JP2009041616A - Control device using neutral cut valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device which does not increase cost while not increasing a device size as a whole. <P>SOLUTION: A first circuit system 6 and a second circuit system 23 are provided and a specific switching valve 5 having a reproducing function for regenerating returning fluid from a specific actuator 14 to the supply side of the specific actuator 14 is provided at least at the first circuit system 6. A throttle for regeneration is provided at a passage 9 which is used as a returning side when the specific switching valve 5 is switched to a regeneration position. A center open passage 24 for guiding a supply fluid of the second pump P2 to a tank when switching valves provided at the second circuit system 23 keep to hold their neutral positions is provided. The neutral cut valve 28 for opening and closing the center open passage 24 is provided at a most downstream position of the second circuit system 23. The neutral cut valve 28 is constituted of a spool valve and the throttle 29 for regeneration is also provided at the neutral cut valve 28. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device using a neutral cut valve, which is optimal for a construction machine having an arm cylinder and having a function of regenerating the return fluid of the arm cylinder to the supply side, for example.

For example, some construction machines equipped with an arm cylinder have a so-called regeneration function that returns the return fluid of the arm cylinder to the supply side. In order to perform this regeneration function, a regeneration restrictor is provided in the return side passage during regeneration, and the return fluid is supplied to the supply side with a pressure corresponding to the pressure loss when the return fluid passes through the restrictor. I try to play it.
A control device described in Patent Document 1 has been conventionally known as a control device having such a reproduction function.

  In the above-described conventional apparatus, the aperture indicated by reference numeral 52 in FIG. That is, the switching valve that controls the arm cylinder is slidably incorporated with the spool in the valve body, and the return fluid from the arm cylinder is regenerated to the supply side in accordance with the relative position of the spool. . A passage for regenerating the return fluid to the supply side is formed in the valve body, and the regeneration throttle (reference numeral 52 in the publication) is formed in the passage.

In addition to forming the regeneration throttle on the valve body of the switching valve as in the device described in Patent Document 1, for example, the regeneration throttle is used as a switching valve that controls a specific actuator that requires regeneration. On the other hand, it can be considered to be external. FIG. 6 and FIG. 7 show examples in which the switching valve is externally attached.
FIG. 6 shows a hydraulic control circuit for a power shovel that is a construction machine, and includes a first pump P1 and a second pump P2. Then, the traveling switch valve 1, the standby switching valve 2, the turning switching valve 3, the boom II switching valve 4 and the arm I switching valve 5 are sequentially connected to the first pump P1 from the upstream side thereof. These switching valves 1 to 5 constitute a first circuit system 6. When each of these switching valves 1 to 5 is in the neutral position as shown in the drawing, the center open passage 7 is opened, and the fluid discharged from the first pump P1 is guided to the tank T via the tank passage 11. I am doing so. In addition, the code | symbol 8 is a parallel channel | path and connects each switching valve 1-5 in parallel with respect to the 1st pump P1.

Then, when the arm I switching valve 5 located on the most downstream side is switched to the regeneration position which is the left side of the drawing, the regeneration passage 9 on the return side is externally attached to the arm I switching valve 5. The reproduction aperture means 10 is connected. The regeneration throttle means 10 communicates with the tank T via the tank passage 11, and when fluid flows from the regeneration passage 9 to the tank T via the regeneration throttle means 10, the regeneration passage 9 has a pressure loss component. The pressure is generated.
The fluid holding the pressure in this way is supplied to the supply side passage 13 via the check valve 12 and supplied to the piston side chamber 14 a of the arm cylinder 14. That is, the return fluid from the rod side chamber 14 b of the arm cylinder 14 is regenerated to the piston side chamber 14 a of the arm cylinder 14 via the regeneration passage 9.

In addition, when the fluid is regenerated in the piston side chamber 14a of the arm cylinder 14 as described above, the load is acting on the arm cylinder 14 in the direction of the arrow 15 while the rod of the arm cylinder 14 is extended. When performing excavation work, the load direction is reversed. At this time, the check valve 12 is closed by the load pressure so that the pressure fluid from the first pump P1 does not escape to the regeneration passage 9 side.
When the arm I switching valve 5 is switched to the right in the drawing, the supply fluid from the first pump P1 is supplied to the rod side chamber 14b of the arm cylinder 14 via the supply side passage 13, and the piston The entire amount of return fluid in the side chamber 14a is returned to the tank T.

  On the other hand, from the upstream side of the second pump P2, the straight travel switching valve 16, the travel switching valve 17, the bucket switching valve 18, the boom I switching valve 19, the arm II switching valve 20, and the standby switching are provided. The valves 21 are sequentially connected, and a neutral cut valve 22 is connected to the most downstream side. These switching valves 16-21 constitute the second circuit system 23. When each switching valve 16-21 is in the neutral position as shown, its center open passage 24 is opened and the second pump P2 is opened. The fluid discharged from the tank is guided to the tank T. In addition, the code | symbol 25 is a parallel channel | path, and connects each switching valve 16-21 to the 2nd pump P2 in parallel.

A branch passage 26 is connected to the center open passage 24 between the neutral cut valve 22 located on the most downstream side and the standby switching valve 21 located immediately upstream thereof, so that the neutral cut valve 22 has a cut position. When held, the pressure fluid supplied from the second pump P2 to the center open passage 24 is supplied to another circuit system (not shown) via the branch passage 26.
Japanese Patent No. 3388799

  Since the regeneration throttle is formed in the valve body of the switching valve that controls a specific actuator that requires regeneration, there is a problem that the processing cost of the regeneration throttle is increased. The reason is as follows. is there. In the valve body of the switching valve that controls the actuator, various passages are formed and devices such as a relief valve are incorporated, so the position where the regeneration throttle can be formed is limited, and the position is also very narrow. The fact is that it has to be a difficult place. In order to form the regeneration diaphragm in such an extremely narrow portion, there is a problem that the processing cost is inevitably increased.

As a means for solving the above problem, if the regeneration throttle means is externally attached to the regeneration switching valve as in the apparatus of FIG. 6, the regeneration throttle must be formed in a narrow area. Is solved. However, in this case, another problem arises in that the entire apparatus is enlarged by the amount of the reproduction aperture.
Moreover, in the case of the current power shovel in which the regeneration throttle means is externally attached to the regeneration switching valve, as shown in FIG. 7, a useless space 27 is formed on the first circuit system 6 side. There was also a problem.
FIG. 7 is a side view of the valve block as viewed from the spool hole side, and the portions denoted by reference numerals as switching valves, regeneration throttle means or neutral cut valves indicate the end surfaces of the spool holes.
An object of the present invention is to provide a control device that does not increase the size of the entire device and does not increase the cost.

  The present invention includes a first circuit system connected to the first pump and provided with a plurality of switching valves, and a second circuit system connected to the second pump and provided with a plurality of switching valves, and at least a first circuit system. The circuit system is provided with a specific switching valve having a regeneration function for regenerating the return fluid from the specific actuator to the supply side of the specific actuator, and when the specific switching valve is switched to the regeneration position, In the second circuit system, a regeneration throttle is provided in the return side passage or a passage communicating therewith, and the return fluid is regenerated with the pressure corresponding to the pressure loss when the fluid passes through the regeneration throttle. The switching valve provided in the center valve has a center open passage for guiding the supply fluid of the second pump to the tank when they are in the neutral position. Downstream, it is to assume control device provided with a neutral cut valve for opening and closing the center opening passage.

The first invention is characterized in that the neutral cut valve is constituted by a spool valve on the premise of the control device, and the regeneration throttle is provided in addition to the neutral cut valve.
A second aspect of the present invention is a valve body of the neutral cut valve, a tank passage, a regeneration passage communicating with a return passage when a specific switching valve having a regeneration function is switched to a regeneration position, These two passages are characterized in that they are configured to communicate with each other through a regeneration throttle formed by a gap formed between the spool hole and the spool.
The third invention allows the valve body of the neutral cut valve to flow only from the regeneration passage to the passage communicating with the supply-side passage when the specific switching valve is switched to the regeneration position. It is characterized in that a check valve for preventing backflow is provided.

  According to the first aspect, since the regeneration throttle is provided along with the neutral cut valve, the processing cost can be reduced as compared with the case where the regeneration throttle is formed on the specific switching valve as in the prior art. This is because the neutral cut valve only needs to turn on and off the center open passage, so the configuration is simpler than the switching valve for controlling the actuator, and there is sufficient space for forming the regeneration throttle. .

According to the second aspect of the present invention, since the gap formed between the spool hole formed in the neutral cut valve and the spool is used as the regeneration throttle, the regeneration throttle can be formed by processing the spool hole and the spool. Therefore, the processing cost is further reduced.
Moreover, since the neutral cut valve has both the neutral cut function and the regeneration throttle function, the neutral cut valve may be provided on the first circuit system side or the second circuit system side. , The degree of freedom in its design increases. Therefore, when the apparatus of the present invention is used in an existing power shovel, it is not necessary to secure a useless space.
According to the third aspect, since the check valve is also provided in the valve body of the neutral cut valve, the overall size can be reduced and the processing cost can be reduced.

The embodiment shown in FIGS. 1 to 5 shows a hydraulic control circuit for a power shovel that is a construction machine, and the difference from the conventional one is the connection position of the neutral cut valve 28 and its structure. Others are the same as in the prior art shown in FIG. Therefore, the same constituent elements as those in the prior art will be described using the same reference numerals as those in FIG.
The hydraulic control circuit for the power shovel shown in FIG. 1 includes a first pump P1 and a second pump P2. Then, the traveling switch valve 1, the standby switching valve 2, the turning switching valve 3, the boom II switching valve 4 and the arm I switching valve 5 are sequentially connected to the first pump P1 from the upstream side thereof. These switching valves 1 to 5 constitute a first circuit system 6. When each of these switching valves 1 to 5 is in the neutral position as shown in the drawing, the center open passage 7 is opened, and the fluid discharged from the first pump P1 is guided to the tank T via the tank passage 11. I am doing so. In addition, the code | symbol 8 is a parallel channel | path and connects each switching valve 1-5 in parallel with respect to the 1st pump P1.
The arm I switching valve 5 constitutes the regeneration switching valve of the present invention.

A neutral cut valve 28 is connected to the passage 9 on the return side when the arm I switching valve 5 located on the most downstream side is switched to the regeneration position on the left side of the drawing. The neutral cut valve 28 is provided with a regeneration throttle 29 so that the regeneration passage 9 and the tank passage 11 are always in communication with each other through the regeneration throttle 29 regardless of the switching position of the neutral cut valve 28. Yes.
By connecting the regeneration passage 9 and the tank passage 11 via the regeneration throttle 29 as described above, when the fluid flows from the regeneration passage 9 to the tank T via the regeneration throttle 29, the regeneration passage 9 generates a pressure corresponding to the pressure loss.
The fluid holding the pressure in this way is supplied to the supply side passage 13 via the check valve 12 and supplied to the piston side chamber 14 a of the arm cylinder 14. That is, the return fluid from the rod side chamber 14 b of the arm cylinder 14 is regenerated to the piston side chamber 14 a of the arm cylinder 14 via the regeneration passage 9.

In addition, when the fluid is regenerated in the piston side chamber 14a of the arm cylinder 14 as described above, the load is acting on the arm cylinder 14 in the direction of the arrow 15 while the rod of the arm cylinder 14 is extended. When performing excavation work, the load direction is reversed. For this reason, the pressure in the piston side chamber 14a rises. At this time, the check valve 12 is closed by the load pressure so that the pressure fluid from the first pump P1 does not escape to the regeneration passage 9 side.
When the arm I switching valve 5 is switched to the right in the drawing, the supply fluid from the first pump P1 is supplied to the rod side chamber 14b of the arm cylinder 14 via the supply side passage 13, and the piston The entire amount of return fluid in the side chamber 14a is returned to the tank T.

On the other hand, from the upstream side of the second pump P2, the traveling straight travel switching valve 16, the traveling switching valve 17, the bucket switching valve 18, the boom I switching valve 19, the arm II switching valve 20, and the standby switching. The valves 21 are sequentially connected, and the second circuit system 23 is configured by these switching valves 16 to 21. In addition, the center open passage 24 on the downstream side of the standby switching valve 21 communicates with the above-described neutral cut valve 28 and is also connected to the branch passage 26.
When each of the switching valves 16 to 21 is in the neutral position as shown in the figure, the center open passage 24 is opened to guide the discharge fluid from the second pump P2 to the tank T. In addition, the code | symbol 25 is a parallel channel | path, and connects each switching valve 16-21 to the 2nd pump P2 in parallel.

  Further, the neutral cut valve 28 connected to the center open passage 24 can be switched to two positions. When the neutral cut valve 28 is at the right position in the figure, the center open passage 24 is communicated with the tank T through the tank passage 11. On the other hand, when the neutral cut valve 28 is switched to the left position in the drawing, the communication between the center open passage 24 and the tank passage 11 is cut off, and the pressure fluid supplied from the second pump P2 to the center open passage 24 is supplied to the branch passage 26. Through this, it supplies to other circuit systems which are not illustrated.

  2 and 3 specifically show the switching valve 5 for the arm I as the switching valve for regeneration and the neutral cut valve 28 connected to the switching valve 5. As shown in FIG. 2, the arm I switching valve 5 incorporates the spool 31 into the valve body 30 in a slidable manner, and keeps the spool 31 in the neutral position as shown in FIG. The center open passage 7 is kept open. When the pilot pressure is guided to the left pilot chamber 32 and the spool 31 is moved in the right direction in the drawing, the arm I switching valve 5 is switched to the regeneration position. That is, while the center open passage 7 is closed, the pressure fluid led from the first pump P1 to the parallel passage 8 is led to the supply side passage 13, and one annular formed on the spool 31 from the supply side passage 13. The gas is supplied to the piston side chamber 14 a of the arm cylinder 14 via the groove 33 and one actuator port 34.

  At this time, the return fluid from the rod side chamber 14 b of the arm I switching valve 5 is guided to the regeneration passage 9 via the other actuator port 35 and the other annular groove 48. In the figure, reference numeral 12 is a check valve provided in the valve body 30 and permits only the flow from the regeneration passage 9 side to the supply side passage 13.

On the other hand, the neutral cut valve 28 connected to the arm I switching valve 5 has a spool hole 37 formed in the valve body 36, and a spool 38 is slidably incorporated in the spool hole 37 and both ends of the spool 38 are slidably mounted. In the pilot rooms 39 and 40. In the figure, reference numeral 41 denotes a centering spring provided in the pilot chamber 40.
The valve main body 36 is formed with an inflow passage 42 communicating with the center open passage 24 of the second circuit system 23 and a flow passage 43 communicating with the regeneration passage 9 of the arm I switching valve 5. is doing. A relay annular recess 44 communicating with the tank T is formed between the inflow path 42 and the flow path 43.

  Further, the spool 38 is formed with a first annular groove 45 and a second annular groove 46, and when the spool 38 is in the neutral position shown in the drawing, the inflow path 42 and the relay annular recess are interposed via the first annular groove 45. 44 is communicated to guide the fluid flowing from the inflow path 42 to the tank T. On the other hand, when the pilot pressure is guided to the pilot chamber 39 and the spool 38 is moved in the right direction in the figure, the inflow path 42 and the first annular groove 45 are different from each other, or the first annular groove 45 and the relay annular recess are In contrast, the communication between the inflow path 42 and the relay annular recess 44 is blocked. Therefore, the center open passage 24 of the second circuit system 23 is closed, and the fluid guided to the center open passage 24 is supplied to the branch passage 26.

  On the other hand, the second annular groove 46 always communicates the flow passage 43 and the relay annular recess 44 regardless of the movement position of the spool 38, and the depth of the second annular groove 46 is shallower than the first annular groove 45. is doing. By reducing the depth of the second annular groove 46 in this way, the gap between the bottom of the second annular groove 46 and the spool hole 37 is kept small, and this gap is used as the regeneration throttle 29. The function of the playback diaphragm 29 is as described above. As shown in FIG. 3, the gap for forming the regeneration diaphragm 29 may be formed as a recess 48 in the spool 38, and the gap between the recess 48 and the spool hole 37 may be used as the regeneration diaphragm 49. .

  In any case, in the embodiment shown in FIG. 2, the neutral cut valve 28 having a simple structure that originally has only a function of communicating the inflow path 42 and the relay annular recess 44 or blocking the communication is regenerated. Since the diaphragm 47 or 49 is formed, the processing itself is simplified, and the processing cost can be reduced accordingly. In addition, since the neutral cut valve 28 in this case is involved in either the first circuit system 6 or the second circuit system 23, the neutral cut valve 28 may be provided on either circuit system side. The degree of freedom increases. Therefore, as shown in FIG. 4, in the current excavator, the number of valves can be intentionally matched between the first circuit system 6 and the second circuit system 23, and a wasted space 27 as in the conventional case. Can no longer be made. 4 is a side view when viewed from the spool hole side, similarly to FIG.

  The apparatus shown in FIG. 5 incorporates the check valve 12 in the valve main body 36 of the neutral cut valve 28, and the function of this check valve 12 is the same as that of FIG. That is, even if the regeneration throttle 47 or 49 is provided in the valve main body 36 of the neutral cut valve 28, there is a space, so that the check valve 12 can be easily provided, and the arm I switching valve can be provided. There is an advantage that the inside of the valve body 30 can be simplified.

It is a circuit diagram. It is sectional drawing. FIG. 3 is a partial view showing an embodiment different from FIG. It is the side view which looked at the valve block from the spool hole side. It is sectional drawing of other embodiment which incorporated the check valve in the valve main body of the neutral cut valve. It is a conventional circuit diagram. It is the conventional side view which looked at the valve block from the spool hole side.

Explanation of symbols

P1 1st pump P2 2nd pumps 1-5 switching valve 6 1st circuit system 9 regeneration passage 11 tank passage 16-21 switching valve 23 2nd circuit system 24 center open passage 25 parallel passage 26 branch passage 28 neutral cut valve 29 Reducing throttle 36 Valve body 37 Spool hole 38 Spool

Claims (3)

  A first circuit system connected to the first pump and provided with a plurality of switching valves; a second circuit system connected to the second pump and provided with a plurality of switching valves; and at least the first circuit system A specific switching valve having a regeneration function for regenerating the return fluid from a specific actuator to the supply side of the specific actuator is provided, and when the specific switching valve is switched to the regeneration position, the return side becomes the return side. A regenerative restrictor is provided in the passage or a passage communicating therewith, and the return fluid is regenerated with the pressure corresponding to the pressure loss when the fluid passes through the regenerative restrictor, while the switching provided in the second circuit system The valves provide a center open passage for guiding the supply fluid of the second pump to the tank when they are in the neutral position, and at the most downstream of this second circuit system, In the control device provided with a neutral cut valve for opening and closing the centers open passage, along with constituting the neutral cut valve spool valve, the control device being characterized in that features the reproducing aperture to the neutral cut valve.   The neutral cut valve is provided with a tank passage and a regeneration passage communicating with a return passage when a specific switching valve having a regeneration function is switched to the regeneration position. 2. The control device according to claim 1, wherein the two passages are configured to communicate with each other via a regeneration throttle formed by a gap formed between the spool hole and the spool.   Check that the valve body of the neutral cut valve only allows flow from the regeneration passage to the passage that communicates with the supply-side passage when the specific switching valve is switched to the regeneration position, and prevents backflow. The control device according to claim 1 or 2, further comprising a valve.

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