Articulated frame to UAZ.
Overview of the structures of "breaking" frames.

To the average person, the phrase "breaking frame" is associated with a heavy breakdown of a truck or SUV.

However, there is engineering solutions, which are specially designed for such an opportunity to "break" the frame without consequences :).
This is done to increase the cross-country ability and maneuverability of the car.

Back in 1919 Italian engineer Pavesi designed the Fiat-Pavesi P4 high-traffic tractor with very large wheels. To turn the car, the principle of a "breaking" frame was implemented. (source - patriot4x4.ru)

In our country, in 1961, on the instructions of the government, a Tractor K-700 with broken frame. The aim of the project was to create the first domestic wheeled tractor of the fifth traction class. In the photo, the K-701 tractor

The semi-frame of the K-700 tractor has impressive dimensions

Assembly drawing of the connecting hinge of the tractor K-700

And who does not remember the city articulated bus Ikarus-280?

The unique properties of cars with a breaking frame have inspired many designers to implement such a solution in various types of all-terrain vehicles. Moreover, both single-homemade, and on an industrial scale.
Here at least remember the Swedish caterpillar swamp An elk that has many imitators.
But in the ranks of wheeled vehicles there is something to see:

Snow and swamp vehicles SKU

SKU snow and swamp vehicles, which were produced by the Severodvinsk company Diphthong, have two sections interconnected by a rotary coupling device, which allows the links to fold relative to each other in a horizontal plane.
Snow and swamp vehicles are described in the magazine Autoreview for 2006

Photo of a swivel

Photo showing that it is necessary to make a turn limiter

Tractor "Sibiryak"

An articulated frame is installed on the Siberian

The most interesting is the central hinge assembly.
It consists of a power housing, which is the rear part of the front half-frame, a constant velocity joint (CV joint), which transmits torque to the rear axle, and a spherical body, hinged and power.
The ball shank is inserted into a special housing of the rear half-frame and has the ability to rotate in it when the relative position of the half-frames changes. A special body is connected to the rear half-frame with two 20 mm plates.

Power case, welded from sheets 20 mm thick. perceives the loads acting on the machine in the vertical plane, and the ball bearing, fixed in the tapered bearings of the housing, serves to rotate the half-frames relative to each other in the horizontal plane.
This movement is carried out by a hydraulic cylinder of the turn, installed between the front half-frame and the ball bearing bracket.

Parts from knuckle front wheel car ZIL-131 identical in design to the car GAZ-66, but differing in size.
The shank of the ball housing and the shanks of the semi-axes of the drive and driven shafts of the CV joint have been revised.
Bearings in the axial joint are bronze bushings, and traction (longitudinal) forces are perceived by a thrust ball bearing. The hinge cavities are sealed with glands and filled with grease.

Central hinge:
1 - bearing 60212; 2- pin M10 (6 pcs.): 3, 10 - thrust rings (steel 45, s2). 4 - king pin; 5 - cuff (from a standard unit); 6 - spring ring; 7 -- cuff (1-115x145); 8 - liners (bronze): 9 - spacer; 11 - thrust nut; 12 - bearing 8212; 13 - locking nut; 14 - special case; 15 - body of the central ball-hinge assembly; 16 - ring; 17 - driven shaft; 18 - ball body; 19 - drive shaft; 20, 26 - bearing housings (steel 45). 21 - flange (cram. 45) 22 - M32 nut; 23 - hairpin M5 (6 pcs.); 24 conical bearing (standard); 25 - bearing cover: 27 - sealing ring (rubber); 28 - cuff (1-85x110); 29 - steering hydraulic cylinder.

Often, swivel assembly for all-terrain vehicles they are made from the steering knuckle of the front wheel of an all-wheel drive vehicle, for example, from a UAZ steering knuckle

UAZ-camper with a twisting frame

Using the technology that was worked out on the Corporals, UAZs with a twisting frame were made. This is a camper based on the Krasnodar auto club "Kuban" and a truck based on the UAZ-39095

In FIG. 1 shows a view of the vehicle in plan; in fig. 2 the same, side view; in fig. 3 scheme of bearing unloading.
The articulated vehicle 1 with all-wheel drive contains two independent semi-frames A and B, interconnected with the possibility of relative movement. Between the semi-frames, the main hinge 2 is installed, having an inner diameter 3 sufficient for free passage through it cardan shaft 4.
On the semi-frame B, coaxially with the bearing 2, a movable element 6 is installed on the brackets 5 (for example, a shaft mounted in bearings, or a ball joint, or a ball connector) can be used as element 6, rotating around axis 7. bars 8 and 9. The second ends 10 of the bars are detachably fixed on the connecting elements 11 of the semi-frame A. The ends of the bars 10 are spaced apart from the longitudinal axis of the vehicle 7.

Vehicle works as follows.
When driving off-road, semi-frames A and B can move around the horizontal longitudinal axis one relative to the other at an angle of up to 23°. The possibility of mutual movement is provided by the hinge 2, which connects the half-frames A, the rods 8 and 9, rotating on the element 6 and tracking the movement of one half-frame relative to the other, unload the hinge 2 and increase its working area (see Fig. 3). The resulting longitudinal force loads between the half-frames A and B are perceived primarily by the connectors 8 and 9, since they are rigidly connected (without backlash), are partially extinguished due to their own elasticity, and then transferred to the hinge 2.

When driving on public roads, the load-bearing frame works in the same way as when driving off-road, taking maximum loads and unloading hinge 2.

The hinge in the non-working position is fixed with pins on both sides, which allows the car to move comfortably on public roads. (the pins are removed in the photo)

Blueprints

Inside the hinge (bearing) passes cardan on rear axle and all communications:
wires, brake pipes, air hoses.

This design was initially tested on a utility vehicle UAZ-VD "VARAN"

It was built for fishing trips, picking berries and mushrooms. The author tried to use the most available parts to save money, so that the all-terrain vehicle was budget. The all-terrain vehicle was built by the author together with his father, who was engaged in all welding work.

Materials and units used to build this all-terrain vehicle:
1) bridges from the car Moskvich 412
2) FDD engine with forced air cooling
3) steering knuckle from Oise
4) reverse gear from FDD
5) additional chain reducer
6) steering from m-41
7) VI-3 lightweight wheels
8) profile pipe
9) hub from vaz 2108

Let us consider in more detail the stages of construction and the main components of the all-terrain vehicle.

To begin with, two semi-frames measuring 1600 by 700 were welded from a profile pipe. rover bridges were installed in the middle. And also a frame fracture unit was made from the UAZ steering knuckle according to the Uvat scheme.

After that, work began on the creation of disks for the all-terrain vehicle. The design of the disks was made as simple and reliable as possible. The diameter of the locking rings is 510, although 530 was originally planned. True, this did not play a strong role.

Then the author began work on the back of the semi-frame.

Then the marking of the main elements and their layout in the all-terrain vehicle began. In particular, the author decided to see where it is better to install the engine subframe.

At the same time, work continued on individual designs of the all-terrain vehicle. a cardan shaft was made, which transmits rotation from the gearbox to the hub of the VAZ 2108, and then through the sprocket to the cardan shaft of the Muscovite bridge.

The main turning work was commissioned by a specialist in this business.

Below you can see how the hub is connected to the Muscovite shank.

Then it was installed steering rack from m-41. The rail was installed according to the Uvat scheme:

It shows how it was fused Tie Rod from Oise and m-41:

Welding work on the front half-frame of the all-terrain vehicle was carried out:

The gearboxes in the bridges of the Muscovite were turned over, and a gearbox from the FDD was also installed.

After the gearbox was disassembled, the author welded a differential in it and proceeded with the assembly, followed by installation in its place in the design of the all-terrain vehicle.

After the two front wheels of the all-terrain vehicle were completed, the author decided to install the roof:

On the backs, a 40 x 25 profile with a thickness of 2 mm was used. moreover, a cut was made on the last upper profile in order to be able to put on the ring. On the front two wheels, the lower profile of the same size is 40 by 25 and 2 mm thick, and the upper one is 30 by 30 mm. The creation of the front wheels was much simpler and the wheel was easy to put on, unlike the design of the rear wheels.

After completing the main work on the transmission of the all-terrain vehicle, the author proceeded to field tests of the vehicle. after the first tests, some flaws in the design of the all-terrain vehicle were revealed. In particular, they consisted in the incorrect operation of the all-terrain vehicle clutch, as well as gear shifting. Therefore, the author began to refine the transmission from the engine to the gearbox and clutch. For this, the original motorcycle clutch cable was replaced, as it squeezed too hard, which did not give a smooth gear shift. It was also installed on the all-terrain vehicle exhaust pipe to reduce the noise of the machine.

Materials and units involved in the construction of this model of an all-terrain vehicle:
1) engine internal combustion Lifan 15 hp
2) Four-speed gearbox from the classic VAZ
3) Transfer case from a Niva car
4) Fist rotary from Oise
5) Wheels t-150 stripped

Let us consider in more detail the main components of the design of this all-terrain vehicle.

The fracture node was created from the knuckle according to the Uvat scheme.

Two profile B belts are installed, as well as a small pulley for 100 and a large pulley for 300:

Wheel rims were created from T-150 rims, which were wrapped in iron 2 mm thick, and also tack welded along the perimeter. The very fastening of the tire to the disk is done with the help of locking wheels, also with inside welded beads that hold the tire. the tire itself is put on the disc with an interference fit, which gives even more fastening strength, plus the author used a sealant. Whether such fastening is enough will be shown by tests.

A frame was made from a profile pipe by welding, and bridges from the VAZ 2105 were also installed on the frame, the gear ratio is 4.1:

Initially, the author wanted to make landing on the hub on his own, but it turned out to be quite difficult and unreliable, so I had to invest more funds into an all-terrain vehicle.

The weight of the all-terrain vehicle itself in the assembled state is 550 kilograms. The author also began to prepare the all-terrain vehicle for swimming.
The mounts to the axle shafts have been painted so that you can immediately notice cracks if they do not pass the test. Although the design should not fail, since the washers are scalded on both sides and this should be enough according to the calculations.

Steering was installed. The steering rack was taken from the VAZ 2110, but its stroke is too small and this is not enough for convenient control of the all-terrain vehicle. Therefore, in the future, the author plans to either replace it or install an additional lever to correct the direction of movement, as well as increase the stroke.

Then the steering knuckle and the rear half-frame were fastened in this way:

To create a turning unit, a fist from an UAZ was used.

Further, the author considered two ways to create an all-terrain vehicle transmission.
First, you can remove transfer case and install a chain reducer, then the speed will decrease, but the chains become additional vulnerable spot an all-terrain vehicle that will need to be worked on.

you will have to shorten the frame, and make a more balanced weight distribution of the front of the frame.
Secondly, if you leave the transfer case, you can simply replace the gearboxes with cheap ones with gear ratio 4.3. In this case, we also get a decrease in speed, but not as much as we would like.

Regarding weight distribution, there is a possibility front axle cut off and lift the shank higher, so as to move the structure almost close to the transfer case, it is not entirely clear only about the oil level in the gearbox and how this will affect the operation of the system. It may also be worth disassembling the transfer case itself in order to reduce the number of downshifts, but this requires a serious approach to the study of technical documentation.

Also, to strengthen the turning unit, it is planned to install a couple of shock absorbers from the Zil:

The all-terrain vehicle was left in the sun outside the garage, the sun heated the tires of the car and it spontaneously disassembled, which is rather unpleasant and indicates insufficient reliability of the tires.

Urgent measures were taken to strengthen the fastening:

The steering rack was turned over, and a node that was destroyed under loads was added, after these actions it became much more convenient to steer.

Yes, the design is rather weak and not reliable, but for some time it will work and it will be possible to test the machine.
The role of the clutch in the all-terrain vehicle is performed by two belts. During a trip on an all-terrain vehicle, one of them flew off for an unknown reason, the author decided not to put it back in the field, but simply remove it and drive to the garage on one belt. It was noticed that an all-terrain vehicle with one belt feels much better, a smooth ride appeared, and most importantly, it starts moving without jerking.

Regarding the destructible structural element, it was made in this way: one bolt was removed, and the edge was twisted onto aluminum wire, due to which, under loads, it will simply bend the rods relative to each other. It is also quite convenient to regulate the load force by simply increasing or decreasing the number of turns of wire.

During the tests, the steering rod broke off, so this element also needs to be improved.
For example, installing a pump from a steering yamz 236.238, since it was immediately made for profile A, instead of nsh-10.
Silent means consent! I'm really sure that installing these (similar) aggregates will make your life much easier. Instead of NSh-10, it is easier to use the pump from the steering YaMZ 236.238, it is immediately made for the profile A belt (if I'm not mistaken)

Photo nsh-10, weighing 2.5 kilograms:

Steering system weighing 4 kilograms:

Hydraulic cylinder weighing 5-7 kilograms:

It is also planned to install bridges on springs to reduce shock loads on the transmission structure itself, which will increase the speed and smoothness of the all-terrain vehicle. It is possible to modify the hinge by replacing the steering knuckle with three supports and a spacer, although the frame articulation assembly fully withstands the load and justifies itself.

But with the wheels there are really difficulties.

The wheels turned out to be very heavy, weighing about 85 kilograms with the disk. In addition, there is no central path - the all-terrain vehicle shakes. So in the future, the author plans to replace them with other lighter ones.

The author also wants to remove the transfer case from the field and install a chain gearbox. There is another reason why the author wants to get rid of the transfer case, this is the speed of the all-terrain vehicle. On first low gear the all-terrain vehicle is moving at a speed of approximately 5 kilometers per hour, and this is on idling engine. This is certainly tolerable, but still too much for the minimum speed, too much load will go to the bridges and the engine itself when overcoming difficult obstacles.