medium and low speed (2m/s) governor of core safety rope...

Medium and Low Speed (2m/s) Governor of Core Safety

Rope of 6mm Diameter Development of MRL Type

Elevators

Jong Seok Lee1, Bo Sung Kim1, Chi Min Tak1, Guem Yong Cho1, Byoung Jo

Jung2*

1 Technology Research Center of SeoKwang Inc., 191, Ilbansaneop-gil, Namsang-myeon,

Geochang-gun, Gyeongsangnam-do, Korea, [email protected] 2* Dept.of Lift Engineering, Korea Lift College., 120, Unjeong 1-gil, Geochang-eup,

Geochang-gun, Gyeongsangnam-do, Korea, [email protected]

Abstract. MRL (Machine Room Less) type elevator use “Compact” gearless

traction hoist machines that typically are mounted within the confines of the

hoistway above the top floor served. MRL type elevator is that the drive sheave

is connected directly to the motor shaft without worm gear. As a result, MRL

type elevator is provide superior ride quality. However, there is a disadvantage

that the capacitance is low. Therefore, previous overspeed governor is suitable

for the elevator of a format that is machine room type elevator. If you want to

use MRL type elevator, it is inefficient. Because of previous overspeed

governor’s size is large and heavy and also, it is very difficult and dangerous to

recover the original states when achieved by the governor machine is the

tripping unless recover by remote control due to which mounted in top of the

hoistway. Therefore, it needs to develop a compacted overspeed governor

suitable for MRL type elevator. In this paper, the structural design of the

governor for development, was strength evaluation.

Keywords: Elevator, Governor, MRL (Machine Room Less), Compact,

Overspeed

1 Introduction

An elevator is a convenient form of transportation for multistory building in modern

society. An elevator is defined as a permanent lifting equipment serving two or more

landing levels, including a car for transportation of passengers and/or other loads,

running at least partially between rigid guide rails, vertical or inclined to the vertical

by less than 15 °. However, frequent use has a high performing and incidence, lead to

a major accident if that happens once accident. In recent years, a situation that

importance has been emphasized for safety. So, modern elevators, electrical safety

devices and mechanical devices are provided. Elevator is constituted by a safety

device, such as overspeed governor, door locking device, a buffer and safety gear etc

[1-4].

A study relates to overspeed governor in such a safety device. Currently, the

elevator of demand there is machine room less traction to an increase in the elevator

of technology development and low-rise buildings is increasing. But, nevertheless, it

Advanced Science and Technology Letters Vol.140 (GST 2016), pp.72-78

http://dx.doi.org/10.14257/astl.2016.140.15

ISSN: 2287-1233 ASTL Copyright © 2016 SERSC

is one of the safety device overspeed governor is using the old one. MRL type

elevator use “compact” gearless traction hoist machines that typically are mounted

within the confines of the hoistway above the top floor served. MRL type elevator is

that the drive sheave is connected directly to the motor shaft without worm gear. As a

result, MRL type elevator is provide superior ride quality. However, there is a

disadvantage that the capacitance is low. Therefore, previous overspeed governor is

suitable for the elevator of a format that is machine room type elevator. If you want to

use MRL type elevator, it is inefficient. Because of previous overspeed governor’s

size is large and heavy.

The diameter of overspeed governor pulley defines to a more than three times the

diameter of the wire rope used for the overspeed governor. Previous overspeed

governor used a wire rope diameter of 8 mm.

Therefore, it needs to develop a compacted overspeed governor suitable for MRL

type elevator. In this paper, the structural design of the governor for development was

strength evaluation.

2 Design of the Study Model

2.1 Design Theory

Overspeed governor is one of the safety control unit of elevator safety protection

system. When the elevator in running no matter what the speed limit in the capsules,

and even the risk of falling, while the other under the condition of safety protection

devices do not work, the speed limiter and safety forceps of upward in linkage

protection device, make the elevator car to stop, governor general inside the elevator

machine room, but also can directly installed in the hoistway beam, machine roomless

speed limiter will be installed on the guide rail or bottom side. A schematic

arrangement of the overspeed governor system is shown in figure 1.

The governor is provided with the governor rope, passing round the governor

pulley, down to a tensioning pulley in the pit and back again to the governor pulley.

The system is driven by the car to which the governor rope is attached at the catch

lever. When the tripping speed of the governor rope is achieved, the governor stops

the rope. Since the car continues in a downward motion, the tension in the governor

rope is increased, exceeding the value necessary to engage the safety gear and,

consequently, the safety gear is set in operation. In compliance with EN81-1, the

tripping speed of the governor for car safety gear should be at least 115 % of the rated

speed and less than [5-8].

(a) 0.8 m/s for instantaneous safety gears except for the captive roller type.

(b) 1.0 m/s for safety gears of the captive roller type,

(c) 1.5 m/s for instantaneous safety gears with buffered effect or progressive

safety gear used for rated speeds ≤ 1.0 m/s

Advanced Science and Technology Letters Vol.140 (GST 2016)

Copyright © 2016 SERSC 73

(d) 1.25𝑣 + (0.25/𝑣), where 𝑣 is rated speed(m/s), for other types of safety

gears.

Fig. 1. Arrangement of overspeed governor system

2.2 Design Conditions

Compact were designed to match the overspeed governor and the tension pulley rated

speed 2 m/s, in order to design, using the Auto CAD 2013 and the Inventor 2014.

Design characteristics of the overspeed governor is as table 1.

Fig. 2. Design for optimization


74 Copyright © 2016 SERSC

Table 1. Design parameter

specification

Rated speed 2 m/s

Speed limit wire rope Ø 6

Diameter of sheave 200 mm (30 times of wire rope’s Dia.)

1st overspeed switch ≤ 2.3 m/s

2nd catch ≤ 2.5 m/s

Tensile force ≥ 60 kgf

3 Finite Element Analysis

3.1 Analysis Conditions

It was subjected to structural analysis for verification of the design. Design same 3D

modeling and design, in order to increase to reliability, and optimize the model by

omitting unnecessary component. It this paper, we complete the finite element

analysis using ANSYS V14 program, a material property values that were used are

follows.

Table 2. Material properties of the overspeed governor

Parts Material Density

(kg/m3)

Poisson’s

Ratio (ν)

Young’s

Modulus

(GPa)

Tensile

strength

(MPa)

Bearing SCR415 7,850 0.30 210 735

Sheave GCD450 7,150 0.28 200 440

Shaft SCM435 7,700 0.30 210 1,158

Case SS41 7,850 0.29 200 415

Wire rope Default 7,850 0.30 200 250



Fig. 3. FEM model(upper) and Boundary condition(below) of overspeed governor

The upper part of figure 3 is a hexa dominant method applied to determine the

exact solution of the structure in mesh option and a size 0.01 mm. The lower portion

of figure 3 shows the boundary conditions for the structural analysis. It gave restraint

by applying a fixed support option to the case bottom.

Load conditions of the overspeed governor, you need to consider the load of the

sheave for the impact of the shoe. Impact load by corresponding to about twice the

static load was applied a load corresponding to the condition extremes to 1,500 N

from the strap end surface of the wire rope in the direction of gravity.

3.2 Results of Analysis

Fig. 4. Result of deformation Fig. 5. Result of stress



Fig. 6. Result of stain Fig. 7. Result of Safety factor

Analysis a result, in the case of the whole of the deformation, appear in the part

of the displacement the wire rope of 0.00017 mm by its own weight and the load, the

deformation of the governor sheave was found to be extremely small. Strain is a

maximum 0.00059 mm.

For the stress, the maximum stress of 1.0743*10-2 MPa at the interface of the

overspeed governor sheave and the rope from the pulling force is generated by the

load conditions of the own weight direction.

Analysis results of the safety factor, the safety factor, shows the results of at least

8.3

This was verified to be a design that ensures the integrity of the structure by a

numerical value that satisfies the safety factor of 8 or more to present safety standards

controversial.

4 Conclusions

In this study, progress in a compact design for medium and low speed (2 m/s) core

safety rope for governor of 6 mm diameter development of MRL type elevators was

subjected to structural strength analysis for the design study.

Conclusions studies are as follows;

1) Designed governor has been compacted designed to meet the elevator safety

standards. Therefore, space utilization rate of the building is increased, the

price reduction is expected.

2) Design of the overspeed governor has been designed in compacted

structures were applied wire rope for 6 mm. So, there is suitable for MRL

type elevator

3) Analysis a results, for the design verification; the whole of the deformation

Max. 0.00017 mm, Strain max. 0.00059 mm, Stress Max. 1.0743*10-2 MPa,

appeared on the safety factor 8, and this satisfies the safety standards of the

elevator.



Acknowledgments. It was supported by granted financial resource from the base

organization support business of creative industries for upgrading of industrial

structure & technology of elevator. Republic of Korea (No. A010800024).

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