JPH0534015Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an electromagnetic relief valve that suppresses vibrations of a seat member.

<Prior art> An electromagnetic relief valve is used, a spool and a seat member are slidably inserted into a valve hole, and the spool is sucked by a solenoid overcoming a spring to open and close a relief passage using the seat member. There is something I did.

As shown in FIG.
An annular groove 2 is formed in the annular groove 2, and an O-ring 3 is inserted into the annular groove 2.
and Teflon ring 4 is fitted.

<Problems to be Solved by the Invention> In the electromagnetic relief valve described above, when the pressure in the relief passage 5 fluctuates greatly, the seat member 1 may vibrate in an attempt to keep the pressure in the relief passage 5 constant. This vibration includes transverse vibration and longitudinal vibration, and the damping of the transverse vibration occurs when the Teflon ring 4 moves when the sheet member 1 is moved in the radial direction by a gap of 6.
This is done by elastically deforming the O-ring 3 via the . However, due to longitudinal vibration, since there is a gap 7 in the axial direction between the Teflon ring 4 and the seat member 1, the frictional force between the Teflon ring 4 and the valve hole 8 is
It cannot be transmitted and attenuated. Therefore, there was a problem in that relief pressure fluctuations occurred due to the longitudinal vibration of the sheet member 1, and that these relief pressure fluctuations continued for a long time.

<Means for solving the problem> The present invention was made to solve the above-mentioned problem, and includes forming a fitting hole at one end of the spool,
Forming a small diameter part in the seat member to fit into the fitting hole of the spool, forming a large diameter part continuous to the small diameter part, and fitting an O-ring into the small diameter part on the large diameter part side;
Furthermore, a Teflon ring is fitted onto the outer periphery of the O-ring, which is sandwiched between the end surface of the spool and the large diameter portion of the seat member, and which slides into contact with the valve hole of the valve body.

<Function> With the above-described configuration, when the pressure of the fluid acting on the seat member through the relief passage increases, the seat member moves in a direction away from the valve seat surface of the valve seat member, and the pressure in the relief passage is transferred to the valve hole. to the low pressure passage. When the pressure in the relief passage suddenly increases, the spool and the seat member move rapidly in order to release this pressure to the low pressure passage through the valve hole, causing vibrations in the spool and the seat member. Lateral vibrations of the seat member are damped by moving the seat member in the radial direction and elastically deforming the O-ring via the Teflon ring. The longitudinal vibration of the seat member is damped by the frictional force between the valve hole and the Teflon ring during the transverse vibration.

<Examples> Examples of the present invention will be described below based on the drawings. In FIG. 1, a valve body 11 is fixed to a housing 10, and a through hole 12 is formed in the valve body 11. A sleeve 13 made of a non-magnetic material is fitted and fixed to the upper end of the valve body 11, and a yoke 14 is further fitted to the inner periphery of the upper end of the sleeve 13.
are fitted and fixed. A non-magnetic ring 15 is interposed between the valve body 11 and the sleeve 13 on the inner periphery of the sleeve 13. A bobbin 16 is arranged around the outer periphery of the sleeve 13, and a solenoid 17 is provided on the bobbin 16. The solenoid 17 is surrounded by a cover 18, and the lower end of the cover 18 is joined to the valve body 11. An adjustment screw 20 is screwed into the yoke 14, and a nut 21 is screwed into the adjustment screw 20 via the cover 18, thereby fixing the cover 18 to the valve body 11.

A guide member 22 is fitted and fixed to the lower end of the valve body 11, and a valve seat member 23 is fitted to the guide member 22.
are fitted and fixed. A spool 25 and a seat member 26 are slidably inserted into the valve hole 24 formed by the inner peripheral surface of the guide member 22 and the through hole 12 of the valve body 11, and the spool 25 is inserted between the spool 25 and the adjustment screw 20. A spring 27 is inserted to press downward. A fitting hole 30 is formed at the lower end of the spool 25, and a small diameter portion 31 of the sheet member 26 is fitted into the fitting hole 30. As shown in FIG. 2, an extremely small gap A is formed between the fitting hole 30 and the small diameter portion 31 so that the sheet member 26 can move in the radial direction with respect to the spool 25. A large diameter portion 32 is formed in the sheet member 26 continuously from a small diameter portion 31, and a holding hole 33 is formed at the lower end. A ball 34 is fixed in the holding hole 33. An O-ring 35 is fitted into the small-diameter portion 31 of the sheet member 26 on the large-diameter portion 32 side, and a Teflon ring 36 is fitted into the outer periphery of the O-ring 35. The upper and lower surfaces of the Teflon ring 36 are in contact with the end surface of the spool 25 and the large diameter portion 32 of the seat member 26, respectively, and the outer periphery of the Teflon ring 36 is in sliding contact with the valve hole 24.

A seat surface 40 on which the ball 34 comes into contact is formed on the seat member 26 side of the valve seat member 23, and a relief passage 41 communicating with this seat surface 40 is formed. One side of the relief passage 41 communicates with a high pressure passage 42 formed in the housing 10.
1 is in communication with a low pressure passage 43 formed in the housing 10 via the valve hole 24. High pressure passage 4
2 and the low pressure passage 43 are respectively connected to a pump and a tank (not shown).

Next, the operation will be explained based on the above-described configuration. When a current is applied to the solenoid 17, magnetic lines of force are generated that pass through the cover 18, yoke 14, spool 25, and valve body 11, and attract the spool 25 toward the yoke 14. A force F obtained by subtracting the suction force by the solenoid 17 from the force of the spring 27 acts on the spool 25 as a whole, and the pressure in the relief passage 41 is determined by this force F. When the pressure acting on the sheet member 26 through the relief passage 41 exceeds the force F, the spool 2
5 and the seat member 26 are displaced upward, the opening degree of the passage where the relief passage 41 communicates with the valve hole 24 becomes larger, and the pressure inside the relief passage 41 is lowered. Conversely, when the pressure acting on the sheet member 26 through the relief passage 41 decreases, the force F causes the spool 2 to
5. The seat member 26 is displaced downward to close the passage through which the relief passage 41 communicates with the valve hole 24.

When the pressure inside the relief passage 41 increases rapidly, the force exerted by the spring 27 and the solenoid 17
The balance between the force caused by the oil pressure and the force caused by the oil pressure is lost, and the spool 25 and the seat member 26 begin to vibrate. This vibration is longitudinal vibration accompanied by transverse vibration, and the transverse vibration is attenuated by the sheet member 26 moving in the radial direction and the O-ring 35 being elastically deformed via the Teflon ring 36. For longitudinal vibration, O-ring 3
5 is elastically deformed and the Teflon ring 36 and valve hole 24
It is damped by the frictional force acting between them. When the sheet member 26 vibrates, the relief passage 41
Since the degree of opening of the passage communicating with the valve hole 24 changes, the pressure inside the relief passage 41 fluctuates. However, since the vibration of the sheet member 26 subsides in a short period of time, the pressure fluctuation within the relief passage 41 subsides in a short period of time.

In the embodiment described above, even if the Teflon ring expands or contracts due to heat, the spool 25 and the seat member 26 are pressed by the pressure of the spring 27 and the oil, so the Teflon ring 36 and the spool 25
Alternatively, no gap is created between the sheet members 26.

In the above embodiment, the seat member 26 and the ball 34 are separate bodies, but the ball may be integrally formed with the seat member.

<Effects of the invention> As described above, in the present invention, when the pressure of the fluid acting on the seat member through the relief passage becomes high, the seat member separates from the valve seat surface of the valve seat member, and the pressure is applied to the valve hole. The pressure inside the relief passage is controlled so that it does not exceed a predetermined pressure. When the pressure in the relief passage suddenly increases, the spool and seat member move rapidly, causing the spool and seat member to vibrate.In this invention, an O-ring is fitted into the small diameter part, and a Teflon ring is placed around the outer circumference of the O-ring. Since the O-ring is fitted so as to be sandwiched between the end face and the large diameter portion of the sheet member, the O-ring is elastically deformed via the sheet member and the Teflon ring, and lateral vibration can be damped. Moreover, the frictional force between the valve hole and the Teflon ring can be transmitted to the seat member without play, and the longitudinal vibration of the seat member can be damped. As a result, relief pressure fluctuations can be reduced in a short time.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the electromagnetic relief valve according to the present invention, FIG. 2 is an enlarged cross-sectional view of the main part, and FIG. 3 is an enlarged cross-sectional view of the conventional main part. 11... Valve body, 17... Solenoid, 2
3... Valve seat member, 24... Valve hole, 25... Spool, 26... Seat member, 27... Spring,
30... Fitting hole, 31... Small diameter part, 32... Large diameter part, 35... O ring, 36... Teflon ring,
40... Valve seat surface, 41... Relief passage.

Claims (1)

[Scope of utility model registration request] A spool is slidably inserted into the valve hole of the valve body, and a seat member is movably inserted,
A valve seat member that forms a valve seat surface that this seat member contacts and a relief passage that communicates with this valve seat surface is provided at one end of the valve body, and a solenoid that suctions the spool by overcoming a spring is provided at the other end of the valve body. and when the pressure of the fluid in the relief passage acting on the seat member exceeds a predetermined pressure due to the biasing force of the spring and the suction force of the solenoid, the fluid in the relief passage is transferred to the low pressure passage through the valve hole. In the electromagnetic relief valve, a fitting hole is formed at one end of the spool, a small diameter part is formed in the seat member to fit into the fitting hole of the spool, and a large diameter part is formed continuously to the small diameter part. Then, fit an O-ring into the small-diameter part of the large-diameter side, and then fit a Teflon ring to the outer periphery of the O-ring, which is sandwiched between the end face of the spool and the large-diameter part of the seat member and slides into the valve hole of the valve body. An electromagnetic relief valve characterized by: