Combine harvester

Abstract

Provided is a transmission 23 in which: output rotation of an engine 22 is transmitted from an output shaft 24 of a continuously variable transmission 20 to a first shaft 29, a second shaft 32, and a third shaft 26 of the transmission 23 through an input shaft 25 of the transmission 23; the first shaft 29 is provided with a first gear 30 always engaged with a gear 27 of the input shaft 25, a second gear 43, and a clutch 48 that rotates integrally with the first shaft 29 between the first gear 30 and the second gear 43; the second shaft 32 is provided with a third gear 46 always engaged with the first gear 30, a fourth gear 45 always engaged with the second gear 43, and a fifth gear 47 that transmits rotation to the third shaft 26; the first gear 30 is provided with an engaging part 50 engaged with an engaging part 48A of the clutch 48; and the second gear 43 is provided with an engaging part 51 engaged with an engaging part 48B of the clutch 48. Thus, the transmission 23 transmits the output to a reaping device 4 while suppressing transmission loss in the output.

Description

Combine

[0001] The present invention relates to a combine.

[0002] Conventionally, the rotation of a continuously variable transmission is input to an input shaft, and the output rotation transmitted to the input shaft is transmitted to a counter shaft via the gears of the input shaft, the main cutting shaft, and the counter shaft. A configuration in which the rotation transmitted to the counter shaft is returned and transmitted to the standard speed and lodging speed gears provided on the main cutting shaft and output to the cutting device is known (Patent Document 1). Also conventionally, a first sub-transmission gear integrally formed with the second and third sub-transmission gears and constantly meshing with the output shaft is loosely fitted to the sub-transmission shaft so as to be axially slidable and non-rotatable relative to the first gear. A configuration in which any one of the meshing of the first counter gear, the second counter gear, and the third counter gear is selected and the counter shaft is sub-transmitted at any one of high speed, medium speed, and low speed is known (Patent Document 2).

[0003] Japanese Patent Application Laid-Open No. 2023-96964, Japanese Patent Application Laid-Open No. 2007-143558

[0004] Among the above-known examples, the former has a problem that transmission loss occurs because the rotation transmitted from the input shaft to the counter shaft is returned and transmitted to the standard speed and lodging speed gears provided on the main cutting shaft. Among the above-known examples, the latter has a configuration of only a transmission mechanism without speed change from the output shaft to the sub-transmission shaft. When the crop is lodged, it is necessary to lower (slow down) the traveling speed and perform the cutting operation, resulting in a problem of poor work efficiency. The present application provides a transmission that suppresses and transmits the transmission loss of the output to the cutting device.

[0005] The invention of claim 1 is a combine harvester in which a continuously variable transmission (20) that increases or decreases the output rotation of the engine (22) and switches the direction of rotation is provided downstream of the transmission path of the engine (22), and the output rotation of the continuously variable transmission (20) is transmitted to a running device (2) and a harvesting device (4) via a transmission (23), wherein the variable rotation of the continuously variable transmission (20) is provided with two transmission paths: a direct transmission path in which the rotation of the continuously variable transmission (20) is transmitted from the output shaft of the continuously variable transmission (20) via gears to a first shaft (29) and output to the harvesting device (4), and a detour transmission path in which the drive rotation transmitted indirectly via a second shaft (32) provided separately from the first shaft (29) is returned to the first shaft (29) and output to the harvesting device (4).

[0006] In the invention of claim 1, the variable speed rotation of the continuously variable transmission 20 is transmitted via two transmission paths: a direct transmission path from the output shaft of the continuously variable transmission 20 to the first shaft 29 via gears and output to the harvesting device 4; and a detour transmission path that transmits the drive rotation via a second shaft 32, which is provided separately from the first shaft 29, and returns it to the first shaft 29 for output to the harvesting device 4. With this configuration, the variable speed rotation from the continuously variable transmission 20 is transmitted to the first shaft 29 via the direct transmission path and output to the harvesting device 4, thereby reducing the number of meshing gears and rotating shafts and minimizing power transmission loss. Furthermore, by transmitting the variable speed rotation of the continuously variable transmission 20 to the first shaft 29 via a second shaft 32, which is provided separately from the first shaft 29, and then via a second gear 43 through a detour transmission path, two transmission mechanisms can be provided within the transmission case 21 to transmit the rotation of the continuously variable transmission 20 to the harvesting device 4.

[0007] Side view of the combine harvester. Perspective view of the transmission. Schematic front view of the transmission. Schematic front view of the transmission. Schematic diagram of the belt mechanism that outputs from the transmission to the harvesting device. Side and front views of the belt mechanism. Diagrams of other embodiments of the belt mechanism. Longitudinal front view of the transmission case before the installation of the continuously variable transmission. Longitudinal front view of the transmission case with the continuously variable transmission installed. Enlarged cross-sectional view of the clutch portion of the transmission case. Front view of the continuously variable transmission. Right side view of the continuously variable transmission. Top view of the continuously variable transmission. Bottom view of the continuously variable transmission.

[0008] One embodiment of the present invention will be explained with reference to the drawings. 1 is the machine frame, 2 is a traveling device located below the machine frame 1, 3 is a threshing device located above the machine frame 1, 4 is a harvesting device located in front of the machine frame 1, 5 is a grain tank located on the side of the threshing device 3 for temporarily storing the grain removed from the threshing device 3, and 6 is a control unit. The harvesting device 4 has a grass divider 8 at the front and a lifting device 9 arranged in parallel behind the grass divider 8. 12 is a feeder chain. The traveling device 2 is configured to change its travel speed using a hydraulic static transmission (HST) 20, and the rotation transmitted to the harvesting device 4 is also changed in sync with the travel speed of the traveling device 2. Specifically, rotation from the engine 22 is input to the hydraulic continuously variable transmission 20, and the rotation, which has been continuously variable by the hydraulic continuously variable transmission 20, is output to the travel device 2 and the harvesting device 4 via the transmission 23, driving the harvesting device 4 at a working speed synchronized with the travel speed. The transmission 23 is enclosed in the transmission case 21.

[0009] A hydraulic continuously variable transmission 20 is provided on the upper part of either the left or right side of the transmission case 21, and the output shaft 24 of the hydraulic continuously variable transmission 20 is connected to the input shaft 25 of the transmission 23. An output gear (an example of a gear) 27 is provided on the input shaft 25. A first shaft (harvesting output shaft) 29 that outputs to the harvesting device 4 is provided near the input shaft 25, and a first gear (driven gear) 30 rotatably mounted on the first shaft 29 is constantly meshed with the output gear 27. The end of the first shaft 29 protrudes outward from the transmission case 21, and a harvesting output pulley 31 is attached to it. A second gear 43 is separately provided on the first shaft 29. A second shaft (counter shaft) 32 is provided near the first shaft 29, and a third gear (counter gear) 46 is fixed to the second shaft 32, and the third gear 46 is constantly meshed with the first gear 30. A fourth gear 45 is provided on the second shaft 32, and the fourth gear 45 is always engaged with the second gear 43. A fifth gear 47 is provided in the middle position of the second shaft 32, and rotation is output to the third shaft 26 via the fifth gear 47. This is finally transmitted to the side clutch (not shown) to drive the wheel shaft 40, which in turn drives the running gear 2 and moves the machine. When one of the left or right side clutches is disengaged, a slow turn is possible, and when the brake is applied, a sharp turn is possible.

[0010] A continuously variable transmission (CVT) 20 is provided downstream of the transmission path of the engine 22 to increase / decrease the output speed of the engine 22 and switch the direction of rotation (forward / reverse rotation). The output speed of the CVT 20 is transmitted to the running gear 2 and the harvesting gear 4 via the transmission 23. The output speed of the engine 22 is transmitted from the output shaft 24 of the CVT 20 to the input shaft 25 of the transmission 23, and to the first shaft 29, second shaft 32 and third shaft 26 of the transmission 23. The first shaft 29 is connected to the input shaft 25 of the transmission 23. The first shaft 29 is provided with a first gear 30 that is always meshed with the first gear 27, a second gear 43, and a clutch (clutch sleeve) 48 that rotates integrally with the first shaft 29 between the first gear 30 and the second gear 43. The second shaft 32 is provided with a third gear 46 that is always meshed with the first gear 30, a fourth gear 45 that is always meshed with the second gear 43, and a fifth gear 47 that transmits rotation to the third shaft 26. The first gear 30 is provided with an engagement portion 50 that engages with the engagement portion 48A of the clutch 48, and the second gear 43 is provided with an engagement portion 51 that engages with the engagement portion 48B of the clutch 48.

[0011] In this case, the clutch 48 only needs to be configured to switch between transmitting the rotation of the first gear 30 or the second gear 43 to the first shaft 29, and the configuration is arbitrary. For example, in this embodiment, a clutch sleeve (clutch release bearing) equipped with a sleeve is used, and it is configured to slide axially on the first shaft 29. Therefore, while providing a transmission mechanism for speed changes to the harvesting device 4, there is little power transmission loss, it is lightweight and compact, and the number of harvesting speed changes can be increased by using a double pulley for the harvesting output. In this embodiment, the first gear 30 is rotatably mounted on the first shaft 29, and when engaged with the clutch 48, the rotation of the first gear 30 is transmitted to the first shaft 29. Similarly, the second gear 43 is rotatably mounted on the first shaft 29, and when engaged with the clutch 48, the rotation of the second gear 43 is transmitted to the first shaft 29.

[0012] The variable speed rotation of the continuously variable transmission 20 is provided by two transmission paths: a direct transmission path from the first shaft 29, which is rotated via gears from the output shaft 24 of the continuously variable transmission 20, to the harvesting device 4; and a detour transmission path that returns the drive rotation, which is transmitted via a second shaft 32 (provided separately from the first shaft 29), to the first shaft 29 and outputs it to the harvesting device 4 (Figure 4). Therefore, the variable speed rotation from the continuously variable transmission 20 can be transmitted directly to the first shaft 29 via a transmission path and output to the harvesting device 4, reducing the number of meshing gears and rotating shafts and minimizing power transmission loss. Additionally, by transmitting the variable speed rotation of the continuously variable transmission 20 to the first shaft 29 via a detour transmission path that goes through a second shaft 32, which is provided separately from the first shaft 29, and then to the first shaft 29 via a second gear 43, the rotation of the continuously variable transmission 20 can be transmitted to the harvesting device 4 via two transmission paths within the transmission case 21.

[0013] A gear 27 on the output shaft 24 of the continuously variable transmission 20 is constantly engaged with a first gear 30 on the first shaft 29 located near the output shaft 24. The rotation of the first gear 30 is transmitted to a harvesting output pulley 31 located on the first shaft 29 protruding from the transmission case 21, and output to the harvesting device 4, thus forming a direct transmission path. A second gear 43, which is rotatably mounted separately on the first shaft 29, is provided with a second gear 43 that rotates by transmission from a second shaft 32 located near the first shaft 29, forming a bypass transmission path. A clutch 48 is provided between the first gear 30 and the second gear 43 to selectively switch and transmit the rotation of either the first gear 30 or the second gear 43 to the first shaft 29, thereby switching between the direct transmission path and the bypass transmission path. Therefore, the variable speed rotation from the continuously variable transmission 20 can be directly transmitted to the first shaft 29 via a transmission path and output to the harvesting device 4, reducing the number of meshing gears and rotating shafts and minimizing transmission loss of output. In addition, rotation can be transmitted to the first shaft 29 via a bypass transmission path from the second shaft 32, which is provided separately from the first shaft 29, through a second gear 43, and output to the harvesting device 4. Thus, the rotation of the continuously variable transmission 20 can be varied and transmitted to the harvesting device 4 via two transmission paths.

[0014] In other words, in the conventional configuration, all rotation of the continuously variable transmission 20 is transmitted from the first shaft 29 through the second shaft 32 back to the first shaft 29 and then to the harvesting device 4. This increases the number of meshing gears and rotating shafts, resulting in transmission loss. The present invention solves this problem and suppresses transmission loss. A clutch 48 is provided on the first shaft 29 between the first gear 30 and the second gear 43. An engaging portion 50 that engages with and disengages from the engaging portion 48A of the clutch 48 is provided on the clutch 48 side of the first gear 30, and an engaging portion 51 that engages with and disengages from the engaging portion 48B of the clutch 48 is provided on the clutch 48 side of the second gear 43. Therefore, when the engagement portion 48A of the clutch 48 is connected to the first gear 30, rotation is transmitted from the output shaft 24 of the continuously variable transmission 20 → input shaft 25 of the transmission case 21 → gear 27 → first gear 30 → clutch 48 → first shaft 29 and output to the harvesting device 4. Also, when the clutch 48 is switched and connected to the second gear 43, the rotation transmitted from the output shaft 24 of the continuously variable transmission 20 → input shaft 25 of the transmission case 21 → gear 27 → first gear 30 → third gear 46 → second shaft 32 → fourth gear 45 → second gear 43 → clutch 48 → first shaft 29 is output to the harvesting device 4.

[0015] In other words, by configuring the first gear 30 on the first shaft 29 to serve as both a transmission gear that transmits the variable speed rotation of the continuously variable transmission 20 to another rotating shaft (second shaft 32) and an input gear that transmits rotation to the first shaft 29, a direct transmission path can be constructed, simplifying the transmission path and suppressing transmission loss. The first gear 30 and the second gear 43 are configured such that the rotation transmitted by the first gear 30 to the first shaft 29 is the standard speed, and the rotation transmitted by the second gear 43 to the first shaft 29 is the high-speed rotation (lodging rotation). Therefore, while being able to handle the harvesting of lodged grain stalks, the configuration of the transmission path for the standard speed harvesting operation, which is commonly used, is simplified, transmission loss is suppressed, and the durability of the transmission path is improved.

[0016] The harvesting output pulley 31 is composed of a pair of pulley bodies 53, and the pulley bodies 53A and 53B of the pair of harvesting output pulleys 31 have different diameters. As a result of the miniaturization of the transmission 23, it is possible to arrange a double pulley, which was not possible in the conventional design, and the number of gear shifting stages can be increased to four. Specifically, by switching the first gear 30 and the second gear 43 with the clutch 48, a two-stage gear shift is achieved, and by further configuring a two-stage gear shift using a double pulley, the number of gear shifting stages output to the harvesting device 4 can be configured to four.

[0017] This configuration allows for the selection and setting of a harvesting speed that matches the crop (matching the degree of lodging of the grain stalks) by increasing the number of speed settings. Increasing the harvesting speed also thins the layer of conveyed grain stalks, reducing the threshing load. The transmission path from the harvesting output pulley 31 to the harvesting device 4 is configured to switch between a pair of belts 54 and separate tension pulleys 55, and the switching of the tension pulleys 55 is performed by a lever 56 or a motor 57 (Figures 5 and 6). An engagement portion 50 is provided on the first gear 30, which is rotationally transmitted from a gear 27 provided on the input shaft 25 of the continuously variable transmission 20. Therefore, the variable speed rotation from the continuously variable transmission 20 can be transmitted to the engagement portion 48A of the clutch 48 via the engagement portion 50 of the first gear 30, and the first gear 30 and the clutch 48 can directly form a transmission path, reducing the number of meshing gears and rotating shafts, and thus reducing the output to the harvesting device 4, thereby reducing the transmission loss of the output.

[0018] This reduces the number of parts and assembly time in the transmission mechanism from the continuously variable transmission 20 to the harvesting device 4, lightens the transmission 23, reduces the environmental impact by reducing the number of parts, and improves durability by increasing the thickness of the first gear 30, which is used frequently. In addition, the reduction in the number of parts in the upper part of the transmission case 21 leads to a lower center of gravity of the transmission case 21, stabilizing the machine's posture and improving the machine's running stability. Furthermore, the first shaft 29 of the transmission case 21 of this invention has fewer gears on the shaft compared to conventional transmission structures, reducing the load on the shaft and allowing for a thinner shaft diameter. Also, because the first shaft 29 has fewer gears on the shaft compared to conventional transmission structures, the shaft length of the first shaft 29 can be shortened, which reduces the amount of shaft deflection and thus reduces noise and vibration. In addition, the weight of the machine can be reduced, improving fuel efficiency. Furthermore, the harvesting cylinder is positioned in the center of the machine frame 1 in the left-right direction. Therefore, by positioning the support position of the harvesting device 4 at the center of the machine, the stability of the machine is improved.

[0019] The harvesting output pulley 31 is configured as a so-called double pulley. In this case, the harvesting output pulleys 31 of the double pulley have different diameters. As a result, with the miniaturization of the transmission 23, it becomes possible to arrange the double pulley, which could not be arranged in the conventional way, and the number of gear stages increases to four. That is, by switching the first gear 30 and the second gear 43 with the clutch 48, a two-speed transmission is achieved, and further, by configuring a two-speed transmission with the double pulley, the number of gear stages can be configured to four. This configuration, with an increased number of gear stages, allows for the selection and setting of the harvesting speed according to the crop, and increasing the harvesting speed thins the layer of conveyed grain stalks, thereby reducing the threshing load. The transmission is switched by separate tension pulleys 55 on each of the pair of belts 54 in the transmission path from the harvesting output pulley 31 to the harvesting device 4. As a result, increasing the harvesting speed thins the layer of straw, reducing the threshing load. The tension pulley 55 is switched using a lever 56.

[0020] The mounting configuration of the tension pulley 55 is arbitrary, but as an example, a pair of tension pulleys 55 are provided on the left and right, each in contact with the belt 54, and the tension pulleys 55 are attached to the tips of the arms 58, the base of the arms 58 is rotatably attached to a fixed part, and levers 56 are attached to the base of the arms 58 so that the arms 58 can rotate integrally with them (Figure 6). Therefore, when either of the left or right levers 56 is operated, it contacts the belt 54, turns on the power transmission, and outputs to the harvesting device 4. The levers 56 may also be made longer in the vertical direction and configured to be directly operated from the control unit 6. The switching of the tension pulleys 55 may be configured using a motor 57. In this case, the motor 57 can be provided instead of the levers 56 in Figure 6. The switching is done with a single motor 57. Therefore, the switching mechanism can be made simple.

[0021] In this case, the configuration of the tension switching mechanism is arbitrary, but a rotating body 60 is fixed to the output shaft of the motor 57, and the rotating body 60 and a pair of levers 56 are connected via arms 61 and rods 62 (Figures 2 and 7). Therefore, when the motor 57 is energized and the rotating body 60 is rotated once, one arm 61 turns on the tension pulley 55, and the other arm 61 turns off the tension pulley 55. Note that the output to the harvesting device 4 can be stopped separately from the tension switching mechanism by stopping the output of the continuously variable transmission 20 or by a harvesting clutch (not shown), etc. An engagement portion 51 is provided on the second gear 43, which is rotationally transmitted from the gear 27 of the continuously variable transmission 20 via a bypass transmission path, and the first shaft 29 is rotated by the clutch 48 via the engagement portion 51. In addition, the number of teeth of the second gear 43 is made less than the number of teeth of the first gear 30 so that the first shaft 29 rotates at high speed.

[0022] In other words, when the engagement portion 48B of the clutch 48 is engaged with the engagement portion 51 of the second gear 43, the rotation of the second gear 43 is transmitted to the first shaft 29 via the clutch 48, and the harvesting device 4 is driven at high speed as the lodging speed via the belt transmission from the harvesting output pulley 31. The second gear 43, which is rotationally transmitted from the gear 27 of the continuously variable transmission 20, is provided with an engagement portion 51, and the rotation is transmitted to the clutch 48 via the engagement portion 51 to rotate the first shaft 29. The first shaft 29 is configured to rotate at a standard speed, and in addition, the rotational transmission to the first shaft 29 is cut off by moving the clutch 48.

[0023] In other words, when the clutch 48 is moved to the left in the figure, the engagement portion 48B of the clutch 48 that is engaged with the engagement portion 51 of the second gear 43 disengages from the engagement portion 51 of the second gear 43, and the drive rotation transmitted from the gear 27 to the first shaft 29 is interrupted as the clutch 48 enters a neutral state. The rotation from the gear 27 of the continuously variable transmission 20 is transmitted at high speed through a bypass transmission path: first gear 30 → third gear 46 → second shaft 32 → fourth gear 45 → second gear 43. The engagement portion 48B of the clutch 48 is moved to the right in the figure, engaging with the engagement portion 51 of the second gear 43, causing the first shaft 29 to rotate at high speed (lodging speed) and the harvesting device 4 to rotate at high speed. In other words, when the clutch 48 is moved to the right in Figure 3 and the engaging portion 48B of the clutch 48 is engaged with the engaging portion 51 of the second gear 43, the rotation of the second gear 43 is transmitted to the first shaft 29 via the clutch 48, and the harvesting device 4 is driven at high speed via the belt drive from the harvesting output pulley 31.

[0024] Furthermore, the tooth width (gear width) of the first gear 30 is configured to be greater than or equal to the tooth width of the second gear 43. This improves the durability of the first gear 30, which is used frequently. The left wall 69 of the transmission case 21 and the second gear 43 are configured to be relatively close together, and it is preferable to shorten the first shaft 29 that provides the harvesting output to the vicinity of the second gear 43. This makes the transmission case 21 smaller. As a result, the length of the first shaft 29 is shortened, so the deflection of the first shaft 29 itself can be reduced, and noise and vibration are reduced. Figure 8 is a longitudinal front view of another embodiment of the continuously variable transmission 20 before it is mounted on the transmission case 21, and Figure 10 is an enlarged cross-sectional view of the clutch 48 portion of this transmission case 21.

[0025] However, the transmission case 21 is configured to receive the rotation of the engine 22 from the top and transmit it to the travel device 2 from the lower wheel shaft 40 to drive the harvesting device 4 in synchronization with the travel speed. For this reason, it is well known that the continuously variable transmission 20 is mounted on one side of the transmission case 21, either left or right. However, in conventional examples, the continuously variable transmission 20 was simply mounted on the side of the transmission case 21, which resulted in the problem that the mounting metal part of the continuously variable transmission 20 was contaminated by dust and mud splashes from the harvesting device 4 while it was in motion. Therefore, in the present invention, a notch 70 is provided on one side of the upper part of the transmission case 21, either left or right, with at least the lower side closed when viewed from the front, and the mounting metal part (pressure sensing port) 71 of the continuously variable transmission 20 is arranged within the notch 70 (Figure 8).

[0026] Therefore, the mounting metal portion 71 of the continuously variable transmission 20 is protected by the shaft housing portion 73 which forms the notch 70, preventing contamination by dust from the harvesting device 4 during operation and mud splashes from the running device 2. The notch 70 is formed above the shaft housing portion 73 which houses the second shaft 32 adjacent to the gear 27 that outputs rotation from the output shaft 24 of the continuously variable transmission 20. Therefore, the notch 70 can be constructed using the components of the transmission case 21, resulting in a rational configuration. The mounting metal portion 71 of the continuously variable transmission 20 is configured to overlap with the transmission case 21 when viewed in a direction perpendicular to the input shaft 25 (output shaft 24) of the continuously variable transmission 20.

[0027] In other words, in a side view, the vertical imaginary line L passing through the input shaft 25 of the continuously variable transmission 20 is positioned to overlap with the mounting metal portion 71 (Figure 9). Therefore, the mounting metal portion 71 of the continuously variable transmission 20 is protected by the shaft housing portion 73 to prevent contamination by dust from the harvesting device 4 during operation and mud splashes from the running device 2. In this case, in a side view, it is preferable to make the front-to-back width of the shaft housing portion 73 greater than the front-to-back width of the mounting metal portion 71 of the continuously variable transmission 20 to improve the protective function. The continuously variable transmission 20 has oil passages (not shown) arranged vertically in the left-to-right direction with respect to the direction of machine travel, and each of the upper and lower oil passages is provided with a vertical pressure sensing port for mounting a pressure gauge for pressure sensing. The pressure sensing port is closed by a screw cap 76 when not measuring pressure, and a space S for attaching and detaching the screw cap 76 is provided between the lower screw cap 76 and the shaft housing portion 73 (Figure 9).

[0028] Therefore, a pressure sensing port communicating with the oil passages inside the continuously variable transmission 20 can be provided on the mounting metal portion 71 of the continuously variable transmission 20. The lower screw cap 76 that closes the pressure sensing port is protected by the shaft housing portion 73, which prevents the adhesion of mud and straw debris. As a result, pressure sensing maintenance can be performed simply by removing the screw cap 76 and attaching a pressure gauge to the pressure sensing port, making maintenance work easy. The configuration of the continuously variable transmission 20 is arbitrary, but at a minimum, oil passages in the left-right direction relative to the direction of machine travel should be arranged vertically, and vertical pressure sensing ports for attaching pressure gauges should be provided to communicate with each of the upper and lower oil passages. Since the continuously variable transmission 20 is configured to transmit power from its output shaft 24 to the first shaft 29 of the transmission case 21 via the input shaft 25 of the transmission 23, and then output from the first shaft 29 to the harvesting output pulley 31, the width of the transmission case 21 in the portion where the continuously variable transmission 20 is installed can be reduced, thereby allowing a notch 70 to be formed on either the left or right side of the upper part of the transmission case 21, with at least the lower side closed when viewed from the front.

[0029] As a result, the mounting metal portion 71 of the continuously variable transmission 20 can be positioned within the notch 70, and the mounting metal portion 71 of the continuously variable transmission 20 is protected by the shaft housing portion 73 that constitutes the notch 70, preventing contamination by dust from the harvesting device 4 during operation and mud splashes from the running device 2. In addition, the first shaft 29 has a structure with fewer gears on the shaft compared to conventional transmission structures, so the shaft length of the first shaft 29 can be shortened, which reduces the amount of shaft deflection, thus reducing noise and vibration. Furthermore, the outer end surface 73A of the shaft housing portion 73 is offset to the right by protruding from the end surface 70A of the notch 70 of the transmission case 21, protecting the lower side of the mounting metal portion 71.

[0030] Furthermore, the shape of the notch 70 in the transmission case 21 can be adjusted so that the continuously variable transmission 20 is positioned closer to the center of the front center line of the transmission case 21. This reduces the amount of protrusion of the continuously variable transmission 20 from the end face 70A of the notch 70 in the transmission case 21, thus increasing the freedom of layout for peripheral devices other than the transmission case 21. For similar reasons, the continuously variable transmission 20 is positioned closer to the center line of the transmission case 21, allowing the input shaft of the continuously variable transmission 20 from the engine 22 to be shortened, reducing the amount of protrusion (offset) of the continuously variable transmission 20 from the transmission case 21, and increasing the freedom of layout. In this embodiment, the left side in the direction of machine travel is made smaller, and the continuously variable transmission 20 is provided in the notch 70 formed on the left side of the transmission case 21. The continuously variable transmission 20 and the harvesting output pulley 31 are arranged in a straight line, allowing the first shaft 29 to be shorter and smaller in diameter.

[0031] The continuously variable transmission 20 is positioned near the transmission case 21. In this transmission case 21, at least the input shaft 22A from the engine 22 is made thinner. As a result, the input shaft 22A has fewer gears on the shaft compared to conventional transmission structures, allowing for a shorter shaft length. Consequently, the amount of shaft deflection is reduced, resulting in less noise and vibration.

[0032] 1...Machine frame, 2...Traction mechanism, 3...Threshing mechanism, 4...Harvesting mechanism, 5...Grain tank, 6...Control unit, 20...Hydraulic continuously variable transmission, 21...Transmission case, 22...Engine, 22A...Input shaft, 23...Transmission, 24...Output shaft, 25...Input shaft, 26...Third shaft, 27...Output gear, 29...First shaft (harvesting output shaft), 30...First gear (driven gear), 31...Harvesting output pulley, 32...Second shaft (counter shaft), 43...Second gear, 45...Fourth gear, 46...Third gear (counter gear), 47...Fifth gear, 48...Clutch, 48A...Engaging part, 48B...Engaging part, 50...Engaging part, 51...Engaging part, 71...Mounting metal part

Claims

1. A combine harvester in which a continuously variable transmission (20) that increases or decreases the output rotation of the engine (22) and switches the direction of rotation is provided downstream of the transmission path of the engine (22), and the output rotation of the continuously variable transmission (20) is transmitted to a running gear (2) and a harvesting device (4) via a transmission (23), wherein the continuously variable rotation of the continuously variable transmission (20) is provided with two transmission paths: a direct transmission path in which the rotation is transmitted from the output shaft of the continuously variable transmission (20) via gears to a first shaft (29) and output to the harvesting device (4), and a detour transmission path in which the drive rotation transmitted indirectly via a second shaft (32) provided separately from the first shaft (29) is returned to the first shaft (29) and output to the harvesting device (4).

2. In claim 1, the output rotation of the engine (22) is transmitted from the output shaft (24) of the continuously variable transmission (20) to the input shaft (25) of the transmission (23) to the first shaft (29), the second shaft (32), and the third shaft (26) of the transmission (23), wherein the first shaft (29) has a first gear (30) that is always meshed with the gear (27) of the input shaft (25) of the transmission (23), a second gear (43), and the first shaft (29) between the first gear (30) and the second gear (43). A combine harvester is provided with a clutch (48) that rotates integrally with the gear, and the second shaft (32) is provided with a third gear (46) that is always meshed with the first gear (30), a fourth gear (45) that is always meshed with the second gear (43), and a fifth gear (47) that transmits rotation to the third shaft (26), the first gear (30) is provided with an engagement portion (50) that engages with the engagement portion (48A) of the clutch (48), and the second gear (43) is provided with an engagement portion (51) that engages with the engagement portion (48B) of the clutch (48).

3. In claim 2, the gear (27) provided on the output shaft (24) of the continuously variable transmission (20) is constantly meshed with the first gear (30) on the first shaft (29) provided near the output shaft (24), and the rotation of the first gear (30) is transmitted to the harvesting output pulley (31) provided on the first shaft (29) protruding from the transmission case (21), thereby providing a direct transmission path configuration to the harvesting device (4), and the first shaft (2 9) A combine harvester is provided with a second gear (43) which is rotated by transmission from the second shaft (32) located near the first shaft (29) to form a bypass transmission path, and a clutch (48) is provided between the first gear (30) and the second gear (43) to selectively switch and transmit the rotation of either the first gear (30) or the second gear (43) to the first shaft (29), thereby switching between a direct transmission path and a bypass transmission path.

4. The combine harvester according to claim 3, wherein the clutch (48) is provided on the first shaft (29) between the first gear (30) and the second gear (43), the clutch (48) side of the first gear (30) is provided with the engaging portion (50) that engages with and disengages from the engaging portion (48A) of the clutch (48), and the clutch (48) side of the second gear (43) is provided with the engaging portion (51) that engages with and disengages from the engaging portion (48B) of the clutch (48).

5. A combine harvester according to claim 1 or 2, characterized in that a notch (70) is provided on either the left or right upper side of the transmission case (21), with at least the lower side closed when viewed from the front, and the mounting metal portion (71) of the continuously variable transmission (20) is arranged within the notch (70).

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