JPH0332437A - Manufacture of gear having growing - Google Patents

Abstract

PURPOSE:To manufacture the gear of high accuracy by forming a tooth having a crowning in the periphery of a columnar gear body with a bulge part by a pair of form rolling dies for the gear having a crowning provided with a die tooth having die whole depth extending over the overall length in the tooth thickness orthogonal direction. CONSTITUTION:The periphery of a middle position in the longitudinal direction of a columnar gear body 4 of an object B to be worked becomes a bulge part 4a being larger than both end parts in this longitudinal direction. Subsequently, a pair of form rolling dies A for a gear having a recessed circular arc-like die tooth root part 2a in the tooth thickness orthogonal direction, a recessed circular arc-like die tooth top part 2b in the tooth thickness orthogonal direction, and a die tooth surface part (2c) having an inverted crowning, and having a crowing provided with a die tooth 2 having die whole depth extending over the overall length in the tooth thickness orthogonal direction are provided. By using this die A, plural teeth having a crowning are formed in the periphery of the columnar gear body with the bulge part. In such a way, the tooth having a crowning can be manufactured with high accuracy and simply.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a gear with crowning, which makes it possible to manufacture teeth with crowning with extremely high precision.

[Conventional technology]

Traditionally, teeth with crowning have existed, but
When this is enlarged, as shown in Fig. 23, both ends of the tooth in the direction perpendicular to the tooth thickness bulge out slightly, and as a result, the center position of the maximum crowning i1wo is slightly depressed when viewed from the side. It became. This is due to the configuration of the conventional rolling die A for gears made of carbide tool material or the like. That is, as shown in FIGS. 1O to 13, in a plurality of die teeth 2 provided on the upper surface of the die body 1 of the rolling die A, the die root portion 2a of the die tooth 2 is aligned in the direction perpendicular to the tooth thickness. The die tooth tip portion 2b also has a concave arc shape in the direction perpendicular to the tooth thickness, and the tooth trace 2c+ of the die tooth surface portion 2c has a reverse crowning (in this specification, the concept is opposite to "crowning"). ).
Further, the total die tooth height of the die teeth 2 is formed to be the same everywhere. Further, an arcuate corner portion 2d having a small radius is formed over the entire length in the direction orthogonal to the tooth thickness at the corner portion between the die tooth tip portion 2b and the die tooth surface portion 2c.
When viewed from a plane orthogonal to the die tooth tip 2b, the die tooth tip 2b has a constricted central portion. In addition, the die teeth 2 of the rolling die A are formed so that the initial biting part is low and the height gradually increases, and in the state shown in FIG. 3, the full tooth height of the die is formed. There is. In addition, since the die teeth 2 are formed of a disc grindstone a, they have a concave arc shape in the direction perpendicular to the tooth thickness.
The approximate center line in the direction perpendicular to the tooth thickness for the full tooth height of this die is:
It has a concave arc shape in the direction perpendicular to the tooth thickness, and is referred to as a die tooth pinch line p in this specification (see FIG. 12).The actual die pitch circle is a straight line.

When a pair of such rolling die tooth bases are rolled (see Fig. 20), the concave arc-shaped die tooth tip 2 is formed.
At b, the gear material is extremely pressed, and as a result, the pressed member slightly bulges upward, and the center position has a crowning amount W, as shown in FIGS. 21 and 22. , there is almost no bulge. This amount of bulge became more noticeable as the amount of crowning W6 increased.

Further, as shown in FIG. 19, the rolling die A was formed by processing a cemented carbide tool material or the like using a grinding machine using a disc grindstone a. Specifically, by grinding a disc grindstone a of an appropriate diameter whose circumferential cross section is cut into a bottomed 7-shape (see Fig. 19), or by grinding a small diameter disc grindstone a in an arc shape. By grinding while grinding, a rolling die A for gears used for teeth with crowning was manufactured. Teeth with crowning can be obtained by processing with the rolling die A because the root of the gear in the direction perpendicular to the tooth thickness is concave when viewed from the tooth thickness direction, as shown in FIGS. 20 and 21. Although it is formed in an arc shape, the tooth tip of the product is formed with a small pressing force at the die root portion 2a, and the tooth tip is formed in a substantially horizontal direction in the direction perpendicular to the tooth thickness.
With these tools, a gear with a crowning as shown in FIG. 23 was machined.

[Problem to be solved by the invention]

Therefore, a gear having a crowning that has been rolled in this manner has a problem in that the accuracy of the tooth profile, such as when measuring the tooth thickness of the teeth, is reduced. In addition, if you try to increase the amount of crowning, both ends of the tooth tip will bulge out and the center will become depressed), and both ends in the tooth width direction will sag. There are inconveniences such as the need to provide extra thickness at the tip and then perform polishing to obtain the required tooth height.

C? Measures to resolve IN] Therefore, the inventor mentioned above! Working hard to solve IB.

As a result of repeated research, the invention was developed by making the circumference of the cylindrical gear body of the workpiece at an intermediate position in the longitudinal direction a bulge having a larger diameter than both ends of the longitudinal direction, and then It has a die root part having a concave arc shape in the direction perpendicular to the tooth thickness, a die tooth tip part having a concave arc shape in the direction perpendicular to the tooth thickness, and a die tooth surface part having reverse crowning, and has a die root part having a concave arc shape in the direction perpendicular to the tooth thickness. Crowning is performed by forming a plurality of teeth having crowning on the circumferential surface of the cylindrical gear body with the bulging member using a pair of rolling dies for gears having crowning and having die teeth having the full die tooth height. By adopting a manufacturing method for gears with crowning, teeth with crowning can be manufactured with extremely high precision.
This solves the above problem.

(Example) Hereinafter, the manufacturing method of the present invention will be explained based on the drawings.

First, the structure of workpiece B used in the manufacturing method will be described.

B is a workpiece, and in the embodiment, a cylindrical gear body 4 is integrally formed at the end of the shaft portion 3.

Although not shown, the cylindrical gear body 4 alone may serve as the workpiece B, and is not limited to the embodiment.

Reference numeral 4a denotes a bulge, which is formed so that the circumference of the cylindrical gear body 4 at the center in the longitudinal direction has a larger diameter than both end portions in the longitudinal direction. There are multiple embodiments of the bulging portion 4a, and in the first embodiment, as shown in FIG. A bulge is formed.

In addition, as shown in FIG. 8, the second embodiment of the bulging portion 4a has a trapezoidal mountain shape in cross section so that the circumference at the center position in the longitudinal direction of the cylindrical gear body 4 is maximum. It is formed to disappear at both ends or in the middle in the longitudinal direction.

Furthermore, as shown in FIG. 9, in the third embodiment of the bulging portion 4a, the cylindrical gear body 4 has the maximum circumference at the center position in the longitudinal direction, and has a chevron-shaped arc shape in cross section. It is formed so that it disappears at both ends or in the middle of the direction. In this case, the shape is such that the diameter φ2 at the center position is larger than the diameter φ at the end portions.

Next, the manufacturing method will be explained. First, as shown in FIG. 1, the workpiece B is rotatably mounted on a gear rolling machine.Next, the pair of rolling dies A, with the die teeth 2.2 of A facing each other, As shown in Figure 2,
The die teeth 2 are moved from side to side with respect to each other.
The die tooth tip 2b bites into the bulge 4a of the workpiece B (see FIGS. 2 and 4), and when it is further moved (see FIG. 5), the die tooth tip 2b At this time, the outer circumference of the cylindrical gear body 4 is also pressed and rolled while pressing the bulging portion 4a, and furthermore, this rolling tooth becomes deeper (see Fig. 6), and in the final stage of movement ( (see Fig. 3), and gears as shown in Fig. 7 are rolled.

Specifically, the teeth 5 of the gear include a root portion 5a and a tooth tip portion 5b.
and a tooth surface portion 5C. The tooth trace 5c of the tooth 5 has a crowning direction.

As shown in FIG. 16, crowning refers to the creation of an appropriate bulge in the tooth trace 5c+ direction of the tooth surface portion 5c of the tooth 5, and is intended to improve tooth contact. Further, crowning fitWI or W2 represents the amount of bulge, and in FIGS. 17 and 18, the crowning fitWI or W2 refers to the bulge from the end to the maximum bulge position in the middle. This crowning is symmetrically formed in a spindle shape in a direction perpendicular to the tooth thickness.

Further, the longitudinal direction of the tooth tip portion 5b is shaped to be parallel to the axis S of the main body (see FIG. 15).

〔Effect of the invention〕

In the present invention, the intermediate position circumference in the longitudinal direction of the cylindrical gear main body 4 of the workpiece B is made into a bulged portion 4a having a larger diameter than the both end portions in the longitudinal direction, and then the tooth thickness is orthogonally It has a die root part 2a having a concave arc shape in the direction, a die tooth tip part 2b having a concave arc shape in the direction perpendicular to the tooth thickness, and a die tooth surface part 2c having reverse crowning, and has a die tooth root part 2a having a concave arc shape in the direction perpendicular to the tooth thickness. Using a pair of rolling dies A for gears having crowning and having die teeth 2 having the full die tooth height, crowning is applied to the circumferential surface of the cylindrical gear body 4 with the bulged portion 4a. By adopting a method for manufacturing a gear with a crowning in which a plurality of teeth 5 are formed, firstly, the gear with the crowning can be manufactured with high precision, and secondly, the gear can be manufactured extremely easily. crowning it on 3
This has the effect of increasing we.

To explain these effects in detail, conventionally, as shown in FIGS. 10 to 13, the die dedendum part 2a has a concave arc shape in the direction perpendicular to the tooth thickness, and the die root part 2a has a concave arc shape in the direction perpendicular to the tooth thickness. When rolling is performed using a pair of rolling dies A, which consists of a die tooth tip portion 2b and a die tooth flank portion 2C whose tooth trace has reverse crowning, the concave arc shape is formed as shown in Fig. 20. The tip of the die teeth 2b presses the workpiece extremely, and as a result, as shown in FIGS. 21 and 22, the pressed member slightly bulges upward, and Since the center position has a crowning amount w (see Fig. 23), it hardly bulges out, and as a result, teeth with crowning are formed as shown in Fig. 23, although it is a little extreme, and the gear However, according to the manufacturing method of the present invention, even if the rolling die A is the same, the longitudinal direction of the cylindrical gear body 4 of the workpiece B is Since the circumference of the intermediate position has a bulge portion 4a having a larger diameter than the end portions in the longitudinal direction, the die is shaped like a concave arc, as shown in FIGS. 4 to 7. Even if the outer circumferential portion of the cylindrical gear body 4 of the workpiece B is pressed with the tooth tip portion 2b, the material gradually flows around the bulged portion 4a, and eventually the material flows as shown in FIG. Thus, the tip portion 5b of the tooth 5 can be processed into a substantially flat shape. The process shown in FIGS. 4 to 7 is extremely uneven in the drawings, but this action is clarified.

Therefore, unlike the conventional method shown in FIG. 23, both ends of the tooth tips do not bulge, and according to the manufacturing method of the present invention, even if the same rolling die A as the conventional method is used, There is an advantage that the tips 5b of the teeth 5 of the gear can be processed into a substantially flat shape by a simple manufacturing method in which the cylindrical gear main body 4 of the workpiece B is processed after forming the bulge 4a.

By being able to process it in this way, it has the effect of significantly improving the accuracy in measuring the tooth thickness of the matagi, which is used as a guide for determining the accuracy of gears.

In addition, in the conventional method, when trying to increase the crowning amount W6 (see Fig. 23), both ends of the tooth tip bulge out and the center becomes concave), and both ends in the tooth width direction sag.
There was an inconvenience in that extra thickness had to be provided at the tip of the tooth so that it was larger than the required tooth height, and then polishing was performed to achieve the required tooth height, but the manufacturing method of the present invention Now, as mentioned above, since the bottom shape of the tooth 5 can be made with an extremely regular crowning without a dent in the center of the tooth tip 5b, there is no need for corrective polishing of the tooth tip 5b.
This has the advantage of improving manufacturing efficiency and reducing manufacturing costs.

Furthermore, in the manufacturing method of the present invention, even if the concave arc-shaped die tooth tip 2b is pressed, the first
As shown in Fig. 7 and Fig. 18, crowning 1w,,w
It is possible to increase z slightly and manufacture highly accurate teeth 5.

Moreover, the manufacturing method of the present invention changes the shape of the workpiece B,
Thereafter, there is no difference from conventional rolling processing, so there is a great advantage that gears with crowning can be manufactured with high precision simply as in the conventional method.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, in which Figure 1 is a schematic perspective view of the manufacturing method of the present invention before processing, and Figure 2 is a schematic side view of the manufacturing method of the present invention during processing. , FIG. 3 is a schematic side view of the completed process according to the manufacturing method of the present invention, and FIG. 4 is a diagram showing FIG. 2 IV.
-IV arrow sectional view, FIG. Figure 6 is a cross-sectional view of the main part at a further rear stage than the case in Figure 4, Figure 7 is a cross-sectional view taken from the ■-■ arrow in Figure 3, and Figures 8 and 9 are different implementations of the workpiece. A partial side view of an example, FIG. 10 is a perspective view of a conventional rolling die for floats used in the manufacturing method of the present invention, FIG. 11 is a plan perspective view of FIG.
FIG. 13 is an enlarged sectional view taken along the line P-P in FIG. 16 is an enlarged perspective view of a tooth with a crowning manufactured by the manufacturing method of the present invention; FIG. 17 is a partially sectional side view of the figure;
FIG. 18 is an enlarged plan view of a tooth with a crowning manufactured by the manufacturing method of the present invention, FIG. 19 is a sectional view of a conventional rolling die in a manufacturing state, and FIG. 20 is a conventional rolling of a gear with a crowning. A cross-sectional view of the machining state, Figure 21 is the second
FIG. 22 is an enlarged sectional view of the main part in FIG. 21 taken along the Q-Q arrow, and FIG. FIG. A...Rolling die, 2...Die tooth, 2a...Die tooth base, 2b...
・Die tooth tip, 2C...Die tooth surface, B
...Workpiece, 4...Cylindrical gear body, 4a...Bulging part, Dsax...Maximum depth position,
h...Full die tooth height, 5...teeth.

Claims (1)

[Claims] (1) The circumference at an intermediate position in the longitudinal direction of the cylindrical gear body of the workpiece is made into a bulge having a larger diameter compared to both ends of the longitudinal direction, and then a concave circle is formed in the direction perpendicular to the tooth thickness. It has an arc-shaped die tooth base, a concave arc-shaped die tooth tip in the direction perpendicular to the tooth thickness, and a die tooth surface having reverse crowning, and has the full die tooth height over the entire length in the direction perpendicular to the tooth thickness. A gear with a crowning, characterized in that a plurality of teeth with a crowning are formed on the circumferential surface of the cylindrical gear body with a bulging member using a pair of rolling dies for a gear with a crowning with die teeth. manufacturing method.