RU50140U1 - SINGLE WRITCH MILL FOR CHIMNEY REMOVAL - Google Patents

Abstract

The utility model relates to metalworking and can be used for chamfering at the ends of the teeth of spur gears. The problem to be solved: reducing the nomenclature of cutting tools and increasing the productivity of machining chamfers at the ends of spur cylindrical wheels. The single-turn worm milling cutter for chamfering contains teeth 1, separated by chip grooves 2. Each tooth has two main cutting edges 3 and 4 on the sides of the tooth, and an auxiliary cutting edge 5 on the top of the tooth. The main cutting edges 3 and 4 have different profile angles α _{0 rights.} and α ₀ left for the right and left sides of the cutter tooth, in addition, the thickness of the teeth 1 is a variable that increases from the first tooth to the last, and the thickness of the first cutter tooth is equal to the circumferential width of the cavity of the machined wheel, and the difference in tooth thickness depends on the linear size chamfers and the number of teeth of the cutter, while the value of the axial step, measured between the center lines of the teeth, is equal to the circumferential step of the machined wheel along the arc of the pitch circle.

Description

The utility model relates to metalworking and can be used for chamfering at the ends of the teeth of spur gears.

Known worm single-turn mill for chamfering at the ends of the teeth of helical and bevel gears, selected as the closest analogue, containing teeth separated by chip grooves, made on one turn of the worm and having a main cutting edge on one side with a profile angle α ₀ and an auxiliary the cutting edge at the top of the tooth, while the axial step P _{0 of the} cutter differs from the circumferential step of the machined wheel and is determined by the dependence

P ₀ = P _t ± K _NAP ### U402

where: P ₀ - axial step of the cutter;

P _t is the pitch of the machined wheel along the pitch circle;

### U402 - linear chamfer size;

K _{NAP - the} coefficient of direction of the helical line of the teeth of the machined wheel (K _NAP = 1 - the right direction, K _NAP = -1 - the left direction),

and the angle of the profile is determined by the dependence:

where: h is the height of the machined section of the tooth of the wheel;

h _{0 is the} height of the working section of the cutter;

α _{1 is the} end angle of the wheel profile;

γ _beginning and γ _{con are the} angles between the front surface of the cutter tooth and the wheel end, respectively, at the beginning and at the end of processing, in addition, when determining P ₀ and α ₀ for the upper cutter, the “+” sign is used in the formulas, and for the lower one, the “ - ", (see drawing No. 06-2519-4013 __________, KAMAZ OJSC, ____ g.).

The principle of operation of these mills is described in the literature: Production of gears. Ed. B.A. Taitsa. Ed. 2nd, rev. and additional M: Mechanical Engineering, 1975, pp. 105 and 431. Special equipment is used for chamfering: ZiLa machines ST 1645, CT1664, the Vitebsk plant VS-320 and the company Cross Gear. Milling cutters 1 and 2 have teeth 3 separated by chip grooves 4 (see Figs. 1-3). On one side of the teeth 3 there is a main cutting edge 5 with an angle of profile α ₀ , and on the top of the teeth an auxiliary cutting edge 6. The gear wheel 7 to be machined is mounted on the mandrel and rotates about the vertical axis 8. Chamfering is carried out with continuous division of two mills simultaneously at both ends of the wheel. Mill 1 chamfers

on the upper end, and cutter 2 on the bottom. The upper and lower worm single-turn milling cutters have different axial steps, the corners of the working profile and the direction of the helical line of the teeth. For the right direction of rotation of the workpiece, the upper mill will have a left tooth direction, and the lower one will have a right one. Thanks to the changed step, each tooth of a single-turn cutter removes part of the allowance. The entire allowance is removed in one revolution of the cutter. During operation, the wheel being machined and the milling cutters rotate in concert; during one revolution of the milling cutters, the workpiece rotates by one angular step. For one revolution of the wheel, bevels are machined on all teeth.

The disadvantage of this design is the possibility of processing the chamfer only on one side of the tooth details. When machining helical wheels, this drawback does not play a role, since on these wheels chamfering is carried out only on the sharp side of the tooth. To process this spur gear with this method, it will be necessary to design two cutters, and to process both sides of the tooth in succession in two operations.

The technical problem to which the utility model is directed is to reduce the nomenclature of the cutting tool and increase the productivity of machining bevels at the ends of spur cylindrical wheels.

This problem is solved by the fact that in a single-turn worm milling cutter separated by chip grooves and located on the same turn of the worm teeth, made with the main and auxiliary cutting edges, and the main cutting edge is made on one of the side

parties, characterized in that the cutter teeth are made with an additional main cutting edge on the other side, while the main cutting edges are made with different profile angles, the value of which is determined by the dependence:

where α _{0 right., the lion} is the angle of the tooth profile of the cutter;

- calculated profile angle in the plane of the end face of the machined wheel;

h is the height of the machined tooth of the wheel;

h _{0 is the} height of the working section of the cutter;

Δl _{a is the} value by which the point on the top of the tooth of the wheel moves during the processing of one cutter tooth,

α-angle of the wheel profile;

S is the thickness of the tooth of the wheel along the arc of the pitch circle;

D is the diameter of the pitch circle of the wheel;

τ is the angular pitch of the teeth of the wheel,

in addition, the thickness of the teeth is a variable that increases from the first tooth to the last, and the thickness of the first tooth of the cutter is equal to the circumferential width of the cavity of the workpiece, and the difference in tooth thickness is expressed by the dependence:

where z ₀ is the number of teeth of the cutter;

### U402 is the linear dimension of the chamfer, while the value of the axial pitch, measured between the center lines of the teeth, is equal to the circumferential pitch of the wheel along the arc of the pitch circle.

The execution of two main cutting edges on each cutter tooth in combination with a variable tooth thickness allows the chamfer to be machined on the adjacent sides of two adjacent gear teeth without additional feed movement, which makes it possible to use these cutters on existing equipment. The use of mills of this design will allow the machining of chamfers on spur cylindrical wheels continuously, without dividing, as in the case of machining with finger mills, and in addition to process chamfers at both ends simultaneously, which ensures high processing performance.

The applicant does not know worm single-turn milling cutters for chamfering with the specified set of essential features and the claimed set of essential features does not follow explicitly from the current level of technology, which confirms the conformity of the claimed technical solution to the condition of "novelty".

The claimed technical solution is illustrated by drawings, where:

figure 1-mill worm single-turn (prototype);

figure 2 is an external element A in figure 1;

figure 3 is a diagram of the processing of chamfers single-thread worm mills;

4 is a single-turn worm milling cutter for chamfering;

5 is an external element A in figure 4;

6 is a diagram for determining the angle of the profile of the cutter;

Fig.7 is a view of Fig.6.

A single-screw worm mill for chamfering at the ends of the gear teeth contains teeth 1 located on one turn of the worm and separated by chip grooves 2. Each tooth has two main cutting edges 3 and 4 on the sides of the tooth, and an auxiliary cutting edge 5 on the top of the tooth. The main cutting edges 3 and 4 have different profile angles α _{0 right} and α _{0 left} respectively for the right and left

the sides of the tooth cutters, the value of which is determined by the dependence:

where α _{0 right., the lion is the} angle of the tooth profile of the cutter;

- calculated profile angle in the plane of the end

the processed wheel;

h is the height of the machined tooth of the wheel;

h _{0 is the} height of the working section of the cutter;

Δl _{a is the} value by which the point on the top of the tooth of the wheel moves during the processing of one cutter tooth,

α is the angle of the workpiece profile;

S is the thickness of the tooth of the wheel along the arc of the pitch circle;

D is the diameter of the pitch circle of the wheel;

τ is the angular pitch of the teeth of the wheel,

the sign "+" or "-" in the formula for the profile angle of the cutter is selected according to the table:

Tooth Cutter Side Upper mill Lower cutter Right "+" "-" Left "-" "+"

in addition, the thickness of the teeth 1 is a variable that increases from the first tooth to the last, and the thickness of the first tooth of the cutter is equal to the circumferential width of the wheel cavity S _0per = e,

where e is the width of the depression of the workpiece along an arc of a dividing circle, and the difference in tooth thickness is expressed by the dependence:

where: z _{0 is the} number of teeth of the cutter;

### U402 -linear bevel size,

the value of the axial pitch, measured between the center lines of the teeth, is equal to the circumferential pitch of the wheel along the arc of the pitch circle P ₀ = P _t , where: P _t is the wheel pitch along the arc of the pitch circle.

The process of chamfering at the ends of cylindrical spur gears of the inventive single-turn worm mill is as follows.

Processing is carried out with continuous rotation of the machined wheel and cutters. Moreover, in one revolution of the cutter, the wheel will turn by one angular step. The first cutter tooth, having a thickness equal to the width of the wheel cavity, does not remove the allowance, but passes into contact with the adjacent lateral sides of the adjacent wheel teeth. The teeth of the mill 1 are located on one turn of the worm, so each subsequent tooth of the mill is displaced relative to the previous one in the axial direction, this leads to the fact that during one revolution of the mill its teeth enter the same cavity of the wheel. The allowance is removed from two adjacent sides of the adjacent gear teeth at the same time, by increasing the thickness of the cutter teeth. Moreover, the chamfer is finally formed by the last tooth of the cutter.

Claims (1)

Single helical worm mill for chamfering, having teeth divided by chip grooves and located on the same turn of the worm, made with the main and auxiliary cutting edges, the main cutting edge being made on one of the sides, characterized in that the milling teeth are made with an additional main cutting edge on the other side, the main cutting edges are made with different profile angles, the value of which is determined by the dependence:

where α _{0 right., the lion} is the angle of the tooth profile of the cutter;

- calculated profile angle in the plane of the end face of the machined wheel; h is the height of the machined tooth of the wheel; h ₀ - the height of the working section of the cutter; Δl _a is the value by which the point on the top of the tooth of the wheel moves during the processing of one cutter tooth; α-angle of the wheel profile; S is the thickness of the tooth of the wheel along the arc of the pitch circle; D is the diameter of the pitch circle of the wheel; τ is the angular pitch of the teeth of the wheel, in addition, the thickness of the cutter teeth is a variable that increases from the first tooth to the last, and the thickness of the first tooth is equal to the circumferential width of the cavity of the machined wheel, and the difference in tooth thickness is expressed by the dependence:

where z _{0 is the} number of teeth of the cutter; ƒ is the linear size of the chamfer, the value of the axial pitch, measured between the center lines of the teeth, is equal to the circumferential pitch of the machined wheel along the arc of the pitch circle.