JPS6053290A - Electro-magnetic pressure control valve - Google Patents

Abstract

PURPOSE:To minimize the influence of variation in temperature and restrain the hysterisis to a minimum by applying a load, which corresponds to the pressure in a pressure port, to the end of a spool which makes contact with an armature at the other end thereof. CONSTITUTION:When the voltage of an AC power supply 46 is increased, the force which is applied rightward to a spool 28 by an armature 40 is increased so that the spool 28 is forced to move rightward against the resilient force of a spring 64. As a result, the fluid passage area of a notch 32 is reduced to cause the throttle effect to be enhanced, on account of which the oil pressure in a pressure port 12 is increased. The increased pressure is transmitted to a plunger 54 through a feedback passage 52. The pressure in the pressure port 12 may be, therefore, varied arbitrarily by varying the attraction force of the armature 40.

Description

TECHNICAL FIELD The present invention relates to an electromagnetic pressure control valve, and more particularly to an electromagnetic pressure control valve using a solenoid coil excited by alternating current.

Prior Art Conventional electromagnetic pressure control valves use a solenoid coil that is excited by direct current (L), but the force that attracts the armature of this direct current solenoid coil is easily affected by temperature changes. However, there was a drawback that the pressure control characteristics inevitably changed significantly. The attraction force of a DC solenoid assembly is determined by the current flowing through the solenoid coil, but since the resistance of the solenoid coil varies considerably depending on the temperature, the attraction force of the solenoid coil is greatly affected by temperature. To avoid this, it was necessary to use a constant current power supply.

In addition, in a pressure control valve using a DC solenoid assembly, hysteresis tends to be large when increasing and decreasing the pressure, and in order to reduce this, alternating current is superimposed on the direct current used to excite the solenoid coil. Countermeasures such as -1 have been taken, but they are still not sufficient due to the influence of residual magnetism, and the reality is that an electromagnetic pressure control valve with even lower hysteresis has been awaited.

Purpose of the Invention In view of the above circumstances, the present invention has been made with the object of providing an electromagnetic pressure control valve that is less susceptible to temperature changes and has less hysteresis.

Structure of the Invention In order to achieve this object, the electromagnetic pressure control valve according to the first invention comprises +a) an AC power supply device with variable voltage or current; C1: an armature movably disposed inside the solenoid coil; and a drain boat, and a housing that accommodates the spool in a state where the spool is movable in the axial direction and the land cuts off communication between the pressure boat and the drain boat;
l A pressure boat and a drain boat are communicated with each other while giving a squeezing effect to the land of the spool, and when the spool moves toward the second end opposite to the first end, the squeezing effect becomes thicker. and a feedback mechanism for feeding back a force corresponding to the pressure of the sweat cover to the second end of the spool.

Moreover, the electromagnetic pressure control valve according to the second invention is configured to include a vibration absorbing member in addition to the above-mentioned components. This vibration absorbing member has an elastic deformation smaller than the axial dimension of the notch, and when the spool and the armature are brought into direct contact, there is a gap between the two, or between the two with another rigid member interposed between them. When the rigid member is brought into contact with the armature or the spool, it is interposed between the rigid member and the armature or spool.

Functions and Effects of the Invention If alternating current is used to excite the solenoid coil as described above, the proportion of resistance in the impedance of the solenoid coil becomes significantly small, so that the armature suction of the solenoid coil based on two-grade changes is reduced. Changes in force are also significantly reduced, resulting in an electromagnetic pressure control valve that is less susceptible to temperature changes.

In addition, DC solenoid assemblies are affected by residual magnetism and have large hysteresis, but when AC solenoid assemblies are used, residual magnetism is small, and since vibrations occur in the armature and spool, hysteresis due to frictional resistance is also reduced. A very small electromagnetic pressure control valve is obtained. However, AC solenoid assemblies have not been considered in the past because they are accompanied by large vibrations in the armature, and the state of vibration changes markedly depending on the position of the armature, especially when the stroke range is widened.

In this respect, in the first invention, the armature is brought into direct contact with the spool, and when brought into contact indirectly, the armature is brought into contact through a rigid member instead of through an elastic member such as a spring as in the conventional method. As a result, only a small stroke of the armature is required. Further, when the armature and the valve element (spool) are brought into rigid contact as described above, the vibration of the armature is transmitted to the valve element, causing the -jC element to vibrate. Therefore, if a 7-seating valve is used, if the valve element vibrates, the area of the orifice formed by the seat and the valve element will change greatly due to the vibration, and the controlled pressure will also fluctuate greatly, making it stable. Unable to obtain pressure control. However, in the first invention, a spool is used as a valve, and run 1
- Since we decided to use the notch formed in the
This makes it possible to obtain stable pressure control characteristics.

Furthermore, if a vibration absorbing part is interposed between the armature and the spool as in the second invention, the vibration of the spool can be reduced to r9! The friction can be reduced to an appropriate size that does not adversely affect pressure control. Moreover, if the elastic deformability of the vibration absorbing member is made small, equal to or smaller than the axial dimension of the notch, the stroke of the armature will increase somewhat due to the elastic deformation of the vibration absorbing member. It is unlikely that the situation will change significantly.

Embodiments Hereinafter, two or three embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a housing which is the main body of the hydraulic control valve.For convenience of manufacture, it is divided into three parts, but after assembly, it functions as an integrated housing. This housing 10 is provided with a pressure boat 12 and a drain boat 14 , the pressure boat 12 being connected to a pump circuit 20 by a line 18 with a restriction 16 , while the drain boat 114 is connected to a tank by a line 22 . 24. Therefore, a portion of the hydraulic oil pumped from the tank 24 by the pump 26 is guided to the pressure boat 12 by the line 18, and from the drain boat 14 to the line 22.
It will be returned to the tank 24 through the process.

The flow path from this pressure boat 12 to the drain boat 14 is constricted by a spool 28. The spool 28 is fitted into a spool hole formed in the housing 10 substantially oil-tightly and slidably in the axial direction, and is provided with a land 30 at one end. Connection between Land No. 30 pressure boat 12 and drain boat 14 [1
However, this land 30 is formed with a notch 32 as shown in the enlarged view in FIGS. The annular groove 34 is ejected into the low pressure chamber 36 through the pressure notch 32.
As is clear from FIG. 2, the end portion of the land 30 is formed to be deep.

Therefore, as the spool 28 moves to the right in FIG. 1, the flow path area in the notch 32 decreases, and the throttling effect on the hydraulic oil flowing from the pressure boat 12 to the drain boat 14 increases.

An armature tube 38 is fixed to the end of the housing 10 on the low pressure chamber 36 side by screwing, and an armature 40 is disposed within the armature tube 38 so as to be movable in the axial direction. A working protrusion 42 protruding from one end surface of the spool 40 is adapted to come into contact with one end of the spool 28. Further, a solenoid coil 44 is fixed to the outside of the armature tube 38, and this solenoid coil 44 is connected to an AC power source 46 whose voltage (or current) is variable.
It is connected to the. Therefore, the solenoid coil 44
When alternating current is applied to the solenoid coil 44, the armature 40 will be attracted to the central position of the solenoid coil 44 and will apply a force to the spool 28 in the positive direction, ie, to the right in FIG. 1, through the actuation projection 42. This rightward force increases or decreases as the voltage applied to the solenoid coil 44 by the AC power supply 46 increases or decreases.

A feedback mechanism 50 also applies a force in the opposite direction, that is, to the left, to the spool 28, and the spool 28 is stopped at a position where this force and the rightward force by the armature 40 are balanced. The feed bank mechanism 50 includes a backup plunger 54 which operates under pressure from the pressure boat 12 guided by a feed port passage 52 formed in the housing 10. The tip end of the backup plunger 54 is fixed to a piston 58 that is fitted in an oil-tight and slidable manner within an oil chamber 56 formed in the housing 10. The piston 58 is provided facing the end of the spool 28 opposite to the side that contacts the armature 40, and is supported by a spring 60 with a large elastic force disposed between the spool 28 and the housing 10. is biased in the direction away from the Further, a spring 64 with a small elastic force is provided between the piston 58 and another piston 62 fixed to the end of the spool 28, and the elastic force of this spring 64 is applied to the spool 28 through the piston 62.
can be added to.

By disposing the pistons 58 and 62 in the oil chamber 56 as described in 1., the oil chamber 56 becomes the -th chamber 66. It is divided into a second chamber 68 and a third chamber 70, of which the first chamber 66 communicates with the tank 24 through a drain boat 722, and the third chamber 70 communicates with the low pressure chamber 36 through a communication passage 74. I'm forced to.

Further, the second chamber 68 is communicated with the third chamber 70 by a communication passage 76 that is formed between the outer peripheral surface of the piston 62 and the inner peripheral surface of the oil chamber 56 and has a throttle effect.

When a constant voltage is applied by the AC power supply 46 to the solenoid coil 44 of the hydraulic control valve configured as described above, and a constant hydraulic pressure is introduced from the pump circuit 20 to the pressure port 12, the spool 28 It is stopped at the position shown in Figure 1.

That is, the rightward force that the armature 40 applies to the spool 28 based on the attraction force of the solenoid coil 44;
The leftward force exerted by spring 64 on spool 28 is balanced.

When the voltage of the AC power supply 46 is increased from this state, the rightward force applied by the armature 40 to the spool 28 increases, causing the spool 28 to move to the right against the elastic force of the spring 64. As a result, the flow path area in the notch 32 decreases and the throttling effect 3 increases, so that the oil pressure in the pressure boat 12 increases, and this is transmitted to the plunger 54 through the feedback passage 52. As a result, the plunger 54 moves the piston 58 forward against the elastic force of the spring 60, thereby compressing the spring 64 and increasing the leftward force on the spool 28. That is, as the pressure in the pressure boat 12 increases, the piston 58 advances, and this advancement increases the elastic force of the spring 64. As a result, the amount of pressure increase in the pressure boat 12 and the spool 28 increase. The amount of increase in the applied leftward force is proportional to the amount of increase.

Then, the spool 28 stops when this leftward force and the above-mentioned rightward force by the armature 40 are balanced, so the pressure of the pressure boat 12 changes the suction force of the armature 40, that is, the voltage of the AC power source 46. can be changed arbitrarily by The hydraulic pressure of this pressure boat 12 can be taken out and used for various purposes.

Note that if the voltage of the AC power supply 46 is suddenly increased and the rightward force applied to the spool 28 by the armature 40 is suddenly increased, the piston 58
Before the spring moves forward and increases the elastic force of the spring 64, the spool 28 moves to the right, and the throttling effect in the notch 32 becomes too strong, causing a so-called overload in which the pressure in the pressure boat 12 temporarily becomes excessive. Although a shoot is likely to occur, this hydraulic control valve prevents this overshoot from occurring. That is, the piston 58, which advances as the oil pressure of the pressure boat 12 increases, pushes out the hydraulic oil in the second chamber 68 to the drain boat 14 through the third chamber 70 and the communication passage 74, and furthermore, Second room 6
8 and the third chamber 70 are communicated only by a narrow communication path 76, so when the oil pressure of the pressure boat 12 suddenly increases and the piston 58 moves forward rapidly, the air from the second chamber 68 A throttling effect is applied to the flow of hydraulic oil into the third chamber 70, and the oil pressure in the second chamber 68 increases, which applies a leftward force to the spool 2 via the piston 62, and this force The larger the forward speed of the piston 558, the larger the pressure boat 12.
The more rapidly the oil pressure rises, the greater it becomes, counteracting the rightward force of the armature 40 and preventing the spool 28 from rapidly moving to the right.

As is clear from the above description, in this hydraulic control valve, hydraulic control is performed by moving the armature 40 by the same amount as the spool 28, and moreover, the spool 28
Since the movement of 8 is small, the armature for hydraulic control, 1. The stroke of the a 40 can be small. for example,
The length of the notch 32 formed in the spool 28 of this embodiment is one length, and the length of the notch 32 formed in the spool 28 of this embodiment is shorter than the length of the cutout 32 of the armature 40.
This allows a wide range of hydraulic control to be performed. Therefore, it is less affected by changes in the attraction force due to changes in the position of the armature 40 with respect to the solenoid coil 44, and the electric circuit in the cylinder can provide sufficient control characteristics for practical use. For example, it is sufficient to control the voltage and current of a commercial power supply for 50 or 60 cycles using resistors or 6 risks.

Moreover, this hydraulic control valve is extremely unlikely to be affected by temperature changes in the solenoid coil. This is clear from FIGS. 4 and 5. FIG. 4 is a graph showing the change in suction force when the solenoid coil 44 used in this example is in a cooling state of 30°C and when it is in a saturated temperature state of 150°C.
The figure is a graph showing the change in attraction force between the cooling state and the saturated temperature state when an equivalent solenoid coil is excited with direct current.Comparing the two, it is clear that this hydraulic control valve uses a conventional direct current solenoid coil. You can see how it is less susceptible to temperature effects compared to hydraulic control valves.

Moreover, in this hydraulic control valve, the hysteresis between increasing and decreasing the hydraulic pressure is so small that it cannot be measured with a normal meter.

Although the functions and effects of Structure 2 have been described in detail regarding one embodiment of the present invention, the present invention is not limited to this seventh embodiment, and can be implemented in various forms.

An example is shown in FIG. In this example, the first
In addition to the pressure boat 12 shown in the embodiment shown, another pressure port door 7 is provided.
The hydraulic pressure of the pump circuit 20 is guided to the pump circuit 20 by a pipe line 18. And G Holland 3 on spool 28
0 and notch 32 plus land 78 and notch 7
9 is provided. The hydraulic oil led to the pressure port door 7 flows through the notch 79 to the pressure boat 12, and further from the pressure boat 12 through the notch 32 to the low pressure chamber 36. The hydraulic pressure of 820 is reduced by the throttling effect of the notch 79 and the pressure boat 1
2, and the hydraulic pressure of this pressure boat 12 is further controlled by the throttling effect of the notch 32. When the spool 28 is moved in the forward direction,
The flow path area of the notch 79 is increased and the notch 32
By decreasing the flow area of the pressure boat 12 or blocking the flow 8, the hydraulic pressure of the pressure boat 12 is increased, and when the boat is moved in the opposite direction, the flow area of the notch 32 is increased and the flow is The hydraulic pressure in the pressure port 12 is reduced by reducing the path area or cutting off the flow. The hydraulic pressure of the pressure boat 12 controlled in this manner is taken out to the outside and used for various purposes. Other parts are the same as those in the embodiment shown in Fig. 1, so corresponding parts are given the same reference numerals and detailed explanations are omitted. There is an advantage that only a small amount of hydraulic oil is required to be returned from the boat 14 to the tank 24.

Another embodiment of the invention is shown in FIGS. 7 and 8. 7th
The one shown in the figure corresponds to the embodiment shown in FIG. 1 in which the backup plunger 54 is brought into direct contact with the spool 28, and a variable throttle valve 80 is provided in the middle of the feedback passage 52 to prevent vibration of the spool 28. It is being In addition, in the pressure control valve shown in FIG. 8, a vist 782 is fixed to the rear end of the plunger 54,
A first chamber 83 and a second chamber 84 on both sides of the valve 2 are communicated with each other by a communication passage 86, and a variable throttle valve 88 is provided in the middle of the communication passage 86.

Cholera hiss I-782, series 1trl li'386 A
The variable throttle valve 88 is also provided to prevent vibration of the spool 28. Since the other parts are the same as those in the embodiment shown in FIG. 1, corresponding parts will be denoted by the same symbols and detailed explanations will be omitted.

In the above two embodiments, the hack-up plunger 54
The operating force of the back-up plunger 54 is transmitted as it is to the spool 28, and the diameter of the backup plunger 54 cannot be made as small as possible due to restrictions on kneeling. It is necessary to make the solenoid coil 44 and the armature 40 into dolls so that they can resist the actuation force of the solenoid coil 44! Although there are certain disadvantages, the f1' hack mechanism can be simplified.
! Therefore, it is suitable as a hydraulic control valve used in a relatively low pressure range.

Yet another embodiment of the invention is shown in FIG. In this embodiment, a vibration absorbing member 90 is added to the embodiment shown in FIG. That is, a cup-shaped holding member 92 is fitted to the tip of the working projection 42 of the armature 40, and a vibration absorbing member 90 is disposed between the bottom of this holding member 92 and the tip surface of the working projection 42. . Therefore, the armature 40 and the spool 28 come into contact with each other via the vibration absorbing member 90. The vibration absorbing member 90 is made of rubber and can be elastically deformed, but its elastic deformability, that is, the amount by which it can be elastically deformed without being damaged or plastically deformed, is smaller than the dimension of the notch 32 in the spool axial direction. ing.

The vibration absorbing member 90 absorbs vibrations of the armature 40,
In order to reduce the amount of vibration transmitted to the spool 28, an amount of vibration suitable for reducing the frictional force with the housing 10 is transmitted to the spool 28, and the vibration of the spool 28 is transmitted to the spool 28 in an amount suitable for reducing the friction force with the housing 10. vibration is prevented. Although the vibration absorbing portion 4A90 is made of rubber in the first embodiment, it is also possible to use a metal elastic member.

In addition, although all of the embodiments described above were hydraulic control valves,
It is possible to apply the present invention to pressure control valves that control the pressure of gases such as air as well as liquids other than music, and other examples may be used without departing from the spirit of the present invention. various modifications based on the knowledge of those skilled in the art,
It goes without saying that the invention can be practiced in modified forms.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a hydraulic control valve according to an embodiment of the present invention. FIG. 2 is an enlarged front view (partially cut away) of the spool used in the hydraulic control valve 1, and FIG. 3 is a plan view showing the main parts of the spool. FIGS. 4 and 5 are graphs showing changes in attractive force based on temperature changes of the solenoid coil when the same solenoid coil is excited with alternating current and when excited with direct current. 6 to 9 are front sectional views showing other embodiments of the present invention, respectively. 2 10: Housing 12: Pressure port 14: Drain port 16: Restriction 20: Pump circuit 28 Varnish spool 30.78: Land 32, 79: Notch 38: Armature tube 40: Armature 44: Solenoid coil 46: AC power supply 50: Feed Bank mechanism 52: Feed bank mechanism 54: Bank up plunger 58, 627 piston 6o, 64 spring 74, 76: Communication path 77: Pressure take-out boat Applicant: Chikunor Co., Ltd. 3 Figure 3

Claims (2)

[Claims] (1) Voltage Maroku: &; 1: Main 1: A variable AC power supply, a solenoid coil connected to the AC power supply, an armature movably disposed inside the solenoid coil, and a land. a spool that can come into contact with the armature directly or indirectly through a rigid portion at a first end, a pressure port 1 and a drain port 1, the spool being movable in the axial direction; , a housing that accommodates the land in a state where communication between the pressure boat and the drain boat is cut off; and a land of the spool that has a squeezing effect on the pressure boat and the drain boat! j. a notch formed in the second end of the spool to communicate with each other and to increase the throttling effect when the spool moves toward the second end opposite to the first end; An electromagnetic pressure control valve comprising: a feedback mechanism that feeds back a force corresponding to the pressure of the pressure boat; and the pressure of the pressure boat can be changed by changing power supplied to the solenoid coil. (2) An AC power supply device with variable voltage or current, a solenoid coil connected to the AC power supply device, an armature movably disposed inside the solenoid coil, and a land (M, first A spool facing the armature at an end, a pressure boat and a drain boat, the spool being movable in the axial direction, and the land being connected to the pressure port.
a housing for accommodating the pressure boat and the drain boat in a state where the communication between them is cut off from each other; a notch formed to increase the throttling effect when moving toward the opposite second end; and a notch having an elastic deformation capacity smaller than the axial dimension of the notch to connect the first end of the spool and the armature. a vibration absorbing member that is interposed alone or together with a rigid member to reduce vibrations transmitted from the armature to the spool; and a vibration absorbing member that feeds back a force corresponding to the pressure of the pressure boat to the second end of the spool. 1. An electromagnetic pressure control valve, comprising a feedback mechanism, and capable of changing the pressure of the pressure boat by changing the power supplied to the solenoid coil.