Air conditioner

Abstract: A rotational speed of a fan is maintained at a preset one when an angle of a flap is at a maximum air-flow angle (A°), increased by a specified value when the angle of the flap has been changed by a specified angle in the direction away from the position of the maximum air-flow angle (A°), and decreased by a specified value when the angle of the flap has been changed by a specified angle in the direction toward the position of the maximum air-flow angle (A°). It is possible to prevent any occurrence of condensations and air-flow pulsating noise without needing any complex control such as load response control and yet without requiring any complicate construction in the flap.

Description: The present invention relates to an air conditioner adapted to control the rotational speed, i.e. the number of rotations per unit time of a fan depending on an angle of a flap provided to an air outlet. Air conditioners conventionally available and according to the preamble of the claim known from Japanese Utility Model Application Laid-open publication 1-153441 include one in which a horizontal or vertical flap is provided to an air outlet, the flap being controlled by a stepping motor to thereby change the direction of air blown out through the air outlet. This conventional type of air conditioner has been arranged so that a control of an angle of the flap and that of a fan are carried out independently of each other. Of such conventional air conditioners, one adapted to control the rotational speed of the fan to a constant has been suffered from the following problems. That is, the amount of air flow will increase or decrease depending on change in blowing resistance due to change in the angle of the flap; there may in turn occur condensations of vapor to the flap or the like; thus there may occur a need of some constructional change in the shape of the flap and the like to prevent occurrence of the condensations, which causes the number of design manhours or mold cost to increase. In another air conditioner of the conventional type in which rotational speed of a fan is changed depending on a load to thereby control the amount of air flow to a constant, there have been problems such as described below. That is, since the number of rotations of the fan per unit time will normally vary owing to a change in blowing resistance due to a change in the angle of the flap, there occurs pulsating noise in accompaniment to air flow; a great number of manhours are involved in tests for determining constants necessary for load response control; or, printed circuit boards must be increased in number for accommodating circuit components to meet the constants. An air conditioning apparatus is also known from US-A-36 84 170 and includes a heat exchanger and a fan arranged to route air to be treated over the heat exchanger through an air outlet. The fan speed is increased in this known apparatus as the flap is moved to increase the area of the discharge opening such that the discharge velocity/static pressure of the air is maintained roughly constant. A heat pump type air conditioner is also known from JP-A-600 091 152 in which the control between the fan speed and flap angle of the air conditioner is controlled at the start-up phase such that the flap angle is coincidentally reduced when the fan speed is increased. In normal operation, the flap angle is controlled in dependence on the temperature requirement. The object of the present invention is therefore to provide an air conditioner capable of preventing any occurrence of condensations of vapour and air-blow pulsating noise without the need of any complex control such as load response control and yet without any constructional change in the shape of a flap or the like. In order to achieve the aforementioned object, the present invention provides an air conditioner according to claim 1. The angle change calculation means, upon receiving a signal from the angle control means for controlling the angle of the flap provided to the air outlet, calculates the direction and amount of a change in the angle of the flap. Then the rotational speed control means, upon receiving the calculation result of the angle change calculation means, either maintains the rotational speed of the fan at a preset one when the angle of the flap is a maximum air-flow angle at which the amount of air blown out through the air outlet is a maximum, or increases the rotational speed of the fan by a specified value when the angle of the flap has changed by a specified angle in the direction away from the position of the maximum air-flow angle, or decreases the rotational speed of the fan by a specified value when the angle of the flap has changed by a specified angle in the direction toward the position of the maximum air-flow angle. In this way the rotational speed of the fan is controlled depending on the angle of the flap, which allows the control to be simplified, while it is further possible to prevent the occurrence of condensations and air-flow pulsating noise by properly setting the control range of the rotational speed of the fan. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: Fig. 1 is a schematic block diagram of a main part of an embodiment of an air conditioner of the present invention; Fig. 2 is a view for explaining a variation of an angle of a flap from a maximum air-flow angle; and Fig. 3 is a flowchart showing a control of the same embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now the present invention is described in more detail with reference to the embodiment illustrated by the accompanying drawings. Fig. 1 is a block diagram of a main part of an embodiment of the present invention. A reference numeral 1 stands for a remote controller, 2 for a microcomputer, 3 and 4 for controllers, 5 for a stepping motor for driving a flap (horizontal blade) provided to an air outlet, and 6 for a fan motor for feeding air heat-exchanged by a heat exchanger in the air outlet. The flap, the air outlet and the heat exchanger are not shown in the drawings, as they are well-known. The microcomputer 2 is provided with an angle control means 2a for controlling the rotational angle of the stepping motor 5 (i.e. the angle of the flap) via the controller 3, an angle change calculation means 2b for calculating the direction and amount of a change in the angle of the flap upon receiving a signal from the angle control means 2a, and a rotational speed control means 2c for controlling the rotational speed of the fan motor 6 via the controller 4. The rotational speed control means 2c makes the fan motor 6 rotate at a number of rotations per unit time set by the remote controller 1 or by air-flow automatic control via the controller 4. The angle control means 2a, on the other hand, makes the stepping motor 5 rotate via the controller 3 upon receiving an auto swing instruction from the remote controller 1, so that the flap swings, thereby changing the direction of air blown out through the air outlet. The flap, as shown in Fig. 2, swings between the angle of 0° and the lower limit angle, an air flow reaching its maximum at a maximum air-flow angle (A°), which is the position of a minimum static pressure. When the flap is made to swing with the rotational speed of the fan motor 6 maintained at the above-noted set one, the amount of air flow will change depending on change in blowing resistance, which leads to occurrence of condensations of vapor to the flap and others. On this account, the angle change calculation means 2b calculates the change and its amount in the angle of the flap and then, based on the calculation result, the rotational speed control means 2c in turn makes the rotational speed of the fan motor 6 change depending on the angle (X°) of the flap (i.e. rotating position of the stepping motor 5) in a manner as described below, so that any condensation is prevented. Changing the rotational speed of the fan motor 6 will be effected as follows: (i) If 0≤X<A: (1) The rotational speed of the fan will be changed by -ΔWα each time the flap has moved in the forward direction by Δα°; and (2) The rotational speed of the fan will be changed by +ΔWα each time the flap has moved in the reverse direction by Δα°. (ii) If A<X≤Lower limit: (1) The rotational speed of the fan will be changed by +ΔWβ each time the flap has moved in the forward direction by Δβ°; and (2) The rotational speed of the fan will be changed by -Δwβ each time the flap has moved in the reverse direction by Δβ°. Where, the rotational speed of the fan (W') is assumed to be the minimum at the set rotational speed (W). Thus the result will be: W' = W + ΣΔW (ΔW: ±ΔWα, ±ΔWβ) W' ≥ W In addition, the range of change in the rotational speed of the fan is assumed to be one in which any variation in the air-flow noise can be suppressed, so that there will not occur any air-flow pulsating noise. The controlling operation of the present embodiment is explained hereinbelow according to the flowchart in Fig. 3. At step S1, the angle control means 2a decides whether or not an auto swing instruction has been issued from the remote controller 1. When it has, the angle control means 2a controls the stepping motor 5 via the controller 3 so that the flap automatically swings while it outputs a signal representing a swing angle to the angle change calculation means 2b. Based on the signal from the angle control means 2a, the angle change calculation means 2b calculates the direction and amount of change in the angle of the flap. Next, at step S2, the rotational speed control means 2c determines the swing direction of the flap, based on the calculation result of the angle change calculation means 2b while it determines whether the angle of the flap is above or below A°. Subsequently at Step S3, it is decided whether or not there has occurred a change of Δα° or Δβ° in the swing angle. Then if there has occurred such a change, the operation goes to step S4, where according to the procedures (i) and (ii) with the position of the flap and the change in the swing angle incorporated thereinto, the currently running rotational speed W' of the fan motor by ΔWα or ΔWβ is increased or decreased to yield a new W'. At step S5 it is decided whether or not this new W' is less than the set rotational speed (W). If W'>W, the operation goes to step S6 as it is, where the rotational speed of the fan motor 6 is changed to W'; if W'≤W, then the relation W'=W is accomplished at step S9 and thereafter step S6 succeeds, where the rotational speed of the fan motor 6 is changed to the very W'. At the following step S7, it is decided whether or not an auto swing halt instruction has been issued from the remote controller 1. If it has not, the operation returns to step S2, where the foregoing operation is repeated; if it has, the operation goes to step S8, where the rotational speed of the fan motor is maintained at the currently running rotational speed. In this way the rotational speed of the fan is increased or decreased depending on the amount of change in the angle of the flap from the maximum air-flow angle, so that the amount of air blown out through the air outlet will not be changed to any large extent. Thus, it is possible to prevent any occurrence of condensations without changing the construction of the flap shape and the like. Also, it is possible to suppress any occurrence of air-blow pulsating noise by properly setting the control range of the rotational speed of the fan. Furthermore, the resulting content of the control is simpler than that of load response control, and thus the number of manhours required for a test for determining constants can be reduced while the resulting circuitry can be simplified. As apparent from the foregoing description, the air conditioner of the present invention comprises: an angle change calculation means for, upon receiving a signal from an angle control means for controlling an angle of a flap provided to an air outlet, calculating the direction and amount of a change in the angle of the flap; and a rotational speed control means for, upon receiving the calculation result of the angle change calculation means, maintaining the rotational speed of the fan at a preset one when the angle of the flap is a maximum air-flow angle at which the amount of air blown out through the air outlet is at a maximum, increasing the rotational speed of the fan by a specified value when the angle of the flap has changed by a specified angle in the direction away from the position of the maximum air-flow angle, and decreasing the rotational speed of the fan by a specified value when the angle of the flap has changed by a specified angle in the direction toward the position of the maximum air-flow angle. Thus, it is possible to prevent any occurrence of condensations and air-flow pulsating noise, to reduce the number of manhours and the material cost owing to the fact that no complicate construction is required, and to allow the total cost to be reduced to a substantial extent by reducing the number of manhours for the test for determining the constants and by reducing circuit components owing to the fact that no complex control is required.

Claims: An air conditioner in which air heat-exchanged by a heat exchanger is fed in an air outlet by a fan, and an angle of a flap provided to the air outlet is controlled by an angle control means (2a) to thereby change a direction of air blown out through the air outlet, the air conditioner characterized by comprising: an angle change calculation means (2b) for calculating a direction and amount of a change in the angle of the flap upon receiving a signal from the angle control means (2a); and a rotational speed control means (2c) for, upon receiving calculation result of the angle change calculation means (2b), maintaining a rotational speed of the fan at a preset one when the angle of the flap is a maximum air-flow angle at which an amount of air blown out through the air outlet is at a maximum, increasing the rotational speed of the fan by a specified value when the angle of the flap has changed by a specified angle in a direction away from a position of the maximum air-flow angle, and decreasing the rotational speed of the fan by a specified value when the angle of the flap has changed by a specified angle in a direction toward the position of the maximum air-flow angle, such that the amount of air blown out through the air outlet is not substantially changed.

Inventors: FUKUSHIMA YOSHIMITSU C O SHIGA, KATSUYAMA HIROYOSHI C O SHIGA-, KIZAWA TOSHIHIRO C O SHIGA-SEI, MAKINO ISAMU C O SHIGA-SEISAKU, YAMADA TOSHIYUKI C O SHIGA-SEI, FUKUSHIMA, YOSHIMITSU, C/O SHIGA-SEISAKUSHO OF, KATSUYAMA, HIROYOSHI, C/O SHIGA-SEISAKUSHO OF, KIZAWA, TOSHIHIRO, C/O SHIGA-SEISAKUSHO OF, MAKINO, ISAMU, C/O SHIGA-SEISAKUSHO OF, YAMADA, TOSHIYUKI, C/O SHIGA-SEISAKUSHO OF
Applicants: DAIKIN IND LTD, DAIKIN INDUSTRIES, LTD.
Application year: 1992
Main classification: F24F11
IPC codes: F24F11, F24F13