JP7411492B2 - Gear grinding equipment and gear grinding tools - Google Patents

Description

The present invention relates to a gear grinding device and a gear grinding tool that perform generation processing on gears, and particularly to a gear grinding device and a gear grinding tool that can process tooth surfaces with high precision using ultrasonic vibration.

Conventionally, gear grinding devices equipped with ultrasonic generators are known. In this type of gear grinding device, ultrasonic vibrations generated from an ultrasonic generator are transmitted to a gear grinding tool, and the tooth surface of the gear is ground with the gear grinding tool that vibrates ultrasonically.

For example, Patent Document 1 discloses a cradle-type bevel gear generating device that includes an ultrasonic generator that applies ultrasonic vibration to a cutting tool shaft. The cradle-type bevel gear generating device disclosed in the same document tilts the work shaft with respect to the cradle shaft and applies ultrasonic vibration to the rotating cutting tool while swinging the trapezoidal conical workpiece fixed to the work shaft. The cutting tool is then used to create a tooth profile on the outer circumferential surface of the workpiece.

For example, Patent Document 2 discloses that while a tool gear shaped to mesh with a workpiece is engaged with a gear after gear cutting in a cutting process, ultrasonic vibration is applied to the tool gear to grind the tooth surface. A gear grinding device is disclosed.

Japanese Patent Application Publication No. 2011-31317 Japanese Patent Application Publication No. 2002-144150

In recent years, the use of gears has been increasing in various robots, electronic devices, and other precision machines that perform precise movements, and gears are used in various sizes of high-precision gears that are quiet, have little vibration, and can transmit power with high efficiency. gears are required. Therefore, in manufacturing gears, there is a need for advanced processing technology that can efficiently finish tooth surfaces with high precision.

However, with the conventional gear grinding device described above, it is easy to further reduce the grinding streaks formed on the tooth surface by grinding, to further improve the precision of the tooth surface, and to process high-precision gears with high efficiency. The problem was that it wasn't.

Specifically, it is necessary to bring the ultrasonic vibration into a state suitable for grinding at the cutting edge of a grinding tool that comes into contact with a tooth surface to process the tooth surface. Even if ultrasonic vibration is applied to the grinding tool from an ultrasonic generator, if the cutting edge of the grinding tool that grinds the tooth surface does not vibrate with ultrasonic waves suitable for grinding, it will not be possible to finish the tooth surface with high precision. Can not.

For example, the conventional technology disclosed in Patent Document 2 hones a gear-cut workpiece using a tool gear that meshes with the workpiece, and grinds the gear using ultrasonic vibrations with high efficiency. It's not possible.

In addition, gear grinding equipment has become more sophisticated and the machining process has become more complex in order to meet the demands for even higher accuracy in tooth surface machining, resulting in lower gear productivity and the difficulty of reducing production costs. There is also.

The present invention has been made in view of the above circumstances, and its purpose is to provide a gear grinding device and a gear grinding tool with excellent productivity that can efficiently create high-precision gears. There is a particular thing.

The gear grinding device of the present invention includes a work shaft that rotatably supports a work, a grinding tool whose cutting edge moves in the tooth trace direction while rotating to grind a tooth surface on the work, and an output from an ultrasonic oscillator. an ultrasonic vibrator that generates ultrasonic vibrations in the rotational axis direction of the grinding tool; and a booster that connects the ultrasonic vibrator and the grinding tool to amplify the ultrasonic vibrations; The cutting edge vibrates ultrasonically in the tooth profile direction with respect to the tooth surface , and the base metal of the grinding tool is formed with a small diameter portion having a smaller diameter than both ends at the center in the direction of the rotation axis. Features.
The gear grinding device of the present invention also includes a work shaft that rotatably supports a work, a grinding tool whose cutting edge moves in the tooth trace direction while rotating to grind a tooth surface on the work, and an ultrasonic oscillator. an ultrasonic vibrator that generates ultrasonic vibrations in the rotational axis direction of the grinding tool by an output of the grinding tool; and a booster that connects the ultrasonic vibrator and the grinding tool to amplify the ultrasonic vibrations. , the cutting edge ultrasonically vibrates in the tooth profile direction with respect to the tooth surface, and the base metal of the grinding tool is formed with a large diameter part having a larger diameter than both ends at the center in the direction of the rotation axis. The base metal has one end surface in the direction of the rotation axis fixed to the booster, the other end surface fixed to a second booster that amplifies the ultrasonic vibration, and the rotation center of the base metal is characterized in that a cavity is formed during gear grinding, the cutting edge is formed in a thread shape on the outer periphery of the large diameter portion, and the workpiece is created as a parallel shaft gear. do.

Further, the gear grinding tool of the present invention is a gear grinding tool used in a gear grinding device having an ultrasonic vibrator, and is a rotating table having one end face fixed to a booster connected to the ultrasonic vibrator. and a cutting edge that is provided on the base metal and moves the processed surface of the workpiece in the tooth trace direction to grind the tooth surface on the workpiece, and the cutting edge is oscillated by the ultrasonic vibrator. The ultrasonic vibration amplified by the booster causes ultrasonic vibration in the tooth profile direction with respect to the tooth surface, and the base metal is formed with a small diameter part smaller in diameter than both ends at the center in the direction of the rotation axis. It is characterized by the presence of
Further, the gear grinding tool of the present invention is a gear grinding tool used in a gear grinding device having an ultrasonic vibrator, and is a rotating table having one end face fixed to a booster connected to the ultrasonic vibrator. and a cutting edge that is provided on the base metal and moves the processed surface of the workpiece in the tooth trace direction to grind the tooth surface on the workpiece, and the cutting edge is oscillated by the ultrasonic vibrator. The ultrasonic vibration amplified by the booster causes ultrasonic vibration in the tooth profile direction with respect to the tooth surface, and the base metal is formed with a large diameter portion having a larger diameter than both ends at the center in the direction of the rotation axis. The base metal has one end face in the direction of the rotation axis fixed to the booster, the other end face fixed to a second booster that amplifies the ultrasonic vibration, and a rotation center portion of the base metal. is characterized in that a cavity is formed during gear grinding, the cutting edge is formed in a screw shape on the outer periphery of the large diameter portion, and the workpiece is created as a parallel axis gear. .

According to the gear grinding device of the present invention, a work shaft rotatably supports a work, a grinding tool whose cutting edge moves in the tooth trace direction while rotating to grind a tooth surface on the work, and an ultrasonic oscillator. It has an ultrasonic vibrator that generates ultrasonic vibrations in the direction of the rotation axis of the grinding tool in response to a signal, and a booster that connects the ultrasonic vibrator and the grinding tool to amplify the ultrasonic vibrations. Ultrasonic vibrations occur in the tooth profile direction with respect to the surface.

Such a configuration enables highly accurate tooth surface grinding with fewer grinding streaks. Additionally, oil pockets can be formed on the tooth surface by grinding with suitable ultrasonic vibration. Therefore, a gear with excellent tooth surface properties, such as a low coefficient of friction on the tooth surface, low noise and vibration, high strength, and high conformability and lubricity, can be obtained.

Further, since the cutting edge moves in the tooth trace direction and ultrasonically vibrates with suitable strength in the tooth profile direction, highly efficient gear grinding can be performed at a low circumferential speed. In addition, high-precision gear machining is possible even when using a small-diameter grinding tool. Thereby, productivity of the gear grinding device and gears can be improved, and production costs can be reduced.

According to the gear grinding device of the present invention, the base metal of the grinding tool has a small diameter portion having a smaller diameter than both ends or a large diameter portion having a larger diameter than both ends at the center in the direction of the rotation axis. may be formed. With such a configuration, suitable ultrasonic vibrations can be transmitted to the cutting edge that grinds the tooth surface, and highly accurate and highly efficient gear grinding becomes possible.

Further, according to the gear grinding device of the present invention, the base metal of the grinding tool has a small diameter portion formed in the center in the direction of the rotation axis, and the diameter of the base metal is smaller than that of both ends. One end surface in the direction of the rotating shaft may be fixed to the booster, and the cutting edge may be formed on the other end surface, and the workpiece may be created as a bevel gear. Thereby, a highly accurate bevel gear with excellent tooth surface properties can be processed with high efficiency.

Further, according to the gear grinding device of the present invention, the small diameter portion may be formed in a hyperboloid shape. With such a base metal shape, ultrasonic vibrations can be efficiently transmitted to the cutting edge in a suitable state, grinding can be performed with high accuracy and efficiency, and a gear with excellent tooth surface properties can be obtained.

Further, according to the gear grinding device of the present invention, the base metal of the grinding tool has a large diameter portion formed in the center in the direction of the rotation axis, and the base metal has a larger diameter than both ends. One end surface in the direction of the rotational axis is fixed to the booster, the other end surface is fixed to a second booster that amplifies the ultrasonic vibration, and the cutting edge has a screw-like shape on the outer periphery of the large diameter portion. The workpiece is formed into a parallel shaft gear. Thereby, it is possible to create a parallel shaft gear with high precision, low noise, and low vibration.

Further, according to the gear grinding device of the present invention, a cavity may be formed in the base metal at the center of rotation. Thereby, the ultrasonic vibration of the cutting edge can be brought into a state suitable for grinding, thereby improving machining accuracy and machining efficiency.

Further, according to the gear grinding tool of the present invention, there is provided a base metal that rotates with one end face fixed to a booster connected to an ultrasonic vibrator, and a base metal that is provided on the base metal and rotates the machined surface of the workpiece in the tooth trace direction. It has a cutting edge that moves to grind the tooth surface on the workpiece, and the cutting edge vibrates ultrasonically in the direction of the tooth profile of the tooth surface by ultrasonic vibration amplified by the booster, and the base metal has a A small diameter portion having a smaller diameter or a large diameter portion having a larger diameter than both ends is formed in the center. Thereby, the ultrasonic vibration from the booster can be transmitted to the cutting edge in a state suitable for grinding, and the cutting edge can be caused to vibrate ultrasonically. Therefore, highly accurate gears can be efficiently created.

1 is a diagram showing a schematic configuration of the vicinity of a grinding tool of a gear grinding device according to an embodiment of the present invention. 1 is a diagram showing a grinding tool of a gear grinding device according to an embodiment of the present invention. FIG. 3 is a diagram showing a direction in which a tooth surface is ground by a cutting edge of a grinding tool of a gear grinding device according to an embodiment of the present invention. It is a figure which shows the schematic structure of the grinding tool vicinity of the gear grinding apparatus based on other embodiment of this invention. It is a figure of the grinding tool of the gear grinding device concerning other embodiments of the present invention.

Hereinafter, a gear grinding device according to an embodiment of the present invention will be described in detail based on the drawings.
FIG. 1 is a diagram showing a schematic configuration of the vicinity of a grinding tool 10 of a gear grinding device 1 according to an embodiment of the present invention.

The gear grinding device 1 is, for example, a cradle-type or electrically controlled manufacturing device that grinds bent bevel gears, hypoid gears, and the like. As shown in FIG. 1, the gear grinding device 1 includes a work shaft 6 that rotatably supports a work W, a grinding tool 10 as a gear grinding tool that grinds the work W, an ultrasonic oscillator 2, and an ultrasonic vibration. It has a child 3 and a booster 4.

The work shaft 6 supports a work W to be machined, which is created as a gear. The work shaft 6 is connected to a drive motor (not shown), rotatably supports the work W, and is configured to be tiltable and position changeable with respect to the rotation shaft of the grinding tool 10. Also good.

The grinding tool 10 is supported by a column (not shown) having a feed mechanism (not shown) and a drive motor, and generates a gear on the work W while rotating. Specifically, the grinding tool 10 has a base metal 12 having a substantially cylindrical shape that rotates around its central axis, and the base metal 12 has a tooth trace direction X of the workpiece W (see FIG. 3). A cutting edge 11 is formed that contacts the workpiece W while moving to grind the tooth surface W1 (see FIG. 3).

The ultrasonic oscillator 2 is a device that supplies signals and power for causing the ultrasonic vibrator 3 to oscillate ultrasonic vibrations. The ultrasonic oscillator 2 is connected to a control device (not shown) of the gear grinding device 1, and sends an ultrasonic vibration signal necessary for grinding the workpiece W to the ultrasonic vibrator 3 based on a signal from the control device. .

The ultrasonic vibrator 3 is a device that generates ultrasonic vibrations necessary for grinding the workpiece W based on the signal from the ultrasonic oscillator 2. Specifically, the ultrasonic vibrator 3 converts the electric power from the ultrasonic oscillator 2 into ultrasonic vibration in the direction of the rotation axis of the grinding tool 10 and transmits it to the booster 4 .

The booster 4 is a device that amplifies ultrasonic vibrations. The booster 4 connects the ultrasonic vibrator 3 and the grinding tool 10. That is, the booster 4 has one end 4a connected to the ultrasonic vibrator 3, and the other end 4b connected to the grinding tool 10. Ultrasonic vibrations emitted from the ultrasonic vibrator 3 are amplified by the booster 4 and transmitted to the grinding tool 10.

FIG. 2 is a diagram showing the grinding tool 10 of the gear grinding device 1. As shown in FIG.
Referring to FIGS. 1 and 2, the base metal 12 has one end 15 fixed to the booster 4 connected to the ultrasonic transducer 3, and the other end 16 fixed to the booster 4 connected to the ultrasonic transducer 3. A cutting edge 11 is formed to move the workpiece surface of the workpiece W in the tooth trace direction X to grind the workpiece W.

The cutting edge 11 is a grinding wheel having a substantially annular shape protruding from the end surface of the end portion 16 of the base metal 12, and is, for example, an electrodeposited grinding wheel having abrasive grains such as cBN, diamond, WC, or GC, or a vitrified grinding wheel. It may be formed from a bond wheel, a metal bond wheel, a resin bond wheel, or the like.

As described above, the ultrasonic vibrations generated from the ultrasonic vibrator 3 are amplified via the booster 4 and transmitted to the grinding tool 10. As a result, the cutting edge 11 ultrasonically vibrates in the tooth profile direction Y (see FIG. 3) with respect to the tooth surface W1 (see FIG. 3).

FIG. 3 is a diagram showing the direction in which the tooth surface W1 is ground by the cutting edge 11 of the grinding tool 10.
As shown in FIG. 3, the cutting edge 11 (see FIG. 2) moves the tooth surface W1, which is the processed surface of the workpiece W, in the tooth trace direction The tooth surface W1 is ground by ultrasonic vibration in the tooth profile direction Y with respect to the tooth surface W1.

That is, the cutting edge 11 of the rotating grinding tool 10 (see FIG. 2) vibrates ultrasonically in the tooth profile direction Y while moving the tooth surface W1 of the workpiece W in the tooth trace direction X. In other words, the cutting edge 11 of the grinding tool 10 grinds the tooth surface W1 while vibrating in the tooth profile direction Y and moving substantially in a wavy line shape in the tooth trace direction X. Note that the amplitude of the ultrasonic vibration of the cutting edge 11 is, for example, 2 to 50 μm, and the frequency is 15 to 50 kHz.

In this way, the cutting edge 11 of the rotating grinding tool 10 moves the tooth surface W1 in the tooth trace direction It becomes difficult to form. That is, due to the ultrasonic vibration in the tooth profile direction Y, a highly accurate tooth surface W1 with shallow grinding marks is formed without leaving deep grinding marks.

Referring to FIG. 2, a small diameter portion 13 having a smaller diameter than both end sides, that is, both end portions 15 and 16, is formed approximately at the center of the base metal 12 in the rotation axis direction. Thereby, the ultrasonic vibration of the cutting edge 11 becomes in a state suitable for tooth surface grinding. Therefore, highly accurate tooth surface grinding with fewer grinding streaks is possible.

Specifically, the small diameter portion 13 is formed in a substantially hyperboloid shape or a substantially arcuate shape. The base metal 12 having such a shape is particularly excellent in applying suitable ultrasonic vibrations to the cutting edge 11. More specifically, when ultrasonic vibration is used, the vibration becomes smaller as the diameter of the cutting edge 11 becomes larger. However, by optimizing the shape by forming a small diameter portion 13 in the shape of a substantially hyperbolic surface or a substantially circular arc surface on the base metal 12, accurate vibration in the tooth profile direction can be obtained even with a grindstone having a large diameter of the cutting edge 11. be able to.

Referring to FIGS. 1 to 3, since the small diameter portion 13 having a substantially hyperboloid shape or a substantially circular arc shape is formed at the substantially center of the base metal 12, the ultrasonic vibration from the ultrasonic transducer 3 can be The vibration is transmitted to one end 15 of the base metal 12 via the booster 4, and the vicinity of the one end 15 vibrates in the direction of the rotation axis.

At approximately the center of the base metal 12, that is, at approximately the center of the approximately hyperboloid-shaped or approximately arc-shaped small diameter portion 13, the vibration transmission in the direction of the rotation axis is improved by suppressing the amplitude in the radial direction due to Poisson's ratio. be done. Specifically, approximately the center of the approximately hyperboloid-shaped small diameter portion 13 becomes a vibration node where the vibration amplitude in the direction of the rotation axis is approximately 0.

Then, the vicinity of the cutting edge 11, that is, the vicinity of the other end 16 of the base metal 12, undergoes large ultrasonic vibrations in the direction opposite to the end 15 in synchronization with the vibration of the one end 15 along the rotation axis direction. The base metal 12 as a whole expands and contracts in the direction of the rotation axis. By forming the substantially hyperbolic small diameter portion 13 as described above, the ultrasonic vibration from the ultrasonic vibrator 3 is efficiently transmitted to the cutting edge 11.

In this manner, by forming the small diameter portion 13 approximately at the center of the base metal 12, ultrasonic vibrations can be efficiently transmitted to the cutting edge 11 in a suitable state. As a result, highly accurate and highly efficient grinding is performed, and a gear with excellent tooth surface properties is obtained.

Furthermore, oil pockets can be formed on the tooth surface W1 of the workpiece W by the grinding process in which suitable ultrasonic vibrations are applied to the cutting edge 11 as described above. Oil pockets are minute irregularities on the gear surface, or in other words, depressions.

By forming oil pockets on the tooth surface W1 after machining, the friction coefficient of the tooth surface W1 becomes smaller, resulting in excellent tooth surface properties with less noise and vibration, high strength, and high conformability and lubricity. You will get gears.

Further, since the cutting edge 11 moves in the tooth trace direction X and ultrasonically vibrates in the tooth profile direction Y with suitable strength, highly efficient gear grinding can be performed at a low circumferential speed.

At such low circumferential speed and low speed rotation, it is possible to perform the grinding process to form the precise tooth surface W1 with high efficiency. That is, conventionally 30,000r. p. m. Grinding processes that previously required high-speed rotation can now be performed with high precision at low-speed rotation.

Further, since gear grinding is possible at a low circumferential speed, highly accurate gear machining can be performed even if a small-diameter grinding tool 10 is used. For example, the cutting edge 11 of the grinding tool 10 may have a rotating diameter of 50 mm or less. By applying suitable ultrasonic vibrations, there is no need to increase the peripheral speed of the cutting edge 11, and even when the cutting edge 11 has a diameter of 50 mm or less, highly accurate tooth surface grinding is possible at low rotation speeds.

In this manner, the gear grinding device 1 eliminates the need for a large and complicated grinding device that rotates the grinding tool 10 at high speed. Therefore, productivity of gear manufacturing equipment and gears can be improved, and production costs can be reduced.

Next, with reference to FIGS. 4 and 5, the gear grinding device 101 will be described in detail as a modified example of the embodiment. Note that components that have the same or similar functions and effects as those of the already described embodiments are given the same reference numerals, and their explanations will be omitted.

FIG. 4 is a diagram showing a schematic configuration of the vicinity of the grinding tool 110 of the gear grinding device 101 according to another embodiment of the present invention.

Referring to FIG. 4, a gear grinding device 101 is a device that grinds, for example, parallel shaft gears such as spur gears and helical gears. The gear grinding device 101 includes a work shaft 6 that rotatably supports a work W, a grinding tool 110 as a gear grinding tool that grinds the work W, an ultrasonic oscillator 2, an ultrasonic vibrator 3, and a booster 4. , and a booster 5 as a second booster.

The work shaft 6 supports a work W to be machined, which is created as a gear. The work shaft 6 is connected to a drive motor (not shown) and rotatably supports the work W. The work shaft 6 may be configured to be tiltable and position changeable with respect to the rotation axis of the grinding tool 110.

The grinding tool 110 is supported by a column (not shown) having a feed mechanism (not shown), a drive motor, etc. (not shown), and generates gears from the work W while rotating. Specifically, the grinding tool 110 has a base metal 112 that has a substantially cylindrical shape and rotates about its central axis. The base metal 112 is formed with a cutting edge 111 that contacts the workpiece W while moving in the tooth trace direction X (see FIG. 3) of the workpiece W to grind the tooth surface W1 (see FIG. 3).

The base metal 112 has one end surface in the direction of the rotation axis, that is, an end 115, fixed to the booster 4, and the other end surface, that is, the end 116, fixed to the booster 5 as a second booster that amplifies ultrasonic vibrations. Fixed. The booster 5 is rotatably supported by a column (not shown). That is, the base metal 112 is rotatably supported at both ends 115 and 116 via the boosters 4 and 5.

Note that the grinding tool 110 may be provided so that its rotation axis extends substantially vertically, that is, in the vertical direction. Further, the work shaft 6 is in a twisted position with respect to the rotation axis of the grinding tool 110, and when the rotation axis of the grinding tool 110 is configured to be substantially perpendicular, the work shaft 6 extends substantially horizontally. It may be provided as follows.

FIG. 5 is a diagram showing the grinding tool 110 of the gear grinding device 101.
Referring to FIG. 5, a large diameter portion 14 having a larger diameter than both end portions 115 and 116 is formed approximately in the center of the base metal 112 of the processing tool in the direction of the rotation axis. The large diameter portion 14 has a substantially cylindrical shape. That is, the base metal 112 of the grinding tool 110 has a stepped, generally cylindrical shape with the large diameter portion 14 formed approximately in the center.

Referring to FIGS. 3 and 5, a cutting edge 111 is formed on the outer periphery of the large diameter portion 14. The cutting edge 111 contacts the workpiece W and grinds the tooth surface W1. The cutting edge 111 is formed into a substantially screw shape, and may be made of, for example, an electrodeposited wheel, a vitrified bond wheel, a metal bond wheel, a resin bond wheel, etc., having abrasive grains such as cBN, diamond, WC, or GC. It's okay. The cutting edge 111 moves relative to the tooth surface W1 of the workpiece W in the tooth trace direction X while rotating. As a result, the workpiece W is created into a parallel shaft gear with high precision, low noise, and low vibration.

Further, referring to FIG. 5, a cavity 17 is formed in the base metal 112 at the center of rotation. The cavity 17 is a hollow portion having a substantially circular cross section and extending in the direction of the rotation axis. That is, the base metal 112 has a hollow shape and is formed in a substantially circular tube shape. Since the cavity 17 is formed in the center of rotation of the base metal 112, the ultrasonic vibration of the cutting edge 111 is a vibration in the radial direction of the base metal 112, which is suitable for grinding.

Specifically, referring to FIGS. 4 and 5, ultrasonic vibrations generated from the ultrasonic vibrator 3 in the rotational axis direction are amplified by the booster 4 and transmitted to the end 115 of the base metal 112 of the grinding tool 110. be done. A booster 5 as a second booster is connected to the other end 116 of the base metal 112, and the vibration on the end 116 side is amplified by the booster 5. One end 115 and the other end 116 synchronously vibrate ultrasonically in opposite directions of the rotation axis. That is, the base metal 112 expands and contracts in the direction of the rotation axis.

The large diameter portion 14 at the approximate center of the base metal 112 repeatedly expands and contracts in the radial direction due to ultrasonic vibration, and the cutting edge 111 formed on the large diameter portion 14 ultrasonically vibrates in the radial direction. . That is, the cutting edge 111 vibrates ultrasonically in the tooth trace direction Y of the tooth surface W1 of the workpiece W (see FIG. 3) while moving in the tooth trace direction X of the tooth surface W1 of the workpiece W due to the rotation of the grinding tool 110.

In other words, the cutting edge 111 of the grinding tool 110 moves in the tooth trace direction X in a substantially wavy line shape while swinging in the tooth profile direction Y, and grinds the tooth surface W1. As a result, a highly accurate tooth surface W1 is formed on the workpiece W, where the grinding streaks are canceled out and the surface becomes shallow.

As mentioned above, since the center part of the base metal 112 is formed in the shape of a gap, vibrations in the direction of the rotation axis of both ends 115 and 116 of the base metal 112 are transmitted to the approximate center of the base metal 112, and are transmitted to the cutting edge 111. In this case, radial vibration suitable for grinding the workpiece W is generated. Thereby, highly accurate grinding can be performed with high efficiency, and a gear with high accuracy and excellent tooth surface roughness can be obtained.

With the above-described configuration including the booster 4 and the booster 5, it is possible to generate radial vibrations in the cutting edge 111. However, as the diameter of the cutting edge 111 becomes smaller, the vibration becomes smaller, and it becomes difficult to obtain suitable vibration, that is, large vibration. In this embodiment, since the cavity 17 is formed at the center of rotation of the base metal 112, vibration can be optimized according to the diameter of the cutting edge 111. That is, the same vibration can be obtained regardless of the diameter of the cutting edge 111.

Furthermore, oil pockets can be formed on the tooth surface W1 of the workpiece W by the grinding process in which suitable ultrasonic vibrations are applied to the cutting edge 111 as described above. As a result, a gear with excellent tooth surface properties, such as a small friction coefficient of the tooth surface W1, low noise and vibration, high strength, and high conformability and lubricity, can be obtained.

Further, since the cutting edge 111 moves in the tooth trace direction X and ultrasonically vibrates in the tooth profile direction Y with suitable strength, highly efficient gear grinding can be performed at a low circumferential speed.

At such low circumferential speed and low rotation speed, it is possible to perform grinding operations similar to conventional grinding wheels. That is, conventionally 30,000r. p. m. Grinding processes that previously required high-speed rotation can now be performed with high precision at low-speed rotation.

Furthermore, since gear grinding at low circumferential speed is possible, highly accurate gear machining can be performed even if a small-diameter grinding tool 110 is used. For example, the cutting edge 111 of the grinding tool 110 may have a rotating diameter of 50 mm or less. By applying suitable ultrasonic vibrations, there is no need to increase the circumferential speed of the cutting edge 111, and even when the cutting edge 111 has a diameter of 50 mm or less, highly accurate gear grinding is possible at low rotation speeds.

In this manner, the gear grinding device 101 eliminates the need for a large and complicated grinding device that rotates the grinding tool 110 at high speed. Therefore, productivity of gear manufacturing devices and gears can be improved, and production costs can be reduced.

Note that the present invention is not limited to the above-described embodiments, and various other modifications can be made without departing from the gist of the present invention.

1, 101 Gear grinding device 2 Ultrasonic oscillator 3 Ultrasonic vibrator 4 Booster 4a End part 4b End part 5 Booster 6 Work shaft 10, 110 Grinding tool 11, 111 Cutting edge 12, 112 Base metal 13 Small diameter part 14 Large diameter part 15 , 115 End portions 16, 116 End portion 17 Cavity W Workpiece W1 Tooth surface X Tooth trace direction Y Tooth profile direction

Claims (6)

A work shaft that rotatably supports the work,
a grinding tool whose cutting edge moves in the tooth trace direction while rotating to grind a tooth surface on the workpiece;
an ultrasonic vibrator that generates ultrasonic vibrations in the rotational axis direction of the grinding tool by output from an ultrasonic oscillator;
a booster that connects the ultrasonic vibrator and the grinding tool to amplify the ultrasonic vibration,
The cutting edge vibrates ultrasonically in the tooth profile direction with respect to the tooth surface ,
A gear grinding device characterized in that the base metal of the grinding tool has a small diameter portion formed in the center in the direction of the rotation axis, the diameter being smaller than both ends . The base metal has one end surface in the direction of the rotation axis fixed to the booster, and the other end surface has the cutting edge formed therein,
The gear grinding apparatus according to claim 1, wherein the workpiece is a bevel gear. The gear grinding device according to claim 1 or 2 , wherein the small diameter portion is formed in a hyperboloid shape. A work shaft that rotatably supports the work,
a grinding tool whose cutting edge moves in the tooth trace direction while rotating to grind a tooth surface on the workpiece;
an ultrasonic vibrator that generates ultrasonic vibrations in the rotational axis direction of the grinding tool by output from an ultrasonic oscillator;
a booster that connects the ultrasonic vibrator and the grinding tool to amplify the ultrasonic vibration,
The cutting edge vibrates ultrasonically in the tooth profile direction with respect to the tooth surface ,
The base metal of the grinding tool has a large diameter portion formed in the center in the direction of the rotation axis, the diameter being larger than both ends,
One end surface of the base metal in the direction of the rotation axis is fixed to the booster, and the other end surface is fixed to a second booster that amplifies the ultrasonic vibration,
A cavity is formed in the rotation center of the base metal during gear grinding,
The cutting edge is formed in a screw shape on the outer periphery of the large diameter portion,
A gear grinding device characterized in that the workpiece is a parallel shaft gear . A gear grinding tool used in a gear grinding device having an ultrasonic vibrator,
a base metal that rotates with one end face fixed to a booster connected to the ultrasonic vibrator;
a cutting edge that is provided on the base metal and moves the processed surface of the workpiece in the tooth trace direction to grind the tooth surface of the workpiece;
The cutting edge ultrasonically vibrates in the tooth profile direction with respect to the tooth surface by ultrasonic vibrations oscillated from the ultrasonic vibrator and amplified by the booster,
A gear grinding tool characterized in that the base metal has a small diameter portion formed at the center in the direction of the rotation axis, the diameter being smaller than that at both ends. A gear grinding tool used in a gear grinding device having an ultrasonic vibrator,
a base metal that rotates with one end face fixed to a booster connected to the ultrasonic vibrator;
a cutting edge that is provided on the base metal and moves the processed surface of the workpiece in the tooth trace direction to grind the tooth surface of the workpiece;
The cutting edge ultrasonically vibrates in the tooth profile direction with respect to the tooth surface by ultrasonic vibrations oscillated from the ultrasonic vibrator and amplified by the booster,
The base metal has a large diameter portion formed in the center in the direction of the rotation axis, the diameter being larger than both ends ,
One end surface of the base metal in the direction of the rotation axis is fixed to the booster, and the other end surface is fixed to a second booster that amplifies the ultrasonic vibration,
A cavity is formed in the rotation center of the base metal during gear grinding,
The cutting edge is formed in a screw shape on the outer periphery of the large diameter portion,
A gear grinding tool , wherein the workpiece is a parallel shaft gear .

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