JPH11136925A - Stepping motor type driver and flow rate control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate control valve and a stepping motor type driver by which a fail-safe operation can be realized at a lower cost. SOLUTION: A drive rod 16 which drives a valve unit 8 is screwed into the rotor 14 of a 4-phase winding 2-phase excitation unipolar drive type stepping motor 3, and the open/close operation of the valve unit 8 is driven by the rotation of the rotor 14. The distortion angle of screws which are formed on the inner circumference of the rotor 14 and on the outer circumference of the drive rod 16 are so predetermined as to generate a rotation force in the rotor 14, when a force in an axial direction is applied to the drive rod 16. A coil spring 17 is provided between a bottom 2c of a valve body 2 and a diaphragm 5 for applying an assisting force for the rotation to move the valve unit 8 in an opening direction to the rotor 14 consistently. Even if one of a pair of coils 12a and 12b which are 2-phase winding coils respectively is open-circuited, the valve unit 8 can be moved in the opening direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor type driving device and a flow control valve.

[0002]

2. Description of the Related Art Heretofore, there has been known a flow control valve which drives a valve body using a stepping motor as an actuator. FIG. 6 shows an example of such a flow control valve (see Japanese Patent No. 2573870).

That is, the flow control valve 51 constitutes a cooling water flow control device for an internal combustion engine. The main body 52 has an inlet side passage 53 communicating with a radiator and a suction passage communicating with a water pump. A valve chamber 56 is provided for joining the bypass chamber 54 and a bypass passage 55 communicating with the water jacket. In the valve chamber 56, a valve body 57 that opens and closes the opening of the inlet-side passage 53 and the bypass passage 55 in a state opposite to each other is housed. The valve body 57 is screwed to the rotor 59 of the stepping motor 58, and is attached to the tip of a drive shaft 61 that reciprocates in the axial direction with the forward and reverse rotation of the rotor 59 when the coil 60 is energized.

In the flow control valve 51, when an output signal corresponding to the operating state of the engine is applied to the coil 60 of the stepping motor 58 to control the rotation direction and the rotation amount of the rotor 59, the inlet side passage 53 The ratio of the circulating amount of the cooling water to the suction passage 54 in the cooling water on the side and the cooling water on the bypass passage 55 can be variably controlled.

In the flow control valve 51, if the coil 60 of the stepping motor 58 breaks while the valve body 57 fully closes the inflow side passage 53, the internal pressure on the inflow side passage 53 side (radiator side) is reduced. It will rise excessively. Therefore, the valve body 57 is urged to the closed position by the spring 62 while the valve body 57 is
When the internal pressure on the inflow side passage 53 side (radiator side) becomes abnormally high with the valve fully closed, the inner side moves to the open position against the bias of the spring 62 and the pressure of the inflow side passage 53 is reduced to the suction passage 54 side. A sub-valve 63 is provided for escape to the side. This enables a fail-safe operation when the coil 60 is disconnected.

[0006]

However, although the above-described flow control valve 51 can perform a fail-safe operation, it requires the sub-valve body 63 in the valve body 57, so that the number of parts is reduced accordingly. In many cases, this is a factor that increases the manufacturing cost of the flow control valve 51.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a flow control valve and a stepping motor type driving device capable of realizing a fail-safe operation at a lower cost. I do.

[0008]

According to the first aspect of the present invention, the object is solved by the rotating force of a rotor of a stepping motor which is generated when a plurality of coils are energized alternately. In the stepping motor type driving device to be driven, an auxiliary force supply means for constantly supplying an auxiliary force when the rotor rotates in one determined direction is provided.

In such a configuration, when a disconnection occurs in any one of the plurality of coils in the stepping motor, the magnetic force generated by the excitation of the non-disconnected coil;
The rotor is rotated in one determined direction by the auxiliary force supplied from the auxiliary force supply means. Therefore, even when a disconnection occurs in any of the plurality of coils, the object can be driven in one direction corresponding to the determined rotation direction of the rotor.

According to the second aspect of the present invention, the flow rate control for controlling the flow rate of the fluid by driving the valve body to open and close by the rotational force of the rotor of the stepping motor, which is generated by alternately energizing the plurality of coils. The valve includes an auxiliary force supply unit that constantly supplies an auxiliary force when the rotor rotates in one determined direction to the rotor via the valve body.

In such a configuration, when a disconnection occurs in any one of the plurality of coils in the stepping motor, a magnetic force generated due to the excitation of the unbroken coil;
The rotor is rotated in one determined direction by the auxiliary force supplied from the auxiliary force supply means. For this reason, the valve element can be driven to either the open position or the closed position corresponding to the determined rotation direction of the rotor.

According to the third aspect of the present invention, the flow rate control for controlling the flow rate of the fluid by driving the valve body to open and close by the rotational force of the rotor of the stepping motor generated by alternately energizing the plurality of coils. The valve is provided with a flow path configuration for constantly generating an assisting force when the rotor rotates in a predetermined direction in the valve body by the pressure of the fluid.

In this configuration, when a disconnection occurs in any one of the plurality of coils in the stepping motor, a magnetic force generated due to the excitation of the unbroken coil;
The rotor is rotated in one determined direction by the auxiliary force based on the fluid pressure generated in the valve body. For this reason, the valve element can be driven to either the open position or the closed position corresponding to the determined rotation direction of the rotor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are views showing a flow control valve 1 of the present invention used in a cooling water flow control device for controlling the amount of cooling water circulating between a radiator and an engine (water jacket) in an internal combustion engine. .

The flow control valve 1 includes a cylindrical valve body 2 and a stepping motor 3 which is an actuator integrally provided at one end thereof. The valve body 2 forms a valve chamber 4 that is open toward the other end, and an inlet 4a that communicates with the engine (water jacket) side is provided in a radial peripheral wall 2a. An annular flange 2b projecting inward is formed integrally with an end edge of the peripheral wall 2a of the valve body 2, and the other end of the valve body 2 communicates with the radiator side by the flange 2b. An outlet 4b is formed.

A diaphragm 5 is provided in the valve chamber 4 at a position retracted to one end side from the inflow port 4a. The diaphragm 5 has a flexible thin rubber member 6 whose outer peripheral edge is pinched and fixed to the peripheral wall 2a of the valve body 2, and a disk-shaped retainer 7 fixed to the front and back surfaces, respectively. It is configured. A valve element 8 is fixed to the center of the front surface of the diaphragm 5 at the outlet 4b side. The valve body 8 is formed based on a metal material such as aluminum or iron so that flexibility is ensured and the surface is covered with a rubber material. The valve body 8 has a bottomed cylindrical mounting portion 8a fixed to the diaphragm, and a pot-shaped valve portion 8b integrally formed on the opening side and opening and closing the outlet 4b from outside. ing.

The stepping motor 3 is of a four-phase winding two-phase excitation unipolar drive type, and comprises a casing 10 connected to the valve body 2, a pair of coils 12a and 12b wound around a bobbin 11, and a bobbin 11 And a pair of stators 13a and 13b which are fitted inside the pair. A rotor 14 is rotatably fitted in the pair of stators 13a, 13b, and both ends thereof are supported by bearings 15, 15.

FIG. 3 is a schematic diagram showing a specific structure of the first and second coils 12a and 12b. One of the coils 12a and 12b has a first terminal # 1 and a common terminal C1 as connection terminals. And a second coil 22 composed of a second coil 22 having the common terminal C1 and the third terminal # 3 as connection terminals, and the other side has a second terminal # 2 and another common terminal C2. Is a two-phase wound coil including a third coil 23 having a connection terminal as a connection terminal, and a fourth coil 24 having another common terminal C2 and a fourth terminal # 4 as a connection terminal. One side of the pair of stators 13a and 13b includes a first stator A and a second stator B located inside one side of the pair of two-phase wound coils 12a and 12b. The other side of 13a, 13b is a pair of two-phase coil 1
It comprises a third stator C and a fourth stator D located inside the other side of 2a, 12b.

The first and second stators A and B, which form a pair, each have a plurality of mountain-shaped teeth arranged in the circumferential direction, and both of the plurality of teeth have a magnetic gap. It is a meshed structure, and the third
The fourth stators C and D have the same structure. The rotor 14 is formed by permanent magnets having different polarities alternately magnetized in the circumferential direction, as shown in the figure. Then, the above-described first to fourth coils 2
1 to 24 are excited in a predetermined order, and the first to fourth
By sequentially switching the magnetic polarities of the stators A to D, a strong rotational force is generated in the rotor 14. FIG. 4 is a diagram showing the polarities of the two stators and the rotor 14 when the two stators and the rotor 14 adjacent to each other in the axial direction are developed in the rotational direction and the rotor 14 rotates. Arrows indicate a suction force and a repulsion force acting on the rotor 14.

On the other hand, a driving rod 16 is screwed to the axial center portion of the rotor 14 in a state where rotation thereof is prevented. The driving rod 16 moves forward and backward in the axial direction as the rotor 14 rotates forward and backward. It has become. The end of the drive rod 16 extending from the rotor 14 is connected to the center of the diaphragm 5 and the valve body 8, and the valve body 8 is moved to the fully closed position (FIG. 1) according to the amount of movement of the drive rod 16. 2) from the fully open position (the position in FIG. 2) to change the opening of the outlet 4b.

The screw A provided on the inner and outer circumferences of the rotor 14 and the drive rod 16 is a multi-threaded screw, and the torsion angle of the screw A causes the rotor 14 to have a rotational force when an axial force is applied to the drive rod 16. Is set to the angle at which Further, between the bottom 2c of the valve body 2 and the back side of the diaphragm 5, a coil spring 17, which is an auxiliary force supply means of the present invention, is contracted. This allows
The diaphragm 5 is constantly urged toward the outflow port 4b, and the rotor 14 is constantly supplied with an assisting force for rotating the valve body 8 to move the valve body 8 in the opening direction via a drive rod 16. I have.

In the flow control valve 1 having the above structure, the inlet 4a of the valve body 2 is connected to the engine (water jacket) side, the outlet 4b is connected to the radiator side, and the stepping motor 3 The pair of two-phase wound coils 12a and 12b are connected to the control device 31 as shown in FIG. When an output signal corresponding to the state of the engine is supplied to the stepping motor 3 by the control device 31, the drive rod 16 is axially advanced / retracted by the forward / reverse rotation of the rotor 14, and accordingly, The valve element 8 changes the opening of the outlet 4b. This makes it possible to control the amount of circulation of the cooling water from the radiator side to the engine side.

Here, when the flow control valve 1 is used,
A pair of two-phase wound coils 12a, 1 of the stepping motor 3
2b, that is, the above-described first to fourth coils 21 to 24
A description will be given of a case where the second coil 22 between the common terminal C1 and the third terminal # 3 is disconnected (see FIG. 3). That is, FIG. 5A shows that the above-described first to fourth stators A to D and the rotor 14 are developed in the rotation direction, and the polarity of each of the stators A to D and the rotor 14 when the rotor 14 rotates in one direction. The arrows in the figure show the suction force and the repulsion force acting on the rotor 14. FIG. 5B shows the first to fourth coils 21 to 2.
FIG. 4 is a diagram illustrating an excitation order of No. 4 and illustrates a state where the second coil 22 is disconnected. Both figures show the passage of time from top to bottom.

In such a state, since the second coil 22 between the common terminal C1 and the third terminal # 3 is disconnected, a magnetic force is generated in the first and second stators A and B. Although intermittent, the third and fourth stators C and D
Generates magnetic force normally. Therefore, some drive torque is generated in the rotor 14. On the other hand, at this time, an auxiliary force for rotating the valve element 8 in the opening direction is supplied to the rotor 14 by the coil spring 17. For this reason, the rotor 14 can rotate in the direction of moving the valve body 8 in the opening direction, and in the control device 31, any one of the first to fourth coils 21 to 24 (see FIG. 3) is used. Even if the wire breaks, the valve 8
Can be moved in the opening direction.

Therefore, in the flow control valve 1 according to the present embodiment, when the valve element 8 is at the fully closed position shown in FIG. 1, the first to fourth coils 21 to 24 (see FIG. 3) are turned off. Even if one of them is disconnected, the circulation amount of the engine cooling water can be increased by controlling the drive of the valve body 8 to the open position. That is, the fail-safe operation can be realized at a lower cost with a simple structure and without much increase in the number of parts as compared with those described in the related art.

In addition, in the flow control valve 1, even when the stepping motor 3 fails as described above, the drive of the valve body 8 can be controlled to the open position. Even if it occurs in, the circulation amount of cooling water can be increased,
It is possible to prevent the engine from overheating. Therefore, the usability is better than that described in the related art.

In this embodiment, the flow control valve is provided with the coil spring 17 as the auxiliary force supply means of the present invention, and the spring force is used as the auxiliary force when rotating the rotor 14 in a predetermined direction. However, other than this, a configuration may be adopted in which another force such as a fluid pressure is used as the auxiliary force without providing the auxiliary force supply unit. For example, in a flow control valve in which a certain pressure or more such as water pressure or oil pressure is constantly applied to the valve body during use, the internal flow path configuration is controlled by the valve opening force and valve closing force generated in the valve body due to water pressure or the like. What is necessary is just to make it the structure which becomes powerful. In that case, other components such as the coil spring 17 in the present embodiment become unnecessary, and the number of components can be further reduced.

In the present embodiment, the flow control valve mainly used in the cooling water flow control device for the internal combustion engine has been described. However, the present invention is not limited to this, and is caused by alternately energizing a plurality of coils. In a stepping motor type driving device that drives an object by the rotational force of the rotor of the stepping motor, similar to the present embodiment,
If the configuration is such that an auxiliary force that constantly supplies an auxiliary force when the rotor rotates in a predetermined direction can be obtained, even if disconnection occurs in any of the plurality of coils, the determined rotor can be used. The object can be driven in one direction corresponding to the rotation direction of. Therefore, by setting the position in one direction corresponding to the determined rotation direction of the rotor as the drive position of the object during the fail-safe operation, the structure is simple, and the number of parts is not increased so much. It is possible to realize the fail-safe operation at a lower cost.

Further, in this embodiment, a four-phase winding two-phase excitation unipolar drive type is shown as the stepping motor. In addition, when any one of the plurality of coils is disconnected, The present invention can be implemented by using other types of stepping motors as long as a small drive torque is generated in the rotor by exciting the remaining normal coils.

[0030]

As described above, in the stepping motor type driving apparatus according to the first aspect, even if any one of the plurality of coils in the stepping motor is disconnected, the determined rotation direction of the rotor is determined. The object can be driven in one direction corresponding to. Therefore, by setting the position in one direction corresponding to the determined rotation direction of the rotor as the drive position of the object during the fail-safe operation, the structure is simple and the number of parts is not increased so much. Thus, a fail-safe operation can be realized at lower cost.

Further, in the flow control valve according to the second and third aspects, even when a disconnection occurs in any one of the plurality of coils in the stepping motor, it corresponds to the determined rotation direction of the rotor. The valve body can be driven to either the open position or the closed position. For this reason, by setting the open position or the closed position corresponding to the determined rotation direction of the rotor as the drive position of the valve element at the time of the fail-safe operation, the structure is simple and the number of components is not increased so much. Thus, a fail-safe operation can be realized at lower cost.

[0032]

[Brief description of the drawings]

FIG. 1 is a sectional view of a flow control valve showing one embodiment of the present invention.

FIG. 2 is a sectional view of a main part showing a state in which a valve body is at a fully open position.

FIG. 3 is a schematic sectional view showing a specific structure of a stepping motor.

FIG. 4 is a schematic explanatory view showing a magnetic force applied to a rotor.

FIG. 5A is a schematic diagram illustrating a magnetic force applied to a rotor of a stepping motor, and FIG. 5B is a diagram illustrating an excitation order of a plurality of coils.

FIG. 6 is a sectional view showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow control valve 3 Stepping motor 8 Valve body 12a, 12b Coil (a plurality of coils) 13a, 13b Stator 14 Rotor 17 Coil spring (auxiliary force supply means)

Claims (3)

[Claims] 1. A stepping motor type driving device for driving an object by a rotating force of a rotor of a stepping motor generated by alternately energizing a plurality of coils, wherein the rotor rotates in a predetermined direction. A stepping motor type driving device comprising an auxiliary force supply means for constantly supplying the auxiliary force. 2. A flow control valve for controlling the flow rate of a fluid by driving a valve body to open and close by a rotational force of a rotor of a stepping motor generated by alternately energizing a plurality of coils, wherein the rotor is a fixed one. A flow control valve comprising: an auxiliary force supply unit that constantly supplies an auxiliary force when rotating in a direction to the rotor via the valve body. 3. A flow control valve for controlling the flow rate of a fluid by driving a valve body to open and close by a rotating force of a rotor of a stepping motor generated by a plurality of coils being alternately energized, wherein the rotor has a predetermined one. A flow control valve, comprising: a flow path structure that constantly generates an assisting force in rotating the valve body by the pressure of the fluid in the valve body.