JPS6332728Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Field of Application) This invention relates to a device for automatically controlling the temperature inside the passenger compartment of a sub-engine-driven bus cooler. (Prior Art) This type of bus cooling system has a compressor connected to the engine, so by changing the engine speed, the compressor speed, ie, the cooling capacity, can be adjusted. For this reason, if the cooling load in the vehicle interior is large, the engine speed will be increased to rapidly cool the vehicle, and conversely, if the cooling load is small, the engine speed will be lowered to reduce the noise and energy generated by engine rotation. It is conceivable to reduce the consumption of air, and at the same time, prevent sudden changes in the temperature of the blown air due to intermittent operation of the compressor. Based on these circumstances, in the past, for example,
Inventions disclosed in No. 34822, No. 53-21782, and Japanese Unexamined Patent Publication No. 119747/1988 have been made. In Japanese Patent Publication No. 50-34822, a servo motor is installed to adjust the engine speed,
It is shown that the output position of this servo motor is continuously adjusted according to the cooling load in the vehicle interior, and the engine speed is controlled steplessly. Further, Japanese Patent Publication No. 53-21782 discloses that the engine speed is controlled in two stages, an upper limit and a lower limit, by operating a thermostat on a motor for adjusting the engine speed. In addition, Tokukai Akira
No. 54-119747 discloses using two solenoid valves to adjust the engine speed, and controlling the engine speed in three stages by controlling the solenoid valves on and off. (Problems to be Solved by the Invention) However, in this conventional example, there was a problem in that the simplicity of the control device and the accuracy of control could not be balanced. In other words, Special Public Interest Publication 1973-
In No. 21782, the engine speed can be controlled steplessly using a servo motor, but in order to deal with disturbances, the control circuit detects, for example, the speed of the fuel injection pump that supplies fuel to the engine. Feedback control must be used to correct the target value by feedback to the comparator of
In the case of JP-A No. 54-119747, the engine speed can be controlled in three stages, but two solenoid valves are required, and although the controllability of both is satisfactory, the configuration of the control device is complicated. However, the problem was that it was expensive. On the other hand, regarding Special Publication No. 53-21782,
The motor rotates forward or backward according to the output of the thermostat, and a switch is provided at the motor stop position to control the motor on and off, so it can be configured with a simple relay sequence. However, if the engine speed is 3
It would have been difficult to move beyond that level. Therefore, the object of this invention is to provide a control device for a bus air conditioner that can control the engine speed in three or more stages and has a simple configuration. (Means for solving the problem) The gist of this invention is to use a motor that adjusts the rotational speed of the engine that drives the compressor, and a control signal that is generated in accordance with the outputs of the temperature setting device and temperature detector. a thermostat that switches the motor into at least three stages; a plurality of relays that select a circuit for energizing the motor according to the output of the thermostat; and a control switch provided in the energization circuit. , sliding contacts provided on both sides of a rotating shaft that rotates together with the motor, and arranged symmetrically around the rotating shaft,
It consists of a plurality of sliding surfaces, each having a predetermined length, and the energizing circuit is opened when the sliding contacts are separated from the sliding surfaces. (Function) Therefore, when a control signal corresponding to the cooling load is output from the thermostat, the relay is activated and the energizing circuit for the motor is selected, and the motor rotates until the control switch opens the energizing circuit. , since the engine speed is controlled,
Although it has a simple configuration similar to the one shown in Publication No. 21782, the control switch is composed of a sliding contact and a corresponding sliding surface, and depending on the shape of this sliding surface, there are three or more stages. It is possible to perform on/off control, and therefore the above-mentioned problem can be achieved. (Example) In FIG. 2, first, an outline of a bus cooling system will be explained. Engine 1 is a sub-engine, for example, a diesel type, which is independent of the driving engine, and is rotated by fuel injected from a fuel injection pump 2. I'm starting to do that. Two compressors 3 and 4 are connected to this engine 1, and the compressors 3 and 4 are connected through piping together with a condenser 5, a liquid tank 6, an expansion valve 7, and an evaporator 8 to form a closed cooling cycle. There is. The evaporator 8 is disposed in a duct 9 together with a fan 10, and as the fan 10 rotates, outside air or inside air sucked into the duct 9 from an inlet 11 passes through the evaporator 8 and is cooled, and is cooled from the air outlet 12 into the vehicle interior. The air is blown out to cool the inside of the vehicle. Said fan 1
0 is connected to the engine 1 and rotates in response to the drive of the engine 1. Further, the amount of fuel injected from the fuel injection pump 2 is adjusted according to the position of a control lever 13, and this control lever 13 is moved by the rotation of an actuator 16 having a motor 15. The rotation speed of the engine 1 is adjusted according to the rotation of the motor 15. Furthermore, the above 2
The two compressors 3, 4 have electromagnetic clutches 3a, 4a, respectively, and the electromagnetic clutches 3a, 4a
Drive and stop are controlled according to the intermittence of In FIG. 1, the electromagnetic clutches 3a, 4a
and an electric circuit for controlling energization to the motor 15. A power line _l1 , one end of which is connected to a power source 17, is connected to a key switch 18 and the key switch 1.
A control switch 19 following 8 is provided, and this control switch 19 has a movable contact 19a and fixed contacts of Lo, Auto, and Hi. The Lo contact of this control switch is not connected anywhere, and the Auto contact is connected to the earth line _L2 via the coils _R1a and _R2a of the automatic control relay. In addition, the Hi contact is connected to the high speed relay coil via diodes 20 and 21.
R _3a and the coils R _4a and R _5a of the medium-speed relay are connected, and the other ends of the coils R _3a , R _4a and R _5a of the relay are connected to the earth line l ₂ . The thermostat 22 has its power terminal connected between the key switch 18 and the control switch 19 of the power line _l1 via the fan switch 24 of the temperature setting device 23 and the fuse 43, and when the fan switch 24 is closed. It is designed to start operating when the The temperature setting device 23 is integrated with a fan switch 24 and a variable resistor 25, and the variable resistor 25 adjusts the temperature of the blown air, for example.
The voltage value can be set in three stages: T ₁ , T ₂ , and T ₃ (T ₁ > T ₂ > T ₃ ). Further, the temperature detector 26 is composed of a thermistor or the like, and is provided at the suction port of the evaporator 8, and detects the temperature t of that portion as a voltage value. The thermostat 22 includes a window comparator 27, a logic circuit 28, and amplifiers 29a to 29d, as shown in FIG. The window comparator 27 includes, for example, three comparators 2
7a to 27c, and the window comparator 27 includes a variable resistor 25 of the temperature setting device 23.
The set temperatures T ₁ , T ₂ , T ₃ from the temperature sensor 26 and the detected temperature t from the temperature detector 26 are inputted, and the two are compared and signals A, B, and C are outputted, and the relationship between them is is as shown in Table 1 below.

[Table] However, each comparator 27a to 27
Since hysteresis is provided in c, the above outputs A, B, and C are reversed at each ON point of the set temperature when the detected temperature t increases, and reversed at each OFF point when the detected temperature t decreases. . The logic circuit 28 includes the window comparator 2
It inputs the outputs B and C of the two comparators 27b and 27c of No. 7, performs a logical operation, and outputs the signals D ₁ and D _2. The signals D ₁ and D ₂ are as shown in Table 2 on the next page. be.

[Table] First, the logic circuit 28 has an internal clock generator, and changes in the output signal occur in synchronization with the output timing of this clock.
n is for displaying the clock output timing, especially when input B = “L” and input C = “H”.
The clock output timing is displayed.
Assuming that inputs B and C are currently "L" and "H", respectively, this clock output timing is set as n (hereinafter referred to as "this time"), and before this n, inputs B and C are
n of the times when were respectively "L" and "H"
The time nearest to is called nm (hereinafter referred to as "previous time"). )
It is said that Therefore, D _1o is input B=“L” and input C=
It means the output signal of the logic circuit 28 at the clock output timing n which was "H". For example, if we consider the current output signal when both inputs B and C once become "L" between clock output timing n and nm, the previous output
If D _1o-n and D _2o-n are “L” and “H”,
When inputs B and C change from “L” and “L” to “L” and “H”, the previous outputs “L” and “H” are reversed and become “H” and “L”. . The output A is amplified via the amplifier 29a and output from the output line _l3 , the output B is amplified via the amplifier 29b and output from the output line _l4 , and the output _D1 is amplified via the amplifier 29c and output. From the lines l ₅ and l ₆ , the output D ₂ is amplified via the amplifier 29d and sent to the output line
It is designed to be output from l ₇ and l ₈ respectively. The output lines l ₃ and l ₄ are connected to the diodes 20 and 2.
1 and the coil R3a of the high-speed relay and the coil R4a of the medium-speed relay through normally open contacts R _1b and R _1c of the automatic control relay. Also,
The output lines _l5 , _l6 , _l7 , _l8 are connected to the electromagnetic clutches 3a,
It is connected to the earth line _l2 via the coil 4a or indicator lamps 30, 31. Furthermore, the output line l ₆ ,
l ₇ is the diode 32, 33 that constitutes the OR circuit.
and the normally open contact R _2b of the automatic control relay to the coil R _6a of the low-speed relay, and the other end of the coil R _6a of the low-speed relay is connected to the earth line l ₂ . The actuator 16 is configured to be powered on via the fuse 34 without passing through the key switch 18, and is provided with a plurality of energizing circuits for energizing the motor 15, and the energizing circuits include: When the normally open contact R _3b of the high-speed relay and the coil R _4a of the medium-speed relay are de-energized, on the power supply side,
Contacts R _4b of the medium-speed relay are connected to the ground side when energized, respectively connected to the ground side when the coil R _5a of the medium-speed relay is de-energized, and connected to the power supply side when energized. contact point
R _5b and a normally closed contact R _6b of a low speed relay are interposed. Further, the energizing circuit includes the motor 15.
A control switch 35 is provided for stopping the motor at Lo, Me, and Hi stop positions. This control switch 35 operates around a rotating shaft 36 that rotates together with the motor 15.
Sliding contacts 37a and 37b are fixed on both sides of 6. The sliding contacts 37a, 37b are mutually non-conductive, and each has three contact portions that are mutually conductive. Moreover, the sliding contact 37a,
Sliding surfaces 38a to 38c and 39 correspond to 37b.
a to 39c are provided. The sliding surface 38a~
38c and the sliding surfaces 39a to 39c are vertically symmetrical with respect to the rotating shaft 36, each having an arc shape and a predetermined length in the circumferential direction. The longest, the sliding surfaces 38c, 39c are the shortest, the sliding surfaces 38b, 3
9b is in between. And sliding surface 3
8a is connected to the contact R _4b of the medium speed relay and the other sliding surface 39a, the sliding surface 38b is connected to the diode 40 in the opposite direction to the normally open contact R _3b , and the sliding surface 38c is connected to the diode 40 in the opposite direction to the normally open contact R 3b. diode 40 on the sliding surface 3
9b is the normally closed contact R _6b and the forward diode 4
1, the sliding surface 39c is connected to the positive terminal of the motor 15 via the same diode 41, and the negative terminal of this motor 15 is connected to the contact point.
This is the one connected to R _5b . In the above configuration, first, the state in which the key switch 18 is open will be explained. Since the key switch 18 is open, the engine 1 is naturally not driven, but power can be directly applied to the actuator 16 without passing through the key switch 18. It's becoming like that. On the other hand, in this situation,
Since the coils R _3a , R _4a , R _5a , and R _6a of the relay are de-energized, the corresponding contacts R _3b ,
R _4b , R _5b , and R _6b are as shown in FIG. Therefore, even if the engine 1 stopped at high speed last time (the sliding contacts 37a and 37b stopped at the Hi position), the contact R _4b and the sliding surface 38
A, 39a, the sliding contact 37b, the sliding surface 39b, the contact R _6b , the diode 41, the motor 15, and the contact R _5b are established. It rotates forward until it reaches the position and then stops. Therefore, the engine 1 always starts at a low rotation speed. Next, a blowing operation in which only air is sent will be described. In this case, the key switch 18 is closed to drive the engine 1, but the fan switch 24 is left open and the power to the thermostat 22 is cut off. At this time, control switch 1
When 9 is set to Lo, the automatic control relay coils R _1a and R _2a are not energized and are de-energized.
The corresponding contacts R _1b , R _1c , and R _2b are opened, and the coils R _3a , R _4a , R _5a , and R _6a of the relay are not energized and remain de-energized. The corresponding contacts R _3b , R _4b , R _5b , and R _6b are arranged as shown in FIG. D ₁ and D ₂ are all “L”
It is becoming. Therefore, the engine 1 rotates at a low speed, the electromagnetic clutches 3a, 4a are de-energized, and the compressors 3, 4 are not driven.
Only the fan 10 rotates at a low speed, and the air sucked into the duct 9 from the suction port 11 is blown out from the blow-off port 12 with a small amount of air without being cooled. Next, when the control switch 19 is set to Auto, the coils R _1a and R _2a of the automatic control relay are energized, and the coils R _1a and R _2a are excited, and the corresponding contacts R _1b , R _1c , and R _{2b are} energized. is closed, but since power to the thermostat 22 is cut off, only the fan 10 similarly rotates at a low speed. Next, when the control switch 19 is set to Hi, the coils R 3a , R 4a , and R 5a of the relay are energized via the diodes 20 and 21, and the coils R _3a , R _4a , and R _5a are energized.
Since R _3a , R _4a , and R _5a are excited, the corresponding contact R _3b is closed, and the contact R _4b is connected to the ground side and the contact R _5b is connected to the power source side. Therefore, the contact R _5b , the motor 15, the diode 4
0, the contact R _3b , sliding surface 38b, sliding contact 37
Since a current-carrying circuit including the sliding surface 38a and the contact _R4b is established, the motor 15 rotates in reverse and stops when the sliding contacts 37a and 37b reach the Hi position.
Therefore, since the engine 1 rotates at a high speed, the fan 10 also rotates at a high speed, and the amount of air into the vehicle compartment becomes maximum. Next, the cooling operation will be explained. In this case, the fan switch 24 of the temperature setting device 23 is closed and the thermostat 22 is energized. At this time,
When control switch 19 is set to Lo,
Coils R _1a and R _2a of the automatic control relay are not energized and are not energized, so the corresponding contacts
R _1b , R _1c , R _2b are opened and the coil of said relay
Since R _3a , R _4a , R _5a , and R _6a are not energized and de-energized, the corresponding contacts R _3b , R _4b , R _5b , and R _6b
is in the state shown in FIG. 1, and therefore the engine 1 rotates at a low speed. On the other hand, since the thermostat 22 is operating at this time, the temperature setting device 23
The outputs D ₁ and D ₂ of the thermostat 22 change as shown in Table 2 according to the set temperatures T ₁ , T ₂ , T ₃ from the variable resistor 25 and the detected temperature t from the temperature detector 26 . Therefore, the detected temperature t and the set temperature T ₁ ,
When the difference between T ₂ and T ₃ is large, the electromagnetic clutches 3a and 4a are energized via the output lines l ₆ and l ₇ , and the two compressors 3 and 4 are driven, and the output line
The indicator lamps 30, 31 are energized via _l5 , _l8 . When the temperature difference between the two becomes smaller, only one of the compressors 3 and 4 is driven, and one of the indicator lamps 30 or 31 lights up, and furthermore,
When the temperature difference between the two becomes small, both compressors 3 and 4 stop, and both indicator lamps 3 turn off.
0 and 31 disappear, but alternate when one of the compressors 3 and 4 is operated. Next, when the control switch 19 is set to Auto, the coils R _1a and R _2a of the automatic control relay are energized and the coils R _1a and R _2a are excited.
The corresponding contacts R _1b , R _1c , R _2b are closed, and therefore the rotational speed of the engine 1 and the compressors 3 and 4 are
The number of drive bases is controlled by the output of the thermo switch 22. That is, as shown in FIG. 4a, for example, the variable resistor 25 of the temperature setting device 23 is set to T ₃
If the detected temperature t of the temperature detector 26 starts from a temperature _S1 higher than the set temperature _T1 ,
As shown in Tables 1 and 2 above, thermostat 2
2 outputs A to D ₁ , D ₂ all become "H", and therefore the coils R _3a , R _4a , R _5a ,
When R _6a is energized, the coils R _3a , R _4a , R _5a , and R _6a are energized, the corresponding contact R _3b is closed, and the contact R _6b is energized.
is open, contact R _4b is connected to the ground side, and contact R _5b is connected to the power supply side. Therefore, an energizing circuit including the contact R _5b , the motor 15, the diode 40, the contact R _3b , the sliding surface 38b, the sliding contact 37a, the sliding surface 38a, and the contact R _4b is established, so that the motor 15 is reversed, and the sliding contacts 37a,
When 37b reaches the Hi position, it stops and engine 1
begins to rotate at high speed. On the other hand, as in the case described above, the electromagnetic clutches 3a and 4a are energized to drive both the compressors 3 and 4, so that they are operated at the highest cooling capacity. Then, the detected temperature t gradually decreases to reach the set temperature.
When the off point of _T1 is reached, the output A of the thermostat 22 is reversed to "L", so the current to the coil _R3a of the high speed relay is cut off, and its contact _R3b is opened. Moving contacts 37a, 37b
is in the Hi position, the motor 15 is not energized, and therefore the rotational speed of the engine 1 remains high and does not change. In this state, even if the detected temperature t again exceeds the ON point of the set temperature _T1 and then falls below the OFF point, the high speed relay is simply turned on and off and there is no change in the operating state. Next, when the detected temperature t falls to the off point of the set temperature _T2 , the output B of the thermostat 22 becomes "H".
Since it reverses from “L” to “L”, the medium speed relay coil
The current supply to R _4a and R _5a is cut off, and the coils R _4a and
R _5a is demagnetized, contact R _4b is connected to the power supply side, and contact R _5b is connected to the ground side, so the contact
R _4b , sliding surfaces 38a, 39a, sliding contact 37b,
An energizing circuit including the sliding surface 39c, the diode 41, the motor 15, and the contact _R5b is established, and the motor 1
5 rotates normally until the sliding contacts 37a and 37b come to the Me position, stops at that position, and starts rotating at a medium speed. In addition, the output of thermostat 22
Since _D1 becomes "L", the power to the electromagnetic clutch 3a is cut off and one compressor 3 stops. Next, when the detected temperature t again exceeds the ON point of the set temperature _T2 , the output B of the thermostat 22 becomes "L".
to “H”, medium speed relay coil R _4a ,
R _5a is energized and excited, its contact R _4b is connected to the ground side, and its contact R _5b is connected to the power supply side.
The energizing circuit for the motor 15 is not formed, and therefore,
Engine 1 remains at medium speed. Meanwhile, the compressor 3 starts to be driven again, and two compressors are now operated. Then, when the temperature falls below the off point of the set temperature _T2 again, one compressor 3 stops. When the detected temperature t further decreases to below the off point of the set temperature _T3 , the output A of the thermostat 22
~D ₁ and D ₂ are all “L”, so the current flow to the coils R _3a , R _4a , R _5a , and R _6a of the relay is cut off, and the coils R _3a , R _4a , R _5a , and R _6a is demagnetized and the corresponding contacts R _3b , _{R 4b} , R _5b , R _6b become as shown in FIG. Moving surface 39
A current-carrying circuit including contact R _6b , diode 41, motor 15, and contact R _5b is established, and motor 1
5 rotates normally until the sliding contacts 37a and 37b come to the Lo position, the engine 1 rotates at low speed, and both compressors 3 and 4 stop. Then, when the detected temperature t rises or falls above or below the on point and off point of the set temperature _T3 , the compressor 3 is turned on and off, but when the detected temperature t exceeds the on point of the set temperature _T3 , the other compressor 4 is activated. However, the subsequent control over changes in the detected temperature t is the same as shown in the figure, except that the other compressor 4 is mainly turned on and off. Note that the detected temperature t of the temperature detector 26 is the set temperature.
If we start from a temperature S ₂ between T ₁ and T ₂ , then
First, the contact R _5b , motor 15, diode 4
0, sliding surface 38c, sliding contact 37a, sliding surface 38
a. Since the current-carrying circuit including the contact point R _4b is established, the engine 1 starts to rotate at a medium speed from the beginning, as shown in FIG. 4b. In the above embodiment, the rotational speed of the engine 1 is switched in three stages, but the switching of the thermostat 22, the energizing circuit and the control switch 3
By increasing the number of sliding surfaces (5), it is possible to perform control in four or more stages. (Effects of the invention) As described above, according to this invention, a control switch is composed of a sliding contact and a sliding surface, and the sliding surface is cut to an appropriate length and arranged in a symmetrical shape. Since this control switch is combined with a thermostat and a relay to form a control device, it is simple and inexpensive, and the cooling capacity can be switched to three or more stages, providing excellent controllability. can be provided.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing a control device for a bus air conditioner according to an embodiment of this invention, Fig. 2 is a block diagram showing an outline of the bus air conditioner, and Fig. 3 is an electric circuit diagram showing a control device for a bus air conditioner according to an embodiment of this invention. FIG. 4 is a block diagram showing the thermostat, and an operation chart showing an example of the operation of the above control device. 1... Engine, 3, 4... Compressor, 1
5...Motor, 22...Thermostat, 23...
... Temperature setting device, 26 ... Temperature detector, 35 ... Control switch, 36 ... Rotating shaft, 37a, 37b ...
...Sliding contacts, 38a-38c, 39a-39c...
…Sliding surface, R _3a … High-speed relay coil, R _3b …
...same contact, R _4a , R _5a ... medium speed relay coil,
R _4b , R _5b ... Same contact, R _6a ... Low speed relay coil, R _6b ... Same contact.

Claims (1)

[Scope of utility model registration request] A motor that adjusts the rotation speed of the engine that drives the compressor, a thermostat that switches control signals in at least three stages according to the outputs of the temperature setting device and the temperature detector, and a thermostat that controls the motor according to the output of the thermostat. a plurality of relays for selecting an energizing circuit; and a control switch provided in the energizing circuit; the control switch includes sliding contacts provided on both sides of a rotating shaft that rotates together with the motor; It is characterized by comprising a plurality of sliding surfaces arranged symmetrically around an axis and each having a predetermined length, and the energizing circuit is opened when the sliding contact is separated from the sliding surface. A control device for a bus air conditioner.