JPS58156784A - Pulse-hydraulic converter - Google Patents

Abstract

PURPOSE:To limit the working range of a gap between a core and a plunger, generate a constant force irrespectively of the displacement of an attracted part and contrive to reduce the size of a valve, by using the titled converter for an oil pressure controlling solenoid valve or the like. CONSTITUTION:The pressure inside a pressure chamber 14 is determined through the opening of a pressure inlet port 12 and a pressure outlet port 11 by sliding a pilot spool 9 leftwards or rightwards, thereby balancing the pressure with the resultant force of a spring force exerted on the spool 9 and a magnetic attracting force. The relationship between the gap between the plunger 8 and the core 7 and the attracting force is evaluated as linear by limiting the working range of the gap, and the attracting force and the force of a spring 5 reacting against the attracting force are equalized selecting the rigidity of the spring 5, thereby enabling to generate a force independently of the gap. Accordingly, the oil pressure can be set only in response to an exciting current, and the attracting force can be utilized effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solenoid valve for oil pressure control in an automatic transmission for automobiles, and is a pulse/hydraulic conversion valve suitable for obtaining oil pressure proportional to the duty ratio of a pulse signal that drives the solenoid valve. Regarding.

Conventionally, a spool valve is often used to control oil pressure, but this basically adjusts the oil pressure ti111 so that the force applied to both ends of the spool valve is equal. Usually a hydraulic system at one end, an external force at the other end,
For example, the oil pressure is controlled by using spring force, mechanical operating force, or suction force of a solenoid valve, and combining these forces with the oil pressure by about 9 degrees.

When using the attraction force of a solenoid valve as an external force, the attraction force can be changed by the excitation current, and the hydraulic pressure can be controlled with the current, simplifying the entire control device. I can do it.

However, even when a negative excitation current is supplied, the suction force changes as the spool (suction section) moves, making it difficult to accurately control the hydraulic pressure using the excitation current.

In order to keep the suction force constant regardless of the movement of the spool (suction part), the shape of the suction part can be optimized to achieve Loe performance, but in this case, the suction power must be sacrificed. However, the disadvantage is that the solenoid valve itself becomes larger in size.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a small-sized electromagnetic valve that can generate a large amount of force regardless of the amount of movement of a suction part.

By evaluating the relationship between the gap in the solenoid valve and the suction force as primary by limiting the range of use of the gap, and by selecting the spring constants t- and a of the springs that repel this suction force, This was an attempt to generate a force unrelated to Sky NK.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of the apparatus.

The main spool 13 has two pressure inlets 24 and 25, the pressure inlet 24 is provided with a supply hydraulic pressure 20, and the pressure inlet 25 is connected to a drain 21.

As the spool 13 slides from side to side, the pressure in the pressure chamber 13a is determined, and since the pressure chambers 13a and 23 are connected by a communication path 13b, the pressure value is
It is stabilized and determined at a place where the pressure of E force 14 is equal. 22 is a furnace control hydraulic pressure outlet, the pressure of which is determined by the pressure chamber 14.

Similarly, the pilot spool 9 also slides from side to side.
The pressure in the pressure chamber 14 is determined by the vertical opening of the pressure inlet 12 and the pressure outlet 11, and the spring force acting on the pilot spool 9, the resultant force of the magnetic iron attraction force, and the pressure at this time are balanced. That is, the pressure of the pilot spool 90 surface flRt8t% pressure chamber 14 is changed to PC% spring 5.
The spring force k Fsv is the magnetic attraction force F, 1
Then, at the equilibrium position, 8p-Pc = Fat F-g """""
...(1), and the pressure Pc in the pressure chamber 14 is Pcm-(Fat F--g) ...old...
...(It becomes smell F.

On the other hand, when an excitation current is applied to the coil 3, the main magnetic circuit 2
constitutes a series of closed loops including a core 7, a case 4, and a granger 8, as shown in FIG.

When a magnetic flux passes through the gap between the core 7 and the plunger 8, an attractive force is generated, and this force is expressed as a function of the excitation current I.・
It can be expressed as...dan...former...(3).

Also, suction force F, 6. is also affected by the amount of air gap between the plunger 8 and the core 7, and exhibits a characteristic like %@2 diagram 4131 in this example. That is, it can be seen that the suction force decreases primarily in the gap used. (Direct #32) Now, what if the gap length and spool travel distance are l? ,,,=Kt ・・・・・・・・・・・・
It is possible to assume a constant KK that satisfies (4).

If we choose a spring 5 with a spring constant that is too slow, the equation of balance in equation (2) becomes "K l m/
S p ・・・・・・・・・・・・・・・・・・
...(5) here! , is the initial strain of the spring 5. Therefore, the pressure Pa in the pressure chamber 14, which is the output oil pressure, can be determined only by the exciting current.

゛ Generally, the constant in equation (4) includes the plunger 5
By making the angle of inclination of the gap with the core 7 small with respect to the axial direction, it becomes smaller, and the vertical axis 3 in FIG.
2, but the space used is almost flat. Therefore, the suction force can be obtained regardless of the gap used. However, the suction force at this time is smaller than when the inclination angle of the gap between the plunger 5 and the core 7 is increased. First, in order to meet the required suction force, the vibration capacity (shape, power consumption) of the solenoid valve must be increased.

According to the present invention, the spring constant of the spring 5 is set to an appropriate 1.
By setting it to 1, regardless of the amount of spool movement,
Since the suction force can be set and a large suction force can be obtained, the oil pressure can be determined only by electric current, and a compact electromagnetic valve can be provided.

According to the present invention, the attraction force that is independent of the gap length can be reduced, so the advantage lies in controlling the hydraulic pressure only with respect to the excitation current.

In addition, since the suction force can be fully utilized, it is effective in downsizing.

[Brief explanation of the drawing]

The first section is a # side view of the device, and the second section is a graph showing performance.

Claims (1)

[Claims] 1. A solenoid valve that supplies an excitation current to a coil and generates a magnetic field to apply an attraction force to an attraction part, slide a spool valve coupled to the attraction part, and change the output oil pressure of the spool valve. , said - placed after the pool valve, 1I
In a pulse hydraulic conversion device having a pressure control valve that controls hydraulic pressure to a pressure equivalent to the output hydraulic pressure, the pulse-hydraulic conversion assumes that the suction force acting on the suction part and the stiffness of the spring are equalized. Device.