JPS61178113A - Gear grinding method using gear-shaped wheel - Google Patents

Abstract

PURPOSE:To improve machining accuracy, by engaging a gear to be ground with a gear-shaped wheel so that an intermeshing pitch circle is positioned in the vicinity of the end part of a necessary addendum in the gear-shaped wheel and obtaining a uniform grinding speed. CONSTITUTION:A gear-shaped wheel 2 is designed so that an intermeshing pitch circle 8 is positioned in the bottom land side of the gear-shaped wheel 2 from its necessary addendum 7. Each part, actually relating to grinding, in the necessary addendum 7 of the gear-shaped wheel 2 is continually brought into slide contact almost in an equal direction with a tooth surface of a gear to be ground, and the gear to be ground both eliminates in its tooth surface a point providing a zero grinding speed and obtains over the whole region of the tooth surface a uniform grinding speed, accordingly machining accuracy is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application> The present invention relates to an improvement in a gear grinding method using a gear-shaped grindstone.

<Conventional technology> Conventionally, as a finishing method for high-hardness gears after quenching, a generating grinding method using a gear grinder using grinding wheels of various shapes such as disc, conical, or screw shapes has been mainly used. I came. However, gear grinding using this generation method has the disadvantage that it takes a long time to grind each gear to be machined, and it is not possible to process gears with steps (shoulders). was requested.

In order to meet this demand, a gear grinding method has been proposed in recent years in which a gear-shaped grindstone is used and rotated while meshing with the gear to be cut, thereby grinding the tooth surface of the gear to be cut. This is because the tooth surface of the workpiece gear is ground using the slippage in the tooth height direction and the tooth trace direction that occurs in the contact area between the meshing tooth surfaces of the gear-shaped grindstone and the workpiece gear, so the relative speed of the contact area is the grinding speed. This meshing gear grinding method has the advantage of high machining efficiency and the ability to grind gears with steps (shoulders) that cannot be ground using the generation method.

Figures 8 and 9 are explanatory diagrams of the grinding method using this gear-shaped grindstone. In the figures, 1 is the gear to be cut, 2 is the gear-shaped grindstone, 3 is the shaft of the gear to be cut, and 4 is the gear-shaped grindstone shaft. Usually, as shown in Fig. 8, an intersection angle is given to the gear shaft 3 to be cut and the gear-shaped grindstone shaft 4, and the gear to be cut 1 and the gear-shaped grindstone 2 are meshed, and the gears are rotated by meshing rotation of the other gear. The gear-shaped grindstone 2 is designed in accordance with the specifications of the gear to be cut 1 so as to cause axial slippage on its surface. However, when there are spatial constraints such as gears with steps (shoulders), the intersection angle is 0 as shown in Figure 9.
In some cases, Further, FIG. 10 is a schematic diagram showing a cross section of one tooth of the gear-shaped grindstone 2, and each tooth 5 of the gear-shaped grindstone 2
An appropriate number of abrasive grains are present on the tooth surface 6 of the gear 1, and the abrasive grains within the required tooth height portion 7 grind the tooth surface of the gear 1 to be cut. Now, zero the abrasive grains in the required tooth height area 7 in order from the tooth tip side.
When numbered 1 to G5, the abrasive grain G1 closest to the tooth tip grinds the bottom of the gear 1 to be cut, and the abrasive grain G5 closest to the bottom grinds the tip of the gear 1. It turns out.

On the other hand, FIG. 11 is a schematic diagram showing the meshing state of the gear to be cut 1 and the conventional gear-shaped grindstone 2 in a cross section perpendicular to the grindstone axis, and the meshing circle 8 is located approximately at the center of the tooth height. Further, in the figure, 9 indicates a backlash, and when the opposite tooth flank is ground by changing the meshing rotation direction, the backlash 9 occurs on the opposite tooth flank. In this conventional meshing state, the tooth surface of the gear to be cut 1 is ground by the abrasive grains in the required tooth height portion 7 of the gear-shaped grindstone 2 as shown in FIGS. 12 and 13. Figure 12 shows the gear to be cut 1 and the gear-shaped grindstone 2.
When the axes 3 and 4 are meshed and rotated by giving a crossing angle DA, that is, when the crossing angle is 1 (the state shown in Fig. 8), the 13th
The figures show the case where the intersection angle is 6 = o (the state shown in Figure 9), and the arrows on the tooth surface in the figure are the grinding trajectories of each abrasive grain, and the direction and length of the arrow are in the grinding direction. and represents the grinding length. Further, the length of the arrow is also approximately proportional to the grinding speed. Note that the arrows labeled A1 to A5 indicate the abrasive grains G1 within the required tooth height portion 7 shown in FIG.
- Compatible with G5.

<Problems to be solved by the invention> However, in the conventional meshing gear grinding method, the first
As shown in Fig. 2 and Fig. 13, there is a large difference in the grinding speed in the tooth height direction of the tooth surface of the gear to be cut, and the direction is opposite between the tooth tip and the tooth bottom. The grinding speed becomes minimum at this point, and in some cases, the speed at that part becomes zero as shown in FIG. Therefore, not only is that portion not sufficiently ground, but also the wear and tear of the grindstone is severe when the grinding speed is low, resulting in a problem that the life of the gear-shaped grindstone 2 is short. Furthermore, 1. The first diagram schematically represents the state of change in grinding force according to the conventional gear grinding method.
As shown in FIG. 4, the grinding force Ft in the tangential direction changes as the engagement position changes in the tooth height direction, that is, as engagement progresses, and its direction is reversed between the initial and final stages of engagement. Therefore, this causes periodic force fluctuations, and changes occur in the grinding mechanism of the abrasive grains depending on the position in the tooth height direction, which may worsen the meshing rotation accuracy and the grinding mechanism depending on the position of the abrasive grains. There is a problem in that due to changes in the grinding wheel, the wear pattern of the grindstone becomes non-uniform, which adversely affects machining accuracy. In the figure, Fn is the grinding force in the normal direction, 10
indicates the line of action.

<Means for solving the problems> The present invention solves the above-mentioned problems in the conventional meshing gear grinding method using a gear-shaped grindstone.
To provide a gear grinding method that eliminates the point where the grinding speed becomes zero on the tooth surface of a gear to be machined and provides a relatively uniform grinding speed over the entire tooth surface, thereby extending the life of a gear-shaped grindstone. The purpose is to improve machining accuracy.

To achieve this object, the gear grinding method using a gear-shaped grindstone according to the present invention has a configuration in which a gear to be cut and a gear-shaped grindstone are meshed and rotated to grind the tooth surface of the gear to be cut. In the grinding method, the meshing circle is positioned near the end of the required tooth height portion of the gear-shaped grindstone that actually participates in grinding the tooth surface of the gear to be cut, or at a position within the required tooth height portion 7. It is characterized in that the gear to be cut and the gear-shaped grindstone are engaged with each other.

<Function> Each part of the necessary tooth height of the gear-shaped grindstone that actually participates in grinding always makes sliding contact with the tooth surface of the target gear in approximately the same direction, and the grinding speed becomes zero on the tooth surface of the target gear. There are no spots and a relatively uniform grinding speed is achieved over the entire tooth surface.

<Example> Embodiments of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the meshing state of the gear to be cut l and the gear-shaped grindstone 2 according to the embodiment K of the present invention in a cross section perpendicular to the grindstone axis. The gear-shaped grindstone 2 is designed to be located closer to the tooth bottom side of the gear-shaped grindstone 2 than the required tooth height portion 7 of the gear-shaped grindstone 2. When the gear 1 to be cut and the gear-shaped grindstone 2 are meshed and rotated, the tooth surfaces of the gear 1 to be cut are ground as shown in FIGS. 2 and 3.

Figure 2 shows that when the crossing angle is ONO as shown in Figure 8, the third
The figures each show the case where the intersection angle Da=0 as shown in FIG.

As shown in FIGS. 2 and 3, a relatively uniform grinding speed can be obtained over the entire tooth surface of the gear to be cut 1, that is, a grinding speed that is oriented in approximately the same direction and has approximately the same size. . Also,
Not only in the case of a crossing angle of 11, but also in the case of a crossing angle of 00, which conventionally had a point of zero grinding speed, there is no point where the grinding speed becomes zero as shown in FIG.

Further, FIG. 4 is a schematic diagram showing the meshing state of the gear-shaped grindstone 2 and the gear to be cut 1 according to another embodiment of the present invention in a cross section perpendicular to the grindstone axis. In the embodiment shown in FIG. 4, the gear-shaped grindstone 2 is designed such that the meshing circle 8 is located closer to the tip of the gear-shaped grindstone 2 than the required tooth height portion 7 of the gear-shaped grindstone 2. In this case, the tooth surface of the gear to be ground 1 is ground as shown in FIG. 5 when the intersection angle is ONO, and as shown in FIG. 6 when the intersection angle G=0.

That is, in this embodiment, as in the above-mentioned embodiments, a relatively uniform grinding speed can be obtained over the entire tooth surface of the gear to be cut 1, and the grinding speed can be maintained even when 1 intersection angle is 0. A point that becomes zero does not occur.

Furthermore, FIG. 7 is a schematic diagram showing an example of the state of change in the grinding force according to the method of the present invention. The directions thereof are substantially the same, and as shown in FIG. 7, the direction of the tangential grinding force Ft does not change even if the engagement position in the tooth height direction changes. Therefore, the grinding force FtO
Compared to the conventional method in which the direction is reversed, fluctuations in the grinding force can be suppressed to a small level, and the single abrasive grinding mechanism does not change much in the tooth height direction, making it possible to obtain a uniform wear pattern of the grindstone.

<Effects of the Invention> As described above in detail with reference to examples, according to the method of the present invention, there is no point where the grinding speed becomes zero on the tooth surface of the workpiece gear, and the grinding speed is relatively reduced over the entire tooth surface. Since a uniform grinding speed can be obtained, it is possible to extend the life of the gear-shaped grindstone and improve machining accuracy.

[Brief explanation of drawings]

FIG. 1 and FIG. 4 are schematic diagrams showing the meshing state of the gear-shaped grindstone and the gear to be cut according to the embodiment K of the present invention, respectively;
FIG. 2, FIG. 3, FIG. 5, and FIG. 6 are explanatory diagrams of examples of the grinding state of gear tooth surfaces ground by the method of the present invention, respectively;
Fig. 7 is a schematic diagram showing an example of changes in grinding force according to the method of the present invention, Figs. 8 and 9v are explanatory diagrams of the grinding method using a gear-shaped grindstone, respectively, and Fig. 10 is a cross-section of one tooth of the gear-shaped grindstone. FIG. 11 is a schematic diagram showing the meshing state of a conventional gear-shaped grindstone and a gear to be cut, and FIGS. 12 and 13 are
Each figure is an explanatory diagram of an example of the state of grinding of a gear tooth surface ground by a conventional method, and FIG. 14 is a schematic diagram showing an example of a state of change in grinding force by the conventional method. In the drawings, 1 is a gear to be cut, 2 is a gear-shaped grindstone, 7 is a required tooth height, and 8 is a meshing circle.

Claims (1)

[Claims] In a gear grinding method in which a gear to be cut and a gear-shaped grindstone are meshed and rotated to grind the tooth surface of the gear to be cut, the gear-shaped grindstone is required to actually participate in grinding the tooth surface of the gear to be cut. A gear grinding method using a gear-shaped grindstone, characterized in that the gear to be cut and the gear-shaped grindstone are engaged so that the meshing circle is located near the end of the tooth height portion or at a position other than the required tooth length portion. .