JPH09241737A - Method for highly strengthening gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely improve the roughness of surface and the fatigue strength and to efficiently and surely remove glass bead waste stuck to the surface of a gear. SOLUTION: Jet flow 22 of the glass beads 20 and water 18 is sprayed from a nozzle 72 toward the surface of the gear 12 after heat treatment and compressive residual stress is given to the gear 12 and also, grinding of the gear 12 is executed by crushing the glass beads 20. Successively, only the water 18 is sprayed toward the surface of the gear 12 and the surface of the gear 12 is quickly and efficiently washed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for increasing the strength of a gear for increasing the strength of the gear surface.

[0002]

2. Description of the Related Art Normally, a gear is repeatedly subjected to a load during use, and it is necessary to increase the fatigue strength of the gear surface. Therefore, hitherto, shot peening has been widely performed in which a steel ball or the like is collided with the gear surface to give a compressive residual stress.

However, in this type of shot peening, since steel balls are used as a shot material, the gear surface is roughened and the surface roughness is lowered. Therefore, for example, as disclosed in Japanese Examined Patent Publication No. 5-21711, the surface of a metal molded product is quenched, and then the metal surface is ground.
A method for strengthening a metal surface by projecting glass beads of m to 0.6 mm is known. This is intended to improve the fatigue strength without roughening the metal surface.

[0004]

However, in the above-mentioned prior art, the compressive residual stress applied is lowered and the fatigue strength cannot be improved to a desired value, and the directivity of the projected glass beads is also increased. It has been pointed out that the efficiency is remarkably reduced due to the poor performance.

Further, since the glass beads are crushed on the gear surface, fine glass bead dust is generated, and the fine glass bead dust is easily attached to the gear surface. Therefore, in order to remove the glass bead waste from the gear surface, it is necessary to separately provide a cleaning step, and there is a problem that the entire work for strengthening the gear cannot be efficiently performed.

The present invention solves this kind of problem, and it is possible to surely improve the surface roughness and the fatigue strength, and to efficiently and surely remove the glass bead waste adhering to the gear surface. An object of the present invention is to provide a method for increasing the strength of a simple gear.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a jet flow of glass beads and a liquid is projected onto the gear surface to impart a compressive residual stress to the gear and to cause the gear surface to move. The glass beads are crushed and the gear is polished. As a result, the glass beads collide with the gear with directivity, and the jet flow of the glass beads and the liquid,
It effectively functions to strengthen and polish the gear.

Next, when only the liquid is projected onto the surface of the gear after polishing, the glass bead scraps made of fine powder adhering to the surface of the gear are washed and removed by the liquid.
Therefore, only by stopping the supply of the glass beads, the cleaning work of the gear surface can be quickly carried out, and the entire work for strengthening the gear can be carried out efficiently and easily.

At the same time, the glass beads in the nozzle are surely sucked out by the negative pressure generated when the liquid is projected, and the nozzle is not clogged due to the residual glass beads.

Further, in the cleaning step, by spraying only the liquid on the gear surface while rotating the gear alternately in the forward rotation direction and the reverse rotation direction, the cleaning performance of the gear surface is further improved. Furthermore, by spraying only the liquid on the gear surface while moving the nozzle with respect to the gear, the cleaning property of the gear surface can be similarly improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial cross-sectional front view of a strengthening device 10 according to a first embodiment for carrying out a method for strengthening a gear of the present invention, and FIG. FIG. 3 is a side view of a partial cross-section of the strengthening device 10.

The device 10 for strengthening strength has a gear holding mechanism 16 for holding a gear 12 as an object to be processed and positioning and holding the gear 12 in a chamber 14a in a casing 14, a liquid such as water 18 and glass beads. 20 and a jet mechanism 24 for projecting a jet flow 22 toward the gear 12, and a water supply mechanism 26 for pumping the water 18 to the projection mechanism 24.
And a glass bead supply mechanism 28 for feeding the glass beads 20 to the projection mechanism 24 by a predetermined amount.

The gear holding mechanism 16 is, as shown in FIG.
An X-axis slide unit 30 and a spindle unit 32 mounted on the base 29 are provided. The X-axis motor 34 constituting the X-axis slide unit 30 is attached to the ball screw 36.
And the pair of guide bars 3 are connected to the ball screw 36.
8 are arranged in parallel, and the spindle unit 32 is provided via the ball screw 36 and the guide bar 38.
Are supported so that they can move back and forth in the direction of arrow X.

The spindle unit 32 has a spindle 42 connected to a spindle motor 40, and the gear 12 is mounted on the tip of the spindle 42. The tip end side of the spindle unit 32 can be inserted into the casing 14 through an opening 44 formed in the side wall of the casing 14.

As shown in FIG. 2, the projection mechanism 24 comprises a Y-axis slide unit 46 and a Z-axis slide unit 48. The Y-axis slide unit 46 has a Y-axis motor 50 oriented in the horizontal direction, and via a ball screw 52 connected to the Y-axis motor 50 and a pair of guide bars 54 parallel to the ball screw 52, The Z-axis slide unit 48 can move back and forth in the arrow Y direction. The moving body 62 is moved in the arrow Z direction via a ball screw 58 extending vertically downward from the Z-axis motor 56 forming the Z-axis slide unit 48 and a pair of guide bars 60 parallel to the ball screw 58. You can move back and forth freely.

A tube body 66 is attached to the tips of a pair of support rods 64 extending from the moving body 62 in the arrow Y direction and oriented in the arrow Z direction. An opening / closing valve 68 for turning on / off the introduction of the water 18 is provided at an upper portion of the pipe body 66, and a mixing chamber for mixing the glass beads 20 with the water 18 is provided at a lower portion of the pipe body 66. 70 is connected to the bottom of the mixing chamber 70.
2 are provided.

The water supply mechanism 26 has a water pipe line 74 connected to the inlet side of the opening / closing valve 68. The water pipe line 74 is spirally wound inside the casing 14 and then is provided outside the casing 14. It is connected via a joint 76 (see FIG. 1). A high pressure pump (not shown) is connected to the joint 76, and the high pressure pump is set to project the jet flow 22 toward the gear 12 at a predetermined injection pressure.

The glass bead supply mechanism 28 includes a hopper 80 which is held on the upper surface of the casing 14 via a mounting base 78. At the bottom of the hopper 80, the hopper 8
A load cell 82 for detecting the remaining amount of the glass beads 20 in 0 is arranged.

As shown in FIG. 1, on the outlet side of the hopper 80, a metering valve 84, a negative pressure meter 86 and a laser flow meter 88 are connected so as to be oriented vertically downward. Pipeline 90
Has one end connected to the laser flow meter 88 and the other end inserted into the chamber 14a in the casing 14 and connected to the mixing chamber 70. The glass beads 20 stored in the hopper 80 have a diameter of 0.05 mm.
It is set to 0.3 mm.

A mist collecting mechanism 92 is placed on the base 29. The tip ends of the pair of ducts 94 and 96 that form the mist collecting mechanism 92 are inserted into the chamber 14a from the side of the casing 14 and are arranged between the gear 12 and the nozzle 72 and close to the gear 12. ing.

On the lower side of the casing 14, there is integrally provided a conical portion 98 which is directed downward and has a reduced diameter. Below the lower opening of the conical portion 98, a drainage conveyor 100 is provided. It is arranged.

The operation of the strengthening apparatus 10 thus constructed will be described below in connection with the strengthening method.

First, carburizing and quenching is performed on the gear 12 that has been gear-cut by cutting. And
The gear 12 after the carburizing and quenching treatment is set on the spindle 42 that constitutes the gear holding mechanism 16, while the projection mechanism 24
The nozzle 72 constituting the above is selectively position-adjusted in the arrow Y direction and the arrow Z direction via the Y-axis slide unit 46 and the Z-axis slide unit 48, and is arranged corresponding to the gear 12.

Therefore, the gear 12 rotates in a predetermined direction integrally with the spindle 42 via the spindle motor 40, and the gear 12 moves through the X-axis motor 34 constituting the X-axis slide unit 30. And moves in the direction of arrow X1 integrally with (see FIG. 1).

At this time, the projection mechanism 24 is driven, and the water 18 is pressure-fed from the pipe 66 to the mixing chamber 70 through the water pipe 74 under the action of a high-pressure pump (not shown). On the other hand, the metering valve 8 constituting the glass bead supply mechanism 28
4 is driven, and the mixing chamber 7 is fed from the hopper 80.
A predetermined amount of glass beads 20 is fed to the container 0 through the pipe line 90. Therefore, when the water 18 is jetted from the nozzle 72, a negative pressure is generated in the mixing chamber 70, and the glass beads 20 in the pipe line 90 mix with the water 18 to form a jet flow 22 from the nozzle 72. It is projected on the gear 12.

Therefore, the jet flow 22 of the water 18 and the glass beads 20 has directivity, and the tooth tip 102 of the gear 12 and the tooth surface 10 are directed.
4 and the desired position of the root 106 are accurately collided (see FIGS. 3A to 3C).

Here, the module is 1.5 and the twist angle is 3
The jet 12 is projected at 18 ° to the portion corresponding to the reference pitch circle (PCD) of the tooth surface 104 by using the gear 12 set to 6 °, the pressure angle of 17.5 °, and the number of teeth of 52. As a result, the jet flow 22 can be reliably projected onto the tooth surface 104 and the tooth root 106 of the gear 12, and the tooth surface 104
And, it becomes possible to give a sufficient compressive residual stress to the root 106.

Further, as shown in FIG. 4, when the glass beads 20 collide with the tooth surface 104 of the gear 12, this tooth surface 1
The surface of No. 04 is given a compressive residual stress via the glass beads 20 and is polished, and the glass beads 20 are crushed. At that time, the crushed pieces 20a are
The water 18 jetted toward the tooth surface 104 presses the surface of the tooth surface 104 at an acute angle. Therefore, the gear 12 has an effect that at least the portion corresponding to the reference pitch circle of the tooth surface 104 is subjected to the polishing process from the tooth root 106 to be surely processed into a smooth surface.

5A is an enlarged view of the tooth flank 104 after the gear 12 is carburized and quenched, and FIG. 5B is
An enlarged view of the tooth flank 104 after the gear 12 has been strengthened by the strengthening device 10 is shown. 6A shows an enlarged view of the tooth bottom after the carburizing and quenching treatment, and FIG. 6B shows an enlarged view of the tooth bottom subjected to the strengthening treatment by the strengthening device 10. As a result, the tooth surface 1
It was found that the surface of No. 04 and the tooth root were smoothed while the oxide layer was effectively removed by the strengthening treatment.

The jet 22 is projected from the nozzle 72 and the gear 1
When subjecting 2 to the strengthening treatment, crushed fine glass bead dust floats in the chamber 14a. Therefore, by driving the mist collecting mechanism 92, the chamber 14
A pair of ducts 9 for removing fine glass bead dust floating in a
It can be surely collected by suction from 4, 96. Further, the pieces of water 18 and the glass beads 20 jetted into the chamber 14 a are discharged into the drainage conveyor 100 from the conical portion 98 provided in the lower portion of the casing 14, and the drainage conveyor 100 is used. Be collected outside.

As described above, the gear 12 is connected to the spindle 4
The gear 12 is moved in the direction of the arrow X1 while rotating integrally with the gear 2, and the jet flow 22 is projected to increase the strength of the gear 12.
As shown in FIG. 4, crushed pieces 20a and the like generated by crushing the glass beads 20 are likely to adhere to the surface of the.

Therefore, in the first embodiment, the X-axis motor 34 constituting the X-axis slide unit 30 is driven in the opposite direction to the above, the spindle unit 32 moves in the arrow X2 direction, while the glass bead supply mechanism. The metering valve 84 constituting 28 is closed and the supply of the glass beads 20 from the hopper 80 to the projection mechanism 24 is stopped.
Therefore, the gear 12 after polishing is rotated by the arrow X2.
While moving in the direction, only the water 18 is projected and the crushed pieces 20a and the like adhering to the surface of the gear 12 are cleaned.

As described above, the projection mechanism 24 functions as a cleaning mechanism only by stopping the supply of the glass beads 20 from the glass bead supply mechanism 28. Therefore, the cleaning work of the surface of the gear 12 after polishing can be performed substantially continuously immediately after the strengthening treatment work is completed, and the cleaning work is rapidly performed to enhance the strengthening treatment of the gear 12. The effect is that the entire work is efficiently and easily performed.

Moreover, the glass beads 20 remaining in the conduit 90 are reliably sucked out by the negative pressure generated when the water 18 is projected from the nozzle 72. For this reason,
It is possible to reliably prevent the glass beads 20 from remaining in the nozzle 72 and causing clogging or the like.

By the way, during the cleaning operation of the gear 12, by driving the gear 12 and / or the nozzle 72 in various directions, the cleaning performance of the gear 12 can be further improved. For example, as shown in FIG. 7, the gear 1
2 through a spindle unit 32 and a spindle 42
Only the water 18 is projected from the nozzle 72 to the gear 12 while rotating alternately with the arrow A direction (forward rotation direction) and the arrow B direction (reverse rotation direction) integrally with.

Further, as shown in FIG.
To the gear 12 that rotates in the direction of arrow A integrally with
Only the water 18 is projected from the nozzle 72 toward the gear 12 while moving the nozzle 72 in the arrow Y1 direction and / or the arrow Y2 direction. At that time, the nozzle 72
Is moved in the arrow Y direction by driving and controlling the Y-axis slide unit 46.

Furthermore, as shown in FIG. 9, the gear 12
Is rotated integrally with the spindle 42 in the direction of arrow A,
Further, while the nozzle 72 is displaced back and forth in the arrow Z direction via the Z-axis slide unit 48, only the water 18 is projected from the nozzle 72 toward the gear 12. In order to improve the cleaning performance of the gear 12, various methods such as selectively combining the operations of FIGS. 7 to 9 can be considered.

Next, FIGS. 10 and 11 show a projection mechanism 120 constituting a high strength device according to a second embodiment of the present invention. The same components as those of the projection mechanism 24 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The projection mechanism 120 includes a support plate 122 fixed to the tips of the pair of support rods 64, and a swing motor 124 is fixed to the support plate 122. The tubular body 66 is attached to the rotary drive shaft 126 of the turning motor 124 via a rotary member 128.

In the projection mechanism 120 having the above-described structure, when the gear 12 is washed, the tubular body 66 is integrally formed with the rotating member 128 via the rotary drive shaft 126 under the driving action of the turning motor 124. Only water 18 is projected from the nozzle 72 onto the gear 12 while reciprocating within the angular range (see FIG. 11). As a result, the cleaning water 18 is projected onto the gear 12 from various directions, and the cleaning efficiency of the gear 12 is further improved.

Further, as shown in FIG. 12, while the nozzle 72 is translated in the tooth thickness direction of the gear 12 (arrow X ₁ direction and arrow X ₂ direction), only the water 18 is fed from the nozzle 72 to the gear 12. You may project.

[0042]

As described above, in the method for strengthening the strength of the gear according to the present invention, the jet stream of the glass beads and the liquid is projected on the surface of the gear to impart the compressive residual stress to the gear, and at the surface of the gear. The glass beads are crushed and the gear is polished. As a result, the glass beads collide with the gear with directivity, and the jet flow of the glass beads and the liquid effectively functions to strengthen and polish the gear.

Next, when only the liquid is projected onto the surface of the gear after polishing, the glass bead scraps made of fine powder adhering to the surface of the gear are washed and removed by the liquid.
Therefore, it suffices to stop the supply of the glass beads, the cleaning work of the gear surface is quickly performed, and the entire work for strengthening the gear is efficiently and easily performed.

Further, the glass beads in the nozzle are surely sucked by the negative pressure generated when the liquid is projected, so that the nozzle is not clogged due to the residual glass beads.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional front explanatory view of a strength-enhancing device according to a first embodiment for carrying out a gear strength-enhancing method of the present invention.

FIG. 2 is a partial cross-sectional side view diagram of the strengthening device.

FIG. 3 is a diagram for explaining the operation of the strength-enhancing device,
3A is an explanatory diagram of a tooth tip processing state, FIG. 3B is an explanatory diagram of a tooth surface processing state, and FIG. 3C is an explanatory diagram of a tooth root processing state.

FIG. 4 is an explanatory diagram when glass beads collide with a tooth surface.

5A and 5B are explanatory views before and after processing by the strengthening device, FIG. 5A is an enlarged view of a portion corresponding to a reference pitch circle after carburizing and quenching processing, and FIG. 5B is a strengthening processing. It is an enlarged view of a portion corresponding to a reference pitch circle.

6A and 6B are explanatory views before and after the treatment by the strengthening device, FIG. 6A is an enlarged view of the tooth bottom after the carburizing and quenching treatment, and FIG. 6B is a diagram after the strengthening treatment. It is an enlarged view of a tooth bottom.

FIG. 7 is an operation explanatory diagram when rotating a gear in both forward and reverse directions during cleaning.

FIG. 8 is an operation explanatory diagram when moving the nozzle back and forth during cleaning.

FIG. 9 is an operation explanatory diagram when moving the nozzle up and down during cleaning.

FIG. 10 is a perspective explanatory view of a projection mechanism that constitutes the high strength device according to the second embodiment.

11 is a front explanatory view of the projection mechanism of FIG.

FIG. 12 is an operation explanatory diagram when the nozzle is translated in the tooth thickness direction of the gear during cleaning.

[Explanation of symbols]

10 ... Strengthening device 12 ... Gear 14 ... Casing 16 ... Gear holding mechanism 18 ... Water 20 ... Glass beads 22 ... Jet 24, 120 ... Projection mechanism 26 ... Water supply mechanism 28 ... Glass bead supply mechanism 30 ... X-axis slide unit 32 ... Spindle unit 42 ... Spindle 46 ... Y-axis slide unit 48 ... Z-axis slide unit 66 ... Tube body 70 ... Mixing chamber 72 ... Nozzle 74 ... Water pipeline 80 ... Hopper 90 ... Pipeline 92 ... Mist collecting mechanism 124 ... Swivel motor

Claims (3)

[Claims] 1. A method for increasing the strength of a gear for increasing the strength of the gear surface, which comprises jetting a jet of glass beads and a liquid from a nozzle toward the gear surface after heat treatment. A step of grinding the gear by crushing the glass beads on the gear surface while applying a compressive residual stress to the gear surface, and by projecting only the liquid toward the gear surface after the grinding, A method of increasing the strength of a gear, comprising: a step of cleaning the surface. 2. The high strength method according to claim 1, wherein in the cleaning step, only the liquid is projected onto the surface of the gear while the gear is alternately rotated in the forward rotation direction and the reverse rotation direction. Method for strengthening gears. 3. The gear according to claim 1 or 2, wherein in the cleaning step, only the liquid is projected onto the gear surface while moving the nozzle with respect to the gear. Strengthening method of.