Among the cars there are examples that embody the history of society. One of these machines is the SZD motorized stroller as an intermediate link between a motorcycle and a full-fledged car.
Today, the SZD motorized stroller can only be exhibited at a vintage car show. This vehicle was produced from 1970 to 1997. - almost 30 years. For disabled people of Soviet times, this motorized stroller was an indispensable means of transportation, and it was also issued by the state free of charge. A person could use it for 2.5 years, then major repairs were carried out, also free of charge. The repaired SZD motorized wheelchair was returned to the disabled person, and he could ride it for another 2.5 years. It was believed that after 5 years the motor resource was completely consumed, the vehicle had to be returned to the social security authorities. After this, the disabled person was given a new SZD motorized wheelchair. Thanks to this transport, people with injuries to the lower extremities could lead a full life, move wherever they wanted and feel quite comfortable not only in city traffic, but also on dirt country roads. It was essentially an ATV with a body attached. The designers achieved that the legs of a person in a motorized wheelchair could be fully straightened, and the movement could be controlled by hands. For those people whose legs could not bend, transport became a real godsend.
After the Patriotic War, yesterday's legless soldiers, with orders and medals, moved on homemade carts, looking up at people. The opportunity to be on the same level as healthy people was the best means of social rehabilitation.
Why a motorized stroller?
Designers of the Soviet period wanted to create a simple and trouble-free little car for rural residents, but the state allocated funds to support disabled people. The vehicles were supposed to be produced at GAZ, but the plant was overloaded with the production of trucks, and the order was transferred to Serpukhov. The plant there had a much more modest technical base, as a result of which the SZD motorized stroller was significantly simplified and adapted to local capabilities. The result was a compromise between a real passenger car and a good prosthesis: advantages and disadvantages were present in equal measure.
In fairness, it must be said that the parts of the motorized carriage were in great demand, from which other equipment was made in the Kulibin garages: all-terrain vehicles, tiny tractors, snowmobiles, cars of their own design and other models. In the Soviet magazine “Modelist-Konstruktor” people shared their technical solutions on this topic. Boys in the Houses of Pioneers and circles of young technicians enthusiastically made various moving homemade products, the parts for which were the same decommissioned motorized strollers.
From the world by thread
They didn’t invent anything specifically for the motorized stroller, but took something ready-made and modified it. So, the engine of the SZD sidecar is a motorcycle one, from IZH-Planet, rear-wheel drive. The steering is rack and pinion, the suspension on all wheels is independent torsion bar, the body is monocoque, the brakes on all four wheels are hydraulic. The front suspension was “written off” from the Beetle, it was invented by Ferdinand Porsche himself.
The motorcycle engine has become derated. They installed forced air cooling on it, added an additional electric starter, and also installed a Moskvich generator nearby. The fuel tank was located lower than on a motorcycle, and an additional fuel pump was installed, which was used on boats. All this led to the fact that the engine was not afraid of any frost; starting took place in one touch.
The fuel for the engine was a mixture of gasoline and oil in a ratio of 20:1, and people managed to add waste to low-octane gasoline. The motorized carriage still drove, but the service life of the engine was shortened. A 10 horsepower engine consumed 5 liters of fuel per 100 km.
The gearbox is manual 4-speed, there is no reverse gear. Instead of reverse gear, a gearbox or reverse gear was installed, so the stroller could go backwards in any gear. There was also a petrol heater with a separate petrol tank.
Control levers
They are truly unique; a person could do with his hands what everyone else uses 4 limbs for. In addition to the levers we are used to, the SZD wheelchair also had the following:
- Brake lever.
- Reversa.
- Kick starter.
- Clutches.
- Accelerator (gas).
Riding a motorized wheelchair was not very comfortable.
The little car sneezed, rattled, was poorly heated, rattled and could reach a speed of no more than 55 km/h. There could only be one passenger, but still people were protected from snow, bad weather and off-road conditions. The length of the motorized stroller is a little more than 2.5 meters, and the weight is about half a ton. In the unforgettable “Operation Y,” the actor Morgunov easily moves the car, and any person could repeat the same thing. With the light hand of a wonderful actor, the little car received the popular name “Morgunovka”.
Innovative technical solutions
The technical characteristics of the SZD motorized stroller were far ahead of their time. So, each wheel had an independent suspension. This design appeared on Soviet cars only 20 years later. This scheme is better known under the name “MacPherson suspension”, also known as “swinging candle”. Each wheel has a shock absorber strut, so the stroller was not afraid of loose soil, sand, stones, or shallow holes. The motorized stroller was an ideal means of transportation on rough roads and off-road.
The rack and pinion type of steering was also installed for the first time on a motorized stroller. This type gives high rigidity. Simply put, rack and pinion steering makes it easy to turn the wheels in a critical situation, safe and simple. After the end of the turn, the steering wheel automatically returns to its original position, and play never occurs.
The clutch cable drive is another technical simplification. No hydraulic booster or oil is required, just one cable - and the clutch discs are separated, the transmission of torque from the engine to the wheels is stopped.
Electrical diagram
It included 42 elements that provided all the functions necessary for the car. The electrical circuit of the SZD motorized stroller had the following main components:
- Rechargeable battery.
- Generator.
- Headlights and stop lights.
- Relay switches.
- Control lamps.
- Headlights and sidelights.
- Wiper.
- Fuse box.
There was even such a luxury as an engine compartment lamp. There was a control lamp - a neutral position indicator, a plug socket, a fuse box, as well as a ceiling light in the cabin. The instrument panel is a minimalist's dream: speedometer, ammeter and fuel level indicator. The engine could be started either with a key or with a kickstarter lever. At a time when half of the cars started with a “crooked starter” in any weather, the ability to start the engine from the passenger compartment was unprecedentedly comfortable.
Is it possible to buy a stroller today?
A real rarity - that’s what the SZD motorized stroller is called today. Avito, for example, offers options both in Moscow and in other regions of Russia. In the capital, a Morgunovka costs about half a million rubles, however, it has undergone a complete restoration, and it is a collector’s item. Ordinary motorized strollers in varying degrees of preservation, with or without documents, are sold at prices ranging from 6 to 25 thousand rubles.
Today people buy a motorized stroller not so much for utilitarian purposes, but as a materialized memory of a warm, but forever gone time.
I decided to build myself a walk-behind tractor for my household. I already had an engine ideally suited for this task - from an SZD motorized stroller. But I didn’t have a suitable gearbox through which I could increase the overall gear ratio of the transmission and at the same time realize the ability to move in reverse.
So I thought this way and that, and in the end I decided to “dance” from some mass-produced gearbox or, at worst, to adapt a box from a Ural for this purpose. I didn’t have to look for the device I needed for a long time: on occasion, I was given two killed “Maravievsky” gearboxes. One of them “caught a wedge” about twenty years ago and was left in the barn awaiting its finest hour, and the second still showed signs of life, but had serious damage to the body and severe wear of gear teeth and bearings.
After disassembling both copies, it turned out that the support bearing of the input shaft had crumbled in the jammed gearbox. It would be fine, you might say, it’s a common thing, but the whole problem was that during operation, the balls of the scattered bearing got between the gear teeth, which led to their breakage. Everything else, including the housing and internal parts of the differential, to my great joy, remained intact and unharmed. The internal parts of the second gearbox turned out to be in much better condition, but still, years of merciless use left their negative mark on their condition.
At first I wanted to buy the damaged parts from the store. Oddly enough, the spare parts I needed were found in the store - I don’t want to take them. And most importantly, the spare parts were still Soviet-made, coated with a thick layer of grease and wrapped in special paper - not 100% China. But the price for them made me think twice... In general, for two gears and an intermediate shaft, the trader asked me more than two rubles + new bearings, a piece of paronite for a gasket and a set of seals, and absolutely - the price appeared to be three rubles...
I thought about it and decided to limit myself to buying new bearings and seals, and borrow the damaged gears and intermediate shaft from another gearbox. In general, make the gearbox a classic “brute force”, which is exactly what will be discussed in this article.
So, all the parts have been cleaned, washed, checked for acceptable wear and damage, the threads have been run, all that remains is to collect all this junk “to the heap”.
We install the bearings in the gearbox housing preheated with a technical hair dryer. If anyone needs it, here are the bearing numbers:
- 18 GPZ_204_KZ - 2 pcs (input shaft);
- 4_GPZ_60203_K-2pcs (intermediate shaft);
- 4_GPZ_7_207_K_5-2pcs (differential housing);
We lay the right half of the body on planks so that the shafts coming out of the body hang freely in the air and do not interfere with work. We place a standard thrust washer on the support bearing of the input shaft.
We put the gear on the input shaft as shown in the picture and insert it into the housing. Before installing the gears, pay attention to their teeth and jaw couplings that engage the gears with each other. The teeth should not be chipped, damaged, cracked or show signs of excessive wear. The cams must be of the correct shape with sharp, not licked edges.
We put the intermediate shaft in place.
Thoroughly clean and wipe the working surface of the differential axle shaft and the cup into which the axle shaft fits. We put a standard thrust washer on the axle shaft and insert it into the cup. We take a set of measuring probes, select the thinnest one from them and try to insert it between the working surfaces of the differential cup and its axle. If the selected probe passes between the parts without noticeable force, take a thicker probe and repeat the procedure again until the probe enters with noticeable force.
My measuring process was completed on a probe 0.05 mm thick; a thicker probe no longer passed between the parts, which means that the production in this connection does not exceed 0.05 mm. The norm is no more than 0.1 mm. If your measurement procedure ends at 0, 1 mm or more on the probe, replace the axle shaft or cup with a new one.
In the same way, we put the satellites on the axle one by one, while carefully making sure that they stand exactly in the place where they stood before disassembly, that is, in the place where the output will be maximum. And we try to insert a measuring probe between the axle and the inner hole of the satellite. The permissible wear limit, as in the first case, should not exceed 0.1 mm.
We insert the satellite axis into the cup so that it extends slightly beyond the edge and put a thrust washer on it.
We put the satellite on the axle, push the axle further, put on the second satellite, adjust the thrust washer under it and push the axle.
We rotate the axle so that the hole for fixing it coincides with the hole in the cup and secure it from falling out with a locking pin.
We connect the cups to each other, put thrust washers on the outer ends of the axle shafts and secure them with retaining rings. The axle shaft can be fixed immediately after installation in the cup, or it can be fixed later - it doesn’t matter.
We put the gears on the differential housing. There is no particular difference where to put which gear. It will work either way or that way. We put locking plates on the bolts and carefully tighten the body with them. Try to tighten the bolts evenly, crosswise and as tightly as possible; several gearboxes passed through my hands in which the bolts were loosened, which caused both the bolts themselves and the housing to break during operation.
I was born in 1944, and almost from the first year of my life I was haunted by a sound - the ominous growl of bearings rolling on the asphalt. This sound accompanied the movement of legless disabled people returning from the war on small wooden carts...
And there were a lot of them at that time - according to current estimates, over three million. Most of yesterday's medal bearers disappeared into the vast expanses of our country, but many settled in cities, including the capital of our Motherland. And their only vehicle at that time was a cart made of planks on ball bearings, equipped with a pair of rough pieces of wood, reminiscent of irons, with which disabled people, pushing off from the road, set it in motion...
The first motorized three-wheeled wheelchair “Kievlyanin”, made on the basis of a 98 cc motorcycle
with the same name, resembled a two-seater sofa to which the front part of a motorcycle was attached. True, instead of a motorcycle steering wheel, the tricycle driver used a long lever. The speed of such a hybrid, unprotected from the unpredictable external environment, did not exceed 30 km/h.
The next, more comfortable motorized stroller, called S1L, was designed at the Central Design Bureau of Motorcycle Manufacturing. Serial production of this vehicle was launched at the Serpukhov Motorcycle Plant (SMZ). 
A little historical background. SMZ began its activities in 1939. At first, it produced small series of domestic motorcycles such as MLZ and J18, and during the war they organized the repair of German captured motorcycles and the assembly of those that came to the country under Lend-Lease - American Indian and Harley.
The two-seater three-wheeled motorized carriage S1L was strikingly different from the “Kievlyanin” - it had a metal body with a pair of doors and a folding canvas awning that protected the crew from bad weather.
The car body frame was welded from thin-walled pipes, onto which steel panels were hung. Rear suspension - independent, spring, wishbone. Wheels - with tires measuring 4.50 - 9.
The engine is a motorcycle, two-stroke, with a displacement of 125 cm3 and a power of ... 4 liters. With. - this was barely enough to accelerate a car weighing 275 kg to a speed of 30 km/h. And driving a three-wheeled car along a dirt road with two ruts was almost impossible. And the stability of the stroller - especially when cornering - left much to be desired. The lighting was also unimportant - only one 6-volt headlight.
In 1956, the tricycle was modernized - a two-stroke IZH-49 engine with a displacement of 350 cm3 and a power of 7.5 hp was installed on it, which allowed the machine, called SZL, to reach a “crazy” speed of 55 km/h.
In 1957, in the design department of SMZ, together with NAMI, they developed a more modern SZA motorized stroller - it was launched into series in 1958.
The new car was made with four wheels, with tires measuring 5.0 - 10 and with a torsion bar suspension on the front wheels - the same as a Volkswagen car. Elastic suspension elements - plate torsion bars - were located in transversely located cylindrical housings welded to the longitudinal tubular frame spars. The arms of the independent spring suspension of the rear wheels with friction shock absorbers were also attached to them.
The power unit - a two-stroke IZH-49 motorcycle engine coupled with a four-speed gearbox - was located in the rear of the body. The motor was equipped with a forced air cooling system, consisting of a centrifugal fan and a metal casing. The engine was started using an electric starter, but the engine could also be started manually using a starting lever installed in the cabin.
By the way, the SZA two-stroke engine consumed not gasoline, but a fuel mixture consisting of gasoline with an octane rating of 72 and AC-8 oil in a ratio of 20:1, which created additional difficulties - at that time it was not easy to buy gasoline, but getting oil is even more difficult. 
The final drive housing, containing the bevel gear differential and reverse gear, was mounted under the engine. Torque from the engine to the main gear was transmitted by a bushing-roller chain - a transmission of this type provided four gears for both forward and reverse. However, for reversing, drivers, as a rule, used only first gear.
The brake on the motorized stroller was manual, with mechanical drive to the rear wheels.
The curb weight of the stroller was 425 kg, which was too much for a ten-horsepower engine, so the maximum speed of the car was only 60 km/h. Despite the low power, the engine consumed about 5 l/100 km.
When creating a motorized stroller, it was assumed that the cost of specialized wheelchair vehicles, which social security authorities distributed among disabled people free of charge, would be small, but production with a predominance of manual labor, as well as the use of a large number of expensive chromansil pipes for the body frame, made the cost of this vehicle higher than that of Moskvich-407, produced during the same period.
Since 1968, SMZ began producing a modernized motorized stroller, called SZA-M. The car was equipped with a more efficient muffler, hydraulic telescopic shock absorbers, rubber axle joints and other, less significant innovations.
To be fair, it should be noted that the utilitarian motorized stroller SZA contained in its design a number of elements used in our country for the first time - they appeared in the “big” automobile industry only years later. In particular, a rack and pinion gear was used for the first time in the steering system - the next domestic car equipped with this mechanism was the VAZ-2108, launched into production in 1984.
It is worth mentioning the independent rear suspension on trailing arms - at that time almost all passenger cars were equipped with a continuous rear beam, and only the “humpbacked” Zaporozhets ZAZ-965 had an independent suspension.
And, of course, a cable clutch drive, which is now equipped in almost all passenger cars. However, he was forced to appear on a motorized wheelchair, since a motorcycle engine is designed for just such a drive.
The design of the SZA made a very positive impression - a rounded front end, embossed fenders of the front wheels with headlights attached to them - all this created the impression of a miniature but proportionate car in a retro style. However, for some reason in our country they do not like to use the accumulated experience, and they begin to design each new car “from scratch.” This is exactly how the brilliant Pobeda brand went into oblivion, this is how the appearance of Niva disappeared into dozens of foreign SUVs. And just like that, instead of the “warm and fluffy” baby SZD, another SZD wheelchair appeared as if knocked together from boards.
Preparations for the production of a new motorized stroller began in April 1967, and production began in 1970. Designers and production workers intended the release of SZD to get rid of a number of disadvantages inherent in SZA. So, unlike its predecessors, the new car had an all-metal body, but the weight of the car, compared to the SZA, which had a frame-type metal body, did not decrease, but increased by as much as 70 kilograms!
The trunk was tiny - it housed the spare tire and heater, and there was practically no space left for luggage. That is why many owners equipped their motorized strollers with homemade roof racks, which was not provided for by the design of the car.
However, the PPA also had many advantages. Thus, the closed all-metal body, equipped with a very voracious but effective gasoline heater, made it possible to use the motorized stroller at any time of the year. The maximum speed has increased by as much as 5 km/h! Unlike the SZA, not only the rear, but also the front wheels were equipped with brakes, and the brake drive was made hydraulic.
The car's interior, to the surprise of the owners, turned out to be more spacious than its predecessors. The 12-horsepower IZH-P2 engine (later referred to as the 14-horsepower IZH-PZ) accelerated the car to 55 km/h (it should be noted that the motorcycle versions of these engines were more powerful - 15.5 and 18 hp, respectively, well and modifications of engines for motorized wheelchairs were derated to increase their service life).
The carburetor is the K-36E type, quite primitive by today's standards (later it was replaced by the more advanced K-62).
The muffler was welded, non-separable, with a pair of small-diameter exhaust pipes, which looked very funny. The engine cooling system is air, forced. Clutch - motorcycle type: multi-disc, oil bath. The gearbox (as well as the clutch mechanism) was located in the same block with the engine; switching algorithm: moving the lever from neutral forward - first gear; from neutral with successive backward movements - second, third and fourth, respectively. 
The main gear mechanism was a gearbox on spur gears with a gear ratio of 2.08. The differential is assembled from two bevel gears and a pair of satellite gears. The reverse gearbox (reverse gear) is formed by three spur gears with a gear ratio of 1.84.
The electrical equipment of the vehicle was designed for a rated voltage of 12 V, the G-108-M type generator was an automotive type, DC, with a power of 250 W. The electric equipment of the sidecar also included headlights, sidelights, front and rear turn indicator lights, a rear license plate light and a brake light, as well as an electric windshield wiper and a sound signal.
The instrumentation was more than modest - it consisted of a speedometer and an ammeter.
The suspension of both front and rear wheels is independent, torsion bar. Shock absorbers - telescopic, hydraulic, double-acting. Wheels - stamped, disc, collapsible.
The capacity of the fuel tank was 18 liters - when driving at operating speed on the highway, a full refueling was enough for 220 - 260 km.
It is interesting that the SZD motorized stroller was designed only to be controlled using hands - it did not have pedals. The throttle and clutch handles were located on the steering wheel, the brake lever and gearshift lever were installed to the right of the driver. However, a small series with a different arrangement of controls was also produced for drivers with one arm and one leg.
The SZDs were simple and unpretentious in operation. Many drivers serviced and repaired their motorized strollers themselves, which was greatly facilitated by the fact that spare parts for engines could be purchased not only in specialized stores, but also in those that sold parts for engines of IZH-Planet motorcycles.
It should be noted that in the USSR, the creation of disabled vehicles was carried out not only at SMZ, but also at the Zaporozhye Automobile Plant. In particular, ZAZ mass-produced five varieties of the ZAZ-968 car for drivers with various types of disabilities.
As already mentioned, motorized wheelchairs were issued to disabled people by social security authorities free of charge, and after five years they were subject to write-off and replacement with new ones. However, in a number of cities, decommissioned motorized strollers were not disposed of, but were handed over to clubs and stations for young technicians. As it turned out, these mini-cars turned out to be an excellent “constructor” for the technical creativity of young people - if desired, they could be used to assemble buggies of the “zero” class, compact cars of a wide variety of designs - from sedans to convertibles and from minivans to minibuses, as well as snowmobiles of various designs and types. Quite a few of these universal “constructor sets” were “as an exception” given to amateur designers.
Technical characteristics of the SZD motorized stroller
Length, mm - 2825
Width, mm - 1380
Height (without load), mm - 1300
Base, mm - 1700
Track, mm - 1114
Ground clearance, mm - 170-180
Dry weight, kg - 465
Curb weight, kg - 498
Weight with full load, kg - 658
Maximum speed, km/h - 55
Operating fuel consumption, l/100 km - 7 - 8
Fuel tank capacity, l - 18
Engine, type - IZH-P2 (IZH-PZ)
Maximum power, hp - 12(14)
Working volume, cm3 - 346
Fuel - A-72 gasoline mixed with motor oil
Cooling - air, forced
Clutch - multi-disc, oil bath
Front suspension - independent, torsion bar
Rear suspension - independent torsion bar
Brakes - drum, shoe, hydraulically driven
Rated operating voltage, V. - 12
Generator power, W - 250
One of the most stylish cars made on the basis of SZA motorized stroller units was the Ant car, designed by the famous designer of the 1960s - 1970s E. Molchanov and built by Moscow engineer O. Ivchenko. The car at one time received first prize at the all-Union show-competition of amateur designs, and gained national fame after the release of the wonderful film “Racers”, where “Ant” starred as an “actor” together with the brilliant O. Yankovsky and E. Leonov.
IN ideo:
“Ant” from the inside as seen by A.N. (part 1).
The number of teeth of the forward input shaft gear is 22.
The number of teeth of the reverse input shaft gear is 25.
The number of differential gear teeth (forward) is 47.
The number of differential gear teeth (reverse) is 52.
Circumferential module of teeth m (according to Article CMEA 310-76) = 2.5 mm (for all gears of the gearbox).
The circumferential pitch of the teeth along the pitch circle is P = m x PI = 7.854 mm.
Center distances between crankcase axles:
Primary shaft - differential: 96.25+0.25 mm,
Diameters of the circles of the tops of the gear teeth (Da) and the bottoms of the gear teeth (Df):
Forward input shaft: Da = 60 mm, Df = 48.75 mm,
Reverse input shaft: Da = 67.5 mm, Df = 56.25 mm,
Differential gears (forward): Da = 122.5 mm, Df = 111.25 mm,
Differential gears (reverse): Da = 135 mm, Df = 123.75 mm.
Gear ratio (forward) – 2.136; gear ratio (reverse) - 2.080 (roughly speaking, the gearbox reduces the speed (and, accordingly, increases traction) by half).
The input shaft is splined with 6 splines, like the sprocket of the Tula or Ant engine (chain on the wheel).
On the “original” axle shafts, the splined one is the same (the splined cardan of the Ural motorcycle fits on it).
Used gear drive chain sprockets: pitch 15.875 (IZH-SZD) – 21 (there are 12, 10, 9 teeth),
pitch 12.7 (Ant, Minsk) – 11 or more teeth.
Bearings: input shaft - No. 000 (2 pcs), bore in crankcase Ø 47 mm,
differential - No. 000 (2 pcs), boring in the crankcase Ø 72 mm.
Inner diameter of landing holes. for standard axle shafts in the differential box - 25 mm (for reference, the front beam pin of a Gazelle car (its diameter is 25 mm) can be used as a solid shaft for converting the gearbox into a gearbox with a locked differential for installation on a snowmobile for reversing. ). The differential housing is cast iron (a metal that does not respect welding)! For numerous options for switching to a solid shaft, see our forum.
There is no fixed neutral (you can make a groove for it on the fork stem). The slots on the shift shaft are like those on the Tula, Minsk, and Voskhod gearboxes.
It is possible to “mirror” the gearbox (transfer the drive sprocket from right to left to shift the gearbox to the right of the snowmobile axis and reduce the drive shaft console onto the track). Implemented by Radosnego.
It is possible to strengthen the gearbox housing (each half-crankcase is framed with a steel angle frame; in a standard crankcase, breakage of the tides under the mounting studs is a common occurrence). Implemented by Radosnego.
