JP2000230660A - Solenoid valve for controlling fluid pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a solenoid valve by compactly constructing a structure of allowing a gap formed on an inner periphery side of a coil of the solenoid valve to communicate with the outside. SOLUTION: A valve housing 32 and a cylindrical stator core 27 are fitted on an inner peripheral side of a cylindrical coil 25, and a movable core 30 is slidably fitted on an inner peripheral side of the stator core 27. Sliding the movable core 30 causes a valve shaft 33 to be moved, whereby causing respective ports 37, 39, 41 of the valve housing 32 to be changed over. The movable core 30 is formed with a communicating path 43 penetrating therethrough in an axial direction thereof. The communicating path 43 allows a gap 42 formed on an inner peripheral side of the coil 25 to communicate with the outside, thereby causing the movable core 30 to be smoothly slid (the gap 42 to be changed in volume). This constitution eliminates the need for forming a communicating groove on an outer periphery surface of the movable core 30, thereby preventing a side gap area of the movable core 30 from reducing, which prevents a magnetic attracting force between the movable core 30 and valve housing 32 from being lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure control solenoid valve provided with a communication passage for communicating a gap on the inner peripheral side of a coil to the outside.

[0002]

2. Description of the Related Art An electromagnetic valve for controlling a fluid pressure such as a hydraulic pressure,
There are various structures. For example, as shown in FIG. 5, a cylindrical stator core 12 and a valve housing 13 serving both as a yoke are fixed to the inner peripheral side of a cylindrical coil 11. A movable core 14 is slidably fitted on one side. In this device, when the coil 11 is energized, the magnetic circuit changes from the stator core 12 to the movable core 14 →
It is formed in a path of the valve housing 13 → the coil housing 16 → the stator core 12, and the magnetic attraction acts between the movable core 14 and the valve housing 13, so that the movable core 14 is attracted to the valve housing 13 side. The valve shaft 15 in the housing 13 moves to the left to switch between a plurality of ports of the valve housing 13.

In this configuration, a gap 17 is formed on the inner peripheral side of the coil 11, and the volume of the gap 17 changes with the movement of the movable core 14. Movement of core 14 (change in volume of gap 17)
Is hindered. Therefore, communication grooves 18 penetrating in the axial direction are formed at a plurality of locations on the outer peripheral surface of the movable core 14, and the communication grooves 18 allow the gap 17 on the inner peripheral side of the coil 11 to communicate with the outside.

[0004]

However, if a plurality of communication grooves 18 are formed on the outer peripheral surface of the movable core 14, the area of the outer peripheral surface of the movable core 14 facing the inner peripheral surface of the stator core 12 (the area of the side gap) ) Has decreased,
Accordingly, the magnetic resistance of the magnetic circuit increases, and the movable core 14
The magnetic attraction between the valve housing 13 and the valve housing 13 is reduced. In order to avoid this, it is necessary to increase the outer diameter of the movable core 14, and as a result, there is a disadvantage that the entire device becomes larger.

The present invention has been made in view of such circumstances, and the object thereof is to provide a compact structure for communicating the gap on the inner peripheral side of the coil to the outside, and to provide an overall apparatus. An object of the present invention is to provide a fluid pressure control solenoid valve that can be downsized.

[0006]

According to another aspect of the present invention, there is provided a solenoid valve for controlling a fluid pressure according to the present invention, which has a cylindrical shape coaxial with a base end of a valve housing accommodating a valve shaft. A coil is provided, a cylindrical stator core is fitted on the inner peripheral side of the coil, and a movable core is provided slidably on the inner peripheral side of the stator core, and the valve shaft is moved by sliding of the movable core. Switch between multiple ports in the valve housing. A communication passage penetrating in the axial direction is formed inside the movable core, and the gap on the inner peripheral side of the coil communicates with the outside through the communication passage, so that the sliding of the movable core (change in volume of the gap) is smooth. To be performed. In this case, since there is no need to form a communication groove on the outer peripheral surface of the movable core as in the related art (FIG. 5), the side gap area of the movable core does not decrease.
Magnetic attraction does not decrease. As a result, even if the outer diameter of the movable core is smaller than before, the same side gap area and magnetic attraction force as before can be secured, and the solenoid valve can be downsized.

The present invention may be configured such that the movable core and the valve shaft are integrated by being fixed or integrally formed. However, the movable core and the valve shaft are separated from each other, and May be held in contact with the movable core. In this way, even if the concentricity of each part is slightly deviated due to an assembly error or a processing error, the movable core and the valve shaft can be freely and independently displaced in the radial direction according to the deviation of the concentricity. And concentricity deviations can be absorbed. For this reason, as compared with a configuration in which the movable core and the valve shaft are integrated, the assembly accuracy and the processing accuracy can be reduced, the assemblability and the workability can be improved, and the movable core slides during operation. Both the resistance and the sliding resistance of the valve shaft can be reduced, and the slidability can be improved.

According to the second aspect of the present invention, in the configuration in which the movable core presses the end face of the valve shaft to slide the valve shaft, when the pressing force acts on the eccentric position with respect to the end face of the valve shaft, An unbalanced load is applied to the shaft, and the unbalanced load tilts the valve shaft, increasing the sliding resistance of the valve shaft and deteriorating the slidability.

As a countermeasure, it is preferable that the opening of the communication passage exposed at the end face of the movable core on the valve shaft side is formed symmetrically with respect to the axis of the valve shaft or the movable core. With this configuration, even when the opening of the communication passage of the movable core partially overlaps the end face of the valve shaft, the position where the pressing force acts on the end face of the valve shaft (the contact position of the movable core) is set at the axial center. As a result, the pressing force acting on the end face of the valve shaft does not become an eccentric load. Thereby, the inclination of the valve shaft due to the unbalanced load can be prevented, and the slidability of the valve shaft can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment (1)] An embodiment (1) in which the present invention is applied to a solenoid valve for hydraulic control of an automatic transmission of an automobile will be described below with reference to FIGS. . First, the overall configuration of the solenoid valve 21 will be described with reference to FIG.
A coil 25 wound around a coil bobbin 23 is housed in the coil housing 22 also serving as a yoke, which is molded with a resin 24. A connector housing 26 is provided outside the coil 25, and the terminal 20 insert-molded in the connector housing 26 and the coil 25 are electrically connected.

A cylindrical stator core 27 is fitted to the inner peripheral right side of the coil 25, and a flange-like flange portion 27a formed integrally with the right end of the stator core 27 is overlapped with the end plate 28 so that the coil 25 Housing 22
Is crimped to the right end. End plate 28
Has a communication hole 29 in the center. A movable core 30 is fitted on the inner peripheral side of the stator core 27 so as to be slidable in the axial direction, and a left side portion of the movable core 30 projects leftward from the stator core 27.

On the other hand, an opening 31 on the left side of the coil housing 22 is provided with a valve housing 32 made of a magnetic material.
The base end (right end) of the valve housing 32 is fitted to the inner peripheral left side of the coil 25, and the right end face of the valve housing 32 faces the left end face of the movable core 30. The valve housing 32 also serves as a yoke, and when the coil 25 is energized, a magnetic circuit is formed in a path of the stator core 27 → the movable core 30 → the valve housing 32 → the coil housing 22 → the stator core 27. The magnetic attraction acts between the movable core 3
0 is sucked into the valve housing 32 side.

A valve shaft 33 is slidably accommodated in the valve housing 32 in the axial direction. The valve shaft 33 is urged toward the movable core 30 (right side) by a spring 34, whereby the valve shaft 3
3 is held in a state in which the right end face of the movable core 30 is in contact with the left end face of the movable core 30, so that both slide integrally in the axial direction. A ring seat 35 is attached to the left end of the valve housing 32 by press fitting or the like.
The ball valve body 36 housed in the inside 5 is in contact with the left end of the valve shaft 33. The valve housing 32 has an input port 3 communicating with the seat portion 35a of the ring seat 35.
7, an output port 39 communicating with the valve body storage chamber 38 of the ball valve body 36, and a seat portion 4 on the right side of the valve body storage chamber 38.
Drain port 4 communicating with valve body storage chamber 38 through 0
1 is formed.

The solenoid valve 11 of this embodiment (1) is a normally-open solenoid valve, and the control of the output pressure of the output port 37 is performed by controlling the coil 25 to be ON / OFF.
When the coil 25 is turned off (when not energized), the spring 3
The valve shaft 33 is urged rightward by the elastic force of 4, and the movable core 30 is pressed and moved rightward by the valve shaft 33. As a result, the ball valve element 36 moves rightward due to the input pressure of the input port 37, and the ball valve element 3
6 is separated from the seat portion 35a of the ring seat 35, the input port 37 communicates with the output port 39, and the ball valve body 36 comes into contact with the seat portion 40 on the right side surface of the valve body storage chamber 38, and the output port 39 and drain port 41
To shut off the flow path.

On the other hand, when the coil 25 is turned on (when energized), a magnetic attractive force acts between the movable core 30 and the valve housing 32, and the movable core 30 is attracted to the valve housing 32 side (left side). . As a result, the valve shaft 33 moves leftward against the spring 34, and the left end of the valve shaft 33 presses and moves the ball valve body 36 leftward. The ball valve body 36 contacts the seat portion 35 a of the ring seat 35 while opening the flow path between the output port 39 and the drain port 41 while being separated leftward from the seat portion 40 on the right side portion of the ring seat 35. , The flow path between the input port 37 and the output port 39 is shut off.

Next, a structure in which the gap 42 formed on the inner peripheral side of the coil 42 communicates with the outside will be described. Movable core 3
A communication passage 43 penetrating in the axial direction is formed in the 0 axis portion. The outer diameter of at least the left end of the communication passage 43 is formed smaller than the outer diameter of the valve shaft 33, and the communication passage 43 and the valve shaft 33 are formed coaxially. Valve shaft 33 of movable core 30
On the side end surface (left end surface), the opening 2 of the communication passage 43 is formed.
The two recesses 44 are formed so as to communicate with the communication passage 43. Each recess 44 is, as shown in FIG.
3 is formed in the same shape at a position symmetrical with respect to the axis,
In addition, a part of each of the recesses 44 protrudes outside the contact surface of the valve shaft 33 and communicates with the gap 42 on the inner peripheral side of the coil 25. The gap 42 is a gap surrounded by the movable core 30, the stator core 27, the coil bobbin 23, the valve housing 32, and the valve shaft 33.

Since the volume of the gap 42 changes with the movement of the movable core 30, if the gap 42 is in a closed state, the movement of the movable core 30 (change in the volume of the gap 42) is hindered.

In this respect, in this embodiment (1), the coil 2
The gap 42 on the inner peripheral side of the communication path 5 communicates with the outside through the path of the concave portion 44 of the movable core 30 → the communication path 43 → the communication hole 29 of the end plate 28 (hereinafter referred to as “communication path”). Therefore,
When the coil housing 22 of the solenoid valve 21 is immersed in oil, the oil flows into the gap 42 on the inner peripheral side of the coil 25 from the communication path, and the gap 42 is filled with oil and the movable core The oil in the gap 42 on the inner peripheral side of the coil 25 freely enters and exits through the communication path with the movement of the 30 (change in the volume of the gap 42), and the oil in the gap 42 hinders the movement of the movable core 30. There is no. When the coil housing 22 of the solenoid valve 21 is installed in the air, the coil 2
5 is communicated with the atmosphere via the communication path, and the air in the gap 42 freely enters and exits via the communication path as the movable core 30 moves, and the air in the gap 42 is movable. The movement of the core 30 is not hindered.

Moreover, in this embodiment (1), since the communication passage 43 is formed inside the movable core 30, it is necessary to form a communication groove on the outer peripheral surface of the movable core 30 as in the related art (FIG. 5). Therefore, the side gap area of the movable core 30 does not decrease, and the magnetic attraction does not decrease. As a result, the movable core 3
Even if the outer diameter of 0 is smaller than before, the same side gap area and magnetic attraction as before can be secured,
The electromagnetic valve 21 can be downsized.

Further, in the embodiment (1), the movable core 3
Since the valve shaft 33 and the valve shaft 33 are separated from each other, even if the concentricity of each part is slightly shifted due to an assembly error or a processing error, the movable core 30 and the valve shaft 33 are individually and independently controlled in accordance with the deviation of the concentricity. Can be freely shifted in the radial direction,
Thereby, the deviation of the concentricity can be absorbed. Therefore, as compared with a configuration in which the movable core 30 and the valve shaft 33 are integrated, assembly accuracy and processing accuracy can be relaxed, assemblability and processability can be improved, and the movable core 30 during operation can be improved. And the sliding resistance of the valve shaft 33 can be reduced, and the slidability can be improved.

However, the present invention may have a structure in which the movable core 30 and the valve shaft 33 are integrated by being fixed or integrally formed. Even in this case, the intended object of the present invention can be sufficiently achieved. .

In this embodiment (1), the movable core 3
0, two concave portions 44 exposed on the end face on the valve shaft 33 side.
Since the (opening of the communication passage 43) is formed symmetrically with respect to the axis of the valve shaft 33, even if the concave portion 44 of the movable core 30 partially overlaps the end face of the valve shaft 33,
The position where the pressing force acts on the end face of the valve shaft 33 (the contact position of the movable core 30) is symmetrical with respect to the axis, and the pressing force acting on the end face of the valve shaft 33 does not become an uneven load. Accordingly, the inclination of the valve shaft 33 due to the unbalanced load can be prevented, and the slidability of the valve shaft 33 can be improved.

[Embodiment (2)] FIGS. 3 and 4 show an embodiment (2) in which the present invention is applied to a normally closed solenoid valve 51. FIG.
It will be described based on. A ring 54 accommodating a ball valve body 53 is assembled to the input port 52 formed at the left end portion of the valve housing 32 by press-fitting or the like, and the ball valve body 53 is provided with a first seat portion 55 formed on the valve housing 32.
Open and close. The amount of movement of the ball valve body 53 in the left direction is restricted by a stopper 56 formed on the ring 54.

Further, a second seat portion 57 is formed in the valve housing 32 so as to face the right side of the first seat portion 55, and an output port 58 communicating between the two seat portions 55, 57 is provided between the two seat portions 55, 57. Are formed. The left end of the valve shaft 33 housed in the valve housing 32
5 and 57 and is in contact with the ball valve body 53.
The valve shaft 33 is formed integrally with a tapered valve portion 59 for opening and closing the second seat portion 57 from the right side. A drain port 60 is formed on the right side of the second seat portion 57 of the valve housing 32, and the drain port 60 is formed through a drain passage 61 formed around the outer periphery of the valve shaft 33 in the valve housing 32. The second seat portion 57 communicates with the opening.

In this case, when the coil 25 is turned off (when not energized), the spring force of the spring 34 causes the valve shaft 3
3 is urged rightward, and the movable core 30 is pressed and moved rightward by the valve shaft 33. As a result, the valve portion 59 of the valve shaft 33 is separated rightward from the second seat portion 57 to open the flow path between the output port 58 and the drain port 60, and the input pressure of the input port 52 The flow path between the input port 52 and the output port 58 is blocked by bringing the ball valve body 53 into contact with the first seat portion 55.

On the other hand, when the coil 25 is turned on (when energized), a magnetic attractive force acts between the movable core 30 and the valve housing 32, and the movable core 30 is attracted to the valve housing 32 side (left side). . As a result, the valve shaft 33 is moved leftward against the spring 34, and the valve shaft 33 is moved.
The valve portion 59 is brought into contact with the second seat portion 57 to cut off the flow path between the output port 58 and the drain port 60, and the ball valve body 53 is formed by the left end of the valve shaft 33.
Is separated leftward from the first sheet portion 55 to open a flow path between the input port 52 and the output port 58.

In the embodiment (2), the movable core 3
The communication passage 62 formed inside the valve shaft 0 has a portion on the valve shaft 33 side (left side) branched into two passages 62a.
As shown in FIG. 4, the opening of each passage 62a is formed in the same shape (for example, a circle of the same diameter) at a position symmetrical with respect to the axis of the valve shaft 33, and the opening of each passage 62a is formed. Are protruded outside the contact surface of the valve shaft 33 and communicate with the gap 42 on the inner peripheral side of the coil 25. Other configurations are the same as those in the embodiment (1). In the embodiment (2) described above, the same effect as in the embodiment (1) can be obtained.

In the embodiments (1) and (2), the openings (recesses 4) of the communication passages 43 and 62 on the valve shaft 33 side are provided.
4. Although the passage 62a) is formed at two places, it may be formed at three or more places. In short, it may be formed in the same shape at a position symmetrical with respect to the axis of the valve shaft 33. Alternatively, the communication passage may have only one opening. In short, part of the opening of the communication passage projects outside the contact surface of the valve shaft 33, and the shaft of the valve shaft 33. What is necessary is just to form symmetrically with respect to a heart.

However, if only the intended object of the present invention can be achieved, the opening of the communication passage is not necessarily formed by the valve shaft 33.
May not be symmetrical with respect to the axis of. Also, the present invention
Solenoid valve 2 such as the structure of valve housing 32 and its internal structure
The structures of the components 1 and 51 may be appropriately changed.

In addition, the present invention is not limited to a solenoid valve for hydraulic control of an automatic transmission, but can be applied to solenoid valves of various hydraulic control devices, or can be used for various fluid pressure controls other than hydraulic control. It can be widely applied to solenoid valves.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of a solenoid valve for hydraulic control showing an embodiment (1) of the present invention.

FIG. 2 is a left side view of the movable core as viewed from a section AA in FIG. 1;

FIG. 3 is a longitudinal sectional front view of a hydraulic control solenoid valve showing an embodiment (2) of the present invention.

FIG. 4 is a left side view of the movable core as viewed from a cross section BB in FIG. 3;

FIG. 5 is a vertical sectional front view showing a conventional solenoid valve for hydraulic control.

[Explanation of symbols]

21: solenoid valve, 25: coil, 27: stator core, 3
0: movable core, 32: valve housing, 33: valve shaft, 34: spring, 35: ring seat, 35a ...
Seat part, 36: ball valve element, 37: input port, 39
... output port, 40 ... seat part, 41 ... drain port, 42 ... gap, 43 ... communication path, 44 ... concave part, 51 ... solenoid valve, 52 ... input port, 53 ... ball valve element, 55 ... first seat part 57, a second seat portion, 58, an output port, 59, a valve portion, 60, a drain port, 62, a communication passage, 62a, a passage.

Claims (3)

[Claims] 1. A valve housing having a plurality of ports for controlling fluid pressure, a valve shaft slidably provided in the valve housing, and a cylinder provided coaxially on a base end side of the valve housing. , A cylindrical stator core fitted on the inner peripheral side of the coil, slidably provided on the inner peripheral side of the stator core, and sliding the valve shaft to move the plurality of valve shafts. A fluid pressure, comprising: a movable core for switching a port; and a communication passage formed in the movable core so as to penetrate in the axial direction and communicating a gap on an inner peripheral side of the coil to the outside. Control solenoid valve. 2. The fluid pressure control according to claim 1, wherein the movable core and the valve shaft are separated, and the valve shaft is held in a state in which the valve shaft is in contact with the movable core by a spring. Solenoid valve. 3. The opening of the communication passage, which is exposed at the end face of the movable core on the valve shaft side, is formed symmetrically with respect to the axis of the valve shaft or the movable core. Item 3. An electromagnetic valve for controlling fluid pressure according to Item 2.