Multi-control valve

Abstract

A housing (2) of a multiple control valve (1) is provided with a boom parallel passage (41), a boom retract feed passage (43), a boom extend feed passage (44), a boom parallel passage (51), a boom raising feed passage (54), and a boom lowering feed passage (53). In addition, the housing (2) is provided with a slide hole (23), a head side passage (62) which reaches the slide hole (23) from the boom raising feed passage (54) after branching, a rod side passage (61) which reaches the slide hole (23) from the boom lowering feed passage (53) after branching, and a regeneration passage (64) from the slide hole (23) to the boom parallel passage (41). A boom sub valve spool (6) which is either one of a boom raising regeneration valve spool (6A) and a boom lowering regeneration valve spool (6B) is inserted in the slide hole (23).

Description

Technical Field

[0001] This invention relates to multiple control valves for hydraulic excavators. Background Technology

[0002] In the past, hydraulic excavators have used multi-control valves that include multiple valve cores (see, for example, Patent Document 1). These multi-control valves are connected to a hydraulic pump, a tank, and multiple hydraulic actuators, and together they form a hydraulic circuit.

[0003] For example, in a hydraulic circuit that supplies working fluid from a pump to the boom cylinder and stick cylinder, multiple control valves include boom drive valve spools and stick drive valve spools, as well as housings that slidably hold the boom drive valve spools and stick drive valve spools.

[0004] The boom drive valve core opens and closes the boom parallel passage, boom lifting supply passage, and boom lowering supply passage located in the housing. That is, by moving the boom drive valve core, the boom parallel passage, which branches off from the pump passage located in the housing, can be connected to either the boom lifting supply passage or the boom lowering supply passage.

[0005] The boom drive valve core opens and closes the boom parallel passage, boom retraction supply passage, and boom extension supply passage located in the housing. That is, by moving the boom drive valve core, the boom parallel passage branching off from the pump passage located in the housing can be connected to either the boom retraction supply passage or the boom extension supply passage.

[0006] The hydraulic circuit of a hydraulic excavator is sometimes configured to supply the working fluid flowing in the boom lifting supply line (i.e., the working fluid discharged from the head side of the boom cylinder) to the boom lowering supply line (i.e., the rod side of the boom cylinder) during the boom lowering operation (i.e., when the boom is lowered) (so-called boom regeneration) (see, for example, Patent Document 2).

[0007] Furthermore, the hydraulic circuit of a hydraulic excavator is sometimes configured to supply working fluid discharged from the head side of the boom cylinder to the stick cylinder when boom lowering and stick operation are performed simultaneously (so-called boom regeneration) (see, for example, Patent Document 3).

[0008] Existing technical documents:

[0009] Patent documents:

[0010] Patent Document 1: Japanese Patent Application Publication No. 2015-78713;

[0011] Patent Document 2: Japanese Patent Application Publication No. 2010-286074;

[0012] Patent document 3: Japanese Patent Application Publication No. 2018-105333. Summary of the Invention

[0013] The problem the invention aims to solve:

[0014] Previously, the multi-control valves used in the hydraulic circuit for boom regeneration and those used in the hydraulic circuit for boom return were completely different. Therefore, in order to change the hydraulic circuit for boom regeneration to that for boom return, or vice versa, the multi-control valve itself needs to be replaced.

[0015] Therefore, the object of the present invention is to provide a multi-control valve that can correspond to both the hydraulic circuit for boom regeneration and the hydraulic circuit for boom return, even without replacing the multi-control valve itself, especially the housing of the multi-control valve.

[0016] Solution methods:

[0017] To solve the aforementioned problems, the present invention provides a multi-control valve for hydraulic excavators, characterized in that it comprises: a stick drive valve core, a boom drive valve core, a boom auxiliary valve core, and a housing that slidably holds the stick drive valve core, the boom drive valve core, and the boom auxiliary valve core; the housing is provided with: a stick parallel passage, a stick retraction supply passage, and a stick extension supply passage opened and closed by the stick drive valve core; a boom parallel passage, a boom lifting supply passage, and a boom lowering supply passage opened and closed by the boom drive valve core; a sliding hole into which the boom auxiliary valve core is inserted; and a sliding hole for the boom lifting... The supply passage branches off to the head-side passage of the sliding hole; the boom-falling supply passage branches off to the rod-side passage of the sliding hole; and the regeneration passage branches off from the sliding hole to the stick parallel passage; the boom auxiliary valve core is either a boom regeneration valve core or a boom regeneration valve core, the boom regeneration valve core moves between a neutral position that blocks the head-side passage and the rod-side passage and a regeneration position that connects the head-side passage and the rod-side passage, and the boom regeneration valve core moves between a neutral position that blocks the head-side passage and the regeneration passage and a regeneration position that connects the head-side passage and the regeneration passage.

[0018] Additionally, "boom regeneration" refers to the supply of working fluid discharged from the head side of the boom cylinder to the stick side of the boom cylinder during boom lowering operations, while "boom recovery" refers to the supply of working fluid discharged from the head side of the boom cylinder to the stick cylinder during boom lowering operations and stick operations simultaneously.

[0019] Based on the above structure, boom regeneration can be achieved by inserting a boom regeneration valve core into the sliding hole, and boom retraction can be achieved by inserting a boom retraction valve core into the sliding hole. Therefore, even without replacing the multi-control valve itself, and without replacing the housing, only the boom auxiliary valve core needs to be replaced to achieve both the hydraulic circuit for boom regeneration and the hydraulic circuit for boom retraction.

[0020] Invention effects:

[0021] According to the present invention, a multi-control valve is provided that can correspond to both the hydraulic circuit for boom regeneration and the hydraulic circuit for boom return, even without replacing the multi-control valve itself. Attached Figure Description

[0022] Figure 1 This is a schematic structural diagram of a multi-control valve according to an embodiment of the present invention, showing the hydraulic circuit when using a valve core for boom regeneration;

[0023] Figure 2 This is a schematic diagram of the multi-control valve, showing the hydraulic circuit when using the boom regeneration valve core;

[0024] Figure 3 This is a side view of a hydraulic excavator;

[0025] Figure 4 This is a cross-sectional view of a multi-control valve when using a valve core for boom regeneration;

[0026] Figure 5 This is a cross-sectional view of a multi-control valve when using a boom regeneration valve core. Detailed Implementation

[0027] Figure 1 and Figure 2 A multi-control valve 1 according to an embodiment of the present invention is shown. The multi-control valve 1 is used for... Figure 3 The hydraulic excavator 10 shown has a multi-control valve 1 connected to a hydraulic pump 17, a tank 18, and multiple hydraulic actuators, forming a hydraulic circuit together. Additionally, Figure 1 The hydraulic circuit is shown when the boom regeneration valve core 6A (described later) is used as the boom auxiliary valve core 6 (described later). Figure 2 The hydraulic circuit is shown when the boom regeneration valve core 6B, described later, is used as the boom auxiliary valve core 6.

[0028] Figure 3 The hydraulic excavator 10 shown is self-propelled and includes a traveling body 11. Furthermore, the hydraulic excavator 10 includes a rotating body 12 rotatably supported on the traveling body 11 and a boom that pitches relative to the rotating body 12. A stick is swayably connected to the tip of the boom, and a bucket is swayably connected to the tip of the stick. A cabin 16 with a driver's seat is provided on the rotating body 12. Alternatively, the hydraulic excavator 10 may not be self-propelled.

[0029] The hydraulic excavator 10 includes a boom cylinder 13 for tilting the boom, a stick cylinder 14 for swinging the stick, and a bucket cylinder 15 for swinging the bucket as hydraulic actuators. Furthermore, although not shown in the figures, the hydraulic excavator 10 also includes a left travel motor and a right travel motor for driving the left and right tracks of the traveling body 11, and a rotary motor for rotating the rotating body 12 as hydraulic actuators.

[0030] Other, Figure 1 and Figure 2 For the sake of simplicity in the accompanying drawings, hydraulic actuators other than the boom cylinder 13 and stick cylinder 14 are omitted. Furthermore, the following description of the structures used to drive parts other than the boom and stick is also omitted.

[0031] The multi-control valve 1 includes a boom drive valve core 5 and a stick drive valve core 4, and a housing 2 that slidably holds the boom drive valve core 5 and the stick drive valve core 4. Although the cross-sectional view is omitted, the housing 2 is provided with a first sliding hole 21 for inserting the boom drive valve core 5 and a second sliding hole 22 for inserting the stick drive valve core 4.

[0032] The housing 2 has a pump port 2a and a tank port 2b. The pump port 2a is connected to the hydraulic pump 17 via a pipe, and the tank port 2b is connected to the tank 18 via a pipe.

[0033] In addition, the housing 2 has a pair of boom feed ports 2d and a pair of stick feed ports 2c. The boom feed ports 2d are connected to the boom cylinder 13 via piping, and the stick feed ports 2c are connected to the stick cylinder 14 via piping.

[0034] In this embodiment, the multi-control valve 1 also includes an unload spool 7. The unload spool 7 is as follows: Figure 4 and Figure 5 As shown, it is inserted into the third sliding hole 23 located in the housing 2. That is, the unloading valve core 7 is slidably held in the housing 2.

[0035] like Figure 1 and Figure 2 As shown, the housing 2 is provided with a pump passage 31 from the pump port 2a to the third sliding hole 23 and a tank passage 32 from the tank port 2b to the third sliding hole 23.

[0036] The boom parallel passage 51 and the stick parallel passage 41 branch off from the pump passage 31. The boom parallel passage 51 abuts against the first sliding hole 21, and the stick parallel passage 41 abuts against the second sliding hole 22. Furthermore, the housing 2 is provided with a boom tank passage 52 from the first sliding hole 21 to the tank passage 32 and a stick tank passage 42 from the second sliding hole 22 to the tank passage 32.

[0037] In addition, the housing 2 is provided with a boom lifting supply passage 54 and a boom lowering supply passage 53 from the boom feeding port 2d to the first sliding hole 21, and a stick retraction supply passage 43 and a stick extension supply passage 44 from the stick feeding port 2c to the second sliding hole 22.

[0038] The boom drive valve 5 opens and closes the boom parallel passage 51, the boom tank passage 52, the boom lifting supply passage 54, and the boom lowering supply passage 53. Specifically, the boom drive valve 5 moves between the neutral position and the boom lifting and boom lowering positions.

[0039] In the neutral position, the boom drive valve 5 closes the boom parallel passage 51, the boom tank passage 52, the boom lifting supply passage 54, and the boom lowering supply passage 53. In the boom lifting position, the boom drive valve 5 connects the boom parallel passage 51 with the boom lifting supply passage 54 and connects the boom lowering supply passage 53 with the boom tank passage 52. In the boom lowering position, the boom drive valve connects the boom parallel passage 51 with the boom lowering supply passage 53 and closes the boom lifting supply passage 54 and the boom tank passage 52.

[0040] In this embodiment, the boom drive valve core 5 is driven by pilot pressure. However, the boom drive valve core 5 can also be connected to an electric actuator and driven by that electric actuator.

[0041] More specifically, one end face and the other end face of the boom drive valve core 5 face the first pilot chamber 5a and the second pilot chamber 5b, respectively. When the pilot pressure introduced into the first pilot chamber 5a increases, the boom drive valve core 5 moves from the neutral position to the boom raising position, and when the pilot pressure introduced into the second pilot chamber 5b increases, it moves from the neutral position to the boom lowering position. Furthermore, the opening area between the boom parallel passage 51 and the boom raising supply passage 54 at the boom raising position increases with the higher the pilot pressure introduced into the first pilot chamber 5a, and the opening area between the boom parallel passage 51 and the boom lowering supply passage 53 at the boom lowering position increases with the higher the pilot pressure introduced into the second pilot chamber 5b.

[0042] The boom drive valve core 4 opens and closes the boom parallel passage 41, the boom tank passage 42, the boom retraction supply passage 43, and the boom extension supply passage 44. Specifically, the boom drive valve core 4 moves between the neutral position, the boom retraction position, and the boom extension position.

[0043] In the neutral position, the boom drive valve 4 closes the boom parallel passage 41, the boom tank passage 42, the boom retraction supply passage 43, and the boom extension supply passage 44. In the boom retraction position, the boom drive valve 4 connects the boom parallel passage 41 with the boom retraction supply passage 43 and connects the boom extension supply passage 44 with the boom tank passage 42. In the boom extension position, the boom drive valve 4 connects the boom parallel passage 41 with the boom extension supply passage 44 and connects the boom retraction supply passage 43 with the boom tank passage 42.

[0044] In this embodiment, the boom drive valve core 4 is driven by pilot pressure. However, the boom drive valve core 4 can also be connected to an electric actuator and driven by that electric actuator.

[0045] More specifically, one end face and the other end face of the boom drive valve core 4 face the first pilot chamber 4a and the second pilot chamber 4b, respectively. When the pilot pressure introduced into the first pilot chamber 4a increases, the boom drive valve core 4 moves from the neutral position to the boom retraction position; when the pilot pressure introduced into the second pilot chamber 4b increases, it moves from the neutral position to the boom extension position. Furthermore, the opening area between the boom parallel passage 41 and the boom retraction supply passage 43 at the boom retraction position increases with the higher the pilot pressure introduced into the first pilot chamber 4a; similarly, the opening area between the boom parallel passage 41 and the boom extension supply passage 44 at the boom extension position increases with the higher the pilot pressure introduced into the second pilot chamber 4b.

[0046] The unloading valve core 7 is used to adjust the opening area between the pump passage 31 and the tank passage 32. The unloading valve core 7 moves between a neutral position that blocks the connection between the pump passage 31 and the tank passage 32 and an open position that connects the pump passage 31 and the tank passage 32.

[0047] In this embodiment, the unloading valve core 7 is driven by pilot pressure. However, the unloading valve core 7 can also be connected to an electric actuator and driven by that electric actuator.

[0048] More specifically, such as Figure 4 and Figure 5 As shown, one end face of the unloading valve core 7 faces the pilot chamber 70. When the pilot pressure entering the pilot chamber 70 increases, the unloading valve core 7 moves from the neutral position to the open position. Furthermore, the opening area between the pump passage 31 and the tank passage 32 increases with the higher the pilot pressure entering the pilot chamber 70.

[0049] Other, Figure 4 and Figure 5 In this configuration, a pilot chamber 70 is formed by a container-shaped cover 37 installed on the housing 2. Furthermore, a spring 38 is disposed within the cover 37 to maintain the unloading valve core 7 in a neutral position.

[0050] Furthermore, in this embodiment, the boom auxiliary valve core 6 is inserted into the third sliding hole 23. That is, the boom auxiliary valve core 6 is slidably held in the housing 2. The boom auxiliary valve core 6 is Figure 1 and Figure 4 The boom regeneration valve core 6A shown is... Figure 2 and Figure 5 Any one of the boom regeneration valve cores 6B shown.

[0051] The housing 2 is provided with a head-side passage 62 that branches off from the boom lifting supply passage 54 and reaches the third sliding hole 23, and a rod-side passage 61 that branches off from the boom lowering supply passage 53 and reaches the third sliding hole 23. In addition, the housing 2 is provided with a regeneration / recovery tank passage 63 that runs from the third sliding hole 23 to the tank passage 32, and a recovery passage 64 that runs from the third sliding hole 23 to the parallel passage 41 for the boom.

[0052] Additionally, in the parallel passage 41 for the boom, a check valve 45 is provided near the upstream side (i.e., the pump side) at the location where it connects to the regeneration passage 64. The check valve 45 allows flow from the pump passage 31 toward the second sliding hole 22 but prohibits its reverse flow.

[0053] Valve core 6A for boom regeneration, such as Figure 1 As shown, the device moves between a neutral position that blocks the head-side passage 62 and the rod-side passage 61 and a regeneration position that connects the head-side passage 62 and the rod-side passage 61. In this embodiment, in the regeneration position, the head-side passage 62 is also connected to the regeneration / regeneration tank passage 63.

[0054] In this embodiment, the boom regeneration valve 6A is driven by pilot pressure. However, the boom regeneration valve 6A can also be connected to an electric actuator and driven by that electric actuator.

[0055] More specifically, such as Figure 4 As shown, one end face of the boom regeneration valve core 6A faces the pilot chamber 60. When the pilot pressure in the pilot chamber 60 increases, the boom regeneration valve core 6A moves from the neutral position to the regeneration position. Furthermore, the opening area between the head-side passage 62 and the rod-side passage 61 increases with the higher the pilot pressure in the pilot chamber 60.

[0056] Other, Figure 4 In this configuration, a pilot chamber 60 is formed by a container-shaped cover 35 installed on the housing 2. Furthermore, a spring 36 is disposed within the cover 35 to maintain the boom regeneration valve core 6A in a neutral position.

[0057] As mentioned above, the boom drive valve core 5 closes the boom tank passage 52 when the boom is in the lower position. Therefore, when using the boom regeneration valve core 6A, the boom regeneration valve core 6A moves in the same way as the boom drive valve core 5 when the boom is in the lower position.

[0058] Other, Figure 4 In the middle, a check valve 9 is provided on the rod-side passage 61. Figure 1 (omitted). The check valve 9 allows flow from the head-side passage 62 toward the rod-side passage 61 but prevents its reverse flow. Specifically, the check valve 9 includes a poppet 91 slidably held in the housing 2, a cover 93 fixed to the housing 2, and a spring 92 disposed between the poppet 91 and the cover 93.

[0059] 6B valve core for boom regeneration Figure 2 As shown, it moves between a neutral position that blocks the head-side passage 62 and the regeneration passage 64 and a regeneration position that connects the head-side passage 62 and the regeneration passage 64.

[0060] In this embodiment, the boom regeneration valve 6B is driven by pilot pressure. However, the boom regeneration valve 6B can also be driven by an electric actuator.

[0061] More specifically, such as Figure 5 As shown, one end face of the boom regeneration valve core 6B faces the pilot chamber 60 formed by the cover 35, as described above. The boom regeneration valve core 6B moves from the neutral position to the regeneration position when the pilot pressure entering the pilot chamber 60 increases. Furthermore, the opening area between the head-side passage 62 and the regeneration passage 64 increases with the increasing pilot pressure entering the pilot chamber 60. Figure 2 As shown, when the pilot pressure in the pilot chamber 60 exceeds the set value, the head-side passage 62 is also connected to the regeneration / regeneration tank passage 63. Furthermore, the spring 36 disposed inside the cover 35 serves to maintain the boom regeneration valve core 6B in a neutral position.

[0062] As mentioned above, the boom drive valve core 5 closes the boom tank passage 52 when the boom is in the lower position. Therefore, when using the boom regeneration valve core 6B, the boom regeneration valve core 6B moves in the same way as the boom drive valve core 5 when the boom is in the lower position.

[0063] Other, Figure 5 In order to use the lifting valve 91 of the check valve 9 to constantly close the rod side passage 61, a pressing member 94 and a fixing member 95 can be used instead of the spring 92 and the cover 93.

[0064] In the multi-control valve 1 described above, boom regeneration is achieved when the boom regeneration valve core 6A is inserted into the third sliding hole 23, and boom retraction is achieved when the boom retraction valve core 6B is inserted into the third sliding hole 23. That is, using the boom regeneration valve core 6A as the boom auxiliary valve core 6 enables a hydraulic circuit capable of boom regeneration, and using the boom retraction valve core 6B as the boom auxiliary valve core 6 enables a hydraulic circuit capable of boom retraction. Therefore, even without replacing the multi-control valve 1 itself, and without replacing the housing 2, only the boom auxiliary valve core 6 needs to be replaced to achieve both the boom regeneration and boom retraction hydraulic circuits.

[0065] (Modified Example)

[0066] This invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of this invention.

[0067] For example, the boom regeneration valve core 6A and the boom recovery valve core 6B do not necessarily need to be inserted into the sliding hole of the insertion unloading valve core 7; they can be inserted into a different sliding hole than the sliding hole of the insertion unloading valve core 7. However, with this structure, compared to the case where the sliding hole of the insertion unloading valve core 7 is provided on the housing 2 independently of the sliding hole of the insertion boom regeneration valve core 6A or the boom recovery valve core 6B, the housing 2 can be miniaturized. Thus, a multi-control valve 1 that reduces costs can be provided.

[0068] Furthermore, the multiple control valve 1 may also exclude the unloading valve core 7.

[0069] (Summarize)

[0070] The multi-control valve of the present invention is a multi-control valve for hydraulic excavators, characterized in that it comprises: a stick drive valve core, a boom drive valve core, a boom auxiliary valve core, and a housing that slidably holds the stick drive valve core, the boom drive valve core, and the boom auxiliary valve core; the housing is provided with: a stick parallel passage, a stick retraction supply passage, and a stick extension supply passage opened and closed by the stick drive valve core; a boom parallel passage, a boom lifting supply passage, and a boom lowering supply passage opened and closed by the boom drive valve core; a sliding hole into which the boom auxiliary valve core is inserted; and a supply passage from the boom lifting supply passage. The forked passage abuts the head side passage of the sliding hole; the forked supply passage of the boom descending passage abuts the rod side passage of the sliding hole; and the regeneration passage abuts the parallel passage of the boom from the sliding hole; the boom auxiliary valve core is either a boom regeneration valve core or a boom regeneration valve core, the boom regeneration valve core moves between a neutral position that blocks the head side passage and the rod side passage and a regeneration position that connects the head side passage and the rod side passage, and the boom regeneration valve core moves between a neutral position that blocks the head side passage and the regeneration passage and a regeneration position that connects the head side passage and the regeneration passage.

[0071] Based on the above structure, boom regeneration can be achieved by inserting a boom regeneration valve core into the sliding hole, and boom retraction can be achieved by inserting a boom retraction valve core into the sliding hole. Therefore, even without replacing the multi-control valve itself, and without replacing the housing, only the boom auxiliary valve core needs to be replaced to achieve both the hydraulic circuit for boom regeneration and the hydraulic circuit for boom retraction.

[0072] Alternatively, the housing may have a pump port and a tank port, with a pump passage from the pump port to the sliding hole and a tank passage from the tank port to the sliding hole. The stick and boom have parallel passages branching from the pump passage. An unloading valve core for adjusting the opening area between the pump passage and the tank passage is inserted into the sliding hole. This structure allows for a smaller housing compared to a case where the sliding hole for inserting the unloading valve core is provided independently of the sliding hole for inserting the boom regeneration valve core or the boom recovery valve core. This enables the provision of multiple control valves that reduce costs.

[0073] For example, the housing may be provided with a boom canister passage and a stick canister passage, and the boom drive valve core may move between a neutral position, a boom raising position, and a boom lowering position. In the boom raising position, the boom parallel passage is connected to the boom raising supply passage, and the boom lowering supply passage is connected to the boom canister passage. In the boom lowering position, the boom parallel passage is connected to the boom lowering supply passage, and the boom raising supply passage is closed.

Claims

1. A multi-control valve, It is a multi-control valve used in hydraulic excavators, and features: Valve core for boom drive boom drive valve core, boom auxiliary valve core, and The housing of the boom drive valve core, the boom drive valve core, and the boom auxiliary valve core is slidably retained; The housing is provided with: a parallel passage for the stick, a stick retraction supply passage, and a stick extension supply passage, which are opened and closed by the valve core driven by the stick; a parallel passage for the boom, a boom lifting supply passage, and a boom lowering supply passage, which are opened and closed by the valve core driven by the boom; a sliding hole into which the boom auxiliary valve core is inserted; a head-side passage that branches off from the boom lifting supply passage and abuts the sliding hole; a rod-side passage that branches off from the boom lowering supply passage and abuts the sliding hole; and a regeneration passage that abuts the parallel passage for the stick from the sliding hole. The boom auxiliary valve core is either a boom regeneration valve core or a boom recovery valve core. The boom regeneration valve core moves between a neutral position that blocks the head-side passage and the rod-side passage, and a regeneration position that connects the head-side passage and the rod-side passage. The boom regeneration valve core moves between a neutral position that blocks the head-side passage and the regeneration passage and a regeneration position that connects the head-side passage and the regeneration passage.

2. The multi-control valve according to claim 1, characterized in that, The housing has a pump port and a tank port. The housing is provided with a pump passage from the pump port to the sliding hole and a tank passage from the tank port to the sliding hole; The parallel passage for the stick and the parallel passage for the boom branch off from the pump passage; An unloading valve core for adjusting the opening area between the pump passage and the tank passage is inserted into the sliding hole.

3. The multi-control valve according to claim 1 or 2, characterized in that, The housing is provided with a canister passage for the boom and a canister passage for the stick. The boom drive valve core moves between a neutral position, a boom raising position, and a boom lowering position. In the boom raising position, it connects the boom parallel passage with the boom raising supply passage and connects the boom lowering supply passage with the boom tank passage. In the boom lowering position, it connects the boom parallel passage with the boom lowering supply passage and closes the boom raising supply passage.

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