JP7030678B2 - Control valve - Google Patents

Description

The present invention relates to a control valve that supplies and discharges hydraulic oil by operating a spool.

Patent Document 1 describes a spring (literature) in which a spool is housed in a valve housing (valve body in the document) in the axial direction, and the first land of the spool is brought into contact with a break portion of the valve housing to maintain a closed state. A pressure reducing valve with a spring) is described. In Patent Document 1, the pressure oil supplied to the primary side of the pressure reducing valve is introduced into the spring chamber on the secondary side through the through hole and discharged to the outside of the pressure reducing valve through the spring chamber. ..

Japanese Unexamined Patent Publication No. 2007-249583

However, in the pressure reducing valve of Patent Document 1, when a large flow rate of pressure oil flows, the pressure in the spring chamber on the secondary side rises (a so-called “muffled pressure” is generated in the spring chamber), and the spool closes the through hole. In some cases, it may not be possible to flow a sufficient amount of pressure oil due to the action of the force.

For this reason, there is a demand for a control valve that can smoothly discharge hydraulic oil even when a large flow rate of pressure oil flows.

The characteristic configuration of the control valve according to the present invention is that a spool chamber is formed by a coaxial core with the working shaft core, a pressure port on which the pressure of the hydraulic oil acts, a first drain port for discharging the hydraulic oil, and a hydraulic oil being discharged. The second drain port is arranged along the working shaft core in this order, and the valve housing is formed by communicating these ports with the spool chamber, and the second drain port is housed in the spool chamber. A spool that can be operated in a closed position that closes the pressure port and a discharge position that discharges hydraulic oil flowing from the pressure port into the spool chamber from the spool chamber to the first drain port by opening the pressure port. A spring is provided in the spool chamber, which is accommodated in a portion where the second drain port communicates, and which urges the spool from the side of the discharge position to the side of the closed position, and the spool is a control land portion. The contact land portion and the regulation wall portion are formed along the operating shaft core in this order, and when the spool is in the closed position, the control land portion and the contact land portion are described. By blocking the flow of hydraulic oil from the pressure port to the first drain port and opening the control land portion and the contact land portion when the spool is in the discharge position, the pressure port can be used. The hydraulic oil is discharged from the space between the control land portion and the contact land portion to the first drain port, and the regulation wall portion is provided regardless of whether the spool is in the closed position or the drain position. The point is that the regulation wall portion is configured as a spring receiving member that abuts on the spring and receives the urging force of the spring by suppressing the flow of hydraulic oil from the pressure port to the second drain port.

According to this characteristic configuration, the spool can be held in the closed position by the urging force of the spring. Further, when the spool is operated from the closed position to the discharge position, the hydraulic oil in the space where the spring is arranged in the spool chamber is discharged from the second drain port, so that the spool can be easily operated. .. Further, by setting the spool to the discharge position, the hydraulic oil from the pressure port flows into the spool chamber, and the hydraulic oil flowing into the spool chamber in this way is discharged from the first discharge drain port. That is, when the hydraulic oil flows inside the spool chamber, the regulation wall portion suppresses the phenomenon that the hydraulic oil flows to the second drain port. As a result, even when the flow rate of the hydraulic oil flowing from the pressure port to the spool chamber increases, the pressure (congestion pressure) in the space where the spring is arranged is suppressed from rising and acting on the spool, and the hydraulic oil is suppressed. It is possible to suppress the phenomenon that the flow of the oil is suppressed.
Therefore, a control valve that can smoothly discharge the hydraulic oil even when a large flow rate of pressure oil flows is configured.

As another configuration, the spool chamber may have a guide hole portion that is an inner peripheral surface close to the outer periphery of the regulation wall portion in a region where the spool moves from the closed position to the discharge position.

According to this, the phenomenon that the hydraulic oil flows between the outer periphery of the regulation wall portion and the inner peripheral surface of the guide hole portion is suppressed, and the hydraulic oil that should flow to the first drain port does not flow to the second drain port.

As another configuration, the spool may have a solid structure .

According to this, it is not necessary to specially provide a spring receiving member on the spool.

As another configuration, the spool has a structure in which a plunger is integrally formed at an end opposite to the position where the spring is arranged, and the spool is placed in the closed position by controlling the pressure acting on the plunger. It may be configured to be freely operable with the discharge position.

According to this, the spool can be operated to a position balanced with the urging force of the spring by adjusting the pressure acting on the plunger from the outside of the control valve.

It is a hydraulic circuit diagram of a valve unit. It is sectional drawing of the ascending control valve in a closed position. It is sectional drawing of the rise control valve in a supply position. It is sectional drawing of the ascending control spool. It is an enlarged sectional view of the part of the communication hole of the ascending control valve in an open position. It is sectional drawing of the descending control valve in a closed position. It is sectional drawing of the descending control valve in a discharge position. It is sectional drawing of a solenoid valve. It is sectional drawing which shows the female thread part and the male thread part in a separated state.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
〔overall structure〕
As shown in FIG. 1, a valve housing H has a hydraulic oil supply port Hp to which hydraulic oil is supplied from a hydraulic pump P, a cylinder port Hc connected to a lift cylinder C, and a plurality of discharge ports Hd for discharging hydraulic oil. The valve housing H is provided with a pressure compensating valve Vr, an ascending control valve Vu, an ascending side electromagnetic valve Vuc, a descending control valve Vd, and a descending side electromagnetic valve Vdc to form a valve unit A. There is.

The valve unit A is provided on the vehicle body of the tractor. The hydraulic pump P is driven by an engine (not shown) of the vehicle body, and the lift cylinder C drives a lift arm 1 provided at the rear end of the vehicle body.

In the valve unit A, a main flow path 2 for supplying hydraulic oil from the hydraulic pump P is formed in the valve housing H, and branches from the main flow path 2 so as to compensate the pressure of the hydraulic oil flowing in the main flow path 2. The pressure control flow path 3 is provided with a pressure compensation valve Vr. Further, an ascending control valve Vu is arranged so as to open and close the hydraulic oil flowing in the main flow path 2, and a descending control valve Vd is arranged in the branch flow path 4 branching from the main flow path 2.

The ascending control valve Vu is operated by a pilot pressure controlled by the ascending solenoid valve Vuc, and an ascending control pilot flow path 5 is formed between the ascending control valve Vu and the ascending solenoid valve Vuc.

Similarly, the descending control valve Vd is operated by the pilot pressure controlled by the descending solenoid valve Vdc, and the descending control pilot flow path 6 is formed between the descending control valve Vd and the descending solenoid valve Vdc. ..

The pressure compensation valve Vr has a compensation function of maintaining the pressure of the hydraulic oil supplied from the hydraulic oil supply port Hp at a set value regardless of the load acting on the lift cylinder C. The ascending solenoid valve Vuc generates a pilot pressure corresponding to the supplied current value, and causes the generated pilot pressure to act on the ascending control pilot flow path 5. Further, the descending solenoid valve Vdc generates a pilot pressure corresponding to the supplied current value, and causes the generated pilot pressure to act on the descending control pilot flow path 6.

The lift arm 1 is supported by a rotary tillage device and a working device such as a plow in a suspended state, and the vehicle body is provided with a control device (not shown) for controlling the raising and lowering of the working device. This control device acquires information such as the ground height of the work device or the traction load acting on the work device, sets the target posture of the lift arm 1, and raises the solenoid valve Vuc so as to reach this target posture. And the elevating control that controls the descending solenoid valve Vdc is realized.

[Rise control valve]
As shown in FIGS. 2 to 4, an ascending spool chamber 11 is formed in a coaxial core with the first shaft core X1 with respect to the valve housing H, and the ascending spool chamber 11 has a pump port 12 and a discharge port 13. Is formed in a communication state. The ascending control valve Vu is configured to accommodate the ascending control spool 14 and the ascending side spring 15 in the ascending side spool chamber 11.

The pump port 12 is formed in the main flow path 2 at a position where hydraulic oil is supplied from the hydraulic oil supply port Hp, and the discharge port 13 is formed in the main flow path 2 at a position communicating with the cylinder port Hc. There is.

The ascending control valve Vu has a structure in which the ascending spool chamber 11 has a first spool hole 11a, a second spool hole 11b, and a third spool hole 11c arranged along the first shaft core X1 in this order. The first spool hole 11a, the second spool hole 11b, and the third spool hole 11c are formed with a circular cross-sectional shape centered on the first shaft core X1 and having the same inner diameter.

The first spool hole 11a is adjacent to the space in which the ascending side spring 15 is arranged, and the ascending side pressure receiving space 16 is adjacent to the position adjacent to the third spool hole 11c. A discharge port 13 is arranged between the first spool hole 11a and the second spool hole 11b, and a pump port 12 is arranged between the second spool hole 11b and the third spool hole 11c.

The rise control spool 14 is formed with a first land portion 14a that is internally fitted into the first spool hole 11a and a second land portion 14b that is internally fitted from the second spool hole 11b to the third spool hole 11c. At the same time, an ascending-side plunger 14c having the same diameter as the second land portion 14b is integrally formed at a position connected to the second land portion 14b.

The ascending control spool 14 has a columnar shape as a whole centered on the spool axis (not shown), and the spool axis is the first axis X1 with the ascending control spool 14 inserted in the ascending spool chamber 11. Match. The above-mentioned second land portion 14b is formed in a cylindrical shape around a spool shaft core (corresponding to the first shaft core X1). The second land portion 14b is formed with a predetermined wall thickness, and a plurality of communication holes 17 having a plurality of through holes and different opening areas are formed in the second land portion 14b so as to communicate the internal space and the external space. .. The plurality of communication holes 17 are all formed in a posture orthogonal to the first axis X1.

That is, three types of communication holes 17 having different opening diameters are used, and large-diameter communication holes 17 are arranged side by side along the circumferential direction of the second land portion 14b, and are arranged in parallel in this way. By arranging the communication holes 17 having a small diameter between the communication holes 17 having a diameter, the cross-sectional area of the opening through which the hydraulic oil can flow is expanded.

Further, it is formed in a positional relationship so that any opening of the plurality of communication holes 17 is exposed in a directional view from any direction orthogonal to the first axis X1.

In this ascending control valve Vu, when the pilot pressure does not act from the ascending solenoid valve Vuc to the ascending side pressure receiving space 16, the ascending control spool 14 is maintained in the closed position shown in FIG. 2 by the urging force of the ascending side spring 15. To. Further, when the pilot pressure acts from the ascending solenoid valve Vuc to the ascending pressure receiving space 16, the ascending control spool 14 moves to a position where the urging force of the ascending spring 15 and the pilot pressure are balanced as shown in FIG. Activates and reaches the supply position.

When the ascending control spool 14 is in the closed position, a part of the plurality of communication holes 17 communicates with the pump port 12, but the plurality of communication holes 17 are blocked by the second spool hole 11b and the discharge port. It is maintained in a state where it does not communicate with 13.

On the other hand, when the ascending control spool 14 reaches the supply position, a part of any one of the plurality of communication holes 17 communicates with the discharge port 13, and the remaining part of the plurality of communication holes 17 is communicated with the discharge port 13. Is in a state of communicating with the pump port 12. As a result, the hydraulic oil from the pump port 12 flows from the communication hole to the internal space of the second land portion 14b, and further, the hydraulic oil in the internal space flows from the communication hole to the external space and is supplied to the discharge port 13.

In particular, the supply position refers to a plurality of positions included in the region where the hydraulic oil from the pump port 12 is sent to the discharge port 13, and the pilot pressure acting from the ascending solenoid valve Vuc in the supply position has increased. In the position in, the supply amount of hydraulic oil is increased as compared with the position where the pilot pressure is low.

In this ascending control valve Vu, when the current for driving the ascending solenoid valve Vuc is increased, the operating amount of the ascending control spool 14 also increases in accordance with the increase in the driving current. Therefore, when the ascending control spool 14 is in the supply position, the amount of hydraulic oil supplied from the cylinder port Hc to the lift cylinder C is increased in response to the increase in the drive current, and the ascending operation of the lift arm 1 is performed at high speed. Realize the conversion.

In particular, as shown in FIG. 5, since a plurality of communication holes are formed in a posture orthogonal to the first shaft core X1, the flow path resistance when hydraulic oil flows through the communication holes is small, and the rise control valve Vu to the cylinder. It is possible to increase the hydraulic oil supplied to the port Hc. That is, in the present embodiment, a plurality of communication holes 17 having different opening areas are opened in a direction substantially perpendicular to the first axis X1. Since the outflow angle of the hydraulic oil flowing out from these communication holes 17 is close to perpendicular to the first shaft core 17, the fluid force acting on the ascending control spool 14 can be reduced. As a result, it is possible to suppress the action of the fluid force of the hydraulic oil in the direction of blocking the rise control spool 14, and it is possible to appropriately control the flow rate of the hydraulic oil even when the flow rate of the hydraulic oil increases.

[Descent control valve]
As shown in FIGS. 6 and 7, the lowering control valve Vd has a pressure port 22 in a lowering side spool chamber 21 formed of a second shaft core X2 (an example of an operating shaft core) and a coaxial core in the valve housing H. , The first drain port 23 and the second drain port 24 are formed along the second shaft core X2 (operating shaft core) in this order, and the lowering control spool 25 and the lowering control spool 25 are formed in the lowering side spool chamber 21. It is configured to accommodate the lowering side spring 26.

The pressure port 22 communicates with the cylinder port Hc, and the first drain port 23 and the second drain port 24 each communicate with the discharge port Hd.

In the lowering side spool chamber 21, a guide hole portion 21a, an abutting portion 21b, a control hole portion 21c, and a plunger hole portion 21d are formed in this order along the second shaft core X2.

In this lowering control valve Vd, the pressure port 22 communicates with the space between the control hole portion 21c and the plunger hole portion 21d. Further, the space between the contact portion 21b and the guide hole portion 21a communicates with the first drain port 23, and the space on the outer end side of the guide hole portion 21a (the space in which the descending side spring 26 is arranged) is the second. It communicates with the drain port 24. The first drain port 23 and the second drain port 24 individually communicate with the branch flow path 4.

Further, the second drain port 24 communicates with the guide hole portion 21a. The descent control pilot flow path 6 communicates with the outer end position of the plunger hole portion 21d.

The lowering control spool 25 is formed with a regulation wall portion 25a housed in the guide hole portion 21a, a contact land portion 25b abutting on the contact portion 21b, and a control land portion 25c housed in the control hole portion 21c. ing. Further, on the outer periphery of the control land portion 25c, an auxiliary flow path 25cg is formed in a groove shape in the direction of the lowering side plunger 25d from the intermediate position in the operating direction of the lowering control spool 25 to enable the flow of hydraulic oil. .. Further, a descending plunger 25d having the same diameter as the control land portion 25c is formed at a position connected to the control land portion 25c.

In this lowering control valve Vd, the lowering control spool 25 is maintained in the closed position shown in FIG. 6 by the contact land portion 25b coming into contact with the contact portion 21b by the urging force of the lowering side spring 26. In this closed position, the pressure port 22 is maintained in a closed state. The regulation wall portion 25a is also configured as a spring receiving member that receives the urging force of the descending spring 26.

Further, the dimensional relationship is set so that the outer circumference of the regulation wall portion 25a and the inner circumference of the guide hole portion 21a are close to each other. That is, the guide hole portion 21a has an inner peripheral surface of a cylinder centered on the second shaft core X2, and since the outer peripheral surface of the regulation wall portion 25a is close to this inner peripheral surface, there is a gap between them. It is small, and the phenomenon that the hydraulic oil from the pressure port 22 flows to the second drain port 24 when the lowering control spool 25 operates is suppressed.

When the descending solenoid valve Vdc is driven and the pilot pressure acts on the descending control pilot flow path 6, the descending control spool 25 operates to a position where the urging force of the descending spring 26 and the pilot pressure are balanced. The discharge position shown in 7 is reached.

In particular, the discharge position refers to a plurality of positions included in the region where the hydraulic oil flowing from the pressure port 22 into the lower spool chamber 21 flows to the first drain port 23, and among the discharge positions, the lower electromagnetic valve In the discharge position when the pilot pressure acting from the Vdc rises, the amount of hydraulic oil discharged increases as compared with the position where the pilot pressure is low.

As described above, when the contact land portion 25b is separated from the contact portion 21b and the pressure port 22 is separated from the contact land portion 21b at the discharge position shown in FIG. 7, the pressure port 22 is separated from the closed position via the auxiliary flow path 25cg of the control land portion 25c. The hydraulic oil from the above flows to the first drain port 23.

Further, when the lowering control spool 25 moves to the discharge position, the hydraulic oil in the space where the lowering side spring 26 is arranged is discharged from the second drain port 24 due to the displacement of the regulation wall portion 25a. In particular, when the lowering control spool 25 is set to the discharge position, the regulation wall portion 25a moves with the movement of the lowering side plunger 25d, but the regulation wall portion 25a is located inside the guide hole portion 21a. , The phenomenon that the hydraulic oil from the pressure port 22 flows to the second drain port 24 is suppressed.

When the drive current of the descending solenoid valve Vdc is increased, the operating amount of the descending control spool 25 also increases in accordance with the increase in the drive current. Therefore, when the lowering control spool 25 is in the discharge position, the amount of hydraulic oil discharged from the pressure port 22 to the first drain port 23 is increased in response to the increase in the drive current, and the lowering operation of the lift arm 1 is performed. Achieve high speed.

In particular, in this lowering control valve Vd, the contact land portion 25b has a relatively simple structure including the contact portion 21b, but the hydraulic oil from the pressure port 22 is discharged from the first drain port 23. It is possible to prevent the hydraulic oil from being trapped in the space (spring chamber) in which the descending spring 26 is arranged. As a result, even if the pressure of the hydraulic oil acting on the cylinder port Hc is high, the pressure in the space (spring chamber) in which the descending spring 26 is arranged rises (a muffled pressure is generated in the spring chamber) to close the through hole. It is possible to suppress the action of the directional force on the lowering control spool 25, and to reliably discharge the hydraulic oil even when the flow rate of the hydraulic oil is large.

[Solenoid valve]
In this valve unit A, a valve having a configuration common to the ascending solenoid valve Vuc and the descending solenoid valve Vdc is used. For this reason, common parts of the ascending solenoid valve Vuc and the descending solenoid valve Vdc will be described with a common reference numeral.

As shown in FIG. 8, the solenoid valve (a superordinate concept of the ascending solenoid valve Vuc and the descending solenoid valve Vdc) has a bottomed tubular first housing 31 made of a magnetic material and an opening of the first housing 31. A second housing 32 that is screwed and connected to the plunger body 33, a plunger body 33 made of a magnetic material housed inside the first housing 31, a coil portion 34 that creates magnetism acting on the plunger body 33, and a valve that controls the pilot pressure. It is configured to include a unit 35.

In this solenoid valve, the first housing 31 and the second housing 32 function as yokes that cause the magnetic flux from the coil portion 34 to act on the plunger body 33. The coil portion 34 has a structure in which a conducting wire made of a conductor is wound around the bobbin, and is configured to increase the magnetic force acting on the plunger body 33 as the current supplied to the conducting wire increases. ing.

In the first housing 31, an end wall 31b having a posture orthogonal to the third axis X3 is integrally formed at the outer end of the tubular wall 31a centered on the third axis X3, and the cylinder is as shown in FIG. A female screw portion 31S is formed on the inner circumference of the opening portion of the shaped wall 31a.

The second housing 32 sandwiches a shaft-shaped portion 32a housed in the internal space of the tubular wall 31a of the first housing 31, a large-diameter portion 32b having a larger diameter than the shaft-shaped portion 32a, and a large-diameter portion 32b. The shaft-shaped portion 32a and the protruding shaft portion 32c projecting to the opposite side are integrally formed. The solenoid valve is connected and fixed to the outer surface of the valve housing H with the protruding shaft portion 32c fitted in the hole portion of the valve housing H.

As shown in FIG. 9, a male screw portion 32S is formed on the outer periphery of the large diameter portion 32b of the second housing 32, and the male screw portion 32S is screwed into the female screw portion 31S of the first housing 31 to form a first. The housing 31 and the second housing 32 are connected to each other.

In the state where the second housing 32 is screwed and connected to the first housing 31 in this way, the center of the shaft-shaped portion 32a, the large diameter portion 32b, and the protruding shaft portion 32c of the second housing 32 is the third shaft core X3. Placed in matching positions. This screw connection structure will be described later.

The plunger body 33 is movably accommodated in the vicinity of the end wall 31b in the internal space of the first housing 31 in the direction along the third axis X3. An insertion hole 32d is formed in the shaft-shaped portion 32a of the second housing 32 with a coaxial core with the third shaft core X3. The plunger body 33 has a rod 33a that operates integrally, and the rod 33a is arranged in the insertion hole 32d in an inserted state.

In this solenoid valve (solenoid valve Vuc on the ascending side, solenoid valve Vdc on the descending side), the magnetic flux generated when the coil portion 34 is driven flows through the magnetic path formed in the first housing 31 and the second housing 32. When the magnetic path is formed in this way, the male threaded portion 32S and the female threaded portion 31S of the first housing 31 are screwed together on the outer periphery of the large diameter portion 32b of the second housing 32 to increase the magnetic resistance at the connecting portion. It has a structure that does not allow it.

As shown in FIG. 9, of the female threaded portions 31S formed in the first housing 31, the end portion on the protruding side of the male threaded portion 32S is screwed inward from the inner end position (right side in the figure). A pressure receiving surface 31T having a posture orthogonal to the third axis X3 is formed. Further, a contact surface 32T having a posture orthogonal to the third axis X3 is formed at the protruding end of the male screw portion 32S formed in the axial portion 32a of the second housing 32. The contact surface 32T is formed as a boundary wall having a posture orthogonal to the axis X at the boundary between the axial portion 32a and the large diameter portion 32b.

Further, of the female threaded portion 31S, an annular groove portion 31G is formed by removing the entire circumference of the inner end side portion where the protruding side end portion of the male threaded portion 32S is screwed in the direction along the third shaft core X3. .. The annular groove portion 31G is originally a region where an incomplete threaded portion is formed, and by forming the annular groove portion 31G in this way, it is appropriate when the male threaded portion 32S is screwed into the female threaded portion 31S. Achieves a smooth screw. By performing proper screwing in this way, the pressure receiving surface 31T and the contact surface 32T are securely brought into close contact with each other, and between the tubular wall 31a of the first housing 31 and the large diameter portion 32b of the second housing 32. The increase in the magnetic resistance of the magnetic path is suppressed.

The valve unit 35 slides the spool body 35a, which is operated in conjunction with the operation of the plunger body 33, and the spool body 35a, when the outer end portion of the rod 33a, which operates integrally with the plunger body 33, comes into contact with the valve unit 35. It is configured to include a control bush 35b for freely accommodating it.

The control bush 35b has a flow path in which hydraulic oil is supplied from the hydraulic oil supply port Hp and a flow path for discharging hydraulic oil to the discharge port Hd, and the spool body 35a is a pilot flow path (rising control pilot flow). The position where the pressure of the pilot flow paths 5 and 6 is greatly reduced by communicating the path 5 and the descending control pilot flow path 6) to the discharge port Hd, and the pressure of the hydraulic oil from the hydraulic oil supply port Hp are transferred to the pilot flow path 5 It is configured to be freely switchable to the position that acts on, and 6.

Further, by increasing the current for driving the solenoid valve (solenoid valve Vuc on the rising side, Vdc on the falling side) coil portion 34, it is possible to apply the pilot pressure corresponding to the current to the pilot flow paths 5 and 6. Become.

As a result, the pilot pressure of the ascending control pilot flow path 5 is increased by increasing the drive current of the ascending solenoid valve Vuc, and the ascending control spool 14 is greatly operated. As a result, the flow rate of the hydraulic oil supplied to the lift cylinder C is increased. Allows for growth.

Further, by increasing the drive current of the descending solenoid valve Vdc, the pilot pressure of the descending control pilot flow path 6 is increased, and as a result of operating the descending control spool 25 significantly, the amount of hydraulic oil discharged from the lift cylinder C is increased. Allows for an increase in.

[Action and effect of the embodiment]
In this configuration, when the ascending control spool 14 of the ascending control valve Vu reaches the supply position, the hydraulic oil from the pump port 12 is discharged through the plurality of communication holes 17 formed in the second land portion 14b. Although it will be supplied to the port 13, the communication hole will form a large opening for distribution on the outer peripheral surface of the second land portion 14b, so that a large amount of hydraulic oil can be supplied and each communication will be possible. Since the holes are formed in a posture orthogonal to the first shaft core X1, when the hydraulic oil flows through the communication holes, resistance does not act on the hydraulic oil, smooth flow is realized, and pressure loss is suppressed.

Although the descending solenoid valve Vdc has a relatively simple structure such that the contact land portion 25b of the descending control spool 25 is brought into contact with the contact portion 21b to prevent the flow of hydraulic oil, the descending solenoid valve Vdc is configured from the pressure port 22. The regulated wall portion 25a for suppressing the inconvenience of flowing the hydraulic oil of the above to the second drain port 24 is provided. Therefore, for example, as compared with a control valve having a configuration in which hydraulic oil from the pressure port 22 is discharged through a space (spring chamber) in which a descending spring 26 is arranged, the muffled pressure of the spring chamber is lowered control spool 25. It is possible to eliminate the inconvenience that the flow rate of the hydraulic oil is lowered due to the action.

The ascending solenoid valve Vuc and the descending solenoid valve Vdc have a common configuration, and in each solenoid valve, a first housing 31 made of a magnetic material and a second housing 32 made of a magnetic material are screwed and connected. It is configured to be integrated by.

In particular, in this solenoid valve, the male screw portion 32S formed on the outer circumference of the large diameter portion 32b of the second housing 32 with respect to the female screw portion 31S on the inner circumference of the opening portion of the tubular wall 31a of the first housing 31. It is a configuration to screw. In this structure, by forming the annular groove portion 31G from which the entire circumference of the inner end side portion of the female screw portion 31S is removed, the pressure receiving surface 31T of the first housing 31 and the contact surface 32T of the second housing 32 are reliably secured. The increase in magnetic resistance at this site is suppressed.

[Another Embodiment]
The present invention may be configured as follows in addition to the above-described embodiments (those having the same functions as those of the embodiments are designated by the same numbers and reference numerals as those of the embodiments).

(A) In the embodiment, the contact land portion 25b is brought into contact with the contact portion 21b of the lowering side spool chamber 21 to maintain the lowering control spool 25 in the closed position and prevent the flow of hydraulic oil. Instead of this, by bringing a part of the control land portion 25c into contact with the end portion of the control hole portion 21c of the descending side spool chamber 21, the descending control spool 25 is maintained in the closed position and the flow of hydraulic oil is prevented. Configure to block.

In addition, as the configuration of the descending control valve Vd (control valve) having the configuration of the other embodiment (a), a cylindrical and smooth outer surface centered on the second shaft core X2 is formed instead of the contact land portion 25b. It is also possible to form the inner surface of the contact portion 21b in the shape of a cylindrical inner surface so that the land portion is provided and the land portion can be inserted.

Even with such a configuration, when the lowering control spool 25 is set to the discharge position, the regulation wall portion 25a can prevent the flow of hydraulic oil to the second drain port 24.

(B) The lowering control valve Vd (control valve) is not limited to the one operated by the pilot pressure, but is operated to the discharge position by the operating force from the electromagnetic solenoid or the mechanical operating force from the outside. It is also possible to apply it to things.

The present invention can be used for a control valve that supplies and discharges hydraulic oil by operating a spool.

21 Downward spool chamber (spool chamber)
21a Guide hole 22 Pressure port 23 1st drain port 24 2nd drain port 25 Lowering control spool (spool)
25a Regulatory wall 25d Downward side plunger (plunger)
26 Downward spring (spring)
H Valve housing X2 2nd shaft core (working shaft core)

Claims (4)

A spool chamber is formed by the working shaft core and the coaxial core, and the pressure port on which the pressure of the hydraulic oil acts, the first drain port for discharging the hydraulic oil, and the second drain port for discharging the hydraulic oil are in this order. A valve housing arranged along the working shaft core and having these ports communicating with the spool chamber.
A closed position that is housed in the spool chamber and closes the pressure port, and a discharge that discharges hydraulic oil that flows into the spool chamber from the pressure port from the spool chamber to the first drain port by opening the pressure port. With a spool that can be operated freely in the position,
A spring is provided in the spool chamber, which is accommodated in a portion where the second drain port communicates, and which urges the spool from the side of the discharge position to the side of the closed position.
In the spool, the control land portion, the contact land portion, and the regulation wall portion are formed in this order along the operating axis, and when the spool is in the closed position, the control land portion and the regulation wall portion are formed. The contact land portion blocks the flow of hydraulic oil from the pressure port to the first drain port, and the control land portion and the contact land portion are opened when the spool is in the discharge position. The hydraulic oil from the pressure port is discharged from the space between the control land portion and the contact land portion to the first drain port.
The restricting wall suppresses the flow of hydraulic oil from the pressure port to the second drain port regardless of whether the spool is in the closed position or the discharged position .
A control valve in which the regulation wall portion is configured as a spring receiving member that abuts on the spring and receives the urging force of the spring . The control valve according to claim 1, wherein the spool chamber has a guide hole portion which is an inner peripheral surface close to the outer periphery of the regulation wall portion in a region where the spool moves from the closed position to the discharge position. .. The control valve according to claim 1 or 2, wherein the spool has a solid structure . The spool has a structure in which a plunger is integrally formed at an end opposite to the position where the spring is arranged, and the spool is placed between the closed position and the discharged position by controlling the pressure acting on the plunger. The control valve according to any one of claims 1 to 3, which is configured to be freely operable.

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