JPH02296082A - Fluid controlling solenoid valve - Google Patents

Abstract

PURPOSE:To control the pressure of a fluid linearly against the current applied to a drive source by forming a ring groove at a first port, a communicating hole at a spool and a recessed part, so shaped as to change in the nonlinear state, at the peripheral surface of a first land part, and feeding/discharging the fluid to/from a valve chamber through an overlapped part between the recessed part and the ring groove. CONSTITUTION:A ring groove 2b communicated with a supply port 3 is formed at the inner wall of a cylinder hole 2a. A spool 6 is a magnetic body with a first and a second land parts 8 formed at both ends, and its center part is formed to have a smaller diameter than the land parts 8. The first land part 7 is provided with a recessed part 7c at its peripheral surface facing the ring groove 2b, and this recessed part 7c is opened to an end face 7b on the small diameter side of the spool 6. The peripheral surface of the recessed part 7c is formed into such shape that its opening area changes in the nonlinear state axially from the end face 7b of the first land part 7, and this shape is decided on the basis of its flow characteristic or pressure characteristic. The linear fluid pressure or flow characteristic can be thereby ensured against the current applied to a solenoid coil.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fluid control solenoid valve, and particularly to a pressure proportional control valve used for hydraulic control of automatic transmissions of automobiles, or cooling water control of internal combustion engines. The present invention relates to a fluid control solenoid valve suitable as a flow rate proportional control valve used for.

[Prior Art] Fluid control solenoid valves used in automobiles and the like are broadly classified into those for fluid pressure control and flow rate control, based on their functions and uses. In either case, with recent advances in electronic technology, it is desired to linearly control the pressure or flow rate of the fluid in accordance with the current supplied to the drive source.

As a conventional fluid control solenoid valve for automobiles, for example,
0-73208 discloses a hydraulic control solenoid valve for controlling power steering operation. This uses an electromagnetic solenoid to drive the spool and switch the hydraulic flow path, and an example is described in which one of the three flow paths alternately communicates with the other flow path in response to the sliding of the spool. However, there is no detailed explanation of fluid control.

Japanese Utility Model Application No. 62-177952 discloses an electromagnetic proportional solenoid valve used for hydraulic pressure control of an automatic transmission. This valve body houses a plunger and spool that are driven by a solenoid, and the spool is driven against the biasing force of a spring against the spool to switch between the three ports. It is configured. Regarding this, it is explained that the spool is moved from the neutral position to the left and right by driving the plunger, and the outlet port is alternately switched to an inlet port and a drain port. That is, the outlet port is configured to be blocked at the neutral position of the spool and to selectively communicate with either the inlet port or the drain port. Then, the solenoid is driven by a dithered pulsating drive current, and the amount of restriction between the three ports is changed, resulting in the characteristics shown in Figure 4 of the same publication, that is, the output hydraulic pressure characteristics of a nearly quadratic curve with respect to the solenoid current. It is explained that it can be obtained. In the device described in the publication, the solenoid valve is controlled by another control device, so it is not necessarily necessary for the solenoid valve itself to have linear output hydraulic pressure characteristics with respect to the energizing current. If linear output hydraulic characteristics can be obtained from the valve itself, control becomes easier and there are various advantages.

Furthermore, a proportional electromagnetic pressure reducing valve that adjusts the set pressure according to an electric signal is disclosed in Japanese Patent Application Laid-Open No. 160680/1983, and as a conventional technology, a proportional electromagnetic solenoid that exerts a suction force according to an electric signal is used. A spool valve is disclosed. That is, the solenoid suction force is made constant with respect to the applied current regardless of the stroke of the spool, and a predetermined pressure reducing function is achieved from the balance between the liquid pressure and the suction force against the spool.

Further, in Japanese Utility Model Application Publication No. 61-75563, a flow rate control valve is used to control the flow rate characteristics of two fluid systems, such as the slow system and the main system of a carburetor, so that a predetermined difference in characteristics occurs between the two systems. A control valve is disclosed. In this method, the two edges of the spool, that is, one end face of the land part, are constructed with two inclined planes, and the opening area of one output port is adjusted according to a predetermined deviation in the output characteristics of the other output port. It is designed to be adjustable. In addition, in the graph described in the same publication, the current -
Although it is described that the flow rate characteristics are linear, the reason for this is not clear.

[Problems to be Solved by the Invention] As mentioned above, in automatic transmissions, power steering, etc., it is required to linearly control hydraulic pressure with respect to energizing current, and in speed-sensitive power steering, etc. It is required to linearly control the flow rate with respect to the current. However, none of the above-mentioned conventional techniques can meet this requirement. Japanese Patent Application Publication No. 5
8-160 '680 utilizes the balance between hydraulic pressure and solenoid suction force, so linear control is difficult. Although a graph showing linear characteristics is described in Japanese Utility Model Application Publication No. 61-75563, it is recognized that it simply shows a characteristic deviation between two output ports, and the proof that it is linear is unknown. Even if a linear flow rate characteristic could be obtained with the configuration described in the same publication, it would be necessary to drill a hole in the spool, insert a bottle into it, adjust it with an adjuster, and then fix it as described in the same publication. A rotation prevention mechanism is required. Also, the above-mentioned Utility Model No. 62-
As described in Japanese Patent No. 177952, if the biasing force of the spring is applied to the spool from only one side, the spool must be slid against the biasing force of the spring at the start of driving, and the spool must be slid against the biasing force of the spring at the start of driving. To ensure linear characteristics from immediately after, it is necessary to take measures such as increasing the solenoid current at the start of driving, for example.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluid control solenoid valve that has a simple configuration and can easily linearly control the pressure or flow rate of fluid with respect to the current applied to the drive source from the start of driving.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a cylinder in which at least a first port and a second port are formed in the radial direction, and a cylinder that is slidably accommodated in the cylinder and has at least a first port and a second port formed in the radial direction. Both have a first land portion and a second land portion, and a spool defining a valve chamber in the inner space of the cylinder between the first land portion and the second land portion, and at least the second port is connected to the valve chamber. The solenoid part consists of a valve part that is always in communication with the cylinder, a core disposed in a case connected to the cylinder so as to face the spool, and a solenoid part that includes a solenoid coil wound around the core, and the solenoid part has a small number of solenoid coils wound around the core. in the fluid control solenoid valve that drives the spool by sliding the first land portion, controls communication between the first port and the valve chamber in response to sliding, and controls supply and discharge of fluid into and from the cylinder; a first spring that biases the spool in a direction away from the core; and a second spring that biases the spool in a direction closer to the core; The spring loads of the first spring and the second spring are set so as to form a predetermined gap in the sliding axis direction of the spool, and the spring loads of the first spring and the second spring are set so as to form a predetermined gap in the sliding axis direction of the spool.
An annular groove facing the land portion is formed on the inner surface of the cylinder, a communication hole opening on both end surfaces of the spool and opening into the valve chamber is formed on the spool, and the annular groove is formed on the outer peripheral surface of the first land portion. A recess that communicates with the valve chamber and has an opening area of the outer peripheral surface that changes non-linearly at least along the axial direction, at least through an overlapping portion between the recess and the annular groove. The valve chamber is configured to supply and discharge the fluid to and from the valve chamber.

The spool also includes a first spring that biases the spool in a direction away from the core, and a second spring that biases the spool in a direction that approaches the core. On the other hand, the spring loads of the first spring and the second spring are set so as to form a predetermined gap in the sliding axis direction of the spool, and an opening that communicates with the first port and opens into the cylinder. An opening having a shape in which the opening area into the cylinder changes non-linearly at least along the axial direction is formed on the inner surface of the cylinder, and a communication hole is formed that opens at both end surfaces of the spool and opens into the valve chamber. The first land portion is formed on the spool, and is arranged so that the first land portion overlaps with the opening portion in response to sliding of the spool, and the flow formed by at least the opening portion and the first land portion is The fluid may be supplied to and discharged from the valve chamber via a passage.

In any of the fluid control solenoid valves described above, it is preferable that the cylinder is provided with a third port that communicates with the valve chamber at all times.

[Function] According to the fluid control solenoid valve described above, when the spool slides inside the cylinder, the first land portion is connected to the first land portion bored in the cylinder.
Open and close ports. When fluid is supplied or discharged into the cylinder through this first port, that is, when it is supplied or discharged, the flow rate and pressure of the fluid within the cylinder fluctuate. Specifically, fluid is supplied into the cylinder through an overlapping portion between an annular groove that communicates with the first port formed on the inner surface of the cylinder and a recess formed on the outer circumferential surface of the first land portion facing the annular groove. Or it will be discharged. In this case, as the spool slides, the area of the overlapping portion, that is, the opening area into the cylinder changes depending on the shape of the recess of the first land portion.

Thereby, the sliding stroke of the spool and the opening area into the cylinder are controlled to have a predetermined relationship.

When the solenoid coil is energized, the core is excited and the spool slides within the cylinder. At this time, the outer sides of both end faces of the spool are always connected to the valve chamber between the first land part and the second land part through the communication hole, and the same fluid pressure is applied to both end faces, so these fluid pressures cancel each other out. will be done. In addition, in the initial position of the spool, the biasing forces of the first spring and the second spring are balanced at a position where a predetermined gap is formed with respect to the inner surface of the cylinder, and the spool is held in a state where it does not move in any direction of the sliding shaft. has been done. Therefore, even when the current applied to the solenoid coil at the start of driving is very small, the spool is easily attracted to the core.

The relationship between the sliding stroke and the opening area is set in accordance with the relationship between the current applied to the solenoid coil and the sliding stroke of the spool, and the recess is formed into a non-linear shape that satisfies this relationship. As a result, the flow rate or pressure of the fluid in the cylinder can be adjusted linearly according to the current applied to the solenoid coil.

Further, according to the fluid control solenoid valve according to the second aspect, an opening communicating with the first port formed on the inner surface of the cylinder;
Fluid is supplied into or discharged from the cylinder through the flow path formed by the land facing this, and as the spool slides, the fluid flows between the cylinder and the first land depending on the shape of the opening of the cylinder. The area of the flow path formed, ie, the opening area into the cylinder changes. Thereby, the sliding stroke of the spool and the opening area into the cylinder are controlled to have a predetermined relationship.

[Embodiments] Hereinafter, preferred embodiments of the fluid control solenoid valve of the present invention will be described with reference to the drawings.

FIG. 1 shows a fluid control solenoid valve according to an embodiment of the present invention, in which a valve section 1 and a solenoid section 10 serving as its driving source are shown.
Consists of. The cylinder 2 of the valve part 1 is a substantially cylindrical body with a flange formed at one end, and the flange is caulked and fixed to the end of the cylindrical case 10a of the solenoid part 10.

A supply port 3, a control boat 4, and a discharge port 5 are bored in the cylinder 2 in the radial direction, and these ports open into the cylinder hole 2a. An annular groove 2b communicating with the supply port 3 is formed in the inner wall of the cylinder hole 2a. A spool 6 is slidably housed in the cylinder hole 2a, and a plug 2C is fitted to the end of the cylinder hole 2a.

The spool 6 has a first land portion 7 and a second land portion 8 at both ends.
It is a magnetic body in which the central part is formed with a smaller diameter than these. Therefore, the valve chamber 9 is located between the small diameter portion between the first land portion 7 and the second land portion 8 and the cylinder hole 2a.
are defined, with a constant control port 4 and a discharge port 5.
is connected to. Note that the supply port 3 is the first port according to the present invention.
The discharge port 5 corresponds to the second port, and the control port 4 corresponds to the third port.

541 The land 117 has a concave portion 7d in the axial direction, and the end surface 7
a faces the stopper 2C. Further, as shown in the front view in FIG. 1a, the first land portion 7 has a recess 7C formed on its outer peripheral surface facing the annular groove 2b.
is open at the end face 7b of the spool 6 on the small diameter side. Therefore, the supply port 3 communicates with the valve chamber 9 via the overlapping portion of the recess 7C and the annular groove 2b. The shape of the recess 7c on the outer peripheral surface is such that the opening area changes nonlinearly in the axial direction from the end surface 7b of the first land portion 7, for example, as shown in FIG. These parts are formed by cold forging, etc. The shape of the concave portion C is determined based on the flow rate characteristics or pressure characteristics described later, and FIG. 1a shows an example thereof.

Communication holes 6a and 6 are provided in the axial and radial directions of the spool 6, respectively.
b are formed, and these communicate with each other. Therefore, the valve chamber 9 is located outside both end surfaces of the spool 6, that is, the first
The concave portion 7d of the land portion 7 communicates with the inside of the solenoid portion 10.

The collar portion of the cylinder 2 is joined to one open end of a cylindrical magnetic case 10a of the solenoid portion 1o. A magnetic base plate Sob is caulked to the other open end of the case 10a, and the base plate 10b
A hollow circular magnetic core 10 is formed in the center of the cylinder.
One end of c is fitted. A resin bobbin 11 having a hollow portion into which the core 10c is fitted and around which the solenoid coil 12 is wound is housed in the case 14)a. A cylindrical spacer 13 is interposed between the hollow part of the bobbin 11 and the core 10c, and the communication holes 6a, 6b of the spool 6 are connected in the spacer 13 between the core 10c and the second land part 8. It is said to be liquid-tight except for core 10c
The other end is formed in a tapered shape, and opposite to this, the end surface of the second land portion 8 of the spool 6 is formed in an inverted tapered shape.

A first spring 16, which is a compression spring, is housed in the hollow portion of the core 10c. This first spring 1
6 is interposed between the bottom surface of the inverted tapered end of the second land portion 8 of the spool 6 and the end surface of the stopper 15 screwed onto the open end of the core 10c, and is configured to move the spool 6 toward the plug body 2c. It is energizing.

On the other hand, the bottom surface of the concave portion ``7.d'' of the first land portion 7 and the stopper 2
A second spring 17, which is a compression spring, is disposed between the spool 6 and the stopper 15, and urges the spool 6 toward the stopper 15. Therefore, the spool 6 is connected to the first and second springs 1
It stops at the position where the spring loads Fsl and Fs2 of each of 6.17 are equal, and this position becomes the initial position. In this embodiment, the end surface 7a of the first land portion and the plug body 2c are
The spring load 1iFs1. Fs2 is set, and the initial position is the position shown in FIG.

When the spool 6 is at its initial position and the first land portion 7 is on the plug body 2c side, the annular groove 2b communicates with the valve chamber 9 through a communication path with the entire opening area of the recess 7C. ,
As the first land portion 7 slides within the cylinder hole 2a and moves toward the opposite side of the plug body 2c, that is, toward the solenoid portion 10, the opening area of the recessed portion 7c to the valve chamber 9 decreases, and the annular groove 2
The communication path between b and the valve chamber 9 is narrowed.

When the first land portion 7 further moves in the direction of the solenoid portion 1o and the end of the recessed portion C on the end surface F a side exceeds the end of the annular groove 2b on the solenoid portion 10 side, the annular groove 2b and the valve chamber 9 are connected. Communication will be cut off.

In the above fluid control solenoid valve, the supply port 3 of the valve part 1 is connected to a fluid pressure source (not shown), and fluid at a predetermined supply pressure Ps (kg/cm2) is supplied through the opening of the recess 7C of the first land part 7. and is supplied into the valve chamber 9 of the cylinder 2. The control port 4 is connected to a control device (not shown), and the fluid pressure in the valve chamber 9 is controlled to a control pressure P c (kg g
/cm2) to the control device.

The discharge port 5 is opened to the atmosphere and has approximately atmospheric pressure Po (kg/
cm').

FIG. 4 shows the operating principle of the valve part 1 of this embodiment, in which the opening area of the recess 7C of the first land part 7 with respect to the valve chamber 9 is As (cm"), and the opening area of the discharge port 5 is Ao ( cm').That is, in this embodiment, As is variable and AO is fixed.
The flow velocity of the fluid at C is expressed as Vs (am/5ee), and the flow velocity at the discharge port 5 is expressed as Vo (cm/5ec). The relationship between these fluid pressures and opening areas is as follows.

First, if the flow rate of the fluid is Qf (am'/5ea), there is a relationship of Qf=As-Vs=Ao.Vo, and this flow rate Qf is expressed as in the following equation.

Qf=AsII s−2g γf=Ao
-c-Po ・2g yf11 threat・(1) Here,
g is the gravitational acceleration, γf is the specific gravity of the fluid, and Po~0. Therefore, Pc=to-Ps/H+ (Ao/As)')...
(2), where K indicates a coefficient.

In this way, the flow rate Qf changes in proportion to the opening area As of the recess 7C, and the relationship between the control pressure Pc and the opening area As is expressed by equation (2).

On the other hand, in the solenoid section 10, the solenoid coil 1
The current 1 (A) applied to the spool 2 and the stroke St (cm) of the spool 6 have a substantially linear proportional relationship as shown in FIG. 5(a). The opening area As of the concave portion 7C of the first land portion 7 for this stroke of the spool 6 is expressed as the flow rate Q.
It is set so that f is inversely proportional to the stroke St of the spool 6, as shown in FIG. 5(b), for example. As a result, the flow rate Qf is inversely proportional to the current I flowing through the solenoid coil 12, as shown in FIG. 5(C).

In addition, as described above, the opening area As of the recess 7C is determined by the stroke St of the spool 6, and the control pressure Pc is determined by the solid line in FIG. Set the relationship to be inversely proportional as shown in . As a result, the current I of the solenoid coil 12
On the other hand, in accordance with the stroke St of the spool 6, which changes as shown by the solid line in FIG. 6(a), the opening area As of the recess 7C changes as shown by the broken line in FIG. 6(b), and the control The pressure Pc changes as shown by the solid line. Therefore, Fig. 6 (
As shown in C), the control pressure Pc is inversely proportional to the current ■. Thus, a fluid control solenoid valve is constructed in which the control pressure Pc changes linearly with respect to the current I of the solenoid coil 12.

In addition, as shown by the dashed line in FIG. 6(a), the stroke St of the spool 6 with respect to the current I of the solenoid coil 12
If it does not change linearly, by adjusting the relationship between the stroke St of the spool 6 and the opening area AS of the recess 7C in FIG. 6(b) as appropriate according to the relationship between the two, The relationship between the current (2) and the control pressure Pc can be made linear as shown in FIG. That is, even if the relationship between the current I of the solenoid coil 12 and the stroke of the spool 6 is not linear due to the characteristics of the solenoid section 10, if the two have a stable relationship, the stroke St of the spool 6 will be
Desired control pressure-current (Pc-I) characteristics can be obtained by appropriately changing the shape of the recess 7C whose opening area changes with respect to the control pressure-current (Pc-I). Similarly, the flow rate-current (Qf-1) characteristic can be set to a desired characteristic by appropriately setting the shape of the recess 7c according to the stroke St of the spool 6. For example, it is possible to set the flow rate characteristic to a desired characteristic. is also possible.

To explain the operation of the fluid control solenoid valve of this embodiment, when the solenoid coil 12 is not energized, the spool 6 is in a position separated from the core 10c due to the difference in spring loads between the first and second springs 16 and 17. That is, the spool 6 is in the initial position shown in FIG.
The opening area communicating with the valve chamber 9 is maximum.

Next, when the solenoid coil 12 is energized and current is supplied, the spool 6 is attracted to the core 10c, and the attraction force F
It stops at a position where i is balanced with the spring load difference between the first and second springs 16 and 17, that is, at a position where Fi=Fsl-Fs2. When the current applied to the solenoid coil 12 is increased, the attraction force F of the spool 6 by the core 10c increases.
i increases, and the spool 6 stops at a position closer to the core 10c. That is, as the current in the solenoid coil 12 increases, the moving distance of the spool 6 in the direction of the core 10c, that is, the stroke of the spool 6 increases, and as the current in the solenoid coil 12 decreases, the stroke of the spool 6 decreases. As a result, FIG. 5(a) or FIG. 6(a)
The stroke-current (St-1) characteristics shown in ) are obtained.

In order to ensure such characteristics in the solenoid part 10, the core 10c is formed into a tapered shape, and the second land part 8 of the spool 6 which functions as an armature is formed.
Various measures have been taken, such as forming it into an inverted tapered shape.
Since these are well known, their explanation will be omitted. However, according to this embodiment, even if the 5t-1 characteristic is not necessarily linear as shown by the dashed line in FIG. 6(a), the shape of the recess 7c of the first land portion 7 can be Since a desired Pc-1 characteristic or Qf-1 characteristic can be obtained by appropriately changing the characteristics, there is no need to take complicated means to obtain a linear characteristic for the solenoid section 10.

As described above, the spool 6 slides in the cylinder hole 2a according to the current applied to the solenoid coil 12, and the opening area of the recess 7c of the first land 7 relative to the valve chamber 9 increases or decreases. That is, when the current applied to the solenoid coil 12 increases, the recess 7c is blocked by the wall surface of the cylinder hole 2a in order from the end surface 7b side of the first land 7, and the opening area of the recess 7c with respect to the valve chamber 9 decreases. 7c exceeds the end of the annular groove 2b on the core 10c side, the flow rate of the fluid in the valve chamber 9 supplied from the supply port 3 through the annular groove 2b and the recess 7c decreases, and the pressure in the valve chamber 9 decreases. is approximately atmospheric pressure. Therefore, the flow rate and pressure of the fluid supplied from the control port 4 to other control devices, that is, the control pressure, are respectively shown in FIG.
) and the solenoid coil 12 as shown in FIG. 6(C).
decreases as the current I applied to increases.

Next, when the current applied to the solenoid coil 12 decreases, the attraction force of the spool 6 by the core 10c decreases, so the spool 6 moves toward the plug body 2c, and the opening area of the recess 7c with respect to the valve chamber 9 increases. The flow rate and control pressure of the fluid supplied to the control port 4 increase as shown in FIGS. 5(C) and 6(C). When the opening area of the concave portion C becomes sufficiently larger than the opening area of the discharge port 5, the $tlJ control pressure of the control port 4 becomes approximately equal to the supply pressure of the supply port 3. In other words, the opening area of the recess 7c is determined by the above-mentioned formula P c = KP s / (1+ (A
.

/AS)'') is set to be greater than or equal to the opening area As that satisfies PcLtPs.

In the operation of the spool 6 described above, no matter which position the first land portion 7 and the second land portion 8 are located, the outer side of both end surfaces of the spool 6, that is, the space outside both land portions, communicates with the valve chamber 9. There is. This valve chamber 9 is always in communication with the control port 4 and the discharge port 5, and although there are fluctuations in the control pressure Pc, the spaces outside both lands have the same pressure. As a result, even if the rain space is a closed space as in this embodiment, the pressures on the spool 6 act to cancel each other out, and since the cross-sectional areas of both land portions are the same, these pressures are eventually canceled out. Therefore, the attraction force Fi by the solenoid coil 12 and the core 10C and the spring load Fsl of the first and second springs 16 and 17,
The stopping position of the spool 6 is determined only by the relationship with Fs2.

In particular, at the start of operation when the current applied to the solenoid coil 12 is small, the spring loads Fsl and Fs2 are approximately equal and the spring load difference (Fsl - Fs2) is approximately zero, so even if the current applied to the solenoid coil 12 is small, the operation is smooth. The drive control of the spool 6 can be started at this time. That is, the spring load difference (Fsl - Fs2) between the first and second springs 16.17 is added, and the second
As shown in the figure, the relationship is proportional to the stroke St of the spool 6.

The fluid control solenoid valve of this embodiment is shown in Fig. 5(c) and Fig. 6(
For example, electronic IJ has the characteristics shown in e) and is used as a proportional pressure control solenoid valve in various devices such as internal combustion engines.
It is installed in the hydraulic control circuit of all automatic transmissions, and f! It is used for various control. Alternatively, the characteristics in Figure 5(C) and the characteristics in Figure 6
If the shape of the recessed portion 7C is set so that the characteristics shown in FIG.

FIG. 3 shows another embodiment of the fluid control solenoid valve of the present invention, in which the diameter of the second spring 17 is the same as the diameter of the first spring 16, and the concave portion of the first land portion 7 Accordingly, the inner diameter of 7d is also reduced compared to that in FIG.

Therefore, in the embodiment of FIG. 1, the second spring 17
has a larger diameter than the first spring 16, and the fluid pressure applied to the spool 6 is reduced by the cross-sectional area difference due to the difference in diameter.
The fluid pressure applied to each end face of the second land portion 8 becomes -. As a result, the spool 6 is connected to the solenoid section 1.
Attraction force Fi due to 0 and the first and second springs 16.1
The drive is controlled only by the relationship with the spring load difference (Fsl - Fs2) of 7.

FIG. 7 shows still another embodiment of the fluid control solenoid valve of the present invention, in which the supply pressure Ps is applied to the control chamber 41 through a throttle 31 having an opening area As fixed on the upstream side of the fluid control solenoid valve 100. It is configured to introduce the fluid into the fluid control solenoid valve 100 and discharge it to the fluid control solenoid valve 100. The fluid control solenoid valve 100 is
Supply port 3 of the fluid control solenoid valve in FIG. control port 4
In addition, ports 51 and 52 are provided in place of the discharge port 5, and the rest of the configuration is the same as that in FIG. This port 51 corresponds to an exhaust port when viewed from the control room 41 side,
The fluid in the control chamber 41 is supplied to the annular groove 2 through this port 51.
b and into the valve chamber 9 through the concave portion 7C of the spool 6, and is discharged from the port 52. Therefore, the fluid on the discharge side of the control chamber 41 is controlled according to the opening area of the recess 7c with respect to the valve chamber 9, which increases or decreases as the spool 6 slides. The operation is substantially the same as that of the embodiment shown in FIG. 1, and the characteristics as shown in FIGS. 5 and 6 can be ensured regarding the fluid in the control chamber 41.

FIG. 8 shows still another embodiment of the present invention, and is a partial sectional view of the annular groove 2b portion of the cylinder 2, and the rest of the structure is the same as the embodiment shown in FIG. 1, so it is omitted. In this embodiment, the cylinder hole 2a is a stepped hole, and an annular groove 2 communicating with the supply port 3 is formed on the inner wall of the large diameter part.
b is formed. A cylinder 21 is fitted into the large diameter portion of the cylinder hole 2a, and an opening 21c facing the annular groove 2b is formed in the side wall thereof, and the frontage portion 21c opens into the cylinder hole 2a. Axial end of cylinder 21 and annular groove 2
A gap is formed between the axial end of the cylinder 21, and the supply port 3 communicates with the cylinder hole 2a through this gap and the opening 21c of the cylinder body 21. The shape of the opening 21c on the outer circumferential surface is such that the opening area changes nonlinearly in the axial direction from the axial end (hereinafter simply referred to as the end), and consists of a portion where it decreases rapidly and a portion where it decreases slowly. . Note that this shape is an example and is not limited to this, and the opening 21c may be formed directly on the side wall of the cylinder 2 by cold forging or the like without providing the cylindrical body 21, and the opening 21c may be covered with the opening 21c. An annular member (not shown) having a supply port 3 may be fitted.

A second cylindrical body 22 is fitted into the large diameter portion of the cylinder hole 2a, and the inner surfaces of these cylindrical bodies 21 and the second cylindrical body 22 are configured to be continuous with the inner surface of the small diameter portion of the cylinder hole 2a. has been done. The spool 6 is slidably housed in the cylinder hole 2a, the cylinder 21, and the second cylinder 22, and a plug 2C is fitted to the end of the cylinder hole 2a.

Further, as in the embodiment shown in FIG. 1, a recess is formed in the first land portion 7, and a second spring 17 is disposed between the bottom surface of the recess and the plug body 2C.

Accordingly, the spool 6 is connected to the first and second springs 16.1.
It stops at a position where the spring loads Fsl and Fs2 of each of the springs 7 are equal, and this position becomes the initial position. In this initial position, the end surface 7b of the first land portion 7 is located at the end of the annular groove 2b, and the space between the end of the cylinder 21 and the end surface 7b of the first land portion 7 is End surface 7a and plug body 2C
A gap is formed between them.

As shown in FIG. 8, when the spool 6 is at its initial position, the annular groove 2b is the gap between the end portion of the cylinder 21 and the end surface 7b of the first land portion 7, and the total opening area of the opening 21c. It communicates with the valve chamber 9 through a communication passage, and when fluid is supplied from the supply port 3 to the annular groove 2b, it is immediately supplied into the valve chamber 9 through the gap and opening 21c, and the fluid is supplied to the valve chamber 9 through the control port 3. Control pressure is output from 4. And the first
As the land portion 7 slides within the cylinder hole 2a and moves toward the opposite side of the plug body 2C, that is, toward the solenoid portion 10, the opening area of the gap to the valve chamber 9 decreases. When the first land portion 7 further slides, the gap is closed, and the opening area of the flow path formed by the first land portion 7 and the opening 21c with respect to the valve chamber 9 decreases, and the annular groove 2b and the valve chamber 9
This means that the communication path between the two will be narrowed down. When the first land portion 7 further moves in the direction of the solenoid portion 10 and the end surface 7 exceeds the end portion of the opening portion 21c on the solenoid portion 10 side, communication between the annular groove 2b and the valve chamber 9 is cut off.

Accordingly, the spool 6 smoothly slides in the cylinder hole 2a from its initial position in response to the current applied to the solenoid coil 12, and the spool 6 slides smoothly in the cylinder hole 2a from its initial position, and the spool 6 slides smoothly between the end of the cylinder 21 and the end surface 7b of the first land portion 7. The opening area of the flow path formed by the gap, the first land portion 7, and the opening portion 21c relative to the valve chamber 9 increases or decreases. This ensures linear fluid pressure characteristics or flow rate characteristics with respect to the current applied to the solenoid coil 12 with good rise characteristics.

[Effects of the Invention] Since the present invention is configured as described above, it has the following effects.

That is, according to the fluid control solenoid valve of the present invention, a recess with a predetermined shape is formed in the first land portion of the spool, or an opening with a predetermined shape is formed in the cylinder to control the sliding stroke of the spool and the movement into the cylinder. The opening area can be set in a predetermined relationship, and the fluid pressure applied to both end faces of the spool can be offset by the communication hole, so the recess or opening can be set in a predetermined relationship between the current flowing to the solenoid coil and the sliding stroke of the spool. By simply forming the solenoid coil into a predetermined shape, linear fluid pressure characteristics or flow rate characteristics can be ensured with respect to the current applied to the solenoid coil. In particular, in its initial position, the spool has opposing first and second springs.
Since it is held by the biasing force of a spring and driven by the application of a minute current to the solenoid coil, good start-up characteristics can be ensured.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of one embodiment of the fluid control solenoid valve of the present invention, Fig. 1a is a partially enlarged sectional view of the cylinder, and Fig. 2 is the same, the spring loads of the first and second springs and the spool. FIG. 3 is a vertical sectional view of another embodiment of the fluid control solenoid valve of the present invention, FIG. 4 is an explanatory diagram showing the principle of operation, and FIG. Figure 5(a) shows the characteristics of the spool stroke (St) and current (1), and Figure 5(b) shows the opening area (As) of the recess into the cylinder and the flow rate (Qf). ) and the spool stroke (sB characteristic diagram, Figure 5 (C) shows the flow rate (Qf)
FIG. 6 is a diagram explaining another operating characteristic of the fluid control solenoid valve according to the above embodiment, and FIG. 6(a) shows the spool stroke (St) and Current (1
), Figure 6(b) shows the opening area of the recess into the cylinder (As), control pressure (Pc), spool stroke (St), control pressure (Pc) and spool stroke (S t). 6(C) is a characteristic diagram of control pressure (Pc) and current (I), FIG. 7 is an overall configuration diagram showing another embodiment of the fluid control solenoid valve of the present invention, and FIG. 8 FIG. 3 is a partial cross-sectional view showing still another embodiment of the fluid control solenoid valve of the present invention. 1... Valve section, 2 cylinders. 2a... Cylinder hole, 2b... Annular groove, 2c...
Plug body. 3... Supply port (first port). 4..., control port (third port). 5... Discharge port (second port). 6... Spool, 7... First land part. 6a, 6b... communicating holes. 7a, 7b, one end surface, 7cm recess. 8...Second land portion, 9...Valve chamber. 10...Solenoid part. 10c...Core, 12...Solenoid coil. 16...341 spring. 7...Second spring, 21...Cylinder body. 1c...opening, 22...second cylindrical body. 1... Aperture, 41... Control room. 1.52...Port. 00...Fluid control solenoid valve patent applicant Aisan Kogyo Co., Ltd.

Claims (3)

[Claims] (1) A cylinder in which at least a first port and a second port are formed in the radial direction, and the first land is slidably accommodated in the cylinder and has at least a first land portion and a second land portion. a spool that defines a valve chamber in the cylinder internal space between the first land portion and the second land portion, a valve portion in which at least the second port always communicates with the valve chamber; The solenoid part includes a core disposed to face the spool and a solenoid coil wound around the core, and the spool is driven in response to energization of the solenoid coil, and the first
In a fluid control solenoid valve in which a land portion controls communication between the first port and the valve chamber in response to sliding and controls supply and discharge of fluid into and out of the cylinder, the spool is moved in a direction separating the spool from the core. a first spring that biases;
a second biasing the spool in a direction approaching the core;
a spring, the spring loads of the first spring and the second spring are set so as to form a predetermined gap in the sliding axis direction of the spool with respect to the inner surface of the cylinder at the initial position of the spool; an annular groove communicating with the first land portion and facing the first land portion is formed on the inner surface of the cylinder; a communication hole opening on both end surfaces of the spool and opening into the valve chamber is formed on the spool; A recess communicating with the valve chamber is formed on the outer peripheral surface of the land portion, and the opening area of the outer peripheral surface changes non-linearly at least along the axial direction, and at least the recess and the annular groove are connected to each other. A fluid control solenoid valve, characterized in that the fluid is supplied to and discharged from the valve chamber through an overlapping portion with the valve chamber. (2) A cylinder in which at least a first port and a second port are formed in the radial direction, and the first land is slidably accommodated in the cylinder and has at least a first land portion and a second land portion. and a spool defining a valve chamber in the cylinder internal space between the second land portion and the second land portion, and at least the second port is always in communication with the valve chamber;
The solenoid part includes a core arranged to face the spool in a case joined to the cylinder and a solenoid coil wound around the core, and drives the spool in response to energization of the solenoid coil. In the fluid control solenoid valve, the first land portion controls communication between the first port and the valve chamber in response to sliding, and controls supply and discharge of fluid into and from the cylinder, the spool being separated from the core. a first spring that biases the spool in a direction toward the core; and a second spring that biases the spool in a direction closer to the core; the first spring and the second spring to form a gap;
an opening that sets a spring load of a spring, communicates with the first port and opens into the cylinder, and has an opening area into the cylinder that changes non-linearly at least along the axial direction; is formed on the inner surface of the cylinder, and a communication hole is formed in the spool that opens at both end surfaces of the spool and opens into the valve chamber, and the first land portion moves into the opening in response to sliding of the spool. A fluid control solenoid valve, characterized in that the fluid is supplied and discharged from the valve chamber through a flow path formed by at least the opening and the first land. . (3) The fluid control solenoid valve according to claim 1 or 2, characterized in that the cylinder is provided with a third port that is always in communication with the valve chamber.