SU876391A2 - Method of working surfaces of parts - Google Patents

Description

(54) METHOD FOR TREATING DETAIL SURFACES

one

The invention relates to the processing technology of spur gears and can be used in engineering and other industrial fields.

According to the main author. St. N 632554 discloses a method for machining parts such as gears, according to which gears mounted in pairs are placed in a rotating container with a working medium and rotation is reported to them at different speeds and magnitudes, and the speed of rotation of the container is chosen between 1J gears.

 However, this method does not provide high-quality machining of helical spur gears, since a curved impact occurs when a curvilinear tooth surface meets a stream of balls moving in a horizontal plane. As a result, the flow of balls thrown by a gear that rotates at a higher speed will be directed at an angle to the horizontal. In this case, if the gears are installed at the same height, the tooth portion along the width of the wheel will practically not be processed. It is significant

reduces the effectiveness of using this method for helical spur gears, as the untreated part of the tooth limits the transmission radius for wear.

The purpose of the invention is to expand the technological capabilities of the known method due to the possibility of machining helical helical gears.

This goal is achieved by the fact that, in the method of processing the surfaces of parts, the pair of gears located parallel to each other are set relative to each other with an offset FIO height, which is determined depending on the angle of inclination of the tooth line and the normal modulus by the following relation

 4p (0k)

15

where c. - coefficient taking into account the participation in the work of several

20 teeth and depending on the module of gear wheels (s 1, -2.5); b S is the distance between gears (S 4-15 mm);

(3 - the angle of inclination of the tooth line ;.

K - coefficient of impact recovery,

selectable by reference material. Such an installation of helical cylindrical gears ensures uniform processing of the teeth over the entire width of the wheel, which expands the technological capabilities of the known method of processing the surfaces of parts.

The drawing shows the layout of a pair of helical gears in a container.

The machinable non-matching helical gears 1 and 2 are installed in container 3 with the working medium in pairs with a shift in height h relative to each other. Work can be done, for example, on an eight-spindle machine. At the same time different installation gears

height is provided by the design of the mandrels. The process parameters are determined from the condition of uniform efficient processing of the entire complex curved working surface of the gear tooth. The sizes of the balls are chosen to be minimal, based on the fact that their radaus fit freely into the surface of the tooth. For different gears, the ball diameter is up to 10 mm. The speed of the ball should be such that it provides the maximum intensity of the process, but would not lead to over-hitting the surfaces of the teeth. Balls, depending on the purpose of the treatment, can be metal, glass, porcelain, etc.

Spacing between gears. a small module, taking into account the fact that the balls have, for example, a diameter of 0.5-2 mm must be 4 mm, and the value of the coefficient c for these conditions is assumed to be 1.1-1.5. For gears with a large modulus, the maximum distance is respectively 15 mm, and the coefficient value is 1.5-2.5.

During processing, the gear wheel, rotating at a higher speed, captures some volumes of the balls with its hollows, while the layers of balls adjacent to these volumes are involved in the rotation. At the time of passage of the narrowest point with the mating gear, the rotating volumes of the balls are compacted. Due to the inclination of the teeth, the compacted flow of balls, directed by the gear at an angle to the horizontal, has a dynamic effect on the processed surface of the tooth along its entire length, strengthening it. If, in addition to balls, to introduce abrasive powder into the working medium, then there will be an intensive removal of asperities, rounding of sharp edges, removal of burrs, etc. The associated rotation of the gears, as well as a change in the magnitudes of the speeds for pairs of gears and a change in the direction of rotation of the container, provide

.uniform processing of a complex curved tooth surface throughout its entirety. At the same time, the greatest intensification of the process is achieved with a difference. 15-20 times the rotational speed of the bogwheels and the rotational speed of the container lying between the speeds of the Chester gear, keeping the condition Vi Vi V or V V3 Vi,

where Vi is the speed of rotation of one gear Vj - the speed of rotation of the other gear OUSE - the speed of rotation of the container.

The rotation of the container ensures the general mixing of the balls and their constant return to the initial state, therefore, the speed of its rotation should be average between the speeds of the two gears. If the speed of rotation of the container is greater than the speed of rotation of the gears, this will reduce the intensity of processing, since rotating the container will give the balls a certain overall direction of movement that will prevail. The rotation of the gears in this case will not provide the necessary dynamic impulse.

The processing sequence, for example, on an eight-spindle machine, is as follows: the gears are set in pairs on the mandrels of the spindles with a height offset h relative to each other, turn on the rotation and oscillation of the container, turn on the rotation of the spindles and lower the gears on the ball medium. After 1/8 of the cycle, the rotation of the spindles is stopped, the reverse of the 11 shifts is switched and the speed of their rotation is changed.

Example. The final hardened helical gears made of steel 12HNZA with a normal modulus mj 3 mm and the angle of inclination of the tooth line 10 ° 15 are subjected to hardening. After cementation and hardening, the gears have a hardness of HRC 58-60. The machining is performed on a vertical duplex aggregate machine of the SKB-1 design with steel shot with a diameter of 1.5 mm known (without height displacement) and the proposed methods. The rotational speed of the machined teeth is 100Q and 60 rpm, and the rotational speed of the drum is 180 rpm. Processing time 15 min. The gears are set at a distance of 8–6 mm, the height offset is h 5.5 mm.

As a result of processing, the hardness of the teeth increased to HRC 62-63. Moreover, if during processing by the proposed method, the increase in hardness was along the entire length of the tooth, then during processing by a known method at a length of 3-6 mM at the end of the wheel this increase was practically not observed.

Thus, the proposed method of processing reduces the teeth of gears and the increase in the limit of their endurance by 15-25%,.

Claims (1)

1. USSR author's certificate N 632554, cl. B 24 B 3U06, 1977.