JP2002295638A - Transmission structure for work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission structure capable of reducing the size and costs of a work machine. SOLUTION: A recess part 29 is formed on a sidewall 28 in a transmission case 8, and a piston pump 30 and a piston motor 31 are housed in the recess part 29; and by having a port block 34, in which oil passages 32 and 33 connecting the piston pump 30 and the piston motor 31 together are formed, is connected to the sidewall 28 close the recess part 29, a hydrostatic continuously variable transmission device 9 is inserted into the inside of the transmission case 8. A hydraulic pump 21 arranged in the transmission case 8 is connected via a pressure reducing valve 44 to the hydrostatic continuously variable transmission device 9, to be used for charging it and is connected to an oil pressure circuit in a steering device 13 via a relief valve 23; and set pressure of the relief valve 23 is set to be higher than that of the pressure reducing valve 44, and returned oil of the relief valve 23 is supplied to the hydrostatic continuously variable transmission device 9 so as to be used as cooling oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power transmission from an engine to a left and right crawler type traveling device via a hydrostatic stepless transmission and a traveling transmission system provided in a transmission case. The present invention relates to a transmission structure of a working machine equipped with a hydraulic transmission device for switching the operating state of the left and right crawler traveling devices to steer the traveling vehicle body in a traveling transmission system.

[0002]

2. Description of the Related Art Conventionally, in a transmission structure of a working machine as described above, for example, as disclosed in Japanese Patent Application Laid-Open No. 11-220933, a transmission device is installed in a transmission case with a traveling transmission system and the like. And a hydrostatic stepless transmission separately configured to this transmission device is communicatively connected,
Power after shifting by the hydrostatic continuously variable transmission is transmitted to the transmission.

[0003]

However, according to the above prior art, since the hydrostatic stepless transmission and the transmission are separately constructed and connected, the manufacturing cost increases and the hydrostatic stepless transmission is increased. Since the entire transmission including the step transmission and the transmission has become larger, there is room for improvement in reducing the size and cost of the working machine.

An object of the present invention is to provide a power transmission structure capable of reducing the size and cost of a working machine.

[0005]

[Means for Solving the Problems] [Structure] In order to achieve the above object, according to the first aspect of the present invention, power from an engine is supplied to a hydrostatic continuously variable transmission and a transmission case. The hydraulic transmission is transmitted to the left and right crawler-type traveling devices via the traveling transmission system, and the operating state of the left and right crawler-type traveling devices is switched to the traveling transmission system to steer the traveling body. In the transmission structure of a working machine equipped with a directional device, a recess is formed in a side wall of the transmission case, a piston pump and a piston motor are housed in the recess, and an oil passage connecting the piston pump and the piston motor is formed. By connecting the formed port block to the side wall and closing the recess, the hydrostatic stepless transmission can be inserted into the transmission case. The hydraulic pump mounted on the transmission case is connected to the hydrostatic stepless transmission via a pressure reducing valve for charging, and connected to a hydraulic circuit of the steering device via a relief valve, The pressure of the relief valve is set to be higher than the pressure of the pressure reducing valve, and the return oil of the relief valve is supplied to the hydrostatic continuously variable transmission for cooling.

According to the first aspect of the present invention, since the side wall of the transmission case is effectively used for the casing of the hydrostatic continuously variable transmission, the number of parts can be reduced. The casing of the hydrostatic continuously variable transmission can be molded with a mold for molding the side wall of the transmission case without requiring a dedicated mold for molding the casing of the hydrostatic continuously variable transmission. As a result, it is possible to reduce the manufacturing cost and make it advantageous in terms of parts management.

In addition, since the hydrostatic stepless transmission enters the inside of the transmission case, the size of the transmission can be reduced as a whole, and the side wall of the transmission case can be mounted on the side of the transmission case. Although it is effectively used for the casing, maintenance of the traveling transmission system and the like installed in the transmission case can be performed without disassembling the hydrostatic continuously variable transmission.

In addition, a single hydraulic pump is used for charging the hydrostatic continuously variable transmission and for operating the steering device.
Since it is configured to also serve to cool the hydrostatic continuously variable transmission, it is possible to simplify the hydraulic circuit and reduce manufacturing costs, and to effectively cool the hydrostatic continuously variable transmission. Become like

[Effect] Therefore, the working machine can be reduced in size and cost, and it can be made advantageous in terms of parts management and maintenance. Further, the hydraulic circuit can be simplified while the hydraulic circuit can be simplified. The cooling of the step transmission can be effectively performed.

[Structure] According to a second aspect of the present invention, in the first aspect, the return oil of the pressure reducing valve is supplied to the hydrostatic continuously variable transmission for cooling. Configured.

According to the second aspect of the invention, in addition to the return oil from the relief valve on the steering device side, the return oil from the pressure reducing valve on the hydrostatic continuously variable transmission device is also cooled. Since the cooling oil is supplied to the hydrostatic continuously variable transmission, the supply of the cooling oil to the hydrostatic continuously variable transmission can be performed more stably.

[Effect] Accordingly, the cooling of the hydrostatic continuously variable transmission can be performed more effectively.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall side view of a self-removing combine which is an example of a working machine. The combine is a traveling machine body 2 driven by a pair of left and right crawler traveling devices 1. At the front of the hull, a harvesting and transporting device 3 that cuts and transports planted grain culm and transports it rearward is connected so as to be able to move up and down. And a grain tank 5 for storing the grains from the threshing apparatus 4, and a boarding operation unit 6 is formed at a location in front of the grain tank 5.

As shown in FIGS. 2 to 8, the combine uses the power from the engine 7 to apply a belt tension to a hydrostatic continuously variable transmission 9 mounted on the upper left front of a transmission case 8 located on the left front of the combiner. Power transmitted through a main clutch 10 of the type, and the power after shifting by the hydrostatic stepless transmission 9 is transmitted via a traveling transmission system 11 installed in the lower half of the transmission case 8 to the left and right crawler type. The transmission is transmitted to the traveling device 1. By operating a main transmission lever (not shown) linked to the hydrostatic continuously variable transmission 9, switching between forward and backward movement and continuously variable transmission can be performed. ing.

The traveling power transmission system 11 controls the traveling machine body 2 by switching the operating state of a gear type transmission 12 to which power from a hydrostatic type continuously variable transmission 9 is transmitted and the left and right crawler type traveling devices 1. The hydraulic power steering device 13 and the like are provided. By operating an auxiliary shift lever (not shown) linked to the gear type transmission 12, power after shifting by the hydrostatic stepless transmission 9 is transmitted. The gear can be shifted in two steps.

As shown in FIGS. 2 to 9, the steering device 13 includes:
Crawler type traveling device 1 corresponding to gear type transmission 12
Left and right claw clutches 14 for intermittent transmission of power to the crawler-type traveling device 1
5. Left and right hydraulic cylinders 17 that enable the corresponding claw clutch 14 to be disengaged against the bias of the spring 16 and the braking operation of the multiple disc brake 15, and left and right crawlers against the bias of the spring 18. It is constituted by a multi-plate type hydraulic clutch 20 that enables connection of the drive shafts 19 in the traveling device 1.

The operation state of the steering device 13 can be switched by adjusting the flow rate of mission oil pumped by the hydraulic pump 21 as hydraulic oil for the left and right hydraulic cylinders 17 and the hydraulic clutch 20. Can be performed by controlling the operation of the relief valve 23, the switching valve 24, the variable relief valve 25, and the pressure reducing valve 26 interposed in the steering oil passage 22.
The operation can be performed by operating an operation lever 27 linked to the switching valve 24 and the variable relief valve 25. Switching valve 24
When the operating lever 27 is operated to the neutral position N, the operating lever is switched to a neutral state in which the supply of hydraulic oil to the left and right hydraulic cylinders 17 is prevented and the discharge of hydraulic oil from the left and right hydraulic cylinders 17 is permitted. 27 from the first turning position L1, R1 on either side to the second turning position L2, R
When the operation is performed within the turning operation area extending over two directions, either the left or right of allowing the supply of the hydraulic oil to the hydraulic cylinder 17 corresponding to the operation direction and the discharge of the hydraulic oil from the hydraulic cylinder 17 opposite to the operation direction is permitted. The turning state can be switched. Variable relief valve 25
When the operating lever 27 is operated to the neutral position N or the left or right first turning position L1 or R1, the relief pressure becomes zero, and the left or right first turning position L1 or R1 shifts to the second turning position L2 or R2. The relief pressure is set to increase as the operation is increased to the side.

With this configuration, when the operating lever 27 is operated to the neutral position N, the switching valve 24 is switched to the neutral state, whereby the hydraulic oil is discharged from the left and right hydraulic cylinders 17 and the left and right The engaged state of the claw clutch 14 and the non-braking state of the left and right multiple disc brakes 15 appear.
In addition, since the hydraulic oil is supplied to the hydraulic clutch 20 and the engaged state of the hydraulic clutch 20 that connects the drive shafts 19 of the left and right crawler traveling devices 1 appears, the left and right crawler traveling devices 1 are used. It is designed to show a straight-ahead state driven at high speed.

When the operating lever 27 is operated from the neutral position N to the first turning position L1 on the left side, the switching valve 24 is switched to the left turning state, whereby hydraulic oil is supplied to the left hydraulic cylinder 17 and the left pawl clutch After the cut-off state of No. 14 appears, the relief pressure of the variable relief valve 25 remains zero, so that the hydraulic oil supplied to the left hydraulic cylinder 17 is directly discharged from the discharge oil passage portion and Since the multi-disc brake 15 is maintained in the non-braking state, the left crawling traveling state appears in which the left crawler traveling apparatus 1 is driven while the right crawler traveling apparatus 1 is driven. When the switch 27 is operated from the neutral position N to the first turning position R1 on the right side, the switching valve 24 is switched to the right turning state, whereby hydraulic oil is supplied to the right hydraulic cylinder 17 and After the cut-off state of the switch 14 appears, the relief pressure of the variable relief valve 25 remains zero, so that the hydraulic oil supplied to the right hydraulic cylinder 17 is discharged from the drain oil passage portion as it is. Since the right multiple disc brake 15 is maintained in the non-braking state, the right crawler traveling device 1 is driven, while the right crawler traveling device 1 is driven. ing.

In the left and right gentle turning state, the internal pressure on the inlet side of the pressure reducing valve 26 is reduced in accordance with the appearance thereof, so that the hydraulic oil in the hydraulic clutch 20 is discharged. As a result, the hydraulic clutch 20 is gradually switched to the disengaged state, and the transmission from the driven crawler type traveling device 1 to the driven crawler type traveling device 1 is gradually weakened. The transition from the state to the gentle turning state can be smoothly performed.

When the operating lever 27 is moved to the left first turning position L1.
, The relief pressure of the variable relief valve 25 increases as the amount of operation increases, so that hydraulic oil is supplied to the left hydraulic cylinder 17 and the left multi-plate Since the brake 15 is gradually switched to the braking state, a sharp left turning state in which the right crawler-type traveling device 1 is driven while the left crawler-type traveling device 1 is braked can appear smoothly. To
When the operation lever 27 is operated from the first turning position R1 on the right side to the second turning position R2, the relief pressure of the variable relief valve 25 increases as the operation amount increases. And the right multi-plate brake 15 is gradually switched to the braking state, so that the left crawler traveling device 1 is driven while the right crawler traveling device 1 is braked. Can appear smoothly.

Although not shown, the right multiple disc brake 1
Reference numeral 5 is linked to a brake pedal together with the main clutch 10, and when the brake pedal is depressed, the main clutch 10 cuts off transmission from the engine 7 to the hydrostatic continuously variable transmission 9, and the multiple disc brake 15 can show a traveling stop state in which the left and right crawler-type traveling devices 1 are braked via the steering device 13. By holding the brake pedal in the depressed operation position with the lock fitting, the multi-disc brake 15 Can function as a parking brake to show a parking state.

As shown in FIGS. 2 to 8, the transmission case 8 has a two-part structure that can be separated into right and left. Recess 29 is formed. The hydrostatic stepless transmission 9 includes an axial piston pump 30 and a piston motor 3 in a recess 29 of the transmission case 8.
1 and the piston pump 30 and the piston motor 3
1 is connected to a left side wall 28 and formed with a forward oil passage 32 and a reverse oil passage 33 that connect to the left side wall 28 to close the recess 29.

That is, by effectively utilizing the side wall 28 of the transmission case 8 for the casing of the hydrostatic continuously variable transmission 9, the number of parts and the manufacturing cost can be reduced. The use of the hydrostatic stepless transmission 9 allows the hydrostatic stepless transmission 9 to largely enter the inside of the transmission case 8 and reduce the space required for disposing them. Therefore, the size of the entire combine can be reduced, and the port block 34, which easily rises in temperature by having the high-pressure oil passages 32 and 33, is located outside the transmission case 8, so that the port block 34 Heat can be promoted, and an increase in oil temperature can be suppressed.

In addition, while the sidewall 28 of the transmission case 8 is effectively used for the casing of the hydrostatic stepless transmission 9, the hydrostatic stepless transmission 9 is constructed by being externally assembled to the transmission case 8. Because it is possible, it is possible to facilitate the assembly of the hydrostatic stepless transmission 9 to the transmission case 8 and to perform maintenance of the hydrostatic stepless transmission 9 without disassembling the transmission case 8. Since the maintenance of the traveling transmission system 11 and the like provided in the transmission case 8 can be performed without disassembling the hydrostatic continuously variable transmission 9, maintenance performance can be improved.

At the rear upper portion of the transmission case 8, a piston pump 3 serving as an input shaft 35 of the hydrostatic continuously variable transmission 9 is provided.
A transmission line 37 for work transmitted from an input shaft 35 of the transmission unit 3 is provided, and a belt tension is applied between an output shaft 38 of the transmission shaft 37 and an input shaft 39 of the reaper 3 disposed above a rear part of the transmission case 8. A reaping clutch 40 is provided. The work transmission system 37 uses the power from the engine 7 at a work speed suitable for medium-to-low speed traveling by the operation of a work lever (not shown) associated therewith.
And a high-speed transmission state in which the reaper 3 is driven at a work speed suitable for high-speed traveling.
It is configured so that the speed can be changed to a step, and by displaying the driving state of the cutting and conveying device 3 suitable for the traveling speed, it is possible to perform suitable cutting and conveying of the planted grain culm.

The trunnion shaft 4 of the hydrostatic continuously variable transmission 9
The extension 1 extends forward from the front wall 28 of the transmission case 8 so as to be located forward of the output shaft 38 of the working transmission system 37. For example, as shown in FIGS. 2 to 4, the input shaft 39 of the reaper transport device 3 is located on the right side of the transmission case 8, and as shown in FIG. In any case where the input shaft 39 of the device 3 is located, the reaping clutch 40 is connected to the output shaft 38 of the working transmission system 37 and the input of the reaping conveyance device 3 without hindering the linkage mechanism 42 extending from the main transmission lever to the trunnion shaft 41. It can be easily installed over the shaft 39.

As shown in FIG. 9, the hydraulic oil from the hydraulic pump 21 is also supplied to the hydrostatic continuously variable transmission 9 via a charging oil passage 43. The oil passage 43 includes a pressure reducing valve 44 and a check valve 4 for the forward oil passage 32.
5 and a check valve 46 for the reverse oil passage 33 are interposed. The pressure reducing valve 44 is set so that its set pressure is lower than the set pressure of the relief valve 23 for steering.
The return oil from the pressure reducing valve 44 is supplied to the hydrostatic continuously variable transmission 9 for cooling together with the return oil from the relief valve 23 for steering.

That is, since the single hydraulic pump 21 is configured to serve both for charging and cooling of the hydrostatic type continuously variable transmission 9 in addition to the operation of the steering device 13, The hydraulic circuit can be simplified and the manufacturing cost can be reduced. In addition, the return oil from the relief valve 23 for steering and the return oil from the pressure reducing valve 44 for charging are used as a cooling stepless hydrostatic stepless. Since the oil is supplied to the transmission 9, the cooling oil can be stably supplied to the hydrostatic continuously variable transmission 9, so that the cooling of the hydrostatic continuously variable transmission 9 can be effectively performed. Has become.

As shown in FIGS.
Is a trochoid pump driven by an input shaft 47 of a working transmission system 37. A pump block 48 is provided at a rear upper portion of the left side wall 28 of the transmission case 8 equipped with the hydrostatic continuously variable transmission 9. It is composed by connecting. In other words, since the side wall 28 of the transmission case 8 is effectively used for the hydraulic pump 21, the number of parts can be reduced and the manufacturing cost can be reduced. Since it is a rear upper portion of the side wall 28 of the transmission case 8 which is recessed due to the provision of the transmission 9, the pump block 48 is connected to the side wall 28 to form the hydraulic pump 21. In addition, the size increase due to the protrusion can be avoided, and the hydrostatic type continuously variable transmission 9 and the charge / cooling hydraulic pump 21
Are installed on the same side wall 28 so that their oil passages 2
Connection via the terminals 2 and 43 can be easily performed.

As shown in FIG. 6, a transmission gear 4 of a steering device 13 disposed in a lower portion of the transmission case 8 is provided in the transmission case 8.
A partition wall 51 is formed near the bottom of the transmission case 8 for partitioning a storage unit 50 for storing the transmission oil jumped up by the transmission oil 9 or the like.
The transmission oil stored in the transmission is supplied to the hydrostatic continuously variable transmission 9 and the steering device 13 via the oil filter 52. The return oil from the hydrostatic continuously variable transmission 9 and the steering device 13 is returned to the storage unit 50.

In other words, by using the mission oil as the working oil, there is no need to separately provide an oil tank dedicated to the working oil, so that the manufacturing cost can be reduced and the space can be saved. Device 13
The transmission oil stirred by the transmission gear 49 or the like is not supplied as it is to the hydrostatic continuously variable transmission 9 or the like, but is once jumped up by the transmission gear 49 and then flows down along the partition wall 51 or the like. The mission oil in the storage unit 50 from which air bubbles are removed by being stored in the storage unit 50 is supplied to the hydrostatic continuously variable transmission 9 or the like,
In addition, since return oil from the hydrostatic stepless transmission 9 or the steering device 13 from which bubbles have been removed is returned to the storage unit 50, the transmission oil in the storage unit 50 contains bubbles. The ratio can be further reduced, and the possibility that air bubbles mixed in the hydraulic oil adversely affect the hydrostatic continuously variable transmission 9 and the like can be more effectively suppressed.

[Other Embodiments] Hereinafter, other embodiments of the present invention will be listed. (1) The working machine may be a ginseng harvester, a radish harvester, or the like. (2) As shown in FIG. 10, the side wall 28 of the transmission case 8 is bulged outward from the transmission case 8 to form a recess 29, and an axial piston pump 30 and a piston motor 31 are formed in the recess 29. A port block 34 in which a forward oil passage 32 and a backward oil passage 33 for connecting the piston pump 30 and the piston motor 31 are formed is connected to the side wall 28 from inside the transmission case 8 to form the recess 29. May be closed so that the port block 34 is located inside the transmission case 8 with the hydrostatic continuously variable transmission 9 inserted inside the transmission case 8. . (3) Only the return oil from the steering relief valve 23 may be supplied to the hydrostatic continuously variable transmission 9 for cooling.

[Brief description of the drawings]

FIG. 1 is an overall side view of a combine.

FIG. 2 is a schematic diagram showing a transmission configuration of a combine.

FIG. 3 is a longitudinal sectional front view of a transmission case.

FIG. 4 is a vertical sectional front view of an upper portion of a transmission case.

FIG. 5 is a vertical sectional front view of a lower portion of a transmission case.

FIG. 6 is a longitudinal sectional side view of a transmission case.

FIG. 7 is a side view of a transmission case.

FIG. 8 is a side view of a main part showing a transmission configuration.

FIG. 9 is a hydraulic circuit diagram

FIG. 10 is a vertical front view of an upper portion of a transmission case showing another embodiment of the hydrostatic continuously variable transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crawler type traveling device 2 Traveling body 7 Engine 8 Transmission case 9 Hydrostatic stepless transmission 11 Traveling transmission system 13 Steering device 21 Hydraulic pump 23 Relief valve 28 Side wall 29 Depression 30 Piston pump 31 Piston motor 32 Oil passage 33 Oil passage 34 Port block 44 Pressure reducing valve

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Tomonori Hita 64, Ishizukita-cho, Sakai City, Osaka Prefecture Inside the Kubota Sakai Plant (72) Inventor, Minoru Hiraoka 64, Ishizukitamachi, Sakai City, Osaka Prefecture Kubota Sakai Manufacturing In-house (72) Inventor Masayoshi Nakata 64 Ishizu-Kitacho, Sakai-shi, Osaka F-term in Kubota Sakai Works Co., Ltd. (Reference)

Claims (2)

[Claims] 1. The power from an engine is transmitted to a left and right crawler type traveling device via a hydrostatic continuously variable transmission and a traveling transmission system provided in a transmission case.
The traveling transmission system, a transmission structure of a working machine equipped with a hydraulic steering device that switches the operating state of the left and right crawler traveling devices to steer the traveling aircraft, wherein Forming a recess, accommodating a piston pump and a piston motor in the recess, and connecting a port block formed with an oil passage connecting the piston pump and the piston motor to the side wall to close the recess; The hydrostatic stepless transmission is configured to be inserted into the inside of the transmission case, and a hydraulic pump mounted on the transmission case is connected to the hydrostatic stepless transmission via a pressure reducing valve. Connected for charging and connected to the hydraulic circuit of the steering device via a relief valve, the set pressure of the relief valve is higher than the set pressure of the pressure reducing valve Uni set, transmission structure of the working machine is arranged to supply return oil of the relief valve for cooling the hydrostatic continuously variable transmission. 2. The transmission structure of a working machine according to claim 1, wherein the return oil of said pressure reducing valve is supplied to said hydrostatic continuously variable transmission for cooling.