Second, no-room elevator technology development
1. Main parameters of some elevator manufacturers MRL elevators
Here are some of the main parameters of elevator manufacturers MRL elevators, see Table 1.

2, MRL elevator drive
From the perspective of the drive system, in addition to the hydraulic drive mode, MRL elevators have the following options.
(1) AC induction linear motor drive. The traditional rotary electric machine becomes a linear motor when its diameter is infinite. Using a linear motor to drive the elevator up and down, unlike the traditional elevator drive, the rotary motion of the traction machine is converted into the linear motion of the car, thereby saving the engine room. This facilitates the aesthetic design of the building's exterior appearance and takes up less of the hoistway area. However, with the linear motor drive, the biggest disadvantage is that a long primary/secondary winding needs to be installed in the elevator shaft, making it difficult to ensure even air gaps between the stator/rotor; this will affect the running performance of the motor. In addition, the operating current of the DC motor is relatively large, and the power consumption is also large. Therefore, although this scheme was started to be tested in the early 1990s, no commercial product has been formed yet.

(2) AC permanent magnet synchronous motor (gearless) drive. AC permanent magnet synchronous motor is an ideal choice for MRL elevator traction machine. Generally, it consists of three parts: disc type permanent magnet motor, brake and traction sheave. The neodymium magnet part of the motor is made of rare earth permanent magnet material. The rare earth permanent magnet material has a large magnetic energy, so the motor volume can be smaller. Because there is no slip loss, there is no deuterium magnetic loss and the stator copper loss is relatively small. The power factor is approximately equal to 1 and the efficiency is high. This flat disc traction machine can be installed anywhere in the hoistway. Although the current price of this kind of motor is still high, its performance-price ratio is high and it has been recognized by the market. China is rich in rare earth permanent magnetic mineral resources. In the future, with the advancement of technology, the price of permanent magnet motors will decline. Therefore, the use of rare earth permanent magnet motors as the driving motor for elevators (not only MRL elevators) has a very broad prospect.

(3) External rotor motor (without gear). As shown in Figure 1, the motor is an inner stator with the rotor on the outside and is coaxial with the stator. Its traction sheave is mounted directly on the rotor and does not require a separate transmission or traction sheave. From traction steel

The transmission of drag between the wire rope and the car is straightforward. Compared with the conventional device, its loss is relatively small, and the motor is driven by a variable voltage variable frequency (VVVF). However, in order to generate enough torque, its radial and axial dimensions are large, and the support of the shaft extension increases the length, weight and volume of the motor, which will bring it to be used as a traction machine of the MRL elevator. A certain influence.

(4) Self-propelled traction machines. In 1997, at the 2nd China International Elevator Show held in Shanghai, Schindler exhibited a Schindler Mobile elevator with a traction machine placed under the car. The ladder is driven by a geared AC traction machine underneath the car to drive the car up and running, also known as a self-propelled elevator. The drive system uses a special self-supporting aluminum cylindrical component that can be pre-assembled on the carpet, facilitates transportation, and is quick to install.

3, using thin thin control cabinet
In order to meet the requirements that can be installed in the hoistway, some manufacturers have designed and manufactured thin and thin electric control cabinets. The volume of the control cabinets produced by some manufacturers is only 1/3 of that of the conventional ones.

4, the choice of traction wheel installation location
(1) The traction machine is installed at the top of the hoistway. This scheme is mostly adopted by European manufacturers.
(2) The traction machine is installed at the bottom of the hoistway. This scheme is mostly adopted by Japanese manufacturers. This may be because the country is an earthquake-prone country. This scheme is conducive to safety.

5. Factors to improve the competitiveness of elevators in the no-room elevator market
In addition to the performance characteristics of an elevator, MRL elevators still need to have the following competitive characteristics:
(1) The price is appropriate;
(2) Short lead times;
(3) Large traction capacity and high speed;
(4) High utilization rate of well area;
(5) The elevator installation and maintenance personnel have easy access to the traction machine and are easy to install, commission and repair.

Third, Switzerland Schindler SMART type machine room elevator
Currently, price is a major factor in MRL elevators' ability to increase their market competitiveness. Swiss Schindler has improved and upgraded matured elevator technology to produce SMART MRL elevators. It uses a universal AC induction motor and a rugged gearbox as a traction machine. It is mounted on a dedicated T-shaped track at the top of the hoistway. In this way, the cost is reduced, its price is almost the same as the price of the traditional traction machine, and the delivery time is shortened and the risk is reduced.

Fourth, the market situation of machine-roomless elevators
At present, the main markets of MRL elevators are as follows.
(1) European market. About 5,000 to 6,000 new elevators are available each year for MRL elevators, of which at least 500 are MRL elevators. Accompanied
The increase in the load, speed and lift height of the MRL elevator and the reduction in the price will gradually increase the demand ratio of MRL elevators.
(2) Asian markets. Mainly in Japan, since 1998, almost all Japanese elevator manufacturers have produced MRL elevators. Now, MRL elevators with a maximum speed of 1.75m/s, a load capacity of 1000kg and a lift height of 60m have been used in residential and commercial buildings. There is 40%~60% of MRL elevator sales in the Japanese domestic market. It is estimated that in the next few years, the market capacity of Japanese MRL elevators (including as elevators) will be approximately 6,000 to 8,000 units. China and other Asian countries are potential markets for MRL elevators.
(3) The American market. At present, there are fewer MRL elevators, but it is estimated that there will be 6,000 units of market demand in the next few years.

V. Formulation of Machine-room-free Elevator Standards
With the rapid development of machine-room-less elevators, it is necessary to set standards for MRL elevators, including safety standards, and to formulate standards that meet environmental protection in order to emphasize energy conservation, resource conservation, and environmental pollution.
The future development of machine-roomless elevators needs to consider two issues:
(1) For buildings: To reduce the vertical load, there is a simple and good shockproof structure.
(2) Towards high-load and medium-high heights.