A piezo actuator comprises a piezo material having a first, top surface, a second, bottom surface, and a third, circumference surface. The piezo material has a polarity and the piezo material includes one or more mounting holes in the piezo material, the one or more mounting holes being positioned substantially central in at least the top surface or the bottom surface of the piezo material. The actuator also comprises at least one contact point for contacting a load to be actuated, the at least one contact point being positioned on the third, circumference, surface of the piezo material, and a set of electrodes being positioned on the top surface of the piezo material and at least one electrode being positioned at the bottom surface of the piezo material.

A vibration wave motor includes a rotational shaft body, an electrical-mechanical energy conversion element, a first elastic body that is fitted into the rotational shaft body and configured to vibrate by the electrical-mechanical energy conversion element, a positioning member configured to position the rotational shaft body in a rotation axis direction of the rotational shaft body, and a connection member configured to connect the first elastic body to the positioning member.

A piezo actuator comprises a piezo material having a first, top, surface, a second, bottom, surface, and a third, circumference, surface. The piezo material has a polarity and the piezo material Comprises one or more mounting holes in the piezo material, the one or more mounting holes being positioned substantially central in at least the top surface or the bottom surface of the piezo material. The actuator also comprises at least one contact point for contacting a load to be actuated, the at least one contact point being positioned on the third, circumference, surface of the piezo material, and a set of electrodes being positioned on the top surface of the piezo material and at least one electrode being positioned at the bottom surface of the piezo material.

A machining toolholder including a body, a horn and a piezoelectric actuator is disclosed. The body includes a center through hole extending in the axial direction therein. The center through hole includes a first hole section and a second hole section. The horn includes a first section and a second section which are disposed coaxially and connected with each other. Part of the first section is slidably inserted into the first hole section. The second section is connected to the body and engaged with a tool. Part of the surface of the second section contacts with a wall surface of the second hole section. The piezoelectric actuator fits around the horn and is controllable to drive the tool to vibrate. With this design, the machining toolholder could have good stiffness and connection stability, and could resist to the stress effectively.

A machining toolholder including a body, a horn and a piezoelectric actuator is disclosed. The body includes a center through hole extending in the axial direction therein. The center through hole includes a first hole section and a second hole section. The horn includes a first section and a second section which are disposed coaxially and connected with each other. Part of the first section is slidably inserted into the first hole section. The second section is connected to the body and engaged with a tool. Part of the surface of the second section contacts with a wall surface of the second hole section. The piezoelectric actuator fits around the horn and is controllable to drive the tool to vibrate. With this design, the machining toolholder could have good stiffness and connection stability, and could resist to the stress effectively.