JPH08303408A - Pressure reducing valve pilot valve device - Google Patents

Abstract

(57) [Summary] [Object] To provide a pressure reducing valve type pilot valve device capable of including a high pressure selecting structure for guiding the pressure of an output port to a signal port in one plane area. [Structure] Spools 40, 40 'for communicating the output ports 7, 7'with the pump port 3 or the tank port 5, pushers 15, 15', and a setting spring for setting the pressure on the output ports 7, 7'side A small diameter portion 40E formed on the spool 40, 40 ',
40E 'and the selection channel 4 for selectively communicating the output ports 7, 7'and the communication channels 42A, 42A' through the small diameter portions 40E, 40E 'with the movement of the pushers 15, 15'.
3, 43 ', and one high pressure selecting means having a ball 45, which is interposed between the communication channels 42A, 42A' and the signal port 46, and the spools 40, 40 '.
At the same time, throttles 47 and 47 'for communicating the signal port 46 with the tank port 5 are always provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in a hydraulic machine such as a hydraulic excavator and has a directional control valve in a main circuit and a pilot valve for supplying pilot pressure for controlling a tilt control section of a pump in a casing. The present invention relates to a pressure reducing valve type pilot valve device provided with four pressure reducing valve type pilot valve devices.

[0002]

4 to 7 are explanatory views showing a conventional pressure reducing valve type pilot valve device of this type. FIG. 4 is a circuit diagram showing a hydraulic circuit including the pressure reducing valve type pilot valve device, and FIG. Figure 4
6 is a sectional view taken along the arrow B of FIG. 6, FIG. 6 is a sectional view taken along the arrow C of FIG. 4, and FIG. 7 is a diagram showing the pressure reducing valve type pilot valve device shown in FIG.

4 to 7, and particularly FIG. 4, reference numeral 1 denotes a casing which constitutes the main body of the pressure reducing valve type pilot valve device. Inside this casing 1, a hydraulic pump 2 serving as a pilot hydraulic pressure source is provided as a common port. A pump port 3 into which pressure oil from the tank flows in, a tank port 5 that is in constant communication with the tank 4, and a signal port 23 that supplies a pressure signal to the outside are provided.

The casing 1 is provided with four pressure reducing valve type pilot valves 50A, 51A, 52A, 53A. In FIG. 4, two pilot valves 50A, 51A are provided.
Only shown. Where the two pilot valves 50
The corresponding one of A and 51A, that is, the constituent member of the pilot valve 50A is not marked with "", and the constituent member of the pilot valve 51A is marked with "".
The code without the “′” and the code with the corresponding “′” have almost the same configurations. Therefore, in the following, in order to simplify the description, the description will be made mainly by using the reference numerals without "'".

The pilot valve 50A is in constant communication with the above-mentioned tank port 5 and has a spring chamber 6 having a stepped portion 6A, an output port 7 provided in the vicinity of the spring chamber 6 and formed in a substantially L shape. A pressure chamber 8 that is in constant communication with the output port 7 and that applies a pressure inside the output port 7 is provided on the end surface of the spool 12 on the lower end side, which will be described later.

Further, a flow passage 9 is formed between the tank port 5 and the output port 7, and a flow passage 10 is formed between the output port 7 and the pump port 3, and these flow passages 9, The spool 10 is selectively opened and closed by a spool 12. And the output port 7 of this pilot valve 50A,
The output port 7'of the pilot valve 51A is connected to the hydraulic pilot portion 11 of the directional control valve 11 provided in the middle of the main circuit.
The pressure in the output ports 7 and 7'is applied to A and 11B, and thereby the switching control of the directional switching valve 11 is performed.

The spool 12 of the pilot valve 50A described above
Slides in the flow path 10 to connect and disconnect the output port 7 and the pump port 3, and the end face on the lower end side is the pressure chamber 8
Large-diameter portion 12A facing the large-diameter portion 12A, and a small-diameter portion 12 extending upward from the large-diameter portion 12A and extending into the spring chamber 6
B, and a head 12C provided on the upper end of the small diameter portion 12B
And an annular portion 12D which is provided in the middle portion of the small diameter portion 12B at a predetermined distance from the large diameter portion 12A and which slides in the flow passage 9 to communicate and block the tank port 5 and the output port 7. It is configured. And this spool 1
A large diameter portion 12A and an annular portion 12D 2 selectively connect the output port 7 to either the pump port 3 or the tank port 5.

Reference numeral 13 denotes the casing 1 on the upper end side of the spring chamber 6.
The bushing 15 is fitted into the bushing and is prevented from coming off by the upper lid 14, and the pusher 15 is slidably inserted into the bushing 13 and has a tip side projecting upward from the bushing 13. It engages with the lower end side of 13 and is prevented from coming off from this bushing 13. A circular recess 15A is formed in the center of the pusher 15 on the base end side, and the head 12C of the spool 12 is inserted into the recess 15A so as to be relatively displaceable. The pusher 15 is pushed in the axial direction by an operating rod 18 described later, and at this time, the spool 12 is slid in the axial direction via a setting spring 17 described later.

Reference numeral 16 denotes a return spring for returning the pusher 15 to the initial position (neutral position) shown in FIG. 4, and the return spring 16 is arranged in the spring chamber 6 and moves the pusher 15 upward in the axial direction. Always urged. Where pusher 1
When 5 is pressed largely in the axial direction, the maximum stroke is regulated by the stepped portion 6A of the spring chamber 6, and the proximal end side of the pusher 15 engages with the lower end side of the bushing 13 at the initial position shown in the drawing, so that It is held in a retaining state via 13.

Reference numeral 17 denotes a setting spring which is interposed between the pusher 15 and the spool 12 and which sets the pressure by the spool 12 in accordance with the push operation amount of the pusher 15, and the setting spring 17 is inside the spring chamber 6. It is located inside the return spring 16 and is arranged between the pusher 15 and the annular portion 12D of the spool 12 with a predetermined preset load. The setting spring 17 allows the spool 12 to slide axially downward when the pusher 15 is pressed.

Here, in the setting spring 17, as the spool 12 slides, the annular portion 12D closes the flow passage 9, and the large diameter portion 12
When A opens the flow path 10 and the pressure in the output port 7 (pressure chamber 8) acts on the lower end side end surface of the spool 12, the spool 12 is allowed to slide axially upward, and the annular portion 12D The flow paths 9 and 10 are opened and closed by the large diameter portion 12A. Then, the setting spring 17 causes the pressure chamber 8
Since it is bent by the internal pressure, the spool 12 is slid up and down while the spring load at that time and the pressure in the pressure chamber 8 are balanced, and the pressure in the output port 7 is set appropriately. There is.

The above construction is the same for the other pilot valve 51A whose corresponding reference numeral is indicated by "'" and another pair of pilot valves 52A, 53A not shown.

Reference numeral 18 denotes an operating rod for pressing the pusher 15. The operating rod 18 swings in the directions of arrows A and B via a pin 20 to a mounting member 19 projecting upward from the central portion of the upper end side of the casing 1. It is movably mounted. The operating rod 18 is formed in a substantially T shape, the lower end surface side of which is slightly inclined, and the pusher 1 of the pilot valve 50A is provided.
5, the pressing portions 18A and 18A 'against the pusher 15' of the pilot valve 51A. That is, the operating rod 18 is a pair of pilot valves 50A and 51A shown in FIG.
Used for the operation of. Note that another operating rod (not shown) is provided for operating the other pair of pilot valves 52A and 53A not shown in FIG.

Inside the casing 1, there is a pilot valve 50A.
7A communicating with the output port 7 of the pilot valve 5
A flow path 7A 'communicating with the output port 7'of 1A is provided, and these flow paths 7A and 7A' are selectively connected to the flow path 33 shown in FIG. . That is, the ball 24 and the sleeve 25 seated by the contact of the ball 24 are arranged in the flow path 7A ′, and the blind plug 26 is provided at the end of the sleeve 25.
When the flow path 7A has a higher pressure than the flow path 7A ', the ball 2
When 4 is brought into contact with the sleeve 25, the flow passage 7A communicates with the flow passage 33, and the flow passage 7A ′ has a higher pressure than the flow passage 7A,
The flow path 7A is closed by the ball 24, and the flow path 7A '
Communicate with the flow path 33. That is, the ball 24 and the sleeve 25 constitute a first high pressure selecting means for selectively extracting high pressure.

The same applies to the other pair of pilot valves 52A and 53A, and as shown in FIG.
7B communicating with the output port of the pilot valve 53
A flow path 7B 'communicating with the output port of A is provided, and these flow paths 7B and 7B' are the flow path 33 shown in FIG.
It is configured so as to selectively communicate with the ‘ That is, the ball 24 'and the ball 24' in the flow path 7B '.
And a sleeve 25 'which is seated by the contact between the sleeve 25' and the blind plug 26 'are provided at the end of the sleeve 25'. When the flow path 7B has a higher pressure than the flow path 7B ', the ball 24' is brought into contact with the sleeve 25 ', the flow path 7B communicates with the flow path 33', and the flow path 7B 'is compared with the flow path 7B. When the pressure is high, the flow path 7B is closed by the ball 24 ', and the flow path 7B' communicates with the flow path 33 '. That is, the ball 24 'and the sleeve 25' constitute a second high pressure selecting means for selectively extracting high pressure.

Further, in the plane area below the plane area in which the above-mentioned first high pressure selecting means and second high pressure selecting means are arranged in the casing 1, the above-mentioned flow paths 33, 3 are provided.
Third high voltage selecting means for selectively communicating one of the 3'with the signal port 23 is provided. That is, the ball 32 and the sleeve 31 which constitute the third high pressure selecting means are arranged on the side of the flow path 33 ', and the blind plug 34 is provided at the end of the sleeve 31. Flow path 3 described above
When the pressure of 3 is higher than that of the flow passage 33 ′, the ball 32 is brought into contact with the sleeve 31 and the flow passage 33 communicates with the signal port 23. , The ball 32 closes the flow path 33, and the flow path 33 ′ communicates with the signal port 23. Pilot valve 50 described above
The relationship between A, 51A, 52A and 53A and the first, second and third high voltage selecting means is summarized as shown in FIG.

21A and 21B shown in FIG. 4, the output port 7 of the pilot valve 50A and the output port 7'of the pilot valve 51A are connected to the hydraulic pilot portion 1 of the direction switching valve 11.
Pilot lines connected to 1A and 11B respectively, 2
Reference numeral 2 is a relief valve for setting the pressure of the pressure oil output from the hydraulic pump 2 to a predetermined pressure. Further, 29 is a main circuit hydraulic pump, and 29 A is a tilt control unit of the hydraulic pump 29, which is controlled by a signal from the signal port 23 via the signal passage 27. 28 is a prime mover that drives the hydraulic pumps 2 and 29, and 30 is an actuator controlled by the direction switching valve 11. Although not shown, another pair of pilot valves 52A and 53A also drives the directional control valve that controls another actuator via the pilot conduit.

The operation of the prior art thus configured is as follows. In addition, in the following, FIG.
The operation of the pair of pilot valves 50A and 51A shown in FIG. 4 will be described, but the operation of another pair of pilot valves 52A and 53A not shown in FIG. 4 is basically the same.

As shown in FIG. 4, for example, when the operating rod 18 is in the initial position (neutral position), the large diameter portion 12A of the spool 12 closes the flow passage 10 and the annular portion 12D opens the flow passage 9, The output port 7 communicates with the tank port 5 via the flow path 9, while being blocked from the pump port 3 and placed in a low pressure state. The same applies to the spool 12 ', and the output port 7'is also placed in a low pressure state. As a result, each hydraulic pilot portion 1 of the direction switching valve 11
1A and 11B become equal pressure, and the direction switching valve 11 is held at the neutral position (a) as shown in the figure.

Therefore, when the operating rod 18 is tilted in the direction of arrow A, the pusher 15 is pushed downward in the axial direction by the pushing portion 18A, and the spool 12 passes through the setting spring 17 according to the amount of manipulation at this time. Slides downward in the axial direction. The annular portion 12D of the spool 12 is connected to the flow path 9
When the large-diameter portion 12A opens the flow path 10 while closing, the output port 7 is blocked from the tank port 5 and communicates with the pump port 3. As a result, the pressure in the output port 7 and the pressure chamber 8 becomes high, and the pressure in the pressure chamber 8 acts on the spool 12 as a feedback pressure to push the spool 12 upward in the axial direction. The setting spring 17 is compressed and bent from the preset state.

When the annular portion 12D of the spool 12 opens the flow passage 9 again, the output port 7 communicates with the tank port 5, and the large diameter portion 12A closes the flow passage 10.
Since the pressures in the output port 7 and the pressure chamber 8 drop,
Due to the spring load of the setting spring 17, the spool 12 slides axially downward again, the setting spring 17 returns to the preset state, and the large diameter portion 12A of the spool 12 opens the flow path 10 again. As a result, the pressure inside the output port 7 and the pressure chamber 8 rises.

Thus, the spool 12 repeatedly slides up and down in the axial direction, and when the pusher 15 presses a small amount, the pilot pressure corresponding to the preset load of the setting spring 17 is output from the output port 7 to the pilot pipe. It is supplied to the hydraulic pilot portion 11A of the direction switching valve 11 via the passage 21A.

Next, when the operating rod 18 is further swung in the direction of the arrow A to increase the pushing operation amount of the pusher 15, the setting spring 17 has a force equal to or greater than the preset load.
Is slid downward in the axial direction, and the spool 12 keeps opening and closing the flow passages 9 and 10 and keeps the output port 7 in a pressure state corresponding to the spring load (deflection amount) of the setting spring 17. Set the pressure of.

That is, a spring load corresponding to the pressing operation amount of the pusher 15 is generated in the setting spring 17, and the pressure in the output port 7 is controlled according to this spring load. Then, the direction switching valve 11 is switched from the neutral position (a) to the left switching position (b) with a stroke amount corresponding to the pressure (pilot pressure) in the output port 7.

When the pushing operation amount of the pusher 15 is further increased, the head portion 12C of the spool 12 comes into contact with the upper surface of the recess 15A of the pusher 15, and the setting spring 17 is bent further. Instead, the spool 12 slides axially downward together with the pusher 15.
As a result, regardless of the pressure in the pressure chamber 8, the output port 7
Is maintained in communication with the pump port 3, and the pressure in the output port 7 is equal to the pressure in the pump port 3 (that is, the pressure oil pressure from the hydraulic pump 2 set by the relief valve 22). Be put in a state. Then, the direction switching valve 11 is completely switched to the left switching position (b) by this pressure.

Thus, the pusher 1 by the operating rod 18
The pressure in the output port 7 is set until the head 12C of the spool 12 contacts the upper surface of the recess 15A of the pusher 15 while the setting spring 17 is gradually compressed from the preset state in accordance with the pressing operation of 5. The pressure is controlled to be reduced to a value corresponding to the spring load of the working spring 17, and the directional switching valve 11 can be gradually switched from the neutral position (a) to the switching position (b) by the pressure in the output port 7. . Then, by controlling the switching from the neutral position (a) to the switching position (b) of the direction switching valve 11, the amount of pressure oil flowing into the main circuit via the direction switching valve 11 is gradually changed from a small flow rate to a large flow rate. And the flow rate can be controlled.

When the pressure corresponding to the operation amount of the operating rod 18 is generated by the pressure reducing action of the pilot valve 50A including the spool 12 as described above, the flow passage 7A connected to the output port 7 is generated.
Becomes the same pressure.

Here, the flow path 7A 'of the pilot valve 51A
Communicates with the tank port 5 via the output port 7'and the flow path 9 ', the ball 24 constituting the first high pressure selecting means moves rightward in FIG. It abuts the seat portion of the sleeve 25, and the pilot valve 5
The communication between the flow passage 7A ′ of 1A and the flow passage 33 is cut off, and the flow passage 7A of the pilot valve 50A and the flow passage 33 are communicated with each other. Therefore, the pressure at the output port 7 of the pilot valve 50A is
It is guided to the flow path 33 via the flow path 7A. Now, temporarily, another pair of pilot valves 52A, 53 not shown in FIG.
It is assumed that the operating rod related to A is not operated and these pilot valves 52A and 53A are kept neutral.
In this case, the output ports of the pilot valves 52A and 53A both have the tank pressure, and the flow path 33 'shown in FIG. 6 connected to these flow paths 7B and 7B' also has the tank pressure.

Therefore, in the present case, the flow path 3 shown in FIG.
The pressure guided to 3 is higher than the tank pressure guided to the flow path 33 ', and the balls 32 constituting the third high pressure selecting means move upward in FIG. As a result, the ball 32 comes into contact with the seat portion of the sleeve 31 and connects the flow path 33 and the signal port 23 shown in FIG. In this way, the pressure at the output port 7 of the pilot valve 50A is given to the signal port 23. The pressure generated at the signal port 23 is directly in the form of hydraulic pressure as shown in FIG.
Of the pump 29 or, as is well known, controls the tilt controller 29A of the pump 29 as an electric signal via a pressure-electric converter.

Even when the operating rod 18 is swung in the direction of arrow B in FIG. 4, the directional control valve 11 is operated in substantially the same manner as described above, and the directional control valve 11 is gradually moved from the neutral position (a) to the switching position (c). It is possible to control the flow rate of the main circuit. At this time, the actuator 30 moves to the right.

[0031]

By the way, in the above-mentioned prior art, the high pressure selecting means for guiding the pressure of the output port to the signal port 23 are balls 24, 24 ', 32, respectively.
And the first, second, and third high-voltage selecting means including the sleeves 25, 25 ', and 31, and the third high-voltage selecting means is provided below the plane area including the first and second high-voltage selecting means. The included plane area is set. That is, since the high-voltage selecting means is arranged so as to be stacked in two stages, there is a problem in that the shape and size of the casing 1 in the height direction becomes large, which causes an increase in size.

In order to prevent the casing 1 from increasing in size, it is conceivable that only the first, second, and third high-pressure selecting means are formed as separate independent valves.
When configured in this way, the pilot valves 50A, 5
1A, 52A, 53A casing 1, and a means for connecting the valves of the first, second, and third high-pressure selecting means, which are separate bodies, are required, and the number of parts such as connection joints and pipes is reduced. This may increase the production cost, increase the manufacturing cost, and cause a problem such as contamination due to oil leakage from the connecting joint and the piping portion.

In the prior art shown in FIGS. 4 to 7 described above, all the three high pressure selecting means are balls 24, 24.
Since it is a structure including ′ and 32, 3
Requires one sleeve 25, 25 ', 31 and also requires three blind plugs 26, 26', 34 for closing the sleeve 25, 25 ', 31 after insertion,
Furthermore, processing of the flow path for inserting the sleeves 25, 25 ', 31 and screw processing for mounting the blind plugs 26, 26', 34 are required, which eventually increases the number of parts and increases the number of processing steps. There is also a problem that the production cost is increased by these.

The present invention has been made in view of the above-mentioned circumstances in the prior art, and an object thereof is to include a high pressure selecting structure for guiding the pressure of the output port to the signal port in one plane area. , Balls, sleeves,
It is an object of the present invention to provide a pressure reducing valve type pilot valve device capable of reducing the number of blind plugs.

[0035]

To achieve this object, the invention according to claim 1 of the present invention supplies a pressure signal to a pump port, a tank port, and the outside as a common port in a casing. An output port that has a signal port and that communicates selectively with the pump port and the tank port in the casing and outputs the pilot pressure, and the output port is either the pump port or the tank port. Is disposed between the pusher and the spool, and the pusher is pushed by the operating rod to slide the spool. The pusher is arranged between the pusher and the spool. A pressure reducing valve type pilot valve having a setting spring for setting the pressure on the output port side by the spool; In the pressure reducing valve type pilot valve device, which is arranged in the casing in the middle of the two flow paths and has a high pressure selecting means including a ball for selecting and extracting a high pressure of the pressures of the two flow paths, the four pilots In each of the valves, a small diameter portion provided on the spool, a communication passage communicating with the small diameter portion, a spool formed in the vicinity of the small diameter portion and the casing, and having a predetermined movement amount of the pusher or more Along with the movement, a selection flow path for selectively communicating the output port and the communication passage via the small diameter portion is provided, and the signal port and the tank port are constantly provided in the casing. A throttle is provided that communicates to the extent that enables depressurizing operation by a spool, and the high-voltage selecting means is arranged between each of the communication channels and the signal port, The pressure derived from serial output port in the communication passage through the selected channel, are the construction leading to the signal port through the high-pressure selection means.

[0036]

The present invention has the above-mentioned structure,
When each of the four pilot valves is in neutral, the output ports of all pilot valves become tank pressure, and
The signal port is also kept at the tank pressure by the throttle connected to the tank port.

From this state, for example, when any one of the predetermined pair of pilot valves is operated, the corresponding pusher moves by a predetermined amount, the corresponding spool moves, and the corresponding output port changes. It communicates with the corresponding communication channel via the corresponding selection channel. Therefore, the pressure of the corresponding output port is given to the high pressure selecting means through the corresponding selection flow path and communication flow path. Here, for example, if another pair of pilot valves is not operated, the ball forming the high-pressure selecting means moves by the pressure given through the corresponding communication passage described above, and the ball of the corresponding output port is moved. Pressure is applied to the signal port via this high pressure selection means.

In carrying out such an operation, the communication passages provided corresponding to the output ports of the four pilot valves can all be provided in the same plane area. When any one of the above-mentioned predetermined pair of pilot valves or another pair of pilot valves is operated, the first output port of one pilot valve of the predetermined pair of pilot valves is operated. Pressure is taken out through the corresponding communication passage, and similarly, the second pressure at the output port of one pilot valve of another pair of pilot valves is taken out through the corresponding communication passage. The high pressure selecting means including the balls may apply the larger one of the first pressure and the second pressure to the signal port. From such a relationship, only one high pressure selecting means including the ball is required, and this high pressure selecting means can also be arranged in the plane area including the above-mentioned four communication channels. Therefore, a high pressure selection structure for directing the pressure of the output port of any of the four pilot valves to the signal port can be included in one planar area.

Since only one high-voltage selecting means including a ball needs to be provided, the ball, the sleeve, the blind plug, and the associated processing are each formed by 2 in comparison with the prior art.
It can be reduced one by one.

The circuit withdrawal pressure generated at the signal port or the like can be released to the tank through the throttle.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a pressure reducing valve type pilot valve device of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a hydraulic circuit including an embodiment of a pressure reducing valve type pilot valve device of the present invention, and FIG. 2 is a structure near a lower portion of a spool of a pressure reducing valve type pilot valve constituting the embodiment shown in FIG. FIG. 3 is an enlarged sectional view, and FIG. 3 is a sectional view taken along the arrow A in FIG.

In FIGS. 1 to 3, the same components as those shown in FIGS. 4 to 7 are designated by the same reference numerals. That is, also in this embodiment, the casing 1 that constitutes the main body of the pressure reducing valve type pilot valve device is provided, and in this casing 1, a pump port into which the pressure oil from the hydraulic pump 2 serving as the pilot hydraulic pressure source flows as a common port. Three
, A tank port 5 that is in constant communication with the tank 4, and a signal port 46 that supplies a pressure signal to the outside.

In the casing 1, as shown in FIG. 3, four pressure reducing valve type pilot valves 50, 51, 5 are provided.
2, 53, but only two pilot valves 50, 51 are shown in FIG. The pilot valve 5
The constituent elements of the pilot valve 51 corresponding to the constituent elements of 0 are marked with “′”.

As shown in FIG. 1, a pair of pilot valves 5
0 and 51 are provided in the vicinity of the spring chambers 6 and 6 ′ and spring chambers 6 and 6 ′ which are in continuous communication with the tank port 5 and have step portions 6A and 6A ′. The output ports 7 and 7'and the pressure chambers 8 and 8'which are in constant communication with the output ports 7 and 7'are provided.

The casing 1 has a tank port 5
And the output ports 7, 7'between the flow paths 9, 9 ', respectively.
And the flow paths 10 and 10 ′ are formed between the output ports 7 and 7 ′ and the pump port 3, respectively. The output ports 7 and 7'described above are connected to the hydraulic pilot section 11 of the directional control valve 11 provided in the middle of the main circuit.
Pilot pressure is introduced to A and 11B via pilot lines 21A and 21B, and the directional control valve 11 is controlled to be switched.

Further, 13 and 13 'are bushings fitted to the casing 1 on the upper end side of the spring chambers 6 and 6'and prevented from coming off by the upper lid 14, and 15 and 15' are bushings 1.
The pushers are slidably inserted into the corresponding ones of the bushings 3 and 13 ', and the tip ends thereof project upward from the bushings 13 and 13', respectively. These pushers 15,
The base end side of 15 'engages with the lower end side of each of the bushings 13, 13', and is prevented from coming off from the bushings 13, 13 '. Also, the pushers 15, 15
Circular recesses 15A and 15A 'are formed in the center of the base end side of the ′. These pushers 15 and 15 'are axially pressed by the pressing portions 18A and 18A' of the operating rod 18. The operating rod 18 is swingably attached to a mounting member 19 projecting upward from the central portion of the upper end side of the casing 1 via a pin 20.

In the spring chambers 6 and 6 ', return springs 16 and 16' for returning the pushers 15 and 15 'to their initial positions (neutral positions), and the pushers 15 and 15', respectively.
Setting spring 1 for setting the pressure according to the amount of pushing operation of ‘
7, 17 'are arranged.

The hydraulic circuit shown in FIG. 1 also includes a relief valve 22 that regulates the pressure of the hydraulic oil discharged from the hydraulic pump 2, an actuator 30 whose drive is controlled by the direction switching valve 11 described above. A main circuit hydraulic pump 29 that supplies pressure oil that drives the actuator 30; a prime mover 28 that drives the main circuit hydraulic pump 29 and the hydraulic pump 2 that supplies the pilot pressure described above;
A tilt control unit 29A for controlling the discharge amount of the main circuit hydraulic pump 29 and a signal passage 27 for guiding a pressure signal for driving the tilt control unit 29A are provided.

The configuration described above is as shown in FIG.
~ It is the same as the prior art shown in FIG. The casing 1 described above, the pump port 3 formed in the casing 1, and the tank port 5 formed in the casing 1
A spring chamber 6 formed in the casing 1, an output port 7 and a pressure chamber 8, flow paths 9 and 10, a bushing 13 and a pusher 15, a return spring 16 and a setting spring 17.
A spool 40, a communication channel 42A, and a selection channel 43 described later
One pilot valve 50 is constituted by and.

Further, the casing 1 described above, the pump port 3 formed in the casing 1, the tank port 5 formed in the casing 1, the spring chamber 6'formed in the casing 1, the output port 7'and the pressure chamber. 8 ', the flow paths 9'and 10', the bushing 13 ', and the pusher 15'.
A return spring 16 ', a setting spring 17', a spool 40 ', a communication passage 42A' and a selection passage 43 'which will be described later.
Another pilot valve 51 is constituted by and.

In particular, for example, the spool 40 constituting the pilot valve 50 has a large diameter portion 40F facing the pressure chamber 8.
And a small diameter portion 40B extending from the large diameter portion 40F upwardly and slenderly and extending to the spring chamber 6, and a small diameter portion 40B.
An annular portion 40D provided on the upper end of the annular portion 40C that faces the recess 15A of the pusher 15 and slides in the flow path 9 and connects and disconnects the tank port 5 and the output port 7.
And a large diameter portion 40A that slides in the flow path 10 and connects and disconnects the pump port 3 and the output port 7. Further, a small diameter portion 40E is provided between the large diameter portion 40A and the large diameter portion 40F. The small diameter portion 40E is located so as to face the communication passage 42A formed in the casing 1. Between the large-diameter portion 40F connected to the small-diameter portion 40E and the casing 1, the selection channel 4 for selectively communicating the pressure chamber 8 with the above-mentioned communication channel 42A via the small-diameter portion 40E.
3 is formed. The large diameter portion 40F of the spool 40 connects and disconnects the selection channel 43 and the communication channel 42A, that is, the output port 7 that communicates with the pressure chamber 8 and the communication channel 42A.

Similarly, the spool 40 'constituting another pilot valve 51 has a large diameter portion 40F' facing the pressure chamber 8 ',
A small-diameter portion 40B 'extending upward from the large-diameter portion 40F' and extending to the spring chamber 6'and a small-diameter portion 40B '.
The recess 15A 'of the pusher 15' is provided at the upper end of B '.
While sliding in the flow path 9'and the head portion 40C 'facing the annular portion 40D' that connects and shuts off the tank port 5 and the output port 7 ', and slides in the flow path 10', It is provided with a large diameter portion 40A 'which connects and disconnects the pump port 3 and the output port 7'. Also, the large diameter portion 40A
A small diameter portion 40E 'is provided between the ??? and the large diameter portion 40F'. The small diameter portion 40E 'is located so as to face the flow path 42A' formed in the casing 1. This small diameter part 4
Between the large diameter portion 40F ′ connected to 0E ′ and the casing 1, there is provided a selection flow passage 43 ′ for selectively communicating the pressure chamber 8 ′ with the above-mentioned communication flow passage 42A ′ via the small diameter portion 40E ′. Has been formed. Due to the large-diameter portion 40F 'of the spool 40', the selection flow channel 43 'and the communication flow channel 42A', that is, the output port 7'communication with the pressure chamber 8'and the communication flow channel 4 '.
2A 'is connected and cut off.

Another pair of pilot valves 52 and 53 not shown in FIG.
It has almost the same configuration as 51.

Thus, the pilot valve 50 shown in FIG.
51, 52, 53 communication channels 42A, 42A ', 42
As shown in FIG. 3, a ball 45 and a sleeve 44 are included between B and 42B ′ and the signal port 46 that supplies a pressure signal to the outside, and the pressure on the communication flow paths 42A and 42A ′ side,
A high-pressure selecting means for taking out the larger one of the pressures on the communication passages 42B, 42B 'side is arranged, and the end of the sleeve 44 is closed by a blind plug 48.

Inside the spools 40, 40 'of the pilot valves 50, 51, through the high-pressure selecting means including the communication passages 42A, 42A' shown in FIG. As shown in FIG. 1, throttles 47 and 47 'are provided for allowing the signal port 46 and the tank port 5 to communicate with each other at all times. These diaphragms 47, 47 'are set to have relatively small apertures so as to enable the pressure reducing operation by the spools 40, 40'. Corresponding throttles 47, 47 'are also provided inside the spools of the pilot valves 52, 53 (not shown).

The operation of the embodiment thus configured is as follows. Temporarily, the operating rod 18 for operating the predetermined pair of pilot valves 50, 51 shown in FIG. 1 and another pair of pilot valves 52, 53 not shown in FIG.
It is assumed that both of the operating rods for operating are held neutral. Here, when the operating rod 18 shown in FIG. 1 is in the neutral position, the large diameter portions 40A, 40A of the spools 40, 40 '.
′ Each closes the flow path 10, 10 ′, and the annular portion 40
Since D and 40D 'respectively open the flow paths 9 and 9', the output ports 7 and 7'communicate with the tank port 5 through the flow paths 9 and 9'and are blocked from the pump port 3 to reduce the low pressure. Be put in a state. As a result, the hydraulic pilot portions 11A and 11B of the directional control valve 11 become equal in pressure, and the directional control valve 11 is maintained at the neutral position (a) as shown in the figure.

At this time, the pilot valves 50, 51
Each of the communication channels 42A, 42A 'of the spool 4
Tank port 5 through the 0,40 'throttle 47,47'
Communicate with Similarly, in the pilot valves 52 and 53 (not shown), each of the communication passages 42B and 42B 'communicates with the tank port 5 via the throttle of the corresponding spool, so that the ball 45 constituting the high pressure selection means shown in FIG. 3, the tank pressure acts in the vertical direction, and the signal port 46 is also kept at the tank pressure accordingly.

From such a state, the operating rod 1 shown in FIG.
When 8 is tilted in the direction of arrow A, the pusher 15 moves axially downward by the pressing portion 18A, and the spool 40 slides axially downward via the setting spring 17 according to the operation amount at this time. As a result, the annular portion 40D of the spool 40 closes the flow path 9, and the tank port 5 and the output port 7
Are blocked, the flow path 10 opens as the large diameter portion 40A moves, and the pump port 3 and the output port 7 communicate with each other. Therefore, the output port 7 and the pressure chamber 8 have high pressure. The pressure in the pressure chamber 8 acts as a feedback pressure on the spool 40 and pushes the spool 40 upward in the axial direction, whereby the setting spring 17 is compressed from the preset state and bends.

When the annular portion 40D of the spool 40 opens the flow passage 9 again, the output port 7 communicates with the tank port 5, and the large diameter portion 40A closes the flow passage 10.
Since the pressures in the output port 7 and the pressure chamber 8 drop,
The spool 40 slides axially downward again due to the spring load of the setting spring 17, the setting spring 17 returns to the preset state, and the large diameter portion 40A of the spool 40 opens the flow path 10 again. As a result, the pressure inside the output port 7 and the pressure chamber 8 rises.

As described above, the spool 40 has the structure shown in FIG.
Similar to the one shown in Fig. 1, when the pusher 15 is pressed by a small amount by repeating sliding up and down in the axial direction, the setting spring 17
The pilot pressure corresponding to the preset load is supplied from the output port 7 to the hydraulic pilot portion 11A of the direction switching valve 11 via the pilot conduit 21A.

When the operating rod 18 is swung further in the direction of arrow A than in the above-mentioned state and the pushing operation amount of the pusher 15 is increased, the setting spring 17 slides the spool 40 axially downward with a force equal to or greater than the preset load. As the spool 40 repeatedly opens and closes the flow paths 9 and 10,
The pressure in the output port 7 is set to a pressure state corresponding to the spring load (deflection amount) of the setting spring 17.

That is, a spring load corresponding to the pressing operation amount of the pusher 15 is generated in the setting spring 17, and the pressure in the output port 7 is controlled in accordance with this spring load. Then, the direction switching valve 11 is switched from the neutral position (a) to the left switching position (b) with a stroke amount corresponding to the pressure (pilot pressure) in the output port 7.

When the pushing operation amount of the pusher 15 is further increased, the head portion 40C of the spool 40 comes into contact with the upper surface of the recess 15A of the pusher 15, and the setting spring 17 bends further. Instead, the spool 40 slides axially downward together with the pusher 15.
As a result, regardless of the pressure in the pressure chamber 8, the output port 7
Is maintained in communication with the pump port 3, and the pressure in the output port 7 is equal to the pressure in the pump port 3 (that is, the pressure oil pressure from the hydraulic pump 2 set by the relief valve 22). Be put in a state. Then, the direction switching valve 11 is completely switched to the left switching position (b) by this pressure.

Thus, the pusher 1 by the operating rod 18
The pressure in the output port 7 is set until the head spring 40C of the spool 40 comes into contact with the upper surface of the recess 15A of the pusher 15 while the setting spring 17 is gradually compressed from the preset state in accordance with the pressing operation of 5. The pressure is controlled to be reduced to a value corresponding to the spring load of the working spring 17, and the directional switching valve 11 can be gradually switched from the neutral position (a) to the switching position (b) by the pressure in the output port 7. . Then, by controlling the switching from the neutral position (a) to the switching position (b) of the direction switching valve 11, the amount of pressure oil flowing into the main circuit via the direction switching valve 11 is gradually changed from a small flow rate to a large flow rate. And the flow rate can be controlled. These operations are the same as those shown in FIG. 4 described above.

Particularly in this embodiment, when the pusher 15 is pushed by the operating rod 18 until the pusher 15 moves by a predetermined movement amount and the pilot pressure is introduced into the pressure chamber 8, the head 40F of the spool 40 keeps pushing until that time. The closed selection channel 43 opens, the pressure chamber 8 and the communication channel 42A communicate with each other through the small diameter portion 40E of the spool 40, and the pilot pressure of the pressure chamber 8 communicates with the selection channel 43 through the selection channel 43. 42A
Is supplied to. The pilot pressure supplied to the communication passage 42A is guided to the high pressure selecting means shown in FIG. 3, but since the communication passages 42B and 42B 'are now tank pressures, the ball 45 is shown in FIG. Moving upward, the communication channel 42
The pressure of A is led to the signal port 46, and the signal port 4
6 to the tilt control unit 29A of the pump 29. As a result, the tilt control unit 29A operates, and the discharge amount of the pump 29 is controlled according to the pilot pressure introduced into the pressure chamber 8 described above.

Even when the operating rod 18 is tilted in the direction of arrow B in FIG. 1, the same operation as described above is performed. That is, when the pilot pressure is introduced into the pressure chamber 8 ', the selection flow passage 43' which has been closed by the head portion 40F 'of the spool 40' until then opens, and the pressure chamber 8'and the communication flow passage 4 '.
2A 'communicates with the small diameter portion 40E' of the spool 40 ', and the pilot pressure of the pressure chamber 8'is supplied to the communication channel 42A' via the selection channel 43 '. This communication channel 4
The pilot pressure supplied to 2A ′ moves the ball 45 of the high pressure selecting means shown in FIG. 3, is supplied to the signal port 46, and is supplied from this signal port 46 to the tilt control unit 29A of the pump 29. As a result, the tilting control unit 29A operates, and the discharge amount of the pump 29 is controlled according to the pilot pressure guided to the pressure chamber 8'described above.

Such an operation is the same when the other operating rod (not shown) is operated to operate the pilot valves 52 and 53. Further, when the operating rod 18 shown in FIG. 1 and the other operating rod (not shown) are simultaneously operated, the pressure introduced into the communication passages 42A and 42A ′, the communication passage 42
The larger pressure of the pressures introduced to B and 42B 'is selected by the high pressure selecting means including the ball 45 and stored in the signal port 46.

Further, in this embodiment, the spools 40, 40
Signal port 4 by the diaphragms 47, 47 ', etc. provided on the
6 and the tank port 5 communicate with each other to the extent that they do not hinder the depressurizing operation due to the sliding of the spools 40, 40 '.
As described above, the withdrawal pressure of the circuit such as the signal passage 27 at the time of neutrality can be released to the tank 4 via the throttles 47, 47 '.

In the above embodiment, the pilot valve 5
0, 51 etc. spool 40, 40 ', etc., signal port 4
6 and the tank port 5 are provided with throttles 47, 47 'for communicating with each other within a degree that does not hinder the depressurizing operation, but the present invention is not limited to this. 5, a passage similar to the throttle 47 is provided in this passage, and the communication passage 42
A configuration may be employed in which a passage that connects either B or 42B 'to the tank port 5 is provided, and a throttle similar to the throttle 47 or the like is provided in this passage.

In the embodiment constructed as described above, the selection passage 43 and the communication passage 42A provided in the pilot valve 50, and the selection passage 43 'and the communication passage 4 provided in the pilot valve 51.
2A 'and the like have a high-pressure selecting function that does not require balls, sleeves, and blind plugs, and the communication passages 42A, 42A', 42B of the pilot valves 50, 51, 52, 53 having such a high-pressure selecting function. , 42B 'can be arranged in the same plane area as shown in FIG. 3, and balls for guiding the pressure introduced in these communication flow paths 42A, 42A', 42B, 42B 'to the signal port 46. Only one high-pressure selecting means including the sleeve 46 and the sleeve 44 needs to be provided.
A, 42A ', 42B, 42B' can be arranged together in a plane area, and from these facts, the output ports 7, 7'of the pilot valves 50, 51, 52, 53 are
A high pressure selection structure that directs pressure, etc. to the signal port 46 can be included in one planar area. As a result, the height and shape of the casing 1 can be suppressed to a low level, and the size can be reduced.

Therefore, it is not necessary to provide the high-voltage selection structure portion separately from the casing 1, and the increase in the number of parts and the manufacturing cost will not occur by providing such a separate body. There is no concern about oil leakage due to installation on the body.

Further, in this embodiment, as the high pressure selecting structure, it is sufficient to provide one high pressure selecting means including one ball 46, sleeve 44 and blind plug 48, respectively. Can reduce the number of man-hours for processing the casing 1 for
With these, the production cost can be reduced.

Further, as described above, since the circuit withdrawal pressure can be released to the tank 4 via the throttles 47, 47 ', etc., the tilt control section 29A controlled by the pressure signal output from the signal port 46. It is possible to realize accurate drive control for the control device.

[0074]

Since the present invention is configured as described above, a high pressure selecting structure for guiding the pressure of the output port of each pilot valve to the signal port can be included in one plane area. The shape and size of the casing in the height direction can be suppressed to a low level, and miniaturization can be realized. Further, the number of parts of the ball, the sleeve, and the blind plug can be reduced as compared with the conventional one, and accordingly, the number of man-hours for processing the casing can be reduced, and thus the manufacturing cost can be reduced. . Further, the muffled pressure of the circuit can be released to the tank through the throttle, and accurate drive control for the control device controlled by the pressure signal output from the signal port can be realized.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a hydraulic circuit including an embodiment of a pressure reducing valve type pilot valve device of the present invention.

FIG. 2 is an enlarged sectional view showing a structure near a lower portion of a spool of the pressure reducing valve type pilot valve constituting the embodiment shown in FIG.

3 is a cross-sectional view taken along arrow A in FIG.

FIG. 4 is a circuit diagram showing a hydraulic circuit including a conventional pressure reducing valve type pilot valve device.

5 is a sectional view taken along the arrow B in FIG.

6 is a sectional view taken along the arrow C in FIG.

FIG. 7 is a diagram in which the pressure reducing valve type pilot valve device shown in FIG. 4 is represented by a circuit symbol.

[Explanation of symbols]

 1 Casing 3 Pump Port 4 Tank 5 Tank Port 6 Spring Chamber 6 ′ Spring Chamber 7 Output Port 7 ′ Output Port 8 Pressure Chamber 8 ′ Pressure Chamber 9 Flow Path 9 ′ Flow Path 10 Flow Path 10 ′ Flow Path 13 Bushing 13 ′ Bushing 14 Upper lid 15 Pusher 15 'Pusher 16 Return spring 16' Return spring 17 Setting spring 17 'Setting spring 18 Operating rod 40 Spool 40' Spool 40A Large diameter portion 40A 'Large diameter portion 40B Small diameter portion 40B' Small diameter portion 40C Head part 40C 'Head part 40D Annular part 40D' Annular part 40E Small diameter part 40E 'Small diameter part 40F Large diameter part 40F' Large diameter part 42A Communication channel 42A 'Communication channel 42B Communication channel 42B' Communication channel 43 Selective flow Channel 43 'Selection channel 44 Sleeve (high-voltage selection means) 45 Ball (high-voltage selection means) 46 Signal port 47 Throttle 47 'Throttle 48 Blind plug 50 Pressure reducing valve type pilot valve 51 Pressure reducing valve type pilot valve 52 Pressure reducing valve type pilot valve 53 Pressure reducing valve type pilot valve

Claims (2)

[Claims] 1. A casing has a pump port, a tank port, and a signal port for supplying a pressure signal to the outside as a common port, and selectively communicates with the pump port and the tank port inside the casing, respectively. Then, an output port for outputting the pilot pressure, a spool for selectively communicating the output port with any of the pump port and the tank port, and a push rod operated by the operating rod to slide the spool. Four pressure reducing valve type pilot valves having a pusher and a setting spring which is arranged between the pusher and the spool and which sets the pressure on the output port side by the spool according to the push operation amount of the pusher. Further, in the above-mentioned casing, disposed in the middle of the two flow paths, In a pressure-reducing valve type pilot valve device having high-pressure selecting means including balls for selectively extracting high pressure, in each of the four pilot valves, a small diameter portion provided on the spool, and a communication passage communicating with the small diameter portion, A selection that is formed between the spool and the casing near the small diameter portion and selectively communicates the output port and the communication passage via the small diameter portion with the movement of the pusher by a predetermined amount or more. A flow passage is provided, and a throttle that constantly connects the signal port and the tank port to each other so as to enable the pressure reducing operation by the spool is provided in the casing. The high-pressure selecting means is arranged between the output port and the port, and the pressure introduced from the output port to the selection channel via the selection channel is increased. A pressure reducing valve type pilot valve device, characterized in that the pressure reducing valve type pilot valve device is led to the signal port via a high pressure selecting means. 2. The pressure reducing valve type pilot valve device according to claim 1, wherein the throttle is provided inside the spool.