JPH0150785B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement of a belt transmission using a variable diameter speed change pulley, and in particular, to an improvement in a belt transmission using a variable diameter speed change pulley, and in particular to a belt transmission in which an input shaft and an output shaft are arranged coaxially to handle a large output load. The present invention relates to a transmission that is reliable, durable, and easy to maintain.

[Prior art]

Methods for continuously controlling the rotation speed of the output rotating shaft can be roughly divided into pure electrical methods and pure mechanical methods.

Purely electrical systems include the Ward Leonard control system using a DC motor and the inverter control system using semiconductor thyristors. Pure mechanical systems include a torque converter system that uses hydraulic pressure, a metal friction system such as a ring cone transmission or a Beyer transmission (both are trade names), and a ratchet system that controls the feed rate of the ratchet. Furthermore, a transmission system using a belt exists as a known power transmission system.

However, in pure electric systems, the two quantities of the rotary power system and the speed change control system are generally sent to the electric motor in one line, so while it is easy to perform speed change control, various problems remain. DC motors require separate equipment such as a DC power supply, and maintenance costs increase due to deterioration of the insulation of the DC motor. In addition, the semiconductor inverter system suffers from lower rotational efficiency and torque response at low speeds due to harmonic components, and is also a cause of radio interference and noise interference.

In addition, although pure mechanical systems can transmit power smoothly, they require an operator to be nearby at all times when changing gears, making automation difficult. Moreover, pure mechanical transmission systems generally have the disadvantage that it is difficult to absorb instantaneous shocks applied to the transmission control section and to improve transmission efficiency at the same time. That is, for example, the torque converter system absorbs the shock caused by sudden changes in the gear ratio, but on the other hand, the transmission efficiency is extremely poor. In addition, even though the metal friction method has excellent transmission efficiency, the metal contact transmission part is easily damaged by instantaneous impacts.Furthermore, once damaged, subsequent gear shifting operations are hindered, and furthermore, on-site repairs are required. Since this is not possible, it is necessary to bring it to the factory, which requires a large amount of economic consumption.

In contrast, compared to other mechanical transmission systems, belt transmissions have the potential to simultaneously solve the problems of both absorbing instantaneous shocks and improving power transmission efficiency. We are prepared. In other words, Tetron, polyester, steel cord, etc. have been used as the core tensile material in transmission tension belts such as belts, but materials with even better tensile strength and bending fatigue have been developed, and transmission materials However, materials with even higher coefficients of friction and higher transmission efficiency have begun to be developed, such as polychloropyrene and polyurethane.

For this reason, although belt transmissions are expected to be used, the structure of conventional belt transmissions uses the rotating shaft of the induction motor as the input shaft, and the driving side and driven side speed change pulleys are installed on this shaft and the output shaft, respectively. The structure is such that it is pivoted to a single housing. Therefore, the input shaft and output shaft are introduced and pulled out on one plane side of this housing, and the other plane side is left as a space, which is used as a space for belt replacement work. was.

Therefore, in order to further reduce the output of the driven side of the belt transmission, which also functions as a stepless speed increaser, a gear reduction gear has been placed on the same plane side of the above-mentioned casing as the plane on which the electric motor is mounted. However, since the gear reducer must be immersed in oil, it has been essential to separate the belt transmission and gear reducer into separate housings.
For this reason, the structure has been such that the final speed change output shaft is led out from the gear reducer.

〔problem〕

Conventional belt transmissions using such variable diameter pulleys have had two problems due to structural defects.

One is that the size and type of load equipment to be applied is restricted due to structural constraints such as the input/output shaft, and the other is that the input/output shaft of the belt transmission itself is fixed between the shafts. This makes maintenance work such as belt replacement complicated.

In other words, the problem with the former is that, as already mentioned, the belt transmission and gear reducer are constructed in separate housings, so the total weight of a high-output transmission increases significantly, and the electric motor, transmission, and reducer are Since each part is only fixed irregularly, it causes unnecessary vibration and noise during high-speed operation, making it practically unusable. Moreover, from a maintenance standpoint, when a failure occurs in a part of the equipment, it is necessary to remove each piece of equipment, making it essential to remove the entire equipment from the load equipment one by one. Furthermore, in the case of load equipment that requires a wide flat space, such as an axial blower fan, the conventional transmission structure described above requires a transmission with an unbalanced configuration in the air flow path. However, there was a drawback that it was difficult to create a smooth airflow. With conventional structures, the load equipment that should be applied is limited to fields such as food machinery, where the shaft output is small and the inconvenience of the external shape can be ignored, which naturally limits the scope of application. Ta.

Furthermore, a problem with maintenance work for the latter belt transmission is that since the shafts are fixed, replacing the belt requires disassembling the transmission pulley itself. As already mentioned, conceptually this means that the other plane of the transmission housing has to be secured as a work space, and this point is a major reason why the concept of construction of conventional belt transmissions is fixed. I was used to it.

However, as long as the belt transmission is operated manually, the frequency of belt replacement is low, but when continuous automatic operation is performed 24 hours a day, the belt wears quickly and the frequency of belt replacement increases. As a result, ease of belt replacement and maintenance has been desired.

[Technical means to solve problems]

The present invention has been made in order to solve the above-mentioned drawbacks, and in particular, in order to correct the drawbacks of the conventional pure electric or pure mechanical transmission system, the part that transmits the main power to be shifted can be continuously increased or decreased. Due to the mechanical configuration consisting of a variable diameter belt transmission device that performs high-speed operation,
In addition, the part that controls the gear ratio is connected by an electrical configuration consisting of a circuit device, and further by an electromechanical conversion mechanism consisting of a pilot control device that converts electrical signals into mechanical signals, forming mechatronics. This is what I did.

In addition, the power transmission device as a mechanical component is
By installing a variable diameter belt transmission in the first stage and a constant speed ratio belt reducer in the next stage, connecting both to each other through an intermediate shaft, and forming the input shaft and output shaft to be coaxial, the overall structure can be improved. A power transmission device is formed which is collectively housed within a single housing.

[Effect]

With this configuration, the input shaft and output shaft are arranged coaxially, and the entire structure can be integrated into a single housing, so the housing structure can be changed without making any changes to the structure of the internal transmission device. It can be applied to any type of load equipment just by changing the , and the overall load balance can be stabilized even when applied to extremely high output load equipment, so the application and range of applications of transmissions can be greatly expanded. It became.

Furthermore, as a pilot control device, it was driven not only by manual operation such as rotating the steering wheel via gears as in the past, but also by electrical control signals, paving the way to a fully automated transmission.

Furthermore, with full automation in order to expand the range of application of belt transmissions, firstly, speeding up maintenance, secondly, applicability to adverse outdoor conditions such as rainwater, dust, and salt atmospheres, and furthermore, Thirdly, there are three demands to be solved: improving the reliability and durability of the internal equipment of the transmission, and the present invention has solved all of these issues.

That is, in the first belt replacement/maintenance, the upper and lower belts can be removed and replaced at once by sliding the intermediate shaft.

Second, since the entire unit is housed in a single housing, it is easy to make it airtight or semi-sealed, and even if it is sealed, a blower device can be installed to cool the room, making it possible to Fresh cooling air can be introduced. Therefore, it is possible to operate perfectly even under adverse outdoor conditions and atmospheres.

Furthermore, in order to improve the reliability and durability of the third belt transmission, forced ventilation cooling is performed inside the housing chamber to prevent the belt from deteriorating at high temperatures. In addition, the start control circuit prevents wear and tear on the belt core due to high-speed start-up, thereby extending the life of the belt.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The transmission device of the present invention will be described as a transmission for a cooling tower blower that utilizes contact between water and air, for example.

FIG. 1 shows the relationship between a suction type countercurrent cooling tower, an electronic control device, and a centrifugal chiller. Note that although a refrigerator is disclosed as an example, any other heat source may be used. Reference numeral 10 is a countercurrent cooling tower, which has an FRP body side plate 11 and a water tank 12, which are formed into a tapered shape in consideration of fluid dynamics, and a punched metal louver 13 is provided between the two to suck air. form the mouth.
Inside, the usual filling material 14, watering conduit 17, watering pipe 15 and eliminator 16 are arranged in a known manner. Cooling water flows from the inlet 18 to the water conduit 1
7. The water is scattered into the filler 14 through the four pipes 15 and flows from the water tank 12 to the outlet 19 via the drop tank 20.

There is an air outlet 21 above the body side body 11, in which eight pipe stays 23 are arranged radially, and a blower device 25 is attached to the center thereof. This blower device 25 includes a three-phase induction motor 29
A belt power transmission device 26 sealed with a box-shaped frame 27 and a lid 28, and an axial blower fan 24 are integrally assembled. In order to insulate indoor heat generated by the box-shaped frame 21 of the air blower 25, cooled outside air with low humidity is introduced into the sealed chamber from the inlet 32 via the pipe 31 and discharged from the outlet 33. With the exception of the blower 25 and piping 31, cooling towers of this type are known. A centrifugal blower fan may be used as the blower fan. Such a cooling tower 10 is used in various fields such as the chemical industry, the steel manufacturing field, and the electric power field.
and 36, and cooling water is circulated between the condenser 42 and the cooling tower 10 by a pump 49. As is well known, the turbo refrigerator 40 includes a compressor 4
1, a condenser 42, an expansion valve 43, and an evaporator 44 are connected by refrigerant pipes 45, 46, 47, and 48, respectively. Although the explanation of the operation of this refrigerator 40 is omitted here,
It should be mentioned that the condenser 42 must dissipate the heat generated therein to the outside, ie to the cooling water.

On the other hand, the blower device 25, which constitutes the main part of the present invention, is
Wiring 30 including three-phase power line a, signal lines b and p
is connected to a three-phase AC power source 37 and an electronic regulator 50 via. The regulating device 50 supplies a signal for proportionally controlling the gear ratio of the transmission device 26 via the signal line b according to the temperature signal of the dry bulb temperature sensor 51 of the outlet cooling water, and also sends the switch output signal to the power line 39. It is also supplied to a contact switch 39 provided in the main motor 29, and performs automatic control such that the operation of the main motor 29 and the operation of the adjustment device 50 and the transmission device 26 are in harmony with each other. Further, the signal for controlling the gear ratio of the transmission device 26 may be based only on the outlet cooling water temperature, but the adjustment device 50 can be modified in various ways, for example, as shown in FIG. It is also possible to compensate and control the cooling capacity of the cooling tower 10 depending on weather conditions. For this purpose, it is possible to add an outside air condition detector 52 to the bridge circuit in the regulating device 50, and to detect this outside air condition, an outside air wet bulb temperature detector or an outside air wet bulb temperature detector,
An outside air enthalpy detector may also be used, and an even cheaper detector is an outside air temperature detector 5 as shown in FIG.
3 and an outside air humidity detector 54 may be used to perform outside air compensation.

Next, the configuration of a blower device 50 that constitutes a part of the blower control device of an apparatus according to an embodiment of the present invention will be explained with reference to FIGS. 2A to 2F.

FIG. 2A shows a blower device 2 which is the main part of the present invention.
5 is disclosed. Note that the same reference numerals are used for the same components as in FIG.

The variable air blow control device 26 is composed of the usual induction motor 29, the belt power transmission device 26, and the air blow fan 24 as described above. In this embodiment, these three elements are assembled together, but as will be described later, the blower fan 24 is installed at the cooling tower air outlet 21, and the electric motor 29 and part of the transmission device 26 are connected to the air. It is also possible to install it near the outside of the air outlet 21 and connect the two. Since the normal three-phase AC induction motor 29 is placed in a humid atmosphere inside the cooling tower air outlet 21, a closed type is used, and a small heat-insulating fan 55 is provided. As is well known, there are a stator 56 and a rotor 57 inside the electric motor 29, and an input rotating shaft 60 is supported by two bearings 58. The electric motor 29 is bolted to the box-shaped frame 27 of the belt transmission device 26 via a flange 59, and its rotating shaft 60 projects and extends into the frame as a power input shaft. On the other hand, in order to reduce the weight of the belt power transmission device 26, a sealed chamber 61 is formed by a frame body 27 and a lid body 28 which are formed by casting an aluminum alloy. A drive-side pulley device 62 is attached via a key to the tip of the input shaft 60 that has entered the sealed chamber. This pulley device 62
forms an initial stage transmission, that is, a variable diameter belt continuously variable transmission 65 together with a driven pulley device 64 connected via a variable belt 63, and an intermediate rotating shaft 66.
It transmits rotational power to. The drive-side and driven-side pulley devices 62 and 64 include fixed pulleys 62a and 64a and a sliding pulley 6 having conical inclined contact surfaces 62c and 64c, respectively, as shown.
2b and 64b, and a variable belt 63 is formed between each pulley.
The inclined surfaces of the fixed and sliding pulleys are arranged so as to face each other so that the fixed pulley and the sliding pulley can be clamped. However, the vertical positions of the fixed pulley and the sliding pulley are reversed between the driving side and the driven side, so that the belt 63 can be maintained horizontally even when the variable belt 63 moves from side to side. Further, the driving pulley device 62 is integrally assembled with a speed change controller 67 for forcibly controlling the distance between the inclined surfaces of the fixed pulley 62a and the sliding pulley 62b from the outside. This controller 67 has a control column 70 supported via bearings 68a and 68b between a cylindrical portion 62d of a pulley 62a and a cylindrical portion 62e of a pulley 62b that are fitted via oilless metal. Furthermore, the screw groove 7 provided in this pillar 70
It also has a guide 72 screwed into the guide 1 . A sprocket 73 is fixed to the tip of the control column 70 for connection to a pilot controller, which will be described later, via a chain 74. When the control column 70 rotates with the rotation of the sprocket 73, the guide 72 moves up and down with respect to the column 70 due to the screw groove 71 thereof. Accordingly, since only the sliding pulley 62b slides up and down with respect to the fixed pulley 62a, the contact circle radius between the belt 63 and the pulley device 62 can be variably controlled. On the other hand, in the driven pulley device 64, the sliding pulley 64b is a coil
The pulley 6 is always fixed at a predetermined spring pressure by the spring 69.
4a, and when the belt 63 moves due to the operation of the driving pulley device 62, the sliding pulley 64 automatically moves against the spring 69.
b moves up and down, and as a result, the speed of rotation of the intermediate shaft 66 is changed by both the driving and driven pulleys. Such a variable diameter belt transmission 65 functions both as a speed increaser and a speed reducer at the point where the radius of contact with the belt on the drive side and the driven side match, that is, at a speed ratio of 1:1. . Particularly, as a transmission device for a cooling tower, it is advantageous to provide such a variable diameter transmission 65 at the first stage and to also operate this transmission 65 as a speed increaser, as will be described later.

Next, the intermediate shaft 66 connects its center portion to the cylindrical support 8 through two bearings 81a and 81b.
0, and further this support 80
As described in FIG. 2F, it is slidable on a stand 86 indicated by a broken line, and a take-up mechanism 84 consisting of a stud bolt 82, a nut 83, and a protrusion 85 on the bottom of the frame allows the input and intermediate shafts to be moved. The distance can be easily adjusted by removing the lid 28.

Further, a small-diameter constant-speed pulley 91 is attached to the lower free end of the intermediate shaft 66, and three V-belts 92a, 92b, and 92c are attached to the output rotating shaft 95 in three belt grooves provided on the side wall of the pulley. It is also wound around a large diameter constant speed pulley 93 to form a speed reducer 90 with a constant speed reduction ratio. Furthermore, in this embodiment, since the output shaft 95 and the input shaft, that is, the motor rotor 60, are axially aligned, the take-up mechanism 84 is used to adjust the belt tension and perform other maintenance work. It can be done easily.

On the other hand, the output shaft 95 is supported at its center by an output flange 99 via two bearings 96a and 96b. This flange 99
are upper and lower flanges 99a and 99c.
are fixed to the frame 27 and a circular installation stand 100 provided at the center of the stay 23, respectively. It also protrudes downward through the through hole of the installation base 100 and passes through the protruding holder 99b, and at its tip, the output shaft 99 is connected to the oil seal 97 and stopper lid 98.
The fan mounting portion 95' of No. 5 is extended. This mounting part 95' has four blade bodies 101 and a mounting tool 1.
A conventional blower fan 24 having a 02 is mounted by means of two nuts.

In addition, the sliding pulley 62 of the drive-side pulley device 62
A heat-insulating blower device 67 consisting of an impeller 77 that rotates together with the pulley and an eccentric casing 76 is attached to the back side of b, and serves to introduce outside air with little moisture into the room 61. On the other hand, the air heat-exchanged in the room 61 is exhausted to the outside through the discharge port 33 arranged on the top surface of the lid 28. Since the static pressure in the room 61 is high, high humidity outside air will not flow backward through the discharge port 33 and enter. casing 76
may be a spiral-shaped sirotsk fan.

FIG. 2B shows a sectional view taken along line B-B' of FIG. 2A. Re-explanation of the portion described in FIG. 2A will be omitted here. In FIG. 2B, the relationship between the speed change controller 67 and the pilot electric controller 110 and the cylindrical support 80 are shown.
The structure is mainly described. The frame body 27 has an elliptical shape, and a part 27' thereof partially protrudes for installing the tension pulley mechanism 120, and a reference numeral 27'' is open for the cover body 28. A pilot electric control unit 110 is installed,
It includes a conventional recycling motor 111 held in a cover 114, a gear reducer 112 and a small diameter sprocket 113. When the electric motor 111 is driven by an external proportional signal, which will be described later, the sprocket 113 is connected to the chain transmission body 7.
4 is rotated and transmitted to the large diameter sprocket 73, and the speed change controller 67 continuously and steplessly controls the rotation of the intermediate shaft 66. On the other hand, the cylindrical support 80 has a horizontally protruding plate-like fixed arm 80a, in which three elongated holes 87a, 87b, and 87c are bored. Further, the stud bolts provided on the standing pillars 86a, 86b, and 86c, which protrude from the bottom of the frame 23 and have a platform-shaped tip, are connected to the fixed arm 80a.
Insert the elongated holes 87a, 87b and 87c,
The support body 80 has nuts 88a, 88b and 88b.
It is fixed in place. Long holes 87a, 87b and 87c
is for belt conversion and tension adjustment.

FIG. 2C is an external perspective view showing the relationship between the heat-insulating centrifugal blower device 75 and the driving pulley device 62 already disclosed in FIG. 2A. In the figure, casing 7
6 is a cylinder part 76a, a spiral part 76b and a discharge part 7
6c, and a flexible pipe 31' that communicates with the introduction pipe 31 shown in FIG. 2A is attached to the cylindrical portion. One side wall of the spiral portion 76b is connected to the pulley 62
b itself functions as a wall. The blower device 75 configured in this manner supplies cold air in the direction of the arrow as the pulley device 62 rotates. Note that this blower device 75 is not limited to this embodiment, and any device that can introduce less humid outside air into the room 61 may be used. For example, a Sirotsko fan with a DC motor may be installed on the frame,
Alternatively, only the suction type fan may be disposed in the frame and the power of the input shaft 60 may be driven by a belt speed increaser.

FIG. 2D shows a configuration diagram of the pilot electric control section 110 shown in FIG. 2B. Vertical and horizontal plate portions 116a and 116 are provided on the arm 114a of the cover 114.
On one side of the T-shaped holding plate 116 formed by b, an electric motor 111, a reduction gear 112, a gear transmission body 113 and a sprocket 73 are installed on the output shaft thereof,
Further, a terminal chamber 118 is formed on the other side. A lead wire can be connected to this terminal chamber 118 from the outside through an open end 119 of an operation lid 117. A potentiometer 131, which will be described later, is installed in the terminal chamber 118. Note that this control section 1
10 may be replaced with a known hydraulic mechanism.

FIG. 2E shows a sectional view taken along the line E-E' of FIG. 2A. FIG. 2E mainly shows the configuration of the constant speed ratio belt reducer 90 and the tension adjustment pulley mechanism 120. The belt speed reducer 90 is configured as a speed reducer in which the radius ratio of two pulleys 91 and 93 is increased so that as much power as possible can be transmitted. On the other hand, the tension adjustment pulley mechanism 120 compensates for the elongation of the belt 92, and the arm 1 is supported by a shaft 121 that is erected on the bottom surface of the frame 27.
A support column 123 is attached to 22, and a pulley body 124 that presses the back surface of the belt 92 is supported thereon. An adjustment rod 127, which is pressed against a coil spring 126, is pivotally locked at the tip 125 of the arm 122. The adjustment rod 127 is
An adjustment screw 128 attached to the frame body 27 works to adjust the pressing force on the belt 92, and one end of the screw 128 projects outside through a tapered hole made in the screw 128, and the pressing force is adjusted through a transparent drip-proof cover 129. The size can be visually checked and measured.

FIG. 2F is a perspective view showing the relationship between the cylindrical support 80 and the frame 27 already described in FIGS. 2A and 2B. As already mentioned, the support body 80 that supports the intermediate shaft 66 equipped with the pulley device 64 and the small diameter pulley 91 has stud bolts 89a, 89b and 89c inserted into the three elongated holes provided in the fixed arm 80a.
are secured through nuts 88a, 88b and 88c, and the positioning of the bearing 80 is effected by the take-up mechanism 84 described in FIG. 2A when the nuts are loosened.

The operation of the air blower shown in FIGS. 2A to 2F will be briefly described. In the present invention, in response to the rotational input power of the main electric motor 29, an increasing/decelerating type transmission, that is, a variable diameter belt transmission 65 is used as the first stage transmission, and a constant speed ratio reduction gear 90 is used as the second stage transmission. intermediate shaft 66
are connected via. Variable diameter belt transmission 65
As mentioned above, if the radius of the contact circle between the belt 63 and the two pulley devices 62 and 64 is the same, then the gear ratio is 1:1, and from this position there is also a deceleration in the speed increaser. It also works as a machine.

At first glance, this may seem wasteful since the speed is increased once and then decelerated again by the reducer 90, but this is an extremely advantageous condition for the cooling tower.

In other words, the required shaft horsepower W of the cooling tower blower fan 24 is proportional to the cube of the rotation speed N, and the maximum power is required at maximum speed increase, so if you design the transmitter based on the transmitted horsepower at this time, good. However, unlike general machine tools, cooling tower blowers have little variation in load and are relatively light in load. On the other hand, the allowable transmission horsepower W ₀ of the belt itself is determined by the product of the rotational speed N and the belt tension T, so if a transmitter that functions as a speed increaser is used, the rotational speed N is high, so the tension T can be small. Therefore, if the variable diameter pulley transmission 26, which also functions as a speed increaser, is used in the first stage, that is, the first stage transmission, it can be made smaller and lighter, which is extremely advantageous and inexpensive when installed in the cooling tower 10. Can be done. Incidentally, if the transmission device 26 is installed in one housing as in this embodiment, maintenance work is also extremely facilitated.

Next, the configuration and operation of the adjustment circuit 50 shown in FIG. 3A will be explained. The electronic control circuit device 50 here discloses an example of a servo controller for automatically controlling the cooling water temperature, and is used together with the blower device 25 of FIGS. 2A to 2F to achieve air blow control. .

In FIG. 3A, the regulating circuit device 50 includes a proportional regulating circuit 130 and a part of the pilot electric controller 110;
Furthermore, it consists of three circuit parts including a soft start starting control circuit ₁₆₀ , and as shown in _{FIG .} ing. A power supply line 155 is connected to the regulating circuit device 50 from the three-phase power lines R and S phases.
Power is supplied from 156 and 156 via a voltage doubler rectifier circuit 153. The start control circuit 160 has start and stop switches 161 and 162 and three relays 1R, 2R and 3R. Electric power is also supplied from this control circuit 160 to the recycling motor 111 of the pilot electric controller 110. Note that a three-phase electric motor may be used as the electric controller 110.

The proportional adjustment circuit 130 includes two bridge circuits 1
32 and 135 are connected via a ground point 133, and the upper bridge circuit 132 is provided with a feedback potentiometer 131 (hereinafter referred to as FBP) for adjusting the gear ratio of the transmission device 26.
Also connected to the lower bridge circuit 135 is a cooling water outlet temperature detector, that is, a temperature measuring resistor 51 such as a Pt valve. This proportional adjustment circuit 130
Here, an example is shown in which the rotational speed of the blower fan is controlled only by the cooling water outlet temperature. On the other hand, the outputs of each bridge circuit 132 and 135 are supplied to operational amplifiers 137 and 138, respectively.
After being preamplified here, the respective outputs x and y are produced via a resistor at a node 141 into a deviation signal which is further applied to an operational amplifier 142 . Note that the state of the gear ratio or the cooling water temperature is indicated by the indicator 140 via the changeover switch 139. The deviation signal output of the amplifier 142 is transmitted to the filter 1
The signal is input to the operational amplifier 144 via 43. The non-inverting input of this operational amplifier 144 receives positive feedback from its output via a resistor, and the inverting input receives negative feedback via a known dead band circuit 145 consisting of four diodes. This is to prevent output hunting.

The output of the amplifier 144 is further supplied to a speed-increasing drive circuit 146 and a decelerating-side drive circuit 147,
The activation of relays 150 and 151 is controlled via respective semiconductor switches 148 and 149. A contact 2R4 is connected in series with the semiconductor/switch 148 to the speed increasing circuit 146, and a contact 2R2 is connected in parallel to the semiconductor/switch 149 in the decelerating circuit 147. On the other hand, relays 150 and 151 have output contacts 150a and 151a, and control the rotation of recycling motor 111. The electric motor 111 has a drive coil 1
11a and 111b and a capacitor 115, limit switches HS and LS are connected to the motor to prevent excessive rotation of its output.
The power supply from the power supply terminal 157 is controlled.

On the other hand, the start control circuit 160 performs a function of regulating the mutual relationship between the traction motor 29 and the recycle motor 111, and a soft start function of starting the transmission 26 from the lowest speed, that is, a light load state. It is something. There are relay 1R with normally open contacts 1R1 and 1R2, relay 2R with normally open contacts 2R1, 2R2 and normally closed contacts 2R3 and 2R4, and relay 3R with normally open contacts 3R1, 3R2, 3R3 and 3R4. It controls three circuits: a proportional adjustment circuit 130, an electric controller 110, and a main motor 29. Reference numeral 163 is a thermal protector.

Next, before explaining the operation of FIG. 3A, FIG. 3B will be described. Figure 3B shows the electronic proportional adjustment circuit 1.
30 shows another embodiment in which the cooling device 30 has a function of compensating the cooling capacity of the cooling device, that is, the cooling tower, based on the outside air weather condition signal. This embodiment has almost the same configuration as FIG. 3A, so only the different circuit parts are shown.
In addition to 1, an outside air dry bulb temperature detector 53 and an outside air relative humidity detector 54 are connected as shown. As already mentioned, cooling towers are usually affected by the amount of outside air enthalpy or the outside air wet bulb temperature.
The detectors 53 and 54 used here are intended to provide compensation that substantially approximates these quantities. In addition, in order to perform rough control with low precision, the humidity detector 54 may be omitted and control may be performed simply based on the difference between the cooling water outlet temperature and the outside air temperature. , outside temperature detector 5
3, an outside air condition detector 52 (see FIG. 1), such as a known outside air wet bulb temperature sensor or outside air enthalpy detector, is used between terminals m and n, and the output signal of the amplifier 138 is output from the cooling water outlet. It is obvious to those skilled in the art that the difference between the temperature and these outside air state quantities may be used as a control input. However, these outside air condition detectors 52 need to be able to convert the outside air condition quantity into an electrical signal, for example, a change in resistance value. Furthermore, those skilled in the art will be able to perform control based on the difference signal between the cooling water inlet water temperature and the outlet water temperature, and further, depending on the type of equipment to which this cooling device is applied, such as a refrigerator, It is well known that there are cases where it is advantageous to control the

Next, the operations in FIGS. 3A and 3B will be briefly described.
If the source switch 38 is turned on in advance and then the start switch 161 is pressed and turned on, the contacts 2R3,
Since the relay 3R is energized via the protector 163, it is self-held by the contact 3R1. Contact 3
The main motor 29 is started by closing R2, and the contact 3R
3 to the regulating circuit 130, and furthermore, by closing the power supply interlock contact 3R4, power is also supplied to the electric controller 110. At this time, relay 2R is deenergized, but when low limit switch LS is closed and adjustment circuit 130 enters proportional control operation,
Relay 1R is energized, contact 1R2 closes,
Electric controller 110 also starts operating.

First, when the cooling water outlet temperature of the cooling tower shown in FIG. 1 is relatively high, the output y of the bridge circuit 135 is
Since is higher than the output x of the bridge circuit 132, a positive signal appears at the output Z of the amplifier 142, and the output signal is supplied to the amplifier 144, and the speed increasing side drive circuit 14
6 relay 150 is driven. Along with this, contact 1
50a is reversed, the recycle electric motor 11
1 rotates in a direction in which the transmission 65 increases the speed, and passes through the chain transmission body 74 to the speed change control section 67 of the transmission 65.
This signal is transmitted to the pulley devices 62 and 6.
The radius of the contact circle between the belt 63 and the belt 63 changes as described above, and the rotational speeds of the output shaft 95 and the blower fan increase continuously and proportionally accordingly.
When the output of the amplifier 142 gradually decreases and enters the dead band determined by the dead band circuit 145, the relay 15
0 is deenergized and the operation of the electric controller 110 is also stopped,
Only the main motor 29 rotates. Conversely, when the outlet temperature of the cooling water gradually decreases and as a result, the output X becomes larger than the output Y, a negative signal is output from the amplifier 142. When the output difference reaches a predetermined value, the deceleration side drive circuit 147 is energized and the relay 151 is energized.
Only 1a is closed. Then, contrary to the above, the electric motor 111 rotates in a direction that reduces the speed of the transmission 65. Therefore, the rotational speeds of the transmitter output shaft 95 and the blower fan gradually decrease continuously and proportionally, and when a predetermined dead zone is reached, the deceleration operation is stopped and only the main blower motor 29 rotates.

Such an operation is always performed as the temperature of the cooling water changes within a predetermined proportional band defined by the adjustment circuit 160, and functions to keep the temperature of the cooling water always within a predetermined range. Also, bridge circuit 1 in Figure 3B
35' also responds to changes in outside weather conditions; for example, when the outside wet bulb temperature is substantially low, the cooling efficiency of the cooling tower also increases, so the rotational speed of the blower fan 24 changes accordingly. The adjustment circuit 160 operates to lower the amount of water.

Next, when the stop switch 162 is pressed, the relay 2R is energized via the contact 3R1 and the switch 162, and is self-held at the contact 2R1, and the relay 2R is held at the contact 2R3.
will be developed. Furthermore, contact 2R2 is transistor 1
49, the relay 151 is energized, and since the contact 2R4 is opened, the relay 150 is forcibly de-energized. At this time, the relay 3R is also energized, so the main motor 29 continues to rotate.
Since contact 3R4 is also closed, electric controller 11
0 is the transmission 65 due to the reversal of the contact 151a.
control to forcibly shift to a deceleration state.
Therefore, in the end, the low speed limit switch
Recycled motor 1 reached the point where LS was opened.
11 is stopped, and relay 1R is deenergized and contact 1R1 is opened, so relay 3R is also deenergized, rotation of main fan motor 29 is stopped, and adjustment circuit 130 is deenergized.
Power supply to is also blocked, and by opening contact 3R1, relay 2R is also released from self-holding, and the entire control system is stopped.

That is, the activation control circuit 160
The drive pulley device 64 functions to stop in a clamped state near the maximum speed reduction ratio, that is, the maximum circumference of the driven pulley device 64. This has the advantage of making maintenance work such as belt replacement or tension adjustment extremely easy, and also includes a soft start function to ensure that the next restart starts from a light load or lowest speed condition. I am accomplishing it. Therefore, not only the power consumption of the main motor 29 is reduced, but also an auxiliary starter such as a motor starter may be unnecessary in some cases. In addition, even if the low-speed side switch LS is open at startup, the speed-increasing side drive circuit 14
Since the switch 6 operates first, the switch LS is then closed, and the proportional operation of the adjustment circuit 160 is not disturbed.

〔Effect of the invention〕

As described above, according to the transmission of the present invention, the main power transmission mechanism is constituted by mechanical means, the gear ratio control mechanism is constituted by electric means, and the connecting portion between the two is constituted by electromechanical conversion means. Since it is mechatronic, it combines the mutual advantages of the mechanical and electrical parts to create the most suitable and inexpensive transmission for loads with large moments of inertia, such as blower fans. can.

In other words, a variable diameter belt transmission that performs stepless increase/deceleration as a mechanical means is used in the first stage and decelerated in the next stage, so a transmission with this structure, for example, when applied to a blower fan, At maximum speed, which is the maximum load of the fan, the speed increases by one step and then decelerates again, but this means that the tension on the belt can be reduced by that much, and the power transmission can be made smaller. It can be done. The transmission of the present invention is extremely advantageous for load equipment that requires compactness.Moreover, it has a wide shifting range and transmits data efficiently over the entire range, so it not only saves power but also reduces process variables such as cooling water temperature. It is very effective for fixed value control, etc., and is particularly effective for highly accurate process control. In addition, the variable diameter belt transmission effectively absorbs the start-up shock using the belt, and since it is not subjected to shock during normal operation, there is less damage to the mechanical parts and the service life can be extended, so its industrial value is great.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a cooling system to which a transmission according to an embodiment of the present invention is applied, and FIG.
2A is a structural diagram of each part of the transmission according to the embodiment, and FIG. 2A is an overall structural diagram of the blower. Also, Figure 2B is a sectional view taken along line B-B' in Figure 2A, and Figure 2C
shows a partial perspective view of the drive-side pulley device in the second
Figure D is a sectional view of the electrically controlled pilot control section, and Figure 2E is a sectional view taken along the line E-E' in Figure 2A.
Further, FIG. 2F is a partial perspective view of the driven pulley device, FIG. 3A is a connection diagram of a circuit device that is part of the configuration of the blower of the same embodiment, and FIG. 3B is a A bridge circuit connection diagram of another embodiment of the same circuit device is shown. In the figure, 10...cooling device, that is, a cooling tower, 25
...Air blower, 40...Turbo chiller, 50...
Electronic adjustment circuit device, 65... Variable diameter belt transmission, 90... Constant reduction ratio reducer, 110... Pilot electric control unit, 130... Adjustment circuit, 160...
Soft start activation control circuit.

Claims (1)

[Scope of Claims] 1. ○A. A variable diameter belt transmission device that performs stepless increase/deceleration operation by installing speed change pulleys between an input shaft and an intermediate shaft, and ○B. Mechanically interlocked with this belt transmission device. A pilot control device that provides a mechanical speed change signal, ○C A belt reduction device consisting of a constant speed ratio pulley provided between the output shaft and the intermediate shaft, ○D The input and output shafts are arranged coaxially with each other, and the pilot A control device is attached to a side wall portion and connected to the belt transmission device in the chamber, and the belt transmission device and the speed reduction device are housed together,
a single housing with an opening so that the periphery of the speed change pulley installed on the intermediate shaft is almost exposed, and the pulley provided at the end of each shaft has a free end on one end side The intermediate shaft is normally fixed at a fixed position with respect to the input/output shaft, and is movable in the direction of the input/output shaft only when the belt is replaced. 2. ○A. A variable diameter belt transmission device that installs speed change pulleys between the input shaft and the intermediate shaft and performs stepless speed change operation; A pilot control device that converts into a speed change signal, ○C A belt reduction device that performs deceleration operation using a constant speed ratio pulley between the output shaft and intermediate shaft, ○D The above input shaft and output shaft are arranged coaxially or nearby, and the above A single housing housing the variable diameter belt transmission device, the pilot control device, and the belt reduction device together in a nearly hermetically sealed state; , and the pulleys provided at the shaft ends of each of the above shafts are arranged so that one end becomes a free end, while the above intermediate shaft is always fixed at a fixed position with respect to the input/output shaft, and only when the belt is replaced. A transmission installed movably in the direction of the input/output shaft. 3 ○B. A variable diameter belt transmission device that installs speed change pulleys between the input shaft and the intermediate shaft and performs stepless speed change operation; ○C) A belt reduction device that performs deceleration operation using a constant speed ratio pulley between the output shaft and the intermediate shaft; ○D) A holder that supports the central part of the intermediate shaft, which is A positioning device consisting of a fixing device that is tightened to maintain a constant distance between the input and output shafts, and a hoisting device that slides when the belt is shifted; and a frame body that collectively houses the variable diameter belt transmission, the pilot control device, and the belt speed reduction device, and a lid body that seals an opening formed in such a way that the holding body can be removed while supporting the intermediate shaft. It consists of a single housing, and a circuit device connected to the pilot control device and supplying the electrical speed change signal, and one end of the pulley provided at the end of each shaft is a free end. In the transmission, the intermediate shaft is normally fixed at a fixed position relative to the input/output shaft and is movable in the direction of the input/output shaft only when the belt is replaced. 4 ○B A variable diameter belt transmission device that installs speed change pulleys between the input shaft and intermediate shaft and performs stepless speed change operation; A pilot control device that converts into a speed change signal, ○C A belt reduction device that performs deceleration operation using a constant speed ratio pulley between the output shaft and intermediate shaft, ○D The above input shaft and output shaft are arranged coaxially or nearby, and the above A single housing that houses the variable diameter belt transmission, the pilot control device, and the belt speed reducer all at once, and is equipped with an inlet and an outlet for cooling air from the outside to radiate heat indoors; a blower device disposed at any position in the air flow path of the air inlet and outlet to forcefully ventilate the cooling air; The pulleys provided at the shaft ends of each of the above-mentioned shafts are arranged so that one end becomes a free end, while the above-mentioned intermediate shaft is normally fixed at a fixed position with respect to the above-mentioned input/output shaft, and the belt is not replaced. A transmission that is installed so that it can move only in the direction of the input and output shafts. 5 ○A A variable diameter belt transmission device that has speed change pulleys installed between the input shaft and the intermediate shaft to perform stepless increase/deceleration operation; A pilot control device that converts into a speed change signal, ○C A belt reduction device that performs deceleration operation using a constant speed ratio pulley between the output shaft and intermediate shaft, ○D The above input shaft and output shaft are arranged coaxially or nearby, and the above A single housing that collectively accommodates the variable diameter belt transmission; a circuit device having a start control circuit that supplies a forced deceleration command signal from the speed change command circuit and stops rotation of the input shaft when the output shaft is at a minimum rotational speed, and a shaft end of each of the shafts. The pulleys provided on the belt are arranged so that one end is the free end, while the intermediate shaft is normally fixed at a fixed position relative to the input/output shaft and can be moved in the direction of the input/output shaft only when the belt is replaced. The transmission that has been made.