RU220240U1 - Front-wheel drive tricycle with tilting suspension of the two rear wheels - Google Patents

Abstract

The utility model relates to the field of mechanical engineering, in particular to wheeled vehicles - tricycles. Simplification and optimization of the design is achieved due to the drive to the front steering wheel mounted on a motorcycle fork and the suspension of the two rear wheels, providing increased resistance to rollover on its side, and reducing the width of the tricycle in the front projection by providing tilting of the entire vehicle or part of it by balancing, similar to a two-wheeled motorcycle, and/or forced tilts through a power drive, as well as by changing the thrust vector of the front drive towards the turn, optimizing the impact of the gyroscopic effect and eliminating skidding of the rear wheels.

Description

Field of technology to which the utility model relates

The utility model relates to three-wheeled vehicles (tricycles).

The purpose of the utility model is to improve the technical and operational qualities of vehicles due to:

Optimization and simplification of the tricycle design through the use of a drive on the front steering wheel mounted on a motorcycle fork. Providing increased resistance to rollover on its side and the possibility of reducing the width of the tricycle in the frontal projection due to (1) the use of a suspension of the two rear wheels, providing tilting of the vehicle through balancing, similar to a two-wheeled motorcycle and/or forced tilting through a power drive, as well as due to ( 2) changing the thrust vector in the direction of turning and eliminating skidding of the rear wheels thanks to the use of a motor-wheel mounted on the front motorcycle fork. Reducing or eliminating design flaws inherent in analogues.

State of the art

There are several known analogues of narrow vehicles - tricycles, developed by global automakers, as well as the MK-17 tricycle, developed, implemented and tested by A.A. Kazartsev (patent of the Russian Federation No. 2669712), who is also the author of this utility model.

1. Toyota “i-Road” (Fig. 1). Electric tricycle with cabin. It has two front wheels with motor wheels located in them and a small diameter rear steering wheel. Tilts are provided by tilting suspension of the front wheels with a power drive of the tilting mechanism. Disadvantages: (1) two motor-wheels are used, which leads to the need to complicate the control system of the power plant due to the use of two controllers of electric motors and a balancing system for the operation of electric motors, (2) the tilting front suspension is combined with two motor-wheels, which complicates the design of the tricycle, (3) A complex steering system with a rear steering wheel is used.

2. BMW “Simple” (Fig. 2.) - a tricycle with a cabin. The tricycle has a power plant with an internal combustion engine and can be considered an analogue due to the use of a tilting suspension of the rear wheels. The front wheel is a steering wheel, mounted on a motorcycle fork. Disadvantage: the tilting suspension is combined with two driven rear wheels, which complicates the design of the tricycle and does not solve the problem of skidding of the rear wheels.

3. “Carver” (Fig. 3): a tricycle with a body tilting together with the front steered wheel in the direction of the turn, which is provided by the Dynamic Vehicle Control (DVC) system. It has a different concept of active stabilization, in which the cabin tilts relative to the massive non-tilting stern. Disadvantages: (1) the DVC system is combined with two driven rear wheels, which complicates the design of the tricycle, (2) the Dynamic Vehicle Control (DVC) system is structurally unable to provide a sufficient degree of stability at high speeds and under significant external influences, therefore, when reducing the width of the tricycle in frontal projection, the developers were forced to limit the speed to 50 km/h.

4. MK-17 (Fig. 4). The tricycle has a power plant with an internal combustion engine and can be considered an analogue due to the use of a tilting suspension of the front wheels with a power drive for tilting. It has two front steering wheels mounted on a tilting suspension. Disadvantage: The tilting front suspension is combined with an automobile steering mechanism of the two front wheels, which complicates the design.

5. Patent US 9381940B2. (US 9381940 B2 (DAVID ANDREW GALE) 07/05/2016. This patent describes a number of implementations of a tilting vehicle, including two modes of operation: in forced tilt mode and in balancing mode. The described designs differ from those given in this description.

Difference #1. US Pat. No. 9,381,940 B2 does not provide structures that can operate in both forced tilt and free balancing modes. Only separately.

In all figs. 1-31 US 9381940 B2 and the description corresponding to these figures show designs that include several different suspension options.

In the embodiment of FIG. 12, 13 US 9381940 B2 the structure cannot function in forced tilt mode. This is due to the fact that the forced tilt mode is proposed to be carried out only due to the power drive, despite the fact that the front wheel is disconnected from the steering wheel and rotates freely around the Z-Z axis.

In the embodiments of FIGS. 14, 15 US 9381940 B2 the above structures cannot function in balancing mode both due to the suspension geometry and due to the transfer of the driver’s weight. For more information, see the “Front Steering Wheel Drive, Design and Stability Factors” section below.

In the embodiments of FIGS. 16-24 US 9381940 B2 shows designs that cannot function in balancing mode. These structures ensure that the vehicle tilts in the direction opposite to the required one (car suspension).

The remaining figures from the list of figs. 1-31 and the description corresponding to these figures demonstrate either general types of vehicles or elements that do not interfere with the implementation of forced tilt or free balancing modes.

Difference No. 2. In US 9381940 B2 there is no mention of a motor - wheel, and, therefore, “Optimization of the gyroscopic effect” is impossible (see below). The mention of a front-wheel drive, which is found in US 9381940 B2, cannot be considered identical to a motor-wheel, since it implies many implementation options.

Difference #3. US 9381940 B2 makes no mention of a motorcycle fork. The only design similar to a motorcycle fork is shown in Fig. 12, 13, however, it differs from it in that the steering wheel is disconnected from the front wheel due to the operation of the pin Fig. 13 pos. 316, 318, which makes it impossible to operate in the declared modes. There are no other mentions of steering that allows balancing due to suspension geometry similar to a motorcycle, and Figs 14, 15 show steering options that exclude this method of balancing.

6. Patent US 9845129 B2 (FORD GLOBAL TECHNOLOGIES LLC) 12/19/2017, column 3, line 23 - column 12, line 38, fig. 1-8. This patent only covers tilt suspension options and does not mention combinations of these suspensions with front-wheel drive steering wheels.

7. Patent RU 2323845 C1 (ZAVALISHIN OLEG IVANOVICH and others) 05/10/2008, from page 4, line 24 to page 6, line 29, fig. 1, 2. This patent describes a rear-wheel drive vehicle with a significantly different suspension of the rear wheels, which cannot be considered an analogue, as follows from the name, formula and description of this utility model.

Disclosure of utility model

Optimization and simplification of design

The tilting tricycle or quadricycle has three of the most complex components (in order of decreasing complexity):

1. suspension providing tilts,

2. steering mechanism,

3. power plant.

In electric tricycles, the electric motor and controller may be structurally more complex than the steering mechanism, but the use of motor-wheels allows us to consider the power plant as two simple non-separable structural components: the motor and the controller. Each of these components can be installed on a vehicle as simply as possible and maintained during operation.

On the other hand, the tricycle motorcycle front fork and steering wheel are a simpler component compared to the car front suspension and steering mechanism, which makes it easier to use on tricycles.

In this regard, the optimal layout of a tricycle dictates the combination of the two simplest of the three complex components: (1) the front fork and motor-wheel and (2) a separate placement of the suspension that provides tilting of the tricycle.

The proposed vehicle has the following set of essential features:

1. Front-mounted electric motor-wheel, combined with a front motorcycle fork (Fig. 5, item 1);

2. Rear-mounted suspension (Fig. 5, item 2) of two wheels (Fig. 5, item 3), providing increased resistance to tipping on its side and reducing the width of the tricycle in the front projection compared to a tricycle with a conventional suspension (Fig. 5, item 4) by providing tilting of the entire vehicle or part of it;

The relationship between the width of a non-tilting vehicle and its lateral stability is disclosed in the Interstate Standard GOST 31507-2012, page 6, which provides a formula relating the track width of a vehicle to its lateral stability. To provide lateral stability to narrow vehicles such as motorcycles, suspension designs are used to allow the vehicle to tilt. The operation of such structures and the stability of vehicles are influenced by a number of factors that can be minimized or, conversely, maximized by introducing certain structural elements into the design. Stability factors and suspension design elements used in this utility model are given below.

Front steering wheel drive, design and stability factors

Essential factors for the stability of a two-wheeled or other motorcycle that tilts during turns while riding are:

1. gyroscopic effect of wheel rotation,

2. balancing through suspension geometry,

3. transfer of the driver’s body weight,

4. use of a power drive for the tilt mechanism.

One of the objectives of this development was to minimize the driver’s transfer factor to insignificant values and minimize the use of the power drive of the tilt mechanism.

To do this, it was necessary to strengthen and optimize the influence of the first two sustainability factors.

The initial parameters for determining the stability of the balancing vehicle were selected in accordance with section 3 [1],

According to [1], the geometry of the suspension determines the radii of the wheel, the shoulders of application of the acting forces and other parameters during linear motion and the values of Fig. 8.

In practice, the slope is illustrated in Fig. 9, pos. 1, 7. (the numbering corresponds to Fig. 8), where it is shown that when the steering (steered) wheel is turned, the distance from the axis of rotation of the wheel to the point of contact with the surface changes due to the offset of the fork (trail) and the radius profile of the wheel tire. Radius when turning pos. 7, radius during linear movement pos. 1.

The greater the fork offset value (trail), the greater the stabilizing moment when moving, on the other hand, the greater the fork offset value, the more difficult it is to return the steered wheel to its original position, since the energy costs for returning the steered wheel to its original position are equal to:

,

where h can be equal to the values of pos. 6 or 7, and R is the lateral reaction arm of pos. 4 or 5, Fig. 8.

Then the work done by the driver when balancing will be:

To increase the fork offset (trail) and balancing efficiency, you can shift the longitudinal axis of the front fork by an amount of 8 (Fig. 8) forward relative to the vertical axis of symmetry of the wheel, however, the practical implementation of a balancing suspension has shown that this is not necessary.

The diagram for changing the position of the plane of rotation of the steered wheel when turning with an inclined fork is shown in Fig. 10, the numbering of parameters corresponds to Fig. 8.

The angle of inclination YA of the plane of rotation of the steered wheel A relative to the horizontal plane depends on the angle of rotation of the steered wheel Qd, the angle of inclination of the front steered fork B (item 3. Fig. 8) and changes according to the following law:

In this case, with an increase in values 6 and 7 (Fig. 8), the restoring moment decreases, since the values 9 and 10 decrease and reach zero at Qd = 90°.

Therefore, in the practical implementation of the suspension balancing mode, adjustable rotation limiters of the steering (steered) wheel were used.

Optimization of the gyroscopic effect. During the practical implementation of this useful model, several prototypes of tricycles with tilting suspension with rear and front wheel drive were tested. A significant gyroscopic effect was achieved by the fact that all designs used electric motor-wheels with significant weight.

When testing a tricycle with a rear-mounted two motor-wheels, it was experimentally established that when the tricycle tilts, the gyroscopic effect of the motor-wheels counteracts the tilt and tends to return the wheels to a vertical position. This is due to the fact that the front steering wheel, which does not have an electric motor, is lighter than the rear wheels. Tilt and balancing in this design is carried out due to the “fork extension” of the steering wheel, which is also called the “lateral reaction arm” in Russian-language technical literature, and “trail” pos. in English-language technical literature. 1 fig. 8. The greater the fork offset (trail), the more intense the vehicle is tilted and balanced, which, on the other hand, leads to greater effort to return the steering wheel to its original position (for details, see the list of references, No. 1, pp. 70-71) .

The slope is illustrated in Fig. 8, pos. 2, 3, where it is shown that when the steering wheel is turned, the distance from the axis of rotation of the wheel to the point of contact with the surface decreases due to the offset of the fork (trail) and the radius profile of the wheel tire. Radius when turning pos. 2, radius during linear movement pos. 3.

In addition to the size of the fork stem (trail), the kinetic energy of the steering wheel affects the balancing efficiency due to the suspension geometry. Thus, when turning and balancing on a rear-wheel drive tricycle, it is easier for the driver to turn the steering wheel and return it to its original position due to the counteracting gyroscopic effect of the heavy rear wheels, but the efficiency of tilting and balancing is significantly reduced.

In addition, when tilting is performed while the tricycle is turning, another anti-tilting and turning effect occurs due to the gyroscopic effect of the heavy rear wheels. Rear wheels do not turn Fig. 11 pos. 2 around a vertical axis and are always located parallel to the body of the tricycle FIG. 11 pos. 1. Thus, the gyroscopic effect of the rear wheels counteracts not only the tilt but also the turning of the tricycle.

When testing a tricycle with a front wheel motor, the gyroscopic effect, on the contrary, helped the tricycle tilt due to the suspension geometry, and the influence of the gyroscopic effect of the two rear wheels was significantly reduced, since they did not have heavy motor wheels. In addition, the gyroscopic effect of the heavy motor-wheel in the front steering wheel helped the tricycle turn, since when turning, the front steering wheel not only tilts, but also turns in the direction of the turn along the vertical axis. Thus, the gyroscopic effect of the front motor wheel was optimally manifested in the vertical (turn) and horizontal (tilt) planes (Fig. 12). In addition, when riding a rear-wheel drive tricycle, balancing and turning are carried out mainly due to the suspension geometry, counteracting the gyroscopic effect of the rear wheels, and when combining the front steering wheel with an electric motor, balancing and turning are additionally assisted by the driver turning the steering wheel. Thus, balancing and turning become significantly more efficient compared to rear-wheel drive. The downside to these positive effects is that the driver needs to apply more steering force when turning and balancing. However, according to test engineers, this force does not exceed the threshold where turning and balancing becomes uncomfortable for a person of average weight, height and physical fitness.

Therefore, in the practical implementation of the utility model, there is an electric motor in the front wheel, which has a significant mass.

An additional significant factor in increasing stability was that the front-wheel drive design eliminated the effect of skidding of the rear wheel(s). Skidding of the rear wheel (wheels) is a common cause of motorcycle falls due to the fact that at the moment the turn begins, the thrust vector of the rear wheels (wheels) is directed towards the movement of the motorcycle before the turn begins, while the direction of movement of the front steering wheel has already changed towards turn. In contrast, the thrust vector of the front steering wheel motor is directed towards the turn from the moment the turn begins, and the thrust vector of the rear wheels is absent (Fig. 12).

Thus, a practical result was achieved in which, by (1) optimizing the use of the gyroscopic effect (direction and plane) and (2) maximizing the effect of the suspension geometry (trail), the need to transfer the driver's weight was reduced to minimum values that can be neglected in practice as a factor in ensuring the stability of the tricycle. Since it is impossible to effectively transfer the driver’s weight inside a closed cabin, this was the determining factor in the practical implementation of the utility model.

Disclosure Conclusion

The rear suspension of a tricycle can have any design, and tilting can be achieved through free balancing and a power drive. An essential feature of the utility model is the front location of the motor-wheel, combined with a front motorcycle fork and a rear tilt suspension.

Front-wheel drive mounted on the steering wheel improves the stability of a motorcycle (tricycle) when cornering due to (1) directing the thrust vector of the power drive towards the turn, (2) optimizing the impact of the gyroscopic effect of the front motor wheel by changing the plane and vector of rotation of the gyroscope, as well as (3) preventing the rear wheel(s) from skidding.

Implementation of a utility model

A tricycle with the design described above was built and tested (Fig. 6, 7), which confirmed the technical result experimentally. The tricycle was tested together with analogue 4 and showed a significant increase in controllability and resistance to rollover due to: (1) front-wheel drive in combination with a steering mechanism, (2) rear-mounted tilt suspension, (3) general optimization and simplification of the design.

References

1. V.V. Gaevsky, Doctor of Technical Sciences, Prof., “Development of the theory of movement of single-track vehicles, Monograph” Moscow Automobile and Highway State University (MADI), Moscow, 2019.

Claims (1)

A three-wheeled vehicle with a wheel motor mounted on a front motorcycle fork and a suspension of the two rear wheels that allows the vehicle to tilt by balancing, similar to a two-wheeled motorcycle, or forced to tilt by a power drive, which together provide increased sideways rollover stability and reduced the width of the tricycle in frontal projection.