 and the rotating electrodes 25 and 26. Even if there is a difference in the contact resistance of the contact portion or a difference in the individual resistance of the torque sensor shaft body 3, the current density flowing between them becomes constant. Therefore, the composition and film thickness of the magnetostrictive film 4 to be plated are made uniform for all the torque sensor shaft bodies 3, and the characteristics and accuracy of the torque sensor 1 can be ensured satisfactorily.

  FIG. 9 shows the effect of the configuration described above. FIG. 9A shows the degree of fluctuation of the nickel composition of the magnetostrictive film 4 and FIG. 9B shows the degree of fluctuation of the film thickness of the magnetostrictive film 4. In many cases, the set values are as many as possible (variation value “0”), and the uniformity is high. On the other hand, in the conventional device not using the constant current circuit 27, as shown in FIGS. 10 (a) and 10 (b), the variation degree (a) of the nickel composition of the magnetostrictive film 4 and the magnetostrictive film 4 The film thickness variation degree (b) is low as the set value (variation value “0”) is low, and the uniformity is low.

FIG. 11 also shows the effect of the configuration described above, and shows how the torque sensor 1 using the magnetostrictive torque sensor shaft 2 having the magnetostrictive film 4 changes in output with respect to shaft rotation. It can be seen that the output fluctuation is small for 3 samples as an example. Thereby, the characteristics and accuracy of the torque sensor 1 can be ensured satisfactorily. On the other hand, in the conventional device manufactured without using the constant current circuit 27, as shown in FIG. 12, it can be seen that there are many output fluctuations for a plurality of samples (for example, five samples). In this case, the characteristics and accuracy of the torque sensor cannot be ensured satisfactorily.
It should be noted that the present invention is not limited only to the embodiment described above and shown in the drawings, and in particular, the specific materials and other points of the magnetostrictive film can be appropriately changed and implemented without departing from the scope of the invention.

Schematic configuration diagram of a manufacturing apparatus showing an embodiment of the present invention Sectional drawing which follows the XX line of FIG. Electric circuit diagram of constant current circuit The figure which shows the functional effect of the constant current circuit Fig. 4 (b) equivalent of the conventional one Cross section of torque sensor Side view of magnetostrictive film part of magnetostrictive torque sensor shaft FIG. 7 is an enlarged sectional view taken along line YY in FIG. The figure which shows the effect of this invention Figure 9 equivalent to the conventional one The figure which shows the different effect of this invention Figure 11 equivalent figure of the conventional one Diagram showing the relationship between magnetostrictive material composition and saturation magnetostriction constant The figure which shows the relationship between the current density at the time of magnetostrictive film formation and the nickel composition of a magnetostrictive film The figure which shows the relationship between the current density at the time of magnetostrictive film formation and the thickness of a magnetostrictive film

Explanation of symbols

  In the drawings, 1 is a torque sensor, 2 is a magnetostrictive torque sensor shaft, 3 is a torque sensor shaft body, 4 is a magnetostrictive film, 14 is a main shaft, 17 is a torque sensor shaft body support, 21 is a plated electrode, and 25 and 26 are Rotating electrode, 27 is a constant current circuit, 28 is a positive output terminal, 29 is a negative output terminal, 30 is a transistor (amplifying element), 31 is a resistance (current detection element), 33 is a comparison operation element, and 37 is a variable resistance (Current setting means) is shown.

Claims (1)

In an apparatus for providing a magnetostrictive film on the surface of the torque sensor shaft body by electrolytic plating,
The spindle,
A plurality of torque sensor shaft body support portions provided at equal intervals around the main shaft;
A rotation mechanism for rotating the torque sensor shaft body support portion around the main shaft and rotating the torque sensor shaft body support portion;
A plurality of rotating electrodes provided corresponding to the number of the torque sensor shaft main body support portions on the main shaft;
A rotation electrode provided in each of the torque sensor shaft body support portions and connected to the rotation electrode of the main shaft;
A common plating electrode disposed to face all of the torque sensor shaft body support,
Comprising a positive and negative output terminal, a positive current terminal connected to the plating electrode, and a constant current circuit provided with a negative output terminal connected to the rotating electrode of the main shaft,
A plurality of the constant current circuits are provided corresponding to the number of the torque sensor shaft main body support portions, and each is connected to a power source and is generated by a current flowing between each rotating electrode of the main shaft and the plating electrode. By comparing and calculating a voltage and a reference voltage, and passing a current according to the difference between each rotating electrode of the main shaft and the plating electrode, between the rotating electrode of the main shaft and the plating electrode An apparatus for manufacturing a magnetostrictive torque sensor shaft, characterized in that a constant current is allowed to flow through .

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