Variable-speed gear transmission

FIELD: mechanical engineering.

SUBSTANCE: gear transmission comprises planetary reduction gear and worm pair which engages the planetary reduction gear. Worm (1) of the worm pair is mounted for permitting rotation and axial movement along the driving shaft of the gear transmission and is kinematically connected with satellite (7) of the planetary reduction gear. Driving shaft (2) carries small central wheel (9) of the planetary reduction gear and kinematically connected with satellite (10) of the planetary reduction gear. Satellite (10) is kinematically connected with worm wheel (3). The axle of wheel (3) freely rotates around carrier (4). The axle of large central wheel (8) of the planetary reduction gear is the driven shaft of the gear transmission.

EFFECT: improved design.

1 dwg

 

The present invention relates to gears with variable speed output shaft, in particular to the transmission containing the worm with the worm wheel.

Various industries are experiencing a greater need for gears with controlled within wide limits by changing the gear ratio between the master and slave shafts. A typical solution to this problem can serve as a gear transmission mechanism, in which two parallel shafts are group of gear wheels of different diameters, serially connected to each other than in the wide variation of the transmission ratio between the shafts (see, for example, ISI. Mechanisms in modern engineering, vol, "Nauka", M., 1973, page 456).

The disadvantage of these programs is the discrete change of gear ratio, which in some cases is unacceptable.

Smooth (infinitely variable) change of gear ratio in the gear can be obtained, for example, when using snail mechanism with helical movement of the links or with spiral bevel wheel (see ibid., pp. 59 and 61, respectively). However, in such mechanisms it is impossible to produce an intermediate gear ratio between its extreme values.

In light of the above shortcomings in the technique to smoothly change the gear ratio of the kinematic used mainly by frictional transmission (hydraulic and electric tools of change of gear ratio, using other conversion tool, this application will not be considered).

All friction gear with their structural diversity based on the General principle of operation is the transmission of torque through frictional interaction pairs, such as "Automatic continuously variable transmission" under the patent of Russia, having got NO 2091637, F 16 H 15/50, which taking into account the authority of its Creator can be considered the most progressive in the art. However, as with all other friction gear, it has a common drawback - transmits torque through frictional interaction elements, which are characterized by slippage, sensitivity to the purity of the interacting surfaces, the service life is limited by the choice of material of the friction elements, and so forth

For the prototype of the claimed invention can be selected gear of the planetary gear with the worm gearing on Its, vol, page 480, which by its very nature, though, and will not transfer with variable speed, but in essential structural characteristics most similar to the claimed invention.

The mechanism includes a worm gear, a worm shaft which is leading, and on the shaft of the worm wheel rigidly mounted small Central gear of the planetary gear, it is the abuser outer teeth. Small Central wheel is connected by satellites with large fixed Central wheel having teeth. Drove satellites serves as the driven shaft of the mechanism.

The mechanism has an inherently conventional two-stage gearbox with a large gear ratio (first stage worm gear, the second planetary) and may not change the gear ratio between the master and slave shafts.

Before the claimed invention was tasked to create an infinitely variable gear transmission to change gear ratio between the master and slave shafts can be locked in any gear ratio between its extreme values.

The problem is solved in that the proposed gear containing a worm gear, the shaft of which is a leading transmission shaft associated with the planetary including a carrier carrying at least two satellites, interacting with a small Central gear external gear and a large Central gear internal gear planetary gearbox.

New in the proposed transfer is that a worm mounted on the shaft with the possibility of free rotation and forced axial displacement and kinematically associated with one satellite planetary gearbox and shaft with others who shM satellite, kinematically connected with the worm wheel, the axis of which is freely rotationally mounted on the driver satellites, with the axis of the rotationally mounted large Central wheel is driven transmission shaft, coaxially to the presenter, and the worm communicates with the control pressure bearing.

The technical result of the claimed device is to create a gear transmission with a continuously variable controlled by changing the gear ratio between the master and slave shafts can be locked in any gear ratio between its extreme values.

The drawing shows a kinematic diagram of the declared transmission.

The requested transfer contains a worm gear pair, the worm 1 which is mounted on the shaft 2 with the possibility of free rotation and axial movement (mixing). The axis “O” of the worm wheel 3, which interacts with the worm 1, is mounted on a drive rod 4 of the planetary gear. The worm 1 through the cylindrical gears 5 and 6 are kinematically connected to one of the satellites 7, which engages with the internal teeth of a large Central wheel 8 of the planetary gear. The worm shaft 2 through a small Central gear wheel 9 and the other satellite 10 is also associated with a large Central wheel 8 of the planetary gear. In turn, the satellite 10 is kinematically connected with drawing cnym wheel 3, for example, a pair of bevel wheels 11.

In contrast to the known planetary gearboxes large Central wheel 8 is mounted for rotation, the shaft 12 is driven transmission shaft.

The transmission has a pressure bearing 13 acting in the axial direction of the worm 1. Broadly stated, the transmission consists of two gear - worm and planetary kinematically associated with each other.

Before describing the operation of the declared transmission in General should clarify the interaction of some of its elements.

Worm pair. It is well known that during transmission of rotation from the worm to the worm wheel to the worm leads to a large axial load equal to the district force on the worm wheel. Specified axial load on the worm is a lack of worm pairs.

In the claimed transfer this lack of worm pairs becomes its advantage, as applied to the worm through pressure bearing 13 axial load is governing, which is converted to a circumferential force on the worm wheel. As a result, the worm wheel there is a moment of resistance to rotation, which is a bevel pair 11 and the satellite 10 is transmitted to the large Central wheel 8. When the moment of resistance to rotation of the Central wheel 8 will exceed the torque load is on the output shaft 12, the latter will start to rotate.

Planetary gearbox. In the declared transmission planetary gear in a veiled form is a summing mechanism. The General principle of any aggregation mechanism (for example, the well-known differential) is that when the two shafts leading to its driven shaft will rotate with variable speed up to a full stop depending on the speed and direction of the leading of the shafts.

In light of the described known features of worm pairs and summing mechanism will consider the work of the declared transmission in the two extreme cases.

The first case. The worm 1 and worm wheel 3 are, relatively speaking, in a non-contact interaction. This is possible when the worm and wheel are rotated from independent actuators synchronously. In this case, the worm wheel will get independent rotation from the drive shaft 2 through a kinematic chain, containing the bevel gear 9, the satellite 10 and a pair of bevel wheels 2. With a stationary Central wheel 8 satellite 10 starts in our teams on internal teeth of a large Central wheel 8, pulling drove 4, i.e. simultaneously with the rotation of the worm wheel 3 its axis "O" will receive from the carrier (and with him), the spatial rotation of the worm 1. At the same time drove the 4, pulling another satellite 7, will begin to run its internal teeth of the gear 8. Rotating the satellite 7 through gears 6 and 5 will rotate the worm 1 synchronously with the rotation of the worm wheel 3, i.e. the interaction of the worm 1 and the wheel 3 will be, relatively speaking, contactless due to their independent synchronous rotation (friction between the teeth of the worm and wheel is missing). The synchronicity of their rotation is provided by the corresponding gear ratio of gear elements in their kinematic drive chain. The speed (frequency) of rotation of the driven shaft 12 will be zero.

The case of the second. By application of axial load on the worm 1 (through pressure bearing 13) he will move before coming into contact with the teeth of gear 3 (load directed against the direction of rotation of the wheel 3). When the corresponding axial force will occur "jamming" of the worm and wheel, i.e. the wheel 3 relative to the axis "O" will be blocked. Obviously, in this case, stop the rotation around its axis and the satellite 10, which, ceasing to our teams on the internal teeth of the gear 8 will start to rotate it together with the planet carrier 4. Lock relative ("normal") of rotation of the wheel 3 and the worm 1 will also cause the termination of the test satellite 7 in the teeth of the wheel 8, ie 7 satellite like the satellite 10 will engage the wheel 8, rotating it instead of the e with the planet carrier 4. Thus, at full lock rotation of the worm wheel 3 relative to the axis "O" of the rotational speed of the driven shaft 12 will be equal to the frequency of rotation of the drive shaft 2.

It is easy to understand that between the extreme values of the rotational speed of the driven shaft 12, driven or non-contact interaction of the worm 1 and the wheel 3, or by a mutex, you can get any desired rotational speed of the driven shaft 12 by changing the axial thrust on the worm 1 (changing its axial displacement by means of the control pressure bearing 13).

It should be noted that the friction between the teeth of the worm 1 and the wheel 3 is in no way equivalent to the friction of the friction elements in a well-known variable-speed drives, as between the teeth of the worm and wheel in the declared transmission friction does not exceed produced when the well-known worm pairs, i.e. does not exceed their normal operating loads (the same applies to the pressure bearing 13). Moreover, if a well-known worm paired with the increased speed of the driven shaft increases the rate of slip between the teeth of the worm and wheel and correspondingly decreases transmission efficiency due to friction losses in the declared transmission on the contrary, with the increase of frequency of rotation of the driven shaft 12 of the speed of the relative slip between the teeth of the worm and the wheel falls, prezelin the m value becoming zero (respectively disappear friction losses) and transmission efficiency increases.

Based on the above stated transfer to a first approximation could be attributed to the timing of the variator, but in full it would be illegal because the declared transmission loses some well-known properties of the variable.

Thus, the characteristic feature of the well-known variable is the increase in torque on the driven shaft with a decrease in the frequency of its rotation. Announced the transfer of this property does not have, because the torque on the driven shaft depends on the gear ratios in its kinematic chains, which remain unchanged in the process, and torque on the driven shaft may not exceed the torque on the master. However, in many areas of technology require gear that need stepless change speed output shaft, and the change in torque is not necessary.

For example, currently a big problem is a change in the process, the rotation speed of the induction motor alternating current, massively used in the technique. Today, this sophisticated thyristor control systems, changing the mains frequency (the frequency of rotation of the magnetic field on the stator). The weight and dimensions of these systems often exceed veagara itie characteristics of the controlled motor, not to mention the complexity of their service.

The declared transmission in combination with the known asynchronous AC motor allows a simple means to obtain a manageable variable speed rotation of the shaft (in special cases, the application of feedback between the number of revolutions of the driven shaft and the force of the pressure control bearing).

Gears with variable speed, containing the planetary gear and cooperating worm gear pair, a worm which is mounted with the possibility of controlled axial displacement, characterized in that the worm is mounted freely rotationally with the possibility of controlled axial displacement of the drive shaft of the transmission and kinematically associated with one satellite planetary gearbox, and a drive shaft carrying a small Central wheel of the gearbox, with a different satellite, kinematically connected with the worm wheel, the axis of which is freely rotationally mounted on the driver satellites, with the axis of the rotationally mounted large Central wheel gear is driven transmission shaft.



 

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FIELD: mechanical engineering.

SUBSTANCE: gear transmission comprises planetary reduction gear and worm pair which engages the planetary reduction gear. Worm (1) of the worm pair is mounted for permitting rotation and axial movement along the driving shaft of the gear transmission and is kinematically connected with satellite (7) of the planetary reduction gear. Driving shaft (2) carries small central wheel (9) of the planetary reduction gear and kinematically connected with satellite (10) of the planetary reduction gear. Satellite (10) is kinematically connected with worm wheel (3). The axle of wheel (3) freely rotates around carrier (4). The axle of large central wheel (8) of the planetary reduction gear is the driven shaft of the gear transmission.

EFFECT: improved design.

1 dwg

FIELD: transport engineering.

SUBSTANCE: invention relates to drives of all-wheel-drive cross-country vehicles designed for riding along roads and off-road. Proposed two-step planetary transfer case contains upper planetary reduction gear providing two speeds of transfer case, intermediate shaft with gear 5 and lower planetary reduction gear being essentially differential drive for rear and front driving axles. Driving member of upper planetary reduction gear is crown gear 9 stationary connected with drive shaft 8, driven member is carrier 13 and controlled member is central gear 11. Gears of upper planetary reduction gear, driving gear 4, intermediate gear 5 and driven gear 6 and gears of lower differential mechanism are arranged in one row one over the other.

EFFECT: reduced overall dimensions adapted for mounting transfer case on vehicles.

1 dwg

FIELD: transport engineering.

SUBSTANCE: proposed wheel has rim of regular shape and center of rotation. To drive the wheel, planetary reduction gear is fitted in wheel rim whose drive gear is planet pinion installed on driving "floating shaft whose axis, taking weight of vehicle applied to wheel, executes complex movement relative to axis of wheel rotation making it possible to: 1) spread projections of axis of rotation (being simultaneously point/line of support) of wheel and point of application of vehicle weight P to wheel on horizontal surface by some distance L; 2) change position of projection of point P on vertical; plane by some height h and provide constantly acting "canting" torque PL on wheel creating effect of eccentric wheel at wheel circumference remaining unchanged and eliminating cyclic loads.

EFFECT: improved cross-country capacity of vehicle, its steerability, efficiency of wheeled propulsor, simplified design.

1 dwg

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