JPH023073B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention improves the durability of the belt and speeds up replacement work, which occur when a continuously variable power transmission equipped with a speed change belt and a variable pulley is operated fully automatically. This paper relates to improvements to transmissions to solve the problem of

[Prior art]

FIG. 5 shows a schematic configuration diagram of a conventional belt transmission. In the diagram, A is the electric motor, B is the belt transmission, C is the housing, D is the operating handle, E is the output shaft, and F
is the input axis. Further, the housing C is composed of a frame G and a plurality of lids K, J, and I, and inside thereof, a speed change belt M is wound between variable pulleys L and N on the drive side and the driven side. Further, O and P are bearings.

The speed change operation is performed by rotating the operating handle D, causing the hoisting screw D' to move the lever K and sliding the disk wheel of the variable pulley L. In this case, the input shaft F is the motor rotation shaft, and the variable pulley L is installed at its free end, inserted from the a-side plane of the frame G, and fixed with a flange. On the other hand, the output shaft E has a structure in which bearings O and P are arranged on both sides of the variable pulley N, and the bearings O and P are supported by the left and right lids I ₁ and I ₂ . There is.

〔problem〕

However, when manually controlling the gear ratio of a belt transmission with such a structure, in the field of general industrial machinery, the operator manually turns the operating handle D.
The average number of operations per day is about 6 to 8 times. However, with this level of gear shifting frequency, there is little belt friction, and because a person needs to be present, the vehicle is operated less frequently at night, resulting in less overall operating time. Therefore, the impact applied to the belt M is small, and the rate at which the belt M is damaged or rubbed is extremely low. Therefore, as long as such manual operations are performed, belt replacement is infrequent and the belt has a relatively long life.

However, when a conventional belt transmission, which has been designed and manufactured in advance under such operating conditions, is operated fully automatically, weaknesses in its durability quickly become apparent.
A phenomenon that is completely opposite to the above-mentioned advantages often occurs. In other words, when automatic control is implemented, it becomes common sense to operate continuously for 24 hours a day for several years.
As a result, the wear of the belt M is significantly shortened, and the sliding parts of the variable pulleys L and N, the bearing parts O and P, etc. are also worn out extremely quickly. In particular, belt M is not carefully monitored by the operator, so it may continue to operate under high load for a long time without noticing, or the input motor may start and stop frequently, or As a result, the frictional heat between the pulley and the belt increases at an accelerated pace, significantly shortening the life of the synthetic resin belt M. Moreover, if the rotation is stopped during high-load operation, the belt M is in principle held in place by a pulley consisting of a fixed and a sliding disc wheel, so the next time the belt is started At times, the high load state on the load side and the starting force on the motor side momentarily cause the belt M to
As a result of this, many accidents occur where the belt M is instantly severed, and this tendency has been exacerbated by the increase in horsepower of transmissions.
The problem becomes more serious as the size of the machine increases, and especially in large models, new belts may break after only being used for a short period of time.

Furthermore, as is clear from the configuration shown in FIG. 5, once the belt M breaks, replacing the belt becomes extremely complicated. In other words, since a heavy load device is normally connected to the output shaft E, the transmission B must be removed from the load device, and then the lid body must be removed.
I ₁ , I ₂ , the left and right side covers J, and the handle cover H are removed, and the belt M is replaced with a new one. Moreover, as a result of removing the bearing O or P from the output shaft E and moving the input and output shafts E and F closer to each other,
Work that was essentially equivalent to disassembling a transmission was to be required on site. Especially when this type of transmission is installed in a dangerous place such as a high place,
Since such maintenance work is virtually impossible, the work must be done on level ground using a crane truck, resulting in significant losses in terms of cost and efficiency.

〔the purpose〕

When completely automating a belt-type transmission, this invention takes measures to suppress belt wear as much as possible, and at the same time, it takes measures to reduce belt wear and tear.
Another object of the present invention is to provide a transmission that has an improved structure that allows for easy belt replacement when belt replacement is necessary due to a cutting accident, etc., and is suitable for automatic control.

[Technical means to solve problems]

In this invention, firstly, in order to control the speed change of the transmission, a pilot controller connected to an adjustment circuit device is removably installed on the outer wall of the housing, and the adjustment circuit device is configured to control the rotation of the input shaft. A start/stop control circuit is provided which forcibly supplies a deceleration output for a predetermined period of time when a stop signal is received, and stops rotation of the input shaft in the maximum deceleration state. Second, the output shaft is equipped with the variable pulley at one free end, and is inserted into the housing chamber from the other flat side of the housing while being supported by the flange in a cantilevered state, and the output shaft is inserted into the housing chamber from the other flat side of the housing. A cover body is provided in front of the free end of the output shaft to expose the variable pulley mounted on the output shaft.

[Effect]

Of these configurations, in the first configuration, a start/stop control circuit is installed in the adjustment circuit device for automatic control, so the belt always rotates from a low speed at startup, so the impact on the belt at startup is light. It's done. Moreover, since the speed is gradually increased until the desired rotation is reached, the load on the belt is significantly reduced.
In addition, if the belt and pulley are normally stopped at a high-speed position, not only will the impact upon startup become significantly large, but also because the belt and pulley are sandwiched between the upper and lower disc wheels with a large spring force. If the belt is started in this condition, the belt will be wound around the pulley in the circumferential direction, which will easily cause damage to the belt itself, but at low speeds the spring pressure is weak, which contributes to extending the life of the belt.

In addition, in the second configuration, the output shaft is supported in a cantilevered manner, and a large opening can be made only around the variable pulley installed at the free end by opening the lid, so that one circle of the pulley can be opened. The belt can be replaced simply by removing the plate wheel or moving the output shaft. This helps speed up the work since there is no need to remove the transmission itself from the load device when replacing the belt, unlike in the past.

〔Example〕

FIG. 1 is a sectional view of a transmission according to an embodiment of the present invention. This transmission 26 includes a frame body 45 and a lid body 46.
A housing 28 is formed, and a sealed chamber is formed to prevent raindrops and moist air from entering. Inside,
A pair of pulley devices 5 each consisting of fixed pulleys 54a, 55a and sliding pulleys 54b, 55b for clamping a speed change belt 53 on an electric motor rotating shaft, that is, an input shaft 51, and an intermediate rotating shaft 52, respectively.
4,55 is installed. Drive side pulley device 5
4 includes an impeller 5 attached to a sliding pulley 54b.
6b and a spiral casing 56a, a part of the casing 56a communicates with the piping 36', and communicates with the inlet piping 36 as shown in the applied example of FIG. 3 to be described later. are doing. Thereby, heat radiation air is forcibly introduced into the room from the outside and is discharged from the outlet 37 provided in the lid 46. Pilot electric controller 29
is connected to the ratio adjustment screw 57, and this adjustment screw 5
7, the guide ring 58 moves up and down, thereby adjusting the distance between the fixed pulley 54a and the sliding pulley 54a and controlling the gear ratio. Reference numeral 49 denotes a well-known coupling which is configured to be detachable when the pilot controller 29 is removed from the housing 28 together with the support frame 48. Note that the pilot controller 29 may be of other known structure,
For example, the bending lever K shown in FIG. 5 may be controlled by a reversible electric motor or the like, and in this case, the pilot controller 29 from the variable pulley may be configured to be detachable from the outer wall of the housing 45.

Now, when the pilot controller 29 is activated and the sliding disc wheel 54b begins to slide accordingly, the radius of contact between the pulley device 54 and the variable belt 53 changes. Even on the driven side, where the belt 53 is simply held by a spring force, the contact radius of the belt 53 changes as the driving pulley 54 changes, and the speed ratio is controlled by this cooperative automatic adjustment. Note that when this type of device structure is installed in a dangerous location such as the top of a building, it is necessary to prioritize maintenance work as much as possible, and in the present invention, the intermediate rotating shaft 52 is The two bearings 59a, 59b
It is supported cantilevered by. Moreover, the structure of the housing 28 is such that the lid body 46 can be separated from the frame body 45, and along with this, the shaft support 6
0 has an adjustment mechanism using a bolt 62 and an elongated hole 61 so that it can be slid with respect to the frame 45. As a result, by loosening the bolt 63 and operating the hoisting bolt 62, both the support body 60 and the pulley can be moved in the direction of the input shaft, thereby simplifying belt replacement. Note that other methods may be used for replacing the belt; for example, the output shaft 52 may be fixed so that it cannot be moved, and only the fixed disc wheel 55 may be removed. Lid body 4 of this housing 28
6 has a D-shaped or horseshoe-shaped upper surface and is opened to a considerable height, so that the side surface of the straight portion of the D-shape is cup-shaped. Therefore, the operation of moving or removing the pulley 55 is expedited.

Next, an adjustment circuit device for fully automatic control when this belt transmission 26 is applied to control the rotation of a blower in a cooling tower or the like will be described.

FIG. 2 is a block circuit connection diagram of an adjustment circuit device for automatically controlling the cooling water temperature of the cooling tower 10. A temperature detector 68 is provided at the cooling water inlet 66 of the cooling tower 10 and is connected to a servo regulator 70 . The servo controller 70 includes a bridge circuit 71 and an operational amplifier 7.
2, a filter 73, an operational amplifier 74, a positive feedback circuit 75, a dead zone circuit 76, and amplification and deceleration side output circuits 77 and 78. The output circuits 77 and 78 are also connected to the pilot controller 29 via their contacts 77a and 78a. The power supply end S' and
T′ is the three-phase power supply line 8 to the main induction motor 27
It is supplied from the S and T terminals of 3. on the other hand,
A start/stop control circuit 80 and a low temperature section control circuit 81 are connected to this power line 83 .

The operation of this regulator is as follows. When the start switch SW is pressed, the relay 3R is operated via the normally closed contact 2R2, and the contact 3R1 is self-held, and the power to the regulator 70 (not shown) is turned on, and the regulator 70 operates, but the pilot control is not activated. The machine 29 does not operate because the contact 4R2 is open. Next, while the temperature of the cooling water is maintained within the proportional operation range of the regulator 70, the mechanical temperature detector 68 for low temperature range control is closed.
The low temperature section control circuit 81 is activated by the closing of the contact 3R1, and at this time, the contact 3R2 is closed and the relay 4 is activated.
R is energized. Therefore, the main blower motor 27 operates via the three contacts 4R1. At the same time, the pilot section 29 is closed by closing the interlock contact 4R2.
operates and performs normal proportional control operation.

At this time, if the outside air wet bulb temperature is constant, the rotation speed of the blower fan will increase as the cooling water temperature rises, but even if the high limit switch HL of the pilot controller 29 is closed, the blower fan will remain at its maximum speed. Run continuously. In this case, the cooling state is determined by the required cooling capacity of the cooling tower, but if the cooling water temperature drops too much and the rotation speed of the blower fan is maintained at a high speed, the cooling water will become supercooled, and the large electric motor of the compressor will It was causing damage. Therefore, when the cooling water temperature drops, even if low limit switch LL is opened and relay 1R is opened, relay 3R is still energized by contact 2R2, so main fan motor 27 continues to rotate. The blower fan 21 rotates at the lowest speed.

At this time, if the cooling water temperature drops further as in winter, the liquid-filled inlet water or outlet water temperature detection sensor 68 or 69 is activated, the relay 4R is deenergized, and the main motor 27 can be stopped. It's becoming like that. That is, when the cooling water temperature is within the proportional band range of the regulator 70, the fan rotation speed is proportionally controlled according to the temperature, and when the temperature falls below the proportional band range, automatic start/stop control of the main motor 27 is performed. It is configured to obtain.

Next, to completely stop the blower, press stop switch SW, energize relay 2R, and contact 2
R1, 2R2 are reversed, and at the same time regulator 70
A contact (not shown) of the bridge circuit 71 is activated to send out a signal that causes only the deceleration output circuit 78 to operate. Then, the pilot controller 29 receives this deceleration command and eventually turns on the low limit switch.
LL opens, relay 1R deenergizes, contact 1R1
is opened, the relay 3R is deenergized, the regulator 70 stops operating, and the relay 4R is further stopped via its contact 3R2. In other words, the start/stop control circuit 8
0 performs slow start control in this way, and when stopped, the belt 53 is stopped at the lowest speed, achieving ease of maintenance, and at the same time, at the next restart, the blower fan is always at the lowest or highest speed. It is started from a light load state. Therefore, especially at the time of starting, not only does auxiliary equipment such as a reactor starter become unnecessary, but the belt of the transmission is also protected, extending the life of the belt and the transmission.

As mentioned above, the transmission of the present invention includes an adjustment circuit device for automatic control, and is realized only when combined with this.Next, we will explain a specific example of the application of this transmission to a cooling tower blower. A layout diagram when applied to is explained below.

In FIG. 1, a partial sectional view of a double suction type cross-flow cooling tower 10 is shown as an embodiment. In the figure, 11 is a water tank, 12 is an air inlet louver, 1
3 is a filler, 14 is an eliminator, 15 is a partition wall, and above these, cooling water is connected to the inlet pipe 1.
7 to the sprinkler channel 16. Further, a cylindrical fan stack 24 is installed in the center, and an air outlet 20 is provided at the top of the fan stack 24, between which a blower fan 21 and a gear reducer 22 are installed in the center of a pipe stay 23 that is radially incorporated. Ru. The configuration of the cooling tower described so far is already known.

Furthermore, the top plate 2 adjacent to the fan stack 24
5 includes an induction motor 27 and a pilot controller 2.
A variable power transmission 26 is installed, which is composed of a variable power transmission 9 and an increase/decelerate type transmission 28 in which an electric motor 27 and a controller 29 are integrally assembled. The rotational output of this transmission is also coupled to the gear reducer 22 by a coupling 30 and a transmission body 31.
In addition, in order to insulate the frictional heat between the belt and the pulley, the transmission 26 circulates the air in the sealed chamber of the transmission 26 from the cooling air inlet 35 through the piping 36, and then
It has a mechanism to prevent the belt from being ejected from the exhaust port 37, and is intended to improve the belt life rate. Further, this speed-up/deceleration type transmission 26 can be adjusted in position in the longitudinal direction by a bolt 38 and in the vertical direction by a plurality of bolts 39, making it easy to align the coupling ring 30. 40 and 41 are wiring for power supply and control signals.

〔Effect of the invention〕

According to this invention, as a measure to protect the belt that occurs when the transmission is completely automatically controlled, firstly, a start/stop control circuit is provided to cause the automatic control adjustment circuit device to start slowly. Therefore, even if start/stop control is repeated, the engine is always started from the lowest speed state, and the instantaneous impact applied to the belt during startup is greatly reduced. As a result, wear of the belt is not accelerated and damage due to bending deformation of the belt does not occur, so that a significant extension of the life of the belt can be achieved.

In addition, when operating continuously for a long time under automatic control,
Belt wear increases significantly and the frequency of belt replacement increases, but belt replacement does not require work such as removing the transmission from the load device and also eliminates the need to disassemble the equipment inside the transmission. Therefore, even a completely unskilled person can complete the replacement work in a short time without requesting a specialist.

Up until now, improving transmissions to be compatible with automatic control has only been used in limited fields where operators are always present, but as shown in this example, Since it has come to be used in blowers, pumps, and various industrial fields, its industrial value is extremely large.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view of a transmission according to an embodiment of the present invention, Fig. 2 is a wiring diagram of an automatic control adjustment circuit device when the same transmission is applied to a blower, and Figs. 3 and 4 are diagrams. Both show external configuration diagrams when the same transmission is applied to a cooling tower blower. Furthermore, FIG. 5 shows a schematic configuration diagram of a conventional belt transmission. In the figure, 10... cooling tower, 21... ventilation fan,
22... Constant speed ratio reducer, 27... Main blower motor,
28...Transmission, 29...Pilot controller, 5
DESCRIPTION OF SYMBOLS 1...Input shaft, 52...Intermediate shaft, 70...Adjustment circuit device, 80...Start/stop control circuit, 81...Low temperature section control circuit.

Claims (1)

[Scope of Claims] 1. A transmission in which an input shaft is taken out from one side of a flat housing consisting of a frame body and a lid body, and an output shaft is taken out from the other side, and each shaft is provided with a variable pulley. A pilot controller connected to an adjustment circuit device is installed in the housing, and when the adjustment circuit device receives a rotation stop signal of the input shaft, it forcibly supplies a deceleration command to the pilot controller to achieve maximum deceleration. The output shaft has a start/stop control circuit for stopping rotation of the input shaft when the input shaft is in the state, and the output shaft is equipped with the variable pulley at the free end and has a flange pivoted in a cantilevered state on the other side of the housing. The single cover is inserted into the frame from the side and is formed in front of the free end of the output shaft for maintenance purposes so that the periphery of the variable pulley mounted on the output shaft can be opened and exposed. A transmission characterized by a decorated body. 2. The lid body is arranged to cover the variable pulley, has a D-shaped top surface, and has an L-shaped front side surface joined to the frame body for sealing. The transmission described in range 1. 3 The housing is sealed indoors, and has a cooling air inlet for heat dissipation in the frame and an outlet in the lid, and a forced draft blower is provided in the air passage from the inlet to the outlet. A transmission according to claim 1, characterized in that: