RU2542838C1 - Compact mechanical multi-stage gearbox to transfer arbitrary torques without break of power flow - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: box contains drive shaft with fit seated set of pinions, set of follower gears permanently engaged with the pinions and made with possibility of free rotation around the driven shaft, and driven shaft containing gears switching coupling that permits smooth connection of the pinion and driven shaft, transition of the arbitrary torques without break of the power flow and gear switching is arbitrary order, the difference is that coupling for each gear switching can contain two or several types of machinery intended to transmit the torque that can have different design and different machinery of torque transmission, and upon each separate gear switching can be switched on with delay, thus ensuring use of their different ability for the torque transmission and sliding without damage.

EFFECT: compact and reliable design.

10 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to the field of transport engineering, to transmissions of vehicles, and more specifically to gearboxes designed for multi-stage transmission of torque from the engine to the drive wheels of the vehicle and can also be used in other areas of technology.

BACKGROUND

A known design of a dual-clutch gearbox (patent DE923402C, 1940), which allows shifting without interrupting the power flow. Modern DCT (Double Clutch Transmission) gearboxes are best known by the name of the most common DSG variant (Direct Shift Gearbox or Direktschaltgetriebe), but there are other similar in essence designs: Powershift, Speedshift DCT, TST (Twin Clutch Transmission ), EDC (Efficient Dual Clutch).

Many patents are devoted to the improvement of this scheme, for example, SU 1299842 (1984), DE 4122628 A1 (1991), WO 2003083325 A1 (2003), US 20080188342 (2007), RU 2383800 (2008), RU 2436001 (2010), RU 2437011 (2010) ), RU 2439396 (2010), RU 2442919 (2010)

All of them use the main advantage of this scheme (no disruption of the power flow when switching), but they are not spared from obvious drawbacks: a complex three or four-shaft scheme, the need for a constant change of engagement of the synchronizer clutches with gears when shifting gears, the need to predict the next gear to be switched on, and the fundamental impossibility switching without breaking the power flow through one gear and a relatively large amount of time when switching to a gear that does not stand in gear laziness and the presence of two full-fledged multi-plate clutches, each of which is designed to transmit using the friction joint the maximum torque that the engine can create. Large sizes of clutches directly affect the overall dimensions of the gearbox, and the complexity of the design - with its cost and reliability.

In patent RU 2158860 (1998) an attempt was made to simplify the design by abandoning synchronizers. Each gear is engaged with its hydraulic drive and its multi-plate clutch. This eliminates the need to predict the next gear included. The disadvantage of this solution is that the multi-plate clutch is large and several of these elements significantly increase the overall dimensions of the gearbox. This is especially important for the large torques characteristic of modern automobile engines. So that the clutch can transmit a large moment, an additional clamping sleeve with helical slots is introduced into the design, which complicates the design, reducing the positive effect of the absence of synchronizers.

The layout of the gearbox is quite complicated, and in patent RU 2287439 (2004) it is proposed to assemble all pairs of gears in a separate block with its own body, which can move along the shaft to connect with the selected pair of wheels. The disadvantage of the proposed solution is a significant increase in the overall dimensions of the gearbox, in which a place should be provided for the entire block of gears moving from one extreme position to another. The increased size of the box housing, the presence of an additional housing for the gear block will lead to an increase in the mass of the structure. Another drawback is that with each gear shift, this scheme requires moving considerable masses - the entire gear block together with the housing of this block. This complicates the drive and reduces the life of the gearbox.

Known gearbox of a vehicle (RF patent No. 2472995, 2011), not containing synchronizers and clutches. Gear shifting is done by engaging the appropriate clutch. The disadvantage of this design option is that this design uses at least 4 clutches. A five-speed gearbox, made according to the named scheme, requires six clutches. Each of the couplings must be capable of transmitting full torque. A six-speed gearbox requires the use of an additional countershaft.

A large number of clutches with a drive to each of them significantly increases the overall dimensions of the structure. Currently, a multi-plate clutch of a car may include 10-12 discs. The size of one multi-plate clutch is comparable to the size of the gearbox block. Such a scheme does not guarantee simplification of the design and reduction of material consumption and increase the compactness of the gearbox.

However, in this technical solution there are the following features:

1. Transmission clutches, forks, synchronizers are absent.

2. All pairs of gears are in constant gearing.

3. Gear shifting is done through the original use of clutches.

Therefore, we will take this technical solution as a prototype, since it has the maximum combination of essential features common with the invention.

OBJECT OF THE INVENTION

The objective of the invention is to create a more efficient gearbox of a compact size with a continuous transmission of torque from the engine to the drive wheels, to avoid restrictions on the amount of transmitted torque, to simplify control, eliminating the need to predict the next gear, to reduce the time of gear shifting with arbitrary choice of sequence gear shifting and simplify the design, increasing the reliability and efficiency of the gearbox.

SUMMARY OF THE INVENTION

COMPLETENESS OF ESSENTIAL SIGNS.

Proposed in the invention, the solution of the above problem, the achievement of the goal and the required technical result is ensured by the simplicity of the two-shaft scheme, the reliability of the constant engagement of all pairs of gears and the design of the combined clutch for engaging gears with a rational arrangement of gearbox elements.

A mechanical multi-stage gearbox is proposed, which is characterized by a combination of the in-line arrangement of the gear block and the drum construction of the multi-stage clutch of each gear integrated in the output shaft, which allows smooth connection, the transmission of arbitrary torques without breaking the power flow and the inclusion of gears in random order.

The term "arbitrary torque" means a moment of any value that the engine can transmit to the input shaft of the gearbox using known types of connections, for example splined or keyed.

The cam mechanism, which is the second additional stage of the gear clutch, is generally capable of transmitting the same torques as splined or keyed couplings.

TECHNICAL RESULT.

The proposed design of a mechanical multi-stage gearbox provides:

- Transfer of torques without interrupting the power flow during the shift due to the ability to independently switch off one gear and switch on another.

- Smooth connection when the gear is engaged due to the operation of the friction element of the combined clutch.

- Transmission of arbitrary torques due to additional mechanical gearing in the combination clutch. The ability to use the same gearbox with engines of different power.

- Compact design due to the row layout of the gear block and the placement of the coupling elements inside the gear block in the holes of the output shaft, and the drive inside the output shaft.

- Simplification of the design by replacing one transmission clutch with three clutch elements: clutch clutches, clutch gears and synchronizers.

- Reliability and unpretentiousness of a design, use of usual oil for mechanical gearboxes with gears. The design does not use either a torque converter or variator elements, which impose stringent requirements on the operating fluids and temperature conditions of operation.

- Using any of the known drive options - mechanical, hydraulic or electric, as well as a combined one.

- No need to predict the next transmission. And when choosing the appropriate drive - the inclusion of gears in random order.

A simpler gearbox design allows you to increase the number of stages and reduce engine requirements.

The proposed gearbox design determines smaller dimensions, weight, simpler drive, lower price.

This design can be used without changes both with the manual gearshift mechanism, and in robotic gearboxes.

Using a radial (drum) clamping circuit allows the most efficient use of frictional properties for transmitting torque.

The two-shaft gearbox layout and the in-line arrangement of the gear block determines the possibility of using a housing with one plane of the connector, which provides ease and convenience of assembly and maintenance of the gearbox.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by diagrams. The following notation is used in the diagrams:

1 - Leading (input) shaft.

2 - Slave (output) shaft.

3 - Drive.

4 - Intermediate gear reverse gear.

5 - Cam clutch gear.

6 - Friction pads clutch gear.

7 - Driven gear.

Section AA illustrates the section of the driven gear and the driven shaft with gear clutch elements passing through the friction clutch pads.

Section BB illustrates a section of the driven gear and the driven shaft with the elements of the gear clutch passing through the cams of the gear clutch.

In FIG. 1 shows the general layout of a multi-stage gearbox.

In FIG. 2 shows a functional diagram of the operation of the gearbox when operating in neutral gear mode (the gear shift mechanism and the gear shift drive are shown in simplified form).

In FIG. 3 shows a functional diagram of the operation of the gearbox when first gear is engaged (the gear shift mechanism and the gear shift drive are shown in simplified form).

In FIG. 4 shows a functional diagram of the operation of the gearbox when the first gear is turned off and the second gear is engaged (the gear shift mechanism and the gear shift drive are shown in simplified form).

In FIG. 5 shows a typical circuit of a combination clutch and illustrates the cross sections used in FIG. 6-9.

In FIG. 6 shows a functional diagram of a gear clutch in an off state.

In FIG. 7 is a functional diagram of the initial phase of engaging the gear clutch.

In FIG. 8 shows a functional diagram of the operation of the gearshift clutch in the on state during normal operation.

In FIG. 9 shows a functional diagram of the operation of the gearshift clutch in the engaged state when transmitting increased torque.

In FIG. 10 shows a schematic diagram of the asynchronous expansion of the friction pads and cams with a single drive.

DETAILED DESCRIPTION OF THE INVENTION

In a mechanical multi-stage gearbox comprising a housing, a drive shaft with a block of driving gears rigidly mounted on it, a driven shaft, a block of driven gears that are in constant engagement with the driving gears, made with the possibility of free rotation around the driven shaft, a multi-stage clutch is used gear shifting, which allows a smooth connection, the transmission of arbitrary torques without interrupting the power flow and the inclusion of gears in an arbitrary order. This combined clutch may contain for each transmission two or more blocks (structural elements) designed to transmit torque, which may have a different design and a different mechanism for transmitting torque and may not be included in the operation at the same time (in the simplest case, in series, one after the other), which allows them to use their various ability to transmit torque and slip without breaking.

Such a coupling can be integrated in the output shaft.

In this example, the clutch uses for each transmission two mechanisms for transmitting torque - friction and cam.

All friction pads and cams are mounted in elastic mounts, which allows damping possible shock loads.

In FIG. 5 shows a general arrangement of gearshift clutch elements integrated in the output shaft 2 and uses both friction pads 6 and cams 5 to transmit torque.

Such a clutch replaces three types of elements in a transmission: all clutches, all clutches of gear shifting and all synchronizers.

According to the invention, the operation of the gearbox is as follows.

 The drive shaft 1 (see Fig. 1) is constantly connected to the engine. The gears of the drive shaft are always rigidly connected to the drive shaft. All pairs of gears of gears are in constant gearing. Therefore, the rotation of the engine is always transmitted to the drive shaft and all gears.

The gears of all gears of the driving (input) shaft 1 rotate with the same angular speed equal to the speed of the input shaft.

The gears of all gears of the driven (output) shaft 2 rotate freely - each with its own angular speed, determined by gearing with a pair of pinion gears.

The gearshift clutch elements are integrated in the output shaft.

In the recesses (or holes) of the output shaft opposite the driven gear of each gear are friction pads and cams that can be moved apart under the influence of the drive.

In FIG. 2 illustrates the off state of the gear clutch.

FIG. 3 and FIG. 4 illustrate sequential engagement of two adjacent gears.

In FIG. 2 and FIG. 6 shows the initial (neutral) state of the clutch. Friction pads 6 and cams 5 are recessed into the corresponding holes of the output shaft 2. The driven gear 7 and the driven shaft 2 are disconnected. No torque is transmitted to the driven shaft. Transmission off. This is an analogue of neutral gear.

In FIG. 7 shows the initial stage of gear shifting. The drive begins to move apart pads and cams.

The drive pushes the friction pads and cams of the shaft opposite the gears of the desired gear.

The friction pads move apart before the cams. The pads 6 come out of the grooves of the shaft and are pressed against the inner surface of the gear and connect the shaft and gear of the corresponding gear. The created frictional joint aligns the rotational speeds of the gear 7 and the driven shaft 2. The cams 5 do not reach the surface of the gear and do not participate in the transmission of torque. The selected gear is engaged.

The output shaft rotates with the angular speed of the gear of the selected gear. In FIG. 4 and FIG. 8 shows the next stage of gear shifting.

The drive completes the process of expanding the pads and cams. Friction pads 6 are pressed against the inner surface of gear 7 with maximum force. Friction transmission transmits torque. The rotation speeds of the driven gear 7 and the driven shaft 2 are the same. Transmission is on.

The process of spreading the cams is completed and they abut against the inner surface of the gear. Cams 5 touch the inner surface of the gear only after the friction pads are fully pressed, i.e. after full inclusion in the work of friction transmission of torque. The cams are pressed by the drive to the inner surface of the gear 7 in an arbitrary place of the annular zone. In the general case, they do not engage with the corresponding protrusions on the inner surface of the gear and do not participate in the transmission of torque.

In FIG. 9 shows the state of the elements of the clutch when the gearbox is operating at high load.

The torque transmitted to the input of the gearbox exceeds the moment that the friction joint can transmit without slipping. The gear 7 is rotated relative to the output shaft 2 to the position where the cams 5 are recessed into the corresponding seats on the inner surface of the gear 7, creating the necessary mechanical connection. The resulting reliable power circuit transmits the required torque. Mutual slippage of the gear and shaft stops.

Transmission is disengaged in the reverse order. First, the cams are disengaged.

In this case, the friction gear remains fully engaged.

Only after the cams have completely sunk into their seats in the output shaft does the friction joint disconnect.

The use of the same drive for sequentially expanding the pads and cams is shown in FIG. 10.

The shown structural diagram is only an illustration of the technical feasibility and simplicity of the solution and is not an essential feature and should not be construed as a solution protected by the invention. For the implementation of the present invention, any drive and any mechanism for transmitting a control action to a torque transmission device can be used. An essential feature is that torque transmitting elements are not brought into action simultaneously.

The drive clutch can be performed using any currently known technology, for example, it can be mechanical, hydraulic, electromagnetic or combined.

The proposed design of the gearbox allows you to flexibly use the differences in the transmission of torque during operation of different gears. The maximum moments that are transmitted by lower and higher gears are very different. For larger gears, the radius of the inner surface of the gear can be increased. Thanks to the in-line layout, this will not increase the complexity of the assembly structure. It is enough to apply an output shaft of variable diameter. In this case, it becomes possible to increase the transmitted torque, both by increasing the shoulder, and by increasing the number of friction pads. This is important for low gears that transmit maximum torque. For higher gears that transmit small moments, it is possible to simplify the design by rejecting the cams and transmitting all the torque only with friction pads.

Claims (1)

A multi-stage mechanical gearbox comprising a drive shaft with a drive gear unit fixedly mounted thereon, a drive gear unit in constant engagement with the drive gears, capable of free rotation around the drive shaft, and a drive shaft comprising a gear clutch, which allows a smooth connection of the driven gear and the driven shaft, the transmission of arbitrary torques without breaking the power flow and the inclusion of gears in an arbitrary order, distinguishing the fact that the clutch of each gear may contain two or more types of mechanisms designed to transmit torque, which may have different designs and different mechanisms of torque transmission, and when each individual gear is engaged, they may not be switched on at the same time, which allows use their various ability to transmit torque and slip without breaking.

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