JP2002295635A - Transmission structure for harvester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission structure capable of reducing the size and cost of a work machine. SOLUTION: In this transmission structure for a harvester, power from an engine 7 is transmitted to a traveling device 1 via a hydrostatic continuously variable transmission device 9 and a traveling transmission system 11 built in a transmission case 8, while being transmitted to a harvesting device 3 via working transmission system 37; a recess part 29 is formed on a sidewall 28 in the transmission case 8, and a piston pump 30 and a piston motor 31 are housed in the recess part 29. When 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 to close the recess part 29, the hydrostatic continuously variable transmission device 9 is inserted into the inside of the transmission case 9; and while a trunnion shaft 41 in the hydrostatic continuously variable transmission device 9 moves from a neutral position to a predetermined advanced side low-speed position, transmission to the traveling device 1 and the harvesting device 3 is prevented by means of a reining mechanism 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transmitting power from an engine to a traveling device via a hydrostatic continuously variable transmission and a traveling transmission system provided in a transmission case. The present invention relates to a transmission structure of a harvester that is configured to be transmitted to a harvesting device via a transmission device.

[0002]

2. Description of the Related Art Conventionally, in a transmission structure of a harvester as described above, for example, as disclosed in Japanese Patent Application Laid-Open No. H11-220933, 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. In the transmission structure of the harvester configured to transmit to the traveling device via the traveling transmission system and to the harvesting device via the work transmission system, a recess is formed in a side wall of the transmission case, By accommodating a piston pump and a piston motor in the recess and connecting a port block having an oil passage connecting the piston pump and the piston motor to the side wall to close the recess, the hydrostatic pressure is reduced. The continuously variable transmission is configured to be inserted into the inside of the transmission case, and the trunnion shaft of the hydrostatic continuously variable transmission is shifted from the neutral position to a predetermined forward low speed position. During up to, equipped with a restraint mechanism for preventing the transmission to the traveling device and the harvesting arrangement.

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, the operation of the restraint mechanism causes the harvesting device to be driven at a low speed with the low-speed running, and the speed difference caused by the harvesting device being driven at a constant relatively high speed regardless of the low-speed running. As a result, it is possible to avoid the occurrence of poor harvesting or poor transport.

[Effect] Accordingly, a power transmission structure which can reduce the size and cost of the working machine, can be advantageous in terms of parts management and maintenance, and can suitably harvest and transport the crop to be harvested. Now you can.

[Structure] According to a second aspect of the present invention, in the first aspect of the present invention, a release mechanism for releasing the transmission inhibition by the traction mechanism is provided.

According to the second aspect of the present invention, during non-working running without performing harvesting work, zero starting and very low speed running can be performed by releasing the transmission inhibition by the traction mechanism by the release mechanism. become.

[Effects] Accordingly, it is possible to improve the traveling performance during non-work traveling.

According to a third aspect of the present invention, in accordance with the second aspect of the present invention, the traction control mechanism is operated in conjunction with a disengagement operation of a work clutch for interrupting transmission to the harvesting device. So that the transmission blocking by
The work clutch and the release mechanism are linked.

According to the third aspect of the present invention, when the transmission to the harvesting device is turned off by disengaging the work clutch, the transmission is prevented from being inhibited by the traction mechanism without the need to manually operate the release mechanism. The vehicle can be released, and the vehicle can be started at zero speed or run at very low speed.

[Effects] Accordingly, it is possible to improve the traveling performance during non-work traveling while improving the operability.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall side view of a self-removing combine as an example of a harvester. This combine operates a pair of left and right crawler-type traveling devices 1 as an example of a traveling device. At the front of the traveling machine body 2 that travels, a harvesting and conveying device 3, which is an example of a harvesting device that cuts the planted grain culm and conveys it rearward, is connected to the traveling machine body 2 so as to be able to move up and down.
A threshing device 4 that receives the harvested grain culm from the harvesting and transporting device 3 and performs threshing and sorting processing, and a grain tank 5 that stores grains from the threshing device 4 are mounted.
Is formed by forming the boarding operation section 6 at a location in front of the vehicle.

As shown in FIGS. 2 to 8, the combine uses a belt tension to transfer the power from the engine 7 to a hydrostatic continuously variable transmission 9 mounted on the upper left front of a transmission case 8 located on the left front. 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 transmission system 11 controls the traveling machine body 2 by switching the operating state of a gear type transmission 12 to which the power from the hydrostatic stepless 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.

Switching of the operating state of the steering device 13 can be performed 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 operation lever 27 is operated to the neutral position N, the switching valve 24 is switched to the neutral state, whereby the operating oil is discharged from the left and right hydraulic cylinders 17 and the left and right hydraulic cylinders 17 are discharged. 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, a slow left turning state in which the left crawler traveling device 1 is driven while the right crawler traveling device 1 is driven appears. 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 at 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.

The operation 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 continuously variable transmission 9 makes it possible for the hydrostatic continuously variable 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 continuously variable transmission 9, the hydrostatic continuously variable transmission 9 is constructed by assembling the transmission case 8 from outside. Because of this, 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 installed in the transmission case 8 can be performed without disassembling the hydrostatic continuously variable transmission 9, the maintainability can be improved.

The input shaft 35 of the piston pump 30 serving as the input shaft 35 of the hydrostatic continuously variable transmission 9 is equipped with a cooling fan 36 for supplying cooling air to the port block 34, The port block 34 can be effectively cooled, and the oil temperature can be efficiently reduced.

In the upper rear portion of the transmission case 8, a working transmission system 37 transmitted from the input shaft 35 of the hydrostatic continuously variable transmission 9 is provided, and an output shaft 38 and a rear portion of the transmission case 8 are provided. A belt tension type reaping clutch 40, which is an example of a work clutch, is provided between the reaper and the input shaft 39 of the reaper transporting device 3 disposed above. The work transmission system 37 is operated by operating a work lever (not shown) associated therewith. The power from the engine 7 is used to drive the reaping conveyance device 3 at a work speed suitable for medium to low speed travel, and a high speed travel state. The speed can be changed to two stages: a high-speed transmission state in which the cutting and conveying device 3 is driven at a work speed suitable for the occasion. Suitable cutting and transporting of the culm can be performed.

The trunnion shaft 4 of the hydrostatic continuously variable transmission 9
1 extends forward from the upper front part of the transmission case 8 so as to be located forward of the output shaft 38 of the working transmission system 37, whereby, for example, the configuration of the reaper transport device 3 As shown in FIGS. 2 to 4,
The input shaft 3 of the reaper 3 is provided on the right side of the transmission case 8.
9 and the input shaft 39 of the reaper 3 is located on the left side of the transmission case 8 as shown in FIG. 10, as shown in FIG. The reaping clutch 40 can be easily bridged between the output shaft 38 of the working transmission system 37 and the input shaft 39 of the reaper transporting device 3 without any hindrance to the linking mechanism 42 extending over 41.

As shown in FIG. 9, a charging oil passage 43 for the hydrostatic continuously variable transmission 9 is connected to an oil passage portion on the upper side of the hydraulic pump 21 in the steering oil passage 22. The oil passage 43 includes a charge hydraulic pump 44, a check valve 45 for the forward oil passage 32, and a reverse oil passage 3.
Check valve 46 for 3 and neutral valve 4 for forward oil passage 32
7, a relief valve 48 is interposed, and the return oil from the relief valve 48 is supplied to the hydrostatic continuously variable transmission 9 for cooling.

As shown in FIGS. 2 to 8, the steering hydraulic pump 21 and the charging hydraulic pump 44 are trochoid double pumps driven by the input shaft 49 of the working transmission system 37. A pump block 50 containing a relief valve 48 is connected to an upper rear portion of the left side wall 28 of the transmission case 8 equipped with the hydraulic type continuously variable transmission 9. In other words, since the side wall 28 of the transmission case 8 is effectively used for the hydraulic pumps 21 and 44, the number of parts can be reduced and the manufacturing cost can be reduced. The hydraulic pumps 21 and 44 are configured by connecting the pump block 50 to the rear upper portion of the side wall 28 of the transmission case 8 which is recessed due to the provision of the continuously variable transmission 9. While being
It is possible to avoid an increase in size due to the protrusion, and to equip the same side wall 28 with the hydrostatic stepless transmission 9, a hydraulic pump 44 for charging and a relief valve 48 for cooling. From those oil passages 22,
The connection via 43 can be easily performed.

As shown in FIGS. 9, 11 and 12, the trunnion shaft 41 of the hydrostatic continuously variable transmission 9 is linked to a neutral valve 47 for the forward oil passage 32 via a check mechanism 51. The restraining mechanism 51 includes a sector gear 5 integrally formed with an operation arm 52 mounted on the trunnion shaft 41.
3, a pinion gear 54 that meshes with the sector gear 53, a cam 55 that rotates integrally with the pinion gear 54, and the like. The cam 55 is connected to the trunnion shaft 41
During the period from the neutral position to the predetermined low-speed position, the neutral valve 47 is switched from the shut-off state to the communicating state against the pilot pressure. A sliding member 57 is provided between the transmission case 8 and the cam 55 to allow the cam 55 to move between an operation position acting on the neutral valve 47 and a non-operation position not acting. Member 5
7 is a cam 55 which is linked with the operation of engaging the reaping clutch 40.
Is linked to the reaping clutch 40 such that the cam 55 is located at the non-operating position in conjunction with the cutting operation of the reaping clutch 40.

With this configuration, during the work traveling in which the engagement operation of the mowing clutch 40 is performed, the trunnion is operated by the operation of the restraint mechanism 51 as shown in FIGS. 11, 12A and 13A. Until the shaft 41 reaches the predetermined forward low speed position from the neutral position, the hydrostatic continuously variable transmission 9
Stops operating and the crawler-type traveling device 1 and the reaper transport device 3
Owing to the speed difference at which the reaping and conveying device 3 is driven at a relatively constant speed at a relatively high speed irrespective of low-speed running, the occurrence of poor harvesting or poor transporting occurs. And the reaping clutch 40
During the non-working travel in which the cutting operation is performed, as shown in (b) of FIG. 12, the operation stop of the hydrostatic stepless transmission 9 by the restraint mechanism 51 causes the sliding member 57 functioning as a release mechanism thereof When the vehicle is traveling in reverse, the neutral valve 47 does not function as shown in FIG. 9, so that the vehicle can perform zero-start and very low-speed traveling as shown in FIG. You can make it.

As shown in FIG. 6, a transmission gear 5 of a steering device 13 disposed below the transmission case 8 is disposed in the transmission case 8.
In the vicinity of the bottom of the transmission case 8, a partition wall 60 is provided which defines a storage section 59 for storing the transmission oil splashed up by the transmission case 8 or the like.
The transmission oil stored in the hydraulic pump is supplied to the hydrostatic continuously variable transmission 9 and the steering device 13 via the oil filter 61. Further, return oil from the hydrostatic continuously variable transmission 9 or the steering device 13 is returned to the storage portion 59.

In other words, since the transmission oil is used as the working oil, it is not necessary 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 58 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 58 and then flows down along the partition wall 60 or the like. Supplying the mission oil in the storage unit 59 from which bubbles are removed by being stored in the storage unit 59 to the hydrostatic continuously variable transmission 9 and the like,
In addition, since return oil from the hydrostatic stepless transmission 9 or the steering device 13 from which bubbles are already removed is returned to the reservoir 59, the transmission oil in the reservoir 59 contains bubbles. The ratio can be further reduced, and the possibility that air bubbles mixed into the hydraulic oil adversely affect the hydrostatic continuously variable transmission 9 and the like can be more effectively suppressed.

[Other Embodiments] Other embodiments of the present invention will be listed below. (1) The harvester may be a ginseng harvester, a radish harvester, or the like. (2) As shown in FIG. 14, the side wall 28 of the transmission case 8 is bulged outwardly of 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) A dedicated operation tool for operating the release mechanism 57 may be provided without linking the mowing clutch 40 and the release mechanism 57.

[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 positional relationship between the trunnion shaft and the cutting clutch.

FIG. 9 is a hydraulic circuit diagram

FIG. 10 is a vertical front view of the upper portion of the transmission case showing a state in which a mowing clutch is disposed on the left side of the transmission case.

11A is an operation diagram showing an operation state of a traction mechanism at a neutral position. FIG. 11B is an operation diagram showing an operation state of a traction mechanism at a predetermined forward low-speed position. Action diagram showing operating state

12A is an operation diagram showing the operation state of the release mechanism when the work clutch is engaged (B) is an operation diagram showing the operation state of the release mechanism when the work clutch is released

13A is a diagram showing the relationship between the traveling speed and the cutting and conveying speed in the state where the restraining mechanism is operating.

FIG. 14 is a longitudinal sectional 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 Traveling device 3 Harvesting device 7 Engine 8 Transmission case 9 Hydrostatic continuously variable transmission 11 Traveling transmission system 28 Side wall 29 Depression 30 Piston pump 31 Piston motor 32 Oil passage 33 Oil passage 34 Port block 37 Work transmission system 40 Work Clutch 41 Trunnion shaft 51 Restriction mechanism 57 Release mechanism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60K 17/06 B60K 17/06 E 17/10 17/10 EF 17/28 17/28 C (72) Inventor Tomonori Hita 64 Ishizukita-cho, Sakai-shi, Osaka, Japan, inside Kubota Sakai Works, Ltd. 64 Ishizu-Kitamachi, Sakai City F-term in Kubota Sakai Works (reference) 2B076 AA03 BA03 DA02 DA04 DA15 DD05 EC19 ED30 3D039 AA02 AA03 AA04 AB13 AB22 AC05 AC21 AC37 AC40 AC65 AC67 AC68 AC70 AC77 AD02 AD06 AD25 AD44 AD54 3D042 AA01 AA05 AA06 AB10 AB11 BA02 BA05 BA07 BA08 BA12 BA13 BA16 BA18 BA19 BA20 BB02 BB03 BC02 BC07 BC08 BC09 BC13 BC15 BC17 BD04 BD08 BD09 3D043 AA01 AA05 AA06 AB10 AB11 BA06 BC03 BC05 B C06 BC09 BC11 BC14 BC19 BD03 BE03 BF03 BF07 BF08

Claims (3)

[Claims] 1. The power from an engine is transmitted to a traveling device via a hydrostatic continuously variable transmission and a traveling transmission system built in a transmission case, and transmitted to a harvesting device via a work transmission system. A transmission structure for a harvester, wherein 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 the oil connects the piston pump and the piston motor. By connecting a port block formed with a path to the side wall and closing the recess, the hydrostatic stepless transmission is configured to be inserted into the inside of the transmission case,
A harvester equipped with a restraint mechanism that prevents transmission to the traveling device and the harvesting device until the trunnion shaft of the hydrostatic continuously variable transmission reaches a predetermined forward low-speed position from a neutral position. Transmission structure. 2. The transmission structure of a harvester according to claim 1, further comprising a release mechanism for releasing the transmission inhibition by the restraint mechanism. 3. The work clutch and the release mechanism are linked so that transmission inhibition by the restraint mechanism is released in conjunction with a work clutch disengagement operation for interrupting transmission to the harvesting device. The transmission structure of the harvester according to claim 2.