JP2007247832A - Gear, gearing assembly, and tooth face strength improving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear, a gearing assembly and a tooth face strength improving method. <P>SOLUTION: Minute scale-like burrs 2 are provided on a tooth face 1 in random directions. The burrs 2 grind the protrusions of the other tooth face 1, smooth the tooth face 1 to improve the conformability of the tooth face 1, and suppress separation damages to improve the strength of the toot face 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gear, a meshing assembly, and a tooth surface strength improving method for improving tooth surface strength.

  In general, gears are coated with various materials such as copper, molybdenum disulfide, PTFE Teflon (registered trademark), etc., to improve the tooth surface properties in order to improve the tooth surface strength. There is.

Another means of improving the tooth surface strength is to improve the tooth surface strength by creating micro dimples on the tooth surface by shot peening treatment in which hard particles collide with the object at high speed. (For example, refer to Patent Document 1).
JP 2005-201295 A

  However, when the tooth surface is coated, there are problems that the manufacturing cost increases and the strength of the tooth surface cannot be improved in a state where the adhesion between the tooth surface and the coating material is poor. In addition, when creating micro dimples on the tooth surface, there is a risk that micro cracks will form at the roots of the micro dimples, and when micro cracks occur, large pits will occur as the tooth surface engages. There is a problem that the tooth surface peeling damage called pitching or spalling occurs.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gear, a meshing assembly, and a tooth surface strength improving method for improving tooth surface strength so as to suppress peeling damage.

  The present invention relates to a gear having a minute scaly ridge on the tooth surface in a random direction.

  In the present invention, it is preferable that the scaly whip is formed by a texture in which undulations having a pitch of about several μm to about 100 μm are randomly layered.

  In the present invention, it is preferable that the scaly crust is formed by a texture in which several undulations and 40 to 100 μm undulations are layered.

  In the present invention, it is preferable that at least the meshing surface of the tooth surface is formed by eliminating the processing eye of the gear by the texture.

  The present invention relates to a meshing assembly configured so that the tooth surfaces of a pair of gears mesh with each other, wherein the gear assembly of the present invention is provided on at least one of the meshing tooth surfaces.

  The present invention provides a tooth surface strength characterized in that fine and hard particles collide with a tooth surface of a gear at a high speed to form minute scaly ridges on the tooth surface in a random direction. It relates to the improvement method.

  According to the gear and the meshing assembly of the present invention, since the fine scaly ridges are provided in a random direction with respect to the tooth surface, the tooth surface is made smooth by scraping the protrusion on the other tooth surface with the blade. The conformability of the surface can be improved, and as a result, the strength of the tooth surface can be improved so as to suppress peeling damage.

  According to the tooth surface strength improving method of the present invention, fine and hard particles collide with the tooth surface of the gear at high speed, so that a minute scaly ridge facing the tooth surface of the gear in a random direction. It can be formed easily.

  As described above, according to the present invention, since the minute scaly ridges are provided in a random direction with respect to the tooth surface, the tooth surface is improved so as to improve the conformability of the tooth surface and suppress peeling damage. It is possible to achieve an excellent effect that the strength of the can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 6 show a gear, meshing assembly, and tooth surface strength improving method according to an embodiment of the present invention.

  The gear is provided with minute scaly rolls 2 in a random direction with respect to the tooth surface 1, and the scaly rolls 2 have a texture (texture) in which undulations with a pitch of about several μm to about 100 μm are layered in the surface direction. And a surface pattern), specifically, a texture in which fine waviness of several μm and large waviness of 40 to 100 μm are overlaid. Here, the configuration of the gear is not particularly limited as long as it transmits power to the other member via the tooth surface 1, and is a helical gear, a spur gear, an internal gear, a rack, or a quick bevel gear. Any of a bevel gear, a screw gear, a worm gear, a hypoid gear, and the like may be used.

  The meshing assembly (meshing assembly) includes at least a pair of gears by appropriately combining various gears, and includes a gear having the above-described minute scaly barb 2 on at least one of the meshing tooth surfaces 1. It is. Here, the configuration of the meshing assembly is not particularly limited as long as power is transmitted from one gear to the other gear via the tooth surface 1, and any configuration may be used.

  Specifically, an example of a gear is a helical gear with a module 3.5 and a helix angle of 23 °. After gear cutting a steel material (SCM420H), gas carburizing and quenching is performed, and the tooth surface 1 is ground. Then, a gear is prepared and processed by the method for improving the tooth surface strength.

  The method of improving the tooth surface strength is a two-stage peening process in which fine particle peening treatment for causing fine and hard particles to collide with the tooth surface 1 of the gear at a high speed is performed in two different stages continuously. The peening treatment of the eyes is a direct pressure air type with respect to the gear, and the projection pressure is 0.4 to 0.69 MPa, preferably 0.4 to 0.6 MPa, and the arc height 0.2 to 0.5 mm (N scale), preferably Under the conditions of 0.24 to 0.41 mm (N scale) and coverage of 200%, a shot particle having a material SKH, a center particle size of 70 to 150 μm, preferably 80 to 130 μm, and a hardness of 700 to 1000 Hv, preferably 750 to 800 Hv is projected. In the second stage peening process, the projection pressure is 0.3 to 0.69 MPa, preferably 0.4 MPa, the arc height is 0. Under the conditions of 07-0.2 mm (N scale), preferably 0.07 mm (N scale) and coverage of 200%, the material is SKH, the center particle size is 20-70 μm, preferably 50 μm, and the hardness is 700-1000 Hv, preferably 750-800 Hv. The shot grains are projected and processed, and finally, a fine scaly crush (a planar cleavage portion with a finely split tip) is formed in a random direction with respect to the tooth surface 1 of the gear. Here, the fine particle peening treatment may be performed by one-stage peening.

  As a result, when the tooth surface 1 before and after the treatment by the tooth surface strength improving method is observed and compared with a scanning electron microscope, the tooth surface 1 before the treatment has a grinding eye, a shaving eye, etc. as shown in FIG. In the tooth surface 1 after the treatment, the minute scaly (planar) 2 is directed toward the random direction so that the gear finishes disappear completely as shown in FIG. Is forming. Here, the scaly scissors 2 are formed by projecting fine shot grains at a high speed in the fine particle peening process, so that the surface of the tooth surface 1 becomes a temperature higher than the transformation point of the steel and the extreme surface layer is melted. It is thought that it is obtained by rapid air cooling. Further, among the fine scaly whiskers 2, a fine swell of several μm is considered to be a trace that the shot grain rubs the tooth surface 1, and a large swell of 40 to 100 μm is a plastic deformation trace that the shot grain collides with. it is conceivable that.

  When driving using a gear having a small scaly scissors 2 in a random direction, the edge 3 of the scissors 2 scrapes the projection of the other tooth surface 1 with respect to the gear of the other object. Thus, the tooth surface 1 is smoothed to improve the conformability of the tooth surface 1. Here, in the gear and the meshing assembly, when one of the meshing tooth surfaces 1 is provided with a minute scaly barb 2, the projection of the other tooth surface 1 is scraped, and both of the meshing tooth surfaces 1 are minute. In the case where the scaly barb 2 is provided, the projections and the like of the other tooth surface 1 are scraped off.

  In the following, the gear strength is measured and the tooth surface roughness is measured for the gear provided with the fine scaly whip 2 in the random direction and the gear of the comparative example, and the comparison is shown respectively.

  The gear strength is measured under the conditions of a gear rotation speed of 1500 rpm, an oil temperature of 90 ° C., and an oil amount of 1.2 L / min (lubricating oil is a transmission oil for large automobiles). The durability operation was performed until the tooth surface 1 was peeled and damaged. The familiar operation is a state in which the protrusions (roughness) on the surface of the tooth surface 1 due to the machining eyes are worn and become smooth with the operation, and some of the protrusions are rooted with the wear. There is a case where a minute crack is generated in the portion, and peeling damage of the tooth surface 1 called pitting or spalling is caused as in the present invention.

  On the other hand, the gear of the comparative example is based on the impeller type shot peening process, and the material SC and the grain are formed under the conditions of a projection speed of 62 m / s, an arc height of 0.35 (A scale), and a coverage of 200%. Shot particles having a diameter of 800 μm and a hardness of 560 Hv are projected and processed. In addition, when the tooth surface 1 by the impeller type shot peening process is observed and compared with a scanning electron microscope, the tooth surface 1 before the process is partially crushed by shot grains while the processed surface is It is something that remains clear.

  As a result of the endurance operation, it was clear that the gear strength provided with the minute scaly barbs 2 in the random direction has improved gear strength as compared with the gear of the comparative example of impeller type shot peening.

  As a result of the measurement of the tooth surface roughness, the gear provided with the minute scaly ridges 2 in the random direction shows that the tooth surface 1 is not processed as shown in FIG. Or, it becomes rougher than the comparative example of impeller type shot peening, and in the case of a short time after the start of operation, the tooth surface 1 is a protrusion of the other tooth surface 1 at the edge 3 of the scissors 2 of one tooth surface 1. As shown in FIG. 6, it was clear that the other tooth surface 1 was smoother than that of the comparative example.

  Further, when the tooth surface 1 after the processing of the gear provided with the fine scaly-shaped ridge 2 in the random direction and the gear of the comparative example of the impeller shot peening is observed and compared with a scanning electron microscope, the visual damage is observed. However, in the gear of the comparative example, a large number of pits were generated along the processed lines, and there was an indication that these pits were connected and grew greatly. On the other hand, in the gear provided with the minute scaly whip 2 in the random direction, minute pits are generated, but the appearance of growing by connecting these pits was not recognized.

  In another comparative method, the residual stress on the tooth surface 1 is given a larger residual compressive stress in the vicinity of the surface than in the comparative example so that the maximum value is obtained at a depth of about 10 μm in a relatively shallow region from the surface. In addition, in the X-ray half-width of the tooth surface 1, the half-value width that varies depending on the size of the crystal grains and the local non-uniformity of the microscopic strain is in the region of the tooth surface depth of 5 to 40 μm. It was getting smaller.

  As described above, according to the gear and the meshing assembly of the present embodiment, since the minute scaly scissors 2 are provided in a random direction with respect to the tooth surface 1, the edge 3 of the scissors 2 has the other tooth surface 1. By shaving the protrusion, the tooth surface 1 can be smoothed to improve the conformability of the tooth surface 1, and as a result, the strength of the tooth surface 1 can be improved so as to suppress peeling damage.

  When the scaly scissors 2 are formed by a texture in which undulations of about several μm to about 100 μm pitch are randomly layered, the protrusions of the other tooth surface 1 are appropriately shaved by the edges 3 of the scissors 2 The tooth surface 1 can be smoothed, the conformability of the tooth surface 1 can be easily improved, and the strength of the tooth surface 1 can be further improved.

  The scaly scissor 2 is formed by a texture in which several μm of undulation and 40-100 μm of undulation are layered, and by appropriately shaving the projection of the other tooth surface 1 at the edge 3 of the crust 2, The tooth surface 1 can be smoothed to easily improve the conformability of the tooth surface 1, and the strength of the tooth surface 1 can be further improved.

  If at least the meshing surface of the tooth surface 1 has the texture of the gears eliminated by the texture, the scaly scissors 2 will be appropriately arranged, so the other tooth surface at the edge 3 of the scissors 2 By optimally cutting one protrusion, the tooth surface 1 can be smoothed to improve the conformability of the tooth surface 1 very easily, and the strength of the tooth surface 1 can be further improved.

  According to the meshing assembly of the present embodiment, the tooth surface 1 is provided in the at least one of the tooth surfaces 1 to be meshed with a small scaly barb 2 facing in a random direction. The edge 3 of the tooth 1 cuts the projections of the other tooth surface 1 to smooth the tooth surface 1 and improve the conformability of the tooth surface 1. As a result, peeling damage is suppressed and the strength of the tooth surface 1 is improved. Can be improved.

  According to the method for improving the tooth surface strength of the present invention, fine and hard particles collide with the tooth surface 1 of the gear at high speed, so that the tooth surface 1 of the gear has a minute scaly shape in a random direction. The feed 2 can be formed easily.

  In addition, the gear, the meshing assembly, and the tooth surface strength improving method of the present invention are not limited to the above-described illustrated examples, and the tooth surface of the gear and the meshing assembly is provided with minute scaly ridges in a random direction. Of course, other manufacturing methods may be used, and various modifications can be made without departing from the scope of the present invention.

It is sectional drawing which shows notionally the fine scaly ridge formed in the tooth surface of the embodiment which implements this invention. It is a perspective view which shows notionally the fine scaly roll formed in the tooth surface of the embodiment which implements this invention. It is a photograph which shows the state before performing the process of the tooth surface strength improvement method in the tooth surface of the embodiment which implements this invention. It is a photograph which shows the state after performing the process of the tooth surface strength improvement method in the tooth surface of the embodiment which implements this invention. It is a graph which shows the tooth surface roughness before a driving | running | working in a tooth surface strength improvement method, impeller type shot peening, and unprocessed. It is a graph which shows the tooth surface roughness after a driving | operation in the process of a tooth surface strength improvement method, and impeller type shot peening.

Explanation of symbols

1 tooth surface 2 crush 3 edge

Claims (6)

  A gear having a minute scaly ridge on the tooth surface in a random direction.   2. The gear according to claim 1, wherein the scaly ridges are formed by a texture in which undulations having a pitch of about several μm to about 100 μm are randomly layered.   2. The gear according to claim 1, wherein the scaly ridges are formed by a texture in which undulations of several μm and undulations of 40 to 100 μm are overlaid.   The gear according to any one of claims 1 to 3, wherein at least the meshing surface of the tooth surface is formed by eliminating the work of the gear by the texture.   A meshing assembly configured to mesh the tooth surfaces of a pair of gears, wherein the gear assembly according to claim 1 is provided on at least one of the meshing tooth surfaces.   A method for improving the tooth surface strength, wherein fine and high hardness particles collide with a tooth surface of a gear at a high speed to form minute scaly ridges on the tooth surface in a random direction.

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