Solenoid proportional valve

Abstract

To provide a solenoid proportional valve capable of securing a damper effect and improving vibration resistance even when in use in an oil environment mixed with air.SOLUTION: A solenoid proportional valve 100 includes: a sleeve 102 having at least an input port 120, an output port 122, and a drain port 126; a spool 104 slidably supported in the sleeve; an electromagnetic part 106 driving the spool; a spring 110 energizing the spool toward an initial position; a spring chamber 110a housing the spring in the sleeve; an orifice 130 which is formed in the sleeve and goes through the sleeve to an outside from above the spring chamber; an adjuster 128 which is a bottomed cylinder screwed with one end 108 of the sleeve, contacts the spring, and adjusts a compression amount of the spring; and an inclined surface 142 formed on an inner periphery of the adjuster and inclined toward the orifice.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a proportional solenoid valve having a multi-port sleeve. [Background technology]

[0002] As an example, an solenoid valve has a sleeve and a spool slidably supported inside the sleeve, and displaces the spool by the suction force generated when a solenoid coil in an electromagnetic part attached to the end of the sleeve is excited, thereby outputting a predetermined control pressure.

[0003] Patent Document 1 describes a solenoid valve having a supply pressure chamber communicating with an input port, a first valve chamber communicating with a feedback port, a second valve chamber communicating with an output port, and a spring chamber. In this solenoid valve, the first valve chamber and the second valve chamber are arranged to face each other with the supply pressure chamber in between, and a drain port having a throttle portion (orifice) is connected to the spring chamber.

[0004] In Patent Document 1, the first valve chamber and the second valve chamber are provided adjacent to and facing the supply pressure chamber. This directs the flow of hydraulic oil from the inside to the outside of the spool, reducing the flow force in the opposite direction to the spool displacement. Furthermore, by providing a throttle section in the drain port of the spring chamber, the spool valve is controlled by a damper effect, ensuring resistance to oil vibrations caused by external factors that make the inflow flow rate unstable.

[0005] Patent Document 2 describes a solenoid valve in which an annular oil reservoir groove is engraved on the outer circumferential surface of the sleeve in a portion corresponding to a spring chamber. In this solenoid valve, a throttle hole (orifice) that connects the annular oil reservoir groove to the spring chamber is provided in the lower part of the annular oil reservoir groove, and the upper part of the annular oil reservoir groove is connected to the outside of the fitting hole by a drain passage. The drain passage is formed on the outer circumferential surface of the sleeve from the annular oil reservoir groove toward the end of the sleeve.

[0006] In this solenoid valve, the upper part of the oil reservoir annular groove is connected to the outside of the fitting hole by a drain passage, so the hydraulic oil can be stored up to the upper part of the oil reservoir annular groove and can be reserved in the spring chamber connected by the throttle hole. For this reason, Patent Document 2 states that the spool valve is prevented from self-excited vibration by the damping effect of the hydraulic oil reserved in the spring chamber. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2008-8380 A [Patent Document 2] JP 2006-112514 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, the solenoid valves in Patent Documents 1 and 2 are designed so that oil is released through an orifice that penetrates from the bottom of the spring chamber to the outside. For this reason, if used in an oil environment that contains air (air bubbles), the oil mixed with air will flow into the spring chamber from the bottom, causing air to gradually accumulate in the spring chamber. And since the air that has accumulated in the spring chamber cannot be released, the spring chamber will become filled with air and will not be able to maintain its damping effect, which may result in hydraulic vibration.

[0009] In view of the above problems, the present invention aims to provide an electromagnetic proportional valve that can ensure a damping effect and improve vibration resistance even when used in an oil environment containing air. [Means for solving the problem]

[0010] In order to solve the above problems, a representative configuration of an electromagnetic proportional valve according to the present invention is characterized in that it comprises a sleeve having at least an input port, an output port, and a drain port, a spool slidably supported within the sleeve, an electromagnetic part that drives the spool, a spring that urges the spool toward an initial position, a spring chamber in which the spring is accommodated within the sleeve, an orifice that is formed in the sleeve and penetrates the spring chamber from above to the outside, an adjuster that is a bottomed cylinder that is screwed into the open end of the sleeve and abuts against the spring to adjust the compression amount of the spring, and an inclined surface that is formed on the inner circumference of the adjuster and inclined toward the orifice.

[0011] In the above configuration, the orifice formed in the sleeve penetrates the spring chamber from above to the outside, and the inclined surface formed on the inner circumference of the adjuster is inclined toward the orifice without blocking it. Therefore, even if oil containing air flows into the spring chamber from below, the air moves upward within the spring chamber, is guided toward the orifice by the inclined surface of the adjuster, and is discharged through the orifice to the outside of the spring chamber. Therefore, with the above configuration, the damping effect can be ensured and vibration resistance can be improved even when used in an oil environment containing air (suppression of self-excited vibration).

[0012] The adjuster has a bottom surface formed with a convex portion that protrudes toward the spool inside the spring, and the convex portion preferably protrudes to a position closer to the spool than the end turn of the spring.

[0013] In this way, the convex portion formed on the bottom surface of the adjuster protrudes to a position closer to the spool than the end coil of the spring, which prevents air from accumulating in the end coil of the spring, and therefore allows air that has flowed into the spring chamber to be more reliably discharged to the outside through the orifice.

[0014] It is preferable that the outer peripheral surface of the sleeve has a large diameter portion sealed by a specified housing, and a small diameter portion communicating with the outside via a gap between the housing, and is further provided with a through hole penetrating from above the large diameter portion of a drain chamber formed in the sleeve and communicating with a drain port below, and a communicating groove formed in the outer peripheral surface of the sleeve communicating from the through hole to the small diameter portion.

[0015] As a result, even if air flows in from below the drain port, the air moves upward within the drain chamber, passes through the through hole, is guided to the large diameter portion on the outer circumferential surface of the sleeve, is further guided by the communicating groove to the small diameter portion, and is discharged to the outside through the gap between the small diameter portion and the housing. In this way, the air that has flowed in from below the drain port can be discharged to the outside. Effect of the Invention

[0016] According to the present invention, it is possible to provide an electromagnetic proportional valve that can ensure a damping effect and improve vibration resistance even when used in an oil environment containing air. [Brief description of the drawings]

[0017] [Figure 1] 1 is an overall configuration diagram of an electromagnetic proportional valve according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing a sleeve and an adjuster of the solenoid proportional valve of FIG. 1. [Diagram 3] FIG. 2 is a diagram showing a main part of the solenoid proportional valve of FIG. [Figure 4] FIG. 11 is an overall configuration diagram of an electromagnetic proportional valve according to another embodiment of the present invention. [Diagram 5] FIG. 5 is a diagram showing a sleeve and an adjuster of the solenoid proportional valve of FIG. 4. [Figure 6] FIG. 5 is a diagram showing a main part of the solenoid proportional valve of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0019] 1 is an overall configuration diagram of an electromagnetic proportional valve 100 according to an embodiment of the present invention. The electromagnetic proportional valve 100 is a proportional valve that can adjust the flow rate of oil according to the valve opening degree, and is a normally open type valve that is open under normal conditions (when not energized) and closes when driven (when energized).

[0020] The solenoid proportional valve 100 includes a substantially cylindrical sleeve 102 (see FIG. 2), a spool 104 slidably supported inside the sleeve 102, and an electromagnetic part 106 that drives the spool 104. In FIG. 1, the solenoid proportional valve 100 is shown in a non-energized state above the central axis O, and in a powered state below the central axis O.

[0021] A spring 110 is mounted in one end 108 of the sleeve 102. The electromagnetic portion 106 is attached to the other end 112 of the sleeve 102. The spring 110 biases the spool 104 towards the electromagnetic portion 106, i.e., towards the initial position.

[0022] The electromagnetic portion 106 has a coil 114 and a plunger 116, and when the coil 114 is excited, the plunger 116 is moved, thereby moving the spool 104 toward the spring 110. A stopper 118 is provided on the spool 104 side of the electromagnetic portion 106, and is abutted against the other end 112 of the sleeve 102.

[0023] The sleeve 102 has an input port 120 to which hydraulic oil is supplied, an output port 122 that outputs hydraulic oil when the solenoid proportional valve 100 is open, a feedback port 124, and a drain port 126. The output port 122 branches so that a portion of the hydraulic oil is returned to the feedback port 124. The inner diameter around the feedback port 124 is wider, and this is called a feedback chamber 124a. The inner diameter around the drain port 126 is wider, and this is called a drain chamber 126a.

[0024] The inner diameter of the periphery of the spring 110 is also wider, and this is called a spring chamber 110a. The spring chamber 110a is a space that houses the spring 110 within the sleeve 102. The spring 110 abuts against the adjuster 128 within the spring chamber 110.

[0025] The adjuster 128 is a cylinder with a bottom that is screwed into one end 108 of the sleeve 102 (see FIG. 2), and is rotated to adjust the amount of compression of the spring 110, thereby adjusting the load of the spring 110. Note that one end 108 of the sleeve 102 is an open end as shown in FIG. 2. An orifice 130 is formed in the sleeve 102. The orifice 130 penetrates the spring chamber 110a from above to the outside as shown in FIG.

[0026] In addition, the spool 104 is formed with a plurality of steps of different diameters for opening and closing each port of the sleeve 102. The first land 132 opens and closes the drain port 126. The second land 134 opens and closes the input port 120. The third land 136 faces the feedback chamber 124a.

[0027] When the solenoid portion 106 is not excited, the spool 104 is pushed by the spring 110 and positioned toward the solenoid portion 106 as shown in the upper part of Fig. 1. At this time, the input port 120 and the output port 122 communicate with each other, and hydraulic oil is output. In this state, the solenoid proportional valve 100 is said to be open (normally open).

[0028] When the solenoid portion 106 is excited, the spool 104 is pushed by the plunger 116 of the solenoid portion 106 and moves to the left as shown in the lower part of FIG. 1. At this time, the input port 120 is closed by the second land 134, and the output port 122 and the drain port 126 are connected to each other. As a result, the pressure in the output port 122 becomes the same as that in the drain port 126, which is normal pressure, and no pressure is transmitted to the output side. This state is said to be the solenoid proportional valve 100 is closed.

[0029] Here, the pressure applied to the feedback port 124 is the same as that of the output port 122. When the solenoid proportional valve 100 is closed, the feedback port 124 is also at normal pressure, but when the solenoid proportional valve 100 is open, the pressure (high pressure) of the input port 120 is also applied to the feedback port 124.

[0030] The diameter of the second land 134 is larger than that of the third land 136, and the difference in diameter changes the pressure-receiving area, so that the spool 104 is biased toward the spring 110 by the internal pressure of the feedback chamber 124a. This biasing force is called a feedback force. As a result, the feedback force and the plunger thrust of the electromagnetic part 106 are configured to balance with the spring force.

[0031] Fig. 2 is a diagram showing the sleeve 102 and the adjuster 128 of the electromagnetic proportional valve 100 of Fig. 1. Fig. 3 is a diagram showing a main part of the electromagnetic proportional valve 100 of Fig. 1. Note that Fig. 3 shows the electromagnetic proportional valve 100 shown above the central axis O of Fig. 1 in a non-energized state.

[0032] The adjuster 128 has a bottom surface 140 and an inclined surface 142 as shown in Fig. 2. A convex portion 144 is formed on the bottom surface 140 of the adjuster 128. The convex portion 144 protrudes by a dimension La from the bottom surface 140 toward the spool 104 inside the spring 110 as shown in Fig. 3.

[0033] In addition, the end turn 111 of the spring 110 abuts against the bottom surface 140 of the adjuster 128. The end turn 111 of the spring 110 has a length of dimension Lb from the bottom surface 140 when in contact with the bottom surface 140 (two turns in the figure). As shown in Fig. 3, dimension La is larger than dimension Lb, and the convex portion 144 protrudes to a position closer to the spool 104 than the end turn 111 of the spring 110.

[0034] An inclined surface 142 is formed on the inner circumference of the adjuster 128. The inclined surface 142 is inclined toward the orifice 130 formed in the sleeve 102 and extends further to the front of the orifice 130 so as not to block the orifice 130. The outer circumferential surface 148 of the sleeve 102 has a large diameter portion 150 and a small diameter portion 152 shown in FIG. 2. The large diameter portion 150 is sealed by a predetermined housing 154 as shown in FIG. 3. The small diameter portion 152 communicates with the outside via a gap 156 between it and the housing 154.

[0035] In addition, the orifice 130 penetrates the spring chamber 110a from above to the outside, and communicates with the small diameter portion 152 of the sleeve 102. Therefore, in the solenoid proportional valve 100, as shown by the arrow A in Figure 3, the hydraulic oil can be sucked in from the outside and discharged to the outside through the orifice 130 in response to the volumetric fluctuation of the spring chamber 110a caused by the movement of the spool 104.

[0036] In addition, in the solenoid proportional valve 100, not only does the orifice 130 penetrate from above the spring chamber 110a to the outside, but the inclined surface 142 formed on the inner circumference of the adjuster 128 is inclined toward the orifice 130 without blocking the orifice 130.

[0037] For this reason, even if the solenoid proportional valve 100 is used in an oil environment in which oil containing air (air bubbles) flows in from the drain port 126, the air moves upward within the spring chamber 110a as shown by the arrow B, and is guided toward the orifice 130 by the inclined surface 142 of the adjuster 128. Furthermore, the air passes through the orifice 130 as shown by the arrow C, and is guided from the spring chamber 110a to the small diameter portion 152 of the sleeve 102, and is further discharged to the outside through the gap 156 with the housing 154.

[0038] As a result, even if the solenoid proportional valve 100 is used in an oil environment containing air, air does not accumulate in the spring chamber 110a, and the inside of the spring chamber 110a can always be filled with hydraulic oil, ensuring a damping effect. This makes it possible to mitigate high-speed movement of the spool 104, suppress self-excited vibration of the spool 104, and improve vibration resistance.

[0039] Furthermore, in the solenoid proportional valve 100, the convex portion 144 formed on the bottom surface 140 of the adjuster 128 protrudes to a position closer to the spool 104 than the end turn 111 of the spring 110, so that it is possible to prevent air from accumulating in the end turn 111 of the spring 110. This makes it possible to more reliably discharge air that has flowed into the spring chamber 110a to the outside through the orifice 130.

[0040] Fig. 4 is an overall configuration diagram of a proportional solenoid valve 100A in another embodiment of the present invention. Fig. 5 is a diagram showing a sleeve 102A and an adjuster 128 of the proportional solenoid valve 100A in Fig. 4. Fig. 6 is a diagram showing a main part of the proportional solenoid valve 100A in Fig. 4.

[0041] The solenoid proportional valve 100A differs from the solenoid proportional valve 100 in that, instead of the above-mentioned sleeve 102, a sleeve 102A having a through hole 158 and a communication groove 160 shown in Fig. 4 is provided. The through hole 158 is formed in the sleeve 102A, and passes through the drain chamber 126a from above to the large diameter portion 150 as shown in Fig. 6. The communication groove 160 is formed in the outer circumferential surface 148A of the sleeve 102A, and passes from the through hole 158 to the small diameter portion 152 as shown in Figs. 5 and 6.

[0042] As a result, even if the solenoid proportional valve 100A is used in an oil environment containing air and air flows in from below the drain port 126, the air moves upward within the drain chamber 126a, as shown by arrow D in Figure 6, and is guided through the through hole 158 to the large diameter portion 150 on the outer circumferential surface 148A of the sleeve 102A.

[0043] Furthermore, as shown by arrow D, the air is guided from large diameter portion 150 to small diameter portion 152 by communication groove 160 and is discharged to the outside through gap 156 between small diameter portion 152 and housing 154. In this way, the solenoid proportional valve 100A not only discharges air that has flowed into spring chamber 110a to the outside through orifice 130, but also discharges air that has flowed from drain port 126 into drain chamber 126a to the outside through through hole 158 and communication groove 160.

[0044] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an example. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that such examples also naturally belong to the technical scope of the present invention. [Industrial Applicability]

[0045] The present invention can be utilized as an electromagnetic proportional valve having a sleeve in which a plurality of ports are formed. [Explanation of symbols]

[0046] 100, 100A... solenoid proportional valve, 102, 102A... sleeve, 104... spool, 106... solenoid part, 108... one end of sleeve, 110... spring, 111... spring end winding, 110a... spring chamber, 112... other end of sleeve, 114... coil, 116... plunger, 118... stopper, 120... input port, 122... output port, 124... feedback port, 126... drain port, 124a... feedback drain chamber, 126a...drain chamber, 128...adjuster, 130...orifice, 132...first land, 134...second land, 136...third land, 140...bottom surface of adjuster, 142...sloping surface of adjuster, 144...convex portion of adjuster, 148, 148A...outer peripheral surface of sleeve, 150...large diameter portion of sleeve, 152...small diameter portion of sleeve, 154...housing, 156...gap, 158...through hole of sleeve, 160...communicating groove of sleeve

Claims

1. a sleeve having at least an input port, an output port, and a drain port; a spool slidably supported within the sleeve; an electromagnetic portion that drives the spool; A spring biases the spool toward an initial position; a spring chamber in which the spring is accommodated within the sleeve; an orifice formed in the sleeve and penetrating the spring chamber from above to the outside; an adjuster which is a bottomed cylinder that is screwed into the open end of the sleeve and abuts against the spring to adjust the compression amount of the spring; an inclined surface formed on an inner periphery of the adjuster and inclined toward the orifice.

2. A convex portion is formed on the bottom surface of the adjuster, the convex portion protruding toward the spool on the inside of the spring, 2. The proportional solenoid valve according to claim 1, wherein the protrusion protrudes to a position closer to the spool than the end coil of the spring.

3. the outer circumferential surface of the sleeve has a large diameter portion sealed in a predetermined housing and a small diameter portion communicating with the outside via a gap between the small diameter portion and the housing; a through hole formed in the sleeve and penetrating the large diameter portion from an upper direction of a drain chamber, the drain chamber communicating with a drain port at the lower portion; 3. The solenoid proportional valve according to claim 1, further comprising: a communication groove formed on an outer circumferential surface of the sleeve, the communication groove extending from the through hole to the small diameter portion.

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