JP2005308090A - Solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid valve for suppressing the turbulence of a flow rate and that of control pressure. <P>SOLUTION: A poppet valve provided at the tip of a rod 5 comprises a body section 51 and a tip section 52. The body section 51 shows a function for closing a valve by being seated at a seat 6 and for opening the valve by separating from the seat 6. The tip section 52 shows a function for straightening the flow of fluid by entering the inside of a through hole 61 provided at the seat 6. Then, the outer wall surface of any of the body section 51 and the tip section 52 is composed of a tapered surface, and the taper angle of the outer wall surface at the tip section 52 is larger than that of the outer wall surface at the body section 51. The outer wall surfaces of the body section 51 and the tip section 52 are connected and no steps are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solenoid valve.

  In general, a solenoid valve is widely used to perform flow rate control and fluid pressure control. A solenoid valve using a so-called linear solenoid that controls the attraction force of the plunger in accordance with the amount of current supplied to the coil is known. According to the solenoid valve using this linear solenoid, the energization amount to the coil and the fluid pressure can be made proportional. Such a solenoid valve can be suitably used, for example, for clutch hydraulic pressure control of an electronically controlled automatic transmission.

  A solenoid valve according to a conventional example will be described with reference to FIGS. FIG. 11 is a schematic cross-sectional view of a solenoid valve according to a conventional example. 12 to 14 are schematic cross-sectional views showing how the valve portion of the conventional solenoid valve is driven. 12 shows a state in which the valve is completely opened, FIG. 13 shows a state in which the valve is slightly opened, and FIG. 14 shows a state in which the valve is closed. FIG. 15 is a graph showing control pressure characteristics of a solenoid valve according to a conventional example.

  The solenoid valve 100 according to this conventional example includes a plunger 102 that moves in response to energization / non-energization of the coil 101, a rod 103 that moves together with the plunger 102, a poppet valve 103a provided at the tip thereof, and a poppet valve 103a. And a valve seat 104. The solenoid valve 100 includes an input port P1, an output port P2, and drain ports P3 and P4.

  In the solenoid valve 100 configured as described above, when the coil 101 is not energized, the poppet valve 103a is located away from the valve seat 104 (see FIG. 12). In this case, the valve is fully open. Therefore, the fluid flowing in from the input port P1 flows to the output port P2 and is also discharged to the drain ports P3 and P4 through the valve. Therefore, the flow rate of the fluid flowing to the output port P2 is small, and the control pressure (the pressure of the fluid flowing to the output port P2) is also low.

  Next, in a state where the energization amount to the coil 101 is low, the plunger 102 moves to the center post 105 side, and the poppet valve 103a approaches the valve seat 104 (see FIG. 13). In this case, the valve is in a slightly open state. Therefore, the fluid flowing in from the input port P1 flows to the output port P2, and is slightly discharged through the valve to the drain ports P3 and P4. Therefore, the flow rate of the fluid flowing to the output port P2 increases, and the control pressure (pressure of the fluid flowing to the output port P2) also increases.

  When the energization amount to the coil 101 is a certain level or more, the plunger 102 moves to the center post 105 side, and the poppet valve 103a is seated on the valve seat 104 (see FIG. 14). In this case, the valve is completely closed. Therefore, the fluid flowing in from the input port P1 flows only to the output port P2. Therefore, the flow rate of the fluid flowing to the output port P2 is equal to the flow rate of the fluid flowing in from the input port P1. Further, the control pressure becomes equal to the original pressure (pressure of the fluid flowing in from the input port P1).

As described above, according to the solenoid valve 100 using the linear solenoid, the flow rate and pressure of the fluid flowing out from the output port P2 can be controlled by adjusting the energization amount to the coil 101.

  In the solenoid valve 100 using such a linear solenoid, the control pressure may be disturbed when the drain amount is small (the valve is slightly opened). FIG. 15 shows the control pressure characteristics of the solenoid valve 100 configured as described above. This figure shows the relationship between the energization amount to the coil 101 and the control pressure (the pressure of the fluid (here, oil) flowing out from the output port P2). As can be seen from the figure, oil vibration (a state in which the control pressure (hydraulic pressure) is disturbed and vibrates) may occur in the portion indicated by P.

  Such oil vibration occurs when the valve itself causes self-excited vibration. The self-excited vibration is generally caused by applying a certain force (for example, hydraulic vibration or vibration of the solenoid valve itself). Such self-excited vibration is continuously generated or stopped due to the influence of the environment and the shape of the solenoid valve. Moreover, the following cases are mentioned as an environment in which such self-excited vibration is likely to occur. That is, (1) when the control fluid is in a high temperature state (a state where the viscosity of the control fluid is lowered), (2) when the pulsation of the original pressure is large, and (3) when the movement of the valve (poppet valve) is large. (3) (A) Normally, the solenoid valve is driven by pulse width modulation control (PWM control). When the drive frequency is lowered, (B) when the sliding resistance of the valve is reduced, (C) It tends to occur due to the influence of the resonance frequency of the valve.

  In the solenoid valve 100 according to the conventional example, when the change in the opening area is large when the valve is shifted from the closed state to the open state, or when the valve is slightly opened, the drain is passed through the valve. It is considered that the self-excited vibration is difficult to be settled and the control pressure is greatly disturbed because the flow of the fluid discharged to the ports P3 and P4 is not smoothly performed.

Patent Document 1 discloses a configuration in which a truncated cone-shaped part is provided at the tip of the valve body and this part enters the valve hole of the valve seat. However, even in this conventional configuration, the flat portion of the valve element is seated on the valve seat. Therefore, in a state where the valve is slightly opened, the fluid flow is not smoothly performed as in the conventional example. Therefore, in a state where the valve is slightly opened, the valve body is easily affected by the fluid pressure (blocking the fluid flow and easily changing the dynamic pressure to the static pressure). From the above, even in the technique disclosed in Patent Document 1, it is difficult to suppress the disturbance of the control pressure. In addition, as a related known technique, those disclosed in Patent Documents 2 to 4 can be cited.
Japanese Utility Model Publication No. 5-90057 JP-A-6-241333 JP 2001-116126 A Japanese Patent No. 2832283

  One of the objects of the present invention is to suppress the disturbance of the flow rate and the disturbance of the control pressure.

  Another object of the present invention is to reduce the size of the apparatus.

  The present invention employs the following means in order to solve the above problems.

That is, the solenoid valve of the present invention is
In a solenoid valve that can control the stroke of the plunger by the amount of current flowing to the coil,
With a poppet valve that moves with the plunger,
The poppet valve
A body part that closes the valve by sitting on the valve seat or opens the valve by separating from the valve seat;
A tip portion provided on the tip side of the body portion, and
Each of the body part and the tip part is provided with an outer wall surface that tapers, and the tip part is tapered more than the body part.

  According to the configuration of the present invention, the valve is slightly opened by providing the tip portion with the outer wall surface tapering on the tip side of the body portion and the shape of the body portion and the outer wall surface of the tip portion being tapered. Even in this state, the flow of fluid flowing toward the open valve is rectified. Further, by providing the tip portion, a change in the opening area can be reduced when the valve is shifted from the closed state to the open state. From the above, disturbance of the flow rate of the fluid flowing toward the valve can be suppressed, and disturbance of the control pressure can also be suppressed. Furthermore, since the tip portion has a greater degree of taper than the body portion, the entire length of the poppet valve is not so long. Therefore, the stroke of the poppet valve required for control is not so long, and the entire solenoid valve can be downsized. Furthermore, since the tip portion has a greater degree of taper than the body portion, the effect of the fluid pressure in the flow path on the input side and the control side becoming excessively high due to the following usage mode is effective. Can be prevented. That is, by using the solenoid valve of the present invention, the control is performed within the range from the state where the body portion is seated on the valve seat to the boundary portion between the body portion and the tip portion reaching the opening end surface of the valve seat. . And when the fluid pressure in the flow path on the input side or control side exceeds a certain level or when control is not performed, the boundary between the body and the tip will pass over the open end face of the valve seat at appropriate times. Move the poppet valve. Thereby, since the tip portion has a greater degree of taper than the body portion, the rate of increase in the opening area of the valve can be increased. Therefore, the rate of increase of the flow rate of the fluid passing through the valve can be increased, and the fluid pressure in the flow path on the input side or the control side can be reduced early. Thereby, it can prevent that the fluid pressure in the flow path of an input side or a control side becomes high too much.

  Here, the outer wall surfaces of the body portion and the tip portion are preferably connected to each other.

  With this configuration, when the vicinity of the boundary between the body portion and the tip portion passes through the vicinity of the valve seat, the opening area does not change abruptly.

  Further, the outer wall surface of the body part and the tip part may be a tapered surface or a spherical surface.

  In addition, said each structure can be employ | adopted combining as much as possible.

  As described above, according to the present invention, it is possible to suppress the disturbance of the flow rate and the disturbance of the control pressure. Further, the apparatus can be downsized.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

  With reference to FIGS. 1-8, the solenoid valve which concerns on Example 1 of this invention is demonstrated.

<Overall description of solenoid valve>
With reference to FIG. 1, the whole solenoid valve based on Example 1 of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of a solenoid valve according to Embodiment 1 of the present invention. The solenoid valve 1 according to the present embodiment includes a coil 2 that generates a magnetic field when energized, a plunger 3 that is magnetically attracted to the center post 4 by forming a magnetic circuit with the magnetic field generated by the coil 2, and a plunger 3, a rod 5 that moves together with the plunger 3, and a poppet valve provided at the tip of the rod 5. The solenoid valve 1 further includes a valve seat 6 of a poppet valve, a side ring 7 that is a magnetic member provided so as to surround the periphery of the plunger 3, a valve body 8 that is integrally provided with a bobbin 81, and A bottom cylindrical case 9 is provided. A through hole 91 is provided at the bottom of the case 9.

  In addition, the solenoid valve 1 is provided between a spring 10 that regulates the position of the plunger 3, a bearing 11 of the plunger 3, a bearing 12 of the rod 5, the side ring 7, and the center post 4. The magnetic path is detoured to the plunger 3 side so that the magnetic path is not directly connected between them, and a part of the magnetic circuit is configured, and the solenoid valve 1 is mounted at a desired mounting position. Bracket 14 and seal rings 15 and 16 for preventing fluid from leaking from a predetermined flow path.

  The plunger 3, the center post 4, the bracket 14, the case 9, and the side ring 7 are made of a magnetic material. When the coil 2 is energized, a magnetic circuit is formed in the order listed or vice versa. As a result, the plunger 3 is magnetically attracted toward the center post 4 side.

  Further, the valve body 8 is configured by a tubular portion 82 on the distal end side of the valve, and a first communication hole communicating with the inside of the tube on the distal end side and the other end side of the tubular portion 82 from the valve seat 6. 83 and a second communication hole 84 are provided. The valve seat 6 provided inside the valve body 8 is provided with a through hole 61. When the body portion 51 of the poppet valve provided at the tip of the rod 5 is seated on the valve seat 6, the through hole 61 is closed and the valve is closed, and the body portion 51 is separated from the valve seat 6. Then, the through hole 61 and the second communication hole 84 communicate with each other and the valve is opened.

<Details of poppet valve>
The poppet valve provided at the tip of the rod 5 includes a body portion 51 and a tip portion 52. The poppet valve can be formed integrally with the tip of the rod 5 or can be attached to the tip of the rod 5 as a separate part. The body portion 51 of the poppet valve exhibits a function of closing the valve by being seated on the valve seat 6 and opening the valve by being separated from the valve seat 6. On the other hand, the distal end portion 52 provided on the distal end side relative to the body portion 51 does not contact the valve seat 6. The distal end portion 52 has a function of rectifying the flow of the fluid by entering the inside of the through hole 61 provided in the valve seat 6. The tip 52 also exhibits a function of reducing a change in the opening area with respect to the movement of the poppet valve.

  In the present embodiment, the outer wall surface of each of the body portion 51 and the distal end portion 52 is a tapered surface and has a tapered shape. And the taper angle of the outer wall surface in the front-end | tip part 52 is larger than the taper angle of the outer wall surface in the fuselage | body part 51, and the former has a greater degree of taper. Further, the outer wall surfaces of the body portion 51 and the tip portion 52 are connected to each other, and no step is provided.

<Examples of using solenoid valves>
An example of the use of the solenoid valve 1 configured as described above will be described with reference to FIGS. FIGS. 2-4 is typical sectional drawing which shows the mode of the drive of the valve | bulb part in the solenoid valve based on Example 1 of this invention. 2 shows a state where the valve is completely opened, FIG. 3 shows a state where the valve is slightly opened, and FIG. 4 shows a state where the valve is closed.

  Using this solenoid valve 1, for example, the first communication hole 83 provided in the cylindrical portion 82 is used as an input port, and the opening at the tip of the cylindrical portion 82 is referred to as an output port (hereinafter referred to as a control port as appropriate). ) To control the flow rate of fluid exiting the control port or the fluid pressure. The through hole 91 provided in the bottom of the case 9 and the second communication hole 84 provided in the tubular portion 82 of the valve body 8 function as a drain port for discharging a fluid that does not contribute to control.

  When the coil 2 is not energized, the body portion 51 of the poppet valve is located away from the valve seat 6 (see FIG. 2). In this case, the valve is fully open. Therefore, the fluid flowing in from the input port flows to the output port and is discharged to the drain port through the valve. Therefore, the flow rate of the fluid flowing to the output port is small, and the control pressure (the pressure of the fluid flowing to the output port) is also low.

  Next, in a state where the amount of current supplied to the coil 2 is low, the plunger 3 moves to the center post 4 side, and the tip portion 52 of the poppet valve enters the inside of the through hole 61 of the valve seat 6, and the body portion of the poppet valve. 51 approaches the valve seat 6 (opening end part thereof) (see FIG. 3). In this case, the valve is in a slightly open state. Therefore, the fluid flowing in from the input port flows to the output port and is also slightly discharged to the drain port through the valve. Therefore, the flow rate of the fluid flowing to the output port increases, and the control pressure (pressure of the fluid flowing to the output port) also increases.

  When the energization amount to the coil 2 is a certain level or more, the plunger 3 moves to the center post 4 side, and the body portion 51 of the poppet valve is seated on the valve seat 6 (the open end thereof) (FIG. 4). reference). In this case, the valve is completely closed. Therefore, the fluid flowing in from the input port flows only to the output port. Accordingly, the flow rate of the fluid flowing to the output port is equal to the flow rate of the fluid flowing from the input port. Further, the control pressure becomes equal to the original pressure (pressure of fluid flowing from the input port).

  Further, in the solenoid valve 1 according to the present embodiment, the flow rate and pressure of the fluid flowing out from the output port can be controlled by adjusting the energization amount to the coil 2. That is, the solenoid in the solenoid valve 1 according to the present embodiment is a so-called linear solenoid, and the magnetic attraction force of the plunger 3 with respect to the center post 4 can be linearly controlled in accordance with the energization amount to the coil 2. The position of the plunger 3 is determined by the balance of the pressure of the fluid flowing from the input port, the magnetic attractive force of the plunger 3 toward the center post 4, and the spring force of the spring 10. Therefore, the stroke of the plunger 3 can be controlled linearly by adjusting the energization amount to the coil 2. Thereby, the flow rate and pressure (control pressure) of the fluid flowing to the output port can also be controlled linearly. The solenoid valve 1 configured as described above can be used for pre-pressure control, line pressure control, clutch pressure control, and the like. As a more specific example, it is suitable for clutch hydraulic pressure control of an electronically controlled automatic transmission. Can be used.

<Advantages of the solenoid valve according to this embodiment>
With reference to FIGS. 5-8, the point which the solenoid valve 1 which concerns on a present Example is excellent is demonstrated. FIG. 5 is a graph showing the relationship between the stroke of the poppet valve and the opening area of the valve in the solenoid valve according to the first embodiment of the present invention. FIG. 6 is a graph showing the control pressure characteristics of the solenoid valve according to the first embodiment of the present invention. FIG. 7 is a simplified diagram of the valve portion of the solenoid valve according to the first embodiment of the present invention. FIG. 8 is a graph showing the relationship between the stroke of the poppet valve and the discharge flow rate to the drain port.

  The horizontal axis in the graph of FIG. 5 is the stroke of the poppet valve. That is, the abscissa represents the movement distance that the poppet valve has moved in the direction of opening the valve, with the valve closed being zero. The vertical axis represents the opening area of the valve. That is, the vertical axis is the minimum cross-sectional area of the flow path formed between the poppet valve and the valve seat.

  As can be seen from FIG. 5, the opening area changes linearly until the boundary portion between the body portion 51 and the tip portion 52 passes through the opening end surface of the valve seat 6 (the stroke is from 0 to 0.25). And after the boundary part of the trunk | drum 51 and the front-end | tip part 52 passes through the opening end surface of the valve seat 6, opening area changes to a curvilinear form gently. Here, in the present embodiment, since the distal end portion 52 having a tapered outer wall surface is further provided on the distal end side than the body portion 51, the amount of change in the opening area from the start of opening of the valve is small. Therefore, the change amount of the flow rate discharged to the drain port and the flow rate flowing to the control port is small. Therefore, the flow rate and pressure of the fluid flowing to the control port do not change suddenly. Moreover, since the outer wall surfaces of the trunk | drum 51 and the front-end | tip part 52 are connected, a level | step difference does not arise between the part from which an opening area changes linearly, and the part from which it changes in a curvilinear form. In the case where a step is provided without connecting the outer wall surfaces of the body portion 51 and the tip portion 52, the opening area suddenly increases between a portion where the opening area changes linearly and a portion where the opening area changes linearly. Will result in a step that changes.

  FIG. 6 shows the control pressure characteristics of the solenoid valve 1 according to the present embodiment, and shows the relationship between the amount of current supplied to the coil 2 and the control pressure when a fluid having a source pressure of 0.687 MPa flows from the input port. Yes. As can be seen from the figure, in this embodiment, the control pressure is not greatly disturbed, and a stable control pressure can be realized.

  The reason for this is that, as described above, as described above, the amount of change in the opening area from the beginning of opening of the valve is small, and the control pressure does not change rapidly. Second, in a state in which the tip 52 and the body 51 enter the inside of the through hole 61 of the valve seat 6, the fluid that passes through the valve from the input port side to the drain port side is the tip 52 and the body 51. The poppet valve is less affected by the fluid flow. Further, in this embodiment, the poppet valve is not adversely affected by the flow of fluid because the outer wall surface is rectified by the tapered body portion 51 immediately after the valve starts to open.

  FIG. 7 shows a simplified valve portion of the solenoid valve according to the first embodiment of the present invention. Further, in FIG. 7, a virtual poppet valve 53 in the case where the poppet valve is configured with a single cone having the same apex angle as the taper angle of the body portion 51 is indicated by a dotted line.

  FIG. 8 shows the relationship between the stroke of the poppet valve and the discharge flow rate to the drain port. In the figure, X represents the case of the solenoid valve according to the present embodiment, Y represents the case where the poppet valve is replaced with the virtual poppet valve 53 with respect to the solenoid valve according to the present embodiment, and Z represents the above-described FIG. The case of the solenoid valve which concerns on the prior art example shown is shown.

  As can be seen from Z in FIG. 8, in the case of the solenoid valve 100 according to the conventional example, the discharge flow rate to the drain port is disturbed when the stroke is small, that is, when the valve starts to open. Accordingly, the flow rate of the fluid flowing to the output port is similarly disturbed. The reason why this disturbance occurs is as described in the description of the background art.

In addition, in FIG. 8, a tapered portion is provided at the tip of the poppet valve from X and Y, and this portion enters the inside of the through hole 61 of the valve seat 6, thereby suppressing disturbance of the discharge flow rate to the drain port. I understand that I can do it. And the structure which provides the front-end | tip part 52 with a taper degree larger than the trunk | drum 51 in the front end side rather than the trunk | drum 51 like this Example compared with the case where a poppet valve is comprised with a single cone. When is adopted, the change in the discharge flow rate to the drain port with respect to the stroke increases from the middle. Needless to say, this is because, after the boundary portion between the body portion 51 and the tip portion 52 passes through the opening end portion of the valve seat 6, as shown in FIG. In view of the above, in order to increase the discharge flow rate to the drain port and reduce the flow rate flowing to the output port (reduce the control pressure), it is better to adopt the configuration of this embodiment. The stroke can be small. In other words, the stroke of the poppet valve for realizing the desired control range may be smaller if the configuration of this embodiment is adopted. Therefore, in the case of the solenoid valve 1 according to the present embodiment, it is possible to perform desired control without increasing the overall length, and thus it is possible to reduce the size of the apparatus. Furthermore, since the tip portion 52 has a greater degree of taper than the body portion 51, the fluid pressure (hydraulic pressure) in the flow path (hydraulic circuit) in the input side or the control side can be obtained in the following manner of use. Can be effectively prevented from becoming excessively high. That is, using the solenoid valve 1 according to the present embodiment, a range from the state where the body portion 51 is seated on the valve seat 6 to the boundary portion between the body portion 51 and the tip portion 52 reaching the opening end surface of the valve seat 6. Control is performed within (in FIG. 5, the stroke is within the range of 0 to 0.25). And, when the fluid pressure in the flow path on the input side or the control side becomes a certain level or higher, or when the control is not performed, the boundary portion between the body portion 51 and the tip portion 52 is the opening end surface of the valve seat 6 when appropriate. Move the poppet valve past the. Thereby, since the front-end | tip part 52 has a large taper degree compared with the trunk | drum 51, the increase rate of the opening area of a valve can be raised. Therefore, the rate of increase in the flow rate of the fluid that passes through the valve and is discharged from the drain port can be increased, and the fluid pressure in the flow path on the input side or the control side can be reduced early. Thereby, it can prevent that the fluid pressure in the flow path of an input side or a control side becomes high too much. As described above, since the poppet valve is constituted by the body portion and the tip portion having different degrees of taper, the fluid pressure on the input side and the control side can be released and the fluid pressure can be prevented from becoming excessively high. . Further, as described above, the poppet valve is configured by the tip portion 52 and the body portion 51 having different degrees of taper, and in the process of opening the valve, by increasing the discharge flow rate from the middle to the drain port, In addition, the fluid pressure in the flow path on the control side (pressure in the hydraulic circuit) can be temporarily lowered to quickly adjust the zeroing leveling.

  9 and 10 show a second embodiment of the present invention. In this embodiment, an example in which the shape of the tip portion of the poppet valve is changed with respect to the configuration of the first embodiment. Since other configurations and operations are the same as those in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted. FIG. 9 is a simplified diagram of the valve portion of the solenoid valve according to the second embodiment of the present invention. FIG. 10 is a graph showing the relationship between the stroke of the poppet valve and the opening area of the valve in the solenoid valve according to the second embodiment of the present invention.

  In the present embodiment, as shown in the figure, a configuration in which the outer wall surface of the tip portion 54 is a spherical surface is adopted. Also in this embodiment, the outer wall surface of the distal end portion 54 is tapered, and the distal end portion 54 is more tapered than the body portion 51. Moreover, the outer wall surfaces of the trunk | drum 51 and the front-end | tip part 54 are connected, and the level | step difference is not provided. As can be seen from FIG. 10, the opening area with respect to the stroke also changes gently and smoothly without causing a step in the middle. From the above, also in the case of the present embodiment, the same effect as in the case of the first embodiment can be obtained.

[Others]
As explained so far, the poppet valve is composed of a body part and a tip part, and the shape of the outer wall surface of the body part is composed of a tapered surface in both of the first and second embodiments. In the case of the first embodiment, the shape is a tapered surface, and in the case of the second embodiment, the shape is a spherical surface.

  However, the point is that the outer wall surfaces of the body part and the tip part are both tapered, and the shape is not limited as long as the latter satisfies the condition that the degree of taper is larger. Typical examples of the tapered shape include a tapered surface and a spherical surface as in the above embodiments. These combinations include: (1) when the outer wall surface of the body and the tip are both tapered surfaces; (2) when both outer wall surfaces are spherical surfaces; and (3) the former outer wall surface is tapered. In the case where the latter outer wall surface is a spherical surface, there are four types: (4) the former outer wall surface is a spherical surface and the latter outer wall surface is a tapered surface.

  (1) is a case corresponding to the first embodiment. In this case, the above condition is satisfied if the taper angle of the tapered surface of the tip is made larger than that of the body. In the case of (2), the above condition is satisfied if the radius of curvature of the spherical surface of the tip portion is made larger than that of the body portion and these outer wall surfaces are smoothly connected. (3) is a case corresponding to the second embodiment. In this case, a tip portion having a spherical outer wall surface is provided on the inner side of the virtual cone having the same apex angle as the taper angle of the body portion, and the outer wall surfaces are smoothly connected to each other. If so, the above condition is satisfied. In the case of (4), the above condition is satisfied as follows. That is, it is assumed that the cone has a bottom surface that is a circle at the boundary between the body portion and the tip portion, and the generatrix is tangent to the spherical surface of the body portion. And the taper angle of the taper surface of a front-end | tip part is larger than the vertex angle of the said cone, and what is necessary is just to connect smoothly the outer wall surface of a trunk | drum and a front-end | tip part.

  Thus, each combination can be used as appropriate. Of course, it is also conceivable to apply a shape other than a tapered surface or a spherical surface as the tapered shape.

  Moreover, in the description so far, the outer wall surface of the trunk | drum and the front-end | tip part was connected, and the structure in which the level | step difference was not provided was shown. This is because, as described above, when a step is provided, a step is generated in the change in the opening area with respect to the stroke. However, a slight step may be provided between the outer wall surfaces of the body portion and the tip portion as long as no substantial problem occurs in the control.

FIG. 1 is a schematic cross-sectional view of a solenoid valve according to Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view showing how the valve portion of the solenoid valve according to the first embodiment of the present invention is driven. FIG. 3 is a schematic cross-sectional view showing how the valve portion of the solenoid valve according to the first embodiment of the present invention is driven. FIG. 4 is a schematic cross-sectional view showing how the valve portion of the solenoid valve according to the first embodiment of the present invention is driven. FIG. 5 is a graph showing the relationship between the stroke of the poppet valve and the opening area of the valve in the solenoid valve according to the first embodiment of the present invention. FIG. 6 is a graph showing the control pressure characteristics of the solenoid valve according to the first embodiment of the present invention. FIG. 7 is a simplified diagram of the valve portion of the solenoid valve according to the first embodiment of the present invention. FIG. 8 is a graph showing the relationship between the stroke of the poppet valve and the discharge flow rate to the drain port. FIG. 9 is a simplified diagram of the valve portion of the solenoid valve according to the second embodiment of the present invention. FIG. 10 is a graph showing the relationship between the stroke of the poppet valve and the opening area of the valve in the solenoid valve according to the second embodiment of the present invention. FIG. 11 is a schematic cross-sectional view of a solenoid valve according to a conventional example. FIG. 12 is a schematic cross-sectional view showing a driving state of a valve portion in a solenoid valve according to a conventional example. FIG. 13 is a schematic cross-sectional view showing a driving state of a valve portion in a solenoid valve according to a conventional example. FIG. 14 is a schematic cross-sectional view showing a driving state of a valve portion in a solenoid valve according to a conventional example. FIG. 15 is a graph showing control pressure characteristics of a solenoid valve according to a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solenoid valve 2 Coil 3 Plunger 4 Center post 5 Rod 51 Body part 52 End part 53 Virtual poppet valve 54 End part 6 Valve seat 61 Through-hole 7 Side ring 8 Valve body 81 Bobbin 82 Cylindrical part 83 1st communicating hole 84 1st 2 communication holes 9 Case 91 Through-hole 10 Spring 11 Bearing 12 Bearing 13 Spacer 14 Bracket 15, 16 Seal ring

Claims (3)

In a solenoid valve that can control the stroke of the plunger by the amount of current flowing to the coil,
With a poppet valve that moves with the plunger,
The poppet valve
A body part that closes the valve by sitting on the valve seat or opens the valve by separating from the valve seat;
A tip portion provided on the tip side of the body portion, and
The body part and the tip part are both provided with a tapered outer wall surface, and the tip part has a greater degree of taper than the body part.   The solenoid valve according to claim 1, wherein an outer wall surface of the body portion and the tip portion are connected to each other.   The solenoid valve according to claim 1 or 2, wherein the outer wall surface of the body portion and the tip portion is a tapered surface or a spherical surface.

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