JPH0540680U - solenoid valve - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the operating noise caused by the impact of the movable valve element generated in the solenoid valve. [Structure] Generally, in a solenoid valve, a spring having a single spring constant is used. However, by changing this spring to a spring having two or more spring constants, immediately before the movable valve body comes into contact with the fixed iron core. The spring constant of the spring increases, and the spring load suddenly increases. The change in this load absorbs the contact energy. On the contrary, when the movable valve body comes into contact with the valve seat, the load of the spring is weakened, and the contact energy is weakened. Therefore, the operating noise at the time of operating the solenoid valve can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic valve that opens and closes a valve body by electromagnetic force.

[0002]

[Prior Art]

 FIG. 3 is a sectional view showing a conventional solenoid valve. In FIG. 3, reference numeral 1 is a resin bobbin around which the electromagnetic coil 2 is wound, and 3 is an external connection terminal embedded in its mounting hole. Reference numeral 4 denotes a synthetic resin exterior member provided on the outer circumference of the electromagnetic coil 2, which has a seal groove 4a at one end of the joint surface with the bobbin 1 and the other end at the same level as the bobbin surface on the internal passage 5d side described later. It has a cylindrical joint surface. Reference numeral 5 denotes a valve seat, which is molded by incorporating a plate 6 that forms a magnetic circuit, and has an internal passage 5d, nipples 5a and 5b, and a valve seat 5c. Reference numeral 7 denotes a movable valve body that is provided slidably in the internal passage 5d of the valve seat 5 in the axial direction and switches the internal fluid passage. The movable valve body 7 is a non-magnetic seal with the iron core 7a. It consists of surfaces 7b and 7c. Reference numeral 8 denotes a yoke, one end of which is integrally joined to the fixed iron core 9 and the other end of which is fixed to the step portion of the valve sheet 5 by caulking, and which contacts the outer peripheral surface of the plate 6 to form a magnetic circuit. .. Reference numeral 10 denotes a seal material arranged in the seal groove 4a, which is pressed by the yoke 8 to ensure the airtightness of the bobbin 1 and the exterior member 4. The sealing material 10 arranged in the sealing groove at the other end in the same manner is pressed by the plate 6 to ensure the airtightness of the bobbin 1 and the exterior member 4. Reference numeral 11 denotes a spring having a single spring constant, which is disposed between the cylindrical hole 9a at the tip of the fixed iron core and the cylindrical hole 7d provided at the seal 7c of the movable valve body 7. Thus, when the electromagnetic coil 2 is not energized, the movable valve body 7 acts to separate from the fixed iron core 9.

Next, the operation will be described. The solenoid valve configured as described above responds to an operation command signal from a control device using a battery or the like as a power source for controlling exhaust gas of a vehicle or engine, and switches the control fluid. That is, when a signal current flows from the terminal 3, the electromagnetic coil 2 is excited and a magnetic circuit including the fixed iron core 9, the yoke 8, the plate 6, and the movable valve body 7 is formed. When the magnetic attraction force rises above the valve holding force, the movable valve body 7 slides and displaces to the right in FIG. 3 against the bias of the spring 11, and the valve seat 5c moves toward the movable valve body 7. It is separated from the sealing surface 7b, and the nipples 5a and 5b communicate with each other. On the contrary, when the signal current to the electromagnetic coil 2 is cut off, the electromagnetic coil 2 is de-excited and the movable valve body 7 moves leftward by the urging force of the spring 11 to move the valve of the fixed iron core 9 as shown in the figure. The seat 9b and the sealing surface 7c of the movable valve body 7 are separated from each other, and the valve seat 5c and the sealing surface 7b of the movable valve body 7 are brought into contact with each other to interrupt the flow path between the nipples 5a and 5b.

[0004]

[Problems to be solved by the device]

 The conventional solenoid valve is constructed as described above. The electromagnetic coil 2 is excited, and the movable valve body 7 slides and displaces against the bias of the spring 11. Since the electromagnetic force acting on 7 changes exponentially with respect to the displacement of the movable valve body, a considerably high contact noise is generated when the movable valve body tip and the fixed iron core tip come into contact with each other via the sealing surface. There was a problem.

The present invention has been made to solve the above problems, and an object thereof is to reduce the contact noise due to the sliding displacement of the movable valve body.

[0006]

[Means for Solving the Problems]

 The electromagnetic valve according to the present invention has a structure in which the elastic body for holding and returning the movable valve body has a spring constant of two stages or more.

[0007]

[Action]

 The elastic body in this invention, when in a non-excited state, separates the movable valve body from the fixed iron core by its urging force, and further keeps the movable valve body airtight on the valve seat surface. On the other hand, when the electromagnetic coil is excited and the movable valve body slides and moves against the biasing force of the elastic body, the displacement amount increases and the spring of the elastic body increases before the movable valve body tip and the fixed core tip contact. The constant changes from the first spring constant to the second spring constant, and the spring constant increases, which causes the elastic body's urging force to increase sharply, weakening the impact of contact, and reducing contact noise. I do.

[0008]

【Example】

 Example 1. FIG. 1 shows an enlarged sectional view a of a main part according to one embodiment of the present invention and a characteristic diagram b of the spring of the present invention and the conventional example. That is, in FIG. 1, 12 is a spring having a two-stage spring constant, which is fitted between the recess 7d of the movable valve body 7 and the recess 9a of the fixed iron core 9. The other configurations are the same as the conventional ones and will not be described.

Next, the operation will be described. In the solenoid valve configured as described above, when the signal current flows from the terminal 3, the solenoid coil 2 is excited and a magnetic circuit including the fixed iron core 9, the yoke 8, the plate 6, and the movable valve body 7 is formed. When the magnetic attraction force overcomes the urging force of the spring 12, the movable valve body 7 slides and displaces to the right in FIG. 1, but at this time, the movable valve body 7 is fitted between the movable valve body 7 and the fixed iron core 9. The spring 12 is axially compressed, and its urging force increases. As shown in Fig. 1 (b), the urging force at the time of compression is set so that it gradually changes up to a certain amount of sliding displacement and changes abruptly above that amount. Immediately before the iron core 9 and the movable valve body 7 come into contact with each other, the urging force sharply increases, and the impact due to the contact is weakened. By the above operation, the seal surface 7b of the movable valve body 7 is opened by the valve seat 5c, and the nipples 5a and 5b are in communication with each other. Conversely, when the signal current to the electromagnetic coil 2 is cut off, the electromagnetic coil 2 is de-excited and the movable valve body 7 moves leftward due to the repulsive force of the spring 12, as shown in FIG. 1 (b). Then, the valve seat 5c and the sealing surface 7b of the movable valve body 7 are brought into contact with each other to shut off the flow path between the nipples 5a and 5b. At this time, the spring 12 extends in the axial direction, but when the valve seat 5c and the sealing surface 7b of the movable valve body 7 come into contact with each other, the repulsive force of the spring is weak and the impact due to the contact is weakened.

Example 2. FIG. 2 shows another embodiment of the present invention, which is an example using two springs. The first spring 13 has a cylindrical hole 9a at the tip of the fixed iron core 9 as in the above. The second spring 14 is provided between the cylindrical hole 7d provided in the seal portion 7c of the movable valve body 7, and the second spring 14 is provided between the outer peripheral portion of the fixed iron core 9 and the outer peripheral portion of the movable valve body 7. The spring 14 is arranged between the fixed core 9 and the movable valve body 7 immediately before the fixed core 9 and the movable valve body 7 contact each other.

[0011]

[Effect of the device]

 As described above, according to the present invention, the movable valve body and the fixed iron core, the movable valve body seal surface and the valve seat are used by using the elastic body having two or more spring constants for holding and returning the movable valve body. It is possible to reduce the contact noise with the.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view a of a main part of a solenoid valve according to an embodiment of the present invention, and a comparative characteristic diagram (b) of a spring used in the present invention and a conventional spring.

FIG. 2 is an enlarged cross-sectional view of a main part showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional solenoid valve.

[Explanation of symbols]

 1 bobbin 2 electromagnetic coil 3 external connection terminal 7 movable valve body 9 fixed iron core 12 two-stage spring constant spring 13, 14 spring

Claims (3)

[Scope of utility model registration request] 1. A bobbin having an electromagnetic coil wound around the outer periphery thereof, a valve seat joined to the bobbin and having a nipple forming a flow path with an internal passage and a valve seat, and a fixing provided in the bobbin. An iron core and a movable valve body that is slidably provided in the internal passage of the valve seat so as to face the fixed iron core, and the movable valve body is held between the movable valve body and the fixed iron core. And an elastic member that has a biasing force for returning and has a first spring constant up to a specific operation region and a second spring constant after that. 2. A bobbin having an electromagnetic coil wound around the outer periphery thereof, a valve seat joined to the bobbin, having a nipple forming a flow path with an internal passage and a valve seat, and a fixing member provided in the bobbin. An iron core and a movable valve body that is slidably provided in the internal passage of the valve seat so as to face the fixed iron core, wherein the movable valve body is provided between the concave portion and the fixed iron core. , A solenoid valve having an elastic member having a spring constant of two stages or more. 3. A bobbin having an electromagnetic coil wound around the outer periphery thereof, a valve seat joined to the bobbin, having a nipple forming a flow path with an internal passage and a valve seat, and a fixing provided in the bobbin. An iron core and a movable valve body that is slidably provided in the internal passage of the valve seat so as to face the fixed iron core, wherein the movable valve body is provided between the concave portion and the fixed iron core. The first spring is fitted and the second spring is fitted and inserted between the outer peripheral portion of the recess, and the second spring is connected to the outer peripheral portion of the movable valve body immediately before the fixed iron core and the movable valve body come into contact with each other. A solenoid valve characterized by being set so as to abut.