JP2022085243A - Normal open type electromagnetic valve - Google Patents

Abstract

To provide a normal open type electromagnetic valve which can attain damper effect to suppress self-excited vibration therein and can inhibit deterioration of responsiveness.SOLUTION: In a normal open type electromagnetic valve 100, a plate 180 provided with an orifice 182 is disposed at the spool 130 side of a stopper 170 and a damper chamber 190 is formed at the spool side of the plate. An oil discharge passage 166 communicating with the outside is formed at the electromagnetic part side of the plate. The damper chamber and the oil discharge passage communicate through the orifice. Further, a center hole 184 is formed at a center of the plate, and a small diameter shaft 140 inserted into the center hole is provided at the electromagnetic part side of the spool. At a position corresponding to the plate, an outer diameter of the small diameter shaft has a shape along an inner diameter of the center hole when the spool is in one of both end ranges of the stroke and a rod groove 142 for allowing an oil to pass through a gap formed between the rod groove and the center hole is formed at a pressure regulation range of the stroke.SELECTED DRAWING: Figure 1

Description

The present invention relates to a normally open solenoid valve capable of suppressing self-excited vibration.

Of the solenoid valves, the one that is normally open and closed during driving is called the normal open type, and the one that is normally closed and opened during driving is called the normally closed type. Patent Document 1 is an example of a normally open type, and Patent Document 2 is an example of a normally closed type.

These solenoid valves may be provided with a feedback port. As shown in Patent Document 1, in the normally open type, a feedback port is arranged on the electromagnetic part side, a feedback force is given in a direction against the return spring, and the spring force balances the feedback force and the plunger thrust of the electromagnetic part. It is configured as follows. As shown in Patent Document 2, in the normally closed type, a feedback port is arranged on the return spring side so that the spring force and the feedback force are balanced with the plunger thrust of the electromagnetic part.

In a solenoid valve, the hydraulic pressure applied to the input port or output port may rise sharply. In a normally open solenoid valve, when the hydraulic pressure becomes high, the spool may move due to the feedback force and the valve may close even if the solenoid part is not operating. When the valve closes, the output pressure drops, so the feedback force also drops, and the spring force returns the spool and opens the valve. By repeating this, self-excited vibration of the valve is generated.

Patent Document 1 (normally open type) describes that a stroke range regulating means for restricting the axial movement of the spool toward the return spring side at a position where the output port and the discharge are communicated with each other and the input port is closed is provided. Has been done. However, there is no mechanism to suppress hydraulic vibration when it occurs, and vibration cannot be suppressed.

Patent Document 2 (normally closed type) discloses that a throttle portion (orifice) is provided in a drain port of a spring chamber to suppress vibration of a spool valve by a damper effect. It is stated that this will ensure oil vibration resistance against external factors that make the inflow and outflow unstable.

Japanese Patent No. 5747744 Japanese Patent No. 4692413

In the configuration of Patent Document 2 (normally closed type), since the feedback chamber next to the spring chamber (almost normal pressure (atmospheric pressure)) has a high pressure, there is a pressure difference between these chambers, and oil is released. Since oil leaks between the sleeve and spool clearances and accumulates in the spring chamber, the damper effect of the orifice can be obtained. However, in the case of the normally open type as in Patent Document 1, since the drain chamber is arranged next to the spring chamber, there is almost no pressure difference between these chambers. Then, since the oil does not leak to the spring chamber, there is a problem that the damper effect cannot be obtained.

Therefore, it is an object of the present invention to provide a normally open solenoid valve capable of obtaining a damper effect and suppressing self-excited vibration even in a normally open solenoid valve and further suppressing deterioration of responsiveness. It is supposed to be.

The inventors first got the idea that self-excited vibration can be suppressed by arranging a plate provided with an orifice on the stopper side of the spool to form a damper chamber and an oil discharge path in order to obtain a damper effect. However, if the damper effect is always functioning, resistance will be generated against changes in the volume of the damper chamber even when the spool moves as normal operation, so the problem is that the responsiveness of the solenoid valve will decrease. There is. Therefore, the inventors further studied and came to complete the present invention.

In order to solve the above problems, a typical configuration of the present invention is a sleeve having at least an input port, an output port and a drain port, a spool slidably supported in the sleeve, and a spool toward one side. In a normally open solenoid valve equipped with a urging spring, an electromagnetic part that drives the spool toward the other side, and a stopper arranged on the spool side of the electromagnetic part, a plate provided with an orifice on the spool side of the stopper is provided. Arranged, a damper chamber is formed on the spool side of the plate, an oil discharge path is formed on the electromagnetic part side of the plate to communicate with the outside, and the damper chamber and the oil discharge path are communicated by an orifice, and further, the plate is further connected. A central hole is formed in the center of the spool, and a small diameter shaft inserted into the center hole is provided on the solenoid side of the spool. The outer diameter at the time of is in the shape along the inner diameter of the central hole, and is characterized in that a groove for allowing oil to pass through a gap with the central hole is formed in the pressure adjusting region of the stroke.

According to the above configuration, since the normal pressure damper chamber is adjacent to the high pressure feedback chamber, the oil leaked from the feedback chamber collects in the damper chamber. Therefore, the damper effect due to the orifice can be obtained, and the self-excited vibration of the spool can be suppressed.

Further, in the pressure adjustment region of the spool stroke, oil passes through the gap between the groove formed on the small diameter shaft and the central hole of the plate in addition to the orifice, so that the flow path area is expanded. Therefore, the damper effect can be reduced in the pressure adjustment region of the stroke, and the movement of the spool is not hindered, so that deterioration of responsiveness can be suppressed.

According to the present invention, it is possible to provide a normally open solenoid valve capable of obtaining a damper effect and suppressing self-excited vibration even in a normally open solenoid valve and further suppressing deterioration of responsiveness. can.

It is a figure explaining the normal open type solenoid valve which concerns on embodiment. It is a figure explaining the main part. It is a figure explaining the structure of a rod groove. It is a figure explaining the action of a rod groove.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and the drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate description, and elements not directly related to the present invention are illustrated or described. Is omitted.

FIG. 1 is a diagram illustrating a normally open solenoid valve (hereinafter, simply referred to as “solenoid valve 100”) according to the present embodiment. FIG. 1 shows a state in which the valve is open (non-excited state).

The solenoid valve 100 shown in FIG. 1 is a three-way valve, which is a proportional valve capable of adjusting the flow rate of oil according to the opening degree of the valve. The solenoid valve 100 includes a substantially cylindrical sleeve 110 and a spool 130 slidably supported inside the sleeve 110.

A spring 150 is built in one end of the sleeve 110 to urge the spool 130 toward the solenoid portion 160. The solenoid portion 160 attached to the other end of the sleeve 110 moves the plunger 164 by exciting the coil 162, and moves the spool 130 toward the spring 150 via the pusher 168. A stopper 170 is provided on the spool 130 side of the solenoid portion 160, and the sleeve 110 is abutted against the stopper 170.

The sleeve 110 is provided with an input port 112 to which hydraulic oil is supplied and an output port 114 to output hydraulic oil when the solenoid valve 100 is open. The circumference of the output port 114 has a wide inner diameter, which is called a pressure control chamber 114a. The output port 114 branches and some hydraulic fluid is returned to the feedback port 116. The circumference of the feedback port 116 has a wide inner diameter, which is called a feedback chamber 116a. The circumference of the drain port 118 has a wide inner diameter, which is called the drain chamber 118a. The inner diameter of the spring 150 is also wide, and this is called the spring chamber 150a. The spring chamber 150a communicates with the outside by a discharge port 122 provided in the adjuster 120 that adjusts the load of the spring 150.

The spool 130 is formed with a plurality of steps having different diameters for opening and closing each port of the sleeve 110. The large diameter part is called a land, which is basically a place where oil does not flow (a place where the port is closed), but if there is a pressure difference between the chambers, hydraulic oil leaks from the clearance (gap). The first land 132 opens and closes the drain port 118. The second land 134 opens and closes the input port 112. The third land 136 divides the feedback chamber 116a and the damper chamber 190, which will be described later. Further, on the electromagnetic portion 160 side of the spool 130, a small diameter shaft 140 pushed by the pusher 168 of the electromagnetic portion 160 is provided.

When the solenoid portion 160 is not excited, the spool 130 is pushed by the spring 150 and is positioned closer to the solenoid portion 160 side as shown in FIG. At this time, the input port 112 and the output port 114 communicate with each other by the small diameter portion 138 between the first land 132 and the second land 134, and the hydraulic oil is output. In this state, the solenoid valve 100 is said to be open (normally open).

When the solenoid portion 160 is excited, the spool 130 is pushed by the pusher 168 of the solenoid portion 160 and moves to the left in the drawing. At this time, the input port 112 is closed by the second land 134, and the output port 114 and the drain port 118 communicate with each other by the small diameter portion 138. Since the pressure of the output port 114 is the same as that of the drain port 118 and becomes normal pressure, the pressure is not transmitted to the output side. In this state, the solenoid valve 100 is said to be closed.

Here, the pressure applied to the feedback port 116 is the same as that of the output port 114. When the solenoid valve 100 is closed, the feedback port 116 also becomes normal pressure, but when the solenoid valve 100 is open, the pressure (high pressure) of the input port 112 is also applied to the feedback port 116. Since the diameter of the second land 134 is larger than that of the third land 136 and the pressure receiving area changes depending on the difference in diameter, the spool 130 is urged toward the spring 150 by the internal pressure of the feedback chamber 116a. This encouraging force is called feedback force. As a result, the feedback force and the plunger thrust of the electromagnetic part are configured to be balanced with the spring force.

However, if the hydraulic pressure applied to the input port 112 or the output port 114 suddenly rises, the spool 130 moves due to the feedback force even if the solenoid unit 160 is not operating, and the solenoid valve 100 is closed. In some cases. When the solenoid valve 100 is closed, the pressure of the output port 114 decreases, so that the feedback force also decreases, the spool 130 returns due to the spring force, and the valve opens. By repeating this, self-excited vibration of the valve is generated.

Therefore, in the present embodiment, a damper mechanism is configured on the electromagnetic portion 160 side adjacent to the feedback chamber 116a.

FIG. 2 is a diagram illustrating a main part. As shown in FIGS. 1 and 2A, a plate 180 provided with an orifice 182 (see FIG. 2) is arranged on the spool 130 side of the stopper 170. As shown in FIGS. 2A and 2B, a central hole 184 through which the small diameter shaft 140 of the spool 130 is inserted is provided in the center of the plate 180. Then, on the spool 130 side of the plate 180, a damper chamber 190 surrounded by the inner surface of the sleeve 110, the outer surface of the small diameter shaft 140, and the plate 180 is formed.

On the other hand, as shown in FIG. 1, an oil discharge passage 166 communicating with the outside is formed on the electromagnetic portion 160 side of the plate 180. The damper chamber 190 and the oil discharge passage 166 communicate with each other by an orifice 182.

Specifically, as shown in FIG. 2 (c), the stopper 170 includes a cylindrical boss 172 through which the small diameter shaft 140 of the spool 130 is inserted and which supports the plate 180. A radial groove 174 is formed in the cylindrical boss 172 at a position corresponding to the orifice 182. The outer circumference of the cylindrical boss 172 is an oil discharge path 166, which communicates with the radial groove 174. The oil discharge passage 166 was attached to the outer peripheral surface of the cylindrical boss 172, the front surface 176 of the stopper (the surface of the stopper 170 on the sleeve 110 side), the caulking portion 160a of the casing of the electromagnetic portion 160, and the sleeve 110. It is a space surrounded by a flange 124 for caulking. The flange 124 is provided with a notch, and this notch serves as a discharge port 124a.

According to the above configuration, since the normal pressure damper chamber 190 is adjacent to the high pressure feedback chamber 116a, the oil leaking from the feedback chamber 116a collects in the damper chamber 190. Therefore, the damper effect due to the orifice 182 can be obtained, and the high-speed movement of the spool 130 can be alleviated, so that the self-excited vibration of the spool 130 can be suppressed.

However, if the damper effect due to the orifice 182 is always functioning, resistance is generated against a change in the volume of the damper chamber 190 even when the spool 130 moves as a normal operation, so that the responsiveness as a solenoid valve is improved. It will drop. Therefore, a groove (hereinafter referred to as "rod groove 142") is provided on the small diameter shaft 140.

FIG. 3 is a diagram illustrating the configuration of the rod groove 142. FIG. 3A shows the start point region of the spool stroke, FIG. 3B shows the pressure adjustment region of the stroke, and FIG. 3C shows the end point region of the stroke. As shown in FIGS. 3A and 3C, the outer diameter of the small diameter shaft 140 at the position corresponding to the plate 180, when it is in the start point region and the end point region, that is, both end regions, is along the inner diameter of the central hole 184. The shape. "Shape along the inner diameter" means a negative tolerance, which means that it is slidable but has a clearance that allows almost no oil to pass through. At this time, since the oil can flow only from the orifice 182, the damper function acts against the vibration.

Then, as shown in FIG. 3B, when the spool 130 is in the pressure adjustment region (central region) of the stroke, the rod groove 142 overlaps with the position of the plate 180. Then, in addition to the opening area of the orifice 182, oil also flows from the gap 186. The rod groove 142 is formed so that the opening area of the gap 186 (which becomes an annular gap) between the rod groove 142 and the central hole 184 of the plate 180 is significantly larger than the opening area of the orifice 182. It is preferable to set the width and depth.

FIG. 4 is a diagram illustrating the operation of the rod groove 142. FIG. 4A is a diagram showing the pressure of the output port 114 with respect to the current of the coil 162. When the current is 0, the spool 130 is in the starting point region and the pressure of the output port 114 is high. Therefore, high pressure oil leaks from the feedback chamber 116a into the damper chamber 190, and the pressure in the damper chamber 190 also increases. It gets higher. When the current flows and the spool 130 is in the pressure adjustment region, the pressures of the output port 114 and the feedback port 116 gradually decrease, so that the pressure in the damper chamber 190 also decreases accordingly. When the current increases and the spool stroke reaches the end point region, the input port 112 is closed, so that the pressure in the feedback chamber 116a also becomes normal pressure.

FIG. 4B is a diagram showing an opening area with respect to the movement amount of the spool 130. When in both end regions (start point region and end point region), only the opening area of the orifice 182 is open. Then, when the rod groove 142 approaches the plate 180, the opening area of the gap 186 between the rod groove 142 and the central hole 184 of the plate 180 increases.

As described above, in the pressure control region of the stroke of the spool 130, oil passes through the gap 186 between the plate 180 groove and the central hole 184 in addition to the orifice 182, so that the flow path area is expanded. Therefore, the damper effect can be reduced in the pressure adjustment region of the stroke, and the movement of the spool 130 is not hindered, so that deterioration of responsiveness can be suppressed.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the claims, which naturally belong to the technical scope of the present invention. Understood.

The present invention can be used as a normally open solenoid valve capable of suppressing self-excited vibration.

100 ... Solenoid valve, 110 ... Sleeve, 112 ... Input port, 114 ... Output port, 114a ... Pressure control chamber, 116 ... Feedback port, 116a ... Feedback chamber, 118 ... Drain port, 118a ... Drain chamber, 120 ... Adjuster, 122 ... Discharge port, 124 ... Flange, 124a ... Discharge port, 130 ... Spool, 132 ... 1st land, 134 ... 2nd land, 136 ... 3rd land, 138 ... Small diameter part, 140 ... Small diameter shaft, 142 ... Rod groove, 150 ... spring, 150a ... spring chamber, 160 ... solenoid part, 160a ... caulking part, 162 ... coil, 164 ... flanger, 166 ... oil discharge path, 168 ... pusher, 170 ... stopper, 172 ... cylindrical boss, 174 ... diameter Directional groove, 176 ... stopper front, 180 ... plate, 182 ... orifice, 184 ... center hole, 186 ... gap, 190 ... damper chamber, 200 ... plate, 202 ... notch, 210 ... plate, 212 ... notch, 220 ... plate, 222 ... cut up, 224 ... gap

Claims (1)

A sleeve with at least an input port, an output port and a drain port,
A spool slidably supported in the sleeve,
A spring that urges the spool toward one side,
An electromagnetic part that drives the spool toward the other, and
In a normally open solenoid valve provided with a stopper arranged on the spool side of the solenoid portion,
A plate provided with an orifice is arranged on the spool side of the stopper, and a plate is arranged.
A damper chamber is formed on the spool side of the plate.
An oil discharge path communicating with the outside is formed on the electromagnetic portion side of the plate.
The damper chamber and the oil discharge path are communicated with each other by the orifice.
Further, a central hole is formed in the center of the plate.
A small diameter shaft inserted into the central hole is provided on the solenoid portion side of the spool.
At the position corresponding to the plate, the outer diameter of the small diameter shaft when the spool is in both ends of the stroke has a shape along the inner diameter of the center hole, and the pressure adjusting region of the stroke has a gap with the center hole. A normally open solenoid valve characterized by having a groove for allowing oil to pass through.

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