JP2008014405A - Pressure rise circuit for construction machine and its supply part body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supply part body of a pressure rise circuit for a construction machine, capable of suppressing an increase in the size. <P>SOLUTION: The supply part body comprises a first block 21a and a second block 21b assembled together in an integral manner. In the first block 21a, a first pump port 50, a first pump passage 34, a second pump port 51, a second pump passage 35, and a tank passage 36 are formed. A first check valve 37 and a second check valve 38 are arranged in the first block 21a, and a main relief valve 39 is arranged over between the first block 21a and the second block 21b. An ordinary pressure slave valve 40 and a pressure rise slave valve 41 are arranged in the second block 21b on an orthogonal plane perpendicular to the ranging direction of multiple valves 2. A back pressure selector valve 42 is arranged in the second block 21b on the side of the first block 21a beyond the ordinary pressure slave valve 40 and the pressure rise slave valve 41, and a spool 54 of the back pressure selector valve 42 is arranged on the orthogonal plane. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a booster circuit for a construction machine and a pressure oil from a pump of the plurality of parts provided in a booster circuit for a construction machine formed as a multiple valve in which a plurality of parts are continuously provided. It is related with the supply part of the booster circuit of the construction machine which is a part supplied with.

  2. Description of the Related Art Conventionally, there is known a boosting circuit for a construction machine that increases the driving torque of the traveling motor by increasing the hydraulic pressure by changing the set pressure of the relief valve when only the traveling motor is driven in the construction machine (Patent Document). 1). That is, the booster circuit described in Patent Document 1 increases the hydraulic pressure when only the traveling motor is driven, and the hydraulic pressure becomes the normal set pressure when an actuator other than the traveling motor is driven in conjunction with the traveling motor. Set the relief valve pressure.

Japanese Unexamined Patent Publication No. Sho 62-21163 (page 7-8, FIG. 3)

  However, in the booster circuit of the construction machine described in Patent Document 1, as a mechanism for increasing the pressure by changing the back pressure of the relief valve (25), it is installed in the vent line of the relief valve to determine the normal set pressure. Either or both of the pilot relief valve (71), the pilot relief valve (72) that determines the pressure during pressure increase, and the travel operation valves (3, 6) that control the supply of pressure oil to the left and right travel motors are turned off. A valve (70) for switching to a pressure at the time of pressure increase when switching and a passage (62) as a release pilot passage for switching from the pressure setting at the time of pressure increase to the normal set pressure are required. A booster circuit of a construction machine having such a mechanism for boosting is formed as a multiple valve in which a plurality of parts are connected in series. And the mechanism for raising the pressure is provided in a supply part which is a part to which pressure oil from the pump is supplied in the plurality of parts. For this reason, there exists a problem that the supply part body will enlarge.

  Further, in the booster circuit of the construction machine, there is an auto idle signal path that generates an auto idle signal for controlling the rotation speed of the engine according to the operating state of each actuator by detecting the operation of each actuator of the construction machine. May be provided. Further, in the booster circuit of the construction machine, when the first to third pumps are provided, the pressure oil supplied from the third pump is detected by detecting that the left and right traveling motors and other actuators are operated. A traveling merging pilot passage for generating a traveling merging signal for switching a merging switching valve for merging with the pressure oil supplied from the first pump and the second pump may be provided. In the booster circuit described in Patent Document 1, since the release pilot path for switching from the pressure setting at the time of boosting to the normal set pressure is necessary as described above, the above-described auto idle signal path and the running junction are required. When the pilot passage is provided, a release pilot passage must be provided along with these passages, and there is a problem that a space for the passage becomes large and the booster circuit becomes enlarged.

  In view of the above circumstances, an object of the present invention is to provide a booster circuit for a construction machine and a supply unit for the booster circuit for a construction machine that can suppress the enlargement.

Means and effects for solving the problems

  A supply part of a booster circuit for a construction machine according to the present invention includes a first pump passage communicating with a first pump, a second pump passage communicating with a second pump, a tank passage communicating with a tank, and the tank passage Between the tank passage and the second pump passage. The first check valve is provided between the tank passage and the second pump passage. A second check valve having a flow from the second pump passage to the tank passage as a forward direction, and connected to a downstream side of the first check valve and a downstream side of the second check valve to remove excess pressure oil. A main relief valve that discharges to the tank passage, a normal pressure child valve that is connected to the back pressure chamber of the main relief valve and controls the relief pressure to normal pressure, and a relief that is connected to the back pressure chamber of the main relief valve Pressure A booster valve for controlling the booster to a pressure higher than the pressure, a back pressure switching valve for switching and connecting the back pressure chamber of the main relief valve to either the normal pressure slave valve or the booster slave valve, A boost pilot that is formed on one end of the back pressure switching valve and that introduces a boost signal for switching the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the booster valve. A release signal for switching the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the child valve for normal pressure, formed on the other end side of the chamber and the back pressure switching valve. An atmospheric pressure pilot chamber to be introduced, and provided in a booster circuit of a construction machine formed as a multiple valve in which a plurality of parts are continuously provided, and the first pump and the plurality of parts in the plurality of parts Pressure oil from the second pump is supplied A supply portion of the step-up circuit for a construction machine which is the body. And the 1st characteristic in the supply part body of the pressure | voltage rise circuit of the construction machine which concerns on this invention is equipped with the 1st block and 2nd block which are assembled | attached integrally, The said 1st block is equipped with the said 1st pump. A first pump port connected; the first pump passage communicating with the first pump port; a second pump port connected to the second pump; and the second pump communicating with the second pump port. A passage and a tank passage are formed, the first check valve and the second check valve are disposed in the first block, and the main relief valve is disposed between the first block and the second block. An orthogonal plane disposed between the first block and the second block between which the normal pressure child valve and the pressure raising child valve are orthogonal to the connecting direction of the multiple valves in the second block In The back pressure switching valve is disposed in the second block so as to be positioned closer to the first block than the normal pressure child valve and the booster child valve, and the back pressure switching valve It is arrange | positioned so that the spool of a valve may be located in the said orthogonal plane.

  According to this configuration, the supply unit of the booster circuit is configured by the first block and the second block that are assembled together, and the first check valve and the second check valve are arranged in the first block. A main relief valve connected downstream of both check valves is disposed between the first block and the second block between the first block and the second block, and the back pressure switching valve is the second block. Placed in the block. For this reason, the main relief valve is arranged between the first block and the second block to make the arrangement space of the main relief valve efficient so as to suppress dimensional constraints on other components, and the back pressure switching valve is also compact. Can be arranged together. Thereby, size reduction of a supply part body can be achieved. In addition, the normal pressure child valve and the booster child valve are arranged in the second block so as to lie in an orthogonal plane perpendicular to the direction in which the multiple valves are arranged, and the back pressure switching valve is always in the second block. It arrange | positions so that it may be located in the 1st block side rather than a pressure child valve and a pressure | voltage rise child valve, Furthermore, it arrange | positions so that the spool of a back pressure switching valve may be located in the above-mentioned orthogonal plane. For this reason, the normal pressure child valve and the booster child valve are arranged close to each other, and the back pressure switching valve can also be arranged close to the normal pressure child valve and the booster child valve in the same orthogonal plane. The body can be reduced in size in the thickness direction or in the spreading direction perpendicular to the thickness direction. Therefore, according to the structure of this invention, the supply part body of the booster circuit of the construction machine which can suppress enlargement can be obtained.

  A desirable second feature of the supply unit of the booster circuit of the construction machine according to the present invention is that the normal pressure subvalve and the booster subvalve are arranged in parallel to each other.

  According to this configuration, the normal pressure subvalve and the booster subvalve are arranged so as to be parallel to each other. Therefore, the normal pressure subvalve and the booster subvalve are further arranged closer to each other to reduce the size of the supply unit. Can be achieved.

  A desirable third feature of the supply unit of the booster circuit of the construction machine according to the present invention is that the first pump port and the second pump port are side surfaces parallel to the connecting direction in the first block. Opening at the same first side surface, the normal pressure subvalve and the booster subvalve are side surfaces parallel to the connecting direction in the second block, and the plane on which the first side surface is located That is, it is provided side by side on the second side surface that is orthogonal.

  According to this configuration, the normal pressure child valve and the booster child valve are arranged on the second side surface orthogonal to the plane on which the first side surface parallel to the connecting direction in which the first and second pump ports open is located. It is projecting at. For this reason, while suppressing interference with the positions of the first and second pump ports, the arrangement space of the normal pressure child valve and the pressure raising child valve can be made more efficient, and the supply body can be made more compact. it can.

  A booster circuit for a construction machine according to the present invention includes a first pump passage communicating with a first pump, a second pump passage communicating with a second pump, a tank passage communicating with a tank, the tank passage, A first check valve provided between the first pump passage and the forward flow from the first pump passage to the tank passage; and provided between the tank passage and the second pump passage; A second check valve having a forward flow from the second pump passage to the tank passage; and a downstream side of the first check valve and a downstream side of the second check valve to connect excess pressure oil to the tank. A main relief valve that discharges to the passage, a normal pressure child valve that is connected to the back pressure chamber of the main relief valve to control the relief pressure to normal pressure, and a relief pressure that is connected to the back pressure chamber of the main relief valve. Normal pressure A booster valve for controlling the booster to a higher pressure, a back pressure switching valve for switching and connecting the back pressure chamber of the main relief valve to either the normal pressure child valve or the booster valve, and the back A boosting pilot chamber formed on one end side of the pressure switching valve, into which a boosting signal is introduced for switching the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the booster valve. And a release signal that is formed on the other end side of the back pressure switching valve to switch the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the child valve for normal pressure. And a normal pressure pilot chamber. The first feature of the booster circuit for a construction machine according to the present invention is that an auto engine for controlling the rotational speed of the engine according to the operating state of each actuator by detecting the operation of each actuator of the construction machine. An auto idle signal path for generating an idle signal, a left travel pilot valve provided in conjunction with a left travel motor direction switching valve that controls supply of pressure oil to the left travel motor, and a pressure to the right travel motor A right travel pilot valve provided in conjunction with a right travel motor direction switching valve for controlling the supply of oil, and pressure oil from the first pump or the second pump other than the left travel motor and the right travel motor. Other actuators provided to interlock with other actuator directional control valves that control the supply of pressure oil to other actuators supplied with And the left travel pilot valve and the right travel pilot valve are arranged upstream of the auto idle signal path, and the other pilot valve for the actuator is the auto idle signal path. The left travel pilot valve and the right travel pilot valve are disposed downstream of the left travel pilot valve and the right travel pilot valve. Is switched to a communication state in which the auto idle signal passage is communicated, and is switched to a shutoff state in which the auto idle signal passage is shut off at the switching position, and pilot pressure oil from the auto idle signal passage is used as the normal pressure as the release signal. The atmospheric pilot chamber is adapted to be introduced into the pilot chamber. The left travel pilot valve and the right travel pilot valve are connected to the other idler pilot valve and the left travel pilot valve and the right travel pilot valve are switched. In addition, a supply passage capable of supplying pilot pressure oil to the normal pressure pilot chamber when in the position is further provided.

  According to this configuration, the normal pressure pilot chamber is connected to the auto idle signal passage so that the pilot pressure oil from the auto idle signal passage is introduced into the normal pressure pilot chamber as a release signal. Connected to the pilot valve. As a result, the release signal can be taken out using the auto idle signal path, so that a pilot for detecting the operation of another actuator to which pressure oil is supplied from the first pump or the second pump and releasing the pressure increase. The passage can be shared with the auto idle signal passage. Further, there is further provided a supply passage capable of supplying pilot pressure oil to the normal pressure pilot chamber when at least the left and right traveling pilot valve is in the switching position. For this reason, even when the left / right traveling pilot valve arranged on the upstream side of the auto idle signal passage is switched, a release signal for detecting the operation of other actuators and releasing the boost is supplied. It can be reliably taken out through the passage.

  A desirable second feature of the booster circuit of the construction machine according to the present invention is that by detecting that the left traveling motor, the right traveling motor, and one of the other actuators are activated, A traveling merging pilot passage for generating a traveling merging signal for switching a merging switching valve for merging the pressure oil supplied from the third pump with the pressure oil supplied from the first pump and the second pump; The left traveling pilot valve and the right traveling pilot valve are connected to the traveling merging pilot passage, and are switched to a tank communication state in which the traveling merging pilot passage communicates with the tank passage in a neutral position, and a switching position To switch to a tank shut-off state that shuts off the travel merging pilot passage and the tank passage. A lot valve, the right traveling pilot valve, and the other actuator pilot valve are connected in parallel to the traveling merging pilot passage, and the traveling merging pilot passage is connected to the traveling passage through the supply passage. A pilot passage check valve provided in a path extending upstream of the other actuator pilot valve in the auto idle signal passage and having a forward direction from the traveling confluence pilot passage to the auto idle signal passage; Furthermore, it is desirable to be provided.

  According to this configuration, the left and right traveling pilot valves and the other actuator pilot valves are connected in parallel to the traveling merging pilot passage, and from the traveling merging pilot passage to the auto idle signal passage through the supply passage. Pilot pressure oil is supplied on the upstream side of another actuator pilot valve. Thereby, even if the left and right traveling pilot valves are in the switching position, the pilot pressure oil is supplied from the traveling merging pilot passage to the other pilot valves for actuator. For this reason, the function of supplying pilot pressure oil for detecting the operation of other actuators and generating a release signal necessary for releasing the pressure increase can also be used as a traveling merge pilot passage. There is no need to provide a pilot passage. In addition to making the pilot path for the release signal common to the auto idle signal path, it is possible to make the traveling joint pilot path common.

  In addition, the supply part of the booster circuit for the construction machine according to another aspect of the present invention is the booster circuit for the construction machine according to the present invention, which is formed as a multiple valve in which a plurality of parts are continuously provided. A supply part of a booster circuit for a construction machine, which is provided in the one having the second feature, and is a part to which pressure oil from the first pump and the second pump is supplied in the plurality of parts. The first block and the second block are integrally assembled, and the first block includes a first pump port connected to the first pump, and the first block connected to the first pump port. A pump passage, a second pump port connected to the second pump, the second pump passage communicating with the second pump port, and the tank passage are formed, and the first check valve and the second pump valve are formed. The check valve is the first valve. And the main relief valve is disposed between the first block and the second block between the first block and the second block, and the normal pressure child valve and the pressure raising child. And the back pressure switching valve is disposed in the second block so as to be positioned on an orthogonal plane perpendicular to the connecting direction of the multiple valves. It is arranged so that it is located on the first block side relative to the child valve, the spool of the back pressure switching valve is located on the orthogonal plane, and the pilot passage check valve is located on the second block. It is arranged. The

  According to this configuration, since the pilot passage check valve is arranged in the second block in the forward direction from the traveling merging pilot passage to the auto idle signal passage through the supply passage, each pilot passage is arranged. Therefore, the space for arranging the pilot passage check valve can be made efficient so as to prevent the pilot passage check valve from being a dimensional constraint with respect to the space to be provided. Thereby, it can suppress that the part by which each pilot channel | path is arrange | positioned enlarges.

  Hereinafter, a booster circuit for a construction machine and a supply body of the booster circuit for a construction machine according to a preferred embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a hydraulic circuit diagram showing a booster circuit 1 (hereinafter simply referred to as a booster circuit 1) of a construction machine according to an embodiment of the present invention. A booster circuit 1 shown in FIG. 1 is provided in a construction machine (not shown), and is used as a hydraulic circuit of a construction machine including a left traveling motor, a right traveling motor, a turning motor, and various actuators for performing a cargo handling operation. Further, as shown in FIG. 2, the booster circuit 1 is formed as a multiple valve 2 in which a plurality of parts (20a to 20h, 20j, 20k, 20m, 20n, 21) are connected.

  As shown in FIG. 1, the booster circuit 1 includes a first pump 11 and a first system to which pressure oil is supplied from the first pump 11, a second pump 12 and a first system to which pressure oil is supplied from the second pump. The system includes two systems, a third pump 13 and a third system to which pressure oil is supplied from the third pump 13. The first system includes a right traveling motor direction switching valve 30 that controls the supply of pressure oil to the right traveling motor, a boom cylinder 18 and a boom direction switching valve 31 that controls the supply of pressure oil to the boom cylinder 18. A bucket cylinder 19 and a bucket direction switching valve 32 for controlling the supply of pressure oil to the bucket cylinder 19 are provided. The second system includes a left traveling motor direction switching valve 29 that controls the supply of pressure oil to the left traveling motor, an arm cylinder 17 and an arm direction switching valve 28 that controls the supply of pressure oil to the arm cylinder 17. A service direction switching valve 27 is provided. The third system includes an angle cylinder 14, an angle direction switching valve 22 that controls the supply of pressure oil to the angle cylinder 14, a dozer cylinder 15, and a direction for dozer that controls the supply of pressure oil to the dozer cylinder 15. There are a switching valve 23, a boom swing cylinder 16, a boom swing direction switching valve 24 that controls the supply of pressure oil to the boom swing cylinder 16, and a swing motor direction switching valve 25 that controls the supply of pressure oil to the swing motor. Is provided. Further, a merging switching valve 26 for joining the pressure oil supplied from the third pump 13 to the pressure oil supplied from the first pump 11 and the second pump 12 between the first system and the second system. Is provided.

  And in booster circuit 1, each pilot valve (22a-25a, 27a-32a) provided so that it may interlock with each direction switching valve (22-25, 27-32) may correspond to each direction switching valve (22-25). 27-32). For example, the left travel pilot valve 29a is the left travel motor direction switching valve 29, the right travel pilot valve 30a is the right travel motor pilot valve 30, the service pilot valve 27a is the service direction switching valve 27, the arm The pilot valve 28a is linked to the arm direction switching valve 28, the boom pilot valve 31a is linked to the boom direction switching valve 31, and the bucket pilot valve 32a is linked to the bucket direction switching valve 32. . The service pilot valve 27a, the arm pilot valve 28a, the boom pilot valve 31a, and the bucket pilot valve 32a constitute another actuator pilot valve in the present embodiment. That is, pressure oil to other actuators (service actuator, boom cylinder 18, bucket cylinder 19, arm cylinder 17) supplied with pressure oil from the first pump 11 or the second pump 12 other than the left travel motor and the right travel motor. The other actuator pilot valves (27a, 28a, 31a, 32a) are provided so as to be linked to the other actuator direction switching valves (27, 28, 31, 32) for controlling the supply of.

  In the booster circuit 1, as shown in FIG. 1, a first pump passage 34 that communicates with the first pump 11, a second pump passage 35 that communicates with the second pump 12, a tank passage 36 that communicates with the tank 33, The first check valve 37, the second check 38, the main relief valve 39, the atmospheric pressure child valve 40, the pressure raising child valve 41, the back pressure switching valve 42, the auto idle signal passage 43, the traveling merging pilot passage 44, and the supply passage 45 Etc. are also provided.

  The first check valve 37 is disposed between the tank passage 36 and the first pump passage 34 and is provided as a check valve that forwards the flow of pressure oil from the first pump 11 to the tank passage 36. It has been. The second check valve 38 is disposed between the tank passage 36 and the second pump passage 35, and is provided as a check valve that forwards the flow of pressure oil from the second pump passage 35 to the tank passage 36. It has been. The main relief valve 39 is connected to the downstream side of the first check valve 37 and the downstream side of the second check valve 38 (that is, between the first check valve 37 and the second check 38 and the tank passage 36). Is placed). The main relief valve 39 is provided as a relief valve that discharges excess pressure oil of the pressure oil supplied from the first pump 11 and the second pump 12 to the tank passage 36.

  The normal pressure child valve 40 is connected to the back pressure chamber of the main relief valve 39 and controls the relief pressure (pressure set as pressure of the pressure oil discharged as surplus pressure oil) to normal pressure (normal set pressure). It is provided as a valve. Further, the booster valve 41 is connected to the back pressure chamber of the main relief valve 39 to increase the relief pressure higher than the normal pressure (a pressure higher than the normal set pressure when only the traveling motor is driven). Set pressure).

  The back pressure switching valve 42 is configured to switch and connect the back pressure chamber of the main relief valve 39 to either the normal pressure child valve 40 or the pressure raising child valve 41. That is, the normal pressure child valve 40 and the booster child valve 41 are connected to the back pressure chamber of the main relief valve 39 via the back pressure switching valve 42. When the back pressure switching valve 42 is in the release position (normal position) 42a, the normal pressure child valve 40 is used. When the back pressure switching valve 42 is in the pressure raising position 42b, the pressure raising child valve 41 is used. Will be connected to the room. The back pressure switching valve 42 is provided with a boost pilot chamber 42c and a normal pressure pilot chamber 42d. The boost pilot chamber 42c is formed on one end side of the back pressure switching valve 42, and the back pressure switching valve 42 is brought to the boosting position 42b so as to connect the back pressure chamber of the main relief valve 39 and the booster valve 41. A boost signal as pilot pressure oil to be switched is introduced. The normal pressure pilot chamber 42d is formed on the other side of the back pressure switching valve 42, and the back pressure switching valve 42 is in a release position so as to connect the back pressure chamber of the main relief valve 39 and the normal pressure child valve 40. A release signal as pilot pressure oil for switching to 42a is introduced.

  The auto idle signal passage 43 detects the operation of each actuator of the construction machine, and generates an auto idle signal for controlling the rotational speed of the engine according to the operation state of each actuator. The auto idle signal is extracted from the port 49. The auto idle signal passage 43 is supplied with pilot pressure oil from a pilot pump (not shown), and each pilot valve of the third system (25a, 24a, 23a, 22a), left and right traveling pilot valves ( 29a, 30a), a boom pilot valve 31a, a bucket pilot valve 32a, an arm pilot valve 28a, and a service pilot valve 27a, and is connected to the tank passage 36. That is, the left travel pilot valve 29 a and the right travel pilot valve 30 a are disposed upstream of the auto idle signal passage 43, and the other pilot valves for actuators (31 a, 32 a, 28 a, 27 a) are provided in the auto idle signal passage 43. It is arranged downstream of the left travel pilot valve 29a and the right travel pilot valve 30a. Then, the normal pressure pilot chamber 42d is a passage between the left traveling pilot passage 29a and the right traveling pilot passage 30a with respect to the auto idle signal passage 43 and the pilot passages for other actuators (31a, 32a, 28a, 27a). 46 is connected. As a result, the pilot pressure oil from the auto idle signal passage 43 is introduced into the normal pressure pilot chamber 42d as the aforementioned release signal.

  The left traveling pilot valve 29a, the right traveling pilot valve 30a, and the other actuator pilot valves (31a, 32a, 28a, 27a) are all in neutral positions (29b, 30b, 31b, 32b, 28b, 27b), the auto idle signal path 43 is switched to a communicating state, and the auto idle signal path 43 is switched at the switching position (29c, 29d, 30c, 30d, 31c, 31d, 32c, 32d, 28c, 28d, 27c, 27d). It switches to the interruption state which interrupts.

  The pilot passage 44 for merging / running detects that the left traction motor, the right traction motor, and one of the other actuators (service actuator, arm cylinder 17, boom cylinder 18, bucket cylinder 19) are actuated. By doing so, a traveling merging signal for switching the merging switching valve 26 is generated. This traveling merging pilot passage 44 is connected to a passage for supplying pressure oil from the pilot pump to the pilot chamber of the merging switching valve 26, and also serves as a service pilot valve 27a, a left traveling pilot valve 29a, and a right traveling pilot. It is connected to the tank passage 36 via the valve 30a. Further, the left traveling pilot valve 29a is also connected to a passage 47 branched from the traveling merging pilot passage 44. The traveling merging pilot passage 44 is connected to other actuator pilot valves (31a, 32a, 28a, 27a). Is connected via a supply passage 45 and a passage 46 to the auto idle signal passage 43. Therefore, the left travel pilot valve 29a, the right travel pilot valve 30a, and the other actuator pilot valves (31a, 32a, 28a, 27a) are connected in parallel to the travel confluence pilot passage 44. It has become so.

  The left travel pilot valve 29a and the right travel pilot valve 30a are switched to the tank communication state where the travel merge pilot passage 44 communicates with the tank passage 36 at the neutral position (29b, 30b), and the switching position (29c, 29d, 30c, and 30d) are switched to a tank shut-off state in which the traveling / merging pilot passage 44 and the tank passage 36 are shut off.

  The supply passage 45 is connected to the atmospheric pressure pilot chamber 42d, and is connected to the traveling merging pilot passage 44 between the left traveling pilot valve 29a and the right traveling pilot valve 30a. When the left travel pilot valve 29a is in the switching position (29c, 29d), the travel confluence pilot passage 44 is kept in communication, and when the right travel pilot valve 30a is in the switch position (30c, 30d), The pilot passage 44 is blocked. For this reason, the supply passage 45 can supply pilot pressure oil to the atmospheric pressure pilot chamber 42d when at least the left traveling pilot valve 29a and the right traveling pilot valve 30a are in the switching position (29c, 29d, 30c, 30d). It has become.

  It should be noted that the path extending from the traveling merging pilot passage 44 to the upstream side of other actuator pilot valves (31a, 32a, 28a, 27a) in the auto idle signal passage 43 through the supply passage 45 and the passage 46 is reversed. A stop valve 48 is provided. The check valve 48 is provided such that the direction from the traveling merging pilot passage 44 to the auto idle signal passage 43 is a forward direction, and constitutes a pilot passage check valve in the present embodiment.

  Here, an operation of switching the relief pressure by the main relief valve 39 between the normal pressure and the boost in the boost circuit 1 described above will be described. First, in a state where all the directional control valves (22 to 25 and 27 to 32) are not operated, no boost signal is introduced into the boost pilot chamber 42c, and the auto idle signal passage 43 and the traveling confluence pilot are used. Both the passage 44 and the tank passage 36 communicate with each other, and no pilot pressure is applied to the normal pressure pilot chamber 42d. Therefore, the back pressure switching valve 42 is in the release position 42a due to the spring pressure acting in the normal pressure pilot chamber 42d, and the back pressure chamber of the main relief valve 39 is connected to the normal pressure sub valve 40. Yes. Thereby, in the booster circuit 1, the relief pressure of the main relief valve 39 is set to a normal pressure.

  On the other hand, when only the traveling motor is driven, that is, when the left and right traveling motor direction switching valves (29, 30) are operated to the second speed, a boost signal is introduced into the boost pilot chamber 42c. For this reason, the back pressure switching valve 42 is switched to the boosting position 42b against the spring pressure acting in the normal pressure pilot chamber 42d, and the back pressure chamber of the main relief valve 39 is connected to the boosting child valve 41. Become. Thereby, in the booster circuit 1, when only the traveling motor is driven, the relief pressure of the main relief valve 39 is set to be increased, and the driving torque of the traveling motor can be increased. At this time, since the traveling motor direction switching valve (29, 30) is switched to the switching position (29c or 29d, 30c or 30d), the pilot pressure oil from the upstream side of the auto idle signal passage 43 is always present. The pressure pilot chamber 42d is not introduced. Since the direction switching valves (22 to 25, 27, 28, 31, 32) other than the traveling motor direction switching valves (29, 30) are not operated, the pilot pressure from the traveling merging pilot passage 44 is determined. The oil is in a state of being released to the tank passage 36 via the supply passage 45, the passage 46 and the auto idle signal passage 43. For this reason, the release signal is not introduced into the atmospheric pressure pilot chamber 42d.

  Subsequently, when only at least one of the other actuators (service actuator, arm cylinder 17, boom cylinder 18, bucket cylinder 19) is driven from the state where only the traveling motor is driven as described above, that is, A case will be described in which at least one of the other directional control valves for actuators (27, 28, 31, 32) is driven from the state in which only the traveling motor directional control valves (29, 30) are operated. In this case, at least one of the other pilot valves for actuator (31a, 32a, 28a, 27a) is switched to the switching position (31c, 31d, 32c, 32d, 28c, 28d, 27c, 27d). The idle signal path 43 is blocked. Since the left and right traveling pilot valves (29a, 30a) are switched to the switching positions (29c, 29d, 30c, 30d), the pilot pressure oil from the traveling merge pilot passage 44 passes through the supply passage 45 and is at normal pressure. It is introduced into the pilot chamber 42d as a release signal. That is, since the downstream side of the auto idle signal passage 43 where the passage 46 is connected is blocked, the pressure oil from the supply passage 45 is introduced into the normal pressure pilot chamber 42d as a release signal. For this reason, the back pressure switching valve 42 is switched to the release position 42a against the boost signal by the release signal and the spring pressure acting in the normal pressure pilot chamber 42d, and the back pressure chamber of the main relief valve 39 is the normal pressure sub valve. 40 will be connected. Thus, in the booster circuit 1, when at least one of other actuators (service actuator, arm cylinder 17, boom cylinder 18, bucket cylinder 19) is driven in addition to the travel motor, the relief of the main relief valve 39 is driven. The pressure is set to normal pressure (the pressure increase state is released), and the driving torque of the travel motor can be returned to the normal setting.

  Next, the supply unit body 21 (hereinafter simply referred to as the supply unit body 21) of the booster circuit for a construction machine according to an embodiment of the present invention will be described. As described above, the booster circuit 1 shown in FIG. 1 has a multiple valve 2 in which a plurality of parts (20a to h, 20j, 20k, 20m, 20n, and 21) are continuously provided as shown in FIG. Is formed. The supply section 21 of the present embodiment is provided in the multiple valve 2 constituting the booster circuit 1, and pressure oil is supplied from the first pump 11 and the second pump 12 in the plurality of sections. It is comprised as a part to be made. In the description of the supply unit 21, the same reference numerals are used for the components described in the booster circuit 1, and the description is omitted as appropriate.

  FIG. 3 shows a plan view (FIG. 3 (a)) and a side view (FIG. 3 (b)) showing only the supply section 21 shown in FIG. As shown in FIGS. 2 and 3, the supply unit body 21 includes a first block 21 a and a second block 21 b that are assembled together. The first block 21 a and the second block 21 b are arranged so as to be aligned in a direction orthogonal to the direction in which the multiple valves 2 are provided.

  4 shows a cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 shows a cross-sectional view taken along the line V-V in FIG. As shown in FIGS. 3 to 5, the first block 21 a includes a first pump port 50 connected to the first pump 11, a first pump passage 34 communicating with the first pump port 50, and a second pump 12. A second pump port 51 to be connected, a second pump passage 35 communicating with the second pump port 51, a tank passage 36, and the like are formed. The first pump port 50 and the second pump port 51 open at the same first side surface 52 that is a side surface parallel to the connecting direction of the multiple valve 2 in the first block 21a. A first check valve 37 and a second check valve 38 are arranged in the first block 21a. Moreover, the main relief valve 39 is arrange | positioned over the 1st block 21a and the 2nd block 21b between the 1st block 21a and the 2nd block 21b. The check valve 48 is disposed in the second block 21b.

  Further, as shown in FIGS. 3 to 5, the atmospheric pressure child valve 40 and the pressure raising child valve 41 are arranged so as to be positioned on an orthogonal plane orthogonal to the connecting direction of the multiple valves 2 in the second block. (That is, the cross section shown in FIG. 5 is located in this orthogonal plane). The normal pressure child valve 40 and the pressure raising child valve 41 are disposed so as to be parallel to each other, and are side surfaces parallel to the connecting direction of the multiple valves 2 in the second block 21b and the first side valve. The second side surface 53 that is orthogonal to the plane on which the side surface 52 is located protrudes side by side. Further, as well shown in FIG. 5, the back pressure switching valve 42 is disposed in the second block 21b so as to be positioned closer to the first block 21a side than the normal pressure child valve 40 and the pressure raising child valve 41. The spool 54 of the back pressure switching valve 42 is arranged so as to be positioned on the above-described orthogonal plane (plane on which the cross section shown in FIG. 5 is located).

  As described above, according to the supply unit body 21 of the present embodiment, the supply unit body 21 includes the first block 21a and the second block 21b that are assembled together, and the first check valve 37 and the first block 21b. Two check valves 38 are arranged in the first block 21a. A main relief valve 39 connected to the downstream side of both check valves (37, 38) extends between the first block 21a and the second block 21b between the first block 21a and the second block 21b. The back pressure switching valve 42 is disposed in the second block 21b. For this reason, the main relief valve 39 is arranged between the first block 21a and the second block 21b to make the arrangement space of the main relief valve 39 efficient so as to suppress the dimensional constraints on other components, and the back pressure The switching valves 42 can also be arranged in a compact manner. Thereby, size reduction of the supply part body 21 can be achieved.

  In addition, the normal pressure child valve 40 and the pressure raising child valve 41 are arranged in the second block 21b so as to be positioned in an orthogonal plane orthogonal to the direction in which the multiple valves 2 are arranged, and the back pressure switching valve 42 is provided. The second block 21b is disposed so as to be located closer to the first block 21a than the normal pressure subvalve 40 and the booster subvalve 41, and further, the spool 54 of the back pressure switching valve 42 is positioned in the aforementioned orthogonal plane. Is arranged. Therefore, the normal pressure subvalve 40 and the booster subvalve 41 are arranged close to each other, and the back pressure switching valve 42 is also arranged close to the normal pressure subvalve 40 and the booster subvalve 41 on the same orthogonal plane. It is possible to reduce the size of the supply body 21 in the thickness direction or in the spreading direction perpendicular to the thickness direction.

  Therefore, according to this embodiment, the supply part body of the booster circuit of the construction machine which can suppress enlargement can be obtained.

  Further, according to the supply section 21, the normal pressure subvalve 40 and the booster subvalve 41 are arranged so as to be parallel to each other. It can arrange | position and can attain size reduction of a supply part body.

  Moreover, according to the supply part 21, the 2nd side surface orthogonal to the plane in which the 1st side surface 52 parallel to the connection direction of the multiple valve 2 which the 1st pump port 50 and the 2nd pump port 51 open is located is located. In FIG. 53, the normal pressure child valve 40 and the pressure raising child valve 41 are juxtaposed. For this reason, while suppressing interference with the position of the 1st pump port 50 and the 2nd pump port 51, the arrangement space of the child valve 40 for normal pressure and the child valve 41 for pressure | voltage rise can be made efficient, and supply part 21 of Further downsizing can be achieved.

  Further, according to the supply section 21, the check valve 48 having the forward direction from the traveling merge pilot passage 44 to the auto idle signal passage 43 through the supply passage 45 is disposed in the second block 21b. Therefore, the arrangement space of the check valve 48 can be made efficient so as to suppress the check valve 48 from being a dimensional constraint with respect to the space in which each pilot passage 55 (see FIGS. 4 and 5) is arranged. Thereby, it can suppress that the part by which each pilot channel | path 55 is arrange | positioned enlarges.

  Further, according to the booster circuit 1 of the present embodiment, the normal pressure pilot chamber 42d is connected to the auto idle signal passage 43 so that the pilot pressure oil from the auto idle signal passage 43 is introduced into the normal pressure pilot chamber 42d as a release signal. On the other hand, the left and right traveling pilot valves (29a, 30a) and other actuator pilot valves (31a, 32a, 27a, 28a) are connected. As a result, the release signal can be taken out using the auto idle signal passage 43, so that other actuators (service actuator, arm cylinder 17, boom cylinder) to which pressure oil is supplied from the first pump 11 or the second pump 12 are used. 18, the pilot passage for detecting the operation of the bucket cylinder 19) and releasing the pressure increase can be shared with the auto idle signal passage 43.

  Further, there is further provided a supply passage 45 capable of supplying pilot pressure oil to the atmospheric pressure pilot chamber 42d when at least the left and right traveling pilot valves (29a, 30a) are in the switching position (29c, 29d, 30c, 30d). . For this reason, even when the left and right traveling pilot valves (29a, 30a) arranged on the upstream side of the auto idle signal passage 43 are switched, other actuators (service actuator, arm cylinder 17, boom cylinder 18) are switched. The release signal for detecting the operation of the bucket cylinder 19) and releasing the pressure increase can be reliably taken out through the supply passage 45.

  According to the booster circuit 1, the left and right traveling pilot valves (29a, 30a) and the other actuator pilot valves (31a, 32a, 28a, 27a) are connected in parallel to the traveling merging pilot passage 44 and travel. Pilot pressure oil is supplied from the merging pilot passage 44 to the auto idle signal passage 43 through the supply passage 45 on the upstream side of the other pilot valves (31a, 32a, 28a, 27a). As a result, even if the left and right traveling pilot valves (29a, 30a) are in the switching position (29c, 29d, 30c, 30d), the other pilot valves (31a, 32a, 28a, 27a) are connected from the traveling merging pilot passage 44. ) Is supplied with pilot pressure oil. For this reason, the function of supplying pilot pressure oil for detecting the operation of other actuators (service actuator, arm cylinder 17, boom cylinder 18, bucket cylinder 19) and generating a release signal necessary to release the pressure increase Can also serve as the traveling merge pilot passage 44, and a separate release signal pilot passage need not be provided. In addition to the common use of the release signal pilot passage in the auto idle signal passage 43, the traveling confluence pilot passage 44 can also be used in common.

  In the present embodiment, a travel merging signal for switching the merging switching valve 26 for merging the pressure oil supplied from the third pump 13 with the pressure oil supplied from the first pump 11 and the second pump 12 is generated. Although a case where the pilot path for the release signal is shared with the traveling merge pilot path 44 has been described as an example, this need not be the case. For example, when the left and right traveling motor and at least one of other actuators (service actuator, arm cylinder 17, boom cylinder 18, bucket cylinder 19) are driven, the pressure oil from the first pump 11 and the second pump 12 are driven. Even in a booster circuit provided with a merging pilot passage for generating a merging signal for switching a merging valve for merging pressure oil from the merging pilot passage, a pilot passage for a release signal is made common to the merging pilot passage. Good. The pressure introduced into the boost pilot chamber 42c is also used as a signal for switching the traveling unit to the second speed. However, a signal may be separately generated and applied. A spring may be used instead of the boost pilot chamber 42c.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims.

1 is a hydraulic circuit diagram showing a booster circuit of a construction machine according to an embodiment of the present invention. It is a top view which shows the multiple valve which comprises the booster circuit shown in FIG. It is the top view which took out and showed only the supply part body shown in FIG. 2, and its side view. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Booster circuit 2 of construction machine 2 Multiple valve 11 1st pump 12 2nd pump 34 1st pump passage 35 2nd pump passage 36 Tank passage 37 1st check valve 38 2nd check valve 39 Main relief valve 40 Normal pressure child valve 41 Booster valve 42 Back pressure switching valve 42c Booster pilot chamber 42d Normal pressure pilot chamber 21 Supply part 21a of the booster circuit of the construction machine First block 21b Second block 50 First pump port 51 Second pump port

Claims (6)

A first pump passage communicating with the first pump;
A second pump passage communicating with the second pump;
A tank passage communicating with the tank;
A first check valve provided between the tank passage and the first pump passage, wherein the flow from the first pump passage to the tank passage is a forward direction;
A second check valve provided between the tank passage and the second pump passage, wherein the flow from the second pump passage to the tank passage is a forward direction;
A main relief valve connected to the downstream side of the first check valve and the downstream side of the second check valve to discharge excess pressure oil to the tank passage;
A sub-valve for normal pressure connected to the back pressure chamber of the main relief valve to control the relief pressure to normal pressure;
A booster valve that is connected to the back pressure chamber of the main relief valve and controls the relief pressure to be higher than the normal pressure;
A back pressure switching valve for switching and connecting the back pressure chamber of the main relief valve to either the normal pressure sub-valve or the boost sub-valve;
Booster that is formed on one end side of the back pressure switching valve and introduces a boost signal for switching the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the booster valve. A pilot room,
A release signal, which is formed on the other end side of the back pressure switching valve, is used to switch the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the child valve for normal pressure. An atmospheric pilot room,
Provided with a booster circuit of a construction machine formed as a multiple valve in which a plurality of parts are provided in series, and pressure oil from the first pump and the second pump in the plurality of parts is supplied A supply unit for a booster circuit of a construction machine,
A first block and a second block that are assembled together;
The first block includes a first pump port connected to the first pump, the first pump passage communicating with the first pump port, a second pump port connected to the second pump, The second pump passage communicating with the second pump port and the tank passage are formed;
The first check valve and the second check valve are arranged in the first block;
The main relief valve is disposed between the first block and the second block between the first block and the second block;
The normal pressure subvalve and the pressurization subvalve are arranged so as to be located in an orthogonal plane orthogonal to the connecting direction of the multiple valves in the second block,
The back pressure switching valve is disposed in the second block so as to be positioned closer to the first block than the normal pressure child valve and the boosting child valve, and the spool of the back pressure switching valve is in the orthogonal plane. It is arrange | positioned so that it may be located in the supply part of the booster circuit of a construction machine characterized by the above-mentioned.   2. The supply part of a booster circuit for a construction machine according to claim 1, wherein the sub-valve for normal pressure and the sub-valve for boost are disposed so as to be parallel to each other. The first pump port and the second pump port open on the same first side surface that is a side surface parallel to the connecting direction in the first block,
The normal pressure subvalve and the booster subvalve protrude side by side on a second side surface that is a side surface parallel to the connecting direction in the second block and is orthogonal to a plane on which the first side surface is located. The supply part of the booster circuit of the construction machine according to claim 1 or 2, wherein the supply part is provided. A first pump passage communicating with the first pump;
A second pump passage communicating with the second pump;
A tank passage communicating with the tank;
A first check valve provided between the tank passage and the first pump passage, wherein the flow from the first pump passage to the tank passage is a forward direction;
A second check valve provided between the tank passage and the second pump passage, wherein the flow from the second pump passage to the tank passage is a forward direction;
A main relief valve connected to the downstream side of the first check valve and the downstream side of the second check valve to discharge excess pressure oil to the tank passage;
A sub-valve for normal pressure connected to the back pressure chamber of the main relief valve to control the relief pressure to normal pressure;
A booster valve that is connected to the back pressure chamber of the main relief valve and controls the relief pressure to be higher than the normal pressure;
A back pressure switching valve for switching and connecting the back pressure chamber of the main relief valve to either the normal pressure sub-valve or the boost sub-valve;
Booster that is formed on one end side of the back pressure switching valve and introduces a boost signal for switching the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the booster valve. A pilot room,
A release signal, which is formed on the other end side of the back pressure switching valve, is used to switch the back pressure switching valve so as to connect the back pressure chamber of the main relief valve and the child valve for normal pressure. An atmospheric pilot room,
A booster circuit for a construction machine comprising:
By detecting the operation of each actuator of the construction machine, an auto idle signal path that generates an auto idle signal for controlling the rotational speed of the engine according to the operating state of each actuator;
A left travel pilot valve provided in conjunction with a left travel motor direction switching valve for controlling the supply of pressure oil to the left travel motor;
A pilot valve for right travel provided to operate in conjunction with a direction switching valve for right travel motor that controls supply of pressure oil to the right travel motor;
Interlocking with other actuator directional control valves that control the supply of pressure oil to other actuators supplied with pressure oil from the first pump or the second pump other than the left travel motor and the right travel motor. A pilot valve for another actuator provided in
Further comprising
The left travel pilot valve and the right travel pilot valve are disposed upstream of the auto idle signal path, and the other actuator pilot valves are the left travel pilot valve and the right travel in the auto idle signal path. Is located downstream of the pilot valve for
The left travel pilot valve, the right travel pilot valve, and the other pilot valve for the other actuator are all switched to a communication state in which the auto idle signal passage is communicated at the neutral position, and the auto idle signal at the switching position. Switch to the blocking state to block the signal path,
The normal pressure pilot chamber is connected to the left idle pilot passage and the right pilot valve so that pilot pressure oil from the auto idle signal passage is introduced into the normal pressure pilot chamber as the release signal. Connected between the pilot valve for traveling and the pilot valve for the other actuator,
A booster for a construction machine, further comprising a supply passage capable of supplying pilot pressure oil to the atmospheric pressure pilot chamber when at least the left travel pilot valve and the right travel pilot valve are in a switching position. circuit. A booster circuit for a construction machine according to claim 4,
By detecting that the left traveling motor, the right traveling motor, and one of the other actuators are operated, the pressure oil supplied from the third pump is supplied to the first pump and the first pump. A traveling merging pilot passage for generating a traveling merging signal for switching a merging switching valve for merging with the pressure oil supplied from the two pumps;
The left traveling pilot valve and the right traveling pilot valve are connected to the traveling merging pilot passage, and are switched to a tank communication state in which the traveling merging pilot passage communicates with the tank passage in a neutral position, and a switching position To switch to a tank shut-off state that shuts off the traveling merge pilot passage and the tank passage,
The left travel pilot valve, the right travel pilot valve, and the other actuator pilot valve are connected in parallel to the travel confluence pilot passage;
Provided in a path from the traveling merge pilot path to the upstream side of the other actuator pilot valve in the auto idle signal path via the supply path, and from the traveling merge pilot path to the auto idle signal path A booster circuit for a construction machine, further comprising a pilot passage check valve having a forward direction as a forward direction. The pressure from the first pump and the second pump in the plurality of parts is provided in the booster circuit of the construction machine according to claim 5 formed as a multiple valve in which a plurality of parts are continuously provided. A supply part of a booster circuit of a construction machine, which is a part to which oil is supplied,
A first block and a second block that are assembled together;
The first block includes a first pump port connected to the first pump, the first pump passage communicating with the first pump port, a second pump port connected to the second pump, The second pump passage communicating with the second pump port and the tank passage are formed;
The first check valve and the second check valve are arranged in the first block;
The main relief valve is disposed between the first block and the second block between the first block and the second block;
The normal pressure subvalve and the pressurization subvalve are arranged so as to be located in an orthogonal plane orthogonal to the connecting direction of the multiple valves in the second block,
The back pressure switching valve is disposed in the second block so as to be positioned closer to the first block than the normal pressure child valve and the boosting child valve, and the spool of the back pressure switching valve is in the orthogonal plane. Arranged to be located at
A supply part of a booster circuit for a construction machine, wherein the pilot passage check valve is disposed in the second block.

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