JP2514159Y2 - Flow control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a pressure oil flow rate control valve for controlling the drive direction and drive speed of a hydraulic drive actuator used in, for example, construction equipment.

[Conventional technology]

Generally, a conventional flow rate adjusting valve of this type is composed of a spool valve portion 12 and a pressure compensating portion 14 which are arranged in parallel in a valve body 10 as shown in FIG. And
An oil hole 18 composed of a first variable throttle and an oil hole 20 composed of a second variable throttle are opened in the wall portion of the spool 16 of the spool valve portion 12, while the pressure compensating portion 14 regulates pressure. spring
22 and a pressure compensating spool 24 are provided. In addition,
In the figure, reference numeral P indicates a pressure oil supply core, CA and CB indicate cylinder cores, TA and TB indicate return oil cores, and reference numeral 26 is slidably arranged in the hollow portion of the spool 16. Check valve. Therefore, according to such a flow rate adjusting valve, when the spool 16 is operated from the outside by, for example, moving to the right side in the drawing, the oil discharged from the pump is
Core P → first variable aperture 18 → second variable aperture 20 → core CA
→ actuator cylinder (not shown) → core CB → first
Of the variable throttle 18 → second variable throttle 20 → core TB to the tank (not shown). However, in this case, the first
Since the differential pressure before and after the variable throttle 18 is always kept constant via the pressure compensator 14, the supply flow rate to the actuator is irrespective of the pressure in the core CA, that is, the load pressure of the actuator. It is set to a constant flow rate determined by the opening area of the first variable aperture 18 corresponding to the movement amount. In this case, the load pressure of the actuator (core CA
When the internal pressure) becomes higher than the pump discharge pressure (the internal pressure of the core P), the check valve 26 operates to close the flow passage in the hollow portion of the spool 16. Therefore, the reverse flow of the pressure oil is blocked and the so-called load holding action is achieved.

As described above, the conventional flow rate adjusting valve of this type has a spool valve portion as a variable throttle portion that sets the flow area of pressure oil,
Since the load compensation function is added to the spool valve section, it is equipped with a pressure compensation section as a pressure control section that maintains a constant differential pressure across the variable throttle section. The load holding action can be achieved at the same time as well as at any speed.

[Problems to be solved by the device]

However, in the conventional flow rate adjusting valve of this type, as described above, the spool valve portion as the variable throttle portion and the pressure compensating portion as the pressure control portion are separately configured. Therefore, the structure of the valve body is inevitably complicated and at the same time large in size.

Therefore, an object of the present invention is to provide a flow rate adjusting valve that can arbitrarily set the flow rate supplied to the actuator regardless of the load pressure of the actuator, has a load holding function, and has a simple structure and can be configured in a small size. To do.

[Means for solving the problem]

In order to achieve the above object, a flow control valve according to the present invention comprises a valve body (10) and a hollow valve spool (slidably provided in the valve body, which moves in accordance with an operation amount from the outside. 30), in the housing of the valve body, a pressure oil supply core (P) is provided at the center of the valve spool in the axial direction, and return oil cores (TA, T are provided at both end portions).
B) and a core (CA, CB) for a cylinder that communicates with a hydraulic drive actuator are provided between the core and the wall of the valve spool, and when the operation amount is in the neutral state of zero, the pressure oil is When moving the valve spool (30) between the supply core (P) and the cylinder core (CA, CB) and between the cylinder core (CA, CB) and the return oil core (TA, TB) An oil hole consisting of a first variable aperture (18) whose opening area changes according to the amount of movement and a second variable aperture (2)
0) In the flow rate control valve formed by opening each oil hole, one end is in the end spring chamber (42) of the hollow part of the valve spool (30) and the other end is the hollow part of the valve spool (30). The oil passages are constructed by the pressure compensating pistons (46) respectively arranged in the central flow passage chamber (44) of this section, and the auxiliary spool (48) is slidably incorporated inside the pressure compensating pistons (46). A pressure adjusting spring (54) is provided in an oil chamber (52) communicating with the flow path chamber (44) via a (50), and a spring (56) is further provided in the spring chamber (42) to provide the pressure compensating piston. By loading against (46),
It is characterized in that a pressure compensating means (40) is provided which operates as a pressure section and at the same time has a load holding function.

In this case, the pressure compensation means (40) is the auxiliary spool (4
8) The pressure compensating piston (46) moves according to the set pressure of the pressure adjusting spring (54) by the pressure reducing action in the spring chamber (42), and controls the opening area of the second variable throttle (20). At the same time, the upstream pressure of the first variable throttle (18) becomes higher than that of the oil passage (3
4), core (L), oil spool (32) through auxiliary spool (4
8) is configured to act on the other side surface to appropriately reduce the pressure in the spring chamber (42) by the auxiliary spool (48), and further the pressure compensating piston (46) to the second variable throttle (46). It can be configured to move to the closed position of 20).

[Action]

The pressure compensating means as the pressure control section is incorporated in the hollow portion of the valve spool constituting the spool valve section as the variable throttle, and the pressure compensating means is provided with a load holding function. Therefore, the structure of the valve body is significantly smaller and simpler than the conventional flow rate adjusting valve of this type.

〔Example〕

Next, an embodiment of the flow control valve according to the present invention will be described in detail below with reference to the accompanying drawings. For convenience of explanation, the same components as those of the conventional flow rate adjusting valve shown in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

First, the structure of the valve housing and the valve spool of the present invention is basically the same as the structure of the spool valve portion in the conventional flow rate adjusting valve. That is, in FIG. 1, the spool valve is a valve body 10 and a hollow valve spool 30 slidably provided in the valve body 10.
Consists of And, in the housing of the valve body 10,
A pressure oil supply core P is provided at the center of the valve spool 30 in the axial direction, return oil cores TA and TB (may be simply referred to as core T) for returning to the tank at both end portions, and between the two cores. Cylinder cores CA and CB (may be simply referred to as core C) communicating with a hydraulic drive actuator (not shown) are provided respectively. On the other hand, in the wall portion of the valve spool 30, at the neutral position of the valve spool 30, an oil hole 18 made of a first variable throttle is opened between the cores P and C, and between the cores C and T. An oil hole 20 composed of a second variable diaphragm is opened in the.

However, in the flow control valve of the present invention, the pressure compensating means 40 is slidably provided in the hollow portion of the valve spool 30. The valve housing is provided with cores L and M outside the core T, and the valve spool 30 has cores L and M.
A communication oil hole 32 is provided at a position corresponding to, the core L, P,
L is communicatively connected via an oil passage 34, and cores M, T, L are communicatively connected via an oil passage 36.

The pressure compensating means 40 is composed of a pressure compensating piston 46, one end of which is arranged in the end spring chamber 42 of the hollow portion of the valve spool and the other end of which is arranged in the central flow passage chamber 44 of the hollow portion of the valve spool. It An auxiliary spool 48 is slidably incorporated in the pressure compensating piston 46, and a pressure adjusting spring 54 is provided in an oil chamber 52 communicating with the flow path chamber 44 via an oil passage 50. The spring chamber
A spring 56 is provided at 42 and is loaded against the pressure compensating piston 46. Thereby, the pressure compensation means 40
Is configured to act as a pressure controller and at the same time achieve a load holding function, as will be apparent from its operation described later.

Next, the operation of the flow control valve of the present invention having such a configuration will be described. First, in the state shown in FIG. 1, when a spool switching signal of an arbitrary size is applied to the a side, the spool 30 moves to the right side in the drawing by a lift amount 1 corresponding to the size of the signal, and the flow rate is adjusted. In the valve, a flow path is formed that flows from the left side to the right side in the figure. The state at this time is shown in FIG. 2. First, the inflow side (left side in the figure) will be described. Due to the movement, the first and second variable throttles 18, 20 are respectively lifted by the lift amount l. The cores P and CA are opened by an amount commensurate with The aperture of the second variable aperture 20 is set to be sufficiently larger than the aperture of the first variable aperture 18. Then, due to the opening, the pressure oil from the core P passes through the first variable throttle 18 and enters the in-spool flow passage chamber 44 to push down the pressure compensating piston 46 as shown in the drawing, and the second variable throttle 20. Flow through the core CA, and the oil pressure in the flow passage chamber 44, that is, the downstream pressure of the first variable throttle 18, acts on the front surface of the pressure compensating piston 46, and the oil passage 50, the oil chamber The pressure adjusting spring 54 of the auxiliary spool 48 acts on the end face of the auxiliary spool 48 via 52. Meanwhile, at the same time, the oil pressure in the core P, that is, the first
The upstream side pressure of the variable throttle 18 of the oil passage 34, the core L, the oil hole
It acts on the other end surface of the auxiliary spool 48 via 32. Therefore, as a result, the pressure in the spring chamber 42 is appropriately reduced by the auxiliary spool 48, so that the pressure compensating piston
46 indicates that the downstream pressure of the first variable throttle 18 acting on the front surface of the first variable throttle 18 is the same as the upstream pressure of the first variable throttle 18.
The second variable aperture 20 is moved to the aperture adjustment position such that the pressure difference set by the pressure adjusting spring 54 decreases. That is, the flow rate passing through the first variable restrictor 18 is set to a flow rate determined according to the differential pressure set by the pressure adjusting spring 54 regardless of the pressure in the core CA, that is, the load pressure of the actuator. Then, this supply flow rate is discharged to the tank (not shown) via the core CA → actuator (not shown) → core CB → flow channel chamber 44 → core TB. In this case, the supplied pressure oil is the core CB → the flow passage chamber.
44 → Pressing down the pressure compensating piston 46 when passing through the core TB, but at this time, the pressure inside the spring chamber 42 becomes equal to the pressure inside the core TB via the oil hole 32, the core M, and the oil passage 36. The pressure compensating piston 46 (on the right side in the figure) on the outflow side does not have a pressure control function, that is, an opening area adjustment function of the second variable throttle 20.

Next, the load holding function of the pressure compensating means 40 according to the present invention will be described. That is, in the above operation, when the load pressure of the actuator, that is, the pressure in the core CA becomes higher than the pressure of the supply pressure oil, that is, the pressure in the core CA, in the pressure compensating means 40 of the present invention, the auxiliary spool 48
Is set to the state left switched in the figure.
As a result, the pressure in the core P is conducted into the spring chamber 42 via the oil passage 34 and the oil hole 32, whereby the pressure compensating piston 46 is pushed up to the right in the figure, and the second variable throttle 20 is closed. It Therefore, backflow of the pressure oil from the core CA to the core P is prevented. That is, the function of holding the actuator load is achieved.

As described above, according to the flow rate adjusting valve of the present invention, since the pressure adjusting means having a load holding function is incorporated in the spool valve, the structure of the valve body is changed to the conventional flow rate adjusting valve of this type. In comparison, the size and size can be greatly reduced.

FIG. 3 shows another embodiment of the flow rate adjusting valve according to the present invention. In this embodiment, the pressure compensation function is changed from the inflow side to the outflow side with respect to the actuator in the previous embodiment. That is, in the present embodiment, the cores C and M are connected via the oil passage 60, and when a spool switching signal is applied to the side a, for example, as in the previous embodiment, the spool 30 Is moved to the right side in the figure, and the supply pressure oil is core P → flow path chamber 44 → core CA → actuator → core
The pressure compensating piston 46 on the outflow side (on the right side in the figure) is set to the set differential pressure of the pressure adjusting spring 54 by the action of the auxiliary spool 48 while flowing out to the tank through CB → flow path chamber 44 → core TB. By correspondingly moving, the opening area of the second variable diaphragm 20 is adjusted to keep the differential pressure across the first variable diaphragm 18 constant. The load holding function is performed by the pressure compensating means 40 on the inflow side (left side in the figure). It will be apparent that the same effect as in the previous embodiment is exerted in this embodiment as well.

The preferred embodiments of the flow control valve of the present invention have been described above, but the present invention is not limited to these embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. .

[Effect of device]

As described above, the flow control valve according to the present invention includes a valve body (10) and a hollow valve spool (30) slidably provided in the valve body and moving according to an operation amount from the outside. In the housing of the valve body, a pressure oil supply core (P) is provided at the center in the axial direction of the valve spool, return oil cores (TA, TB) are provided at both ends, and hydraulic drive is provided between the cores. A cylinder core (CA, CB) communicating with the actuator is provided, and the pressure oil supply core (P) and the cylinder core (P) are provided for the wall portion of the valve spool when the manipulated variable is in a neutral state. CA, CB) and cylinder core (CA, CB) and return oil core (T
A, TB), the first variable aperture (1) that changes the opening area according to the amount of movement of the valve spool (30) during movement.
8) and a second variable restrictor (20) having an oil hole opened therein. In the flow rate adjusting valve, one end is in the end spring chamber (42) of the hollow part of the valve spool (30). In addition, the other end is configured with a pressure compensating piston (46) arranged in the central flow passage chamber (44) of the hollow portion of the valve spool (30), and is assisted inside the pressure compensating piston (46). A spool (48) is slidably incorporated, and a pressure adjusting spring (54) is provided in an oil chamber (52) communicating with the flow path chamber (44) via an oil passage (50), and the spring chamber (42) is further provided. ) Is provided with a spring (56) to apply a load to the pressure compensating piston (46), thereby providing a pressure compensating means (40) configured to operate as a pressure section and simultaneously have a load holding function. The spool valve section and pressure compensation section. Compared to a separate configured once was a conventional flow regulating valve of this kind, the structure of the valve body can be downsized to and simplified considerably.
In particular, in the present invention, since the pressure compensating means has a load holding function, the load holding of the actuator can be easily and surely achieved without changing the structure of the valve body.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a flow rate control valve according to the present invention, and FIG. 2 is a sectional view showing a state when the valve spool of the flow rate control valve shown in FIG. 1 is moved to the right side in the figure. ,
FIG. 3 is a sectional view showing another embodiment of the flow rate control valve according to the present invention, and FIG. 4 is a sectional view showing a conventional flow rate control valve. 10 …… Valve body 18 …… First variable throttle (oil hole) 20 …… Second variable throttle (oil hole) 30 …… Valve spool, 32 …… Oil hole 34,36 …… Oil passage, 40 ...... Pressure compensator 42 …… Spring chamber, 44 …… Flow passage chamber 46 …… Pressure compensating piston 48 …… Auxiliary spool, 50 …… Oil passage 52 …… Oil chamber, 54 …… Pressure adjusting spring 56 …… Spring , 60 …… Oil passage P …… Pressure oil supply core CA, CB …… Cylinder core TA, TB …… Return oil core l …… Lift amount

Claims (2)

(57) [Scope of utility model registration request] 1. A valve body (10), and a hollow valve spool (30) slidably provided in the valve body and moving according to an operation amount from the outside. Is a pressure oil supply core (P) at the central portion in the axial direction of the valve spool, return oil cores (TA, TB) at both end portions, and a cylinder core (CA) that communicates with the hydraulic actuator between the cores. , CB), and between the pressure oil supply core (P) and the cylinder core (CA, CB) and the cylinder when the manipulated variable is zero with respect to the wall of the valve spool. For core (CA, C
Between the return oil core (TA) and the return oil core (TA), the oil hole including the first variable throttle (18) that changes the opening area according to the movement amount of the valve spool (30) and the first In the flow rate adjusting valve formed by opening the oil holes composed of the two variable throttles (20), one end is in the end spring chamber (42) of the hollow part of the valve spool (30) and the other end is the valve spool. The pressure compensating piston (46) is arranged in the central flow passage chamber (44) of the hollow part of (30), and the auxiliary spool (48) is slidable inside the pressure compensating piston (46). And a pressure adjusting spring (54) provided in the oil chamber (52) communicating with the flow passage chamber (44) through the oil passage (50), and a spring (56) provided in the spring chamber (42). Acting as a pressure part by applying a load to the pressure compensating piston (46) That the flow rate control valve, characterized in that at the same time providing a configuration with pressure compensation means (40) so as to have a load holding function. 2. The pressure compensating means (40) includes an auxiliary spool (4).
8) The pressure compensating piston (46) moves according to the set pressure of the pressure adjusting spring (54) by the pressure reducing action in the spring chamber (42), and controls the opening area of the second variable throttle (20). At the same time, the upstream pressure of the first variable throttle (18) becomes higher than that of the oil passage (3
4), core (L), oil spool (32) through auxiliary spool (4
8) is configured to act on the other side surface to appropriately reduce the pressure in the spring chamber (42) by the auxiliary spool (48), and further the pressure compensating piston (46) to the second variable throttle (46). The flow rate adjusting valve according to claim 1, wherein the flow rate adjusting valve is configured to be operated to the closed position of 20).