WO2012173261A1 - Torque sensor and manufacturing method therefor - Google Patents
Torque sensor and manufacturing method therefor Download PDFInfo
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- WO2012173261A1 WO2012173261A1 PCT/JP2012/065436 JP2012065436W WO2012173261A1 WO 2012173261 A1 WO2012173261 A1 WO 2012173261A1 JP 2012065436 W JP2012065436 W JP 2012065436W WO 2012173261 A1 WO2012173261 A1 WO 2012173261A1
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- rotating shaft
- glass film
- torque sensor
- magnetostrictive
- flame
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/101—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means
- G01L3/102—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means involving magnetostrictive means
- G01L3/103—Details about the magnetic material used
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
- C23C4/06—Metallic material
Definitions
- the present invention relates to a torque sensor of a type that detects the magnitude of torque acting on a rotating shaft (drive shaft) by a change in magnetic permeability of a magnetostrictive portion provided on the surface of the rotating shaft.
- FIG. 1 A general structure of the above-described type of torque sensor is shown in FIG.
- a rotating shaft 1 that receives torque is supported by a housing 3 via a bearing 2, and magnetostrictive portions A and B are formed on a part of the surface of the rotating shaft 1.
- the coils C and D are arranged at positions near the outer circumferences of the magnetostrictive portions A and B inside the housing 3.
- a magnetic material is formed on the surface of the shaft 1 in a spiral shape that is inclined in opposite directions with respect to the axial direction as shown in the drawing (that is, a magnetic film or protrusion is spirally formed).
- the housing 3 is also provided with an amplifier board 4 and a signal line connector 5 as shown in the figure.
- tensile stress and compressive stress are generated in the magnetostrictive portions A and B, respectively.
- the magnetic permeability of each magnetostrictive portion A and B is increased and decreased by the opposing magnetostrictive effects.
- a voltage output proportional to the magnitude of the torque can be obtained by performing DC conversion and differential amplification of both. .
- Patent Document 1 a document relating to such a torque sensor.
- the rotating shaft itself is formed of a ferromagnetic material having a high magnetic permeability as a configuration of the magnetostrictive portion. It is shown that there is an example of thermal spraying.
- An amorphous alloy (including metallic glass) is suitable as the magnetic material constituting the magnetostrictive portion. This is because the magnetostrictive portion of the torque sensor is required to have two characteristics of high permeability and high magnetostriction, and an amorphous alloy is preferable in that respect and can provide high sensitivity characteristics.
- Patent Document 3 describes that it is preferable to employ a high-speed spraying process such as high-speed flame spraying (HVOF) in order to form a metallic glass film on the surface of the base material (base material). .
- HVOF high-speed flame spraying
- JP 2010-2414 A Japanese Patent Publication No. 63-20031 JP 2010-10668 A
- the inventors consider that the torque detection characteristics of the torque sensor are not sufficient by any of the examples described in the above-mentioned documents, and there is room for further improvement.
- the magnetostrictive portion of the rotating shaft is clearly disadvantageous in terms of sensitivity compared to the case of using an amorphous alloy when it is composed of only a general magnetic material.
- an amorphous alloy ribbon is fixed to the surface of the rotating shaft by attaching it with an adhesive, etc., sufficient detection characteristics cannot be obtained due to poor adhesion to the rotating shaft, output hysteresis, short life It also affects the problem.
- the method is high-speed, so the time that the metal powder is in the flame is short, so that the metal powder does not melt Since it is laminated on the shaft surface in the supercooled liquid phase state, the adhesion between the alloy film and the rotating shaft seems to be insufficient, and the torque detection sensitivity is not high.
- the high-speed thermal spraying process has a limitation that it is necessary to use an amorphous metal powder having a particle size of about 30 ⁇ m or less, which is disadvantageous in terms of manufacturing cost.
- the present invention solves the above-described problems and provides a torque sensor improved in terms of torque detection characteristics and manufacturing cost, and a method for manufacturing the torque sensor.
- the torque sensor of the present invention has a magnetostrictive part including a metal glass film on the surface of the rotating shaft, and the metal glass film in the magnetostrictive part injects a flame containing the metal powder to melt the metal powder. It is characterized in that the flame is formed on the surface of the rotary shaft by thermal spraying in which the flame is cooled by the cooling gas from outside before reaching the surface of the rotary shaft.
- This torque sensor has the following operational features. That is, a) Since the surface of the rotating shaft has a magnetostrictive portion including a metallic glass film, the magnetostrictive portion has two characteristics of high permeability and high magnetostriction. For this reason, this torque sensor exhibits superior characteristics regarding torque detection as compared with the case without the coating (see FIG. 1).
- the metallic glass film is formed on the surface of the rotating shaft by thermal spraying, the hysteresis is extremely small compared to the example in which the ribbon of the alloy is fixed on the surface of the rotating shaft (see FIG. 2). Unlike the case of using an adhesive or the like for fixing the ribbon, it is considered that the adhesion between the alloy film and the rotating shaft is high.
- the metallic glass film is laminated on the rotating shaft as a film simultaneously with the amorphization by thermal spraying, there is also an advantage that the magnetostrictive part is formed easily and quickly.
- the above-mentioned method of injecting a flame containing metal powder to melt the metal powder and cooling the flame with a cooling gas from the outside adopts this torque sensor.
- the torque detection characteristics are even better than those sprayed by (see FIG. 3). It is considered that since the metal powder is once melted, the adhesion of the metal glass film to the surface of the rotating shaft is increased, and the torque of the rotating shaft is easily transmitted to the alloy film. Further, unlike the case of the high-speed spraying process, there is an advantage that even a metal powder having a large particle size (about 40 ⁇ m or more) can be used.
- the rotation axis is a non-magnetic material and the amorphous alloy of the magnetostrictive portion is Fe—Co—Si—B—Nb-based metallic glass.
- the rotating shaft is a magnetic material, as described above, a magnetostrictive portion can be formed simply by forming a helical projection or the like on the surface thereof, and torque can be detected without providing a magnetic film.
- the rotating shaft is a magnetic material, it is affected by an external magnetic field, so that the torque detection sensitivity decreases.
- a magnetostrictive part is formed by using a nonmagnetic material for the rotating shaft and forming a metallic glass film on its surface, it is less susceptible to external magnetic fields and, due to the nature of the metallic glass film, The detection characteristics are extremely high (see FIG. 4). That is, as long as a metal glass sprayed coating can be formed, any material rotation shaft can be applied as a torque sensor. Further, when the amorphous alloy film of the magnetostrictive portion is Fe—Co—Si—B—Nb-based metallic glass, the amorphous forming ability is high, and it is advantageous in terms of magnetic characteristics and mechanical characteristics (FIG. 7A). (See (b) and (c)).
- a metal glass film is formed on the surface of the rotating shaft by the thermal spraying in a state where the temperature of the flame and the surface temperature of the rotating shaft are controlled to be constant. Since the flame for thermal spraying needs to melt the metal powder and be rapidly cooled with a cooling gas, its temperature needs to be sufficiently controlled. However, according to the tests by the inventors, the surface temperature of the rotating shaft during thermal spraying must be sufficiently controlled. This is because it is confirmed that the sensitivity and hysteresis of the torque sensor including the magnetostrictive portion formed by the thermal spraying differ depending on the surface temperature of the rotating shaft during thermal spraying (see FIGS. 5 and 6).
- the difference between the sensitivity and hysteresis occurs because, for example, if the surface temperature is low, the degree of adhesion of the molten metal powder to the surface of the rotating shaft decreases, so hysteresis occurs, but the film becomes amorphous and the sensitivity increases. On the other hand, if the temperature is high, the degree of adhesion increases and no hysteresis occurs. However, it is presumed that the amorphous ratio of the film decreases and the sensitivity decreases. Therefore, the surface temperature of the rotating shaft during thermal spraying needs to be measured by an appropriate thermometer or the like and controlled to an appropriate temperature range (300 to 500 ° C.).
- the magnetostrictive portion of the torque sensor has a configuration in which concave portions and convex portions are alternately arranged linearly on the surface of the rotating shaft, and the metal glass film is formed so as to fill the concave portions (see FIG. 10). It is preferable that the metal glass film is formed on the entire region including the concave portions and the convex portions and then polished so that the metal glass film on the surface of the convex portions adjacent to the metal glass film is eliminated.
- Such a magnetostrictive part can be relatively easily manufactured by a method in which a metal glass film is widely formed by thermal spraying on the surface of the rotating shaft including irregularities, and then the film is polished.
- the metallic glass film is formed so as to fit in the recess, the film is particularly highly integrated with the rotating shaft and is not easily peeled off. Will also be expensive.
- the portions where the metal glass film is formed and the portions where the metal glass film is not formed are alternately arranged in a line having an acute angle of 45 degrees with respect to the rotation axis in the magnetostrictive portion, the torque detection characteristic is enhanced.
- the magnetostrictive portion of the torque sensor is also configured by alternately arranging the portions where the metallic glass film is formed and the portions where the metallic glass film is not formed on the surface of the rotating shaft (see FIG. 10). After the metal glass film is formed on the entire surface, the non-formed part of the metal glass film may be removed by shot blasting by covering a part of the surface of the rotating shaft with a mask.
- Such a magnetostrictive portion is also relatively easily configured by thermal spraying and then shot blasting performed by covering the magnetostrictive portion with a mask (having an opening such as a slit at a position corresponding to the non-formed portion). can do.
- the removal method is not limited to shot blasting, and may be a chemical process such as etching after the magnetostrictive portion is coated with a resin or a mechanical process such as cutting.
- the magnetostrictive portion of the torque sensor is constructed by alternately arranging the portions where the metal glass film is formed and the portions where the metal glass film is not formed on the surface of the rotating shaft (see FIG. 10). It is also possible that the metal glass film of the above-mentioned formation part is formed by covering a part of the surface of the rotating shaft with a mask. Such a magnetostrictive portion can also be easily configured by the above-described thermal spraying performed by covering the magnetostrictive portion with a mask (having an opening such as a slit at a position corresponding to the formation portion). The magnetostrictive portion of the torque sensor is formed by alternately arranging the portions where the metallic glass film is formed and the portions where the metallic glass film is not formed on the surface of the rotating shaft. The metal glass film of the above-mentioned formation part may be directly formed. Such a magnetostrictive part can also be easily configured by a precision sprayed composite machine.
- the torque sensor according to the invention described above when the magnetostrictive portion is configured on the surface of the rotating shaft, a) the rotating shaft is preheated, and b) the thermal spray is maintained on the surface with the flame temperature kept constant.
- a metallic glass film on the magnetostrictive portion by c) and repeatedly rotating the rotating shaft and applying the flame to the rotating shaft surface and deflecting from the rotating shaft surface when forming the film.
- the temperature is maintained on the surface of the rotating shaft. By doing so, it is possible to form a preferable metallic glass film on the surface of the rotating shaft by the above thermal spraying while managing the flame temperature and the surface temperature of the rotating shaft to be constant.
- the temperature of the surface of the rotating shaft can be maintained within a certain range (see FIG. 9). That's why. By doing so, it is possible to form a metal glass film that has excellent adhesion and integrity to the surface of the rotating shaft and a high amorphization rate, and as a result, a torque sensor having excellent detection characteristics can be manufactured.
- a metal powder having a diameter of 40 ⁇ m or more including a crystalline powder may be used.
- Such a metal powder can be obtained at a lower cost than a powder having a smaller diameter or an amorphous powder (amorphized powder), so that the cost required for thermal spraying, that is, the construction of the magnetostrictive portion can be reduced.
- the use of such an inexpensive metal powder is one of the advantages unique to the present invention that is different from high-speed spraying processes such as high-speed flame spraying.
- FIGS. 1-10 It is a diagram which shows a sensor output (vertical axis) when a torque (horizontal axis) is applied to the rotating shaft of the torque sensor, and shows a difference due to the surface temperature of the rotating shaft during thermal spraying of the metallic glass film. It is a diagram which shows a sensor output (vertical axis) when a torque (horizontal axis) is applied to the rotating shaft of the torque sensor, and shows a difference due to the surface temperature of the rotating shaft during thermal spraying of the metallic glass film.
- 7A, 7B, and 7C shows magnetostriction and holding power, mechanical properties, and amorphous forming ability of an Fe—Co—Si—B—Nb-based metallic glass as an amorphous alloy film in the magnetostrictive portion. It is a figure which shows (XRD profile). It is a side view (a part is shown with sectional drawing) which shows the outline
- Magnetostrictive portions A and B as shown in the figure are formed by forming a metallic glass film on the partial surface of the rotary shaft 1 in the torque sensor as shown in FIG. 10 by thermal spraying.
- Each of the magnetostrictive portions A and B is formed by forming a metal glass film in a plurality of spiral shapes that form 45 ° with the axial direction, and alternately arranging the formed portions and the non-formed portions of the film. .
- the directions of the spirals of the magnetostrictive portions A and B are different from each other so that both lines are perpendicular to each other.
- the diameter of the rotating shaft 1 is 8 mm or more, and the line width of the spiral of the formed part and the non-formed part is about 1 to 3 mm.
- the formation part and the non-formation part of the metallic glass film in the magnetostriction parts A and B are formed by the following procedure. That is, 1) By forming a plurality of grooves on the surface of the rotating shaft 1 to form a grooved shaft, concave and convex portions (not shown) along the spiral line (formed portion and non-formed portion) are formed. 2) Form a metallic glass film by spraying the entire area including the concave and convex portions, and 3) remove the convex metallic glass film by polishing the sprayed portion after that. ) Make sure that there is no step between the surface of the metallic glass film (formation part) and the surface of the convex part (non-formation part) adjacent to it.
- the configuration procedure of the magnetostrictive portions A and B is not limited to the above example.
- a metal glass is used by spraying the entire area of the magnetostrictive portions A and B using a shaft (rotary shaft 1) having no groove as described above. After forming the film, a part of the surface of the rotating shaft 1 is covered with a mask (having a spiral slit corresponding to a non-formed part, not shown), and shot blasting is performed, thereby forming a metal glass film forming part. It is also possible to provide a non-formed portion.
- the above thermal spraying is performed by covering a part of the surface of the rotary shaft without the groove with a mask (having a spiral slit corresponding to the formation portion, not shown), so that the same formation portion and non-formation are formed. A portion may be provided.
- a heat resistant paint etc. to give a chevron-like pattern
- forming a sprayed coating on the surface by removing only the sprayed coating on the shoblon pattern using a grinder or shot blast, A chevron pattern may be formed.
- the metal glass film is formed on the rotary shaft 1 by using a flame quenching thermal spraying device 11 shown in FIG. 8 and supported by a support device (supporting the rotary shaft 1 horizontally and rotating it around the axis, not shown). This is performed by spraying on the outer peripheral surface of the rotating shaft 1 that has been moved.
- the thermal spraying device 11 has a double-pipe tubular body 15 or the like that can also be called an external cooling device attached to the front of a powder-type flame spraying gun 12.
- a carrier gas for example, nitrogen
- a supply tube for acetylene and oxygen as fuel for example, acetylene and oxygen
- an internal cooling gas for example, nitrogen
- the internal cooling gas is blown out from a position in contact with the periphery of the nozzle 13 to cool the nozzle 13 and adjust the temperature of the flame.
- a flange-like front plate 14 is fixed to the thermal spray gun 12 around the nozzle 13 near the front end thereof, and a cylindrical body 15 is attached thereto.
- the illustrated cylindrical body 15 separates the flame F from the outside air in the first half of the flame F sprayed by the spray gun 12 (portion close to the nozzle 13; the melting region of the material powder), and flame from the tip of the double pipe.
- Cooling gas for example, nitrogen
- the thermal spraying device 11 sprays a flame F containing material particles from a nozzle 13, melts the material particles with the flame F, and cools the material particles with the cooling gas G, thereby forming a metallic glass film on the surface of the rotary shaft 1.
- the speed of the flame F is set to about 30 to 40 m / s, and the temperature of the flame F is set to 1000 to 1200 ° C.
- the flame F reaches the base material 10 by being surrounded by the cylindrical body 15 and the cooling gas (nitrogen) G ejected therefrom, the amount of oxides in the metal glass film can be suppressed. Since the spray particles can be melted with a sufficient amount of heat, it is possible to use metal powder having a diameter of 40 ⁇ m or more (about 100 ⁇ m or less) including crystalline powder in the thermal spraying using the thermal spraying apparatus 11.
- temperature management is performed so that the surface temperature of the rotating shaft 1 becomes constant along with the temperature of the flame F. This is because, depending on the surface temperature of the rotating shaft 1 during thermal spraying, the torque detection sensitivity of the magnetostrictive portion formed by thermal spraying is different.
- the surface temperature of the rotating shaft 1 is measured by a radiation thermometer, and temperature control is performed during the spraying time t3 as well as during the preheating / falling time t1 and t2 as shown in FIG.
- the rotating shaft 1 is preheated by a burner or the like before the start of spraying, and 2) the temperature lowering time between setting a baffle plate that prevents the sprayed material from scattering from a slightly higher preheating temperature. After confirming a certain temperature drop at t2, spraying is started. 3) During the spraying time t3, while rotating the rotating shaft 1, by repeatedly applying the flame F to the shaft surface and deflecting it from the shaft surface The surface temperature of the rotating shaft 1 is kept substantially constant (within a range of 300 to 500 ° C., depending on the material of the rotating shaft 1 and the sprayed material).
- the flame F is applied to the rotating shaft 1 (the magnetostrictive portion forming portion) that is horizontally supported and rotated, and is sent in the axial length direction (horizontal), and the flame F is sent at one or both ends of the feed. Reciprocate in the direction perpendicular to the shaft length direction (either up or down) to deviate from the shaft surface.
- the surface temperature may be controlled by waiting (stopping) the flame F for a while at a position deviating from the shaft surface.
- the coating formed by thermal spraying is preferably made of, for example, Fe—Co—Si—B—Nb-based metallic glass.
- the metal glass has high amorphous forming ability and is easy to be made amorphous, has excellent magnetic properties, and is difficult to be plastically deformed in mechanical properties. This is because it is preferable. That is, first, FIG. 7A is an example. (Fe 1-x Co x ) 72 B 20 Si 4 Nb 4 is a diagram showing magnetostriction ( ⁇ s) and coercive force (Hc) in Co glass for each concentration of metal, with excellent properties. I understand. FIG.
- FIG. 7 (b) is an investigation of the mechanical properties of the same metallic glass in the same manner, and it can be said that it has good properties in terms of compressive strength, Young's modulus, and plastic elongation.
- FIG. 7C shows an XRD profile of a sprayed film obtained by performing the aforementioned rapid thermal spraying (using the thermal spraying apparatus 11 of FIG. 8) on (Fe 0.5 Co 0.5 ) 72 Si 4 B 20 Nb 4 metallic glass. Indicates. Only the amorphous phase was obtained in any of the two types of sprayed films obtained by changing the spraying conditions, and it was structurally found that the alloy can be easily obtained by spraying.
- the material of the rotating shaft 1 is not ask
- Fig. 1 the surface of the rotating shaft made of carbon steel (SK3) without using metallic glass is shown in Fig. 1 when the metallic glass is sprayed onto the rotating shaft made of carbon steel (SK3) as described above.
- the relationship between the torque (horizontal axis) and the sensor output (vertical axis) is shown for the case where only the irregularities extending spirally are formed to form a magnetostrictive portion.
- a metal glass forming portion and a non-forming portion are provided in the magnetostrictive portion using the grooved shaft described above. It can be seen that the former having a metallic glass film in the magnetostrictive part has a very high sensitivity although the linearity is somewhat inferior to the latter example having no film. When the sensitivity is so high, there is an advantage that the output does not need to be amplified by an amplifier, and therefore there is less noise (no noise filter is required).
- FIG. 2 the case where the metal glass is sprayed on the rotating shaft as described above to form a magnetostrictive portion and the case where an amorphous ribbon formed by a single roll method is attached to the surface of the rotating shaft to form a magnetostrictive portion.
- Both rotating shafts are carbon steel (SK3).
- the magnetostrictive portion is provided with a metal glass forming portion and a non-forming portion using the grooved shaft.
- the thickness of the former metallic glass is 140 to 150 ⁇ m, and the thickness of the latter amorphous ribbon is 25 ⁇ m (attached to the surface of the rotating shaft without grooves).
- FIG. 3 shows the relationship between torque and sensor output when the metallic glass film of the magnetostrictive part is formed by the above-mentioned thermal spraying and when it is formed by high-speed flame spraying (HVOF).
- the rotating shafts are all made of carbon steel (SK3), and the metallic glasses are all (Fe 0.5 Co 0.5 ) 72 Si 4 B 20 Nb 4 as described above.
- HVOF is excellent in output linearity, it can be said that the sensitivity is low and hysteresis occurs.
- the powder material is not sufficiently dissolved, it is assumed that the adhesion to the surface of the rotating shaft is not high.
- FIG. 4 shows the torque and sensor output in the case where the magnetostriction portion is formed by performing the above-described thermal spraying by the apparatus 11 of FIG. 8 on each of the rotating shafts made of titanium (Ti-6Al-4V) and carbon steel (S45C). Shows the relationship.
- the magnetostrictive portion is provided with a metal glass forming portion and a non-forming portion using the grooved shaft. There is no difference in the thickness of the metallic glass film.
- FIG. 4 it can be seen that when the rotating shaft is made of titanium, the linearity is slightly inferior to that of carbon steel, but the sensitivity is greatly improved. This is because the titanium material has a characteristic that it is easy to concentrate the magnetic flux produced by the coil on the magnetostrictive portion because the titanium material has a low elastic modulus and a large amount of strain as compared with the iron material and is non-magnetic.
- FIG. 5 and 6 show the influence of the spraying temperature on the sensor output.
- the magnetostrictive portion is provided with a metallic glass forming portion and a non-forming portion using the spiral grooved shaft having a diameter of 30 mm
- FIG. This is an example in which the formation portion and the non-formation portion of the metal glass film are provided by performing spray blasting after performing thermal spraying on the entire area of the magnetostrictive portion and performing shot blasting as described above.
- the surface temperature of the rotating shaft was measured with a radiation thermometer as described above.
- the emissivity for temperature measurement is set separately. 5 and 6, it is confirmed that the sensitivity and linearity of the torque sensor vary depending on the temperature of the surface of the rotating shaft during thermal spraying. This is presumably because the degree of adhesion of the molten metal to the surface of the rotating shaft and the amorphization rate of the sprayed coating change depending on the temperature. According to the test, the optimum value of the temperature is in the range of 300 to 500 ° C., but the optimum temperature varies depending on the rotating shaft, the material of the sprayed coating, and the shape and size of the sprayed portion.
- the torque sensor having the magnetostrictive portion according to the present invention is more suitable than the torque sensor adopting other methods, materials, and forms as long as the flame and the temperature of the rotating shaft surface during spraying are appropriately controlled. It can be seen that preferable torque detection characteristics can be exhibited.
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Abstract
[Problem] To provide a torque sensor which is improved with regard to the torque detection characteristic, manufacturing cost, and the like, and a manufacturing method therefor.
[Solution] This torque sensor comprises a magnetostrictive section containing an amorphous alloy film (including a metallic glass film) formed on a surface of a rotation shaft. The amorphous alloy film in the magnetostrictive section is formed on the surface of the rotation shaft by means of thermal spray wherein a metallic powder is melted by spraying flame containing the metallic powder, and the flame is cooled by a cooling gas from the outside before the flame reaches the surface of the rotation shaft.
Description
本発明は、回転軸(駆動軸)に作用するトルクの大きさを、その回転軸の表面に設けた磁歪部の透磁率の変化によって検出する形式のトルクセンサに関するものである。
The present invention relates to a torque sensor of a type that detects the magnitude of torque acting on a rotating shaft (drive shaft) by a change in magnetic permeability of a magnetostrictive portion provided on the surface of the rotating shaft.
上記した形式のトルクセンサについて、一般的な構造を図10に示す。トルクを受ける回転軸1が軸受2を介してハウジング3に支持されており、その回転軸1の一部表面に磁歪部A・Bが形成されている。また、ハウジング3の内側で、磁歪部A・Bの各外周に近い位置にコイルC・Dが配置されている。磁歪部A・Bとしては、軸1の表面に、図示のとおり、軸方向に対して互いに逆向きに傾斜した螺旋状に磁性材料を形成する(つまり、磁性体の皮膜や突出部を螺旋状の複数の線として形成する)のが一般的である。ハウジング3には、図示のようにアンプ基板4や信号線用のコネクタ5なども付設されている。
回転軸1にトルクが印加されると、磁歪部A・Bに引張応力と圧縮応力とがそれぞれ発生し、その結果、相反する磁歪効果によって各磁歪部A・Bの透磁率がそれぞれ増加・減少する。この透磁率の変化をもとにコイルC・Dの誘導起電力が発生するため、直流変換や両者の差動増幅を行うことにより、トルクの大きさに比例した電圧出力が得られるわけである。 A general structure of the above-described type of torque sensor is shown in FIG. A rotating shaft 1 that receives torque is supported by ahousing 3 via a bearing 2, and magnetostrictive portions A and B are formed on a part of the surface of the rotating shaft 1. In addition, the coils C and D are arranged at positions near the outer circumferences of the magnetostrictive portions A and B inside the housing 3. As the magnetostrictive portions A and B, a magnetic material is formed on the surface of the shaft 1 in a spiral shape that is inclined in opposite directions with respect to the axial direction as shown in the drawing (that is, a magnetic film or protrusion is spirally formed). Are generally formed as a plurality of lines). The housing 3 is also provided with an amplifier board 4 and a signal line connector 5 as shown in the figure.
When torque is applied to the rotating shaft 1, tensile stress and compressive stress are generated in the magnetostrictive portions A and B, respectively. As a result, the magnetic permeability of each magnetostrictive portion A and B is increased and decreased by the opposing magnetostrictive effects. To do. Since the induced electromotive force of the coils C and D is generated based on the change in the magnetic permeability, a voltage output proportional to the magnitude of the torque can be obtained by performing DC conversion and differential amplification of both. .
回転軸1にトルクが印加されると、磁歪部A・Bに引張応力と圧縮応力とがそれぞれ発生し、その結果、相反する磁歪効果によって各磁歪部A・Bの透磁率がそれぞれ増加・減少する。この透磁率の変化をもとにコイルC・Dの誘導起電力が発生するため、直流変換や両者の差動増幅を行うことにより、トルクの大きさに比例した電圧出力が得られるわけである。 A general structure of the above-described type of torque sensor is shown in FIG. A rotating shaft 1 that receives torque is supported by a
When torque is applied to the rotating shaft 1, tensile stress and compressive stress are generated in the magnetostrictive portions A and B, respectively. As a result, the magnetic permeability of each magnetostrictive portion A and B is increased and decreased by the opposing magnetostrictive effects. To do. Since the induced electromotive force of the coils C and D is generated based on the change in the magnetic permeability, a voltage output proportional to the magnitude of the torque can be obtained by performing DC conversion and differential amplification of both. .
こうしたトルクセンサに関する文献として下記の特許文献1がある。同文献1には、磁歪部の構成として、回転軸自体を透磁率の高い強磁性材料で形成する例があり、また、回転軸の外周面に傾斜した溝を加工したうえ当該溝に磁歪材を溶射する例もある旨が示されている。
磁歪部を構成する磁性材料としては、アモルファス合金(金属ガラスを含む)が適しているとされている。トルクセンサにおける磁歪部には、高透磁率と高磁歪の二つの特性が求められるが、アモルファス合金はその点で好ましく、高感度特性をもたらし得るからである。磁歪部にアモルファス合金を使用することについては、下記の特許文献2等に記載されており、単ロール法で作製したアモルファス合金の薄帯を回転軸表面に固定する旨が示されている。
また下記の特許文献3には、母材(基材)の表面に金属ガラスの皮膜を形成するには、高速フレーム溶射(HVOF)等の高速溶射プロセスを採用するのが好ましいと記載されている。 There is the following Patent Document 1 as a document relating to such a torque sensor. In the same document 1, there is an example in which the rotating shaft itself is formed of a ferromagnetic material having a high magnetic permeability as a configuration of the magnetostrictive portion. It is shown that there is an example of thermal spraying.
An amorphous alloy (including metallic glass) is suitable as the magnetic material constituting the magnetostrictive portion. This is because the magnetostrictive portion of the torque sensor is required to have two characteristics of high permeability and high magnetostriction, and an amorphous alloy is preferable in that respect and can provide high sensitivity characteristics. About using an amorphous alloy for a magnetostriction part, it describes in followingpatent document 2 grade | etc., And shows that the ribbon of the amorphous alloy produced by the single roll method is fixed to the rotating shaft surface.
Patent Document 3 below describes that it is preferable to employ a high-speed spraying process such as high-speed flame spraying (HVOF) in order to form a metallic glass film on the surface of the base material (base material). .
磁歪部を構成する磁性材料としては、アモルファス合金(金属ガラスを含む)が適しているとされている。トルクセンサにおける磁歪部には、高透磁率と高磁歪の二つの特性が求められるが、アモルファス合金はその点で好ましく、高感度特性をもたらし得るからである。磁歪部にアモルファス合金を使用することについては、下記の特許文献2等に記載されており、単ロール法で作製したアモルファス合金の薄帯を回転軸表面に固定する旨が示されている。
また下記の特許文献3には、母材(基材)の表面に金属ガラスの皮膜を形成するには、高速フレーム溶射(HVOF)等の高速溶射プロセスを採用するのが好ましいと記載されている。 There is the following Patent Document 1 as a document relating to such a torque sensor. In the same document 1, there is an example in which the rotating shaft itself is formed of a ferromagnetic material having a high magnetic permeability as a configuration of the magnetostrictive portion. It is shown that there is an example of thermal spraying.
An amorphous alloy (including metallic glass) is suitable as the magnetic material constituting the magnetostrictive portion. This is because the magnetostrictive portion of the torque sensor is required to have two characteristics of high permeability and high magnetostriction, and an amorphous alloy is preferable in that respect and can provide high sensitivity characteristics. About using an amorphous alloy for a magnetostriction part, it describes in following
トルクセンサにおけるトルクの検出特性は、上記の各文献に記載されているいずれの例によっても十分ではなく、さらに改善の余地があると発明者らは考えている。
すなわち、回転軸の磁歪部は、一般的な磁性材料のみで構成する場合には、アモルファス合金を使用するよりも明らかに感度上不利である。またアモルファス合金の薄帯を、接着剤で貼り付けること等により回転軸表面に固定するなら、回転軸との密着性が高くないために十分な検出特性が得られず、出力のヒステリシス、短寿命の問題にも影響をおよぼす。高速フレーム溶射等の高速溶射プロセスによって回転軸表面に金属ガラス皮膜を形成する場合でも、その方法は、高速であるために金属粉末が火炎内にある時間が短く、したがって金属粉末を溶融させることなく過冷却液相状態で軸表面に積層するものであることから、やはり当該合金皮膜と回転軸との密着性が不十分のようで、トルクの検出感度が高くない。高速溶射プロセスについてはさらに、非晶質金属粉末であって粒径が30μm程度以下の微粉を使用せねばならないという制約があり、そのために製造コストの面でも不利である。 The inventors consider that the torque detection characteristics of the torque sensor are not sufficient by any of the examples described in the above-mentioned documents, and there is room for further improvement.
In other words, the magnetostrictive portion of the rotating shaft is clearly disadvantageous in terms of sensitivity compared to the case of using an amorphous alloy when it is composed of only a general magnetic material. Also, if an amorphous alloy ribbon is fixed to the surface of the rotating shaft by attaching it with an adhesive, etc., sufficient detection characteristics cannot be obtained due to poor adhesion to the rotating shaft, output hysteresis, short life It also affects the problem. Even when a metal glass film is formed on the surface of the rotating shaft by a high-speed flame spraying process such as high-speed flame spraying, the method is high-speed, so the time that the metal powder is in the flame is short, so that the metal powder does not melt Since it is laminated on the shaft surface in the supercooled liquid phase state, the adhesion between the alloy film and the rotating shaft seems to be insufficient, and the torque detection sensitivity is not high. Further, the high-speed thermal spraying process has a limitation that it is necessary to use an amorphous metal powder having a particle size of about 30 μm or less, which is disadvantageous in terms of manufacturing cost.
すなわち、回転軸の磁歪部は、一般的な磁性材料のみで構成する場合には、アモルファス合金を使用するよりも明らかに感度上不利である。またアモルファス合金の薄帯を、接着剤で貼り付けること等により回転軸表面に固定するなら、回転軸との密着性が高くないために十分な検出特性が得られず、出力のヒステリシス、短寿命の問題にも影響をおよぼす。高速フレーム溶射等の高速溶射プロセスによって回転軸表面に金属ガラス皮膜を形成する場合でも、その方法は、高速であるために金属粉末が火炎内にある時間が短く、したがって金属粉末を溶融させることなく過冷却液相状態で軸表面に積層するものであることから、やはり当該合金皮膜と回転軸との密着性が不十分のようで、トルクの検出感度が高くない。高速溶射プロセスについてはさらに、非晶質金属粉末であって粒径が30μm程度以下の微粉を使用せねばならないという制約があり、そのために製造コストの面でも不利である。 The inventors consider that the torque detection characteristics of the torque sensor are not sufficient by any of the examples described in the above-mentioned documents, and there is room for further improvement.
In other words, the magnetostrictive portion of the rotating shaft is clearly disadvantageous in terms of sensitivity compared to the case of using an amorphous alloy when it is composed of only a general magnetic material. Also, if an amorphous alloy ribbon is fixed to the surface of the rotating shaft by attaching it with an adhesive, etc., sufficient detection characteristics cannot be obtained due to poor adhesion to the rotating shaft, output hysteresis, short life It also affects the problem. Even when a metal glass film is formed on the surface of the rotating shaft by a high-speed flame spraying process such as high-speed flame spraying, the method is high-speed, so the time that the metal powder is in the flame is short, so that the metal powder does not melt Since it is laminated on the shaft surface in the supercooled liquid phase state, the adhesion between the alloy film and the rotating shaft seems to be insufficient, and the torque detection sensitivity is not high. Further, the high-speed thermal spraying process has a limitation that it is necessary to use an amorphous metal powder having a particle size of about 30 μm or less, which is disadvantageous in terms of manufacturing cost.
本発明は、以上のような課題を解決し、トルクの検出特性や製造コスト等について改善したトルクセンサおよびその製造方法を提供するものである。
The present invention solves the above-described problems and provides a torque sensor improved in terms of torque detection characteristics and manufacturing cost, and a method for manufacturing the torque sensor.
本発明のトルクセンサは、回転軸の表面に金属ガラス皮膜を含む磁歪部を有するもので、上記磁歪部における金属ガラス皮膜が、金属粉末を含む火炎を噴射して金属粉末を溶融させるとともに、当該火炎を、それが回転軸表面に達する前より外側からの冷却ガスにて冷却する方式の溶射によって、上記回転軸の表面に形成されていることを特徴とする。
このトルクセンサには、つぎのような作用的特徴がある。すなわち、
a) 回転軸の表面に金属ガラス皮膜を含む磁歪部を有するので、その磁歪部に高透磁率と高磁歪の二つの特性が備わっている。そしてそのために、当該皮膜のないものに比べ、このトルクセンサはトルク検出に関してすぐれた特性を発揮する(図1参照)。
b) 金属ガラス皮膜を溶射によって回転軸表面に形成することから、当該合金の薄帯を回転軸表面に固定する例に比べてヒステリシスがきわめて少ない(図2参照)。薄帯の固定のために接着剤等を用いる場合とは違って、当該合金皮膜と回転軸との密着性が高いからだと考えられる。また、金属ガラス皮膜は、溶射によって、アモルファス化と同時に皮膜として回転軸上に積層されるため、簡単かつ迅速に磁歪部が形成されるという利点もある。
c) 溶射方法として、金属粉末を含む火炎を噴射して金属粉末を溶融させるとともに、当該火炎を外側から冷却ガスにて冷却する上記の方式を採用することから、このトルクセンサは、高速溶射プロセスにて溶射したものに比べてもさらにトルク検出特性にすぐれている(図3参照)。金属粉末を一旦溶融させるため、回転軸表面に対する金属ガラス皮膜の密着性が高くなり、回転軸のトルクが当該合金皮膜に伝わりやすくなるからと考えられる。また、高速溶射プロセスの場合とは異なり、金属粉末として粒径が大きい(40μm程度以上の)結晶質のものでも使用できるという利点がある。 The torque sensor of the present invention has a magnetostrictive part including a metal glass film on the surface of the rotating shaft, and the metal glass film in the magnetostrictive part injects a flame containing the metal powder to melt the metal powder. It is characterized in that the flame is formed on the surface of the rotary shaft by thermal spraying in which the flame is cooled by the cooling gas from outside before reaching the surface of the rotary shaft.
This torque sensor has the following operational features. That is,
a) Since the surface of the rotating shaft has a magnetostrictive portion including a metallic glass film, the magnetostrictive portion has two characteristics of high permeability and high magnetostriction. For this reason, this torque sensor exhibits superior characteristics regarding torque detection as compared with the case without the coating (see FIG. 1).
b) Since the metallic glass film is formed on the surface of the rotating shaft by thermal spraying, the hysteresis is extremely small compared to the example in which the ribbon of the alloy is fixed on the surface of the rotating shaft (see FIG. 2). Unlike the case of using an adhesive or the like for fixing the ribbon, it is considered that the adhesion between the alloy film and the rotating shaft is high. In addition, since the metallic glass film is laminated on the rotating shaft as a film simultaneously with the amorphization by thermal spraying, there is also an advantage that the magnetostrictive part is formed easily and quickly.
c) As a thermal spraying method, the above-mentioned method of injecting a flame containing metal powder to melt the metal powder and cooling the flame with a cooling gas from the outside adopts this torque sensor. The torque detection characteristics are even better than those sprayed by (see FIG. 3). It is considered that since the metal powder is once melted, the adhesion of the metal glass film to the surface of the rotating shaft is increased, and the torque of the rotating shaft is easily transmitted to the alloy film. Further, unlike the case of the high-speed spraying process, there is an advantage that even a metal powder having a large particle size (about 40 μm or more) can be used.
このトルクセンサには、つぎのような作用的特徴がある。すなわち、
a) 回転軸の表面に金属ガラス皮膜を含む磁歪部を有するので、その磁歪部に高透磁率と高磁歪の二つの特性が備わっている。そしてそのために、当該皮膜のないものに比べ、このトルクセンサはトルク検出に関してすぐれた特性を発揮する(図1参照)。
b) 金属ガラス皮膜を溶射によって回転軸表面に形成することから、当該合金の薄帯を回転軸表面に固定する例に比べてヒステリシスがきわめて少ない(図2参照)。薄帯の固定のために接着剤等を用いる場合とは違って、当該合金皮膜と回転軸との密着性が高いからだと考えられる。また、金属ガラス皮膜は、溶射によって、アモルファス化と同時に皮膜として回転軸上に積層されるため、簡単かつ迅速に磁歪部が形成されるという利点もある。
c) 溶射方法として、金属粉末を含む火炎を噴射して金属粉末を溶融させるとともに、当該火炎を外側から冷却ガスにて冷却する上記の方式を採用することから、このトルクセンサは、高速溶射プロセスにて溶射したものに比べてもさらにトルク検出特性にすぐれている(図3参照)。金属粉末を一旦溶融させるため、回転軸表面に対する金属ガラス皮膜の密着性が高くなり、回転軸のトルクが当該合金皮膜に伝わりやすくなるからと考えられる。また、高速溶射プロセスの場合とは異なり、金属粉末として粒径が大きい(40μm程度以上の)結晶質のものでも使用できるという利点がある。 The torque sensor of the present invention has a magnetostrictive part including a metal glass film on the surface of the rotating shaft, and the metal glass film in the magnetostrictive part injects a flame containing the metal powder to melt the metal powder. It is characterized in that the flame is formed on the surface of the rotary shaft by thermal spraying in which the flame is cooled by the cooling gas from outside before reaching the surface of the rotary shaft.
This torque sensor has the following operational features. That is,
a) Since the surface of the rotating shaft has a magnetostrictive portion including a metallic glass film, the magnetostrictive portion has two characteristics of high permeability and high magnetostriction. For this reason, this torque sensor exhibits superior characteristics regarding torque detection as compared with the case without the coating (see FIG. 1).
b) Since the metallic glass film is formed on the surface of the rotating shaft by thermal spraying, the hysteresis is extremely small compared to the example in which the ribbon of the alloy is fixed on the surface of the rotating shaft (see FIG. 2). Unlike the case of using an adhesive or the like for fixing the ribbon, it is considered that the adhesion between the alloy film and the rotating shaft is high. In addition, since the metallic glass film is laminated on the rotating shaft as a film simultaneously with the amorphization by thermal spraying, there is also an advantage that the magnetostrictive part is formed easily and quickly.
c) As a thermal spraying method, the above-mentioned method of injecting a flame containing metal powder to melt the metal powder and cooling the flame with a cooling gas from the outside adopts this torque sensor. The torque detection characteristics are even better than those sprayed by (see FIG. 3). It is considered that since the metal powder is once melted, the adhesion of the metal glass film to the surface of the rotating shaft is increased, and the torque of the rotating shaft is easily transmitted to the alloy film. Further, unlike the case of the high-speed spraying process, there is an advantage that even a metal powder having a large particle size (about 40 μm or more) can be used.
上記のトルクセンサにおいては、回転軸が非磁性体であり、上記磁歪部のアモルファス合金がFe-Co-Si-B-Nb系金属ガラスであると、さらに好ましい。
もし回転軸が磁性体であれば、前記のとおり、その表面に螺旋状突起部等を形成するだけで磁歪部が構成でき、わざわざ磁性体の皮膜を設けなくともトルクの検出が可能になる。しかし回転軸が磁性体の場合、それが外部磁界の影響を受けるためにトルクの検出感度が低下する。その点、回転軸に非磁性材料を使用して、その表面に金属ガラス皮膜を形成することにより磁歪部を構成するなら、外部磁界の影響を受けにくいうえに金属ガラス皮膜の特質上、トルクの検出特性がきわめて高くなる(図4参照)。すなわち、金属ガラス溶射皮膜が形成可能であれば、あらゆる材料の回転軸がトルクセンサとして適用可能となる。
また、磁歪部のアモルファス合金皮膜がFe-Co-Si-B-Nb系金属ガラスであると、アモルファス形成能が高いうえ、磁気特性および機械的特性の点でも有利である(図7(a)(b)(c)参照)。 In the above torque sensor, it is more preferable that the rotation axis is a non-magnetic material and the amorphous alloy of the magnetostrictive portion is Fe—Co—Si—B—Nb-based metallic glass.
If the rotating shaft is a magnetic material, as described above, a magnetostrictive portion can be formed simply by forming a helical projection or the like on the surface thereof, and torque can be detected without providing a magnetic film. However, when the rotating shaft is a magnetic material, it is affected by an external magnetic field, so that the torque detection sensitivity decreases. In that respect, if a magnetostrictive part is formed by using a nonmagnetic material for the rotating shaft and forming a metallic glass film on its surface, it is less susceptible to external magnetic fields and, due to the nature of the metallic glass film, The detection characteristics are extremely high (see FIG. 4). That is, as long as a metal glass sprayed coating can be formed, any material rotation shaft can be applied as a torque sensor.
Further, when the amorphous alloy film of the magnetostrictive portion is Fe—Co—Si—B—Nb-based metallic glass, the amorphous forming ability is high, and it is advantageous in terms of magnetic characteristics and mechanical characteristics (FIG. 7A). (See (b) and (c)).
もし回転軸が磁性体であれば、前記のとおり、その表面に螺旋状突起部等を形成するだけで磁歪部が構成でき、わざわざ磁性体の皮膜を設けなくともトルクの検出が可能になる。しかし回転軸が磁性体の場合、それが外部磁界の影響を受けるためにトルクの検出感度が低下する。その点、回転軸に非磁性材料を使用して、その表面に金属ガラス皮膜を形成することにより磁歪部を構成するなら、外部磁界の影響を受けにくいうえに金属ガラス皮膜の特質上、トルクの検出特性がきわめて高くなる(図4参照)。すなわち、金属ガラス溶射皮膜が形成可能であれば、あらゆる材料の回転軸がトルクセンサとして適用可能となる。
また、磁歪部のアモルファス合金皮膜がFe-Co-Si-B-Nb系金属ガラスであると、アモルファス形成能が高いうえ、磁気特性および機械的特性の点でも有利である(図7(a)(b)(c)参照)。 In the above torque sensor, it is more preferable that the rotation axis is a non-magnetic material and the amorphous alloy of the magnetostrictive portion is Fe—Co—Si—B—Nb-based metallic glass.
If the rotating shaft is a magnetic material, as described above, a magnetostrictive portion can be formed simply by forming a helical projection or the like on the surface thereof, and torque can be detected without providing a magnetic film. However, when the rotating shaft is a magnetic material, it is affected by an external magnetic field, so that the torque detection sensitivity decreases. In that respect, if a magnetostrictive part is formed by using a nonmagnetic material for the rotating shaft and forming a metallic glass film on its surface, it is less susceptible to external magnetic fields and, due to the nature of the metallic glass film, The detection characteristics are extremely high (see FIG. 4). That is, as long as a metal glass sprayed coating can be formed, any material rotation shaft can be applied as a torque sensor.
Further, when the amorphous alloy film of the magnetostrictive portion is Fe—Co—Si—B—Nb-based metallic glass, the amorphous forming ability is high, and it is advantageous in terms of magnetic characteristics and mechanical characteristics (FIG. 7A). (See (b) and (c)).
上記のトルクセンサは、上記火炎の温度および上記回転軸の表面温度がそれぞれ一定となるよう管理された状態で、上記の溶射によって回転軸の表面に金属ガラス皮膜が形成されているのが好ましい。
溶射のための火炎は、金属粉末を溶融させるとともに冷却ガスで急速に冷却される必要があるため、その温度は十分に管理される必要がある。しかし発明者らの試験によれば、溶射の際の上記回転軸の表面温度も十分に管理されなければならない。溶射中の回転軸の表面温度によって、その溶射にて構成された磁歪部を含むトルクセンサの感度とヒステリシスが相違することが確認されるからである(図5・図6参照)。感度とヒステリシスに相違が生じるのは、たとえば、当該表面温度が低いと、溶融した金属粉末の回転軸表面に対する密着度が低くなるためにヒステリシスが生じるが、皮膜のアモルファス化率が高くなり、感度は向上する一方、同温度が高いと、密着度が高くなるためにヒステリシスは生じないが、皮膜のアモルファス化率が低くなり、感度は低下すると推測される。したがって、溶射中の回転軸の表面温度は、適切な温度計等によって計測され、適切な温度範囲(300~500℃)に制御される必要がある。 In the above torque sensor, it is preferable that a metal glass film is formed on the surface of the rotating shaft by the thermal spraying in a state where the temperature of the flame and the surface temperature of the rotating shaft are controlled to be constant.
Since the flame for thermal spraying needs to melt the metal powder and be rapidly cooled with a cooling gas, its temperature needs to be sufficiently controlled. However, according to the tests by the inventors, the surface temperature of the rotating shaft during thermal spraying must be sufficiently controlled. This is because it is confirmed that the sensitivity and hysteresis of the torque sensor including the magnetostrictive portion formed by the thermal spraying differ depending on the surface temperature of the rotating shaft during thermal spraying (see FIGS. 5 and 6). The difference between the sensitivity and hysteresis occurs because, for example, if the surface temperature is low, the degree of adhesion of the molten metal powder to the surface of the rotating shaft decreases, so hysteresis occurs, but the film becomes amorphous and the sensitivity increases. On the other hand, if the temperature is high, the degree of adhesion increases and no hysteresis occurs. However, it is presumed that the amorphous ratio of the film decreases and the sensitivity decreases. Therefore, the surface temperature of the rotating shaft during thermal spraying needs to be measured by an appropriate thermometer or the like and controlled to an appropriate temperature range (300 to 500 ° C.).
溶射のための火炎は、金属粉末を溶融させるとともに冷却ガスで急速に冷却される必要があるため、その温度は十分に管理される必要がある。しかし発明者らの試験によれば、溶射の際の上記回転軸の表面温度も十分に管理されなければならない。溶射中の回転軸の表面温度によって、その溶射にて構成された磁歪部を含むトルクセンサの感度とヒステリシスが相違することが確認されるからである(図5・図6参照)。感度とヒステリシスに相違が生じるのは、たとえば、当該表面温度が低いと、溶融した金属粉末の回転軸表面に対する密着度が低くなるためにヒステリシスが生じるが、皮膜のアモルファス化率が高くなり、感度は向上する一方、同温度が高いと、密着度が高くなるためにヒステリシスは生じないが、皮膜のアモルファス化率が低くなり、感度は低下すると推測される。したがって、溶射中の回転軸の表面温度は、適切な温度計等によって計測され、適切な温度範囲(300~500℃)に制御される必要がある。 In the above torque sensor, it is preferable that a metal glass film is formed on the surface of the rotating shaft by the thermal spraying in a state where the temperature of the flame and the surface temperature of the rotating shaft are controlled to be constant.
Since the flame for thermal spraying needs to melt the metal powder and be rapidly cooled with a cooling gas, its temperature needs to be sufficiently controlled. However, according to the tests by the inventors, the surface temperature of the rotating shaft during thermal spraying must be sufficiently controlled. This is because it is confirmed that the sensitivity and hysteresis of the torque sensor including the magnetostrictive portion formed by the thermal spraying differ depending on the surface temperature of the rotating shaft during thermal spraying (see FIGS. 5 and 6). The difference between the sensitivity and hysteresis occurs because, for example, if the surface temperature is low, the degree of adhesion of the molten metal powder to the surface of the rotating shaft decreases, so hysteresis occurs, but the film becomes amorphous and the sensitivity increases. On the other hand, if the temperature is high, the degree of adhesion increases and no hysteresis occurs. However, it is presumed that the amorphous ratio of the film decreases and the sensitivity decreases. Therefore, the surface temperature of the rotating shaft during thermal spraying needs to be measured by an appropriate thermometer or the like and controlled to an appropriate temperature range (300 to 500 ° C.).
トルクセンサの磁歪部については、回転軸表面に凹部と凸部とがそれぞれ線状に交互に配置され、その凹部を埋めるように上記の金属ガラス皮膜が形成されることにより(図10参照)構成されていて、それら凹部および凸部を含む全域に金属ガラス皮膜が形成されたのち研磨されることにより、上記金属ガラス皮膜に隣接する凸部の表面の金属ガラス皮膜がなくなっているものが好ましい。
このような磁歪部は、凹凸を含む回転軸表面に溶射にて広く金属ガラス皮膜を形成し、その後に当該皮膜を研磨する方法によって、比較的簡単に製造することができる。またその場合、凹部に嵌るように金属ガラス皮膜が形成されることになるため、回転軸に対する当該皮膜の一体性がとくに高くなって剥離等しがたく、その一体性に基づいてトルクの検出感度も高いものになる。なお、磁歪部において金属ガラス皮膜の形成部分と不形成の部分とが、回転軸に対して鋭角45度の傾きをもった線状に交互に配置されると、トルクの検出特性が高くなる。 The magnetostrictive portion of the torque sensor has a configuration in which concave portions and convex portions are alternately arranged linearly on the surface of the rotating shaft, and the metal glass film is formed so as to fill the concave portions (see FIG. 10). It is preferable that the metal glass film is formed on the entire region including the concave portions and the convex portions and then polished so that the metal glass film on the surface of the convex portions adjacent to the metal glass film is eliminated.
Such a magnetostrictive part can be relatively easily manufactured by a method in which a metal glass film is widely formed by thermal spraying on the surface of the rotating shaft including irregularities, and then the film is polished. In this case, since the metallic glass film is formed so as to fit in the recess, the film is particularly highly integrated with the rotating shaft and is not easily peeled off. Will also be expensive. In addition, when the portions where the metal glass film is formed and the portions where the metal glass film is not formed are alternately arranged in a line having an acute angle of 45 degrees with respect to the rotation axis in the magnetostrictive portion, the torque detection characteristic is enhanced.
このような磁歪部は、凹凸を含む回転軸表面に溶射にて広く金属ガラス皮膜を形成し、その後に当該皮膜を研磨する方法によって、比較的簡単に製造することができる。またその場合、凹部に嵌るように金属ガラス皮膜が形成されることになるため、回転軸に対する当該皮膜の一体性がとくに高くなって剥離等しがたく、その一体性に基づいてトルクの検出感度も高いものになる。なお、磁歪部において金属ガラス皮膜の形成部分と不形成の部分とが、回転軸に対して鋭角45度の傾きをもった線状に交互に配置されると、トルクの検出特性が高くなる。 The magnetostrictive portion of the torque sensor has a configuration in which concave portions and convex portions are alternately arranged linearly on the surface of the rotating shaft, and the metal glass film is formed so as to fill the concave portions (see FIG. 10). It is preferable that the metal glass film is formed on the entire region including the concave portions and the convex portions and then polished so that the metal glass film on the surface of the convex portions adjacent to the metal glass film is eliminated.
Such a magnetostrictive part can be relatively easily manufactured by a method in which a metal glass film is widely formed by thermal spraying on the surface of the rotating shaft including irregularities, and then the film is polished. In this case, since the metallic glass film is formed so as to fit in the recess, the film is particularly highly integrated with the rotating shaft and is not easily peeled off. Will also be expensive. In addition, when the portions where the metal glass film is formed and the portions where the metal glass film is not formed are alternately arranged in a line having an acute angle of 45 degrees with respect to the rotation axis in the magnetostrictive portion, the torque detection characteristic is enhanced.
トルクセンサの磁歪部は、また、回転軸表面に、金属ガラス皮膜の形成部分と不形成の部分とがそれぞれ線状に交互に配置されることにより(図10参照)構成されていて、磁歪部の全域に金属ガラス皮膜が形成されたのち、回転軸表面の一部をマスクで覆って行うショットブラストにより、上記不形成の部分の金属ガラス皮膜が除去されたものであるのもよい。
このような磁歪部も、溶射と、その後にマスク(上記不形成の部分に対応する位置にスリット等の開口部を有するもの)を磁歪部に被せて行うショットブラストとによって、比較的簡単に構成することができる。なお、除去の方法としては、ショットブラストに限らず、磁歪部に樹脂等を被覆した後にエッチング等の化学処理によるもの、切削等の機械加工によるものでもかまわない。 The magnetostrictive portion of the torque sensor is also configured by alternately arranging the portions where the metallic glass film is formed and the portions where the metallic glass film is not formed on the surface of the rotating shaft (see FIG. 10). After the metal glass film is formed on the entire surface, the non-formed part of the metal glass film may be removed by shot blasting by covering a part of the surface of the rotating shaft with a mask.
Such a magnetostrictive portion is also relatively easily configured by thermal spraying and then shot blasting performed by covering the magnetostrictive portion with a mask (having an opening such as a slit at a position corresponding to the non-formed portion). can do. The removal method is not limited to shot blasting, and may be a chemical process such as etching after the magnetostrictive portion is coated with a resin or a mechanical process such as cutting.
このような磁歪部も、溶射と、その後にマスク(上記不形成の部分に対応する位置にスリット等の開口部を有するもの)を磁歪部に被せて行うショットブラストとによって、比較的簡単に構成することができる。なお、除去の方法としては、ショットブラストに限らず、磁歪部に樹脂等を被覆した後にエッチング等の化学処理によるもの、切削等の機械加工によるものでもかまわない。 The magnetostrictive portion of the torque sensor is also configured by alternately arranging the portions where the metallic glass film is formed and the portions where the metallic glass film is not formed on the surface of the rotating shaft (see FIG. 10). After the metal glass film is formed on the entire surface, the non-formed part of the metal glass film may be removed by shot blasting by covering a part of the surface of the rotating shaft with a mask.
Such a magnetostrictive portion is also relatively easily configured by thermal spraying and then shot blasting performed by covering the magnetostrictive portion with a mask (having an opening such as a slit at a position corresponding to the non-formed portion). can do. The removal method is not limited to shot blasting, and may be a chemical process such as etching after the magnetostrictive portion is coated with a resin or a mechanical process such as cutting.
トルクセンサの磁歪部は、また、回転軸表面に、金属ガラス皮膜の形成部分と不形成の部分とが線状に交互に配置されることにより(図10参照)構成されていて、上記の溶射を、回転軸表面の一部をマスクで覆って行うことにより、上記形成部分の金属ガラス皮膜が形成されたものであるのもよい。
このような磁歪部も、マスク(上記形成部分に対応する位置にスリット等の開口部を有するもの)を磁歪部に被せて行う上記の溶射によって簡単に構成することができる。
トルクセンサの磁歪部は、また、回転軸表面に、金属ガラス皮膜の形成部分と不形成の部分とが線状に交互に配置されることにより構成されていて、上記の溶射を、溶射ガンにより、直接上記形成部分の金属ガラス皮膜が形成されたものであるのもよい。
このような磁歪部も、精密溶射複合機によって簡単に構成することができる。 The magnetostrictive portion of the torque sensor is constructed by alternately arranging the portions where the metal glass film is formed and the portions where the metal glass film is not formed on the surface of the rotating shaft (see FIG. 10). It is also possible that the metal glass film of the above-mentioned formation part is formed by covering a part of the surface of the rotating shaft with a mask.
Such a magnetostrictive portion can also be easily configured by the above-described thermal spraying performed by covering the magnetostrictive portion with a mask (having an opening such as a slit at a position corresponding to the formation portion).
The magnetostrictive portion of the torque sensor is formed by alternately arranging the portions where the metallic glass film is formed and the portions where the metallic glass film is not formed on the surface of the rotating shaft. The metal glass film of the above-mentioned formation part may be directly formed.
Such a magnetostrictive part can also be easily configured by a precision sprayed composite machine.
このような磁歪部も、マスク(上記形成部分に対応する位置にスリット等の開口部を有するもの)を磁歪部に被せて行う上記の溶射によって簡単に構成することができる。
トルクセンサの磁歪部は、また、回転軸表面に、金属ガラス皮膜の形成部分と不形成の部分とが線状に交互に配置されることにより構成されていて、上記の溶射を、溶射ガンにより、直接上記形成部分の金属ガラス皮膜が形成されたものであるのもよい。
このような磁歪部も、精密溶射複合機によって簡単に構成することができる。 The magnetostrictive portion of the torque sensor is constructed by alternately arranging the portions where the metal glass film is formed and the portions where the metal glass film is not formed on the surface of the rotating shaft (see FIG. 10). It is also possible that the metal glass film of the above-mentioned formation part is formed by covering a part of the surface of the rotating shaft with a mask.
Such a magnetostrictive portion can also be easily configured by the above-described thermal spraying performed by covering the magnetostrictive portion with a mask (having an opening such as a slit at a position corresponding to the formation portion).
The magnetostrictive portion of the torque sensor is formed by alternately arranging the portions where the metallic glass film is formed and the portions where the metallic glass film is not formed on the surface of the rotating shaft. The metal glass film of the above-mentioned formation part may be directly formed.
Such a magnetostrictive part can also be easily configured by a precision sprayed composite machine.
上記した発明のトルクセンサは、上記回転軸の表面に上記磁歪部を構成するとき、a)上記回転軸を予熱しておき、b)その表面に、火炎の温度を一定に保った上記の溶射によって上記磁歪部における金属ガラス皮膜を形成することとし、c)当該皮膜の形成の際、上記回転軸を回転させるとともに、上記火炎を回転軸表面に当てることと回転軸表面から逸らすことを繰り返すことによって回転軸表面の温度維持をはかるようにして製造するのがよい。
そのようにすれば、火炎の温度および回転軸の表面温度をそれぞれ一定となるよう管理しながら、上記の溶射によって回転軸の表面に好ましい金属ガラス皮膜を形成できる。回転軸表面に火炎を当て続けると当該表面の温度は上昇し続けるが、上記のように火炎を当てたり逸らしたりすると、回転軸表面の温度を一定範囲内に維持することが可能(図9参照)だからである。こうすることにより、回転軸表面への密着度や一体性にすぐれるうえアモルファス化率も高い金属ガラス皮膜が形成でき、結果として、検出特性に優れたトルクセンサを製造することができる。 The torque sensor according to the invention described above, when the magnetostrictive portion is configured on the surface of the rotating shaft, a) the rotating shaft is preheated, and b) the thermal spray is maintained on the surface with the flame temperature kept constant. To form a metallic glass film on the magnetostrictive portion by c) and repeatedly rotating the rotating shaft and applying the flame to the rotating shaft surface and deflecting from the rotating shaft surface when forming the film. Thus, it is preferable that the temperature is maintained on the surface of the rotating shaft.
By doing so, it is possible to form a preferable metallic glass film on the surface of the rotating shaft by the above thermal spraying while managing the flame temperature and the surface temperature of the rotating shaft to be constant. If the flame is continuously applied to the surface of the rotating shaft, the temperature of the surface continues to rise. However, if the flame is applied or deflected as described above, the temperature of the surface of the rotating shaft can be maintained within a certain range (see FIG. 9). That's why. By doing so, it is possible to form a metal glass film that has excellent adhesion and integrity to the surface of the rotating shaft and a high amorphization rate, and as a result, a torque sensor having excellent detection characteristics can be manufactured.
そのようにすれば、火炎の温度および回転軸の表面温度をそれぞれ一定となるよう管理しながら、上記の溶射によって回転軸の表面に好ましい金属ガラス皮膜を形成できる。回転軸表面に火炎を当て続けると当該表面の温度は上昇し続けるが、上記のように火炎を当てたり逸らしたりすると、回転軸表面の温度を一定範囲内に維持することが可能(図9参照)だからである。こうすることにより、回転軸表面への密着度や一体性にすぐれるうえアモルファス化率も高い金属ガラス皮膜が形成でき、結果として、検出特性に優れたトルクセンサを製造することができる。 The torque sensor according to the invention described above, when the magnetostrictive portion is configured on the surface of the rotating shaft, a) the rotating shaft is preheated, and b) the thermal spray is maintained on the surface with the flame temperature kept constant. To form a metallic glass film on the magnetostrictive portion by c) and repeatedly rotating the rotating shaft and applying the flame to the rotating shaft surface and deflecting from the rotating shaft surface when forming the film. Thus, it is preferable that the temperature is maintained on the surface of the rotating shaft.
By doing so, it is possible to form a preferable metallic glass film on the surface of the rotating shaft by the above thermal spraying while managing the flame temperature and the surface temperature of the rotating shaft to be constant. If the flame is continuously applied to the surface of the rotating shaft, the temperature of the surface continues to rise. However, if the flame is applied or deflected as described above, the temperature of the surface of the rotating shaft can be maintained within a certain range (see FIG. 9). That's why. By doing so, it is possible to form a metal glass film that has excellent adhesion and integrity to the surface of the rotating shaft and a high amorphization rate, and as a result, a torque sensor having excellent detection characteristics can be manufactured.
金属ガラス皮膜を形成する上記の溶射には、結晶質粉末を含む直径40μm以上の金属粉末を使用してもよい。
そのような金属粉末は、より直径の小さいものや非晶質粉末(アモルファス化された粉末)に比べると安価で入手できるため、溶射すなわち磁歪部の構成に要するコストを下げることができる。なお、このような安価な金属粉末を使用できることは、高速フレーム溶射等の高速溶射プロセスとは異なる、本発明特有の利点の一つである。 For the above thermal spraying for forming the metal glass film, a metal powder having a diameter of 40 μm or more including a crystalline powder may be used.
Such a metal powder can be obtained at a lower cost than a powder having a smaller diameter or an amorphous powder (amorphized powder), so that the cost required for thermal spraying, that is, the construction of the magnetostrictive portion can be reduced. The use of such an inexpensive metal powder is one of the advantages unique to the present invention that is different from high-speed spraying processes such as high-speed flame spraying.
そのような金属粉末は、より直径の小さいものや非晶質粉末(アモルファス化された粉末)に比べると安価で入手できるため、溶射すなわち磁歪部の構成に要するコストを下げることができる。なお、このような安価な金属粉末を使用できることは、高速フレーム溶射等の高速溶射プロセスとは異なる、本発明特有の利点の一つである。 For the above thermal spraying for forming the metal glass film, a metal powder having a diameter of 40 μm or more including a crystalline powder may be used.
Such a metal powder can be obtained at a lower cost than a powder having a smaller diameter or an amorphous powder (amorphized powder), so that the cost required for thermal spraying, that is, the construction of the magnetostrictive portion can be reduced. The use of such an inexpensive metal powder is one of the advantages unique to the present invention that is different from high-speed spraying processes such as high-speed flame spraying.
本発明によれば、検出特性にすぐれているほか、磁歪部の構成に要するコストが低くて安価なトルクセンサを提供することができる。
According to the present invention, it is possible to provide an inexpensive torque sensor that is excellent in detection characteristics and low in cost required for the configuration of the magnetostrictive portion.
以下、発明の実施について図面に基づき説明する。
図10のようなトルクセンサにおける回転軸1の一部表面に、溶射により金属ガラス皮膜を形成して図示のような磁歪部A・Bを構成する。各磁歪部A・Bは、軸心方向と45°をなす複数の螺旋状に金属ガラス皮膜を形成し、当該皮膜の形成部分と不形成部分とを交互にそれぞれ線状に配置したものである。磁歪部A・Bの螺旋の向きは互いに異ならせ、双方の線同士が直角をなすようにする。なお、回転軸1の直径は8mm以上、形成部分および不形成部分の螺旋の線幅は1~3mm程度である。 Embodiments of the invention will be described below with reference to the drawings.
Magnetostrictive portions A and B as shown in the figure are formed by forming a metallic glass film on the partial surface of the rotary shaft 1 in the torque sensor as shown in FIG. 10 by thermal spraying. Each of the magnetostrictive portions A and B is formed by forming a metal glass film in a plurality of spiral shapes that form 45 ° with the axial direction, and alternately arranging the formed portions and the non-formed portions of the film. . The directions of the spirals of the magnetostrictive portions A and B are different from each other so that both lines are perpendicular to each other. The diameter of the rotating shaft 1 is 8 mm or more, and the line width of the spiral of the formed part and the non-formed part is about 1 to 3 mm.
図10のようなトルクセンサにおける回転軸1の一部表面に、溶射により金属ガラス皮膜を形成して図示のような磁歪部A・Bを構成する。各磁歪部A・Bは、軸心方向と45°をなす複数の螺旋状に金属ガラス皮膜を形成し、当該皮膜の形成部分と不形成部分とを交互にそれぞれ線状に配置したものである。磁歪部A・Bの螺旋の向きは互いに異ならせ、双方の線同士が直角をなすようにする。なお、回転軸1の直径は8mm以上、形成部分および不形成部分の螺旋の線幅は1~3mm程度である。 Embodiments of the invention will be described below with reference to the drawings.
Magnetostrictive portions A and B as shown in the figure are formed by forming a metallic glass film on the partial surface of the rotary shaft 1 in the torque sensor as shown in FIG. 10 by thermal spraying. Each of the magnetostrictive portions A and B is formed by forming a metal glass film in a plurality of spiral shapes that form 45 ° with the axial direction, and alternately arranging the formed portions and the non-formed portions of the film. . The directions of the spirals of the magnetostrictive portions A and B are different from each other so that both lines are perpendicular to each other. The diameter of the rotating shaft 1 is 8 mm or more, and the line width of the spiral of the formed part and the non-formed part is about 1 to 3 mm.
その磁歪部A・Bにおける金属ガラス皮膜の形成部分と不形成部分とは、つぎの手順で形成する。すなわち、1)回転軸1の表面に複数本の溝を形成して溝付きシャフトとすることにより上記螺旋状の線(形成部分と不形成部分)に沿う凹部と凸部と(図示省略)を交互に設けておき、2)それら凹部と凸部とを含む全域に溶射することによって金属ガラス皮膜を形成し、3)そののち溶射部分を研磨することによって凸部の金属ガラス皮膜を取り除き、4)金属ガラス皮膜(形成部分)の表面とそれに隣接する凸部(不形成部分)の表面との間に段差がない状態にする。
ただし、磁歪部A・Bの構成手順は、上の例に限らず、たとえば、上記のような溝を有しないシャフト(回転軸1)を用い、磁歪部A・Bの全域に溶射によって金属ガラス皮膜を形成したのち、回転軸1の表面の一部をマスク(不形成部分に相当する螺旋状のスリットを有するもの。図示省略)で覆ってショットブラストを行うことにより、金属ガラス皮膜の形成部分と不形成部分とを設けるようにするのもよい。あるいは、上記の溶射を、上記溝のない回転軸表面の一部をマスク(形成部分に相当する螺旋状のスリットを有するもの。図示省略)で覆って行うことにより、同様の形成部分と不形成部分とを設けるのもよい。
基材をショットブラスト後、耐熱塗料等を使ってショブロン状の模様を施し、その表面に溶射皮膜を形成した後に、ショブロン模様上の溶射皮膜のみをグラインダまたはショットブラストを使って除去することで、ショブロンパターンを形成するのもよい。
さらには、基材表面に溶射皮膜を形成した後に、耐ショットブラスト性塗料等を使ってショブロン状のマスキングを施してショットブラスト後、ショブロンパターンを形成するのもよい。 The formation part and the non-formation part of the metallic glass film in the magnetostriction parts A and B are formed by the following procedure. That is, 1) By forming a plurality of grooves on the surface of the rotating shaft 1 to form a grooved shaft, concave and convex portions (not shown) along the spiral line (formed portion and non-formed portion) are formed. 2) Form a metallic glass film by spraying the entire area including the concave and convex portions, and 3) remove the convex metallic glass film by polishing the sprayed portion after that. ) Make sure that there is no step between the surface of the metallic glass film (formation part) and the surface of the convex part (non-formation part) adjacent to it.
However, the configuration procedure of the magnetostrictive portions A and B is not limited to the above example. For example, a metal glass is used by spraying the entire area of the magnetostrictive portions A and B using a shaft (rotary shaft 1) having no groove as described above. After forming the film, a part of the surface of the rotating shaft 1 is covered with a mask (having a spiral slit corresponding to a non-formed part, not shown), and shot blasting is performed, thereby forming a metal glass film forming part. It is also possible to provide a non-formed portion. Alternatively, the above thermal spraying is performed by covering a part of the surface of the rotary shaft without the groove with a mask (having a spiral slit corresponding to the formation portion, not shown), so that the same formation portion and non-formation are formed. A portion may be provided.
After shot blasting the base material, using a heat resistant paint etc. to give a chevron-like pattern, forming a sprayed coating on the surface, by removing only the sprayed coating on the shoblon pattern using a grinder or shot blast, A chevron pattern may be formed.
Further, after forming a sprayed coating on the surface of the base material, it is also possible to form a shoblon pattern after shot blasting by performing a shotblon-like masking using a shot blast resistant paint or the like.
ただし、磁歪部A・Bの構成手順は、上の例に限らず、たとえば、上記のような溝を有しないシャフト(回転軸1)を用い、磁歪部A・Bの全域に溶射によって金属ガラス皮膜を形成したのち、回転軸1の表面の一部をマスク(不形成部分に相当する螺旋状のスリットを有するもの。図示省略)で覆ってショットブラストを行うことにより、金属ガラス皮膜の形成部分と不形成部分とを設けるようにするのもよい。あるいは、上記の溶射を、上記溝のない回転軸表面の一部をマスク(形成部分に相当する螺旋状のスリットを有するもの。図示省略)で覆って行うことにより、同様の形成部分と不形成部分とを設けるのもよい。
基材をショットブラスト後、耐熱塗料等を使ってショブロン状の模様を施し、その表面に溶射皮膜を形成した後に、ショブロン模様上の溶射皮膜のみをグラインダまたはショットブラストを使って除去することで、ショブロンパターンを形成するのもよい。
さらには、基材表面に溶射皮膜を形成した後に、耐ショットブラスト性塗料等を使ってショブロン状のマスキングを施してショットブラスト後、ショブロンパターンを形成するのもよい。 The formation part and the non-formation part of the metallic glass film in the magnetostriction parts A and B are formed by the following procedure. That is, 1) By forming a plurality of grooves on the surface of the rotating shaft 1 to form a grooved shaft, concave and convex portions (not shown) along the spiral line (formed portion and non-formed portion) are formed. 2) Form a metallic glass film by spraying the entire area including the concave and convex portions, and 3) remove the convex metallic glass film by polishing the sprayed portion after that. ) Make sure that there is no step between the surface of the metallic glass film (formation part) and the surface of the convex part (non-formation part) adjacent to it.
However, the configuration procedure of the magnetostrictive portions A and B is not limited to the above example. For example, a metal glass is used by spraying the entire area of the magnetostrictive portions A and B using a shaft (rotary shaft 1) having no groove as described above. After forming the film, a part of the surface of the rotating shaft 1 is covered with a mask (having a spiral slit corresponding to a non-formed part, not shown), and shot blasting is performed, thereby forming a metal glass film forming part. It is also possible to provide a non-formed portion. Alternatively, the above thermal spraying is performed by covering a part of the surface of the rotary shaft without the groove with a mask (having a spiral slit corresponding to the formation portion, not shown), so that the same formation portion and non-formation are formed. A portion may be provided.
After shot blasting the base material, using a heat resistant paint etc. to give a chevron-like pattern, forming a sprayed coating on the surface, by removing only the sprayed coating on the shoblon pattern using a grinder or shot blast, A chevron pattern may be formed.
Further, after forming a sprayed coating on the surface of the base material, it is also possible to form a shoblon pattern after shot blasting by performing a shotblon-like masking using a shot blast resistant paint or the like.
回転軸1に対する金属ガラス皮膜の形成は、図8に示す火炎急冷式の溶射装置11を用い、支持装置(回転軸1を水平に支持して軸心回りに回転させるもの。図示省略)に支持させた回転軸1の外周面に溶射することによって行う。
図示のように溶射装置11は、粉末式フレーム溶射ガン12の前部に、外部冷却装置とも言える二重管の筒状体15等を取り付けたものである。溶射ガン12には、溶射する材料粉末を搬送ガス(たとえば窒素)とともに供給する管と、燃料とするアセチレンおよび酸素の各供給管、ならびに内部冷却ガス(たとえば窒素)の供給管とが接続されている。溶射ガン12の前端にはノズル13があり、それより火炎と溶融材料(上記粉末の溶融したもの)とを噴射する。上記の内部冷却ガスは、ノズル13の周囲に接する位置から吹き出してノズル13の冷却と火炎の温度調節をする。溶射ガン12には、その前端付近であってノズル13の周囲にフランジ状の前部プレート14を固定し、それを介して筒状体15を取り付けている。図示の筒状体15は、溶射ガン12が噴射する火炎Fの前半部分(ノズル13に近い部分。材料粉末の溶融領域)において火炎Fと外気とを隔てるとともに、二重管の先端部より火炎Fの後半部分に冷却ガス(たとえば窒素)Gを吹き出して火炎Fを冷却する。
この溶射装置11は、材料粒子を含む火炎Fをノズル13から噴射し、当該材料粒子を火炎Fによって溶融させたうえ上記冷却ガスGで冷却することにより、回転軸1の表面に金属ガラス皮膜を形成することができる。火炎Fの速度は30~40m/s程度とし、火炎Fの温度は中心部付近が1000~1200℃となるようにする(材料粒子に応じてそれぞれ調整する)。火炎Fは、筒状体15とそれより噴出される冷却ガス(窒素)Gに囲まれて基材10に達するため、金属ガラス皮膜中に酸化物の介在する量を抑制できる。十分な熱量で溶射粒子を溶融させ得ることから、溶射装置11を用いる溶射においては、結晶質粉末を含む直径40μm以上(100μm程度以下)の金属粉末をも使用することが可能である。 The metal glass film is formed on the rotary shaft 1 by using a flame quenching thermal spraying device 11 shown in FIG. 8 and supported by a support device (supporting the rotary shaft 1 horizontally and rotating it around the axis, not shown). This is performed by spraying on the outer peripheral surface of the rotating shaft 1 that has been moved.
As shown in the figure, the thermal spraying device 11 has a double-pipe tubular body 15 or the like that can also be called an external cooling device attached to the front of a powder-typeflame spraying gun 12. Connected to the spray gun 12 are a tube for supplying the material powder to be sprayed together with a carrier gas (for example, nitrogen), a supply tube for acetylene and oxygen as fuel, and a supply tube for an internal cooling gas (for example, nitrogen). Yes. There is a nozzle 13 at the front end of the thermal spray gun 12, from which a flame and a molten material (the melted powder) are sprayed. The internal cooling gas is blown out from a position in contact with the periphery of the nozzle 13 to cool the nozzle 13 and adjust the temperature of the flame. A flange-like front plate 14 is fixed to the thermal spray gun 12 around the nozzle 13 near the front end thereof, and a cylindrical body 15 is attached thereto. The illustrated cylindrical body 15 separates the flame F from the outside air in the first half of the flame F sprayed by the spray gun 12 (portion close to the nozzle 13; the melting region of the material powder), and flame from the tip of the double pipe. Cooling gas (for example, nitrogen) G is blown into the latter half of F to cool the flame F.
The thermal spraying device 11 sprays a flame F containing material particles from anozzle 13, melts the material particles with the flame F, and cools the material particles with the cooling gas G, thereby forming a metallic glass film on the surface of the rotary shaft 1. Can be formed. The speed of the flame F is set to about 30 to 40 m / s, and the temperature of the flame F is set to 1000 to 1200 ° C. near the center (adjusted according to the material particles, respectively). Since the flame F reaches the base material 10 by being surrounded by the cylindrical body 15 and the cooling gas (nitrogen) G ejected therefrom, the amount of oxides in the metal glass film can be suppressed. Since the spray particles can be melted with a sufficient amount of heat, it is possible to use metal powder having a diameter of 40 μm or more (about 100 μm or less) including crystalline powder in the thermal spraying using the thermal spraying apparatus 11.
図示のように溶射装置11は、粉末式フレーム溶射ガン12の前部に、外部冷却装置とも言える二重管の筒状体15等を取り付けたものである。溶射ガン12には、溶射する材料粉末を搬送ガス(たとえば窒素)とともに供給する管と、燃料とするアセチレンおよび酸素の各供給管、ならびに内部冷却ガス(たとえば窒素)の供給管とが接続されている。溶射ガン12の前端にはノズル13があり、それより火炎と溶融材料(上記粉末の溶融したもの)とを噴射する。上記の内部冷却ガスは、ノズル13の周囲に接する位置から吹き出してノズル13の冷却と火炎の温度調節をする。溶射ガン12には、その前端付近であってノズル13の周囲にフランジ状の前部プレート14を固定し、それを介して筒状体15を取り付けている。図示の筒状体15は、溶射ガン12が噴射する火炎Fの前半部分(ノズル13に近い部分。材料粉末の溶融領域)において火炎Fと外気とを隔てるとともに、二重管の先端部より火炎Fの後半部分に冷却ガス(たとえば窒素)Gを吹き出して火炎Fを冷却する。
この溶射装置11は、材料粒子を含む火炎Fをノズル13から噴射し、当該材料粒子を火炎Fによって溶融させたうえ上記冷却ガスGで冷却することにより、回転軸1の表面に金属ガラス皮膜を形成することができる。火炎Fの速度は30~40m/s程度とし、火炎Fの温度は中心部付近が1000~1200℃となるようにする(材料粒子に応じてそれぞれ調整する)。火炎Fは、筒状体15とそれより噴出される冷却ガス(窒素)Gに囲まれて基材10に達するため、金属ガラス皮膜中に酸化物の介在する量を抑制できる。十分な熱量で溶射粒子を溶融させ得ることから、溶射装置11を用いる溶射においては、結晶質粉末を含む直径40μm以上(100μm程度以下)の金属粉末をも使用することが可能である。 The metal glass film is formed on the rotary shaft 1 by using a flame quenching thermal spraying device 11 shown in FIG. 8 and supported by a support device (supporting the rotary shaft 1 horizontally and rotating it around the axis, not shown). This is performed by spraying on the outer peripheral surface of the rotating shaft 1 that has been moved.
As shown in the figure, the thermal spraying device 11 has a double-pipe tubular body 15 or the like that can also be called an external cooling device attached to the front of a powder-type
The thermal spraying device 11 sprays a flame F containing material particles from a
溶射装置11による溶射の際には、火炎Fの温度とともに回転軸1の表面温度が一定となるよう温度管理をする。溶射中の回転軸1の表面温度によっても、その溶射にて構成された磁歪部のトルク検出感度が相違するからである。
回転軸1の表面温度は放射温度計によって計測し、図9のように予熱・降温の各時間t1・t2の間とともに、溶射時間t3において温度コントロールを行う。具体的には、1)予熱時間t1では、溶射開始前にバーナー等によって回転軸1を予熱し、2)やや高めの予熱温度から、溶射材料の飛散を防ぐ邪魔板をセットする間の降温時間t2での多少の降温を確認したうえで溶射を開始し、3)溶射時間t3においては、回転軸1を回転させながら、火炎Fを軸表面に当てることと軸表面から逸らすことを繰り返すことによって回転軸1の表面温度をほぼ一定(300~500℃の範囲内。回転軸1や溶射材料の材質等による)に保つ。つまりこの時間t3の間、水平に支持し回転させる回転軸1(の磁歪部形成箇所)に対し火炎Fを当てながら軸長方向(水平)に送るとともに、その送りの一端または両端で火炎Fを軸長方向と直角な方向(上下いずれかの方向)に往復移動させて軸表面から逸らす。回転軸1が小径であって温度上昇しやすい場合等には、軸表面から逸らした位置で火炎Fをしばらく待機(停止)させることにより表面温度のコントロールを行うようにするのもよい。 At the time of thermal spraying by the thermal spraying device 11, temperature management is performed so that the surface temperature of the rotating shaft 1 becomes constant along with the temperature of the flame F. This is because, depending on the surface temperature of the rotating shaft 1 during thermal spraying, the torque detection sensitivity of the magnetostrictive portion formed by thermal spraying is different.
The surface temperature of the rotating shaft 1 is measured by a radiation thermometer, and temperature control is performed during the spraying time t3 as well as during the preheating / falling time t1 and t2 as shown in FIG. Specifically, 1) At the preheating time t1, the rotating shaft 1 is preheated by a burner or the like before the start of spraying, and 2) the temperature lowering time between setting a baffle plate that prevents the sprayed material from scattering from a slightly higher preheating temperature. After confirming a certain temperature drop at t2, spraying is started. 3) During the spraying time t3, while rotating the rotating shaft 1, by repeatedly applying the flame F to the shaft surface and deflecting it from the shaft surface The surface temperature of the rotating shaft 1 is kept substantially constant (within a range of 300 to 500 ° C., depending on the material of the rotating shaft 1 and the sprayed material). That is, during this time t3, the flame F is applied to the rotating shaft 1 (the magnetostrictive portion forming portion) that is horizontally supported and rotated, and is sent in the axial length direction (horizontal), and the flame F is sent at one or both ends of the feed. Reciprocate in the direction perpendicular to the shaft length direction (either up or down) to deviate from the shaft surface. When the rotating shaft 1 has a small diameter and easily rises in temperature, the surface temperature may be controlled by waiting (stopping) the flame F for a while at a position deviating from the shaft surface.
回転軸1の表面温度は放射温度計によって計測し、図9のように予熱・降温の各時間t1・t2の間とともに、溶射時間t3において温度コントロールを行う。具体的には、1)予熱時間t1では、溶射開始前にバーナー等によって回転軸1を予熱し、2)やや高めの予熱温度から、溶射材料の飛散を防ぐ邪魔板をセットする間の降温時間t2での多少の降温を確認したうえで溶射を開始し、3)溶射時間t3においては、回転軸1を回転させながら、火炎Fを軸表面に当てることと軸表面から逸らすことを繰り返すことによって回転軸1の表面温度をほぼ一定(300~500℃の範囲内。回転軸1や溶射材料の材質等による)に保つ。つまりこの時間t3の間、水平に支持し回転させる回転軸1(の磁歪部形成箇所)に対し火炎Fを当てながら軸長方向(水平)に送るとともに、その送りの一端または両端で火炎Fを軸長方向と直角な方向(上下いずれかの方向)に往復移動させて軸表面から逸らす。回転軸1が小径であって温度上昇しやすい場合等には、軸表面から逸らした位置で火炎Fをしばらく待機(停止)させることにより表面温度のコントロールを行うようにするのもよい。 At the time of thermal spraying by the thermal spraying device 11, temperature management is performed so that the surface temperature of the rotating shaft 1 becomes constant along with the temperature of the flame F. This is because, depending on the surface temperature of the rotating shaft 1 during thermal spraying, the torque detection sensitivity of the magnetostrictive portion formed by thermal spraying is different.
The surface temperature of the rotating shaft 1 is measured by a radiation thermometer, and temperature control is performed during the spraying time t3 as well as during the preheating / falling time t1 and t2 as shown in FIG. Specifically, 1) At the preheating time t1, the rotating shaft 1 is preheated by a burner or the like before the start of spraying, and 2) the temperature lowering time between setting a baffle plate that prevents the sprayed material from scattering from a slightly higher preheating temperature. After confirming a certain temperature drop at t2, spraying is started. 3) During the spraying time t3, while rotating the rotating shaft 1, by repeatedly applying the flame F to the shaft surface and deflecting it from the shaft surface The surface temperature of the rotating shaft 1 is kept substantially constant (within a range of 300 to 500 ° C., depending on the material of the rotating shaft 1 and the sprayed material). That is, during this time t3, the flame F is applied to the rotating shaft 1 (the magnetostrictive portion forming portion) that is horizontally supported and rotated, and is sent in the axial length direction (horizontal), and the flame F is sent at one or both ends of the feed. Reciprocate in the direction perpendicular to the shaft length direction (either up or down) to deviate from the shaft surface. When the rotating shaft 1 has a small diameter and easily rises in temperature, the surface temperature may be controlled by waiting (stopping) the flame F for a while at a position deviating from the shaft surface.
上記溶射によって形成する皮膜は、たとえばFe-Co-Si-B-Nb系金属ガラスとするのがよい。その金属ガラスは、図7(a)~(c)に示すように、アモルファス形成能が高くてアモルファス化させやすいうえ、磁気特性にすぐれ、また機械的特性においては塑性変形しがたい、といった点で好ましいからである。すなわち、まず図7(a)は、一例として
(Fe1-xCox)72B20Si4Nb4の金属ガラスにおける磁歪(λs)および保持力(Hc)をCoの濃度ごとに調べた線図であり、いずれの特性にもすぐれることが分かる。図7(b)は、同じ金属ガラスについて同様に機械的特性を調査したもので、圧縮強度、ヤング率、塑性伸びについて良好な特性を有するといえる。また、図7(c)は、(Fe0.5Co0.5)72Si4B20Nb4金属ガラスについて、前述した急冷溶射(図8の溶射装置11を使用)を行って得た溶射膜のXRDプロファイルを示す。溶射条件を変えて得た2種類の溶射膜のいずれにおいてもアモルファス相のみが得られており、組織的には溶射で容易にアモルファス相が得られる合金であることが判明した。
なお、回転軸1の材質は問わないが、チタンやステンレス鋼等の非磁性体とするのが有利である。回転軸1が非磁性体であれば、外部磁界の影響を受けにくく、したがってトルク検出特性が高くなるからである。 The coating formed by thermal spraying is preferably made of, for example, Fe—Co—Si—B—Nb-based metallic glass. As shown in FIGS. 7 (a) to (c), the metal glass has high amorphous forming ability and is easy to be made amorphous, has excellent magnetic properties, and is difficult to be plastically deformed in mechanical properties. This is because it is preferable. That is, first, FIG. 7A is an example.
(Fe 1-x Co x ) 72 B 20 Si 4 Nb 4 is a diagram showing magnetostriction (λs) and coercive force (Hc) in Co glass for each concentration of metal, with excellent properties. I understand. FIG. 7 (b) is an investigation of the mechanical properties of the same metallic glass in the same manner, and it can be said that it has good properties in terms of compressive strength, Young's modulus, and plastic elongation. FIG. 7C shows an XRD profile of a sprayed film obtained by performing the aforementioned rapid thermal spraying (using the thermal spraying apparatus 11 of FIG. 8) on (Fe 0.5 Co 0.5 ) 72 Si 4 B 20 Nb 4 metallic glass. Indicates. Only the amorphous phase was obtained in any of the two types of sprayed films obtained by changing the spraying conditions, and it was structurally found that the alloy can be easily obtained by spraying.
In addition, although the material of the rotating shaft 1 is not ask | required, it is advantageous to set it as nonmagnetic materials, such as titanium and stainless steel. This is because if the rotating shaft 1 is a non-magnetic material, it is not easily affected by an external magnetic field, and therefore torque detection characteristics are improved.
(Fe1-xCox)72B20Si4Nb4の金属ガラスにおける磁歪(λs)および保持力(Hc)をCoの濃度ごとに調べた線図であり、いずれの特性にもすぐれることが分かる。図7(b)は、同じ金属ガラスについて同様に機械的特性を調査したもので、圧縮強度、ヤング率、塑性伸びについて良好な特性を有するといえる。また、図7(c)は、(Fe0.5Co0.5)72Si4B20Nb4金属ガラスについて、前述した急冷溶射(図8の溶射装置11を使用)を行って得た溶射膜のXRDプロファイルを示す。溶射条件を変えて得た2種類の溶射膜のいずれにおいてもアモルファス相のみが得られており、組織的には溶射で容易にアモルファス相が得られる合金であることが判明した。
なお、回転軸1の材質は問わないが、チタンやステンレス鋼等の非磁性体とするのが有利である。回転軸1が非磁性体であれば、外部磁界の影響を受けにくく、したがってトルク検出特性が高くなるからである。 The coating formed by thermal spraying is preferably made of, for example, Fe—Co—Si—B—Nb-based metallic glass. As shown in FIGS. 7 (a) to (c), the metal glass has high amorphous forming ability and is easy to be made amorphous, has excellent magnetic properties, and is difficult to be plastically deformed in mechanical properties. This is because it is preferable. That is, first, FIG. 7A is an example.
(Fe 1-x Co x ) 72 B 20 Si 4 Nb 4 is a diagram showing magnetostriction (λs) and coercive force (Hc) in Co glass for each concentration of metal, with excellent properties. I understand. FIG. 7 (b) is an investigation of the mechanical properties of the same metallic glass in the same manner, and it can be said that it has good properties in terms of compressive strength, Young's modulus, and plastic elongation. FIG. 7C shows an XRD profile of a sprayed film obtained by performing the aforementioned rapid thermal spraying (using the thermal spraying apparatus 11 of FIG. 8) on (Fe 0.5 Co 0.5 ) 72 Si 4 B 20 Nb 4 metallic glass. Indicates. Only the amorphous phase was obtained in any of the two types of sprayed films obtained by changing the spraying conditions, and it was structurally found that the alloy can be easily obtained by spraying.
In addition, although the material of the rotating shaft 1 is not ask | required, it is advantageous to set it as nonmagnetic materials, such as titanium and stainless steel. This is because if the rotating shaft 1 is a non-magnetic material, it is not easily affected by an external magnetic field, and therefore torque detection characteristics are improved.
以上のようにして磁歪部を構成した発明のトルクセンサにおけるトルク検出特性について、各種の比較データを得たので以下に紹介する。
As described above, various comparative data on the torque detection characteristics of the torque sensor of the invention having the magnetostrictive portion as described above have been obtained.
まず図1に、炭素鋼(SK3)製の回転軸に上記とおり金属ガラスを溶射して前述の磁歪部とした場合と、金属ガラスを使用せず、炭素鋼(SK3)製の回転軸の表面に螺旋状に延びた凹凸のみを形成して磁歪部とした場合とについて、トルク(横軸)とセンサ出力(縦軸)との関係を示している。前者の例では、前記した溝付きシャフトを利用して磁歪部に金属ガラスの形成部分と不形成部分とを設けている。
磁歪部に金属ガラス皮膜を有する前者の場合は、当該皮膜を有しない後者の例に比べると、直線性はやや劣るものの感度がきわめて高いことが分かる。これほどまでに感度が高いと、アンプによって出力を増幅する必要がなく、そのためにノイズが少ない(ノイズフィルターが不要になる)という利点がある。 First, the surface of the rotating shaft made of carbon steel (SK3) without using metallic glass is shown in Fig. 1 when the metallic glass is sprayed onto the rotating shaft made of carbon steel (SK3) as described above. The relationship between the torque (horizontal axis) and the sensor output (vertical axis) is shown for the case where only the irregularities extending spirally are formed to form a magnetostrictive portion. In the former example, a metal glass forming portion and a non-forming portion are provided in the magnetostrictive portion using the grooved shaft described above.
It can be seen that the former having a metallic glass film in the magnetostrictive part has a very high sensitivity although the linearity is somewhat inferior to the latter example having no film. When the sensitivity is so high, there is an advantage that the output does not need to be amplified by an amplifier, and therefore there is less noise (no noise filter is required).
磁歪部に金属ガラス皮膜を有する前者の場合は、当該皮膜を有しない後者の例に比べると、直線性はやや劣るものの感度がきわめて高いことが分かる。これほどまでに感度が高いと、アンプによって出力を増幅する必要がなく、そのためにノイズが少ない(ノイズフィルターが不要になる)という利点がある。 First, the surface of the rotating shaft made of carbon steel (SK3) without using metallic glass is shown in Fig. 1 when the metallic glass is sprayed onto the rotating shaft made of carbon steel (SK3) as described above. The relationship between the torque (horizontal axis) and the sensor output (vertical axis) is shown for the case where only the irregularities extending spirally are formed to form a magnetostrictive portion. In the former example, a metal glass forming portion and a non-forming portion are provided in the magnetostrictive portion using the grooved shaft described above.
It can be seen that the former having a metallic glass film in the magnetostrictive part has a very high sensitivity although the linearity is somewhat inferior to the latter example having no film. When the sensitivity is so high, there is an advantage that the output does not need to be amplified by an amplifier, and therefore there is less noise (no noise filter is required).
つづく図2には、回転軸に上記のとおり金属ガラスを溶射して磁歪部とした場合と、単ロール法で形成したアモルファスリボンを回転軸の表面に貼り付けて磁歪部とした場合とについて、トルクとセンサ出力との関係を示す。回転軸は双方とも炭素鋼(SK3)である。前者では、前記の溝付きシャフトを利用して磁歪部に金属ガラスの形成部分と不形成部分とを設けている。前者の金属ガラスの厚みは140~150μm、後者のアモルファスリボンの厚みは25μm(溝のない回転軸表面に貼り付けている)である。
アモルファスリボンを貼り付けた後者の例では、リボンと回転軸との密着性が十分でないせいか、溶射によって金属ガラス皮膜を形成した前者に比べてヒステリシスを発生させやすいことが分かる。 In FIG. 2, the case where the metal glass is sprayed on the rotating shaft as described above to form a magnetostrictive portion and the case where an amorphous ribbon formed by a single roll method is attached to the surface of the rotating shaft to form a magnetostrictive portion. The relationship between torque and sensor output is shown. Both rotating shafts are carbon steel (SK3). In the former, the magnetostrictive portion is provided with a metal glass forming portion and a non-forming portion using the grooved shaft. The thickness of the former metallic glass is 140 to 150 μm, and the thickness of the latter amorphous ribbon is 25 μm (attached to the surface of the rotating shaft without grooves).
In the latter example in which an amorphous ribbon is pasted, it can be seen that hysteresis is more likely to occur than the former in which a metallic glass film is formed by thermal spraying because the adhesion between the ribbon and the rotating shaft is not sufficient.
アモルファスリボンを貼り付けた後者の例では、リボンと回転軸との密着性が十分でないせいか、溶射によって金属ガラス皮膜を形成した前者に比べてヒステリシスを発生させやすいことが分かる。 In FIG. 2, the case where the metal glass is sprayed on the rotating shaft as described above to form a magnetostrictive portion and the case where an amorphous ribbon formed by a single roll method is attached to the surface of the rotating shaft to form a magnetostrictive portion. The relationship between torque and sensor output is shown. Both rotating shafts are carbon steel (SK3). In the former, the magnetostrictive portion is provided with a metal glass forming portion and a non-forming portion using the grooved shaft. The thickness of the former metallic glass is 140 to 150 μm, and the thickness of the latter amorphous ribbon is 25 μm (attached to the surface of the rotating shaft without grooves).
In the latter example in which an amorphous ribbon is pasted, it can be seen that hysteresis is more likely to occur than the former in which a metallic glass film is formed by thermal spraying because the adhesion between the ribbon and the rotating shaft is not sufficient.
図3には、磁歪部の金属ガラス皮膜を、上記の溶射によって形成した場合と、高速フレーム溶射(HVOF)によって形成した場合とについて、トルクとセンサ出力との関係を示している。回転軸はいずれも炭素鋼(SK3)製であり、金属ガラスはいずれも、前記のとおり(Fe0.5Co0.5)72Si4B20Nb4である。
HVOFによるものは出力の直線性にはすぐれているが、感度が低くヒステリシスを生じるといえる。HVOFでは、粉末材料の溶け込みが十分でないことから回転軸の表面との密着性が高くないのではないかと推察される。 FIG. 3 shows the relationship between torque and sensor output when the metallic glass film of the magnetostrictive part is formed by the above-mentioned thermal spraying and when it is formed by high-speed flame spraying (HVOF). The rotating shafts are all made of carbon steel (SK3), and the metallic glasses are all (Fe 0.5 Co 0.5 ) 72 Si 4 B 20 Nb 4 as described above.
Although HVOF is excellent in output linearity, it can be said that the sensitivity is low and hysteresis occurs. In HVOF, since the powder material is not sufficiently dissolved, it is assumed that the adhesion to the surface of the rotating shaft is not high.
HVOFによるものは出力の直線性にはすぐれているが、感度が低くヒステリシスを生じるといえる。HVOFでは、粉末材料の溶け込みが十分でないことから回転軸の表面との密着性が高くないのではないかと推察される。 FIG. 3 shows the relationship between torque and sensor output when the metallic glass film of the magnetostrictive part is formed by the above-mentioned thermal spraying and when it is formed by high-speed flame spraying (HVOF). The rotating shafts are all made of carbon steel (SK3), and the metallic glasses are all (Fe 0.5 Co 0.5 ) 72 Si 4 B 20 Nb 4 as described above.
Although HVOF is excellent in output linearity, it can be said that the sensitivity is low and hysteresis occurs. In HVOF, since the powder material is not sufficiently dissolved, it is assumed that the adhesion to the surface of the rotating shaft is not high.
図4は、チタン(Ti-6Al-4V)製および炭素鋼(S45C)製の各回転軸に、図8の装置11による上記の溶射を行って磁歪部を構成した場合について、トルクとセンサ出力との関係を示している。いずれの場合も、磁歪部には、前記の溝付きシャフトを利用して金属ガラスの形成部分と不形成部分とを設けている。金属ガラス皮膜の厚みに差はない。
この図4によると、回転軸をチタン製にすると、炭素鋼製である場合に比べて直線性はやや劣るものの感度において大幅にすぐれることが分かる。これは、チタン材が鉄材に比して、弾性率が低く歪量が大きいことに加え、非磁性であるため、コイルのつくる磁束を磁歪部に集中させやすいという特徴を持つためである。 FIG. 4 shows the torque and sensor output in the case where the magnetostriction portion is formed by performing the above-described thermal spraying by the apparatus 11 of FIG. 8 on each of the rotating shafts made of titanium (Ti-6Al-4V) and carbon steel (S45C). Shows the relationship. In either case, the magnetostrictive portion is provided with a metal glass forming portion and a non-forming portion using the grooved shaft. There is no difference in the thickness of the metallic glass film.
According to FIG. 4, it can be seen that when the rotating shaft is made of titanium, the linearity is slightly inferior to that of carbon steel, but the sensitivity is greatly improved. This is because the titanium material has a characteristic that it is easy to concentrate the magnetic flux produced by the coil on the magnetostrictive portion because the titanium material has a low elastic modulus and a large amount of strain as compared with the iron material and is non-magnetic.
この図4によると、回転軸をチタン製にすると、炭素鋼製である場合に比べて直線性はやや劣るものの感度において大幅にすぐれることが分かる。これは、チタン材が鉄材に比して、弾性率が低く歪量が大きいことに加え、非磁性であるため、コイルのつくる磁束を磁歪部に集中させやすいという特徴を持つためである。 FIG. 4 shows the torque and sensor output in the case where the magnetostriction portion is formed by performing the above-described thermal spraying by the apparatus 11 of FIG. 8 on each of the rotating shafts made of titanium (Ti-6Al-4V) and carbon steel (S45C). Shows the relationship. In either case, the magnetostrictive portion is provided with a metal glass forming portion and a non-forming portion using the grooved shaft. There is no difference in the thickness of the metallic glass film.
According to FIG. 4, it can be seen that when the rotating shaft is made of titanium, the linearity is slightly inferior to that of carbon steel, but the sensitivity is greatly improved. This is because the titanium material has a characteristic that it is easy to concentrate the magnetic flux produced by the coil on the magnetostrictive portion because the titanium material has a low elastic modulus and a large amount of strain as compared with the iron material and is non-magnetic.
また、図5および図6には、センサ出力に及ぼす溶射温度の影響について示している。つまり、金属ガラス皮膜を形成する際の磁歪部での回転軸表面の温度(図9に示す溶射時間t3での低部温度)が、トルクとセンサ出力との関係にどのような影響をもたらすかを表している。図5は、前記の直径30mmの螺旋状溝付きシャフトを利用して磁歪部に金属ガラスの形成部分と不形成部分とを設けた例で、図6は、直径30mmシャフトの回転軸に対し、磁歪部の全域に溶射したのち前記のようにマスキングしてショットブラストを行うことにより金属ガラス皮膜の形成部分と不形成部分とを設けた例である。いずれのケースでも、回転軸の表面温度は、前述のとおり放射温度計で計測した。なお、図5と図6のそれぞれにおいて、温度計測のための放射率は別個に設定している。
図5・図6によれば、溶射中の回転軸表面の温度によって、トルクセンサの感度や直線性の相違が生じることが確認される。当該温度によって、回転軸表面に対する溶融金属の密着度や溶射皮膜のアモルファス化率が変わるためであると推測される。試験によると、当該温度の最適値は300~500℃の範囲内にあるが、回転軸や溶射皮膜の材質、あるいは、溶射部の形状や大きさによって最適な温度が異なる。 5 and 6 show the influence of the spraying temperature on the sensor output. In other words, what effect does the temperature of the surface of the rotating shaft at the magnetostrictive part (low temperature at the spraying time t3 shown in FIG. 9) have on the relationship between torque and sensor output when forming the metallic glass film? Represents. FIG. 5 is an example in which the magnetostrictive portion is provided with a metallic glass forming portion and a non-forming portion using the spiral grooved shaft having a diameter of 30 mm, and FIG. This is an example in which the formation portion and the non-formation portion of the metal glass film are provided by performing spray blasting after performing thermal spraying on the entire area of the magnetostrictive portion and performing shot blasting as described above. In any case, the surface temperature of the rotating shaft was measured with a radiation thermometer as described above. In addition, in each of FIG. 5 and FIG. 6, the emissivity for temperature measurement is set separately.
5 and 6, it is confirmed that the sensitivity and linearity of the torque sensor vary depending on the temperature of the surface of the rotating shaft during thermal spraying. This is presumably because the degree of adhesion of the molten metal to the surface of the rotating shaft and the amorphization rate of the sprayed coating change depending on the temperature. According to the test, the optimum value of the temperature is in the range of 300 to 500 ° C., but the optimum temperature varies depending on the rotating shaft, the material of the sprayed coating, and the shape and size of the sprayed portion.
図5・図6によれば、溶射中の回転軸表面の温度によって、トルクセンサの感度や直線性の相違が生じることが確認される。当該温度によって、回転軸表面に対する溶融金属の密着度や溶射皮膜のアモルファス化率が変わるためであると推測される。試験によると、当該温度の最適値は300~500℃の範囲内にあるが、回転軸や溶射皮膜の材質、あるいは、溶射部の形状や大きさによって最適な温度が異なる。 5 and 6 show the influence of the spraying temperature on the sensor output. In other words, what effect does the temperature of the surface of the rotating shaft at the magnetostrictive part (low temperature at the spraying time t3 shown in FIG. 9) have on the relationship between torque and sensor output when forming the metallic glass film? Represents. FIG. 5 is an example in which the magnetostrictive portion is provided with a metallic glass forming portion and a non-forming portion using the spiral grooved shaft having a diameter of 30 mm, and FIG. This is an example in which the formation portion and the non-formation portion of the metal glass film are provided by performing spray blasting after performing thermal spraying on the entire area of the magnetostrictive portion and performing shot blasting as described above. In any case, the surface temperature of the rotating shaft was measured with a radiation thermometer as described above. In addition, in each of FIG. 5 and FIG. 6, the emissivity for temperature measurement is set separately.
5 and 6, it is confirmed that the sensitivity and linearity of the torque sensor vary depending on the temperature of the surface of the rotating shaft during thermal spraying. This is presumably because the degree of adhesion of the molten metal to the surface of the rotating shaft and the amorphization rate of the sprayed coating change depending on the temperature. According to the test, the optimum value of the temperature is in the range of 300 to 500 ° C., but the optimum temperature varies depending on the rotating shaft, the material of the sprayed coating, and the shape and size of the sprayed portion.
以上のように、本発明にしたがって磁歪部を構成したトルクセンサは、溶射の際の火炎や回転軸表面の温度を適切にコントロールするなら、他の方法や材質・形態を採用したトルクセンサよりも好ましいトルク検出特性を発揮し得ることが分かる。
As described above, the torque sensor having the magnetostrictive portion according to the present invention is more suitable than the torque sensor adopting other methods, materials, and forms as long as the flame and the temperature of the rotating shaft surface during spraying are appropriately controlled. It can be seen that preferable torque detection characteristics can be exhibited.
1 回転軸
A・B 磁歪部
11 溶射装置 1 Rotating shaft A / B Magnetostrictive part 11 Thermal spraying device
A・B 磁歪部
11 溶射装置 1 Rotating shaft A / B Magnetostrictive part 11 Thermal spraying device
Claims (7)
- 回転軸の表面に、金属ガラス皮膜を含む磁歪部を有するトルクセンサであって、
上記磁歪部における金属ガラス皮膜が、金属粉末を含む火炎を噴射して金属粉末を溶融させるとともに、当該火炎を、それが回転軸表面に達する前より外側からの冷却ガスにて冷却する方式の溶射によって上記回転軸の表面に形成されていることを特徴とするトルクセンサ。 A torque sensor having a magnetostrictive portion including a metallic glass film on the surface of the rotating shaft,
The metal glass coating in the magnetostrictive part sprays a flame containing metal powder to melt the metal powder and cools the flame with a cooling gas from outside before it reaches the surface of the rotating shaft. The torque sensor is formed on the surface of the rotating shaft. - 上記回転軸が非磁性体であり、上記磁歪部の金属ガラスがFe-Co-Si-B-Nb系金属ガラスであることを特徴とする請求項1に記載のトルクセンサ。 The torque sensor according to claim 1, wherein the rotating shaft is a non-magnetic material, and the metal glass of the magnetostrictive portion is Fe-Co-Si-B-Nb-based metal glass.
- 回転軸表面に凹部と凸部とがそれぞれ線状に交互に配置されたうえその凹部を埋めるように上記金属ガラス皮膜が形成されることにより上記の磁歪部が構成されていて、当該磁歪部は、凹部および凸部を含む全域に金属ガラス皮膜が形成されたのち研磨されることにより、上記金属ガラス皮膜とそれに隣接する凸部の表面の金属ガラス皮膜がなくなっていることを特徴とする請求項1または2に記載のトルクセンサ。 The magnetostrictive portion is formed by forming the metal glass film so that the concave portions and the convex portions are alternately arranged linearly on the surface of the rotating shaft and filling the concave portions. The metal glass film is formed on the entire surface including the concave and convex portions and then polished, whereby the metal glass film on the surface of the metal glass film and the convex portions adjacent thereto is eliminated. The torque sensor according to 1 or 2.
- 回転軸表面に、金属ガラス皮膜の形成部分と不形成の部分とがそれぞれ螺旋状に交互に配置されることにより上記の磁歪部が構成されていて、当該磁歪部は、全域に金属ガラス皮膜が形成されたのち、皮膜表面の一部をマスクで覆って行うショットブラストかエッチング等の化学処理または切削等の機械加工により、上記不形成の部分の金属ガラス皮膜が除去されたものであることを特徴とする請求項1または2に記載のトルクセンサ。 The magnetostrictive portion is formed by alternately arranging the formed portion and the non-formed portion of the metallic glass film on the surface of the rotating shaft, and the magnetostrictive portion has the metallic glass film over the entire area. After the formation, the non-formed portion of the metallic glass film is removed by chemical processing such as shot blasting or etching performed by covering a part of the film surface with a mask or machining such as cutting. The torque sensor according to claim 1 or 2, characterized in that
- 回転軸表面に、金属ガラス皮膜の形成部分と不形成の部分とがそれぞれ線状に交互に配置されることにより上記の磁歪部が構成されていて、当該磁歪部は、上記の溶射を回転軸表面の一部をマスクで覆って行うことにより、上記形成部分の金属ガラス皮膜が形成されたものであることを特徴とする請求項1または2に記載のトルクセンサ。 The magnetostrictive portion is configured by alternately arranging the portions where the metal glass film is formed and the portions where the metallic glass film is not formed on the surface of the rotational shaft, and the magnetostrictive portion rotates the thermal spray on the rotational axis. The torque sensor according to claim 1 or 2, wherein a part of the surface is covered with a mask to form a metal glass film of the formation part.
- 請求項1~5のいずれかに記載したトルクセンサの製造方法であって、上記回転軸の表面に上記磁歪部を構成するとき、
上記回転軸を予熱しておき、その表面に、火炎の温度を一定に保った上記の溶射によって上記磁歪部における金属ガラス皮膜を形成することとし、当該皮膜の形成の際、上記回転軸を回転させるとともに、上記火炎を回転軸表面に当てることと回転軸表面から逸らすことを繰り返すことによって回転軸表面の温度維持をはかることを特徴とするトルクセンサの製造方法。 The torque sensor manufacturing method according to any one of claims 1 to 5, wherein the magnetostrictive portion is formed on the surface of the rotating shaft.
The rotating shaft is preheated, and the metal glass film on the magnetostrictive portion is formed on the surface by the thermal spraying with the flame temperature kept constant, and the rotating shaft is rotated when the coating is formed. And the temperature of the surface of the rotating shaft is maintained by repeatedly applying the flame to the surface of the rotating shaft and deflecting it from the surface of the rotating shaft. - 金属ガラス皮膜を形成する上記の溶射に、結晶質粉末を含む直径40μm以上の金属粉末を使用することを特徴とする請求項6に記載したトルクセンサの製造方法。 7. The method of manufacturing a torque sensor according to claim 6, wherein a metal powder having a diameter of 40 μm or more including a crystalline powder is used for the thermal spraying for forming the metal glass film.
Priority Applications (1)
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JP2014219259A (en) * | 2013-05-08 | 2014-11-20 | 旭化成建材株式会社 | Rotation torque measuring device |
WO2016185785A1 (en) * | 2015-05-21 | 2016-11-24 | 株式会社中山アモルファス | Facility and method for manufacturing torque sensor shaft |
WO2019088149A1 (en) * | 2017-11-01 | 2019-05-09 | 臼井国際産業株式会社 | Stick-on label, label adhering method, method for manufacturing torque sensor shaft, and facility for manufacturing same |
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JP7032106B2 (en) | 2017-11-01 | 2022-03-08 | 臼井国際産業株式会社 | Label for sticking, label sticking method, torque sensor shaft manufacturing method and shaft manufacturing equipment |
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