Planetary gearbox with toothed belt

Abstract

FIELD: mechanical engineering.SUBSTANCE: planetary gearbox with a toothed belt comprises an input shaft mounted with the possibility of rotation on an input shaft support, and an output shaft adapted for rotation on an output shaft support coaxially with the input shaft. A three-beam planet carrier is rigidly secured to the output shaft. A central toothed pulley is rigidly secured to the input shaft, and toothed satellite pulleys are mounted at the ends of the three-beam planet carrier adapted for rotation, which are engaged with the central toothed pulley and with the toothed belt. The input shaft support and the output shaft support are rigidly secured to a fixed base, and the toothed belt is secured from rotation by means of a rocker arm, the upper end of which is fixed to the toothed belt, and the lower end of which is fixed to a fixed base.EFFECT: planetary gearbox combines elements of a gear transmission and a belt drive, characterized by a high load capacity with a small weight, as well as a low noise level during operation.1 cl, 3 dwg

Description

[0001] The invention relates to mechanical engineering, in particular to mechanical transmissions containing a toothed belt, as well as toothed pulleys that perform planetary motion.

[0002] A differential planetary belt drive system (US Patent 6,113,509 A - analogue) is known, comprising planetary pulleys mounted on a support structure that rotate around the motor shaft, while the support rotates around the motor shaft. A first planetary pulley is connected by a drive belt to a fixed pulley. The fixed pulley does not rotate and is coaxial with the motor shaft, so the planetary pulley rotates during orbital motion. A second planetary pulley rotates with the first. The output pulley is connected to the second planetary pulley by another drive belt, and the output shaft is connected to the output pulley. The device is characterized by low noise levels due to the use of belts instead of meshing gears, but has a low load-bearing capacity due to the kinematic connection of the satellites to the central pulley via belts.

[0003] A planetary mill (RU Patent No. 107490) is known, comprising a carrier mounted cantilevered in bearing supports on an axle. The carrier carries sleeves, which are cantilevered to the carrier. Shafts are mounted within the sleeves in bearing supports. Grinding drums are mounted cantilevered at one end of the sleeves. Satellite toothed pulleys or satellite gears are attached to the opposite ends, meshing with sun toothed pulleys or sun gears via toothed belts. The device is characterized by low noise levels, but, in fact, is not a gear transmission. Furthermore, the kinematic connection between the central or sun toothed pulley and the satellite toothed pulleys is realized by toothed belts, which limits the load capacity of the device.

[0004] A planetary gearbox with involute sprockets is known (RU Patent No. 2850016 - prototype), comprising an input and output shaft, a pinion, and a carrier, at the ends of which satellite sprockets are mounted for rotation and engaged with a closed chain. The pinion has involute external teeth and is rigidly attached to the input shaft, which is mounted for rotation on the input shaft support, while the carrier is three-beam and rigidly attached to the output shaft, which is mounted for rotation on the output shaft support coaxially with the input shaft. Moreover, the satellite sprockets are sprockets with involute teeth, engaged with both the chain and the pinion. In this case, the chain is a single-row roller chain and is fixed from rotation by means of a pin rigidly fixed on one of the chain links with the possibility of vertical longitudinal movement along a groove made in the support of the input shaft.The device boasts a high load-bearing capacity due to the direct engagement of the central pinion with the involute satellite sprockets. However, the use of a roller chain increases the device's weight and is a source of noise during operation due to the impact of chain links with the sprocket teeth.

[0005] The objective of the proposed invention is to create a toothed belt transmission with a coaxial arrangement of the input and output shafts, characterized by a high load capacity with a small weight, as well as a low noise level during operation.

[0006] The technical result is the creation of a planetary gearbox that combines elements of a gear transmission and a belt transmission equipped with a rubber-fabric or polyurethane toothed belt.

[0007] The technical result is achieved by a planetary gearbox with a toothed belt (hereinafter referred to as the gearbox), comprising an input shaft mounted for rotation on an input shaft support, and an output shaft mounted for rotation on an output shaft support coaxially with the input shaft. A three-beam planet carrier is rigidly attached to the output shaft. Moreover, a central toothed pulley is rigidly attached to the input shaft, and toothed satellite pulleys are rotatably mounted at the ends of the three-beam planet carrier, which are in mesh with the central toothed pulley and with the toothed belt. Moreover, the input shaft support and the output shaft support are rigidly fixed to a fixed base, and the toothed belt is secured from rotation by means of a rocker arm, the upper end of which is secured to the toothed belt, and the lower end of which is secured to the fixed base.

[0008] Fig. 1 shows a planetary gearbox with a toothed belt at the extreme upper position of the pantograph. Fig. 2 shows a planetary gearbox with a toothed belt at the extreme upper position of the pantograph (side view). Fig. 3 shows a planetary gearbox with a toothed belt at the extreme lower position of the pantograph.

[0009] A planetary gearbox with a toothed belt comprises an input shaft 1 mounted so as to rotate on an input shaft support 2, and an output shaft 3 mounted so as to rotate on an output shaft support 4 coaxially with the input shaft 1. A three-beam planet carrier 5 is rigidly fixed on the output shaft 3. Moreover, a central toothed pulley 6 is rigidly fixed on the input shaft, and toothed satellite pulleys 7 are mounted so as to rotate on the ends of the three-beam planet carrier 5, which are in engagement with the central toothed pulley and the toothed belt 8. In this case, the input shaft support 2 and the output shaft support 4 are rigidly fixed on a fixed base 9, and the toothed belt 8 is fixed from rotation by means of a rocker arm 10, the upper end of which is fixed on the toothed belt 8, and the lower end is fixed on the fixed base 9.

[0010] The gear reducer works as follows.

[0011] Input shaft 1 rotates together with central toothed pulley 6 (Fig. 1). By means of toothed engagement, rotation is transmitted from central toothed pulley 6 to toothed satellite pulleys 7, which, while rotating, roll on toothed belt 8, causing three-beam planet carrier 5 to rotate together with output shaft 3. Moreover, toothed belt 8 does not rotate, since it is fixed relative to fixed base 9 by means of rocker arm 10, which allows toothed belt 8 to move only in the vertical plane (Fig. 1, 3) when changing the position of toothed belt 8 relative to the shaft axes. Thus, toothed belt 8 performs the function of a fixed ring gear with internal teeth in the planetary mechanism, on which toothed satellite pulleys 7 roll.

[0012] In this case, the gear ratio determined by the dependence is realized

[0013]

[0014] where z1 is the number of teeth of the central toothed pulley 6, W3 is the number of teeth of the toothed belt 8.

[0015] The direct toothed engagement of the central toothed pulley 6 with the toothed satellite pulleys 7, as well as the multi-pair engagement of the teeth of the toothed belt 8 with the teeth of the toothed satellite pulleys 7 on their arcs of engagement ensures the high load capacity of the gearbox.

[0016] Thus, the proposed planetary gearbox with a toothed belt will ensure a high load capacity with a coaxial arrangement of the input and output shafts, and the elimination of the use of a roller chain will significantly reduce the weight of the device and reduce noise during operation.

Claims

A planetary gearbox with a toothed belt, comprising an input shaft mounted so as to rotate on an input shaft support, and an output shaft mounted so as to rotate on an output shaft support coaxially with the input shaft, wherein a three-beam carrier is rigidly fixed on the output shaft, characterized in that a central toothed pulley is rigidly fixed on the input shaft, and toothed satellite pulleys are mounted so as to rotate on the ends of the three-beam carrier, which are in engagement with the central toothed pulley and with the toothed belt, wherein the supports of the input and output shafts are rigidly fixed on a fixed base, and the toothed belt is fixed from rotation by means of a rocker arm, the upper end of which is fixed on the toothed belt, and the lower end is fixed on a fixed base.

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