JPH0849786A - Solenoid valve - Google Patents

Abstract

PURPOSE:To provide a solenoid valve that can be made compact while having large attracting force with simple constitution. CONSTITUTION:A poppet valve 20 is formed of nonmagnetic metal, and the outer peripheral wall of the flange part 20c of the poppet valve slides with the inner wall of a body 12. A movable element 21 slides with the inner wall of a guide member 22 at the end part outer peripheral wall on the opposite side to the poppet valve 20, and this movable element 21 is energized toward a valve seat 32 by a compression coil spring 16. The outer diameter of the movable element 21 is formed to be slightly smaller than that of the flange part 20c, and the inner diameter of the guide member 22 is smaller than that of the body 12, so that a magnetic side gap 30 is formed between the outer peripheral wall of the movable element 21 and the internal wall of the body 12. The side gap 30 between a magnetic circuit part 12a and the movable element 21 formed of magnetic substance can be reduced, and the outer diameter of the movable element 21 can be enlarged so as to have the effect of increasing attracting force acting upon the movable element 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve for controlling opening / closing of a fluid passage.

[0002]

2. Description of the Related Art As a conventional solenoid valve used for switching a fluid pressure control or a hydraulic control circuit, a cylindrical magnetic member forming a magnetic circuit is formed on the inner wall of a bobbin around which an exciting coil is wound. It is known that a cylindrical guide member made of a non-magnetic material is press-fitted into the inner wall of the member, and the mover is supported by the inner wall of the guide member so as to be slidable in the axial direction.

[0003]

However, in such a conventional solenoid valve, the size obtained by subtracting the plate thickness of the cylindrical magnetic member and the guide member from the inner diameter of the bobbin becomes the upper limit value of the outer diameter of the mover. . Further, the guide member needs to have a plate thickness of at least about 0.3 mm so that it can be press-fitted into the cylindrical magnetic member. Generally, the attraction force exerted on the mover by the magnetic force generated by the exciting current supplied to the coil increases as the outer diameter of the mover increases, and the attraction force of the guide member formed in the radial direction between the cylindrical magnetic member and the mover is increased. The smaller the magnetic side gap including the thickness, the larger the magnetic side gap. However, since the side gap cannot be reduced below the thickness of the guide member, when controlling the high-pressure fluid, it is necessary to increase the inner diameter of the bobbin and increase the outer diameter of the mover when trying to increase the suction force of the solenoid valve. There is a problem that the physical size of the solenoid valve in the radial direction becomes large.

The present invention has been made to solve such a problem, and an object thereof is to provide a solenoid valve having a simple structure, a large suction force, and a small size.

[0005]

A solenoid valve according to claim 1 of the present invention for achieving the above object comprises a body having a cylindrical hole inside, and a bobbin provided in the body and having a coil wound around the body. , A case disposed on the outer circumference of the bobbin, a fixed iron core provided adjacent to one end of the bobbin, and reciprocally housed in the cylindrical hole, and a magnetic force is applied to the fixed iron core side by energizing the coil. A movable part having a movable element to be attracted and a valve element made of a non-magnetic material which is fixed to an end of the movable element on the side opposite to the fixed iron core and is capable of reciprocating in the cylindrical hole, and the fixed iron core. And a biasing means for biasing the movable part on the opposite side, wherein the movable part comprises:
A first sliding portion of the inner peripheral wall of the bobbin, one end side of which is the fixed core side of the mover, and a second sliding portion of which the other end side is slidable on the inner peripheral wall of the cylindrical hole provided in the valve body. Is supported by the inner peripheral wall of the cylindrical hole so as to be capable of reciprocating.

In the electromagnetic valve according to a second aspect of the present invention, the second sliding portion is arranged so as to minimize the magnetic gap formed between the outer peripheral wall of the mover and the inner peripheral wall of the cylindrical hole. The outer diameter of the outer peripheral wall of the mover is slightly smaller than the outer diameter of the movable element. A solenoid valve according to claim 3 of the present invention is a solenoid valve of a three-way valve that controls opening and closing of a fluid passage of three paths by the valve body and a ball valve, and has an accommodating hole capable of accommodating the ball valve. It is characterized in that it is provided with a resin-made supporting member formed in a cylindrical shape having a certain direction, and can be fitted into the body by a slit formed in an axial direction of a side wall of the supporting member.

When the solenoid valve according to a fourth aspect of the present invention is assembled to a mounting portion, it serves as a fluid discharging means from the cylindrical hole of the portion of the body accommodated in the mounting portion to the outside of the mounting portion. A fluid through hole that communicates with the cylindrical hole is formed by penetrating a side wall of the body housed in the mounting portion in the radial direction, and the periphery of the outer wall of the body in which the fluid through hole is formed is located in the mounting portion. It is characterized in that an annular space portion communicating with the fluid passage hole is formed by cutting out to the outside.

[0008]

According to the solenoid valve of the first aspect of the present invention, the movable portion including the mover and the valve element is provided on the first sliding portion provided on the inner peripheral wall of the bobbin and the valve element. Second
Since it is reciprocally supported on the inner peripheral wall of the cylindrical hole of the body at two different locations in the axial direction by means of the sliding part, it is possible to suppress axial runout of the movable part and reduce sliding friction.

According to the second aspect of the present invention, the outer diameter of the outer peripheral wall of the mover is made slightly smaller than the outer diameter of the second sliding portion provided on the valve body. Since the magnetic gap formed by the outer peripheral wall of the mover and the inner peripheral wall of the cylindrical hole can be made as small as possible, the attraction force for attracting the mover can be increased. Further, according to the solenoid valve of the third aspect of the present invention, in the three-way valve which controls opening and closing of the three fluid passages by the valve body and the ball valve, a support member for preventing rattling in the radial direction of the ball valve is provided. By using a resin-made support member formed in a cylindrical shape, it can be constructed at low cost. Further, by providing the supporting member with the slit, the assembling becomes easy.

Further, according to the solenoid valve of the fourth aspect of the present invention, since the periphery of the outer wall of the body in which the fluid passage hole is formed is cut out to the outside of the mounting portion to provide the annular space portion, the mounting is performed. The cylindrical hole and the outside of the mounting portion can communicate with each other through the fluid passage hole and the annular space portion without forming the fluid passage hole in the body side wall outside the portion. Therefore, since the lower end position of the second sliding portion provided on the valve body can be lowered and the axial length of the valve body can be shortened, the physical size of the solenoid valve in the axial direction can be reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a solenoid valve according to a first embodiment of the present invention.
Shown in The solenoid valve 1 is a three-way valve having three paths of fluid inlets and outlets, and a part of the solenoid valve 1 is housed in the mating attachment portion 100. The case 11 of the solenoid valve 1 covers the outer circumference of a portion that is not housed in the mating attachment portion 100. Iron body 12
One of the ends is inserted into the case 11. A cylindrical magnetic circuit portion 12a extending upward in FIG. 1 is provided at an upper end portion of the body 12, and a coil 14 is wound between an inner wall of the case 11 and an outer wall of the magnetic circuit portion 12a. The bobbin 13 is accommodated.

The fixed iron core 15 comprises a cylindrical portion 15a and an annular flange portion 15b extending radially outward from the end of the cylindrical portion 15a. The fixed iron core 15 is inserted into the case 11 from above in FIG. 1 so that the cylindrical portion 15a projects from one end of the bobbin 13 toward the mover 21 described later, and the outer peripheral portion of the flange portion 15b is caulked and fixed by the case 11. There is. An annular portion 15c is formed on the peripheral portion of the cylindrical portion 15a on the magnetic circuit portion 12a side, and a first sliding portion is formed between the annular portion 15c and the magnetic circuit portion 12a so as to come into contact with the inner wall of the bobbin 13. An annular guide member 22 is sandwiched. An air gap 31 is provided between the fixed iron core 15 and the mover 21.
Are formed.

A cylindrical hole 10 for accommodating the poppet valve 20 and the mover 21 and allowing them to slide smoothly is provided inside the body 12 in the axial direction. An oil passage 12b is formed on the opposite side,
A support member 5 to be described later is provided on the oil upstream side of the oil passage 12b.
An oil passage 41 is formed by the inner wall of 0. Oil is supplied to the oil passage 41 from an oil supply source (not shown). An oil passage 42 communicable with the oil passage 12b and the oil passage 41 is formed at a boundary portion between the oil passage 12b and the oil passage 41 so as to penetrate the side wall of the body 12. The oil passage 43 is located at a position where a part of the oil passage 43 is accommodated in the mating attachment portion 100.
The side wall of the body 12 is formed so as to communicate with 2b in the radial direction. The outer peripheral wall of the body 12 in which the oil passage 43 is formed is cut out in an annular shape, and an annular space 10a is formed between the outer periphery of the oil passage 43 and the mating attachment portion 100. The oil passage 11a is formed by partially cutting out the lower end of the case 11 from the axial center toward the outer peripheral direction, and communicates with the oil passage 43 through the space 10a. The oil passage 11a is connected to a drain (not shown). The oil discharged to the drain is the oil passage 12
The oil flows from b to the oil passage 43 and the space 10a radially outward, and then flows upward from FIG. 1 from the space 10a to the oil passage 11a, and again flows radially outward.

The reason for constructing such a bent oil discharge path is as follows. Poppet valve 2
If the axial length (overhang) from the contact portion with the valve seat 32 of 0 to the flange portion 20c forming the second sliding portion is extended to form the oil passage 11a in the upper part of FIG. 1, the oil passage 12b is formed.
Although the oil can be discharged linearly outward from the radial direction, the total axial length of the valve body becomes long, and as a result, the physical size of the solenoid valve 1 in the axial direction becomes large. This problem can be avoided in the discharge route according to the configuration of this embodiment. In addition, since the overhang is shortened and the axial length of the poppet valve 20 is shortened,
When the poppet valve 20 slides on the inner wall of the body 12, axial runout of the poppet valve 20 is suppressed, so the poppet valve 20
The reciprocating motion of can be smoothly performed.

A poppet valve 20 and a mover 2 which are valve bodies.
1 is axially slidably and reciprocally supported by the inner wall of the body 12 and the inner wall of the guide member 22, respectively. The poppet valve 20 is formed of a non-magnetic metal such as austenitic stainless steel, and has a large diameter portion 20a,
Small diameter portion 2 integrally formed at one end of the large diameter portion 20a
0b, a flange portion 20c integrally formed on the outer circumference of the large diameter portion 20a, and the outer peripheral wall of the flange portion 20c slides on the inner wall of the body 12. The other end of the large diameter portion 20a is press-fitted into the mover 21. The mover 21 slides on the inner wall of the guide member 22 at the end outer peripheral wall on the side opposite to the poppet valve 20, and is biased by the compression coil spring 16 toward the valve seat 32. The biasing force of the compression coil spring 16 is
It is set to be larger than the force for pushing the ball valve 51 upward in FIG. 1 by the hydraulic pressure supplied from the oil supply source (not shown) to the oil passage 41. That is, when the coil 14 is de-energized, the ball valve 51 is separated from the valve seat 33 and the oil passage 41 communicates with the oil passage 42.
The solenoid valve 1 is normally open.

As shown in FIG. 2, the outer diameter of the mover 21 is formed slightly smaller than the outer diameter of the flange portion 20c, and the inner diameter of the guide member 22 is smaller than the inner diameter of the body 12 of the mover 21. Since the outer diameter is substantially equal to the outer diameter, the outer peripheral wall of the mover 21 and the inner wall of the body 12 have a magnetic side gap 3
0 is formed. The gap a of the side gap 30 is
It is desirable to form it to 0.02 to 0.2 mm. The smaller the side gap gap a, the stronger the axial suction force acting on the mover, but it is difficult to make it smaller than 0.02 mm in terms of processing, and if it is larger than 0.2 mm, the desired suction force can be obtained. Disappear. Since the gap a is easily processed and has a larger suction force,
It is more desirable to form it to 0.1 mm.

Since the outer peripheral wall of the flange portion 20c, which is a non-magnetic body, and the inner wall of the body 12 slide, the oil in the oil passage 12b is shut off from the mover 21 side.
It is possible to prevent foreign matter contained in the oil in the oil passage 12b, such as iron powder, from entering the mover 21 side which is a magnetic body and being attracted to the mover 21. Therefore, the poppet valve 20 and the mover 21 can smoothly reciprocate.
Further, since the cylindrical magnetic circuit portion 12a covers the outer periphery of the mover 21, it is possible to prevent the magnetic flux from leaking from the mover 21 toward the coil 14 in the direction perpendicular to the axial direction, and thus to the axial direction. A sufficient flow of magnetic flux that acts on the attraction of the mover 21 can be ensured. Annular portion 15c of the fixed iron core 15
Between the magnetic circuit part 12a and the guide member 2 which is a non-magnetic material
2 is sandwiched so that the magnetic flux flowing directly from the magnetic circuit portion 12a to the fixed iron core 15 is blocked, and the magnetic flux generated in the coil 14 is passed from the case 11 to the magnetic circuit portion 12a and the mover 2.
This is because the fixed iron core 15 and the case 11 are passed again. Further, since the guide member 22 can prevent foreign matter from entering between the movable element 21 and the body 12 from the fixed iron core 15 side, the poppet valve 20 and the movable element 21 can smoothly reciprocate.

As shown in FIG. 1, a cylindrical support member 50 made of resin is attached to the other end of the body 12. A ball valve 51 made of a steel ball is housed in an oil passage 41 formed by the inner wall of the support member 50. In the inner wall of the support member 50, a groove-shaped notch 50 as shown in FIGS. 3 and 4 penetrating from the valve seat 33 side in the axial direction.
a is provided in two places, and the ball valve 51 and this notch 50a
Oil can flow through the flow path formed by and.
Following each notch 50a, a slit 50b is formed downward. An annular protrusion 50c is formed on the outer peripheral wall of the lower end of the support member 50. The outer diameter of the protrusion 50c is slightly larger than the inner diameter of the body 12 that houses the support member 50. When the support member 50 is assembled to the other end of the body 12, the gap between the slits 50b is shortened, so that the protrusion 50c is formed.
Can be stored in the body 12, and the projection 50c fits into the annular recess 12c formed in the inner wall of the body 12, so that the support member 50 is locked to the body 12.

Next, the operation of the solenoid valve 1 will be described. (1) When the coil 14 is de-energized, the mover 21, the poppet valve 20 and the ball valve 51 are provided with the compression coil spring 16
1 is urged downward by the urging force of the poppet valve 20.
Sits on the valve seat 32. As a result, the communication between the oil passage 42 and the oil passage 12b is cut off. The ball valve 51 is pushed downward in FIG. 1 by the small diameter portion 20c of the poppet valve 20 and is separated from the valve seat 33. Then the oil passage 4
1 and the oil passage 42 communicate with each other, and control oil is supplied from the oil supply source to the hydraulic control target.

(2) When an exciting current is supplied to the coil 14, the magnetic force generated in the coil 14 causes the air gap 31
The movable element 21 is attracted to the fixed iron core 15 side by the suction force and is lifted upward together with the poppet valve 20 in FIG.
Then, the poppet valve 20 separates from the valve seat 32, so that the high-pressure oil supplied to the hydraulic control target has a low pressure via the oil passage 42, the oil passage 12b, the oil passage 43, the space portion 10a, and the oil passage 11a. The oil is discharged to the drain side, and the oil pressures of the oil passage 42 on the hydraulic pressure control target side and the oil passage 11a on the drain side become equal. Further, the ball valve 51 is biased by the hydraulic pressure supplied from the oil supply source and seats on the valve seat 33, so that the communication between the oil passage 41 and the oil passage 42 is cut off.

FIG. 5 shows the characteristics of the attraction force with respect to the mover diameter and the side gap in the first embodiment in which the cylindrical guide member is not provided and in the conventional example in which the cylindrical guide member is provided.
The side gap of the first embodiment is 0.1 mm. In the conventional example, since the side gap is increased by the plate thickness of the cylindrical guide member, the side gap is 0.3 mm. Comparing the case where the mover diameter is the same, the suction force of the first embodiment having a smaller side gap is larger, and comparing the case of the same suction force, the mover diameter can be made smaller in the first embodiment. In other words, when the same degree of suction force is required, the first embodiment can reduce the size of the solenoid valve in the radial direction as compared with the conventional example.

In the first embodiment, the movable part composed of the poppet valve 20 and the mover 21 slides in the axially different position from the fixed part composed of the body 12 and the guide member 22 which is the first sliding part, Since a guide member made of a cylindrical non-magnetic material that guides the mover slidably in the axial direction is not provided,
Since the sliding frictional force between the movable part and the fixed part is reduced, the side gap 30 between the magnetic circuit part 12a and the mover 21 made of a magnetic material can be reduced, and the outer diameter of the mover 21 can be increased. This has the effect of increasing the suction force that acts on.

Further, in the first embodiment, the flange portion 20c which is the second sliding portion is formed integrally with the poppet valve 20 which is the valve body, so that the sliding portion of the movable portion can be slid without increasing the number of parts of the movable portion. The mobility can be improved. Further, in the first embodiment, by providing the slit 50b in the support member 50 that accommodates the ball valve 51, the support member 50 can be easily inserted into the body 12, and the number of assembly steps can be reduced.

Although the guide member 22 provided on the inner wall of the bobbin 13 is used as the first sliding portion, the inner wall itself of the bobbin 13 may be used. FIG. 6 shows a modification of the first embodiment. In the modified example, since the annular sliding portion 56 is formed integrally with the mover 21 on the outer periphery of the end of the mover 21 on the fixed iron core 55 side, and the mover 21 side of the fixed iron core 55 is formed flat, The child 21 can reciprocate using the sliding portion 56 as a guide. The outer peripheral wall of the sliding portion 56 is a resin bobbin 1.
Since it slides on the inner wall of No. 3, it is desirable to apply this modification to a solenoid valve in which the excitation current supplied to the coil 13 is less frequently turned on and off, that is, the number of sliding times between the sliding portion 56 and the bobbin 13 is less.

In the modification shown in FIG. 6, the guide member 22 of the first embodiment is unnecessary, so that the solenoid valve can be constructed at a low cost. (Second Embodiment) A second embodiment of the present invention is shown in FIG. A cylindrical hole 10 for accommodating the poppet valve 20 and the mover 21 and allowing them to slide smoothly is provided inside the iron body 60 in the axial direction. The cylindrical hole 10 is opposite to the mover 21. An oil passage 60a is formed on the side, and an oil passage 61 is formed on the oil upstream side of the oil passage 60a. Oil is supplied to the oil passage 61 from an oil supply source (not shown). Oil passage 60a and oil passage 61
An oil passage 62a, which can communicate with the oil passage 60a and the oil passage 61, is formed at a boundary portion between and piercing a side wall of the body 60 in the radial direction. The oil passage 63 is formed by radially penetrating the side wall of the body 60 so as to communicate with the oil passage 60a. The outer peripheral wall of the body 60 in which the oil passage 63 is formed is cut out in an annular shape.

The guide member 22 is made of a non-magnetic material and is sandwiched between the magnetic circuit portion 60b and the annular portion 15c. The movable part including the poppet valve 20 and the mover 21 slides at a position different from the fixed part including the body 60 and the guide member 22 in the axial direction. The poppet valve 20 is biased toward the annular seat member 64 side fixed to the inner wall of the body 60 by the biasing force of the compression coil spring 16, but does not sit on the seat member 64. The ball valve 51 is accommodated between a valve seat 60c formed on the body 60 and a valve seat 64a formed on the seat member 64 such that the ball valve 51 can move in a predetermined axial direction.

Next, the operation of the solenoid valve 70 will be described. (1) When the coil 14 is de-energized, the moving element 21, the poppet valve 20 and the ball valve 51 are urged downward in FIG. 7 by the urging force of the compression coil spring 16 and are supplied from the oil supply source to the oil passage 61. Ball valve 51 against hydraulic pressure
Sits on the valve seat 60c. As a result, the oil passage 61
The communication between the oil passage 62 and the oil passage 62 is cut off, and the oil passage 60a
And the oil passage 62 are communicated with each other, the oil passage 62 from the oil passage 62 that supplies oil to the hydraulic control target
Oil is discharged to the drain through the oil passage 63 and the oil passage 11a.

(2) When the coil 14 is energized, the magnetic force generated in the coil 14 causes the mover 21 to move to the fixed core 1.
The ball valve 51 is sucked to the 5 side, and is seated on the valve seat 64a by the hydraulic pressure in the oil passage 61. Then, the communication between the oil passage 60a and the oil passage 62 is cut off, the oil passage 61 and the oil passage 62 communicate with each other, and the oil is supplied to the hydraulic control target.

Unlike the first embodiment, the second embodiment is a normally closed solenoid valve in which the oil passage 61 on the oil supply side is closed when the coil 14 is de-energized. Similarly to the example, the side gap 30 between the magnetic circuit portion 60b and the mover 21 made of a magnetic material, which reduces the sliding frictional force between the movable part and the fixed part, can be reduced, and the outer diameter of the mover 21 can be increased. This has the effect of increasing the suction force acting on the mover 21.

In the embodiments of the present invention described above, the solenoid valve of the present invention is applied to the three-way valve having three-way fluid inlet / outlet ports. However, in the present invention, the present invention is applied to a two-way valve having two-way fluid inlet / outlet ports. It is possible to apply the solenoid valve. Further, in the present embodiment, the solenoid valve of the present invention is used to control the flow path of oil, but in the present invention, the solenoid valve of the present invention is used to control the flow path of liquid such as water, light oil, gasoline, and gas such as air. It is also possible to use.

[Brief description of drawings]

FIG. 1 is a sectional view showing a solenoid valve according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of the first embodiment.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a perspective view showing a support member of the first embodiment.

FIG. 5 is a characteristic diagram showing a relationship between a diameter of a mover and a suction force.

FIG. 6 is a sectional view showing a modification of the first embodiment.

FIG. 7 is a sectional view showing a solenoid valve according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solenoid valve 10 Cylindrical hole 10a Space part 11 Case 11a Oil passage 12 Body 12a Magnetic circuit part 12b Oil passage 13 Bobbin 14 Coil 15 Fixed iron core 16 Compression coil spring (biasing means) 20 Poppet valve (valve body) 20c Flange part ( Second sliding part) 21 Mover 22 Guide member (first sliding part) 41 Oil passage (accommodation hole) 42 Oil passage 43 Oil passage (fluid passage hole) 50 Supporting member 50b Slit 51 Ball valve 55 Fixed iron core 56 Sliding part 100 Mating part (mounting part)

Claims (4)

[Claims] 1. A body having a cylindrical hole inside, a bobbin provided on the body and wound with a coil, a case arranged on the outer periphery of the bobbin, and a case provided adjacent to one end of the bobbin. A fixed iron core, a mover housed in the cylindrical hole so as to be able to reciprocate, and magnetically attracted to the fixed iron core side by energizing the coil, and fixed to an end of the mover opposite to the fixed iron core. A solenoid valve having a movable part having a valve body made of a non-magnetic material capable of reciprocating in the cylindrical hole, and an urging means for urging the movable part opposite to the fixed iron core. The movable part is slidable at one end on the fixed core side of the mover and on the first sliding part of the inner peripheral wall of the bobbin, and at the other end slidable on the inner peripheral wall of the cylindrical hole provided in the valve body. The second sliding portion allows reciprocating movement on the inner peripheral wall of the cylindrical hole of the body. Solenoid valve characterized by being supported by Noh. 2. The outer circumference of the mover is smaller than the outer diameter of the second sliding portion so as to minimize the magnetic gap formed by the outer circumference wall of the mover and the inner circumference wall of the cylindrical hole. The outer diameter of the wall is made slightly smaller.
The solenoid valve described. 3. A solenoid valve of a three-way valve for controlling opening / closing of three fluid passages by the valve element and a ball valve, the cylindrical valve having a housing hole capable of housing the ball valve in an axial direction. 3. The solenoid valve according to claim 1, further comprising a formed resin support member, wherein the solenoid valve is insertable into the body by a slit formed in an axial direction of a side wall of the support member. 4. When assembled to a mounting part, the body of the body housed in the mounting part serves as a fluid discharging means from the cylindrical hole of the part of the body housed in the mounting part to the outside of the mounting part. A fluid passage hole is formed penetrating the side wall in the radial direction to communicate with the cylindrical hole, and the periphery of the outer wall of the body in which the fluid passage hole is formed is cut out to the outside of the mounting portion to form the fluid passage hole. The solenoid valve according to claim 1, 2 or 3, wherein an annular space portion communicating with the solenoid valve is formed.