JPH07335437A - Energization control method in electromagnetic drive device - Google Patents

Abstract

(57) [Abstract] [Purpose] An armature, a pair of electromagnets which are arranged to face each other on both sides of the armature so that an electromagnetic attraction force can be applied to the armature, and the armature is biased to both electromagnet sides respectively. In an electromagnetic drive device including a pair of return springs, it is ensured that an armature is attracted to and held by an electromagnet regardless of operating conditions. [Structure] The energization amount of an electromagnet is changed according to operating conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an armature, a pair of electromagnets which are arranged opposite to each other on both sides of the armature so that an electromagnetic attraction force can be applied to the armature, and the armature is attached to both electromagnet sides. The present invention relates to an energization control method in an electromagnetic drive device including a pair of biasing return springs.

[0002]

2. Description of the Related Art Conventionally, such an electromagnetic drive device is known from, for example, US Pat. No. 5,222,714.

[0003]

Conventionally, in such an electromagnetic drive device, the electromagnet is generally energized and controlled at a constant energizing amount. However, the electromagnetic attraction exerted by the electromagnet decreases as the temperature rises with the same amount of electricity, so it becomes easier for the electromagnet to fail to attract and hold the armature as the temperature rises, and the inertial force of the armature causes its operation. If the electromagnetic force is increased as the frequency is increased, it becomes easy to fail to hold the armature by the electromagnet with the same electromagnetic force.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an energization control method in an electromagnetic drive device in which an electromagnet reliably attracts and holds an armature regardless of operating conditions. .

[0005]

In order to achieve the above object, the invention according to claim 1 is arranged so as to face the armature and both side surfaces of the armature so that an electromagnetic attraction force can be applied to the armature. A pair of electromagnets,
In an electromagnetic drive device including a pair of return springs for urging the armature toward both electromagnets, the energization amount of the electromagnet is changed according to an operating condition.

According to the second aspect of the invention, in addition to the structure of the first aspect of the invention, the energization amount is increased according to the temperature rise of the electromagnet.

According to the third aspect of the invention, in addition to the configuration of the first aspect of the invention, the energization amount is increased as the number of times the armature operates per unit time increases.

Further, the invention according to claim 4 is characterized in that an armature, a pair of electromagnets arranged to face both sides of the armature so that an electromagnetic attraction force can be applied to the armature, and the armatures on both electromagnet sides. An electromagnetic drive device including a pair of biasing return springs is characterized in that the energization amount of the electromagnet is changed in accordance with the distance between the armature and the electromagnet.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a valve operating system for an internal combustion engine will be described below with reference to the drawings.

1 to 4 show one embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an electromagnetic drive device, FIG. 2 is a circuit diagram showing the structure of a detector, and FIG. FIG. 4 is a timing chart of the detector output according to the energized state, and FIG. 4 is a diagram showing a set map of the energized current.

First, in FIG. 1, the cylinder head 1 is provided with an intake valve port 3 that opens toward the combustion chamber 2, and an intake valve as an engine valve V that opens and closes the intake valve port 3 is an electromagnetic drive device 4. It is driven to open and close.

The electromagnetic drive device 4 includes a housing 5 made of a non-magnetic material, which is provided on the cylinder head 1, and an armature 7 which is provided integrally with the stem 6 of the engine valve V and is movably accommodated in the housing 5. , A valve closing electromagnet 8 fixedly disposed in the housing 5 at a position facing the upper surface of the armature 7 so as to be able to exert an electromagnetic force for attracting the armature 7 to close the engine valve V, and the armature 7 A valve-opening electromagnet 9 fixedly arranged in the housing 5 at a position facing the lower surface of the armature 7 so as to be able to exert an electromagnetic force for attracting and opening the engine valve V, and toward the valve-closing direction of the engine valve V. A valve closing side return spring 10 for urging the armature 7 and a valve opening side return spring 11 for urging the armature 7 in the valve opening direction of the engine valve V are provided.

The housing 5 is formed in a cylindrical shape with both ends closed, and a guide cylinder 12 fixedly mounted on the cylinder head 1 by slidably fitting the stem 6 of the engine valve V.
Is projected into the housing 5 from the lower end of the housing 5. Thus, in the housing 5, a disc-shaped armature 7 is integrally fixed to an intermediate portion of the stem 6 protruding from the guide cylinder 12.

The valve-closing electromagnet 8 is fixedly disposed in the upper portion of the housing 5 so as to face the upper surface of the armature 7, and has a substantially U-shaped cross section open to the armature 7 side. The coil 14 is housed in a fixed core 13 that has a shape and is formed in a ring shape that surrounds the stem 6 coaxially. The valve-opening electromagnet 9 is fixedly arranged in the lower portion of the housing 5 so as to face the lower surface of the armature 7.
A coil 16 is housed in a fixed core 15 having a substantially U-shaped cross-section open to the side and formed in a ring shape that coaxially surrounds the stem 6.

The valve-closing side return spring 10 is housed in the housing 5 so as to exert an upward spring force on the armature 7, and the valve-opening side return spring 11 is directed downward to the armature 7. It is housed in the housing 5 so as to exert a spring force. Both return springs 10, 1
1 is for holding the armature 7 at the equilibrium neutral position in the central portion between the electromagnets 8 and 9 when the electromagnets 8 and 9 are in the demagnetized state, and in that state, the engine valve V is closed. It is at an intermediate position between the position and the valve opening position.

In order to detect that the engine valve V is in the closed position when the valve-closing electromagnet 8 is excited to close the engine valve V, the engine is provided in the upper part of the housing 5 with an engine. The damper 1 that abuts on the upper end of the stem 6 as an interlocking member that operates integrally with the armature 7 when the valve V reaches the closed position.
7 and a piezoelectric element 18 that receives pressure from the stem 6 via the damper 17 are fixedly arranged. On the other hand, in order to detect that the engine valve V is in the open position when the valve opening electromagnet 9 is excited to open the engine valve V, the valve opening electromagnet 9 is moved to the armature 7. On the opposite surface, the engine valve V
The piezoelectric element 18, which receives pressure from the armature 7 when the valve reaches the valve opening position, is fixedly arranged.

The piezoelectric element 18 has a characteristic of generating a voltage according to the pressure received from the armature 7 and the stem 6, and is connected to a detector 20 as shown in FIG.

The detector 20 is connected in series between the lines L ₁ and L ₂ connected to both ends of the piezoelectric element 18, and a resistor 21 and a capacitor 22 connected in series between the lines L ₁ and L _2. A diode 23 and a resistor 24, and a diode 25 connected in series between the lines L ₁ and L ₂
And resistors 26 and 27, and a Zener diode 28 connected between the connection point of the resistors 26 and 27 and the line L _1.
And a differential amplifier 29 having a non-inverting input terminal connected to the connection point of the resistors 26 and 27 and an output terminal connected to the inverting input terminal, and the output terminal of the differential amplifier 29 and the line L ₁ In between, an output V _OUT corresponding to the output voltage V _P of the piezoelectric element 18 is obtained.

Here, the coils 14, 16 of the electromagnets 8, 9
The output timings of the piezoelectric element 18 and the detector 20 accompanying the excitation of are as shown in FIG. That is, when full energization of the coil 14 or 16 is started at time t ₁ , an energizing current flows through the coil 14 or 16 as shown in FIG. 3B, and the energizing current becomes a certain value or more at time t _2. The movement of the armature 7 is started at, and the movement of the armature 7 is completed at time t ₃ when the energizing current is reduced according to the start of movement of the armature 7, that is, when the engine valve V reaches the fully closed position or the fully opened position. As shown in FIG. 3C, the piezoelectric element 18 outputs the output voltage V _P in response to the pressure from the armature 7. That is, the fully closed position or the fully open position of the engine valve V is detected by the detector 20. In response to the detection by the detector 20, at a time t ₄ slightly after the detection time t ₃ , as shown in FIG.
Chopping control is started, which results in FIG. 3 (b).
The energizing current is limited as shown by. Further, when the energization of the coil 14 or 16 is finished at time t ₅ , the armature 7 starts to move in the valve opening direction or the valve closing direction at time t ₆ when the output of the piezoelectric element 18 decreases.

By the way, the detector 20 includes the coil 1
In the electronic control unit ECU for controlling the energization of 4, 16
Included in the electronic control unit ECU
Is the temperature T of the valve closing electromagnet 8.₁Temperature detector S for detecting
_T1, The temperature T of the valve opening electromagnet 9₂Temperature detector S for detecting
_T2, And engine speed N_ERotation speed detector to detect
S _NEAre connected.

In the electronic control unit ECU, the temperature is
Degree T₁, T₂And engine speed N_EAccording to
The energizing current is set as follows. Ie temperature
T₁, T ₂And engine speed N_EStep by step with increasing
The energizing current is set to increase. Thus, FIG.
The curve A shown by is below the electromagnetic valve for closing and opening.
Failure to grab armature 7 by stones 8 and 9 may occur
There is a certain energizing current, and the set energizing current is the curve A
It is set so that it will be a larger value.

The operation of this embodiment will now be described. The electromagnetic attraction forces exerted by the valve-closing and valve-opening electromagnets 8 and 9 decrease as the temperature rises if the amount of electricity is the same. As the temperatures T ₁ and T ₂ of the electromagnets 8 and 9 rise, the energizing currents of the electromagnets 8 and 9 are increased stepwise, so that the attraction electromagnetic force is prevented from decreasing despite the temperature rise, and the electromagnets 8 and 9 are prevented from decreasing. It is possible to prevent the failure of gripping the armature 7 due to 8 and 9 as much as possible, and to achieve a reliable opening / closing operation of the engine valve V.

When the number of operations of the armature 7 per unit time increases as the engine speed N _E increases, the inertial force increases and the electromagnets 8 and 9 tend to fail to grip the armature 7. However, as the engine speed N _E, that is, the number of actuations of the armature 7 per unit time increases, the energizing currents of both electromagnets 8 and 9 are increased stepwise, so that the inertial force of the armature 7 increases its operating frequency. Even if it increases in accordance with the above, it is possible to prevent occurrence of a failure to grip the armature 7 by increasing the attraction electromagnetic force by the electromagnets 8 and 9, and to obtain a reliable opening / closing operation of the engine valve V.

Thus, the temperatures T ₁ and T of both electromagnets 8 and 9 are
₂ and the engine speed N _E, that is, the energization current is changed in accordance with the number of times the armature 7 is operated per unit time, so that the armature 7 can be reliably operated and the electric power consumed by the electromagnets 8 and 9 is wasted. It is also possible to avoid consumption, which can also contribute to reduction of power consumption.

By the way, the detector 20 includes both electromagnets 8 and 9.
It is possible to detect that the armature 7 is not properly grasped by the user. If the armature 7 is not properly grasped due to some reason, the energizing current may be controlled to increase as indicated by an arrow in FIG. It is possible, and when it fails to grab, the armature 7 can be reliably attracted and held by either of the electromagnets 8 and 9.

As another embodiment of the present invention, as shown in FIG. 5, according to the temperatures T ₁ and T ₂ and the engine speed N _E, that is, the number of operations of the armature 7 per unit time,
It is also possible to set the energizing current to increase smoothly.

As yet another embodiment of the present invention, the energization amount of the electromagnets 8 and 9 is set to the armature 7 and the electromagnets 8 and 9.
It may be controlled so as to decrease as the distance between the switch 9 and 9 decreases. At this time, as shown in FIG. 3 (b), it is possible to detect the change in the energizing current according to the movement of the armature 7 and to estimate the distance between the armature 7 and the electromagnets 8 and 9. Alternatively, the interval may be estimated based on the time from the start of movement of the armature 7.

Thus, the amount of electricity applied to both electromagnets 8 and 9 is reduced as the distance between the armature 7 and both electromagnets 8 and 9 is reduced, so that both electromagnets 8 and 9 are wasted. It is possible to prevent power consumption, and to reliably prevent the armature 7 from failing to be gripped.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. It is possible to do.

For example, the present invention is not limited to the valve operating device,
It can be widely applied to an electromagnetic drive device formed by connecting an operating member to an armature.

[0031]

As described above, according to the first aspect of the present invention, the energization amount of the electromagnet is changed according to the operating condition, so that the attraction electromagnetic force of the electromagnet is changed according to the operating condition to secure the armature. It is possible to perform various suction and hold operations and prevent wasteful power consumption.

According to the second aspect of the invention, in addition to the structure of the first aspect of the invention, the energization amount is increased according to the temperature rise of the electromagnet, so that the electromagnet is attracted despite the temperature rise. It is possible to prevent a decrease in electromagnetic force.

According to the invention of claim 3, in addition to the configuration of the invention of claim 1, the energization amount is increased as the number of times of operation of the armature per unit time is increased. Despite the increase in inertial force, the electromagnetic attraction of the electromagnet is increased, so that the armature can be reliably attracted and held.

Further, according to the invention of claim 4, the energization amount of the electromagnet is changed in accordance with the interval between the armature and the electromagnet, so that wasteful power consumption in the electromagnet is avoided and the armature can be reliably operated. It is possible to hold by suction.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electromagnetic drive device.

FIG. 2 is a circuit diagram showing a configuration of a detector.

FIG. 3 is a timing chart of the detector output according to the energization state of the coil.

FIG. 4 is a diagram showing a setting map of energization current.

FIG. 5 is a diagram showing a setting map of energization current in another embodiment.

[Explanation of symbols]

 4 ... Electromagnetic drive device 7 ... Armature 8, 9 ... Electromagnet 10, 11 ... Return spring

Claims (4)

[Claims] 1. An armature (7), a pair of electromagnets (8, 9) facing each other on both sides of the armature (7) for enabling an electromagnetic attraction force to act on the armature (7), A pair of return springs (1) for urging the armature (7) toward the electromagnets (8, 9) respectively.
0, 11), the energization control method in the electromagnetic drive device is characterized in that the energization amount of the electromagnets (8, 9) is changed according to the operating condition. 2. The energization control method for an electromagnetic drive device according to claim 1, wherein the energization amount is increased according to the temperature rise of the electromagnets (8, 9). 3. The energization control method for an electromagnetic drive device according to claim 1, wherein the energization amount is increased as the number of times the armature (7) operates per unit time increases. 4. An armature (7), a pair of electromagnets (8, 9) arranged opposite to each other on both sides of the armature (7) so that an electromagnetic attraction force can be applied to the armature (7), A pair of return springs (1) for urging the armature (7) toward the electromagnets (8, 9) respectively.
0, 11), the electromagnetic drive characterized in that the amount of electricity supplied to the electromagnets (8, 9) is changed in accordance with the distance between the armature (7) and the electromagnets (8, 9). Energization control method in device.