DOI: 10.5545/sv-jme.2024.1184 199
© The Authors. CC BY 4.0 Int. Licencee: SV-JME  Strojniški vestnik - Journal of Mechanical Engineering   ▪   VOL 71   ▪   NO 5-6   ▪  Y 2025
Geometric Design Method  
of Lightweight Line Gear Mechanism
Chao He
1
 – Yangzhi Chen
1,2
 – Xiaoxiao Ping
1
  – Zhen Chen
1
 – Maoxi Zheng
2,3
 – Qinsong Zhang
2
1 Guangdong Ocean University, School of Mechanical and Energy Engineering, China
2 South China University of Technology, School of Mechanical and Automotive Engineering, China
3 University of Electronic Science and Technology of China Zhongshan Institute, School of Mechanical and Electrical Engineering, China
 xiaoping.xiao@foxmail.com
Abstract Based on the space curve meshing theory, a lightweight line gear mechanism (LLGM) was proposed in this paper. The LLGM can achieve the objective 
of lightweight design by reducing the radial dimension of the gear, which has an improvement in terms of size reduction. The outstanding advantage of the LLGM 
is its ability to achieve a high transmission ratio. Three aspects were proposed to design the LLGM: first, the primary design method was obtained; second, an 
approach to simply and effectively establish the analytical model of the LLGM was presented, which showed that the lightweight characteristic of the LLGM is 
mainly reflected in the radial dimension; third, the discriminant condition of the LLGM was built. The simplicity and effectiveness of the LLGM were demonstrated 
by a design example, while gear contact simulation and kinematics experiments were carried out to verify the theoretical basis. The lightweight design method 
proposed in this paper belonged to structural lightweight design, which can effectively solve the lightweight design issue in gear transmissions characterized by 
light loads and high transmission ratios.
Keywords lightweight design, space curve meshing, gear design, kinematics experiments, high transmission ratio 
Highlights
 ▪ A novel lightweight line gear mechanism (LLGM) was proposed. 
 ▪ The outstanding advantage of the LLGM is the high transmission ratio.
 ▪ The LLGM contributes to material amount savings.
 ▪ Kinematics experiments have been carried out on a homemade test rig.
1 INTRODUCTION
Gear transmission is widely recognized for its high meshing 
efficiency and reliability [1-4]. With the explosive growth of 
electromechanical products, the application of gears has become 
increasingly widespread [5]. Green transmission has emerged as 
a mainstream trend in the development of gears for the future. 
Achieving energy conservation and emission reduction has become 
a critical issue in the gear industry [6]. Among various solutions, 
structural lightweight design of gears has drawn the attention of many 
researchers and engineers [7-9].  Additionally, the miniaturization 
of electromechanical products has imposed higher requirements 
for lightweighting [10,11]. At present, lightweight gears have been 
important components in mini-electromechanical products, such as 
unmanned aerial vehicles and mini-robots [12,13]. 
Designing lightweight gears has been a key research issue for 
decades. In order to achieve the goal of lightweight, many design 
methods have been proposed. Some gears adopt a small module [14], 
others undergo topological optimization [15], and some are designed 
as specific gear devices [16,17]. Among the lightweight approaches, 
the simplest lightweight design method is to reduce the gear modulus 
and the number of teeth [18]. However, the load capacity of the gear 
decreases as the gear modulus decreases [19]. Besides, the teeth 
number of gears is normally not less than 17 to avoid undercut 
[20]. Therefore, the simplest lightweight gear design method is not 
universally effective. On the other hand, there are typically more than 
three gears when the transmission ratio of a gear device is more than 
6 — a factor that obviously increases the difficulty of lightweight 
design due to the number of gears [21,22]. The lightweight gear pairs 
are also restricted by the radial dimension limitation of the two gears, 
that is, the diameter of the driven gear is approximately equal to the 
product of the diameter of the driving gear and the transmission ratio. 
Once the diameter of one gear and the value of the transmission ratio 
are determined, the radial dimension of the other gear cannot be 
reduced. In summary, the previous lightweight designs leave room 
for improvement in terms of size reduction, especially under high 
transmission ratios.
To address the challenge of lightweight, this paper presents a 
lightweight design method based on a new theory. The method 
proposed in this paper belongs to structural design, and it 
can effectively address the challenge of lightweight design in 
mechanical transmissions with low-load and high-transmission-
ratio characteristics. The research foundation of this paper primarily 
relies on the space curve meshing theory [23,24], called line gear 
(LG) [25]. Different from involute gears, LG can realize stable 
meshing transmission through two contact curves. Also, LG has 
the characteristics of a small number of teeth and no undercutting, 
making it suitable for lightweight design.
In this paper, a novel LG, named lightweight line gear mechanism 
(LLGM) is proposed. The LLGM can break through the radial 
dimension limitation of the two gears and achieve the objective of 
lightweight design by directly reducing the radial dimension of 
the gear, thereby achieving better size reduction performance than 
previous lightweight gears and LG. The design of the LLGM was 
proposed from three aspects: first, the primary design method was 
obtained through research; second, a simple approach for establishing 
the LLGM was presented; third, the discriminant condition of the 
LLGM was built. After that, a design example of the LLGM was 
put forward and a comparison was carried out between the LLGM 
and an ordinary LG pair. Gear contact simulation was carried out to 

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200   ▪   SV-JME   ▪   VOL 71   ▪   NO 5-6 ▪   Y 2025
verify the contact characteristics. Finally, kinematics experiments 
were carried out to verify the proposed design theory. The LLGM is 
suitable for mini-electromechanical products, offering a new solution 
in mechanical transmissions characterized by high transmission 
ratios, lightweight design and compact size. 
2 METHODS AND MATERIALS
2.1 Primary Design Parameters of the LLGM
The LLGM is build in accordance to the space curve meshing theory. 
Therefore, the LLGM mainly involves the design of two conjugate 
curves that present cylindrical helices [25], as shown in Fig. 1.
Two cylindrical helices denoted as A and B respectively, are 
rotated around their respective axes. Two fixed coordinate systems 
determine the relative position of curves A and B, and are named 
O
1
 – x
1
y
1
z
1
 and O
2
 – x
2
y
2
z
2
, respectively. The distance between them 
is expressed as a. The parameter equations of curves A and B were 
represented in the coordinate system O
a
 – x
a
y
a
z
a
 and O
b
 – x
b
y
b
z
b
, 
respectively. The O
1
 – x
1
y
1
z
1
 and O
2
 – x
2
y
2
z
2
 coincided with the 
O
a
 – x
a
y
a
z
a
 and O
b
 – x
b
y
b
z
b
 at the initial position. The curve A rotated 
through an angle φ
a
 at a uniform angular velocity ω
a
 and the curve B 
rotated through an angle φ
b
 at a uniform angular velocity ω
b
 while the 
two curves conducted conjugate motion. 
Curves A and B can be expressed as Eqs. (1) and (2) in the 
coordinate system O
a
 – x
a
y
a
z
a
 and O
b
 – x
b
y
b
z
b
, respectively.
R
a
a
a
a
a
a
a
a
xm t
ymt
zn t














M
M
M
cos
sin, (1)
R
b
b
b
b
b
b
b
b
xmt
ymt
zn t














M
M
M
cos
sin, (2)
wherein t is the independent variable, m
a
 and m
b
 represent the helix 
radius, n
a
 and n
b
  represent the pitch parameter.
The transformation matrix between the above coordinate systems 
can be expressed as:
M
21
100
0100
0010
0001













a
, (3)
M
1
00
00
00 10
00 01
a
aa
aa

 











coss in
sinc os
,


 (4)
M
2
00
00
00 10
00 01
b
bb
bb

 











coss in
sinc os
,


 (5)
where M
21
, M
1a
 and M
2b
 represent the transformation relationship 
between the coordinate systems O
1
 – x
1
y
1
z
1 
and O
2
 – x
2
y
2
z
2
, O
1
 – x
1
y
1
z
1
 
and O
a
 – x
a
y
a
z
a
, O
2
 – x
2
y
2
z
2
 and O
b
 – x
b
y
b
z
b
, respectively.
The equation of curve A can also be expressed in the coordinate 
system O
1
 – x
1
y
1
z
1
 by Eq. (6), which defines rotation of curve A 
around the z
1
 axis.
RMR
1
1
1

aa
a
. (6)
The equation of the curve B can be similarly expressed in the 
coordinate system O
2
 – x
2
y
2
z
2
 by Eq. (7), defining rotation of curve B 
around the z
2
 axis.
RMR
2
2
2

bb
b
. (7)
According to the conjugate condition, the curve A is tangent to the 
curve B while they are rotating, which can be expressed as:
RM R
2
2
21 1
1
= . (8)
The two sides of Eq. (8) represented the equations of the curve A 
and B in the coordinate system O
2
 – x
2
y
2
z
2
. The solution to Eq. (8) is 
the position of the contact points of the two curves. 
Further, Eq. (9) is obtained by substituting the known parameters 
into Eq. (8).
coss in
sinc os
cos
sin


bb
bb
b
b
mt
mt
n
 











00
00
00 10
00 01
b b
a
t
a
1
100
0100
0010
0001




























 coss in 
a a
aa
a
a
a
mt
mt
nt
00
00
00 10
00 011
sinc os
cos
sin 












 




 








. (9)
Fig. 1. Primary theory of the LLGM

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Structural Design
At the initial position, φ
a
 and φ
b
 are both equal to 0. At other 
positions, the relationship between φ
a
 and φ
b
 is expressed as Eq. (10) 
by the gear transmission principle.

ab
i  , (10)
where i is the transmission ratio. By substituting the parameter i 
into Eq. (9), Eq. (11) can be obtained according to the space curve 
meshing theory. 
i
n
n
b
a
= . (11)
Equation (11) reveals the main factor influencing the transmission 
ratio of the LLGM, is the pitch ratio of the two curves.
2.2 Lightweight Design Method of the LLGM
Since the transmission ratio of the LLGM is directly related to the 
pitch ratio according to Eq. (11), the lightweight design of the LLGM 
can be mainly reflected in the radial dimension. A simple approach 
to establish the LLGM model was proposed for analysis, as shown 
in Fig. 2.
In Figure 2, the LG tooth was generated by sweeping, where the 
cylindrical helix was used as the path and the tooth profile was as 
used as the profile. There were two gear pairs, one was the ordinary 
LG and the other was the LLGM. As Figure 2 shows, both of the 
two gear pairs have the same driving gear, but the driven gear of 
the LLGM is smaller than that of the ordinary LG, while they have 
the same transmission ratio. In other words, the LLGM can achieve 
lightweight design by reducing the radial dimension.
2.3 Lightweight Condition of the LLGM
2.3.1 The Discriminant Condition of the LLGM
It can be seen from Fig. 2 that the LLGM and the ordinary LG 
have a similar structure. Therefore, it is necessary to introduce the 
discriminant condition of the LLGM. The main difference between 
the LLGM and the ordinary LG is the radial dimension. The change 
of the radial size brings a different sliding rate simultaneously. 
Therefore, the lightweight condition of the LLGM can be illustrated 
in terms of the sliding rate. According to the design theory of LG 
[26], the sliding rate can be calculated by Eq. (12).
S
nm
in m
r
bb
aa



1
22
22
, (12)
where S
r
 represents the sliding rate. For the ordinary LG, the 
parameter m
b
 is approximately equal to im
a
 [26]. The relationship 
between the parameters n
a
 and n
b
 can be expressed as Eq. (11). 
Therefore, the sliding rate of the ordinary LG can be derived from 
Eq. (12).
S
ro
≈ 0. (13)
For the LLGM, the parameter m
b
 is smaller than im
a 
and the 
parameter n
b
 is equal to in
a
. Therefore, nm
bb
22
+ is smaller than
in m
aa
22
+
, and the sliding rate of the LLGM can be expressed as 
the inequality:
S
rl
> 0, (14)
where S
rl
 is the sliding rate of the LLGM. As shown in Eq. (13) and 
inequality in Eq. (14), the sliding rates of the LLGM and the ordinary 
LG are different. In short, the discriminant condition of the LLGM 
can be derived as follows.
1. m
b
 < im
a
;
2. S
r
 > 0.
2.3.2 Degree of Lightweight of the LLGM
The degree of lightweight of the LLGM can be described by 
comparing the radial sizes of the LLGM and the ordinary LG. The 
degree of lightweight of the LLGM can be expressed as:
L
im m
mi m
i
ab
aa









100 %, (15)
The larger L
i
, the greater the degree of lightweight. According to 
Eq. (12), the sliding rate increases with the degree of lightweight. 
Generally, the degree of lightweight of the LLGM is limited by 
sliding speed, which can be calculated by:
S
n
nm
nm
i
va a
bb
 










r
30
22
22
, (16)
where S
v
 is the sliding speed of the LLGM, and n
r
 is the rotating 
speed of the driving wheel. The sliding speed can be selected 
according to the lubrication conditions [27]. Also, Eqs. (15) and (16) 
Fig. 2. Lightweight schematic of the LLGM

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202   ▪   SV-JME   ▪   VOL 71   ▪   NO 5-6 ▪   Y 2025
demonstrate that the LLGM maintains a sliding ratio greater than 0, 
with the sliding rate increasing as the degree of lightweight increases. 
In contrast, the sliding rate of LG gears remains constant and 
theoretically approaches zero, while the sliding rate of involute gears 
continuously varies throughout the meshing process and reverses 
direction at the pitch point. In short, the basic design method of the 
LLGM can be derived as follows:
1. Provide the conjugate curves according to the lightweight 
requirements;
2. Design the two gears;
3. Check the sliding speed.
2.4 Experimental
2.4.1 Design Example of the LLGM
An example of the LLGM was proposed to show the basic design 
method of the LLGM directly. For comparison, an ordinary LG pair 
was also proposed. The transmission ratios of the two gear pairs were 
both set to 8. The equations of the driving contact curves were set the 
same:
R
a
a
a
a
a
xt
yt
zt














M
M
M
10
10
12 7
cos
sin
.
, (17)
where R
a
a
 represents the equation of the driving contact curves. In 
this example, to achieve over 50 % lightweighting, the equations of 
the contact curves for the driven gears are as follows:
R
b
b
b
b
b
xt
yt
zt














M
M
M
27 5
27 5
.c os
.s in ,
101.6
 (18)
R
c
c
c
c
c
xt
yt
zt














M
M
M
80
80
101 6
cos
sin
.
, (19)
where R
b
b
 represents the equation of the contact curves on the driven 
gear of the LLGM and R
c
c
 represents the equation of the contact 
curves on the ordinary driven LG. 
Next, the tooth profile was set as a rounded equilateral triangle 
with a height of 2.5 mm and a fillet diameter of 1 mm; the tooth 
width was set to 40 mm; the tooth numbers of the ordinary LG pair 
were set to 4 (driving gear) and 32 (driven gear), while those of the 
LLGM were set to 2 (driving gear) and 16 (driven gear), respectively. 
The geometry of the LG resembles that of a worm, and among its 
parameters, the pitch parameter is the most critical. Specifically, the 
pitch values of the driving LG and the driven LG were set to 40 mm 
and 320 mm, respectively. 
The 3D models of the two gear pairs can be obtained according to 
the above settings. The main difference between the two gear pairs 
lies in the two driven gears, as shown in Fig. 3.
The comparison between the ordinary LG pair and the LLGM was 
conducted, some comparative parameters were tabulated as shown in 
Table 1.
Table 1. Comparisons between different gear pairs
Comparative items The ordinary LG pair The LLGM
Transmission ratio 8 8
Number of gears 2 2
Material amount [cm
3
] 681 120
Fig. 3. Model of the design example
Fig. 4. The three reducers
According to Eq. (15), the degree of lightweight of the LLGM 
design example was equal to 58.33 %. As shown in Table 1, the 
LLGM achieves significant lightweighting, saving 82.37 % material 
usage compared with the ordinary LG.
2.4.2 Testing of the LLGM Reducer
For the convenience of analysis, an involute gear pair was also 
proposed. The modulus of the involute gear was set to 2 mm since 
the LG tooth size was equivalent to 2 mm modulus. For the involute 
gear, the tooth width was set to 40 mm; the tooth numbers were set 
to 10 (driving gear) and 80 (driven gear). The three reducers were 
designed on the basis of the above settings and then manufactured by 
3D printing technology, as shown in Fig. 4.
The three reducers (LLGM reducer, LG reducer and involute 
gear reducer) were successively installed on a homemade test rig for 
kinematics experiments, as shown in Fig. 5.
Subsequently, kinematics experiments were carried out to test 
the performance of the three reducers on the homemade test rig, 
following the experimental methodology detailed in [28]. During the 
testing, the servo motor provided rotational speed to the reducer while 
the magnetic brake applied the load. The speed data were collected 
by the two encoders fixed on the input and output shafts, respectively. 

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Structural Design
The input speed was set to 750 r/min, the sampling frequency of the 
encoder was set to 10 Hz, and the load was set to 1 N·m.
3 RESULTS AND DISCUSSION
The experimental results were obtained after conducting the tests 
with the given experimental parameters. The transmission ratio data 
was obtained from the collected speed data. The transmission ratio 
diagram was drawn after using the six-point median filtering in data 
processing [25], as shown in Fig. 6. Then, according to the collected 
transmission ratio data, the error analysis was carried out, as shown 
in Table 2. Furthermore, simulation analysis was carried out for the 
three gear drives in ANSYS software, and the tooth surface contact 
stress results were shown in Fig. 7.
Fig. 6. Transmission ratio diagram of the three reducers
Table 2. Some transmission ratio errors of the three reducers
Comparative items LLGM reducer LG reducer Involute gear reducer
Average transmission ratio 8.006 7.988 8.031
Standard deviation 0.192 0.423 0.340
Range error 0.903 1.811 1.970
According to the simulation results in Fig. 7, both the LLGM 
and LG exhibit point contact, while involute gears feature line 
contact. The contact points of the LLGM are distributed along the 
tooth direction position parallel to the axis, and the trajectory of the 
meshing points is consistent with that shown in Fig. 2.
The main experimental results (Fig. 6 and Table 2) indicate that the 
three reducers exhibit similar transmission ratio errors, demonstrating 
comparable kinematic performance. The results also show that the 
LLGM can realize stable transmission with a high transmission ratio, 
which explains the correctness of the geometric design method of 
the LLGM directly. During the testing, the input speed was given 
based on the rated speed of the motor. According to the Eq. (16), 
the sliding speed of the LLGM reducer was calculated as 0.314 n
r
, 
which can inform speed limitations or lubrication design. However, 
there were considerable transmission errors during the testing mainly 
due to manufacturing error. These errors could be mitigated through 
improved manufacturing precision. According to the simulation 
results, the contact stress of the LLGM is greater than that of the 
other two gears, which is unfavorable for its load bearing capacity. 
There are two key factors accounting for the relatively high contact 
stress. One is the presence of point contact, and the other is the lack 
of tooth profile optimization in the LLGM design. Despite using a 
simple tooth profile, we proved the geometric feasibility of its design. 
The simplicity and effectiveness of the LLGM were demonstrated by 
kinematics experiments and simulation analysis.
Furthermore, floor cleaning robot gearbox composed of four-
stage involute gear pairs was used for comparison with the LLGM 
reducer, as shown in Fig. 8. The main comparisons between the 
LLGM reducer and the floor cleaning robot gearbox were shown in 
Table 3. As shown in Table 3, the LLGM reducer achieves a 48% 
volume reduction and a 50 % reduction in the number of gears 
compared with the floor cleaning robot gearbox. Overall, the LLGM 
demonstrates significant advantages in lightweight design and high 
transmission ratio capability, which are especially suitable for small-
scale electromechanical products.
Table 3. Comparisons between the LLGM reducer and the floor cleaning robot gearbox
Comparative items The LLGM reducer The floor cleaning robot gearbox
Modulus [mm] 0.5 0.5
Transmission ratio 64 62.24
Number of gears 4 8
Overall size [mm] 43 × 28 ×21 85 × 36 ×16
Fig. 5. Testing for the three reducers

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204   ▪   SV-JME   ▪   VOL 71   ▪   NO 5-6 ▪   Y 2025
4 CONCLUSIONS
In this paper, a lightweight line gear mechanism (LLGM) was 
proposed, and the main work is summarized as follows:
1.  Based on the theory of space curve meshing, the geometric design 
method of the LLGM was studied, while the lightweight objective 
was achieved by directly reducing the radial dimensions of gears. 
2. An approach to establish a simple and effective analytical model 
of the LLGM was presented. The outstanding advantage of the 
mechanism is its ability to obtain a high transmission ratio in a 
compact size.
3. An LLGM example was given, and experimental tests were 
conducted. The results proved that the LLGM reducer can achieve 
as stable transmission as other gear transmissions under light 
loads.
It has been verified that the geometric design method of the LLGM 
is correct and that the methodology can provide new solutions for the 
lightweight design mechanical transmissions. However, numerous 
challenges remain; such as torque measurement, lubrication 
optimization, strength characterization, dynamic response analysis, 
and precision manufacturing requirement. We aim to carry out more 
in-depth studies in the future to solve these problems.
Fig. 7. Simulation analysis of tooth surface contact conditions
Fig. 8. The floor cleaning robot gearbox

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Structural Design
Nomenclature
O
1
 – x
1
y
1
z
1
   Reference coordinate system for driving gear
O
2
 – x
2
y
2
z
2
   Reference coordinate system for driven gear
O
a
 – x
a
y
a
z
a
   Body coordinate system of driving gear
O
b
 – x
b
y
b
z
b
   Body coordinate system of driven gear
ω
a
  Uniform angular velocity of driving gear, [rad /s]
ω
b
  Uniform angular velocity of driven gear, [rad /s]
m
a
  Helix radius of driving space curve, [mm]
m
b
  Helix radius of driven space curve, [mm]
n
a
  Parameters related to driving space curve pitch, [mm]
n
b
  Parameters related to driven space curve pitch, [mm]
i  Transmission ratio
n
r
  Rotating speed, [r/min]
t  Independent variable
φ
a
  Rotation angle of driving gear, [rad]
φ
b
  Rotation angle of driven gear, [rad]
M
21
 Transformation matrix between O
2
 – x
2
y
2
z
2
 and O
1
 – x
1
y
1
z
1
M
1a
 Transformation matrix between O
1
 – x
1
y
1
z
1
 and O
a
 – x
a
y
a
z
a
M
2a
 Transformation matrix between O
2
 – x
2
y
2
z
2
 and O
b
 – x
b
y
b
z
b
R
a
a
 Equation of driving space curve in O
a
 – x
a
y
a
z
a
R
b
b
 Equation of driven space curve in O
b
 – x
b
y
b
z
b
R
1
1
  Equation of driving space curve in O
1
 – x
1
y
1
z
1
R
2
2
 Equation of driven space curve in O
2
 – x
2
y
2
z
2
S
ro 
 Sliding rate of the ordinary LG
S
r
  Sliding rate
S
rl
  Sliding rate of the LLGM
L
i
  Degree of lightweight
S
v
  Sliding speed, [m/s]
R
c
  Equation of driven space curve for ordinary  LG
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Acknowledgements This research was supported by program for Zhanjiang 
Science and Technology Plan Project (No.2024B01054 and 2024B01042); 
and scientific research start-up funds of Guangdong Ocean University (Grant 
No. YJR23010, YJR23002, YJR22016, and YJR24019); National Natural 
Science Foundation of China (Grant No. 52275073 and 52405056); and 
Open Fund of Guangdong Provincial Key Laboratory of Precision Gear 
Flexible Manufacturing Equipment Technology Enterprises, Zhongshan 
MLTOR Numerical Control Technology Co., LTD & South China University of 
Technology (No. 2021B1212050012-08).
Received: 2024-10-04, revised: 2025-03-15, accepted: 2025-04-10 as 
Original Scientific Paper
Data Availability The data supporting the findings of this study are included 
in the article.

Structural Design 
206   ▪   SV-JME   ▪   VOL 71   ▪   NO 5-6 ▪   Y 2025
Author Contribution Chao He: Methodology, Formal Aanalysis, Validation, 
Writing – original draft. Yangzhi Chen: Conceptualization, Supervision. 
Xiaoxiao Ping: Conceptualization, Methodology, Resources, Formal Analysis. 
Zhen Chen: Writing – review & editing, Supervision. Qinsong Zhang: Formal 
analysis, Investigation, Writing – review & editing.
Geometrijska metoda zasnove lahkega  
linijskega zobniškega mehanizma
Povzetek   N a  o sno vi  t eo rije  o zo bljenja  pr o s t o r skih  krivulj  je  v  t em  člank u 
preds ta vljen  lahek  linijski  zo bniški  mehanizem  (LLZM).  LLZM  o mo go ča 
dosego lahke konstrukcije z neposrednim zmanjšanjem radialne mere 
zobnika, kar zagotavlja pomembno izboljšavo glede zmanjšanja velikosti. 
Posebna  predno s t  LLZM  je  mo žno s t  do seganja  viso kih  preno snih  razmerij.  Za 
zasno v o   LLZM  so  bili  predlagani  trije  vidiki:  pr vič,  do lo čena  je  bila  o sno vna 
me t o da  zasno v e;  drugič,  preds ta vljena  je  bila  eno s ta vna  in  učink o vita  me t o da 
vzpo s ta vitv e  anal itičnega  mo dela  LLZM,  ki  je  po k azala,  da  se  lahk a  zasno v a 
LLZM  o draža  predvsem  v  zmanjšanju  radialnih  mer;  tre tjič,  po s ta vljen  je  bil 
krit erij  za  preso jo   us treznos ti  LLZM.  Prepr o s t o s t  in  učink o vit o s t  LLZM  s ta 
bila prikazana s konkretnim primerom zasnove ter preverjena s simulacijo 
zo bnišk ega  s tik a  in  kinematičnimi  po sk usi,  ki  po trjujejo   t eo re tične  o sno v e. 
Me t o da  zasno v e,  preds ta vljena  v  t em  člank u,  spada  med  s trukturne  me t o de 
lahk e  zasno v e  in  učink o vit o   rešuje  pr o blem  lahkih  zo bniških  preno so v ,  ki 
prenašajo majhne obremenitve in zagotavljajo visoka prenosna razmerja.
Ključne besede lahka zasnova, ozobljenje prostorske krivulje, zasnova 
zo bnik o v , kinematični po sk usi, viso k o  preno sno razmerje