On the key technology of machine room-less elevators

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In order to meet the needs of the construction market, since the 1990s, the world-renowned multinational Elevator company OTIS.SCHINDLER.KONE.MTTSUBISHI has developed machine room-less elevators, and in 1997 the second Shanghai and the third Beijing International in 1998. At the elevator equipment and technology exhibition, the physical exhibits or video presentations of the machine room elevators were introduced.--- The machine room-less elevators are in the lower part of the construction market, the cost competition and the rapid technological progress of the elevator industry. It is not the elevator machine room. Simple local improvement, but a far-reaching and multi-faceted change in elevator technology. This is because some key technologies used in machine roomless elevators will be promoted and applied to other elevator products, which will drive the technological progress of the entire elevator industry. According to the development of the domestic and international machine room elevators and our own development experience, the key technologies of the machine room elevators are discussed.
1. The primary problem of arranging machine room-less elevators is how to arrange key parts such as car, counterweight, drive main engine, control cabinet and speed limiter in the general elevator shaft without the machine room. If the problem is solved by increasing the cross-sectional size of the hoistway or increasing the height of the top of the hoistway after canceling the equipment room, it will not be worth the candle. The main way to solve the problem of inorganic room hoistway layout is to make clever use of hoistway space, develop special Elevator Components and develop new drive modes.
---1.1 clever use of hoistway space -
The hoistway parts that can be used as the machine room-driven traction drive elevator to drive the main engine and control cabinet are:
A) The top space of the hoistway. This solution uses a specially designed flat disc drive mainframe that can be placed between the top car of the hoistway and the wall of the hoistway, and the control cabinet is integrated with the top floor door. The main advantage is that the driving main engine and the speed limiter are the same as the working conditions of the organic room elevator and the control cabinet is convenient for commissioning and maintenance. The main disadvantage is that the rated load capacity, rated speed and maximum lifting height of the elevator are complicated by the shape of the driving mainframe and the complicated operation of the emergency turning operation.
B) Well pit space. This solution places the drive unit in the pit and hangs the control cabinet between the car near the pit and the wall of the hoistway. The biggest advantage is that increasing the rated load capacity, rated speed and maximum lifting height of the elevator is not limited by the size of the drive mainframe and the emergency operation is easy. The main disadvantage is that the design of the drive unit and the speed limiter is different from that of a normal elevator, so an improved design must be made.
C) Opening space in the side wall of the shaft. This solution places the drive unit and controls within the reserved openings in the sidewalls of the top hoistway. Its biggest advantage is that it can increase the rated load capacity, rated speed and maximum lifting height of the elevator and can be equipped with the drive main engine and speed limiter used in ordinary elevators, and it is also convenient to install and repair and emergency cranking operation. The main disadvantage is that it is necessary to appropriately increase the thickness of the side wall of the top reserved hole and to install the access door outside the opening of the wall of the well.
——1.2 Develop special elevator components —
After the machine roomless elevator is cancelled, in order to meet the needs of different well arrangements, the main special elevator components that have been put into use are:
A) A new type of drive host that is compact and can meet different operating conditions;
B) Control cabinets with high flexibility, convenience and reliability;
C) a one-piece car car that is simple in construction and capable of reducing the width and height dimensions;
D) a car top rail that can be telescopically installed in order to reduce the height of the top of the shaft;
E) a new speed limiter that meets the requirements of GB7588 and can be located at different positions in the shaft;
F) a single-lift safety clamp system that can be mounted on the upper or lower end of the car frame beam;
G) a new type of buffer that meets the requirements of the GB7588 buffer stroke and has the smallest installation size;
H) Simple, convenient and safe emergency operation device.
——1.3 Development of new driving methods In order to solve the difficulties in the layout of the machine room of the machine room
The new drive methods that have been developed include linear motors that directly drive the car or counterweights, friction drives that directly drive the car, and wire belts to drive the car and counterweight. Their common idea is to deal with the problem of well layout by compressing the size of the mainframe or simplifying the transmission mechanism, as explained later.
2. How to reduce the top level of the hoistway is the second problem after the top-level high-inductive room elevator cancels the special machine room above the top floor of the building. This is because when the top of the hoistway exceeds the height of the main body of the building, it will make the installation of the machine room almost meaningless.
2.1 Car GB7588 5.7.1.1 stipulates that “the horizontal distance between the horizontal plane of the highest area of ​​the car top and the horizontal plane of the lowest part of the top of the hoistway at the projection part of the car roof shall be not less than 1.0 0.035V2(m).” and 8.1.1 It is stipulated that “the net height inside the car shall not be less than 2m.” Therefore, the only way to reduce the height of the top layer of the hoistway by compressing the height of the car under the premise of the above provisions is to select the net height of the minimum car and minimize the ceiling. Car height space.
2.2 Car top guard rail ---
GB7588 5.7.1.1 C) stipulates that “the free distance between the lowest part of the hoistway top and the highest part of the equipment fixed on the roof of the car shall be not less than 0.3 0.035V2(m).”, when the top of the car is safe In the case of guardrails, in most cases the car top guardrail will be the highest part on the roof of the car and a key factor in determining the height of the top floor. Since the purpose of setting the car top guardrail is to prevent the operator from falling into the hoistway when installing or repairing the elevator, and the car top is not allowed to stand when the elevator is in normal operation, the car top guardrail can be designed as a plug-in type, when the installation and maintenance operation is performed. When the active part is raised to a safe height and pinned, the active part is returned to the lower position before starting normal operation.
2.3 The lowest part of the hoistway top GB7588 5.7.1.1 B) and C) stipulate that the top level of the hoistway is related to the lowest part of the hoistway top. The hoistway component usually refers to the installation of the maintenance hook, the suspension bearing beam and the wire rope fixing device. In order to reduce the height of the hoistway top, the hoistway top member should be placed between the top car and the hoistway wall of the hoistway.
2.4 limit switch –
GB7588 10.5.1 stipulates that “the elevator shall be provided with a limit switch and shall be placed in a position that acts as close as possible to the end station without risk of malfunction. The limit switch shall act between the car or the counterweight contact buffer. And maintains its action state while the buffer is compressed.", and GB7588 5.7.1.1 specifies that the premise of determining the top spacing of the traction drive elevator is that when the counterweight is fully pressed on its buffer, the installation position of the limit switch is When the car is at the top layer, the counterweight is related to the installation distance of the damper, so the installation distance at which the apex limit switch works should be reduced if conditions permit, so as to reduce the installation distance of the counterweight and the damper when the car is at the top layer. Finally, the purpose of reducing the height of the top layer of the hoistway is achieved.
2.5 Counterweight In order to counterbalance the use of the hoistway section, the machine roomless elevator usually places the counterweight and the drive main unit in the same side space of the car and the hoistway wall. When the rated load of the elevator is small and the corresponding cross-section size of the hoistway is limited, the vertical direction projection area of ​​the hoistway that needs to be occupied is often compressed by increasing the counterweight height, so that the counterweight instead of the car determines the top level. There are two ways to solve this problem: one is the same as the front top limit switch and reduces the effective installation distance of the bottom limit switch; the other is to reduce the counterweight buffer without changing the counterweight and the buffer installation distance. Installation height.
3. The one-piece car car frame can not only compress the external size but also simplify the structure of the car car frame because the car car frame is integrated, so the conjoined car car frame is a kind of machine room elevator. advanced technology. #p#分页头#e#
3.1 The vertical beam is embedded in the car wall in order to compress the outer dimensions of the car frame, which facilitates the arrangement of the hoistway of the machine room-less elevator; the design advantages of embedding the car frame beam with the car car wall are three: one can reduce the direction of the car frame rail It is smaller than 100mm; its two vertical beams are complementary to the car wall and the strength is increased; the slotted space of the three-type steel vertical beam can accommodate the car control panel and open the natural ventilation hole of the car.
3.2 The upper beam is assembled into a car top —
The advantages of the one-piece car car frame combining the upper steel beam and several shaped steel plates to assemble the car top are as follows: one is to reduce the height dimension of the car car frame; the other is that the upper beam and the car roof are integrated into one another and the stiffness is complementary. The structure is simplified; the second is that the trough space of the upper beam of the steel can be placed in the axial flow fan and used as a wire trough for wiring.
3.3 can be loaded with heavy undercarriage -
The integration of the inner and outer car bottoms on the traction suspension beam is another feature of the car-mounted car frame. The benefits are three: one compresses the height of the car bottom; the second simplifies the structure and reduces the structure. The weight; the three inner and outer car bottoms are combined to increase the rigidity and strength, which is convenient for installing the weight. In order to select a small drive mainframe, the machine room-less elevator usually adopts a 2:1 traction drive. In some special cases, the car can not go down and the traction rope slips. Therefore, installing the weight on the base of the car is to solve this problem. A powerful measure of the problem.
3.4 million cushioning boots –
Since the car and the car frame are integrated and the damper device is eliminated among them, the Guide Shoe mounted on the car body of the car should use a product with multiple directional buffering functions. At present, most car Guide Shoes are provided with a spring with adjustable pre-tightening force in the direction of the rail rail top, and only a damping rubber pad is arranged in the rail rail side direction. For the one-piece car car frame, in order to make up for the canceled vibration damping device, the guide shoe with the pre-tightening force at least in the three directions of the car rail rail top and the rail side should be selected to increase the car to the car. Vibration reduction. If the universal buffer guide shoe is selected, the vibration damping effect may be better, which can be selected in the current elevator accessory products.
3.5 Traction suspension beam -
The 2:1 splicing one-piece car car frame is generally placed on the suspension beam by means of a vibration-damping rubber pad, so that the drive main body can drive the car by winding the wire ropes of the two return ropes mounted on the suspension beam. The car moves up and down along the guide rails. In order to prevent the vibration damping device from being crushed or misplaced when the car is overloaded or bottomed, a limit and anti-jump bolt should be placed between the car body and the suspension beam. In addition, in order to reduce the vertical and horizontal vibration of the car during operation, the damping rubber pad should have stable working stiffness and long service life.

4. Drive mode -
The development of various new driving methods is an important development direction of machine roomless elevators. Ordinary elevators usually use a 1:1 wire rope traction drive because they can be placed in a machine room with sufficient space. For the machine roomless elevator, if the new driving method is not adopted, it is difficult to solve the problem of the hoistway arrangement, so the following various new driving modes appear.
4.1 Wire rope traction drive - this drive mode has two major changes with the traditional wire rope traction drive; one is to use a 2:1 traction ratio to double the traction drive torque and double the traction wheel speed Later, the size of the drive mainframe was compressed; the second was to develop a flat-disc synchronous toothless drive mainframe so that it could be placed between the upper car and the hoistway wall.
4.2 Steel wire belt traction drive - A major improvement of this driving method is to use a flat steel wire belt instead of a circular wire rope, so that the diameter of the traction sheave is greatly reduced under the same rope ratio, plus 2:1 The traction ratio further reduces the traction drive torque and the traction wheel speed, thus greatly reducing the size of the drive unit so that it can be easily placed between the top floor car and the hoistway wall.
4.3 Linear motor drive--This kind of driving method can not be counterweight. The permanent magnet is directly mounted on the car and the coil is fixed on the hoistway wall of the corresponding side. The linear motor directly drives the car to move up and down. Alternatively, the coil can be mounted on the counterweight to fix the permanent magnet to the hoistway wall on the corresponding side, and the linear motor can be used to indirectly drive the movement of the car.
4.4 Friction wheel drive--This type of driving method is to install the drive main unit with the friction wheel directly on the bottom of the car, make it contact with the special car Guide Rail and apply a certain positive pressure by the pressure roller, so as to drive the main engine. The friction generated by the friction wheel rotates to drive the car to move up and down along the guide rail.
The above four driving methods have appeared successively in order to solve the well layout of the machine room-less elevators. Each has its own advantages and disadvantages, and needs to be improved and perfected. Which way can stand out and be tested through market competition and long-term use.
5. Control System –
Since the machine roomless elevator does not have a machine room, its control system has higher flexibility, convenience and reliability than ordinary elevators.
5.1 Flexibility - In order to facilitate electrical wiring, the control cabinet of the machine roomless elevator is usually placed close to the drive mainframe. There are three main forms: one is when the drive mainframe is installed in the pit of the hoistway, and the control cabinet is placed on the top layer and the layer The door is made into a joint type; the second is when the driving host is installed in the pit of the hoistway, the control cabinet is placed between the car at the bottom of the hoistway and the wall of the hoistway and is made into a wall-mounted type; and the third is when the driving main body is installed in the opening space of the hoistway wall When inside, the control cabinet is placed in the same opening and made portable.
5.2 Convenience -- The convenience of the control system of the machine roomless elevator mainly refers to the following aspects: the selection and installation of the first electrical equipment should be beneficial to the well circuit of the power circuit, safety circuit, lighting circuit and control circuit in the hoistway. The shape of the second control frame should meet the special size requirements of the connected type, wall-mounted type and portable type; the third control cabinet should be designed to meet the special installation requirements of the connected type, wall-mounted type and portable type; The position of the cabinet and the form in which it can be used can be checked.
5.3 Reliability--The hoistway arrangement of the machine-room-less elevator is much more compact than that of the ordinary elevator, which increases the difficulty of overhauling the control system and should therefore have higher reliability. Special attention should be paid to the following issues in the design: First, the electrical equipment and components selected by the control system should have a long service life and high operational reliability, so as to reduce the maintenance workload; second, the control cabinet placed near the hoistway It is easy to interfere with electrical lines, so more powerful software and hardware anti-jamming measures should be taken in the design of control system. Third, advanced technology of serial communication should be adopted to reduce the number of well cables and wires and improve the reliability of signal exchange. .
6. Emergency operation -
GB7588 12.5.1 stipulates that “If the car with the rated load is moved upwards, the required operating force is not more than 400N. The elevator drive main unit should be equipped with manual emergency operation device to move the car to a layer by using a smooth hand wheel. Station.” In addition to the difficulty in arranging the wells, the machine roomless elevators generally do not use emergency backup power for emergency operations. Therefore, how to install manual emergency operation devices is also a major problem for machine roomless elevators. There are three specific difficulties: how can an emergency operation device be easily and conveniently engaged or disengaged from the drive host; the second operator stands where the emergency operation is performed; and the third is how to check whether the car enters the unlocking door area.
6.1 Top-level hoistway outer disk--When the drive main unit is placed in the top floor of the hoistway, a hole is opened at the top floor door. The operator stands outside the top floor door and opens the drive main brake by a special mechanism, and then uses the car and the counterweight. The weight difference drives the car to move while observing whether the car enters the unlocking door area through the landing door opening. The main problem with this method is that when the car and the counterweight approach the balance load, it is not possible to ensure that the car produces motion. In addition, the operation of controlling the movement of the car by means of the brake is not safe enough. #p#分页头#e#
6.2 Bottom-hole hoistway--When the drive mainframe is placed in the pit of the hoistway, the operator enters the pit to perform the car-carrying operation as simple and convenient as the operation in the machine room, but the problem is that when the parking fault happens, the car is at the bottom of the lock. When the area is above the area, the operator cannot enter the pit. If the access door can be installed at the pit, this problem can be solved.
6.3 Well outside the platform of the hoistway--When the drive main unit is placed in the opening space of the hoistway wall, the operator can open the inspection door and stand on the platform for the car operation. The problem with this method is that when the access door can be installed inside the building, the operator can operate with the temporary platform, but if the access door must be installed outside the building, it is necessary to set up a ladder and a simple cantilever platform outside the building. .
7. Ventilation lighting -
How to deal with hoistway ventilation, machine room ventilation and machine room lighting after the machine roomless elevator does not have a machine room is a problem that is easy to ignore.
7.1 Well ventilation--GB7588 5.2.3 stipulates that “ventilation holes shall be provided at the top of the hoistway, and the area shall not be less than 1% of the horizontal section area of ​​the hoistway. The venting holes may be directly led to the outside or to the outside through the machine room or pulley room.” The top of the hoistway of the organic room elevator is usually provided with openings such as cable wires, traction wire ropes, speed limiter ropes, etc., and the total combined area can generally reach the ventilation requirement of 1% of the cross-sectional area of ​​the hoistway, so there is no need to open special ventilation holes. For the machine roomless elevator, after the machine room is cancelled, special ventilation holes should be opened at the top of the hoistway. Otherwise, it will not meet the requirements of GB7588, and it will also increase the running noise of the elevator.
7.2 Ventilation of the engine room -- GB7588 6.3.5 stipulates that “the machine room must be ventilated to protect the motor, equipment and cables so as to be free from dust, harmful gases and moisture.” and 6.3.5.2 “in the machine room” The ambient temperature should be maintained between 5 and 40 degrees." For the inorganic room traction drive elevator, the drive mainframe usually adopts the upper part of the top floor, the lower part of the pit and the inner side of the hole of the hoistway wall, which can be seen from the hoistway. It is used as a machine room, so well ventilation is considered in the design. It can meet the ventilation and temperature requirements of GB7588 for the equipment room.
7.3 Room lighting -- GB7588 6.3.6 stipulates that “the machine room shall be provided with fixed electrical lighting. The illumination on the floor surface shall be not less than 200LX. The lighting power supply shall comply with the requirements of 13.6.1. The appropriate height in the machine room near the entrance shall be There is a switch to control the lighting of the equipment room when entering. One or more power sockets should be installed in the equipment room." The main purpose is to provide sufficient illumination for the installation, commissioning, maintenance and emergency operation of the elevator in the equipment room. For the machine roomless elevator, the lighting power supply, power switch and power socket should be designed according to the above requirements according to the installation position of the drive host and the control cabinet to ensure that the drive main unit, control cabinet, speed limiter and other components can be installed under sufficient conditions. , commissioning, maintenance and emergency cranking operations.
8. Main parameters -
Since the machine roomless elevator does not have a machine room, the three main parameters of the rated load capacity, rated speed and maximum lifting height are restricted by the layout of the well.
8.1 Rated Load Capacity - One of the key technologies for traction-driven machine room-less elevators is how to compress the dimensions of the drive unit to solve the difficulty of hoistway layout. Traction torque is one of the main factors determining the size of the drive unit, and it is directly related to the load capacity and the diameter of the traction sheave. GB7588 9.1.1 and 9.2.2 respectively specify that the nominal diameter of the traction wire rope is not less than 8 mm and the ratio of the diameter of the pulley of the traction sheave to the nominal diameter of the wire rope is less than 40. Under the premise of satisfying the above requirements and the same load, there are three ways to reduce the traction torque: one uses a 2:1 traction ratio to reduce the pulling force of the wire rope by half; and the second 8mm wire rope is driven by the traction to make the traction The diameter of the wheel hub is reduced to 320mm; the third is driven by a wire belt to reduce the diameter of the traction sheave.
8.2 Rated Speed ​​- The rated speed of the machine roomless elevator is another important factor in determining the size of the drive unit. Increasing the rated speed of the elevator operation will inevitably increase the driving power of the motor and the reducer, which will undoubtedly lead to an increase in the size of the drive main body, which also brings difficulties in the arrangement of the hoistway. In addition, increasing the rated speed will also bring new problems to the machine roomless elevators to reduce vibration and noise.
8.3 Maximum lifting height - Another major parameter that restricts the layout of the machine room elevator is the maximum lifting height. Its influence is mainly reflected in two aspects: one aspect is that increasing the elevator lifting height will increase the weight of the car suspension wire rope, the accompanying cable and the balance compensation chain, so the traction torque will increase accordingly, and finally the drive mainframe dimensions will be increased. It is difficult to increase the layout of the hoistway; on the other hand, the main engine of the machine room, the suspension rope head, the return rope pulley, the speed limiter and other components are often installed on the car guide rail, the counterweight guide rail or the load-bearing beam fixed to the inner wall of the hoistway. Therefore, increasing the lift height of the elevator will also increase the supporting force of the guide rail, the load-bearing beam and the inner wall of the shaft. In summary, the rated load capacity, rated speed and maximum lifting height are both constraints on the use of machine roomless elevators and the development of elevator technology. The three main parameters of the machine room-less elevators currently on the market are mostly 1000kg, 1.0m/s and 40m. In the future, with the emergence and development of various new technologies, the three main parameters will gradually increase.