Patents by Inventor Yasutomo Kawabata

Yasutomo Kawabata has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5791426
    Abstract: In a power output apparatus (20) of the present invention, a controller (80) controls a clutch motor (30) and an assist motor (40), thereby converting energy output from an engine (50) and expressed by the product of the revolving speed and the torque of a crankshaft (56) of the engine (50) to energy expressed by the product of the revolving speed and the torque of a drive shaft (22) and outputting the converted energy to the drive shaft (22). When the remaining charge of a battery (94) is less than a predetermined range, the battery (94) is charged with electric power, which is regenerated from part of the energy output from the engine (50) by either the clutch motor (30) and the assist motor (40). When the remaining charge of the battery (94) exceeds the predetermined range, on the other hand, part of electric power consumed by either the clutch motor (30) or the assist motor (40) is supplied by electric power released from the battery (94).
    Type: Grant
    Filed: September 30, 1996
    Date of Patent: August 11, 1998
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Eiji Yamada, Yasutomo Kawabata, Ryuji Toh
  • Patent number: 5789935
    Abstract: A method of evaluating a motor. Prior to testing the motor, the following factors are measured as essential properties of the motor, e.g. a correlation between a reference current and a motor current, reaction of the motor current, etc. in response to a variation of the reference current, a correlation between the reference current and a motor torque, temperature characteristics of the motor torque, a relationship between the torque, the number of rotations, efficiency of the motor, and so on. The measured essential properties include response delays of an evaluator and sensors, and influences of disturbances such as temperature. Data collected during testing are corrected on the basis of the measured essential properties using the reference currents as time criteria such that influences caused by response delays can be excluded. Thus, the performances of the motor can be precisely analyzed.
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: August 4, 1998
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Hiroshi Suga, Yasutomo Kawabata
  • Patent number: 5789877
    Abstract: A power transmitting apparatus (20) attached to a crankshaft (56) of an engine (50) includes a clutch motor (30), an assist motor (40), and a controller (80) for controlling the clutch motor (30) and the assist motor (40). When detecting an ignition switch in a starter position, the controller (80) makes a constant current flow through three-phase coils (44) of the assist motor (40) to fix a drive shaft (22) and makes a current flow through three-phase coils (36) of the clutch motor (30) to enable the clutch motor (30) to apply a starter torque TST to the crankshaft (56). This results in cranking the crankshaft (56). Concurrently with the cranking process, fuel injection into the engine (50) and spark ignition are controlled to start the engine (50).
    Type: Grant
    Filed: April 22, 1996
    Date of Patent: August 4, 1998
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Eiji Yamada, Takao Miyatani, Yasutomo Kawabata, Ryouji Mizutani, Akihiko Kanamori
  • Patent number: 5650706
    Abstract: A control device for a salient pole type permanent magnet motor. A magnetic flux of a magnet is detected by an arithmetic operation or actual measurement, and a demagnetization rate is calculated in accordance with the thus detected magnetic flux. A target of controlling the phase is calculated with reference to a demagnetization rate obtained by the calculation. The phase of a motor current is controlled depending on the target of control obtained by the calculation. Thus, a torque is prevented from lowering due to demagnetization of the magnet.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: July 22, 1997
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Eiji Yamada, Yasutomo Kawabata
  • Patent number: 5631512
    Abstract: Hard magnetic poles made of a permanent magnet and soft magnetic poles are alternately disposed on the periphery of a cylindrical rotor of a permanent magnet type synchronous motor. The arcuate length of the hard magnetic poles is equal to that of the intervals between the hard magnetic poles, thereby enabling an increase in the ratio of reluctance torque. Therefore, the number of permanent magnets used can be reduced, making production economical, and a back electromotive force can also be lowered. Further, one magnetic pole consists of six slots, and the arcuate length of hard and soft magnetic poles corresponds to a 3-slot pitch, thereby enabling a reduction in cogging torque.
    Type: Grant
    Filed: March 24, 1995
    Date of Patent: May 20, 1997
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yasutomo Kawabata, Tetsuya Miura
  • Patent number: 5623178
    Abstract: Molded coil pieces inserted into a slot are separately connected to molded coil pieces belonging to another slot of the same phase as the former coil pieces by a connecting member. The connecting member has conductive members laminated in a direction perpendicular to a rotating shaft of the rotor in the motor via insulating layers, and the molded coil pieces are separately connected to each other by these conductive members, whereby the protrusion of a coil end from each slot can be reduced, which permits the miniaturization and the weight reduction of the motor. Furthermore, the dimensional accuracy of the connecting members can be improved by a simple constitution and manufacturing process, whereby the characteristics of the electric motor can be remarkably improved.
    Type: Grant
    Filed: July 5, 1994
    Date of Patent: April 22, 1997
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yasutomo Kawabata, Eiji Yamada, Tetsuya Miura
  • Patent number: 5608300
    Abstract: The present invention provides a system for detecting a rotational orientation or electrical angle of a rotor without any specific sensor so as to efficiently control a synchronous motor even while the rotor is at a stop or rotates at a relatively low speed. An electrical angle of a rotor (50) is determined according to a previously stored relationship between inductances of different interphases and electrical angles. At a first step, an electrical angle .phi. is calculated either in a range of 0 through .pi. or in a range of .pi. through 2.pi. by approximation. At a second step, a range where the electrical angle .phi. belongs to is specified by taking advantage of asymmetrical property of a maximum current in response to a voltage applied to each interphase. An equivocal electrical angle .theta. is then determined in a range of 0 through 2.pi..
    Type: Grant
    Filed: October 24, 1994
    Date of Patent: March 4, 1997
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yasutomo Kawabata, Eiji Yamada, Tetsuya Miura, Yoshiaki Taga
  • Patent number: 5569995
    Abstract: A method and an apparatus for driving and controlling a synchronous motor using permanent magnets as its field system are herein disclosed. When a rotational speed of the synchronous motor using the permanent magnets as the field system is more than a base rotational speed, a current condition computing section computes a field weakening reference current in accordance with a battery voltage, a reference torque and a rotational speed. An inverter performs the field weakening control of the the synchronous motor using the permanent magnets as the field system in accordance with the field weakening reference current sent from the current condition computing section to prevent the deterioration of efficiency and the deficiency of output due to the excessive or insufficient field weakening current. The current condition computing section determines optimum reference current by the use of a converged battery voltage, when the battery voltage is converged to a constant value after initial control.
    Type: Grant
    Filed: August 10, 1994
    Date of Patent: October 29, 1996
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yasushi Kusaka, Eiji Yamada, Yasutomo Kawabata
  • Patent number: 5422526
    Abstract: A motor coil structure has a lamination of in-slot coils incorporated into slots in a stator core and inter-slot connecting wires individually connecting to the end faces of the in-slot coils. Each of the inter-slot connecting wires is in the form of a bar such that the in-slot coils received in two different slots spaced away from each other by slots equal in number to n-1 (where n is the number of phases). Since the space factor depends on the lamination of in-slot coils in the slot, any clearance in the slot can be eliminated to improve the space factor compared with a motor coil structure in which a coil is formed by binding and winding a plurality of wires.
    Type: Grant
    Filed: December 29, 1993
    Date of Patent: June 6, 1995
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yasutomo Kawabata, Kaoru Kubo, Tetsuya Miura
  • Patent number: 5157298
    Abstract: A brushless motor energized by an M-phase alternating current having a stator with M.multidot.m (m is an even number) teeth, a coil wound around each of the teeth, and a rotor with (M+1).multidot.m permanent magnets. Since the coil is wound around each tooth, cancellation of magnetic fluxes produced by adjacent coils is minimized, which results in a greater efficiency of the motor. Since one coil corresponds to less than one magnet, irregularity on the induced voltage of the coils barely occurs, which results in a smoother output torque of the motor.
    Type: Grant
    Filed: April 13, 1990
    Date of Patent: October 20, 1992
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Yasutomo Kawabata
  • Patent number: 5038090
    Abstract: A servo motor control apparatus effecting a feedback control of a servo motor according to an external operation command. The apparatus includes: an operational running state detecting unit for detecting a running state of the servo motor; a memory unit in which data representing inter-relation values are stored; a current value computing unit for computing an appropriate drive current value for the external operation comand; and a driving unit for driving the servo motor according to the computed appropriate drive current value.
    Type: Grant
    Filed: October 4, 1989
    Date of Patent: August 6, 1991
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yasutomo Kawabata, Ryoji Mizutani, Hirosumi Suzuki
  • Patent number: 4945231
    Abstract: In the compound rotary encoder of this invention, an absolute signal representing the upper m bits of a rotation angle signal, and an icreametal signal used for detecting the lower bits of the rotation angle signal are detected to obtain more detailed rotation angle information. Moreover, the rotation angle obtained by counting the increamental signal closely matches that obtained from the absolute signal, assuring the detection of the rotation angle with high resolution and precision. Since a rotating disk has only m bits of absolute code pattern, the rotary encoder can be small. This permits the absolute code pattern to have greater diametrical width so that a large output of the absolute signal can be stably obtained. On the other hand, the number of rotations can be obtained by counting and compensating a standard position signals. Since the rotary disk has the patterns both for detecting the standard position signal and for detecting the rotation angle, this too allows the rotary encoder to be small.
    Type: Grant
    Filed: June 1, 1989
    Date of Patent: July 31, 1990
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Hideshi Ohya, Takao Miyatani, Keiji Kawamura, Yasutomo Kawabata