Ultrasonic actuator and magnetic recording apparatus using the same

A magnetic recording apparatus, comprising:

• an ultrasonic actuator;
• the ultrasonic actuator including:
• a vibrating member having a substantially triangular shape with three vertices;
• the vibrating member includes:
• three piezoelectric deformation portions each of which includes each of the vertices and deforms when a voltage is applied thereto;
• a moving member which is provided so as to be pressure contacted to the three vertices of the vibrating member, the moving member being caused to move relative to the vibrating member by elliptical motions of the three vertices caused by deformations of the piezoelectric deformation portions;
• a recording medium which records information thereon;
• a magnetic head which reads and writes information from and in the recording medium;
• and
• an arm which is fixedly secured to the moving member of the ultrasonic actuator and supports the magnetic head movably relative to the recording medium.

An ultrasonic actuator, comprising:

• a vibrating member having a substantially triangular shape with three vertices;
• the vibrating member includes:
• three piezoelectric deformation portions each of which includes each of the vertices and deforms when a voltage is applied thereto;
• a moving member which is provided so as to be pressure contacted to the three vertices of the vibrating member and moves relative to the vibrating member,
• wherein one of the piezoelectric deformation portions is configured to be driven in an expansion and contraction vibration mode in which the one of the piezoelectric deformation portions deforms in an expansion and contraction manner so that the vertex of the one of the piezoelectric deformation portions reciprocally moves in a radial direction connecting the vertex thereof and a center of gravity of the vibrating member, and in a bending vibration mode in which the one of the piezoelectric deformation portions deforms in a bending manner so that the vertex thereof reciprocally moves in a circumferential direction approximately perpendicular to the radial direction, two resonance frequencies of the vibrating member in the expansion and contraction vibration mode and the bending vibration mode are identical, and the moving member is caused to move relative to the vibrating member by an elliptical motion of the vertex of the one of the piezoelectric deformation portions, which elliptical motion is caused by a vibration of the one of the piezoelectric deformation portions, which vibration is caused when the expansion and contraction vibration mode and the bending vibration mode are both simultaneously resonantly excited.

A magnetic recording apparatus, comprising:

• an ultrasonic actuator;
• the ultrasonic actuator including:
• a vibrating member having a substantially triangular shape with three vertices;
• the vibrating member includes:
• three piezoelectric deformation portions each of which includes each of the vertices and deforms when a voltage is applied thereto;
• a moving member which is provided so as to be pressure contacted to the three vertices of the vibrating member and moves relative to the vibrating member,
• wherein one of the piezoelectric deformation portions is configured to be driven in an expansion and contraction vibration mode in which the one of the piezoelectric deformation portions deforms in an expansion and contraction manner so that the vertex of the one of the piezoelectric deformation portions reciprocally moves in a radial direction connecting the vertex thereof and a center of gravity of the vibrating member, and in a bending vibration mode in which the one of the piezoelectric deformation portions deforms in a bending manner so that the vertex thereof reciprocally moves in a circumferential direction approximately perpendicular to the radial direction, two resonance frequencies of the vibrating member in the expansion and contraction vibration mode and the bending vibration mode are identical, and the moving member is caused to move relative to the vibrating member by an elliptical motion of the vertex of the one of the piezoelectric deformation portions, which elliptical motion is caused by a vibration of the one of the piezoelectric deformation portions, which vibration is caused when the expansion and contraction vibration mode and the bending vibration mode are both simultaneously resonantly excited,
• a recording medium which records information thereon;
• a magnetic head which reads and writes information from and in the recording medium;
• and
• an arm which is fixedly secured to the moving member of the ultrasonic actuator and supports the magnetic head movably relative to the recording medium.