1993年に実施した急性動物実験で得られた経験に基づいて, リニアモータの推力向上と血液ポンプの流入口の径を大きくしたリニアモータ駆動型全人工心臓(リニアTAH)を試作した。模擬循環試験装置を用いてリニアTAHの効率を測定した結果, ポンプ拍動数120[bpm]において, 入力電力30、18[W], 機械出力2.03[W]であり, 効率は6.7%であった。リニアTAHの損失のうち, 鉄損が19.4[W]であった。羊を用いた急性動物実験において, ポンプ拍動数が85[bpm]の時, 量大左心ポンプ拍出量4.2[Llmin]が得られた。ポンプ拍動数60～100[bpm]の範囲内において, 左右流量差は0～9.1%であった。2時間の循環代行後のリニアモータの表面温度は49[℃]まで上昇した。

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リニアモータ駆動型全人工心臓(TAH)を試作し, 羊を用いた急性動物実験による性能評価を実施した。TAHの拍動数(流量)を変化させて血行動態を測定し, 2時間の循環代行を行った。しかし, 急性動物実験における下行大動脈流量は, mock試験で得られた流量特性4.8[L/min]からの予想に反して, control dataの3.1[L/min]の約50%, すなわち1.5[L/min]しか得られなかった。今後, より長時間の循環代行を実現するためには, 送血カニューレの流体抵抗の減少, およびリニアモータのより一層の推力増加が必要であるということが明らかとなった。また, これらの知見に基づいて改良を加えたリニアモータ駆動型TAHを新たに試作し, その基本的な特性について述べた。

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Linear induction motors (hereafter, referred to as LIM) have large start-up thrust, and can be accelerated or retarded largely. The system can be made into light weight, accordingly, the maintenance becomes easy.
Also they have advantages such as low noise, and are used for the purpose requiring long stroke function from medium speed to high speed.
Thus, they contribute largely to industries.
As the range of their application expands hereafter, not only the one-dimensional drive but also the demand for those which enables the two-dimensional drive will increase. However at present, the device which realized the two-dimensional drive with only one LIM has not been found as far as the authors knows, and the only method is to use by combining several existing LIMs. But by the method like this, since the mechanism is complicated, the control and maintenance are relatively troublesome.
For the purpose of improving the point described above, the authors made the device generating thrust simultaneously in bi-directions (hereafter, referred to as bi-directional LIM) for trial, and carried out the fundamental experiment, therefore, it is reported in this paper.
Besides, in the bi-directional LIM, the primary windings are arranged on an iron core along two horizontal, perpendicularly intersecting axes as shown in Figures 1, and two-dimensional moving magnetic field is generated, thus, it can drive the moving part in any direction.
As the applications, the part selecting carrying direction at the branching point in transport, the part selecting recovering direction in non-ferrous metal recovery facility and the device giving motion in any direction as a no-contact electromagnetic shuttle seem to be feasible.

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1．LDIAの成り立ち　産業用リニアドライブ国際シンポジウム (International Symposium on Linear Drives for Industry Applications： LDIA) は，産業応用部門主催でスタートした日本発祥の国際シンポジウムであり，リニアモータ，リニアアクチュエータ，磁気浮上などの技術とそれらの産業応用

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Stacked three-phase three-limbed model transformer core has been assembled from POWERCORE strip sheet and the localized rotational flux distributions and distortion factors are measured using arrays of cross-type search coils. In the studies of two-dimensional magnetic properties for amorphous magnetic materials, we have reported that a remarkable anisotropy was observed under high magnetic flux density conditions. Therefore, it is necessary to make clear the influence of the anisotropy to the flux distributions at the T-joint part in the threephase transformer core. In this paper, the rotational flux distributions in the amorphous transformer core are investigated by using the three-phase threelimbed model core assembled POWERCORE strip.

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The electrical and mechanical time constants of the linear dc motor (LDM) are required to be small so as to achieve a high-speed response. This paper describes a design method of the magnetic circuit and the electrical and mechanical time constants on a moving-magnet-type LDM. The following results are obtained:
(1) Design a high-speed-response moving magnet type LDM using the expressions of the electrical and mechanical time constants.
(2) In the LDM designed using this approach mechanical time constant is 1.9 ms and erectrical time constant is 5.4 ms. Moreover the calculation by FEM mechanical time constant is 2.0 ms and erectrical time constant is 4.6 ms, and the differences with a pemeance method are 5 % and 17 % grade, respectively. Therefore, this design approach using the pemeance method is useful as means to calculate characteristics of LDM as compared with the calculation approaches, such as FEM, though it is simple.

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筆者らは, リニアパルスモータを人工心臓用アクチュエータとして基礎研究を続けてきた。今回, 試作したリニアパルスモータ(LPM-S90)の両側にそれぞれ血液ポンプを取り付けた両心式人工心臓を開発した。リニアパルスモータは, 2相励磁, 2(A)において107(N)の静推力を発生し, 65(N)の動推力を得た。本両心式人工心臓は体積520(mL), 質量1.2(kg)であり, 一回拍出量は60(mL)である。また, 人工弁にはオムニカーボン弁を用いている。本人工心臓の模擬循環試験の結果, 拍動数100(bpm), 大動脈圧80(mmHg)において5.3～5.7(L/min)の分時流量が得られた。

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The authors have been considering to use a linear pulse motor (LPM) as a driving source of a totally implantable artificial heart (TAH), and have developed a series of artificial heart models that incorporate such a motor. The newly developed linear-type TAH (linear TAH) has two blood pumps, which are inflated and deflated alternately by the LPM, causing a pusher plate to pulsate the blood.
This paper deals with the performance calculation of the LPM using the loading ratio. Then some motors manufactured for driving TAHs were selected to compare their machine parameters. The selected motors were LPMs, linear oscillatory actuator, brushless dc motors, and ultrasonic motor. Two parameters were selected for the comparison: the mechanical output/volume ratio and the motor constant. The results may be summarized as follows:
1. the LPM was designed based on the loading ratio, and the kinetic thrust and velocity were obtained at the range of 77 newtons, 80mm/s respectively;
2. the loading ratio of the LPMs were more than eight times larger in comparison with the rotary motors which were used in industrial machines;
3. the motor constants of the LPMs were recognized one figure larger than that of the bnrshless dc motors.
In order to reduce the volume of the linear TAN, it is necessary to increase the drive velocity of the LPMs. Application of the linear motor to a nonpulsatile artificial heart will be one way to achieve this.

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The purpose of this work is to clarify the correlation between magnetic reluctance distribution and structural parameters in linear pulse motor (LPM). By clarifying correlation between them, we can control magnetic characteristics of LPM and adapt them to applications. In this paper, we show as follows:
(1) We discuss the correlation between harmonic of gap reluctance and structural parameters in LPM by using multiple regression analysis.
(2) The result of analysis show there is a strong correlation between magnetic reluctance and structural parameters of gap section, gap length, pitch, teeth width and depth of slot.
The magnetic reluctance of air gap is calculated by using a, linear two-dimensional finite element method with scalar potentials. Harmonics of reluctance are obtained through FFT. Multiple correlation coefficients between harmonic and structural parameters are calculated on a linear multiple regression model. We test about regression coefficients at a significance level of 1% and clarify correlation between harmonic and gap length etc.

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In this paper, slot depth of armature core was examined in permanent magnet type linear synchronous motor (LSM) which adopted rail support construction from both sides of experiment and calculation. It was clear that the effect of the depth of the slot for the static thrust was small, if the permanent magnet of large magnet coercive force is installed, and the air gap is not especially big.

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In this paper, a relation between the limit value of thrust constant and size of a linear DC motor (LDM) that is moving coil type with unipolar is described. It is deduced the relation between the limit value of the thrust constant of the LDM and the dimension of the yokes. Its relation is defined as a relational equation. To maximize the rate of thrust to the volume of LDM, the magnetic flux density in the yoke is adjusted to the value of magnetic saturation. Then, the equation consists. It means that the thrust constant is in inverse proportion to the stroke and proportional to the sectional area of the center yoke. By measurement of the thrust of the LDM and result of the magnetic field analysis (finite element method), the validity of the equation is confirmed. The equation qualitatively agrees with the measurement result, and its maximum error is 26.0 percent. Then two type LDMs are designed to verify the accuracy of the relational equation. One LDM is thin (maximum thickness is 14mm) with long stroke (100mm) for pen recorder. Another LDM is for high response positioning system with strong thrust (20 N). The relational equation agrees well with measured thrust constants of these LDMs, its error is about 14 percent.

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　When compressive stress is applied to electrical steel sheets in their thickness direction, both permeability and magnetic losses change. The stress induced loss reduction was observed both ring and strip specimens, and they are mainly from hysteresis loss change due to the stress. Magnetizing process due to the stress is discussed by means of domain observations.

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Linear DC motors (LDMs) are widely used for servo-actuator, compressor and so on. High-efficiency LDMs are strongly desired for compressors. To realize the LDMs with high-efficiency characteristics, decreasing the copper losses, namely, thrust-to-input ratio, F/P, must be increased. This paper describes an optimization method for the F/P of a moving coil type LDM. The following results are obtained:
(1) Simplified expression for the F/P of the LDM is derived from the permeance analysis method. The effects that dimensions of the LDM influence the F/P of the LDM are investigated through the simplified expression for the F/P. As a result, the optimum dimension of the LDM for maximizing the F/P exists.
(2) When the static thrust is 100 N, the measured F/P of the initial LDM is 7.9 N/W, and the errors by using the simplified expression for the F/P and the finite element method (FEM) are 33% and 8%, respectively. Derived simplified expression for the F/P is useful because the F/P can be calculated easily.
(3) An improved LDM, which has 26% higher F/P than those of the initial LDM, is designed by using the permeance analysis method and the FEM.

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A cylindrical multi-degree-of-freedom stepping motor for linear and rotary motion is presented and the advantages of the motor are discussed. The stepping motor consists of stators for axial and angular movement and a mover. Considering the shape of the mover's teeth with respect to both axial and circumferential alignment, the magnetic reluctance of the air gap is analyzed to evaluate the maximum static thrust. Moreover, the effect of magnetic saturation is roughly estimated. Maximum static thrust for axial motion is determined to be 7.84 N and maximum static torque for angular motion is 4.9 × 10^-2 N·m. Compared with commercially available linear and rotary stepping motors, the merits and demerits of the multi-degree-of- freedom motor are discussed from the viewpoint of static force, mass and input. The new cylindrical motor not only achieves high performance, but realizes a simpler, smaller, lighter mechanism since gears or linkages are not needed.

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One of the main factors in the acoustic noise of power transformers is thought to be magnetostriction of the cores, because the magnetic flux deviates from the easy axes at the corners of the cores. Therefore, we measured the magnetostriction and observed the domain structure in single crystals of (100) Si-Fe sheets when the easy axes deviated from the exciting direction. Complicated behaviors involving shrinkage and expansion were observed in the measured magnetostriction. In the demagnetized state, 180° domain walls parallel to the [001] direction were observed. When a small field was applied, a [010] domain was generated at the edge of the sample. The [001] and the [010] domains are partitioned by a 90° domain wall, whose movement caused large shrinkage. In a larger field, rotation of the magnetization caused large expansion. Thus, it became clear that large vibrations with magnetostriction were generated at the corners of the core, even if the cube-textured Si-Fe was used as the core's material.

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In one of the glass sheet tempering process in which a glass sheet is submerged into molten metal with electromagnetic force by Linear Induction Motor (LIM), it is necessary to keep the glass sheet vertical in the center of molten metal tank. Because a glass sheet warps unless its both sides are uniformly cooled.
This paper describes an idea of buoyant force center on a glass sheet in molten metal which is introduced to discuss its stability against tilt. If the buoyant force center of a glass sheet is higher than its gravity center, it is stable against tilt. Numerical simulation of electromagnetic fluid flow is performed to evaluate the buoyant force center. Its stable conditions obtained are the followings:
(1) The shortest length of a glass sheet is 2τ/3 shorter than that of LIMs.
(2) The lowest limit of the gravity center of a glass sheet is τ/3 higher than the center of LIMs.
where τ is the pole pitch of LIMs.

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This paper describes the improvements in launching stability and launching velocity of the linear accelerator (LAC).
The authors have designed and produced a railgun using the LAC for weaving loom shuttles. The LAC is an electromagnetic launcher which enable a projectile to be launched at a speed of more than 50m/s. It basically consists of an uni-pole linear DC motor and operates the same principle as DC rotary motors, the most difficult problem in this system being the stabilization of the current collection on the projectile.
Then we have conducted the various launch experiments. As a result, we have achieved that the carbon projectile was launched at a speed of 73m/s using double-stage type LAC.

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