Patent Application
20140188144
The present invention relates to an ultrasonic oscillation probe that transmits ultrasonic vibrations, a method for manufacturing the ultrasonic oscillation probe, and an ultrasonic treatment apparatus including the ultrasonic oscillation probe.
In recent years, ultrasonic treatment apparatus that perform a surgical operation on an affected part of a living body by using ultrasonic vibration have been widely used. For example, Japanese Patent No. 2532780 discloses an ultrasonic treatment apparatus that amplifies ultrasonic vibration generated from an ultrasonic oscillator with a horn of an ultrasonic oscillation probe, transmits the amplified ultrasonic vibration to a distal end of the ultrasonic oscillation probe, and performs treatment by the ultrasonic vibration. By using such a device, it is possible to press the distal end of the ultrasonic oscillation probe against the affected part of the living body to perform excision or the like of the affected part by the ultrasonic vibration.
The ultrasonic oscillation probe is a part that amplifies ultrasonic vibration generated in an ultrasonic vibrator with the horn of the ultrasonic oscillation probe, and transmits the ultrasonic vibration to the distal end (affected part of the living body) of the ultrasonic oscillation probe. Regarding the performance required of the ultrasonic oscillation probe, durability against the ultrasonic vibration, the characteristic of stably and efficiently transmitting the vibration, excellent compatibility with the living body, and the like are required. As materials that satisfy these required characteristics, pure titanium and titanium-based alloys are used. Since the pure titanium and titanium-based alloys have higher strength, the durability and the compatibility with the living body are also excellent.
As a result of close study in order to solve the above problems, the present inventors have found that heat generated by ultrasonic vibration can be suppressed by coarsening crystal grain size in a metal structure, and have completed the present invention.
According to a first aspect of the present invention, in an ultrasonic oscillation probe for transmitting ultrasonic vibration, the ultrasonic oscillation probe includes a first region and a second region. A first crystal grain size of the first region is smaller than a second crystal grain size of the second region, and the first region and the second region are respectively formed in at least one place.
According to a second aspect of the present invention, the ultrasonic oscillation probe of the first aspect may include a proximal end connected to an ultrasonic oscillator that generates the ultrasonic vibration; and a distal end that exerts the ultrasonic vibration transmitted from the proximal end to the outside, and one or more sets of the first region and the second region may be alternately arranged along a direction toward the distal end from the proximal end.
According to a third aspect and a fourth aspect of the present invention, the ultrasonic oscillation probe of the first aspect or the second aspect may include a horn that amplifies the ultrasonic vibration; and a probe that transmits the amplified ultrasonic vibration, and the crystal grain size of the horn and the crystal grain size of the probe may be different from each other.
According to a fifth aspect of the present invention, in the ultrasonic oscillation probe of the third aspect, the crystal grain size of the horn may be larger than the crystal grain size of the probe.
According to a sixth aspect of the present invention, the ultrasonic oscillation probe of any one to the first aspect to the fifth aspect may contain pure titanium.
According to a seventh aspect of the present invention, the ultrasonic oscillation probe of any one to the first aspect to the fifth aspect may contain a titanium alloy.
According to an eighth aspect of the present invention, in the ultrasonic oscillation probe of any one to the third aspect to the fifth aspect, the horn may contain an aluminum alloy, and the probe may contain a titanium alloy.
According to a ninth aspect of the present invention, in the ultrasonic oscillation probe of any one to the first aspect to the fifth aspect, the second region may be formed by being heated to a grain coarsening temperature or higher of a material that forms the ultrasonic oscillation probe.
According to a tenth aspect of the present invention, in the ultrasonic oscillation probe of any one to the first aspect to the fifth aspect, the second region may be formed by being heated to and forged at a grain coarsening temperature or higher of a material that forms the ultrasonic oscillation probe.
According to an eleventh aspect of the present invention, in a method for manufacturing an ultrasonic oscillation probe for transmitting ultrasonic vibration, the method includes the steps of: respectively forming a first region and a second region in at least one place so that a first crystal grain size of the first region is smaller than a second crystal grain size of the second region, and heating a portion of the ultrasonic oscillation probe to a grain coarsening temperature or higher of a material that forms the ultrasonic oscillation probe, to form the second region.
Even in the method for manufacturing the ultrasonic oscillation probes of the second aspect to the fifth aspect, in heating, the second region may be formed by heating a portion of the ultrasonic oscillation probe to a grain coarsening temperature or higher of a material that forms the ultrasonic oscillation probe.
According to a twelfth aspect of the present invention, in the method for manufacturing an ultrasonic oscillation probe of the eleventh aspect, the second region may be formed by heating and forging a portion of the ultrasonic oscillation probe.
An ultrasonic treatment apparatus according to a thirteenth aspect includes an ultrasonic oscillator that generates the ultrasonic vibration; and the ultrasonic oscillation probe according to any one of the first aspect to the fourth aspect that is connected to the ultrasonic oscillator.
An embodiment of the present invention will be described below with reference to the drawings.
The present embodiment relates to an ultrasonic oscillation probe that amplifies ultrasonic vibration to transmit the vibrations to a probe distal end, a method for manufacturing the ultrasonic oscillation probe, and an ultrasonic treatment apparatus including the ultrasonic oscillation probe.
An ultrasonic treatment apparatus 1 of the present embodiment, as shown in
The main body section 10 has a controller that controls the operation of the ultrasonic oscillator 20 that generates ultrasonic waves. The ultrasonic oscillation probe 30 has a proximal end connected to the ultrasonic oscillator 20, and a distal end that exerts ultrasonic vibration transmitted from the proximal end operate. In addition, in the present embodiment, the ultrasonic vibration generated from the ultrasonic oscillator 20, as indicated by the arrow of
The distal end of the covering portion 50, as shown in
The ultrasonic oscillation probe 30, as shown in
The horn 31 has the second end (the right side in
The horn 31 described above is formed in a shape that gradually decreases in diameter toward the first end 31a (that is, toward a direction in which the ultrasonic vibration is transmitted) from the second end 31b. By virtue of this configuration, the ultrasonic vibration is amplified while being transmitted through the horn 31.
In the present embodiment, the horn 31 is made of higher-strength metallic materials, such as titanium alloys including a 64 titanium alloy, pure titanium, and duralumin. When titanium alloys and pure titanium are used for the horn 31, particularly, strength is high and the durability is excellent. Additionally, when aluminum alloys represented by duralumin are used for the horn 31, costs can be reduced.
A second end 32b of the probe 32 is coupled to the first end 31a of the horn 31, and has a shape that extends toward the distal end 30b side. In the present embodiment, the external diameter of the probe 32 is constant from the first end 32a to the second end 32b. The probe 32, specifically, performs treatment, inspection, or the like as the ultrasonic vibration amplified by the horn 31 is transmitted to the distal end of the probe 32 and the distal end of the probe 32 is pressed against an object. In the present embodiment, the probe 32 is made of metallic materials having higher strength and excellent biocompatibility, such as titanium alloys, such as a 64 titanium alloy, pure titanium, or the like.
Also, in the ultrasonic oscillation probe 30 of the present embodiment, a region (a first region) where the crystal grain size is relatively small and a region (a second region) where the crystal grain size is relatively large are arranged along a direction (the longitudinal direction of the ultrasonic oscillation probe 30) that goes from the proximal end 30a of the ultrasonic oscillation probe 30 to the distal end 30b thereof. In the present embodiment, the crystal grain size (first crystal grain size) of the above-described horn 31 is large compared to the crystal grain size (second crystal grain size) of the probe 32. That is, the horn 31 is formed with a region where crystal grains are coarsened and the crystal grain size is relatively large, compared to the probe 32.
Specifically, in the present embodiment, in the case of the 64 titanium alloy, the crystal grain size of the horn 31 is set to be equal to or larger than 3 μm and equal to or smaller than 500 μm. More preferably, the crystal grain size of the horn is equal to or larger than 3 μm and equal to or smaller than 300 μm. As specific examples, optical microscope photographs of a metal structure of one end of the horn are shown in FIGS. 3A and 3B.
Additionally, the crystal grain size of the probe 32 is set to be equal to or smaller than 2 μm. More preferably, the crystal grain size of the probe is equal to or smaller than 1 μm. As specific examples, optical microscope photographs of the metal structure of the probe 32 are shown in
Next, a method for manufacturing the ultrasonic oscillation probe 30 of the present embodiment will be described.
The ultrasonic oscillation probe 30 of the present embodiment is manufactured by an electric upsetting, which is a kind of forging. The electric upsetting, as shown in
In the present embodiment, a portion of the rod material is heated to a grain coarsening temperature (transformation temperature of a metallic material) or higher, at which crystal grains of the metallic material that constitutes the ultrasonic oscillation probe 30 are coarsened, and the upset processing is performed to make the horn 31 having a desired crystal grain size. Specifically, the temperature at which the crystal grains are coarsened is equal to or higher than 990° C. in the case of 64 titanium, is equal to or higher than 885° C. in the case of pure titanium, and is equal to or higher than 480° C. in the case of 7075-T6 of duralumin. Then, the rod material is cut with a predetermined length to obtain the ultrasonic oscillation probe 30 having the horn 31 and the probe 32. In this way, the crystal grains of the horn 31 are made coarser than the crystal grains of the probe 32, and form the region where the crystal grain size is relatively large.
When oxidization or the like has occurred on the surface of the ultrasonic oscillation probe 30 during the processing, an oxide layers may be removed by pickling, cutting, or the like. Additionally, in order to suppress the oxidization of the surface layer, heat treatment may be performed in a vacuum atmosphere or an argon gas atmosphere.
The ultrasonic oscillation probe 30 having such a configuration is used in the ultrasonic treatment apparatus 1 shown in
Next, a method for using the ultrasonic treatment apparatus 1 will be described. First, the main body section 10 is operated to generate ultrasonic vibration from the ultrasonic oscillator 20 and transmit vibrations to the ultrasonic oscillation probe 30. Then, the ultrasonic vibration is amplified by the horn 31 and further transmitted to the distal end (one end) of the probe 32. An operator of the ultrasonic treatment apparatus 1 grips, for example, a patient's affected part to be excised, between the distal end of the ultrasonic oscillation probe 30 and the jaw portion 51 while gripping the handle 40 with a hand. Thereafter, the affected part can be excised by generating ultrasonic vibrations. Next, the ultrasonic vibration can be stopped and the handle 40 can be operated to grip the excised piece by the distal end 30b of the ultrasonic oscillation probe 30 and the jaw portion 51 and remove the excised piece from the body.
According to the ultrasonic oscillation probe 30 of the present embodiment having the configuration described above, the crystal grain size of the horn 31 is larger than the crystal grain size of the probe 32. Thus, heat generation of the horn 31 occurring during the magnification of the ultrasonic vibration can be suppressed, degradation of the ultrasonic oscillation probe 30 can be suppressed, and the durability can be improved. Additionally, since the crystal grain size of the distal end of the probe 32 is smaller than that of the horn 31, the 0.2% proof stress becomes high. Accordingly, when the ultrasonic oscillation probe 30 is used for the ultrasonic treatment apparatus 1 in practice, plastic deformation does not occur easily and the durability is excellent.
That is, the horn 31 where ultrasonic vibration is amplified is a site where the most heat is generated (vibrational energy is easily converted into heat energy) in the ultrasonic oscillation probe 30 because the vibrational energy is amplified (densified). Due to this heat generation, the horn 31 and the probe 32 have a high temperature and deteriorate easily. It is believed that this heat generation occurs due to the friction of a crystal interface caused by vibrations, and it is preferable that crystal interface per unit cross-sectional area in a plane in a direction parallel to the diameter of the horn 31 be smaller so that the heat generation of the horn 31 is suppressed. Therefore, in the present embodiment, the crystal grain size of the horn 31 is set to be equal to or larger than 3 μm and equal to or smaller than 500 μm, and more preferably, equal to or larger than 3 μm and equal to or smaller than 300 μm.
Since the crystal grain size of the horn 31 is set to be equal to or larger than 3 μm and equal to or smaller than 500 μm, the heat generation occurring during the magnification of the ultrasonic vibration can be sufficiently suppressed, and the durability can be further improved. Additionally, when the crystal grain size of the horn 31 is larger than 500 μm, the heat generation during the ultrasonic vibration is further suppressed. However, in this case, degradation of mechanical strength (0.2% proof stress or the like) is large. For example, when being used for the ultrasonic treatment apparatus, the durability degradation caused by the strength degradation occurs such that breaking occurs during use. Therefore, the upper limit of the crystal grain size is set to the above range.
Meanwhile, since the distal end (first end) 32a of the probe 32 is brought into contact with an object, the distal end 32a of the probe 32 is stressed. In order to transmit the ultrasonic vibration transmitted to the distal end to a target member (a patient's affected part or the like), it is required that the transmission of the ultrasonic transmission is not cut off when the distal end is plastically deformed even if the distal end is stressed, and the strength (0.2% proof stress) that withstands such stress is required. In order to enhance this strength, it is preferable that the metal structure be made fine. Therefore, in the present embodiment, the crystal grain size of the probe 32 is equal to or smaller than 2 μM, and more preferably, equal to or smaller than 1 μm.
In this way, since the crystal grain size of the distal end 32a of the probe 32 is set to be equal to or smaller than 2 μm, the 0.2% proof stress is high, the plastic deformation does not occur at the distal end, and the durability of the ultrasonic oscillation probe 30 can be improved.
According to the method for manufacturing the ultrasonic oscillation probe 30 of the present embodiment, the horn 31 is formed by performing heating only on the processing site. Accordingly, the crystal grain size of the horn 31 is large, and it is possible to obtain the ultrasonic oscillation probe 30 in which the crystal grain size of the probe 32 is small.
According to the ultrasonic treatment apparatus 1 of the present embodiment, since the ultrasonic oscillation probe 30 having a configuration in which the crystal grain size of the horn 31 is large and the crystal grain size of the distal end of the probe 32 is small is included, heat generation occurring in the horn 31 due to the ultrasonic vibration can be suppressed. Additionally, since the crystal grain size of the distal end 32a of the probe 32 is small, the strength is high, and the plastic deformation does not easily occur even if the distal end 32a of the probe 32 is stressed. By virtue of these, the degradation of the ultrasonic oscillation probe 30 can be suppressed and the reliability of the ultrasonic treatment apparatus 1 that performs a surgical operation or the like can be improved.
Although the ultrasonic oscillation probe, the method for manufacturing the ultrasonic oscillation probe, and the ultrasonic treatment apparatus, which is one embodiment of the present invention, have been described above, the present invention is not limited to this, and can be appropriately changed without departing from the technical idea of the present invention.
Although a case where the crystal grain size of the horn is large and the crystal grain size of the distal end of the probe is small has been described in the above embodiment, an ultrasonic oscillation probe having a configuration in which at least one region where the crystal grain size is small and at least one region where the crystal grain size is relatively large are respectively formed may be adopted.
Additionally, as shown in
Due to the reasons described above, the configuration shown in
Additionally, although a case where the probe is formed by the upset processing has been described in the above embodiment, the horn and the probe may be made by performing cutting work on a metallic material heated to a temperature or higher at which crystal grains are coarsened.
Additionally, the horn and the probe may be made by performing cutting work on a metallic material, and then, heat treatment may be performed on a predetermined site at a temperature or higher at which crystal grains are coarsened.
Additionally, the ultrasonic oscillation probe may be made by performing cutting work after a metallic material in which crystal grains are coarsened by being heated to a temperature or higher at which the crystal grains are coarsened, and a metallic material with fine structure are joined.
Additionally, although the method of performing heat treatment on a metallic material at a temperature or higher at which crystal grains are coarsened, and of manufacturing the ultrasonic oscillation probe by the electric upset method has been described, other hot forging methods may be used.
Additionally, although a case where the heat treatment method when the ultrasonic oscillation probe is manufactured is electric heating has been described in the above embodiment, an electric furnace, a burner, high-frequency induction heating, or the like may be used.
Additionally, in the above embodiment, a configuration may be adopted in which quenching is performed by quenching means, such as water cooling after heat treatment is performed and crystal grains are coarsened.
Although examples of the present invention will be described below in detail, the present invention is not limited to these and can be appropriately changed without departing from the technical idea.
A horn and a probe were made by using a rod material made of a commercially available 64 titanium alloy, performing the electric upsetting on one end of the rod material, and facing the surface of the rod material with cutting work to remove an oxide layers. The electric upsetting was performed under a condition in which the maximum heat treatment temperature was 1105° C. (measured by a radiation thermometer). Next, an ultrasonic oscillation probe was obtained by performing vacuum heating at a highest attained temperature of 650° C. in order to remove the processing stress of the surface during the facing.
A horn and a probe were made by using a rod material made of a commercially available 64 titanium alloy, performing the electric upsetting on one end of the rod material, and facing the surface of the rod material with cutting work to remove an oxide layers. The electric upsetting was performed under a condition in which the highest heat treatment temperature was 1046° C. (measured by the radiation thermometer).
Next, an ultrasonic oscillation probe was obtained by performing vacuum heating at a highest arrival temperature of 650° C. in order to remove the processing stress of the surface during the facing.
A horn and a probe were made by performing cutting work on a rod material made of a commercially available 64 titanium alloy. Thereafter, an ultrasonic oscillation probe was obtained by performing vacuum heating at a highest arrival temperature of 650° C.
Next, a method for evaluating the performance of the examples of the present invention will be described.
(A) Vibration Characteristics
Second ends of the horns of the ultrasonic oscillation probes obtained on respective manufacturing conditions were connected to the ultrasonic oscillator, and the temperatures of the ultrasonic oscillation probes were measured. Continuous vibration for 5 minutes was performed with an ultrasonic wave of 60 kHz as the condition of the ultrasonic vibration, and highest heat generation temperatures in that case were performed. The temperatures were measured by the radiation thermometer.
(B) Crystal Grain Sizes
The crystal grain sizes were measured by performing observation of the metal structure of cross-sections parallel to the diameter of the horns with an optical microscope, and conforming to JIS G 0551 using observation photographs of the optical microscope.
(C) 0.2% Proof Stress
Tensile test pieces from sites where the crystal grain size is the same as the horns were made. The test method was performed according to JIS Z2201 and Z2241.
The results of evaluation of Example 1, Example 2, and Comparative Example 1 are shown in Table 1.
Since the crystal grain sizes of the horns were large in Example 1 and Example 2, the heat generation during the ultrasonic vibration was small, the 0.2% proof stress was high, and the performance was excellent. In contrast, since the crystal grain size was small in Comparative Example 1, the heat generation during the ultrasonic vibration was large, and the performance of the ultrasonic oscillation probe was inferior to Example 1 and Example 2.
A horn and a probe were made by using a rod material made of a commercially available JIS4 type pure titanium, performing the electric upsetting on one end of the rod material, and facing the surface of the rod material with cutting work to remove an oxide layers. The electric upsetting was performed under a condition in which the highest heat treatment temperature was 1468° C. (measured by the radiation thermometer). Next, an ultrasonic oscillation probe was obtained by performing vacuum heating at a highest arrival temperature of 650° C. in order to remove the processing stress of the surface during the facing.
A horn and a probe were made by performing cutting work on a commercially available JIS4 type rod material. Thereafter, an ultrasonic oscillation probe was obtained by performing vacuum heating at a highest arrival temperature of 650° C.
The results obtained by performing the above evaluation test on Example 3 and Comparative Example 2 are shown in Table 2.
Since the crystal grain size is large in Example 3, the highest arrival temperature during the ultrasonic vibration was low, the 0.2% proof stress was high, and the performance was excellent. In contrast, since the crystal grain size was small in Comparative Example 2, the highest arrival temperature during the ultrasonic vibration was high, and the performance was inferior to Example 3.
A horn shape was processed by using a commercially available duralumin (7075-T6) rod material, performing the electric upsetting on one end of the rod material, and facing the surface of the rod material with cutting work to remove an oxide layers. The electric upsetting was performed under a condition that the highest heat treatment temperature was 615° C. (measured by the radiation thermometer). Next, a horn was obtained by performing vacuum heating at a highest arrival temperature of 420° C. in order to remove the processing stress of the surface during the facing.
Next, a probe shape was processed by performing cutting work on a rod material made of a commercially available 64 titanium alloy. Vacuum heat treatment was performed at a highest arrival temperature of 650° C. in order to remove the processing stress of the surface during the cutting work.
Then, an ultrasonic oscillation probe was obtained by performing coupling between one end of the made horn and a proximal end of the probe by screw clamping.
A horn shape was processed by performing cutting work on a commercially duralumin rod material. Thereafter, a horn was obtained by performing vacuum heating at a highest arrival temperature of 420° C. in order to remove the processing stress of the surface during the cutting. Next, a probe shape was processed by performing cutting work on a commercially available 64 titanium alloy, and vacuum heat treatment was performed at a highest arrival temperature of 650° C. in order to remove the processing stress of the surface.
The results obtained by performing the above evaluation test on Example 4 and Comparative Example 3 are shown in Table 3. In addition, test pieces were made from the horns and the tensile test was performed.
Since the crystal grain size is large in Example 4, the highest arrival temperature during the ultrasonic vibration was low, the 0.2% proof stress was high, and the performance was excellent. Additionally, the cost of the ultrasonic oscillation probe having such a configuration can be reduced. In contrast, since the crystal grain size of the horn was small in Comparative Example 3, the highest arrival temperature during the ultrasonic vibration was high, and the performance was inferior to Example 4.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-251530 | Nov 2011 | JP | national |
This application is a continuation application based on PCT/JP2012/079809, filed on Nov. 16, 2012, claiming priority based on Japanese Patent Application No. 2011-251530, filed in Japan on Nov. 17, 2011. The contents of both the Japanese Patent Application and the PCT Application are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2012/079809 | Nov 2012 | US |
| Child | 14200519 | US |
