阅读说明：本技术 比例电磁阀和流体压系统 (Proportional solenoid valve and fluid pressure system ) 是由 岩崎仁 于 2021-03-18 设计创作，主要内容包括：本发明提供一种比例电磁阀和流体压系统。本发明的比例电磁阀具备阀柱、电驱动部、以及检测部。阀柱具有：第1端；第2端,其位于与第1端相反的一侧；以及沿着轴向的贯通孔。在阀柱中,从第1端向贯通孔供给来自泵端口的工作油。电驱动部设置于阀柱的第2端侧,驱动阀柱。检测部设置于电驱动部,检测泵端口的压力。(The invention provides a proportional solenoid valve and a fluid pressure system. The proportional solenoid valve of the present invention includes a spool, an electric drive unit, and a detection unit. The spool has: a 1 st end; a 2 nd end located on the opposite side of the 1 st end; and a through hole along the axial direction. In the spool, the working oil from the pump port is supplied from the 1 st end to the through hole. The electric drive unit is provided on the 2 nd end side of the spool and drives the spool. The detection unit is provided in the electric drive unit and detects a pressure at the pump port.)

1. A proportional solenoid valve, wherein,

the proportional solenoid valve includes:

a spool having a 1 st end, a 2 nd end located on the opposite side of the 1 st end, and a through hole along an axial direction, the spool being configured to supply working oil from a pump port from the 1 st end to the through hole;

An electric drive unit provided on the 2 nd end side of the spool and driving the spool; and

and a detection unit provided in the electric drive unit and detecting a pressure at the pump port.

2. The proportional solenoid valve of claim 1,

the electric drive unit includes a rod that abuts the 2 nd end of the spool and presses the spool.

3. The proportional solenoid valve of claim 1 or 2,

the proportional solenoid valve has:

a housing that houses the spool and has a spool hole;

a discharge port extending radially of the spool bore toward the spool; and

an actuator port extending radially of the spool bore toward the spool,

the spool has:

a 1 st flow path connecting the exhaust port and the actuator port; and

a 2 nd flow path connecting the pump port and the actuator port.

4. The proportional solenoid valve of claim 3,

the spool connects the discharge port and the actuator port and blocks the pump port when neutral, which is not driven by the electric drive,

the spool connects the pump port and the actuator port and blocks the discharge port upon being driven by the electric drive.

5. The proportional solenoid valve of claim 1,

the detection unit detects a force transmitted from the spool on which the pressure acts to a rod that presses the spool.

6. The proportional solenoid valve of claim 1,

the electric drive unit includes a housing that houses a rod that presses the spool and the detection unit.

7. A fluid pressure system in which, in a fluid pressure system,

the fluid pressure system includes:

a fluid pressure pump that generates fluid pressure using a working fluid;

a fluid pressure valve device that switches an output target of the working fluid;

an actuator driven by the working fluid supplied from the fluid pressure valve device; and

a proportional solenoid valve, comprising: a spool having a 1 st end, a 2 nd end located on the opposite side of the 1 st end, and a through hole along an axial direction, the spool being configured to supply working oil from a pump port from the 1 st end to the through hole; an electric drive unit provided at the 2 nd end of the spool and driving the spool; and a detection unit provided in the electric drive unit and detecting a pressure at the pump port.

Technical Field

The invention relates to an automatic proportional solenoid valve and a fluid pressure system suitable for hydraulic control.

Background

As for a hydraulic circuit for a construction machine, a fluid pressure system provided with a hydraulic circuit having an electrically controlled proportional solenoid valve is increasing. The proportional solenoid valve includes, for example: a solenoid; a lever driven by the solenoid; a spool that is pushed and moved by a rod; and a return spring for returning the spool to an original position. The spool blocks and connects ports connected to a pilot flow path to which hydraulic oil is supplied from the pump, an actuator port connected to an actuator to be driven, and a drain port connected to a tank for storing return oil.

Documents of the prior art

Patent document

Patent document 1: japanese Kokukai Hei 04-036183

Disclosure of Invention

Problems to be solved by the invention

In order to electrically control the proportional solenoid valve, it is necessary to detect the pressure of the working oil. For example, a proportional solenoid valve described in patent document 1 is provided with a drain port, an actuator port, and a pilot port in a direction orthogonal to the moving direction of a spool. In the proportional solenoid valve having such a configuration, when the pressure of the actuator port and the pressure of the pilot port are detected, a pressure detecting portion needs to be provided separately from the proportional solenoid valve.

A proportional solenoid valve having another structure has an actuator port along the moving direction of the spool, and a discharge port and a pilot port are provided in a direction orthogonal to the moving direction of the spool. In the proportional solenoid valve having such a structure, the actuator port of the spool opposes the rod driven by the electric drive portion that drives the spool, and therefore the control pressure of the actuator port acts on the electric drive portion. Therefore, the pressure of the actuator port can be detected at the electric drive portion. However, the proportional solenoid valve having such a structure cannot detect the pressure of the pilot port as the initial pressure.

The invention aims to provide a proportional solenoid valve and a fluid pressure system which can simply detect the pressure of working oil supplied from a pump of the working oil.

Means for solving the problems

The proportional solenoid valve according to an aspect of the present invention includes: a spool having a 1 st end, a 2 nd end located on the opposite side of the 1 st end, and a through hole along an axial direction, the spool being configured to supply working oil from a pump port from the 1 st end to the through hole; an electric drive unit provided on the 2 nd end side of the spool and driving the spool; and a detection unit provided in the electric drive unit and detecting a pressure at the pump port.

According to the aspect of the present invention, the pump port is connected to the through hole formed in the spool, and the detection unit detects the force applied to the spool, thereby being able to detect the pilot pressure of the hydraulic oil flowing through the pump port RP.

In the proportional solenoid valve according to an aspect of the present invention, the electric drive unit may include a rod that abuts the 2 nd end side of the spool to press the spool.

The proportional solenoid valve according to an aspect of the present invention may include: a housing that houses the spool and has a spool hole; a discharge port extending radially of the spool bore toward the spool; and an actuator port extending radially of the spool bore toward the spool. The spool may have: a 1 st flow path connecting the exhaust port and the actuator port; and a 2 nd flow path connecting the pump port and the actuator port.

In the proportional solenoid valve according to an aspect of the present invention, the spool may connect the discharge port and the actuator port and block the pump port when the proportional solenoid valve is in a neutral state in which the proportional solenoid valve is not driven by the electric drive unit, or the spool may connect the pump port and the actuator port and block the discharge port when the proportional solenoid valve is driven by the electric drive unit.

In the proportional solenoid valve according to an aspect of the present invention, the detection unit may detect a force transmitted from the spool on which the pressure acts to a rod that presses the spool.

In the proportional solenoid valve according to an aspect of the present invention, the electric drive unit may include a solenoid that electromagnetically drives the rod. The detection unit may be configured to detect a force generated in a rod pressing the spool that transmits the pressure.

In the proportional solenoid valve according to an aspect of the present invention, the electric drive unit may include a housing that houses a rod that presses the spool and the detection unit.

A fluid pressure system according to an aspect of the present invention includes: a fluid pressure pump that generates fluid pressure using a working fluid; a fluid pressure valve device that switches an output target of the working fluid; an actuator driven by the working fluid supplied from the fluid pressure valve device; and a proportional solenoid valve provided with: a spool having a 1 st end, a 2 nd end located on the opposite side of the 1 st end, and a through hole along an axial direction, the spool being configured to supply working oil from a pump port from the 1 st end to the through hole; an electric drive unit provided at the 2 nd end of the spool and driving the spool; and a detection unit provided in the electric drive unit and detecting a pressure at the pump port.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the aspect of the present invention, the pressure of the hydraulic oil supplied from the pump of the hydraulic oil can be easily detected.

Drawings

Fig. 1 is a diagram showing a schematic configuration of a construction machine according to an embodiment of the present invention.

Fig. 2 is a diagram showing a configuration of a hydraulic system in an embodiment of the present invention.

Fig. 3 is a block diagram showing a configuration related to control of a proportional solenoid valve in the embodiment of the present invention.

Fig. 4 is a cross-sectional view showing the structure of a proportional solenoid valve in the embodiment of the present invention.

Fig. 5 is a perspective view showing the structure of a spool in the embodiment of the present invention.

Description of the reference numerals

1. A hydraulic system; 100. a construction machine; 101. a revolving body; 102. a traveling body; 103. a driver seat; 104. a movable arm; 105. a bucket rod; 106. a bucket; 108. an operation section; 120. an engine; 121. an output shaft; 130. a hydraulic pump; 140. an actuator; 150. a proportional solenoid valve; 151. an electric drive section; 152. an electromagnetic coil; 153. a rod; 154. a housing; 155. a main body; 160. a tank; 170. a detection unit; 200. a control device; 300. an overflow valve; A. block 1; B. a 2 nd block; C. dividing the noodles; G. a return spring; H. a valve post bore; h1, 1 st through hole; h2, No. 2 through hole; h3, diameter-expanding section; h4, ring chamber 1; h5, annular chamber 2; HD. A step; q, tubing; RA, actuator port; RD, discharge port; RP, pump port; s, a valve column; s3, a projection; s4, steps; s5, steps; s6, flow path 2; SH, through holes; SM, a groove; SN, notch.

Detailed Description

Next, embodiments of the present invention will be described with reference to the drawings.

(construction machine)

As shown in fig. 1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a revolving structure 101 and a traveling structure 102. Revolving unit 101 is provided on traveling unit 102 so as to be rotatable. The revolving structure 101 is provided with a hydraulic system 1.

Rotator 101 includes: a driver seat 103 on which an operator can ride; a boom 104 having one end connected to the revolving unit 101 so as to be swingable; an arm 105 having one end connected to the other end (distal end) of the boom 104 so as to be swingable; a bucket 106 connected to the other end (tip end) of arm 105 so as to be swingable; and an operation unit 108 for an operator to operate. Further, a hydraulic system 1 is provided in the revolving unit 101. The revolving unit 101, the boom 104, the arm 105, and the bucket 106 are driven by the working fluid supplied from the hydraulic system 1.

(Hydraulic System)

As shown in fig. 2, the hydraulic system 1 (fluid pressure system) includes: an engine 120 as a driving source; a hydraulic pump 130 driven by the engine 120; a plurality of actuators 140 that operate each part of the construction machine 100; a control valve 500 that switches the operation of the plurality of actuators 140; a proportional solenoid valve 150 that applies a control pressure of the working fluid to the control valve 500; a tank 160 storing a working fluid; a detection unit 170 that detects the hydraulic pressure; a control device 200 that adjusts the proportional solenoid valve 150; and a relief valve 300 for pressure adjustment. In the present embodiment, the case where the working oil is used as the working fluid is exemplified, but a fluid other than the working oil may be used. The hydraulic system 1 may be applied not only to a construction machine but also to other devices that generate fluid pressure using a working fluid, such as a hydraulic press.

The engine 120 is an internal combustion engine using gasoline fuel or diesel fuel. The engine 120 includes an output shaft 121, and the output shaft 121 is coupled to the hydraulic pump 130. A pipe Q is connected to the hydraulic pump 130. The hydraulic pump 130 (fluid pressure pump) generates fluid pressure using the working fluid. The hydraulic pump 130 is driven by the output shaft 121 to circulate the working fluid to the pipe Q. A control valve 500 and a proportional solenoid valve 150 are connected to the pipe Q.

In the present embodiment, the engine 120 is used as a drive source for the working fluid, but an electric motor using a power supply device such as a battery as an electric power source may be used as the drive source in addition to the engine 120. Further, engine 120 may be used as a generator that charges a battery and uses the battery as an electric power source.

The control valve 500 (fluid pressure valve device) switches the output destination of the working fluid. A plurality of actuators 140 are connected to the control valve 500 via branched pipes Q. The control valve 500 is provided in plural, and supplies the working fluid to the plural actuators 140 by switching the hydraulic pressure of the working fluid flowing through the pipe Q by the plural valves in accordance with the switching operation of the operation unit 108. The plurality of actuators 140 drive the revolving unit 101, the boom 104, the arm 105, the bucket 106, and the like. The relief valve 300 releases the pressure when the pressure in the flow path becomes equal to or higher than a predetermined value set in advance in the hydraulic circuit of the hydraulic system 1. The hydraulic fluid from the hydraulic pump 130 based on the operation amount of the operation unit 108 is supplied to the proportional solenoid valve 150.

As shown in fig. 3, the controller 200 controls the proportional solenoid valve 150 in accordance with the operation amount of the operation unit 108. The control device 200 generates a control signal according to the operation amount of the operation unit 108. The proportional solenoid valve 150 controls the valve opening degree in accordance with the control signal, adjusts the flow rate of the hydraulic oil from the hydraulic pump 130 supplied to the control valve 500, and drives the actuator 140.

Proportional solenoid valve 150 is provided with a detection unit 170 for detecting the pilot pressure. As described later, the detection unit 170 detects, for example, a pilot pressure of the hydraulic oil flowing through the pump port RP connected to the proportional solenoid valve 150. The detection value detected by the detection unit 170 is fed back to the control device 200. Control device 200 controls proportional solenoid valve 150 based on the detection value detected by detection unit 170.

As shown in fig. 4 and 5, proportional solenoid valve 150 includes: an electrically driven electric drive section 151; a spool S driven by the electric drive unit 151; a main body 155 that houses the spool S; and a return spring G that restores the position of the moved spool S. The spool S has: a 1 st end; a 2 nd end S2 (the other end S2 discussed later) located on the opposite side of the 1 st end S1 (the one end S1 discussed later); and a through hole SH along the axial direction. In the spool S, the working oil from the pump port RP is supplied from the 1 st end S1 to the through hole SH.

The electric drive unit 151 includes, for example: an electromagnetic coil 152 (solenoid) as a drive source; a lever 153 driven by the solenoid 152; a detection unit 170; and a case 154 as an exterior body. The housing 154 is formed in such a manner as to cover an opening of a post hole H, which will be discussed later, formed in the main body 155.

The electromagnetic coil 152 is formed in a cylindrical shape by winding a copper wire around an iron core. The electromagnetic coil 152 generates a magnetic field by applying current to the copper wire. The rod 153 is formed of metal into a rod shape. The rod 153 is also referred to as a plunger. The rod 153 has a projection 153T projecting in the radial direction.

The rod 153 has one end 153A (1 st rod end) and the other end 153B (2 nd rod end). The other end S2 (No. 2) of the spool S abuts on the side of the one end 153A. The rod 153 abuts on the other end S2 side of the spool S having an opening communicating with the pump port RP formed therein. The projection 153T is disposed so as to be offset toward the other end 153B with respect to the neutral axis L of the electromagnetic coil 152 when viewed in a cross-sectional view in the axial direction.

The rod 153 is disposed slidably in the electromagnetic coil 152 in the axial direction. When the electromagnetic coil 152 is energized, the rod 153 is attracted by the magnetic field generated from the electromagnetic coil 152 and moves in the direction perpendicular to the neutral axis L of the electromagnetic coil 152 when viewed in the axial cross-sectional direction of the electromagnetic coil 152. At this time, the rod 153 pushes the other end S2 of the spool S. The solenoid 152 proportionally controls the amount of current flow according to the operation amount of the operation unit 108, and adjusts the amount of protrusion of the lever 153.

The spool S is movably accommodated in a spool hole H formed in the body 155. The main body 155 is a housing constituting the hydraulic system 1, and has a spool hole H. The main body 155 may be formed by machining a housing, not shown, that constitutes the hydraulic system 1. The main body 155 may be formed separately from the housing and fixed to the housing. The main body 155 is formed of a divided block of, for example, the 1 st block a and the 2 nd block B. A dividing plane C is formed between the 1 st block a and the 2 nd block B. The 1 st block a is disposed on the other end S2 side of the spool S. The 2 nd block B is disposed on the one end S1 (1 st end) side of the spool S.

A spool hole H having a cylindrical space is formed in the main body 155. The stem hole H is formed as a through hole of the 1 st diameter d 1. The spool hole H has a 1 st through hole H1 and a 2 nd through hole H2 formed to have a 1 st diameter d1, a diameter-enlarged portion H3 formed to have a 2 nd diameter d2 larger than the 1 st diameter d1, a 1 st annular chamber H4 and a 2 nd annular chamber H5 formed to have a 3 rd diameter d3 larger than the 2 nd diameter d 2.

The column hole H is composed of a 1 st through hole H1, a 1 st annular chamber H4, an enlarged diameter portion H3, a 2 nd annular chamber H5, and a 2 nd through hole H2, which are formed in this order from the position where the electric drive unit 151 is provided toward the opposite side. The spool hole H is formed such that the 1 st block a side opening of the spool hole H has the 1 st diameter d 1. In the spool hole H, a step HD is formed at the opening on the 2 nd block B side, and the spool hole H is formed to have a 4 th diameter d4 smaller than the 1 st diameter d 1. A return spring G is inserted into the step of the opening on the 2 nd block B side. The return spring G is an elastic member such as a coil spring.

The opening of the 2 nd block B side is formed with a pump port RP discussed later. In block 1 a, a discharge port RD connected to a flow path communicating with the tank 160 is formed in the spool hole H. The discharge port RD is formed to extend radially outward of the stem hole H. The discharge port RD is formed so as to extend in a direction orthogonal to the axial direction of the spool hole H. An annular 1 st annular chamber H4 that is enlarged in the radial direction of the spool hole H is formed at the connecting portion between the discharge port RD and the spool hole H.

The 1 st annular chamber H4 is formed with a 3 rd diameter d3 that is larger than the 2 nd diameter d 2. The discharge port RD is connected to the 1 st annular chamber H4 on the side of the dividing surface C. The 1 st annular chamber H4 is formed to have a diameter larger than that of a protrusion S3 of the spool S, which will be discussed later. The 1 st annular chamber H4 receives a portion of the projection S3 to the step S4 side, which is discussed later. The enlarged diameter portion H3 accommodates the protrusion S3 of the spool S.

In block 2B, an actuator port RA connected to a flow path communicating with the actuator 140 is formed in the spool hole H so as to extend. The actuator port RA is formed to extend radially outward of the spool hole H. The actuator port RA is formed so as to extend in a direction orthogonal to the axial direction of the spool hole H. An annular 2 nd annular chamber H5 that is enlarged in the radial direction of the spool hole H is formed at the connection portion between the actuator port RA and the spool hole H.

The 2 nd annular chamber H5 is formed to be larger than the 2 nd diameter d2 by the 3 rd diameter d 3. The actuator port RA is connected to the 2 nd annular chamber H5 on the side of the dividing plane C. The 2 nd annular chamber H5 receives a portion of the projection S3 to the step S5 side, which is discussed later.

The spool S is formed of, for example, metal into a rod shape. The spool S has a through hole SH formed in the axial direction. The through hole SH communicates with a pump port RP to which the hydraulic oil is supplied from the pump on the side of the one end S1 of the spool S.

A return spring G is interposed between one end of the spool S and the step HD of the spool hole H. The return spring G presses the spool S in the direction of the electric drive unit 151. One end 153A of the rod 153 of the electric drive unit 151 abuts on the other end S2 side of the spool S. At the other end S2, a groove SM is formed to face the through hole SH. The groove SM is formed in a semicircular shape in cross section, for example. The groove SM prevents the opening formed at the other end S2 of the through hole SH from being closed when the one end 153A of the lever 153 abuts. The spool S has a projection S3 formed to expand in diameter in the radial direction in the axial direction.

The protrusion S3 is formed between one end S1 and the other end S2. The projection S3 has a step S4 on the other end S2 side. The pressure of the discharge port RD acts on the step S4. The projection S3 has a step S5 on the one end S1 side. The pressure of the actuator port RA acts on the step S5. The protrusion S3 has a notch SN (1 st flow path) formed in a groove shape in the axial direction. The recess SN is formed with a closed end SN1 on the step S4 side not communicating with the step S4. The recess SN is formed with an open end SN2 communicating with the step S5 on the side of the step S5.

The protrusion S3 has a 2 nd flow path S6 communicating with the through hole SH. The 2 nd flow path S6 is formed in a direction orthogonal to the through hole SH. The 2 nd flow path S6 has one notch SN formed in a direction facing the notch, and two notches SN formed in a direction orthogonal to the notch.

In the neutral state (the state shown on the left side of fig. 4) in which electric drive unit 151 is not driven, spool S connects first annular chamber H4 and second annular chamber H5. In this state, the closed end SN1 of the notch SN is located in the 1 st ring chamber H4, and the open end SN2 is located in the 2 nd ring chamber H5, the notch SN connects the 1 st ring chamber H4 and the 2 nd ring chamber H5. That is, the spool S connects the discharge port RD and the actuator port RA with the recess SN when in neutral.

In this state, the spool S blocks the pump port RP and the 2 nd annular chamber H5. In this state, the 2 nd flow path S6 is accommodated in the enlarged diameter section H3, and the opening of the 2 nd flow path S6 is closed by the wall surface of the enlarged diameter section H3. That is, the spool S blocks the discharge port RD and the actuator port RA from the pump port RP.

The working fluid flowing in from the pump port RP flows through the through hole SH, flows out from the groove SM formed between the other end S2 of the spool S and the one end 153A of the rod 153, fills the housing 154 of the electric drive unit 151, and generates hydraulic pressure. The detection unit 170 detects the pressure (pilot pressure) of the working fluid in the housing 154.

When driven by the electric drive unit 151 (the state shown on the right side of fig. 4), the rod 153 presses the spool S, and the spool S moves in a direction in which the return spring G shortens. The size of the opening of the 2 nd flow path S6 communicating with the 2 nd annular chamber H5 increases according to the amount of movement of the spool S. Thereby, the pump port RP is connected to the 2 nd annular chamber H5, and the flow rate of the hydraulic oil is adjusted. The spool S connects the pump port RP and the actuator port RA, and adjusts the flow rate of the working oil.

At this time, the working fluid flowing in from the pump port RP flows through the 2 nd flow passage S6 and the 2 nd annular chamber H5 from the pump port RP and flows out to the actuator port RA. The pressure (pilot pressure) of the working fluid in casing 154 is lower than that in the neutral state in which electric drive unit 151 is not driven. The detection unit 170 detects the pressure of the working fluid in the housing 154.

When the movement of the spool S is completed, the closed end SN1 of the notch SN is received in the enlarged diameter portion H3. Therefore, the 1 st annular chamber H4 and the 2 nd annular chamber H5 are blocked. That is, the spool S blocks the exhaust port RD and the actuator port RA.

In the state of the spool S, the detection unit 170 detects the force transmitted from the other end S2 of the spool S to the rod 153. The pressure of the working oil supplied from the pump port RP acts on one end S1 of the spool S. Therefore, the detection portion 170 in the housing 154 can directly detect the pressure (pilot pressure) of the pump port RP from the amount of movement of the spool S.

As described above, according to the proportional solenoid valve 150, the pump port RP is connected to the through hole SH formed in the spool S. The detection unit 170 detects a force applied to the rod 153 abutting against the spool S, and can detect the pressure (pilot pressure) of the hydraulic oil flowing through the pump port RP from the amount of movement of the spool S. That is, according to the proportional solenoid valve 150, the detection unit 170 detects the pressure applied to the spool S to which the pump port RP is connected in the moving direction, and therefore, the device configuration for detecting the pilot pressure can be simplified.

The present invention is not limited to the above-described embodiments, and various modifications may be made to the above-described embodiments without departing from the scope of the present invention. For example, in the above embodiment, the main body 155 is divided into the 1 st block a and the 2 nd block B, but the present invention is not limited thereto, and the main body 155 may be divided into three parts.