Pump device

Abstract

To suppress temperature rise of a lubrication oil in a gear chamber to extend a replacement cycle of the lubrication oil, thereby improving maintainability and reduce a damage risk of a seal member etc. caused by temperature rise of the lubrication oil.SOLUTION: In a gear chamber 23 of a gear casing 22, an oil pipeline 57 is provided in a state that at least a part of an internal passage 58 is immersed in a lubrication oil 32. A hydraulic oil (a pressure oil) discharged from a fan pump 52 is guided to the oil pipeline 57. Accordingly, the hydraulic oil cooled by an oil cooler 13 is utilized to suppress temperature rise of the lubrication oil 32 in the gear chamber 23 without depending on cooling air generated by a cooling fan 14.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a pump device that is mounted on a construction machine such as a hydraulic excavator or a hydraulic crane, and is driven by a prime mover to discharge hydraulic oil for operation. [Background technology]

[0002] Generally, construction machinery such as hydraulic excavators and hydraulic cranes includes a vehicle body capable of self-propelling and a working device attached to the vehicle body. The vehicle body of the construction machinery is equipped with a prime mover such as an engine or an electric motor, a pump device, etc. The pump device is driven by the prime mover to supply hydraulic oil (pressurized oil for operation) to various hydraulic actuators attached to the vehicle body and the working device.

[0003] The pump device includes a gear casing with a gear chamber inside, a plurality of gears rotatably mounted in the gear chamber and meshing with adjacent gears, lubricating oil stored in the gear chamber to lubricate the meshing portions between the plurality of gears, and a plurality of hydraulic pumps mounted in the gear casing and rotating together with the gears to supply hydraulic oil to the hydraulic actuator.

[0004] Furthermore, in the gear chamber of the gear casing, the lubricating oil is stirred by the multiple gears, and the stirring resistance at this time causes the temperature of the lubricating oil (oil temperature) to rise. To address this, some pump devices are configured so that a cooling cylinder that protrudes into the gear chamber is installed in the gear casing, and the lubricating oil is air-cooled by circulating outside air inside the cooling cylinder (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-103317 Summary of the Invention [Problem to be solved by the invention]

[0006] The invention of Patent Document 1 cools the lubricating oil by circulating air through a cooling tube protruding into the gear chamber, transferring heat to the air. However, the pump chamber, where the pump device is located, is separated by a partition from the engine chamber, where the cooling device (cooling fan) is located. Therefore, the cooling air generated by the cooling fan has difficulty circulating into the pump chamber, and the lubricating oil cannot be efficiently cooled using the cooling air, resulting in an increase in temperature. This results in accelerated deterioration of the lubricating oil, shortening the lubricating oil replacement cycle and reducing maintainability. Furthermore, if the lubricating oil temperature rises excessively and reaches the guaranteed limit temperature of sealing components, etc., there is an increased risk of damage to those sealing components.

[0007] An object of one embodiment of the present invention is to provide a pump device that suppresses the temperature rise of the lubricating oil in the gear chamber, thereby extending the lubricating oil replacement cycle and improving maintainability, and reducing the risk of damage to sealing members and other components due to the temperature rise of the lubricating oil. [Means for solving the problem]

[0008] One embodiment of the present invention is a pump device comprising a gear casing with a gear chamber inside, a plurality of gears rotatably arranged in the gear chamber, lubricating oil stored in the gear chamber to lubricate the meshing portions between the plurality of gears, and a plurality of hydraulic pumps arranged in the gear casing and rotating together with the gears to supply hydraulic oil to a hydraulic actuator, wherein an oil pipeline is arranged in the gear chamber with at least a portion immersed in the lubricating oil, and the oil pipeline is configured to guide hydraulic oil discharged from any of the plurality of hydraulic pumps. [Effects of the Invention]

[0009] According to one embodiment of the present invention, the temperature rise of the lubricating oil in the gear chamber can be suppressed, the lubricating oil replacement cycle can be extended, improving maintainability, and the risk of damage to sealing members and other components due to a rise in the temperature of the lubricating oil can be reduced. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a left side view of a hydraulic excavator equipped with a pump device according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the rear part of the hydraulic excavator as viewed from the direction of arrows II-II in FIG. 1. [Figure 3] 3 is a cross-sectional view of the pump device according to the first embodiment as seen from the direction of arrows III-III in FIG. 5. [Figure 4] 6 is a cross-sectional view of the pump device as seen from the direction of arrows IV-IV in FIG. 5. [Figure 5] 1 is a partially cutaway plan view showing a pump device according to a first embodiment. [Figure 6] 6 is a cross-sectional view of the pump device as seen from the direction of arrows VI-VI in FIG. 3. [Figure 7] 1 is a hydraulic circuit diagram including a pump device according to a first embodiment. [Figure 8] FIG. 4 is a characteristic diagram showing temperature changes of hydraulic oil and lubricating oil. [Figure 9] 11 is a cross-sectional view of a pump device according to a second embodiment of the present invention, as viewed from the direction of arrows IX-IX in FIG. [Figure 10] 10 is a cross-sectional view of the pump device of FIG. 9 taken at the position of the rotation center of the main pump. [Figure 11] 10 is a cross-sectional view of the pump device as seen from the direction of arrows XI-XI in FIG. 9. [Figure 12] FIG. 4 is a hydraulic circuit diagram including a pump device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pump device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking as an example a case where the pump device is applied to a crawler hydraulic excavator as a construction machine.

[0012] Figures 1 to 8 show a first embodiment of the present invention. In Figure 1, a hydraulic excavator 1 as a construction machine includes a self-propelled crawler-type lower traveling body 2, an upper rotating body 3 that is mounted on the lower traveling body 2 so as to be able to rotate and that forms a vehicle body together with the lower traveling body 2, and a working device 4 that is rotatably provided on the front side of the upper rotating body 3. The working device 4 is used for performing work such as excavating earth and sand.

[0013] The upper rotating body 3 has a rotating frame 5 formed as a support structure. A counterweight 6 is provided at the rear of the rotating frame 5 to balance the weight of the working device 4. The upper rotating body 3 is covered with an exterior cover 7 from the counterweight 6 forward.

[0014] 2, a partition wall 8 extending in the up-down and front-rear directions is provided at the rear of the upper rotating body 3 in a position slightly to the left of the center in the left-right direction. At the rear of the upper rotating body 3, the interior of the exterior cover 7 is divided by the partition wall 8 to form an engine room 9 and a pump room 10. An engine 11 and a heat exchanger 12 (described later) are disposed in the engine room 9, and a pump unit 21 is disposed in the pump room 10.

[0015] The engine 11 serving as a prime mover is configured as an internal combustion engine such as a diesel engine, and is provided in the engine compartment 9. The engine 11 is installed horizontally on the revolving frame 5, extending in the left-right direction. An output shaft 11A (see FIG. 7) of the engine 11 is connected to a fan pump 52 (described later) and the like. A typical output shaft 11A outputs rotation that has been reduced via a reduction gear (not shown). Note that, in addition to the engine 11, the prime mover may be a hybrid prime mover that combines an internal combustion engine and an electric motor, or an electric motor alone.

[0016] The heat exchanger 12 is located on the right side of the engine 11 and is provided in the engine compartment 9. The heat exchanger 12 includes an oil cooler 13 that cools the hydraulic oil, a radiator (not shown) that cools the engine coolant, and a cooling fan 14 that supplies cooling air to the oil cooler 13 and the radiator.

[0017] The cooling fan 14 is composed of an oil cooler 13, a fan body 14A consisting of a propeller fan facing the radiator, and a fan motor 14B that rotates the fan body 14A. The fan motor 14B is configured as a hydraulic motor powered by hydraulic oil (pressurized oil). The fan motor 14B is connected to a fan pump 52 and a hydraulic oil tank 15, which will be described later.

[0018] The hydraulic oil tank 15 is provided on the upper rotating body 3. The hydraulic oil tank 15 stores hydraulic oil to be supplied to the hydraulic actuators. Here, the hydraulic oil is cooled by the oil cooler 13 and is therefore maintained at a lower temperature than the lubricating oil 32 described below.

[0019] 7, the upper rotating body 3 is further provided with a control valve 16 that supplies and discharges hydraulic oil to and from the hydraulic actuator, and a controller 17 that controls the control valve 16, the first main pump 33, the second main pump 49, the fan pump 52, etc. The hydraulic oil tank 15 is further provided with an oil thermometer 18 that measures the temperature of the hydraulic oil and outputs the value to the controller 17. The controller 17 reads the temperature of the hydraulic oil output from the oil thermometer 18, and outputs a command value to a fan regulator 55 (described later) to control the cooling fan 14.

[0020] Next, a description will be given of the configuration of the pump device 21, which is a characteristic part of this embodiment. As shown in Fig. 2, the pump device 21 is attached to the left side (output side) of the engine 11. The pump device 21 is driven by the engine 11 to discharge hydraulic oil toward the hydraulic actuator.

[0021] The pump device 21 is configured to include a gear casing 22, a gear chamber 23, a drive gear 24, a first driven gear 27, a second driven gear 28, and lubricating oil 32, which will be described later. In describing the configuration of the pump device 21, the engine 11 side will be referred to as the right side, the side opposite the engine 11 as the left side, the working device 4 side as the front side, and the counterweight 6 side as the rear side.

[0022] The gear casing 22 is attached to the left side of the engine 11. As shown in Figures 3 to 6, the gear casing 22 is formed as a horizontally long box-like case extending in the front-to-rear direction as a whole. The interior of the gear casing 22 forms a gear chamber 23, and this gear chamber 23 contains a drive gear 24, a first driven gear 27, and a second driven gear 28, which will be described later.

[0023] A right wall portion 22A of the gear casing 22, which faces the engine 11, is attached to the engine 11 with bolts. Meanwhile, a first main pump 33, a second main pump 49, and a fan pump 52, which will be described later, are attached with bolts to a left wall portion 22B on the opposite side of the right wall portion 22A. The gear casing 22 includes a right wall portion 22A and a left wall portion 22B that face each other with a gap between them in the left-right direction, and a peripheral wall portion 22C between the right wall portion 22A and the left wall portion 22B.

[0024] 3 and 4, the right wall portion 22A is provided with a first recess 22D in the middle in the front-rear direction for attaching a bearing 25, and two second recesses 22E (only one shown) for attaching a bearing 26 at positions sandwiching the first recess 22D in the front-rear direction. Furthermore, the left wall portion 22B is provided with a third recess 22F coaxial with the first recess 22D and two fourth recesses 22G (only one shown) coaxial with the two second recesses 22E, corresponding to the first recess 22D and the two second recesses 22E. The six recesses 22D, 22E, 22F, and 22G are arranged so that their axial centers are at the same height.

[0025] 3, the drive gear 24 serving as a gear is rotatably provided in a gear chamber 23 inside the gear casing 22. The drive gear 24 includes a cylindrical hollow shaft 24A extending in the left-right direction, and a gear body 24B provided in the middle of the hollow shaft 24A in the longitudinal direction.

[0026] The drive gear 24 has a hollow shaft 24A whose first end is rotatably supported in the first recess 22D of the right wall portion 22A via a bearing 25, and whose second end is rotatably supported in the third recess 22F of the left wall portion 22B via a bearing 26. The first end of the hollow shaft 24A is spline-coupled to an output shaft 11A of the engine 11 so as to rotate integrally therewith, and the second end is spline-coupled to a rotating shaft 54 ​​of a fan pump 52 (described later) so as to rotate integrally therewith. As a result, the rotation of the output shaft 11A of the engine 11 is transmitted to the rotating shaft 54 ​​of the fan pump 52 via the drive gear 24.

[0027] Furthermore, the gear body 24B is aligned in the front-rear direction and meshes with a gear body 27B of a first driven gear 27 and a gear body 28B of a second driven gear 28, which will be described later. As a result, the drive gear 24 meshes with the first driven gear 27 and the second driven gear 28 in the gear chamber 23 of the gear casing 22 and rotates together with them, thereby transmitting the rotation of the engine 11 to the first driven gear 27 and the second driven gear 28.

[0028] 4, the first driven gear 27 serving as a gear is rotatably provided in the gear chamber 23 inside the gear casing 22, adjacent to the rear side of the drive gear 24. The first driven gear 27 includes a cylindrical hollow shaft 27A extending in the left-right direction, and a gear body 27B provided in the middle of the hollow shaft 27A in the longitudinal direction.

[0029] The first driven gear 27 has a hollow shaft 27A whose first end is rotatably supported via a bearing 26 in a second recess 22E located behind the right wall 22A, and whose second end is rotatably supported via a bearing 25 in a fourth recess 22G located behind the left wall 22B. A rotating shaft 36 of a first main pump 33 (described later) is spline-coupled to the hollow shaft 27A so as to rotate integrally with the first driven gear 27. This allows the first driven gear 27 to rotate integrally with the rotating shaft 36 of the first main pump 33.

[0030] Furthermore, the gear body 27B is arranged next to the rear side of the drive gear 24 and meshes with the drive gear 24. As a result, the first driven gear 27 meshes with the drive gear 24 in the gear chamber 23 of the gear casing 22 and rotates together, thereby transmitting the rotation of the engine 11 to the first main pump 33 via the drive gear 24.

[0031] The second driven gear 28, which serves as a gear, is rotatably provided in the gear chamber 23 inside the gear casing 22, adjacent to the front side of the drive gear 24. Similar to the first driven gear 27, the second driven gear 28 includes a cylindrical hollow shaft 28A extending in the left-right direction, and a gear body 28B provided in the middle of the hollow shaft 28A in the longitudinal direction.

[0032] The second driven gear 28 has a hollow shaft 28A whose first end is rotatably supported via a bearing 26 in a second recess located in front of the right wall portion 22A, and whose second end is rotatably supported via a bearing 25 in a fourth recess located in front of the left wall portion 22B. A rotating shaft 36 of a second main pump 49 (described later) is spline-coupled to the hollow shaft 28A so as to rotate integrally therewith. This allows the second driven gear 28 to rotate integrally with the rotating shaft 36 of the second main pump 49.

[0033] Furthermore, the gear body 28B is arranged next to the front side of the drive gear 24 and meshes with the drive gear 24. As a result, the second driven gear 28 meshes with the drive gear 24 in the gear chamber 23 of the gear casing 22 and rotates together, thereby transmitting the rotation of the engine 11 to the second main pump 49 via the drive gear 24.

[0034] Therefore, the drive gear 24, the first driven gear 27, and the second driven gear 28 are arranged in the gear chamber 23 of the gear casing 22 with adjacent gears meshing with each other. Also, as shown in Fig. 6, an inlet passage 58C (first passage forming portion 58A) of an internal passage 58 (described later) is arranged below an engagement portion 29 between the gear body 24B of the drive gear 24 and the gear body 27B of the first driven gear 27. Also, an outlet passage 58E (second passage forming portion 58B) of the internal passage 58 (described later) is arranged below an engagement portion 30 between the gear body 24B of the drive gear 24 and the gear body 28B of the second driven gear 28.

[0035] 7, a plurality of seal members 31 are provided in the gear casing 22. The seal members 31 provide a liquid-tight seal between the gear casing 22 and the output shaft 11A of the engine 11, between the gear casing 22 and the rotating shaft 54 ​​of the fan pump 52, between the gear casing 22 and the rotating shaft 36 of the first main pump 33, and between the gear casing 22 and the rotating shaft 36 of the second main pump 49. The plurality of seal members 31 are formed, for example, from an elastic resin material.

[0036] Lubricating oil 32 is stored in gear chamber 23 of gear casing 22. Lubricating oil 32 lubricates meshing portion 29 between drive gear 24 and first driven gear 27, meshing portion 30 between drive gear 24 and second driven gear 28, bearings 25, 26, etc. As shown in FIG. 6 , when gear casing 22 is arranged horizontally, the height of the liquid surface of lubricating oil 32 is set so that the lower parts of gear body 24B of drive gear 24, gear body 27B of first driven gear 27, and gear body 28B of second driven gear 28 are always immersed in lubricating oil (set at a position higher than the lower parts of gear body 24B of drive gear 24, gear body 27B of first driven gear 27, and gear body 28B of second driven gear 28).

[0037] As shown in Figures 4 and 5, the first main pump 33, which serves as a hydraulic pump, is provided on the left wall portion 22B of the gear casing 22. The first main pump 33 is rotated together with the first driven gear 27 to supply hydraulic oil to hydraulic actuators such as the travel motor of the lower traveling body 2, the swing motor of the swing device, and the hydraulic cylinder of the working device 4. The first main pump 33 is configured, for example, as a swash plate-type variable displacement axial piston pump. The first main pump 33 includes a pump casing 34, a rotating shaft 36, a cylinder block 37, pistons 39, a cradle 41, a swash plate 42, a tilt actuator 45, and a main regulator 46, which will be described later.

[0038] The pump casing 34 forms the outer shell of the first main pump 33. The pump casing 34 is attached to the rear side of the left wall 22B of the gear casing 22. The pump casing 34 includes a bottom 34A on the right side facing the left wall 22B, a tubular portion 34B that extends from the periphery of the bottom 34A toward the opposite side (left side) of the gear casing 22 and opens to the left, a rear casing 34C attached to the tubular portion 34B so as to close the opening of the tubular portion 34B, and an actuator attachment portion 34D provided on the lower left of the tubular portion 34B. The bottom 34A and the tubular portion 34B form a front casing.

[0039] The rear casing 34C is formed with a suction pipe 34E and a discharge pipe 34F. The actuator mounting portion 34D is formed, for example, in a box shape, and a part of the inside forms a part of a tilt control cylinder 45A of the tilt actuator 45, which will be described later.

[0040] The drain chamber 35 is provided inside the pump casing 34. The drain chamber 35 stores hydraulic oil leaking from sliding parts such as between the cylinder 38 and the piston 39, and between the cradle 41 and the swash plate 42, and discharges excess hydraulic oil (drain oil) to the outside.

[0041] The rotary shaft 36 extends in the axial direction (left-right direction) of the cylindrical portion 34B of the pump casing 34. The rotary shaft 36 is rotatably supported by the bottom portion 34A and the rear casing 34C. A first end of the rotary shaft 36 is splined into the hollow shaft 27A so as to rotate integrally with the first driven gear 27.

[0042] The cylinder block 37 is provided in a drain chamber 35 inside the pump casing 34. The cylinder block 37 has a plurality of cylinders 38 (only one shown) arranged circumferentially, with a rotary shaft 36 splined to its center. Pistons 39 are slidably inserted into the plurality of cylinders 38 of the cylinder block 37. A valve plate 40 that slides against the cylinder block 37 is disposed between the cylinder block 37 and the rear casing 34C. The valve plate 40 has suction ports 40A and discharge ports 40B formed in it to connect the cylinders 38 to the suction pipe 34E and discharge pipe 34F formed in the rear casing 34C.

[0043] A cradle 41 is fixed to the left surface of the bottom 34A of the pump casing 34. The cradle 41 slidably supports a swash plate 42, which serves as a displacement variable mechanism, within the pump casing 34 and guides the tilt of the swash plate 42. A cam plate 43 and shoes 44 are disposed between the swash plate 42 and the pistons 39. The tilt of the swash plate 42 is transmitted to the pistons 39 via the cam plate 43 and shoes 44, determining the reciprocating stroke of the pistons 39 within the cylinders 38, i.e., the displacement volume. A portion of the hydraulic oil is supplied to the sliding surfaces between the cradle 41 and the swash plate 42 for lubrication, and the lubricating hydraulic oil flows into the drain chamber 35 and is stored there.

[0044] The tilt actuator 45 is provided in the actuator mounting portion 34D of the pump casing 34. The tilt actuator 45 tilts the swash plate 42 in response to a tilt control pressure supplied or discharged from the outside. The tilt actuator 45 includes a tilt control cylinder 45A formed in the actuator mounting portion 34D and a servo piston 45B provided in the tilt control cylinder 45A.

[0045] The tilt control cylinder 45A is formed as a circular hole extending in the front-rear direction, perpendicular to the axial direction (left-right direction) of the cylindrical portion 34B of the pump casing 34. The servo piston 45B is slidably inserted into the tilt control cylinder 45A. The tip of the arm 42A of the swash plate 42 engages with the middle portion of the servo piston 45B in the longitudinal direction.

[0046] The tilt actuator 45 supplies and discharges tilt control pressure based on a command value from the controller 17 to the main regulator 46, thereby slidingly displacing the servo piston 45B within the tilt control cylinder 45A. The displacement of the servo piston 45B is transmitted to the swash plate 42 via the arm 42A, allowing the tilt actuator 45 to adjust the tilt angle of the swash plate 42.

[0047] 4 and 7, the main regulator 46 is attached to the actuator attachment portion 34D of the pump casing 34. The main regulator 46 displaces a spool valve in response to the tilting operation of the swash plate 42, thereby feedback-controlling the tilting actuator 45 via a feedback link (neither of which is shown).

[0048] In the first main pump 33 configured as described above, when the rotation of the engine 11 is transmitted to the rotary shaft 36 via the drive gear 24 and the first driven gear 27, the cylinder block 37 rotates together with the rotary shaft 36. As the cylinder block 37 rotates, each shoe 44 slides on the inclined swash plate 42, causing the piston 39 in each cylinder 38 of the cylinder block 37 to slide between the top dead center and the bottom dead center. As the piston 39 reciprocates, the first main pump 33 repeatedly performs a suction stroke in which hydraulic oil is drawn into the cylinder 38 and a discharge stroke in which the hydraulic oil in the cylinder 38 is discharged as pressurized oil.

[0049] As a result, as shown in FIG. 7, the first main pump 33 discharges hydraulic oil that has flowed in from the hydraulic oil tank 15 through the first inlet pipeline 47 as pressurized oil to the first outlet pipeline 48, and this pressurized oil can be supplied to various hydraulic actuators via the first outlet pipeline 48 and the control valve 16.

[0050] On the other hand, when adjusting the pump capacity (discharge amount of pressure oil) of the first main pump 33, the tilt actuator 45 is operated by the main regulator 46 to change the tilt angle of the swash plate 42. This increases or decreases the stroke amount of each piston 39, making it possible to variably control the pump capacity of the first main pump 33.

[0051] 5, the second main pump 49 as a hydraulic pump is configured in the same manner as the first main pump 33. Therefore, the second main pump 49 is given the same reference numerals as the first main pump 33, and a description of the configuration will be omitted.

[0052] The second main pump 49 repeats a suction stroke in which it sucks in hydraulic oil and a discharge stroke in which it discharges the hydraulic oil as pressurized oil as the rotation of the engine 11 is transmitted to the rotary shaft 36 via the drive gear 24 and the second driven gear 28. As a result, as shown in Fig. 7, the second main pump 49 discharges the hydraulic oil that has flowed in from the hydraulic oil tank 15 through the second inlet pipe 50 to the second outlet pipe 51 as pressurized oil, and can supply this pressurized oil to various hydraulic actuators via the second outlet pipe 51 and the control valve 16.

[0053] 3 and 5, the fan pump 52 as a hydraulic pump is smaller than the first main pump 33, but has the same basic configuration as the first main pump 33. Therefore, for the fan pump 52, new reference numerals are assigned to the pump casing 53, the rotating shaft 54, and the fan regulator 55 shown in FIGS. 3, 5, and 7, and a description of the other configurations will be omitted.

[0054] When the rotation of the engine 11 is transmitted to the rotary shaft 54 ​​via the drive gear 24, the cylinder block of the fan pump 52 rotates together with the rotary shaft 54. As the cylinder block rotates, each shoe slides on an inclined swash plate, causing the pistons in the cylinders of the cylinder block to slide between top dead center and bottom dead center. Due to the reciprocating motion of the pistons, the fan pump 52 repeatedly performs a suction stroke in which hydraulic oil is sucked into the cylinder, and a discharge stroke in which the hydraulic oil in the cylinder is discharged as pressurized oil.

[0055] As a result, as shown in Figure 7, the fan pump 52 discharges the hydraulic oil that has flowed in from the hydraulic oil tank 15 through the external suction pipe 59 of the oil pipe 57 described later as pressurized oil to the external discharge pipe 60, and can supply this pressurized oil to the fan motor 14B of the cooling fan 14 via the external supply pipe 61.

[0056] On the other hand, when adjusting the pump capacity (discharge amount of pressure oil) of the fan pump 52, the tilt actuator is operated by the fan regulator 55 to change the tilt angle of the swash plate. This increases or decreases the stroke amount of each piston, and the pump capacity of the fan pump 52 can be variably controlled.

[0057] The pilot pump 56 is attached to the left side of the pump casing 53 of the fan pump 52. The pilot pump 56 supplies pilot pressure oil as a power source for operating the control valve 16, the main regulator 46, the fan regulator 55, etc. As shown in Fig. 7, the pilot pump 56 includes a pump section (not shown) that is connected to and driven by the rotary shaft 54.

[0058] Next, the configuration and effects of the cooling oil pipe 57, which is a characteristic feature of this embodiment, will be described.

[0059] Oil pipe 57 is a pipe that supplies hydraulic oil (pressurized oil) discharged from fan pump 52 to fan motor 14B of cooling fan 14 via gear chamber 23 of gear casing 22, and then returns it to hydraulic oil tank 15. A portion of oil pipe 57 is immersed in lubricating oil 32 in gear chamber 23, and hydraulic oil discharged from fan pump 52 flows through the position immersed in lubricating oil 32. Oil pipe 57 is composed of an internal passage 58, a suction external pipe 59, a discharge external pipe 60, a supply external pipe 61, and a return external pipe 62.

[0060] The internal passage 58 is provided as a passage built into the gear casing 22. The internal passage 58 transfers heat from the lubricating oil 32 to the flowing hydraulic oil. The internal passage 58 includes a first passage forming portion 58A, a second passage forming portion 58B, an inlet passage 58C, an intermediate passage 58D, and an outlet passage 58E.

[0061] 5 and 6, the first passage forming portion 58A is located below (directly below) the meshing portion 29 between the gear body 24B of the drive gear 24 and the gear body 27B of the first driven gear 27, and is formed as a cylindrical body extending in the left-right direction across the right wall portion 22A and the left wall portion 22B. At least a portion of the first passage forming portion 58A, specifically, most of it except for the upper portion, is immersed in the lubricating oil 32. The cylindrical first passage forming portion 58A is provided to form part of the inlet passage 58C, and performs heat exchange between the hydraulic oil flowing inside and the external lubricating oil 32.

[0062] The second passage forming portion 58B is located below (directly below) the meshing portion 30 between the gear body 24B of the drive gear 24 and the gear body 28B of the second driven gear 28, and is formed as a cylindrical body extending in the left-right direction across the right wall portion 22A and the left wall portion 22B. Similar to the first passage forming portion 58A, at least a portion of the second passage forming portion 58B, specifically, most of the portion excluding the upper portion, is immersed in the lubricating oil 32. The cylindrical second passage forming portion 58B is provided to form part of the outlet passage 58E, and performs heat exchange between the hydraulic oil flowing inside and the external lubricating oil 32.

[0063] The inlet passage 58C is located rearward of the drive gear 24 and extends in the left-right direction parallel to the axis of the hollow shaft 24A. The left side of the inlet passage 58C opens into the left wall portion 22B, and the right side reaches the right wall portion 22A and is connected to the intermediate passage 58D. Most of the inlet passage 58C is formed by passing through the first passage forming portion 58A.

[0064] The intermediate passage 58D is provided so as to extend laterally from the right end of the inlet passage 58C toward the front side of the right wall portion 22A. The intermediate passage 58D is disposed at a position closer to the gear chamber 23 than the outside. This allows the intermediate passage 58D to efficiently transfer the heat of the lubricating oil 32 to the flowing hydraulic oil. In other words, the intermediate passage 58D can release the heat of the lubricating oil 32 to the hydraulic oil.

[0065] The outlet passage 58E is located in front of the drive gear 24 and extends in the left-right direction parallel to the axis of the hollow shaft 24A. The right side of the outlet passage 58E is connected to the intermediate passage 58D at the right wall portion 22A, and the left side of the outlet passage 58E opens to the left wall portion 22B. Most of the outlet passage 58E is formed by passing through the second passage forming portion 58B.

[0066] The internal passage 58 formed in this manner allows the hydraulic oil to flow sequentially through the inlet passage 58C, the intermediate passage 58D, and the outlet passage 58E, thereby dissipating the heat of the lubricating oil 32 transmitted from the circumferential surface of the first passage forming portion 58A, the circumferential surface of the second passage forming portion 58B, and the inner surface of the right wall portion 22A to the hydraulic oil.

[0067] The suction external conduit 59 consists of piping and hoses that connect the hydraulic oil tank 15 and the suction side of the fan pump 52. The discharge external conduit 60 consists of hoses that connect the discharge side of the fan pump 52 and the inlet passage 58C of the internal passage 58. The supply external conduit 61 consists of piping and hoses that connect the outlet passage 58E of the internal passage 58 and the inlet side of the fan motor 14B of the cooling fan 14. Furthermore, the return external conduit 62 consists of piping and hoses that connect the outlet side of the fan motor 14B and the hydraulic oil tank 15.

[0068] As a result, the oil pipe 57 supplies hydraulic oil in the hydraulic oil tank 15 to the fan pump 52 via the suction external pipe 59, and supplies hydraulic oil discharged from the fan pump 52 to the internal passage 58 via the discharge external pipe 60. In this internal passage 58, heat from the lubricating oil 32 in the gear chamber 23 is transferred (dissipated) to the circulating hydraulic oil, thereby suppressing a rise in the temperature of the lubricating oil 32. The oil pipe 57 also supplies hydraulic oil to the fan motor 14B of the cooling fan 14 via the supply external pipe 61, causing the fan main body 14A to rotate. The hydraulic oil that has driven the cooling fan 14 is then returned to the hydraulic oil tank 15 via the return external pipe 62, thereby circulating the hydraulic oil through the oil pipe 57.

[0069] Next, the temperature changes of the hydraulic oil and the lubricating oil 32 in the first embodiment will be described with reference to FIG.

[0070] When the pump device 21 starts operating at time t0, the hydraulic oil temperature TO rises faster than the lubricating oil temperature TG1. When the hydraulic oil temperature TO reaches the specified value TOD at time t1, the controller 17 sends a command to the fan regulator 55 to increase the hydraulic oil discharge flow rate of the fan pump 52. The increase in the discharge flow rate of the fan pump 52 increases the rotation speed of the fan motor 14B of the cooling fan 14 and the fan main body 14A. This increases the hydraulic oil cooling effect of the oil cooler 13, so the hydraulic oil temperature TO is maintained near the specified value TOD.

[0071] In the conventional pump device structure, the lubricating oil temperature TG2 continues to rise due to stirring by the multiple gears, and at time t2, it becomes higher than the hydraulic oil temperature TO. The lubricating oil temperature TG2 continues to rise, and at time t3, it exceeds the guaranteed value TGT, which is the limit temperature at which the quality of the lubricating oil 32, sealing members, etc. is guaranteed.

[0072] In contrast, in the structure of the pump device 21 according to this embodiment, when the pump device 21 starts operating, the hydraulic oil discharged from the fan pump 52 flows through the internal passage 58 of the oil pipe 57, and the lubricating oil temperature TG1 receives heat from the hydraulic oil circulating through the internal passage 58, causing the temperature to rise faster than the lubricating oil temperature TG2 in the prior art. Meanwhile, when the hydraulic oil temperature TO reaches the specified value TOD at time t1, the controller 17 commands the fan pump 52 to increase the discharge flow rate. This increases the hydraulic oil cooling effect of the oil cooler 13, allowing the hydraulic oil temperature TO to be maintained near the specified value TOD.

[0073] Furthermore, the lubricating oil temperature TG1 also begins to drop because the heat of the lubricating oil 32 in the gear chamber 23 escapes to the hydraulic oil flowing through the internal passage 58. Therefore, even at time t3 when the lubricating oil temperature TG2 exceeds the guaranteed value TGT in the conventional structure, in this embodiment, the hydraulic oil temperature TO remains constant near the specified value TOD, and because heat escapes to the hydraulic oil in the internal passage 58, the lubricating oil temperature TG1 is also maintained constant and does not exceed the guaranteed value TGT.

[0074] Furthermore, when the discharge flow rate of the hydraulic oil from the fan pump 52 increases in response to a command from the controller 17, the flow rate of the hydraulic oil flowing through the internal passage 58 increases, and the amount of heat escaping into the hydraulic oil increases, making it possible to further suppress the rise in the lubricating oil temperature TG1. Furthermore, because the internal passage 58 guides the high-pressure hydraulic oil discharged from the fan pump 52, it is possible to ensure a stable flow of hydraulic oil and maintain the cooling effect without requiring an external hydraulic source (such as a pump).

[0075] Next, the operation of the pump device 21 according to this embodiment will be described. In the pump device 21, the drive gear 24 is rotated by the output shaft 11A of the engine 11, which causes the first driven gear 27 and the second driven gear 28 meshed with the drive gear 24 to rotate.

[0076] The first main pump 33, with its rotary shaft 36 rotating together with the first driven gear 27, discharges the hydraulic oil drawn in from a first inlet pipe 47 as pressurized oil to a first outlet pipe 48. The second main pump 49, with its rotary shaft 36 rotating together with the second driven gear 28, discharges the hydraulic oil drawn in from a second inlet pipe 50 as pressurized oil to a second outlet pipe 51.

[0077] The pressure oil discharged from the first main pump 33 and the second main pump 49 is supplied to various hydraulic actuators through the control valve 16. The hydraulic oil supplied to the hydraulic actuators is cooled in the oil cooler 13 and then returned to the hydraulic oil tank 15.

[0078] Meanwhile, the fan pump 52, as its rotary shaft 54 ​​rotates together with the output shaft 11A of the engine 11 and the drive gear 24, discharges the hydraulic oil drawn in from an external suction line 59 of the oil line 57 as pressurized oil to an external discharge line 60. The pressurized oil discharged to the external discharge line 60 is supplied to the fan motor 14B of the cooling fan 14 via the internal passage 58 and an external supply line 61, and then returned to the hydraulic oil tank 15 via an external return line 62.

[0079] As described above with reference to FIG. 8 , in the gear chamber 23 of the gear casing 22, the lubricating oil 32 is stirred by the drive gear 24, the first driven gear 27, and the second driven gear 28. This stirring resistance causes the temperature of the lubricating oil 32 to rise. In contrast, the prior art (Patent Document 1) uses a cooling cylinder that protrudes into the gear chamber and is installed in the gear casing. The cooling air generated by the cooling fan cannot reach the pump chamber, which is separated from the engine chamber by a partition wall. This causes the lubricating oil to heat up. This shortens the lubricating oil replacement cycle, reduces maintainability, and increases the risk of damage to sealing components and other components due to the increased temperature of the lubricating oil.

[0080] According to this embodiment, an oil pipe 57 is provided in the gear chamber 23 of the gear casing 22, with at least a portion of the internal passage 58 immersed in the lubricating oil 32. This oil pipe 57 is configured to guide the hydraulic oil (pressurized oil) discharged from the fan pump 52.

[0081] Therefore, by using hydraulic oil cooled by the oil cooler 13, it is possible to suppress a rise in temperature of the lubricating oil 32 in the gear chamber 23 without relying on cooling air from the cooling fan 14. As a result, the temperature TG1 of the lubricating oil 32 can be kept below the guaranteed value TGT. This allows for a longer replacement cycle for the lubricating oil 32, the seal member 31, etc., improving maintainability. In addition, since an oil cooler for the lubricating oil 32 is no longer necessary, the number of parts can be reduced and costs can be kept down. Meanwhile, because the hydraulic oil is pumped by the fan pump 52, a sufficient flow can be ensured, and no pumps are required as additional hydraulic sources, which also helps to keep costs down.

[0082] Furthermore, an inlet passage 58C (first passage forming portion 58A) of the internal passage 58 constituting the oil pipe line 57 is disposed below (directly below) the meshing portion 29 between the adjacent drive gear 24 and first driven gear 27. Also, an outlet passage 58E (second passage forming portion 58B) of the internal passage 58 constituting the oil pipe line 57 is disposed below (directly below) the meshing portion 30 between the adjacent drive gear 24 and second driven gear 28.

[0083] A large amount of lubricating oil 32 is agitated at these meshing portions 29, 30, and the agitation resistance at this time increases the temperature of lubricating oil 32. Therefore, by locating inlet passage 58C and outlet passage 58E directly below meshing portions 29, 30, the temperature increase of lubricating oil 32 can be effectively suppressed by the hydraulic oil flowing through inlet passage 58C and outlet passage 58E.

[0084] Next, Figures 9 to 12 show a second embodiment of the present invention. A feature of this embodiment is that the oil pipe has an arcuate portion that follows the tip circle of the gear. In the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and their description will be omitted. In addition, in the second embodiment, the oil pipe 57 in the first embodiment is eliminated.

[0085] 9 and 10, a first oil line 71 as an oil line according to the second embodiment supplies hydraulic oil (pressurized oil) discharged to a discharge line 34F provided in a rear casing 34C constituting the pump casing 34 of the first main pump 33 as lubricating oil to the sliding portion between the cradle 41 and the swash plate 42 via the gear chamber 23 of the gear casing 22. The hydraulic oil supplied to this sliding portion is returned to the hydraulic oil tank 15 together with excess hydraulic oil (drain oil) in the drain chamber 35.

[0086] The first oil pipe 71 is made up of passages built into the gear casing 22 and the pump casing 34, and a portion of it is immersed in the lubricating oil 32 in the gear chamber 23. The first oil pipe 71 transfers heat from the lubricating oil 32 to the circulating hydraulic oil. The first oil pipe 71 is configured to include a passage forming portion 72, an upstream passage 73, an intermediate passage 74, a downstream passage 75, and a return external pipe 76.

[0087] 11, the passage forming portion 72 is located below (directly below) the meshing portion 29 between the gear body 24B of the adjacent drive gear 24 and the gear body 27B of the first driven gear 27, and is formed to extend in the left-right direction across the right wall portion 22A and the left wall portion 22B. At least a portion of the passage forming portion 72, specifically, more than half of it, is immersed in the lubricating oil 32.

[0088] The passage forming portion 72 is formed as a triangular columnar body with an apex near the meshing portion 29. The passage forming portion 72 includes an inner arc portion 72A that follows the tip circle of the gear body 24B of the drive gear 24, and an outer arc portion 72B that follows the tip circle of the gear body 27B of the first driven gear 27. The inner arc portion 72A is formed in a concave arc shape so as to follow the tip circle with a small gap from the gear body 24B. The outer arc portion 72B is formed in a concave arc shape so as to follow the tip circle with a small gap from the gear body 27B.

[0089] Therefore, the inner arcuate portion 72A can use a gap to restrict the amount of hydraulic oil that is scooped up by the gear body 24B and supplied to the meshing portion 29. Furthermore, the outer arcuate portion 72B can use a gap to restrict the amount of hydraulic oil that is scooped up by the gear body 27B and supplied to the meshing portion 29. As a result, the inner arcuate portion 72A and the outer arcuate portion 72B can reduce stirring resistance and further restrict the temperature rise of the lubricating oil 32.

[0090] The upstream passage 73 is disposed behind the gear casing 22 and the pump casing 34 of the first main pump 33, and extends in the left-right direction parallel to the axis of the rotary shaft 36. The upstream passage 73 is formed as a flow passage extending between the pump casing 34 of the first main pump 33 and the gear casing 22. The upstream passage 73 connects the discharge pipe 34F of the pump casing 34 and the intermediate passage 74. Furthermore, the upstream passage 73 is located behind the first driven gear 27 in the gear casing 22, and at least a portion of the upstream passage 73 is formed at a position lower than the liquid level of the lubricating oil 32 (see FIG. 11).

[0091] The intermediate passage 74 is provided so as to extend laterally from the right end of the upstream passage 73 toward the front on the right wall portion 22A. Most of the intermediate passage 74 is disposed at a position lower than the liquid level of the lubricating oil 32 and closer to the gear chamber 23 than the outside (see FIG. 10). This allows the intermediate passage 74 to efficiently transfer heat from the lubricating oil 32 to the flowing hydraulic oil. In other words, the intermediate passage 74 can release heat from the lubricating oil 32 to the hydraulic oil.

[0092] The downstream passage 75 is located in front of the first driven gear 27 and the pump casing 34, and extends in the left-right direction parallel to the axis of the rotary shaft 36. The downstream passage 75 is formed as a flow passage extending between the gear casing 22 and the pump casing 34 of the first main pump 33. The right side of the downstream passage 75 is connected to the intermediate passage 74 by the right wall portion 22A, and the left side is connected to the sliding portion between the cradle 41 and the swash plate 42.

[0093] Furthermore, the downstream passage 75 is located in front of the first driven gear 27 in the gear casing 22, and is formed at a position lower than the liquid level of the lubricating oil 32. Furthermore, most of the downstream passage 75 is formed by passing through the passage forming portion 72.

[0094] The first oil pipeline 71 formed in this manner allows the hydraulic oil to flow sequentially through the upstream passage 73, the intermediate passage 74, and the downstream passage 75, thereby dissipating the heat of the lubricating oil 32 transmitted from the inner surface of the peripheral wall portion 22C of the gear casing 22, the inner surface of the right wall portion 22A, and the peripheral surface of the passage forming portion 72 to the hydraulic oil.

[0095] The external return pipe 76 connects the drain chamber 35 and the hydraulic oil tank 15 (see FIG. 12). The external return pipe 76 returns the hydraulic oil that has been supplied from the first oil pipe 71 to the sliding portion between the cradle 41 and the swash plate 42 and overflowed therefrom, as well as the hydraulic oil that has been supplied to other sliding portions, to the hydraulic oil tank 15 as excess hydraulic oil (drain oil) in the drain chamber 35.

[0096] Similar to the first oil line 71, the second oil line 77 serving as an oil line supplies the hydraulic oil (pressurized oil) discharged to the discharge line 34F provided in the rear casing 34C constituting the pump casing 34 of the second main pump 49 as lubricating oil to the sliding portion between the cradle 41 and the swash plate 42 via the gear chamber 23 of the gear casing 22. The hydraulic oil supplied to this sliding portion is returned to the hydraulic oil tank 15 together with excess hydraulic oil (drain oil) in the drain chamber 35.

[0097] The second oil pipe 77 is made up of passages built into the gear casing 22 and the pump casing 34, and a portion of it is immersed in the lubricating oil 32 in the gear chamber 23. The second oil pipe 77 transfers heat from the lubricating oil 32 to the circulating hydraulic oil. The second oil pipe 77 is configured to include a passage forming portion 78, an upstream passage 79, an intermediate passage 80, a downstream passage 81, and a return external pipe 82.

[0098] 11, the passage forming portion 78 is located below (directly below) the meshing portion 30 between the gear body 24B of the drive gear 24 and the gear body 28B of the second driven gear 28, and is formed to extend in the left-right direction across the right wall portion 22A and the left wall portion 22B. At least a portion of the passage forming portion 78, specifically, more than half of it, is immersed in the lubricating oil 32.

[0099] The passage forming portion 78 is formed as a triangular column with an apex near the meshing portion 30. The passage forming portion 78 includes an inner arc portion 78A that follows the tip circle of the gear body 24B of the drive gear 24, and an outer arc portion 78B that follows the tip circle of the gear body 28B of the second driven gear 28. The inner arc portion 78A is formed in a concave arc shape so as to follow the tip circle with a small gap from the gear body 24B. The outer arc portion 78B is formed in a concave arc shape so as to follow the tip circle with a small gap from the gear body 28B.

[0100] Therefore, the inner arcuate portion 78A can use a gap to restrict the amount of hydraulic oil that is scooped up by the gear body 24B and supplied to the meshing portion 30. Furthermore, the outer arcuate portion 78B can use a gap to restrict the amount of hydraulic oil that is scooped up by the gear body 28B and supplied to the meshing portion 30. As a result, the inner arcuate portion 78A and the outer arcuate portion 78B can reduce stirring resistance and further restrict the temperature rise of the lubricating oil 32.

[0101] The upstream passage 79 is disposed behind the gear casing 22 and the pump casing 34 of the second main pump 49, and extends in the left-right direction parallel to the axis of the rotary shaft 36. The upstream passage 79 is formed as a flow passage extending between the pump casing 34 of the second main pump 49 and the gear casing 22. The upstream passage 79 connects the discharge pipe 34F of the pump casing 34 and the intermediate passage 80.

[0102] Furthermore, in the position of the gear casing 22, the upstream passage 79 is located rearward of the second driven gear 28 and is formed at a position lower than the liquid level of the lubricating oil 32. Furthermore, most of the upstream passage 79 is formed by passing through the passage forming portion 78.

[0103] The intermediate passage 80 is provided so as to extend laterally from the right end of the upstream passage 79 toward the front on the right wall portion 22A. Most of the intermediate passage 80 is disposed at a position lower than the liquid level of the lubricating oil 32 and closer to the gear chamber 23 than the outside. This allows the intermediate passage 80 to efficiently transfer the heat of the lubricating oil 32 to the flowing hydraulic oil. In other words, the intermediate passage 80 can release the heat of the lubricating oil 32 to the hydraulic oil.

[0104] The downstream passage 81 is located in front of the second driven gear 28 and the pump casing 34, and extends in the left-right direction parallel to the axis of the rotary shaft 36. The downstream passage 81 is formed as a flow passage extending between the gear casing 22 and the pump casing 34 of the second main pump 49. The right side of the downstream passage 81 is connected to the intermediate passage 80 by the right wall portion 22A, and the left side is connected to the sliding portion between the cradle 41 and the swash plate 42. Furthermore, at the position of the gear casing 22, the downstream passage 81 is located in front of the second driven gear 28, and at least a portion of the downstream passage 81 is formed at a position lower than the liquid level of the lubricating oil 32 (see FIG. 11).

[0105] The second oil pipeline 77 formed in this manner, like the first oil pipeline 71, allows the hydraulic oil to flow sequentially through the upstream passage 79, the intermediate passage 80, and the downstream passage 81, thereby dissipating the heat of the lubricating oil 32 transmitted from the circumferential surface of the passage forming portion 78, the inner surface of the right wall portion 22A of the gear casing 22, and the inner surface of the circumferential wall portion 22C to the hydraulic oil.

[0106] The external return pipe 82 connects the drain chamber 35 and the hydraulic oil tank 15 (see FIG. 12). The external return pipe 82 returns the hydraulic oil that is supplied from the second oil pipe 77 to the sliding portion between the cradle 41 and the swash plate 42 and overflows, as well as the hydraulic oil that is supplied to other sliding portions, to the hydraulic oil tank 15 as excess hydraulic oil (drain oil) in the drain chamber 35.

[0107] In this embodiment, the suction pipe 83, the discharge pipe 84, and the return pipe 85 are pipes that circulate the hydraulic oil (pressurized oil) between the hydraulic oil tank 15, the fan pump 52, and the fan motor 14B of the cooling fan 14.

[0108] Thus, the second embodiment configured as described above can also achieve the same functions and effects as the first embodiment. In particular, in the second embodiment, the passage forming portion 72 of the first oil pipe 71 has an inner arc portion 72A that follows the tip circle of the gear body 24B of the drive gear 24, and an outer arc portion 72B that follows the tip circle of the gear body 27B of the first driven gear 27. Furthermore, the passage forming portion 78 of the second oil pipe 77 has an inner arc portion 78A that follows the tip circle of the gear body 24B of the drive gear 24, and an outer arc portion 78B that follows the tip circle of the gear body 28B of the second driven gear 28.

[0109] Therefore, the inner arcuate portions 72A, 78A and the outer arcuate portions 72B, 78B can use gaps to restrict the amount of hydraulic oil that is scooped up by the drive gear 24, the first driven gear 27, and the second driven gear 28 and supplied to the meshing portions 29, 30. This reduces the stirring resistance and further restricts the temperature rise of the lubricating oil 32.

[0110] Additionally, the first oil pipe 71 and the second oil pipe 77 are formed as passages in the gear casing 22 and the pump casing 34. This eliminates the need to provide additional piping or hoses, thereby reducing component and assembly costs.

[0111] In each embodiment, an example is described in which three pumps, namely, the first main pump 33, the second main pump 49, and the fan pump 52, are arranged side by side in the horizontal direction. However, the present invention is not limited to this, and may be configured such that, for example, two or four or more pumps are arranged side by side in the horizontal direction.

[0112] In addition, in each embodiment, the first main pump 33, the second main pump 49, and the fan pump 52 are configured as variable displacement swash plate hydraulic pumps. However, the present invention is not limited to this, and for example, a bent axis hydraulic pump may be used, or a hydraulic pump with a fixed displacement may also be used.

[0113] Furthermore, in each embodiment, an example has been described in which the pump device 21 according to the present invention is mounted on a hydraulic excavator 1. However, the present invention is not limited to this, and for example, the pump device 21 may be configured to be mounted on other construction machines such as a dump truck, a wheel loader, or a hydraulic crane. [Explanation of symbols]

[0114] 21 Pumping equipment 22 Gear casing 23 Gear room 24 Drive gear (gear) 27 First driven gear (gear) 28 Second driven gear (gear) 29,30 Meshing part 32 Lubricating oil 33 First main pump (hydraulic pump) 49 Second main pump (hydraulic pump) 52 Fan pump (hydraulic pump) 57 Oil pipe line 71 First oil pipe line (oil pipe line) 72,78 Passage forming part 72A, 78A Inner arc section (arc section) 72B, 78B Outer arc section (arc section) 77 Second oil pipe line (oil pipe line)

Claims

1. A gear casing with a gear chamber inside, a plurality of gears rotatably provided in the gear chamber; a lubricating oil stored in the gear chamber for lubricating meshing portions between the plurality of gears; a plurality of hydraulic pumps provided in the gear casing and rotating together with the gears to supply hydraulic oil to the hydraulic actuators; In a pump device comprising: An oil pipe is provided in the gear chamber, at least a portion of which is immersed in the lubricating oil, A pump device characterized in that the oil pipeline is configured to guide hydraulic oil discharged from any one of the plurality of hydraulic pumps.

2. 2. The pump device according to claim 1, The pump device is characterized in that the oil pipe is arranged at the position of the meshing portion between adjacent gears.

3. 2. The pump device according to claim 1, The pump device is characterized in that the oil pipe has an arc portion that follows the tip circle of the gear.

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