Research and
Development of Machining Methods and Machine Tools
In 1934, the production of transmission prototypes was
started and gear fabrication commenced. However, the gear shape was unclear,
and it was not known which cutting tools should be used for the gear finishing
machine. Kiichiro Toyoda consulted his friend, Professor Shiro Nukiyama of
Tohoku Imperial University, who introduced him to an expert on gears at the
university, Dr. Masao Naruse. Also, arrangements were made for Jiro Iwaoka1 and
Tatsuji Wakamatsu to transfer to the university for study purposes in November
1934.
The two students attended lectures by Dr. Naruse on gear
theory and then brought along Chevrolet transmission gears for analysis. Using
machinery plant microscopes equipped with measuring apparatus, they measured
the gear tooth form precisely in units of 1/100 millimeter. Based on that data,
they drew gear tooth curves enlarged 10 times3 and, using the theoretical
formulae established by Dr. Naruse, they determined the gear geometry and
ordered a cutter. This was the first time Dr. Naruse's theories had been put to
practical use.
In the first half of 1934, imported machine tools were set
up in the automobile prototype plant and used as reference materials by Toyoda
Automatic Loom Works and, in 1935, the in-house production of machine tools
commenced. Subsequently, to allow for the full-scale production of machine
tools and jigs for automobile mass production, in May 1937 an Automotive
Department Machining Plant was established within Toyoda Automatic Loom Works.
At the time, the majority of Japanese produced machine tools
were of the full-universal type suitable for various sorts of processes and
used in many kinds of small-lot production. For that reason, they were even
equipped to carry out functions in specialized tasks not needed for automotive
mass production. As a result, imported machines were used as reference
materials in designing and producing machine tools and specialized machines in
the Machining Plant that were limited to the required functions in automotive
mass production. For example, the type A lathe produced in the Machining Plant,
with its simple construction and reliable and light maneuverability, was
highly-regarded. Similarly, the distinctive features of the type C lathe were
its simplification of the mechanisms surplus to lathes used for the production,
and a design emphasizing maneuverability.
Toyota Motor Co.,
Ltd. Model E lathe
These lathes were provided to Toyota Motor Co., Ltd.'s
Machining Plant and its successor, Toyota Machine Works, Ltd., and the type A
lathe was also the first in a series comprised of types A, B, C, D (DD), E, F
and G lathes. Among these, the type E lathe was a production lathe designed and
manufactured in the Toyota Motor Co., Ltd. Machining Plant, with the simplest
type of construction and streamlined mechanisms emphasizing maneuverability.
Since it was rated highly for its quiet turning in the cutting finish and its
machining accuracy and, and its cost was comparatively low, Toyoda Machine
Works increased its production of these lathes to 10 per month.
The Toyota Motor Co., Ltd. Koromo Plant Machining Plant was
completed in November 1938, and the design and manufacturing of machine tools
from within Toyoda Automatic Loom Works was transferred to that plant.
Subsequently, a variety of machine tools, including the ordinary lathes
referred to above as well as multi-spindle drilling machines, automatic
multicut lathes, fine-boring machines, and machine tools specifically for
automotive manufacturing, were produced at the plant.
On May 1, 1941, based on the Machines Manufacturing
Industries Law, the Machining Plant was spun off from Toyota Motor Co., Ltd.,
and Toyoda Machine Works, Ltd. was established. After its establishment, in
accordance with the national policy, production of machine tools for
automobiles decreased, and emphasis was placed on machine tools for aircraft
engine production.
Electrical Components
Research and Development
At first, imported products were used for the electrical
components in the Model GA truck and the Model AA passenger car produced by
Toyoda Automatic Loom Works Automotive Department.1 Kiichiro Toyoda explained
the reason for this as follows:
For a while, we used imported products because, in order to
examine the good and bad points of our products, we had no choice but to employ
items with which we were familiar, rather than adopting new things at that
time. For example, we used foreign products for components such as carburetors,
plugs and oil brakes.... For the time being, how good Toyota's cars could be
was unclear. However, once our automobiles left Toyota, we had to take full
responsibility for any faults. Not being able to escape responsibility for
faults in our own produced parts of the automobile by blaming other parts of
the vehicle was the most important thing for gaining self-confidence in our
products.
Investigation and research into electrical components was
commenced under the direction of Kiichiro when the Model G1 truck was launched
at the end of 1935.3 The electrical engineers researching motors for spinning
frames in the spinning and weaving design department started by analyzing and
sketching the Delco Remy products used in the A engine for the Model G1 truck,
including generators, starters, distributors and ignition coils. At the time,
the production of electrical components in Japan was quite advanced. Nevertheless,
Kiichiro decided that there would be in-house development of electrical
components because he thought that it would be better for the company to obtain
and develop its own electrical technology through independent efforts.
Based on the drawings made in the spinning and weaving
design department, production of prototype electrical components commenced in a
corner of the research plant and the first prototype generators were completed
in October 1936. Around that time, in September 1936, Toyoda Automatic Loom
Works was designated as a licensed company under the Automotive Manufacturing
Industries Law, and was required to use Japanese product components after 1938.
For that reason, the in-house development of electrical components was
expedited but, as it was considered that such efforts would not be sufficient,
orders were also placed with a specialized manufacturing company.
A Hitachi electrical
component for Toyota automobiles
In pursuing this course, after experimenting with samples
from six electronics manufacturers5, it was decided to place orders with
Hitachi Works, Ltd. Electrical components produced by Hitachi6 were similar to
the Delco Remy products in the drawings made by Toyoda Automatic Loom Works,
with dimensions were almost the same, apart from a small degree of error
arising from the conversion from inches to millimeters.
In November 1936, a 600 square-meter electrical components
plant was completed on the west side of the engine plant7, and trial production
was commenced in January the following year. Procuring materials was a problem
in the manufacturing of the prototypes. It was very hard to find manufacturers
that would accept orders for small quantities of special-sized electrical wires
and Bakelite (phenol resin) molded components. Also, distributor condensers
were produced in Japan but, as there was no locally-made condenser paper,
imported products were used. Insulation layer paper for ignition coils was
manufactured from Japanese paper soaked with insulating varnish, and enameled
wire insulating varnish for secondary coils was developed using special quick
heat-drying varnish made with tung oil to avoid wire breakage and insulation
failure.
The prototype products were installed in engines in the
neighboring engine plant and trial running tests took place. However, various
malfunctions occurred. These included a generator flying apart due to an output
shortage and the centrifugal force of the commutator, damage to starter gears,
shafts, springs and other components, ignition coil burnout and wire breakage,
and a defective distributor advance. Despite repeated failures, improvements
continued, and by around July 1937 the company was able to produce electrical
components that could be utilized.
In November 1938, Toyota Motor Co., Ltd. was relocated to
the Koromo Plant, and the electrical components plant was moved to the Kariya
Plant, which was previously the automobile assembly plant. The components plant
then operated at that location together with the remaining truck body plant and
the radiator plant that had been transferred from the Tokyo Shibaura Plant. As
the copper, brass and solder materials used in radiators were common to
electrical components, the electrical components plant was also put in charge
of producing radiators.
In February 1943, preparations began for the transfer of the
electrical components plant to the Kariya-kita Plant (the Kariya components
plant)10 which was leased from Chuo Spinning Company. However, circumstances
completely transformed, and Toyota Motor Co., Ltd., which had been proceeding
with preparations for producing air-cooled aircraft engines at the Koromo Plant
since the start of the year, started to produce them at the Kariya Plant. After
that decision was made, the radiator plant was transferred from the Kariya
Plant to the Koromo Plant in September 1943 and, in October, the machine tools
for aircraft engine production were all brought from the Koromo Plant to the
Kariya Plant. Finally, the electrical components plant was transferred to Chuo
Spinning's Kariya-minami Plant11 in November of that year.
After the war, in October 1946, Toyota Motor Co., Ltd.
created the Spinning and Weaving Department, and resumed spinning and weaving
operations at the Kariya-minami Plant. Later, following an examination of the
splitting off of the Spinning and Weaving Department, the electrical components
plant was moved from the Kariya-minami Plant to the Kariya-kita Plant in
October 1948. At the same time, the radiator plant was transferred from the
Koromo Plant to the Kariya-kita Plant, and both plants were together renamed
the Electrical Components Plant. The Electrical Components Plant was then spun
off from Toyota Motor Co., Ltd. on December 16, 1949, and Nippondenso Co., Ltd.
(currently Denso Corporation) was established.
Source: TOYOTA MOTOR CORPORATION
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