JP2008049472A - Hob and gear cutting method using the hob - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hob and a gear cutting method using the hob. <P>SOLUTION: The hob is equipped with a plurality of cutting teeth 22 and the cutting teeth are equipped with a first tooth part and a second tooth part having a different machining shape from a tooth root toward the tip end. The first tooth part forms a first temporary open line profile on a machined block, and the second tooth part forms a curved profile on the machined block. A first temporary open line route and the curved profile crossing each other at an indicated position point are set on a workpiece body, and the rotating axis direction of the hob and the rotating axis direction of the workpiece body determine an included angle and machines so that the profiles drawn by the first and second tooth parts become the first temporary open line route and the curved profile. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hob and a gear cutting method using the hob. In particular, a hob having cutting teeth with two different contour structures, and a gear cutting method using the hob for forming a gear tooth and a gear root release area of a primary open-line structure of a gear by cutting with the hob Concerning.

In the known gear cutting process, the tooth profile is cut by the cutting motion of the block to be processed and the cutter, first a semi-finished processed tooth is formed by a worm-shaped hob, and further, the gear wheel is processed by a gear having a gear wheel shape. Complete.
As shown in FIG. 1 showing a known gear outer mold, the gear 10 includes a disk-shaped main body 11 and gear teeth 12 are formed on the outer peripheral edge of the main body 11. A gear tooth groove 13 is provided between the two gear teeth 12, and the gear tooth groove 13 is mainly formed by a two-step process of drilling and gear formation.
As shown in FIG. 2, first, drilling 131 is performed at a predetermined position on the main body 11. The position and size of the drilling 131 are determined according to the actual gear specifications. After the drilling process of the main body 11 with a drill, teeth are cut according to primary open line routes L1 and L2 of gear meshing symmetrically on both sides of the center of drilling 131 with a hob (not shown). Thus, the side 121 of the gear tooth 12 is formed, and the drilling 131 by the drill achieves the gear tooth root 123 release effect.
The main purpose of the release is the following two points.
(1) When making a serration on the gear, prevent the saw cutter from colliding with the gear body in the saw tooth area.
(2) When the gear cuts the hob, it provides a space to eliminate cutting waste.

However, since the known manufacturing process is performed in two steps, drilling and gear tooth cutting, the following drawbacks exist.
1. Since the diameter d1 of the drilled hole 131 is larger than the gear tooth 12 and the gear root interval distance d2, the gear tooth 12 forms a thin neck 122, but the presence of the neck 122 reduces the strength of the gear tooth 12. It is easy to break at the position of the neck 122.
2. When the drilling of the main body 11 is completed and the main body 11 is set on the gear tooth cutting machine, the gear tooth cutting cannot be performed accurately unless the positioning is performed again.
3. Since it is necessary to install a drilling machine base and a tooth cutting machine base with a drill, the equipment cost becomes high and more space is required.
4. Since the volume of the main body 11 is large and heavy, it is extremely inconvenient to carry the drill up and down between the drilling machine base and the tooth cutting machine base. There is a risk that.
In order to solve the above problem, a gear 14 (see FIG. 3) with two different curved contours 141, 142 is designed and the gear root release effect is achieved by the release area 143 formed by the curve 142. However, since the gear shown in FIG. 3 is known in the art and mainly performs two tooth cutting operations to achieve tooth profile formation of two different curves 141 and 142, such a manufacturing process is performed in the machining process. Cost and labor consumption.
JP 2005-59163 A JP 2005-66706 A

The known structure has the following drawbacks.
That is, since the manufacturing is performed in two steps, the formed thin neck is fragile and easily torn, and tooth cutting cannot be performed accurately unless the positioning is performed again. Furthermore, since two types of equipment are required, the cost becomes high, the space is increased, and the main body is large and heavy. Therefore, the vertical transportation between the two machine tools is inconvenient, and labor and time are wasted. There is a risk of damaging your body.
The new manufacturing process that solves the above problem also wastes time in the machining process, leading to consumption of production costs and manpower.
The present invention provides a hob that solves the problems of the above structure and a gear machining method used for the hob.

In order to solve the above problems, the present invention provides the following hob and a gear machining method used for the hob.
Provided is a hob and a method of gear machining used for the hob, the hob having a structure with two different contours on a cutting tooth, and simultaneously two different curves on one work block Achieving tooth profile contouring with
Further, a hob and a gear machining method used for the hob are provided, the gear is machined by using the hob formed by the cutting teeth having two different contour structures, and the gear release area is formed at a time. Achieve the purpose of molding,
Ie it includes a hob body, multiple cutting teeth,
The hob body includes a plurality of cutting waste discharge grooves,
The plurality of cutting teeth are formed on the hob body, and are positioned on both sides of the cutting waste discharging groove, and the cutting teeth further include a first tooth portion and a second tooth portion,
The first tooth portion may be formed on the hob body, and the first tooth portion may form a first primary open line contour of a gear on one work block, and the second tooth portion Can form a gear release curve contour on the work block,
The second tooth is optimally formed on the first tooth,
The curved contour is optimally a contour formed by excessive cutting of the second tooth portion,
The curve contour is optimally a primary open line contour,
Optimally, the work block is a gear and the area formed by the curved contour is the release area of the gear;
Furthermore it provides a hobbing method, which comprises the following steps:
The first tooth portion may be formed on the hob body, the first tooth portion may form a first primary open line contour on one work block, and the second tooth portion may be the covered portion. A curved contour can be formed on the machining block,
The second tooth is optimally formed on the first tooth,
The curved contour is optimally a contour formed by excessive cutting of the second tooth portion,
The curve contour is optimally a primary open line contour,
Optimally, the work block is a gear and the area formed by the curved contour is the release area of the gear;
In addition, it further provides a method of forming a gear, which includes the following steps:
Providing a workpiece body, setting a route for a first primary open line contour and a route for a release area contour intersecting each other at specified position points on the workpiece body;
Providing a hob, comprising a plurality of cutting teeth, the cutting teeth further comprising a first tooth portion and a second tooth portion, the hob performing a rotational cutting on the workpiece body according to a cutting route; Forming a profile with a first primary open line by the first tooth and forming a gear of the release area profile by the second tooth;
The determination method of the route of the first primary open line contour and the route of the release area contour may further include the following steps:
First determining a route of the first primary open line contour, setting the designated position point on the route of the first primary open line contour, and forming a tooth thickness of the designated position point; It is optimal to set the specified position point pressure angle, and further draw the line by finding the release area contour by the diameter, pressure angle, tooth thickness, spiral angle of the specified position point,
The release area contour is optimally a contour formed by excessive cutting of the second tooth,
The hob and gearing method used for the hob, characterized in that the release area profile is optimally a primary open line profile.

As in the structure of the present invention and each of the embodiments described above, the present invention includes a hob with a special tooth profile, and can produce a gear with two different curved contours by a single rotary cutting, It is highly practical in effect and has extremely high utility in the industry.

As shown in FIG. 4, which is a perspective view of the hob of the present invention, the hob 2 includes a hob body 20 and a plurality of cutting teeth 22.
The hob body 20 includes a plurality of cutting waste discharge grooves 21.
The plurality of cutting teeth 22 are formed on the hob body 20 and are located on both sides of the cutting waste discharge groove 21.
As shown in FIG. 5, which is a cutting tooth profile contour instruction diagram of the hob of the present invention, the cutting tooth 22 further includes a first tooth portion 220 and a second tooth portion 221.
The first tooth portion 220 can be formed on the hob body 20, and the first tooth portion 220 can form a first primary open line contour on one work block. The second tooth portion 221 is formed above the first tooth portion 220 and forms a curved contour on the block to be processed.
The curved contour is a primary open line contour or a contour formed by further deeply cutting the work block by the second tooth portion 221. The cutting waste discharge groove forms a direction intersecting the axis of the hob body, and the hob can be a straight cutting waste discharge groove or a cutting waste discharge groove having a spiral angle according to the intersecting direction. .

Utilizing the hob 2, the present invention further provides a method of gear production. As shown in FIG. 6, which is a process instruction diagram of an optimal embodiment of the gear formation method of the present invention, the method 3 includes the following steps.
First, in step 30, a workpiece body is prepared (provided).
Next, the tooth profile of the gear is determined in step 31, and the route of the first primary open line and the route of the release area contour intersecting each other at a specified position point on the workpiece body are set. The release area contour can be selected as a primary open line contour or a deeper cutting contour.
As shown in FIG. 7 which is a processing route contour instruction diagram on the workpiece main body, a first primary open line L5 and a curved contour L6 are set for the workpiece main body 4. The curved contour L6 is a contour formed by deeper cutting during hobbing in the present embodiment. The primary open line L5 and the curved contour L6 intersect each other at the designated position point P. The position of the first primary open line L5 represents the area where the gear teeth of the gear and the block to be processed mesh when the gear is formed in the future, and the curved outline L6 represents the release area outline.

The determination method of the first primary open line L5 and the curved contour L6 is as follows. As shown in FIG. 7, first, the first cutting route of the first primary open line L5 route is set, and then the designated position point P is set on the first primary open line L5. The determination method of the first primary open line is to determine a base circle on the workpiece body 4 according to the tooth profile of the gear, and subsequently to set the first primary open line L5 based on the base circle. Arise. Since the primary open line method for generating the base circle is a known technique, it will not be described in detail here.
In addition, the principle of determining the designated position point P is determined based on the necessity of the gear release area. In general, the designated position point P is usually located below a primary open line starting point (SAP). The SAP location is determined based on the needs of the standard. This is known to those skilled in the term, and is not described in detail, but is based on the following equation.
T = 2r ((T1 / 2R1) + invψ1-invψ)
T = tooth thickness at specified point
r = specified point radius
T1 = tooth thickness at the pitch circle position
R1 = Pitch circle radius
invψ1 = pitch circle vector angle;
invψ = specified point vector angle;
In this way, the tooth thickness T of P at the designated position point can be obtained. Next, the pressure angle ψ of the specified position point P is set, the diameter OD _i and the spiral angle HA _i of the specified position point P are further set, and the absolute value Mn _i of the second tooth portion 221 is determined based on the following equation: To do.
Mn _i = OD _i Cos (HA _i ) / Z
Z = gearwheel teeth in this way, it is possible to draw a curve contour L6 determined pressure angle [psi, the tooth thickness T and the absolute value Mn _i.

As shown in FIG. 6 again, in step 32, the hob shown in FIG. 4 is used to perform processing based on the arrangement shown in FIG.
In FIG. 8, the central axis 23 of the hob 2 and the central axis 40 of the workpiece body 4 are in an intersecting relationship, and if the intersecting angle (that is, the two axes 23, 40 are projected onto a plane). When the angle between the two shafts 23 and 40 is 90 degrees, the machined gear has no spiral angle. Conversely, if it is not 90 degrees, the gear has a helical angle.
Further, as shown in FIG. 5 again, the first tooth portion 220 and the second tooth portion 221 on the cutting tooth 22 of the hob have tooth profile contours corresponding to the primary open line L5 and the curved contour L6. is there. Subsequently, in step 33, the hob performs rotary cutting on the workpiece body according to a cutting route, and the first and second tooth portions are the first intersecting first open line outlines. And a gear with a curved contour. Here, the cutting route is a play line route. The first primary open-line outline is a contour processed by the first tooth portion, and the curved contour is a contour formed in the workpiece body cut by the second tooth portion deeper. In addition, the curved contour is also a primary open-line contour, and the design method is determined by the tooth thickness and absolute value equations.

As shown in FIG. 9 which is a cutting route diagram when the hob of the present invention processes the workpiece body, the rack formed by the cutting teeth 22 of the hob is shown in FIG. Only). Further, as shown in FIG. 8, when the hob 2 rotates, the cutting teeth on the hob 2 form the cutting route shown in FIG. In the process of rotational cutting of the hob, the cutting route shown in FIG. 9 of the rack formed by the cutting teeth is once the gear tooth profile contour formed by the first primary open line L5 and the curved contour L6 in FIG. The cutting process is used.
Further, the cutting route is the play line route, and the contour of the play line L7 is formed at the end of the curved contour. Finally, the gear shown in FIG. 10 is formed by the above processing operation.

It is a gear instruction | indication figure of a well-known technique. FIG. 3 is a view showing a gear tooth profile and a root release area according to the prior art. FIG. 2 is an illustration of a known structure with different curvilinear gear teeth and root release areas. It is a hob solid instruction | indication figure of this invention. It is a cutting tooth profile outline directions figure of the hob of the present invention. It is a process instruction | indication figure of the Example of the optimal gear formation method of this invention. It is a process route outline directions figure on the work body. It is a relative position instruction | indication figure of the hob of this invention, and a workpiece main body. FIG. 4 is a route diagram when performing hobbing on the workpiece body in the present invention. FIG. 4 is an instruction diagram for forming a gear by performing hobbing on the workpiece body in the present invention.

Explanation of symbols

10 Gear
11 Disc type body
12 gear teeth
121 side
122 Neck
123 Gear tooth root
13 Gear tooth gap
131 Drilling holes
14 Gear
141 Primary open line contour
142 Curve contour
143 release area
d1 diameter
d2 Gear tooth root distance
L1, L2 Primary open line route
2 Hob
20 Hob body
21 Cutting waste discharge groove
22 Cutting teeth
220 First tooth
221 Second tooth
23 Center axis
3 Gear formation method
30-33 process
4 Workpiece body
40 central axis
L5 1st primary open wire
L6 Curve contour
L7 Play Line
P Specified position point

Claims (7)

In a hob in which a plurality of cutting teeth are formed on the hob body,
The plurality of cutting teeth are arranged with a plurality of cutting waste discharge grooves therebetween,
And it consists of a first tooth part and a second tooth part formed above it,
The first tooth is formed on the hob body to form a first primary open line profile of the gear in the machining block;
The hob characterized in that the second tooth portion forms a release curve contour of a gear on the processed block. The hob according to claim 1, wherein the second tooth portion is formed above the first tooth portion. The hob according to claim 1, wherein the release curve contour is a portion of a contour formed by cutting the second tooth portion deeper for gear release or a primary open line contour. 2. The hob and a gear machining method used for the hob according to claim 1, wherein the block to be machined is a gear, and an area formed by the curved contour is a release area of the gear. In the gear cutting method,
Set the first primary open line contour route and the release area contour route intersecting each other at the specified position point on the workpiece body,
Provided with a plurality of cutting teeth, the cutting teeth further prepare a hob having a first tooth portion and a second tooth portion,
The hob performs rotary cutting on the workpiece body according to the cutting route, the first tooth portion forms a contour with a first primary open line of the gear, and the second tooth portion. A gear cutting method using a hob, characterized in that a gear having the release area contour is formed by the following. In routing the first primary open line contour and the release area contour,
First determine the route of the first primary open line contour,
Setting the designated position point on the route of the first primary open line contour;
6. The tooth thickness of the designated position point and the pressure angle of the designated position point are set, and the route of the release area contour is obtained from the diameter, pressure angle, tooth thickness, and helical angle at the designated position point. A gear cutting method using the described hob. The gear cutting method according to claim 6, wherein the release area contour is either a contour formed by excessive cutting of the second tooth portion or a primary open line contour.

Images