RU2677813C1 - Continuously variable transmission with planetary mechanism “a+b” - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: invention relates to the continuously variable transmissions with power division. Continuously variable transmission contains the variator and the planetary transmission (PT). In the continuously variable transmission housing (1) supports the input shaft (2) is located, on which the gear rim (3) is fixed and the drive bevel gear (4) with the gear rim (5) is freely installed, clutch (6) is located on the input shaft (2) gear rim (3) for connection to the drive bevel gear (4) gear rim (5). On the input shaft (2) a large friction wheel (7) is fixed, a small friction wheel (8) is pressed thereto, movably mounted on the PM sun gear (11 (a)) drive shaft (10) key (9). Drive bevel gear (4) is engaged with fixed on the shaft (13) driven bevel wheel (12). On this shaft the engaged with the driven cylindrical wheel (15) driving cylindrical gear (14) is fixed. This wheel is fixed to the epicyclic wheel (17 (b)) housing (16), which is engaged with the mounted on the carrier (20 (h)) axles (19) and engaged with the sun gear (11 (a)) satellites (18). Carrier (20 (h)) is fixed on the output shaft (21) with the gear rim (22), installed perpendicular to the input shaft (2). Epicyclic wheel (17 (b)) housing (16) is mounted on the tubular shaft (23) with a gear rim (24). On the continuously variable transmission housing (1) the PM locking or the epicyclic wheel (17 (b)) stopping gear rim (25) with clutch (26) is located.EFFECT: enabling the LTS layout and operational capabilities expansion.1 cl, 2 dwg

Description

The invention relates to the transmission of the NTS (land vehicles), etc.

Known are simple three-link PM (planetary mechanisms), which are often used as single-stage wheel gears, when one link is stopped, torque is applied to the sun gear, and removed from another link, for example, from the carrier (1. Car: Design Basics: Textbook for high schools on a specialty "Automobiles and automobile economy" / NN Vishnyakov and other M .: Mashinostroenie, 1986. - 304 S. p. 158, Fig. 123); as two-stage gearboxes (1. p. 123, Fig. 95, b). Simple three-link PMs are also used in planetary gearboxes in which torque is supplied to the sun gear and removed from the epicyclic wheel (1. p. 122, fig. 94, d; p. 143, fig. 108).

The advantages of planetary gearboxes (gearboxes) compared to gearboxes with fixed gear axles are the ability to obtain large gear ratios with a small number of gears, as well as lower weight and overall dimensions, but planetary gearboxes have a higher cost (1. p. 123 )

Simple three-link PMs can provide 7 gears in gear modes and 3 gears in summing (integral) modes when torque is supplied to two links and removed from the third. The use of PM in summing modes in combination with a basic step gearbox can significantly increase the gear ratio range of the resulting transmission unit compared to the base gearbox. This solution was used in technical solutions for gas pumping units according to RU patents (2: No. 2397344. Bull. 23 dated 08/20/2010. No. 2581269. Bull. No. 11 dated 04/20/2016. No. 2583476. Bull. No. 13 dated 05/10/2016. Authors V.I. Nekrasov and I.A. Ivanov).

The considered designs realize a stepwise transformation of the torque, which leads to a decrease in the operational properties of the NTS due to the disruption of the power flow when shifting gears.

Stepless friction gears are known - frontal variators, consisting of two friction wheels pressed against each other, one of them can be moved along the shaft key. (1.p. 130, fig. 100, b).

Stepless transmissions are known that include a friction variator and a planetary gear operating in a summing (integral) mode.

Closest to the proposed device is a continuously variable transmission (3. Patent No. 2166138; F16H 15/50). The continuously variable transmission comprises a housing, primary and secondary parallel shafts, a lever, a lever rotation control mechanism, a drum with a multi-disc friction variator of the internal contact. The output shaft and planetary adder are additionally introduced into the transmission. The sun gear of the planetary adder is mounted on the output shaft located coaxially with the primary (input) shaft.

This continuously variable transmission has inherent disadvantages: a multi-plate friction variator operates in high load mode, since the main part of the torque passes through it to the PM carrier. The loads in the PM are distributed in proportion to the radii of the PM links, with the minimum load coming to the sun gear (1. p. 123). In the device according to patent No. 2166138, the PM sun gear is fixed on the output shaft and is loaded with the maximum (total) torque. The multi-plate friction variator has a complex structure, it is located in the drum 18, which is kinematically connected with the control mechanism of rotation of the lever 19 (3. Fig. 2). PM is used only in the summing mode; PM capabilities are much wider.

The objective of the invention is to expand the layout and operational characteristics of the NTS due to the simplification of the design of a stepless friction variator, the greater realization of the PM capabilities when transforming and transmitting torque in gear and summing modes, both without breaking the power flow and when the variator is turned off.

The technical result is achieved by improving the technical solution for patents No. 2166138; 2397344 and others by installing a stepless friction gear - a simple frontal variator that transfers only a small part of the torque to the sun gear, and the main power flow is transmitted by a cylindrical gear to the PM epicyclic wheel.

The achievement of the technical result is ensured by the fact that the continuously variable transmission contains a friction variator and a simple three-link planetary mechanism consisting of a sun gear, an epicyclic wheel and a carrier with satellites, while the input and output shafts are installed perpendicularly, on the input shaft next to the gear ring and the clutch a leading bevel gear is installed, which interacts with the epicyclic wheel with a driven bevel wheel, shaft and a cylindrical gear, ohm fixed shaft also large friction wheel, low friction wheel is mounted on the spline shaft of the sun gear and the actuator is pressed against the large frictional wheel; the carrier is mounted on the output shaft, the gear ring of this shaft is located next to the gear rims of the tubular shaft of the epicyclic wheel housing and the continuously variable transmission housing.

In FIG. 1 shows a kinematic diagram of a continuously variable transmission with a frontal friction variator and a simple three-link PM (planetary gear) in the “ a + b” mode with a perpendicular arrangement of the input and output shafts.

In FIG. 2 shows the kinematic characteristics of continuously variable transmissions. On the abscissa axis the values of the gear ratio of the variator are plotted - U _var , on the axis of the ordinates are the gear ratios of the continuously variable transmission - U _out .

In the bearings of the housing 1 of a continuously variable transmission (Fig. 1), an input shaft 2 is located on which a gear ring 3 is fixed and a bevel gear 4 with a gear ring 5 is freely mounted, a coupling 6 is located on a gear ring 3 of the input shaft 2 for connection with a gear ring 5 a leading bevel gear 4. A leading large friction wheel 7 is fixed to the input shaft 2, a driven small friction wheel 8 is pressed against it, which is movably mounted on the key 9 of the shaft 10 of the drive of the sun gear 11 ( a ) PM. The drive bevel gear 4 is engaged with the driven bevel gear 12, which is fixed to the shaft 13, the drive gear gear 14 is fixed to this shaft, which is engaged with the driven gear wheel 15. This wheel is mounted on the housing 16 of the epicyclic wheel 17 (b), which engaged with the satellites 18 mounted on the axles 19 of the carrier 20 (h) and engaged with the sun gear 11 ( a ). The carrier 20 (h) is mounted on the output shaft 21 with a gear ring 22 mounted perpendicular to the input shaft 2. The casing 16 of the epicyclic wheel 17 (b) is mounted on the tubular shaft 23 with a gear ring 24, which is located next to the gear ring 22. On the housing 1 continuously variable transmission next to the ring gear 24 is a ring gear 25 with a clutch 26 lock PM or stop the epicyclic wheel 17 (b).

A simple PM consisting of three links: the sun gear ( a ), the epicyclic wheel (b) and the carrier (h) with the satellites, is characterized by an internal parameter K = Z _b / Z _a = 1.5-5, which is equal to the ratio of the numbers of teeth Zb epicyclic wheel and Z _a sun gear.

The summarizing capabilities of PM for our case are described by the dependence:

n _h = U _ha ^b n _a + U _hb ^a n _b = n _a / (K + 1) + (n _b K) / (K + 1);

where n _a , n _h , n _b is the rotation frequency of the sun gear, carrier and epicyclic wheel in rpm.

The operation of the gearbox is as follows. PM can work in several modes. Let's start with simple mode.

Gear mode U _ah ^b = K + 1

The upper index "b" indicates a stopped link PM - epicyclic wheel 17 "b", the indices below - the links of the input " a " - the sun gear 11 ( a ) and the output "h" of torque - drove 20 (h). If you take K = 4.0; then the rotation frequency of the carrier 20 (h) and the driven shaft 21 will be 5 times less than the rotation speed of the sun gear 11 ( a ), which is determined by the rotation frequency of the input shaft 2 and the gear ratio of the variator 7-8.

In FIG. 1, the drive to the epicyclic wheel 17 (b) from the input shaft 2 is disconnected by the coupling 6 (see the right view), the epicyclic wheel 17 (b) is stopped by the coupling 26 (see the upper position), which closed the gears 25 of the housing 1 and 24 of the tubular shaft 23 the casing 16 of the epicyclic wheel 17 (b). Torque from the input shaft 2 is supplied to the large friction wheel 7, then to the small friction wheel 8, along the key 9 to the shaft 10, to the sun gear 11 ( a ) and the satellites 18. If the wheel 8 is in the extreme left position, then the variator works in accelerating mode - U _var <1,0. In the position shown in FIG. 1, the variator operates in a decelerating mode - the force is transmitted from a small diameter to a large diameter. If U _var = 1.5; then the gear ratio of the device will be U _D = U _var U _ah ^b = 1.5 × 5 = 7.5; it is marked with T. D on the upper line 1 of FIG. 2. With further movement of the wheel 8 and the intersection of the center of rotation of the wheel 7, the direction of rotation of the shaft 10, the sun gear 11 (a) will change and then to the output shaft 21.

Summing operating mode PM

n _h = U _ha ^b n _a + U _hb ^a n _b = n _a / (K + 1) + (n _b K) / (K + 1)

In contrast to the previous mode, the torque is transmitted to the PM in two ways: to the sun gear 11 ( a ), as described earlier, the main flow of force is supplied by gears to the epicyclic wheel 17 (b).

In FIG. 1 torque to the epicyclic wheel 17 (b) comes in a bevel gear 4-12, U _con = 1,0; on the shaft 13, on a cylindrical gear 14-15, while the clutch 6 (see the left position) closes the gears 3 of the input shaft 2 and 5 of the drive bevel gear 11. The torque from the input shaft 2 along the gear ring 3 and clutch 6 is transmitted to a gear ring 5 and a driving bevel gear 4, then to a driven bevel gear 12, a shaft 13, a driving cylindrical gear 4, a driven cylindrical gear 15, an epicyclic wheel 17 (b) and satellites 18. Also, the torque from the input shaft 2 is applied to a large friction wheel 7, then on a small friction track about 8 to 9 for the spline shaft 10, the sun gear 11 (a) and the satellites 18, then the carrier 20 (h) and the output shaft 21. When a small friction wheel 8 is in the rightmost position, the variator operates in the accelerating mode, when the ratio of the diameters of the wheels 7 and 8 is equal to 5, U _var = 0.2; rotation frequency of the sun gear: n _a = n _I / U _var = 1000 / 0.2 = 5000 rpm; n _a / (K + 1) = 5000/5 = 1000 rpm; Under these conditions, the rotational speed of the carrier 20 (h) and the output shaft 21 n _h = n _a / (K + 1) + n _b K / (K + 1) = 1000 + 200 = 1200 rpm; U _K = 1000/1200 = 0.833; this result is marked by T. K on the upper gentle curve 3 of FIG. 2.

Emergency mode - variator failure

We bring the small friction wheel 8 out of contact with the large friction wheel 7, block the PM coupling 26 (the lower position of the coupling), closing the gears 22 and 24. Only cylindrical gearing 14-15 with U _cyl = 4.0 works (i.e., on the upper direct 1).

It is advisable to use the reduction mode only at low load, for example, when the NTS is empty, since the entire torque is realized by the friction contact of wheels 8 and 9. The totalizing mode of operation of the PM when changing the direction of rotation of the sun gear 11 (a): n _h = - n _a / ( K + 1) + n _b K / (K + 1) we use for loaded NTS (curved lines 4 and 5). The operation of the device in FIG. 2 with a change in the direction of rotation in the mode: n _h = n _a / (K + 1) + n _b K / (K + 1) n _{b is} not advisable - a gentle line 3 above the abscissa axis.

Changing the parameters K, U _cyl , U _con will lead to a change in the dependencies in FIG. 2.

Designations:

1 - continuously variable transmission housing;

2 - input shaft;

3 - a gear ring mounted on the shaft 2;

4 - a leading bevel gear;

5 - a gear ring of a bevel gear 4;

6 - coupling coupling with gears: 3 input shaft 2 and 5 with a bevel gear 4.

7 - a large friction wheel;

8 - a small friction wheel; 9 - key;

10 - the driven shaft of the small friction wheel 8 and the drive of the sun gear 11 (a);

11 (a) - sun gear PM;

12 - driven conical wheel;

13 - shaft driven conical wheel 12;

14 - a leading cylindrical gear;

15 - driven cylindrical wheel;

16 - the body of the epicyclic wheel 17;

17 (b) - PM epicyclic wheel;

18 - satellites; 19 - axis of the satellites;

20 (h) - carrier;

21 - output shaft;

22 - the ring gear of the shaft 21 from the carrier 20 (h);

23 - a tubular shaft of the housing 16 of the epicyclic wheel 17;

24 - the gear rim of the tubular shaft 23;

25 - gear ring of the housing 1;

26 - clutch lock PM or stop the epicyclic wheel 17.

Claims (1)

A continuously variable transmission containing a friction variator and a simple three-link planetary mechanism consisting of a sun gear, an epicyclic wheel and a carrier with satellites, characterized in that the input and output shafts are mounted perpendicularly, a leading bevel gear is freely installed on the input shaft next to the gear ring and the clutch which interacts with an epicyclic wheel by a driven bevel wheel, a shaft and a spur gear, a large friction is also fixed to the input shaft e wheel, a small friction wheel is mounted on the key of the drive shaft of the sun gear and pressed against the large friction wheel; the carrier is mounted on the output shaft, the gear ring of this shaft is located next to the gear rims of the tubular shaft of the epicyclic wheel housing and the continuously variable transmission housing.

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