RU2750438C1 - V-belt variator pulley with curved generatrix - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: v-belt variator pulley consists of a movable and fixed halves and a limiting sleeve. The surface of the pulley, which interacts with the belt and transmits the torque from the driving pulley to the driven one by means of friction forces, is made of a curved shape to increase the area of the contact spot with the side surface of the belt, which is deformed under the action of tension forces.

EFFECT: efficiency of the device is increased.

1 cl, 2 dwg

Description

The present invention relates to the field of mechanical engineering and can be used mainly as a transmission element for driving land vehicles.

From the existing prior art, the design of a continuously variable transmission with an increased range of gear ratios is known (see patent RU 2716396, publication date 03/11/2020) containing a housing, a reverse mechanism, a differential, a variator transmission. The driven pulley of the variator transmission consists of two sections moving in the axial direction relative to each other by means of a spline connection and a locking device to limit the axial movement of the pulley, which is connected to the driven shaft, transmitting rotation to the reverse mechanism using a gear connection and a differential installed in rolling bearings in the gearbox housing for driving the drive wheels. The disadvantage of the known variator design is the rectilinear generatrix of the pulley, which does not provide a sufficient contact area, efficiency and, due to the uneven distribution of pressures in the contact zone, leads to rapid belt wear.

The objective of the invention is to develop the design of critical elements - variator pulleys for land vehicles, providing a higher contact area and efficiency in comparison with analogues.

The technical result achieved by the invention consists in the implementation of the following technical solutions:

- transition from a rectilinear generatrix of a pulley to a curved one;

- uniform distribution of friction forces in the contact zone and reduction of contact pressure on the central part of the side surface of the belt.

To achieve the specified technical result, the following design of the variator transmission actuator is proposed (Fig. 1)

The design consists of two halves of pulleys: movable 1 and stationary 2, located coaxially and moving translationally along the axis of the shaft. To restrict the movement of the movable half of the pulley, a bushing 3 is provided. Surface 4 is intended for contact with the side surface of the belt and for transmitting torque from the driven belt to the leading one by means of friction forces. To maintain the belt tension, there is a surface for installing the spring 5.

The proposed design works as follows:

- радиус изгиба ремня под нагрузкой,

- угол дуги изгиба ремня,

- координата измерения деформации в поперечном сечении ремня,

- угол клина ремня в рассматриваемом положении, x - горизонтальная координата точки профиля,

- радиус дуги ремня в средней линии. В результате чего боковая поверхность ремня, которая контактирует со шкивом принимает криволинейную форму. Для того чтобы увеличить площадь контакта и КПД передачи необходимо чтобы поверхность шкива имела такую же образующую. Были произведены теоретические расчеты и выведены параметрические уравнения образующей шкива:When the belt is tensioned, deformation occurs in its cross section (Fig. 2). The main parameters that can be used to describe this deformation are:

- bending radius of the belt under load,

- the angle of the arc of the bend of the belt,

- coordinate of measurement of deformation in the cross-section of the belt,

is the angle of the belt wedge in the position under consideration, x is the horizontal coordinate of the profile point,

- radius of the arc of the belt in the center line. As a result, the side surface of the belt, which is in contact with the pulley, takes on a curved shape. In order to increase the contact area and transmission efficiency, it is necessary that the pulley surface has the same generatrix. Theoretical calculations were made and parametric equations of the pulley generatrix were derived:

- радиус кривизны ремня в рассматриваемой точке, в зависимости от координаты высоты

;Where

- the radius of curvature of the belt at the point in question, depending on the coordinate of the height

;

- коэффициент снижения деформаций и напряжений при изгибе ремня.

- coefficient of reduction of deformations and stresses during bending of the belt.

Коэффициент Пуассона (для каучука равен 0,47);

Poisson's ratio (for rubber is 0.47);

- ширина ремня в деформированном состоянии.

- width of the belt in a deformed state.

Claims (6)

The V-belt variator pulley, consisting of a movable and stationary halves, a restrictive sleeve, a pulley surface that interacts with the belt and transmits torque from the driving pulley to the driven pulley using friction forces, is curved to increase the area of contact with the lateral surface of the belt, which is deformed under the action of tensile forces, characterized in that the parametric equations of the pulley generatrix are as follows, the parametric equations of the pulley generatrix:

Where

- the radius of curvature of the belt at the point in question, depending on the coordinate of the height

;

- coefficient of reduction of deformations and stresses during belt bending;

Poisson's ratio (for rubber is 0.47);

- width of the belt in a deformed state.

Images