Tractor travel transmission

Abstract

The creeping speed change device is accommodated in the driving transmission device of the tractor of the gearbox, which can suppress the enlargement of the gearbox and can make the overall reduction ratio of the creeping speed change higher. The creeping speed change device (60) comprises a first transmission gear (66), a first reduction gear (62), a second transmission gear (67), a second reduction gear (63), a third transmission gear (68), a third reduction gear (64), and a reduction gear pair (65), wherein the first transmission gear (66) is arranged on the output shaft gear (54b) of the gear transmission (40), the first reduction gear (62) is supported on the intermediate shaft (61) so as to be relatively rotatable while being meshed with the first transmission gear (66), and the second transmission gear (67) is arranged on the first reduction gear ( 62), the second reduction gear (63) is supported on the output shaft (43) of the gear transmission (40) so as to be relatively rotatable when meshed with the second transmission gear (67), the third transmission gear (68) is arranged on the second reduction gear (63), the third reduction gear (64) is supported on the intermediate shaft (61) so as to be non-rotatable when meshed with the third transmission gear (68), and the reduction gear pair (65) is arranged throughout the intermediate shaft (61) and the output shaft (43) to reduce the power of the intermediate shaft (61) and transmit it to the output shaft (43).

Description

Technical Field

[0001] The present invention relates to a traveling transmission device for a tractor and a tractor equipped with the traveling transmission device for a tractor.

[0002] The present invention also relates to a tractor having a transmission and an axle box, wherein the transmission has a built-in differential mechanism for transmitting power to an axle, and the axle box is connected to a lateral side of the transmission by means of connecting bolts to rotatably support the axle. Background Art [Background technology 1]

[0004] As a driving transmission device for a tractor, there is a driving transmission device including a gear transmission, a creeper transmission device, and a transmission case. The gear transmission receives power from the engine and outputs the input power after speed change. The creeper transmission receives output from the gear transmission and outputs the input power to a differential mechanism for rear wheels after speed reduction. The transmission case accommodates the gear transmission and the creeper transmission device.

[0005] As a creep transmission device of the traveling transmission device of such a tractor, there is a creep transmission device shown in Patent Document 1, for example. The creep transmission device shown in Patent Document 1 includes a creep input gear provided integrally with the low-speed third gear of the auxiliary transmission device, a reduction gear meshing with the creep input gear, a creep output gear provided in parallel with the reduction gear, and a creep gear meshing with the creep output gear. That is, the power of the low-speed third gear is decelerated between the creep input gear and the reduction gear, and the decelerated power is decelerated between the creep output gear and the creep gear, and is input from the transmission shaft to the rear wheel differential device. [Background technology 2]

[0007] Among the above-mentioned tractors, for example, as shown in Patent Document 2, there is a tractor equipped with a brake device having a brake disc, a disc receiving portion, and a rotating cam for pressing the brake disc toward the disc receiving portion to brake the axle.

[0008] Patent document 1: Japanese Patent Application Laid-Open No. 10-6792.

[0009] Patent document 2: Japanese Patent Application Laid-Open No. 10-6789. Summary of the invention

[0010] [Question 1]

[0011] The problems with respect to [Background Art 1] are as follows.

[0012] Conventionally, the creep shift is performed with respect to two gear pairs, so in order to increase the overall reduction ratio of the creep shift, it is necessary to use gears with a large gear diameter, which increases the size of the transmission.

[0013] The present invention provides a driving transmission device for a tractor and a tractor capable of suppressing an increase in the size of a transmission and increasing the speed reduction ratio of the entire creep shift.

[0014] [Question 2]

[0015] The problems with respect to [Background Art 2] are as follows.

[0016] In the past, the brake device was installed inside the axle box, and the braking reaction force when the brake was applied was applied to the support shaft box. Therefore, especially in large tractors that require strong braking force, the axle box had to have the strength to resist the strong braking reaction force, and the cost of the axle box became high. In addition, the axle box became heavy.

[0017] The present invention provides a tractor which can avoid the increase in cost and weight of an axle box and has forced power.

[0018] The solution corresponding to [Question 1] is as follows.

[0019] The travel transmission device of the tractor of the present invention comprises a gear transmission, a creeper transmission device, and a gearbox, wherein the power of the engine is input to the gear transmission, and the input power is output after the speed is changed, and the output of the gear transmission is input to the creeper transmission device, and the input power is output to a differential mechanism for rear wheels after the speed is reduced, and the gearbox accommodates the gear transmission and the creeper transmission device, and the gear transmission comprises an output shaft and an output shaft gear, and the output shaft transmits power to the differential mechanism, and the output shaft gear is supported on the output shaft and can be switched to a transmission connection state in which the output shaft is non-rotatably engaged with the output shaft and the power is transmitted to the output shaft, and a transmission disconnection state in which the engagement with the output shaft is released and the power transmission to the output shaft is cut off, and the creeper transmission device comprises an intermediate shaft, a first transmission gear, a first reduction gear, a second transmission gear, a second reduction gear, a third transmission gear, a third reduction gear, and a reduction gear pair, and the intermediate shaft is parallel to the output shaft, and the output shaft gear is supported on the output shaft and can be switched to a transmission connection state in which the output shaft is non-rotatably engaged with the output shaft and the power is transmitted to the output shaft, and ... output shaft gear is supported on the output shaft and can be switched to a transmission connection state in which the output shaft is non-rotatably engaged with the output shaft and the power is transmitted to the output shaft, and the engagement with the output shaft is released and the power transmission to the output shaft is cut off, and the creeper transmission device comprises an intermediate shaft The first transmission gear is non-rotatably arranged on the aforementioned output shaft gear, the aforementioned first reduction gear is supported on the aforementioned intermediate shaft for relative rotation while being meshed with the aforementioned first transmission gear, and rotates at a speed lower than the aforementioned first transmission gear, the aforementioned second transmission gear is non-rotatably arranged on the aforementioned first reduction gear, the aforementioned second reduction gear is supported on the aforementioned output shaft for relative rotation while being meshed with the aforementioned second transmission gear, and rotates at a speed lower than the aforementioned second transmission gear, the aforementioned third transmission gear is non-rotatably arranged on the aforementioned second reduction gear, the aforementioned third reduction gear is supported on the aforementioned intermediate shaft for relative rotation while being meshed with the aforementioned third transmission gear, and rotates at a speed lower than the aforementioned third transmission gear, the aforementioned reduction gear pair is arranged throughout the aforementioned intermediate shaft and the aforementioned output shaft, and can be switched between a transmission-on state in which the power of the aforementioned intermediate shaft is decelerated and transmitted to the aforementioned output shaft, and a transmission-off state in which the power transmission relative to the aforementioned output shaft is cut off.

[0020] According to this structure, the power of the output shaft gear is subjected to a crawl shift as a whole by the gear pair of the first transmission gear and the first reduction gear, the gear pair of the second transmission gear and the second reduction gear, the gear pair of the third transmission gear and the third reduction gear, and the reduction gear pair, that is, the crawl shift is performed by using more gear pairs than before, so even if each gear pair uses a gear with a smaller gear diameter than before, the crawl shift is performed with the same reduction ratio as before, or a higher reduction ratio than before. The output shaft is effectively used as a support shaft of the second reduction gear, so there is no need to provide a special support shaft for the second reduction gear.

[0021] Therefore, it is possible to suppress an increase in the size of the transmission and to increase the speed reduction ratio of the entire creep shift so that the vehicle can travel at an extremely low speed.

[0022] In the present invention, preferably, in a direction along the axis of the intermediate shaft, the reduction gear pair is located on a side opposite to a side where the first reduction gear is located with respect to the output shaft gear.

[0023] According to this structure, the reduction gear pair and the first reduction gear can be dispersedly arranged in the space inside the transmission on the side where one end side of the rotating shaft of the output shaft gear is located and the space inside the transmission on the side where the other end side of the rotating shaft of the output shaft gear is located, so it is easy to effectively utilize the vacant space in the transmission as the installation space of the creeping speed device, which can suppress the enlargement of the transmission.

[0024] In the present invention, it is preferred that the aforementioned intermediate shaft is arranged below the aforementioned output shaft, and the clutch for switching the aforementioned reduction gear pair into the aforementioned transmission connection state and the aforementioned transmission disconnection state is arranged throughout the aforementioned reduction gear pair, the transmission gear supported on the aforementioned intermediate shaft, and the aforementioned intermediate shaft.

[0025] According to this configuration, the clutch can be arranged at the bottom side portion of the transmission in the transmission interior space, so that the operation structure for operating the clutch from the outside of the transmission can be easily made compact.

[0026] In the present invention, it is preferred that a forward-reverse switching device, a rotating transmission shaft, and a high-low speed switching device are provided, the forward-reverse switching device having a clutch portion, the clutch portion being input with power from the engine and converting the input power into forward power and reverse power, and the forward-reverse switching device having a forward output portion for outputting the converted forward power and a reverse output portion for outputting the converted reverse power, respectively, the rotating transmission shaft being arranged throughout the reverse output portion and the input portion of the gear transmission to transmit the power of the reverse output portion to the input portion, and the high-low speed switching device being arranged throughout the forward output portion and the rotating transmission shaft to be switched into a high-speed transmission state in which the power of the forward output portion is shifted to the high-speed side to be transmitted to the rotating transmission shaft and a low-speed transmission state in which the power of the forward output portion is shifted to the low-speed side to be transmitted to the rotating transmission shaft.

[0027] According to this structure, the reverse power output by the forward-reverse switching device is input to the gear transmission without being affected by the speed shifting action of the high-low speed switching device, and the forward power output by the forward-reverse switching device is input to the gear transmission in a state of being shifted to the high-speed side and the low-speed side by the high-low speed switching device, so the speed during forward travel can be changed, and the transmission structure that can switch between forward travel and reverse travel only by switching the forward-reverse switching device can be simplified.

[0028] In the present invention, it is preferable that the rotation transmission shaft and the input portion are provided concentrically and in a straight line.

[0029] According to this configuration, the rotation transmission shaft and the input portion are disposed in a positional relationship that facilitates connection, so that the rotation transmission shaft and the input portion can be linked and connected by a connection means having a simple structure.

[0030] In the present invention, it is preferable that the reverse output portion is disposed on the front side of the clutch portion, and the forward output portion is disposed on the rear side of the clutch portion.

[0031] According to this configuration, since the reverse output unit and the forward output unit do not overlap, the forward / reverse switching device can be simplified in structure.

[0032] In addition, the travel transmission device of the tractor of the present invention includes a forward-reverse switching device, a gear transmission, a rotating transmission shaft, and a high-low speed switching device. The forward-reverse switching device is input with power from the engine, converts the input power into forward power and reverse power, and has a forward output part for outputting the converted forward power and a reverse output part for outputting the converted reverse power, respectively. The gear transmission has an input part to which power is input, and the power input to the input part is changed in speed to be output to the travel device. The rotating transmission shaft is arranged throughout the reverse output part and the input part, and transmits the power of the reverse output part to the input part. The high-low speed switching device is arranged throughout the forward output part and the rotating transmission shaft, and changes the speed of the power output of the forward output part to the high-speed side and the low-speed side, and outputs the power on the changed high-speed side and the power on the changed low-speed side to the rotating transmission shaft.

[0033] According to this structure, the reverse power output by the forward-reverse switching device is input to the gear transmission without being affected by the speed changing action of the high-low speed switching device, and the forward power output by the forward-reverse switching device is input to the gear transmission in a state of being shifted to the high-speed side and the low-speed side by the high-low speed switching device, so the speed during forward travel can be changed, and the transmission structure that can switch between forward travel and reverse travel only by switching the forward-reverse switching device can be simplified.

[0034] The traveling transmission device for a tractor of the present invention can be applied to a tractor.

[0035] According to the tractor provided with the travel transmission device of the tractor of the present invention, it is possible to obtain a tractor which can travel at an extremely low speed and can be easily operated while suppressing an increase in the size of the tractor.

[0036] The solution corresponding to [Question 2] is as follows.

[0037] The tractor of the present invention is equipped with a gearbox, an axle box, and a braking device. The gearbox has a built-in differential mechanism for transmitting power to the axle. The axle box is connected to the lateral side of the gearbox by means of connecting bolts to support the axle in a rotatable manner. The braking device has a brake disc, a disc receiving portion, and a rotating cam for pushing the brake disc toward the disc receiving portion to brake the axle. The brake disc, the disc receiving portion, and the rotating cam are equipped inside the gearbox.

[0038] According to this structure, the braking reaction force when the brake is applied acts on the transmission, but the transmission with functions such as a built-in differential mechanism has strong strength, so it is possible to have a braking device that can suppress the braking reaction force applied to the axle box and can exert a strong braking force.

[0039] Therefore, it is possible to provide a strong braking force while avoiding an increase in the cost and weight of the axle box, which would otherwise result in an increase in the strength of the axle box.

[0040] In the present invention, it is preferred that a cam operating arm, a brake operating member, and a rotating support shaft are provided, the cam operating arm is swingably arranged inside the above-mentioned transmission case, and the above-mentioned rotating cam is rotationally operated, the above-mentioned brake operating member is swingably arranged outside the above-mentioned transmission case, and the above-mentioned cam operating arm is swingably operated, the above-mentioned rotating support shaft is rotatably mounted on the through hole of the side wall portion of the above-mentioned transmission case, and is connected to the above-mentioned cam operating arm and the above-mentioned brake operating member, so that the above-mentioned cam operating arm and the above-mentioned brake operating member are swingably supported on the above-mentioned side wall portion, and the above-mentioned cam operating arm and the above-mentioned brake operating member are linked and connected.

[0041] According to this structure, when the brake operating member is operated, the rotating support shaft rotates, and the cam operating arm is swung by the rotating support shaft to rotate the rotating cam, and the rotating cam pushes the brake disc toward the disc receiving part. Therefore, the brake device can be simply operated by connecting a component such as a linkage rod connected to the brake pedal to the brake operating member outside the gearbox.

[0042] In the present invention, it is preferred that a boss component is provided, the boss component is relatively rotatably embedded in the rotating support shaft and is fixed to the side wall portion in a state of passing through the through hole, supporting the rotating support shaft, and the cam operating arm side portion of the boss component protrudes from the side wall portion to the inner side of the gearbox and abuts against the base end side portion of the cam operating arm.

[0043] According to this structure, the positional relationship between the cam operating arm and the side wall portion is set by means of the boss part to a positional relationship that produces a gap between the cam operating arm and the side wall portion. Therefore, even if the inner surface of the side wall portion is a casting surface, the cam operating arm is not adversely affected by the casting surface and can swing smoothly. Therefore, even if the inner surface of the side wall portion is not processed into a smooth surface, or even if it cannot be processed, the cam operating arm can swing smoothly to operate the braking device smoothly.

[0044] In the present invention, it is preferable that the brake operating element side portion of the boss member protrudes from the side wall portion toward the outside of the transmission case and abuts against a base end side portion of the brake operating element.

[0045] According to the present structure, the positional relationship between the brake operating member and the side wall portion is set by the boss component to a positional relationship that can produce a gap between the brake operating member and the side wall portion, so that components such as the linkage rod connected to the brake operating member do not contact the side wall portion and can be easily connected, so that the brake operating member can be smoothly swung without resistance from the side wall portion, and the brake operating system can be efficiently assembled to the brake operating member.

[0046] In the present invention, it is preferable to include a working port and a cover body, wherein the working port is open to a portion of the upper wall portion of the transmission corresponding to the upper side of the cam operating arm, and the cover body opens and closes the working port.

[0047] According to this structure, since the hand or the tool is put into the transmission case through the working opening from the outside of the transmission case to perform the work on the cam operating arm etc., the assembly of the cam operating arm etc. can be easily performed.

[0048] The tractor of the present invention comprises a body frame, a braking device, a cam operating arm, a brake operating member, a rotating support shaft, and a boss component. The body frame comprises a gearbox and an axle box. The gearbox has a built-in differential mechanism for transmitting power to the axle. The axle box is connected to the lateral side of the gearbox by means of connecting bolts to support the axle rotatably. The braking device is arranged inside the body frame to brake the axle. The cam operating arm is swingably arranged inside the gearbox to turn the braking device on and off. The brake operating member is swingably arranged outside the gearbox to swing the cam operating arm. The rotating support shaft is rotatably mounted on the gearbox. The through hole of the side wall portion is connected to the cam operating arm and the brake operating member, so that the cam operating arm and the brake operating member can support the side wall portion in a swinging manner, and the cam operating arm and the brake operating member are linked and connected, the boss member can be relatively rotatably embedded in the rotating support shaft, and is fixed to the side wall portion in a state of passing through the through hole, supporting the rotating support shaft, the cam operating arm side portion of the boss member protrudes from the side wall portion to the inner side of the gearbox and abuts against the base end side portion of the cam operating arm, and the brake operating member side portion of the boss member protrudes from the side wall portion to the outer side of the gearbox and abuts against the base end side portion of the brake operating member.

[0049] According to this structure, when the brake operating member is operated, the rotating support shaft rotates, the cam operating arm is swung by the rotating support shaft to rotate the rotating cam, and the rotating cam pushes the brake disc toward the disc receiving part. Therefore, the brake device can be simply operated by only connecting components such as a linkage rod connected to the brake pedal to the brake operating member outside the gearbox.

[0050] The positional relationship between the cam operating arm and the side wall is set by the boss component to a positional relationship that can generate a gap between the cam operating arm and the side wall, so that even if the inner side surface of the side wall is in a state of the casting surface, the cam operating arm will swing smoothly without being adversely affected by the casting surface. The positional relationship between the brake operating member and the side wall is set by the boss component to a positional relationship that can generate a gap between the brake operating member and the side wall, so that the components such as the linkage rod connected to the brake operating member do not contact the side wall and can be easily connected.

[0051] Therefore, even if the inner side surface of the side wall portion is in the state of a casting surface, it is possible to obtain a tractor in which the braking device can be smoothly operated and the assembly work of the operating system can be efficiently performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a diagram showing the first embodiment, and is a left side view showing the entire tractor.

[0053] Figure 2 1 is a diagram showing the first embodiment, and is a cross-sectional view showing the travel transmission device in a developed state.

[0054] Figure 3 1 is a diagram showing the first embodiment, and is a longitudinal sectional side view showing the forward / reverse switching device and the high / low speed switching device.

[0055] Figure 4 It is a figure which shows the 1st embodiment, and is a longitudinal sectional side view which shows the gear transmission and the creeper transmission device.

[0056] Figure 5 This is a diagram showing the first embodiment, and is a rear view showing the arrangement of an input shaft, a transmission intermediate shaft, an output shaft, an intermediate shaft, and a front wheel propeller shaft.

[0057] Figure 6 1 is a diagram showing the first embodiment, and is a cross-sectional view showing a travel transmission device having another implementation structure in a developed state.

[0058] Figure 7 This is a diagram showing a second embodiment, and is a left side view showing the entire tractor.

[0059] Figure 8 It is a figure which shows the 2nd embodiment, and is a longitudinal sectional side view which shows the driving|running|working device.

[0060] Fig. 9 It is a figure which shows the 2nd embodiment, and is a longitudinal sectional front view which shows a brake device.

[0061] Fig.10 It is a figure which shows the 2nd embodiment, and is a perspective view of the rear side split transmission case, the boss member, and the rotating support shaft. DETAILED DESCRIPTION

[0062] [First embodiment]

[0063] Hereinafter, an embodiment (first embodiment) as an example of the present invention will be described based on the drawings.

[0064] In the following description, the body of the tractor will be Figure 1 The direction of the arrow F shown is set to the "front of the vehicle body", the direction of the arrow B is set to the "rear of the vehicle body", the direction of the arrow U is set to the "above the vehicle body", the direction of the arrow D is set to the "below the vehicle body", the direction of the front side of the paper is set to the "left side of the vehicle body", and the direction of the back side of the paper is set to the "right side of the vehicle body".

[0065] like Figure 1As shown, the tractor has a vehicle body, and the vehicle body is equipped with a pair of left and right front wheels 1 as a travel device in a drivable and swingable manner, and a pair of left and right rear wheels 2 as a travel device in a drivable manner. A power unit 4 having an engine 3 is formed at the front of the vehicle body. A driving unit 7 is formed at the rear of the vehicle body, and the driving unit 7 has a driver's seat 5 and a steering wheel 6 for steering the front wheels 1. A linkage mechanism 9 that can connect various working devices to be raised and lowered is equipped at the rear of the vehicle body frame 8. The vehicle body frame 8 is composed of the engine 3, a clutch housing 10 connected to the rear of the engine 3, a transmission 11 connected to the clutch housing 10 at the front, and a front wheel support frame 12 extending forward from the engine 3.

[0066] In the tractor, a plow (not shown) and a rotary tilling device (not shown) are connected to the rear of the vehicle body via a linkage mechanism 9 to form a riding type tilling machine. A front loading device (not shown) is connected to the front of the vehicle body to form a loading working machine. In this way, various working machines are connected to the vehicle body to form various working machines. At the rear of the transmission 11, a power output shaft 13 is provided to output the power of the engine 3 to the connected working device.

[0067] [Regarding the Structure of the Traveling Transmission Device of the First Embodiment]

[0068] The driving transmission device 14 that transmits the power of the engine 3 to the front wheel 1 and the rear wheel 2 is as shown in FIG. Figure 2 The traveling transmission device 14 includes a transmission case 11. In the traveling transmission device 14, the front-rear direction of the transmission case 11 is set to coincide with the front-rear direction of the vehicle body, and the up-down direction of the transmission case 11 is set to coincide with the up-down direction of the vehicle body.

[0069] like Figure 2 As shown, the transmission 11 is equipped with an engine 3 (see Figure 1 ) converts the power of the forward and reverse switching device 20 into forward power and reverse power, a high-low speed switching device 30 that changes the forward power outputted from the forward and reverse switching device 20 into two stages of high and low speed, a gear transmission 40 to which the reverse power outputted from the forward and reverse switching device 20 and the forward power outputted from the high-low speed switching device 30 are inputted, a creeper transmission 60 that changes the power outputted from the gear transmission 40, a rear wheel differential mechanism 70 that transmits the power outputted from the gear transmission 40 and the power outputted from the creeper transmission 60 to the left and right rear wheels 2, and a rear wheel differential mechanism 70 that transmits the power outputted from the gear transmission 40 and the power outputted from the creeper transmission 60 to the left and right front wheels 1 (refer to Figure 1 ) output of the front wheel drive shaft 44.

[0070] The gear transmission 40 and the creeper speed change device 60 are provided at the rear side of the forward / reverse travel switching device 20 and the high / low speed switching device 30. The rear wheel differential mechanism 70 is provided at the rear side of the gear transmission 40 and the creeper speed change device 60.

[0071] In the gearbox 11, as Figure 2 As shown in FIG. 1 , the front split gearbox 11A is provided to accommodate the forward / reverse switching device 20, the high / low speed switching device 30, the gear transmission 40, the creeping gearbox 60 and the front wheel drive shaft 44, and the rear split gearbox 11B is provided to accommodate the differential mechanism 70 for the rear wheels. A power output box 71 supporting the power output shaft 13 is detachably connected to the rear portion of the rear split gearbox 11B. The power output box 71 accommodates the power output shaft 13 from the engine 3 (see FIG. 1 ). Figure 1 ) to the power output shaft 13. The power of the engine 3 is input to the working speed change device 72 via the rotating shaft 73, the working clutch 74 and the rotating shaft 75. Figure 2 The reference numeral 76 is a hydraulic pump driven by receiving power from the rotating shaft 73 .

[0072] [Regarding the structure of the forward / reverse switching device of the first embodiment]

[0073] In the forward and reverse switching device 20, as Figure 2 , 3 As shown, an engine 3 (see Figure 1 ) is input via an input shaft 21 through a main clutch 15, a clutch unit 22 assembled on the input shaft 21 and converting the power input to the input shaft 21 into forward power and reverse power, a forward output gear 23 as a forward output unit that outputs the converted forward power, and a reverse output gear 24 as a reverse output unit that outputs the converted reverse power.

[0074] In the present embodiment, the reverse output gear 24 is arranged at the front side of the clutch part 22, and the forward output gear 23 is arranged at the rear side of the clutch part 22. Without being limited to this, the reverse output gear 24 may be arranged at the rear side of the clutch part 22, and the forward output gear 23 may be arranged at the front side of the clutch part 22.

[0075] like Figure 2 , 3As shown, the clutch unit 22 includes a forward clutch 22F and a reverse clutch 22R mounted on the input shaft 21. The forward clutch 22F is provided on the rear side of the reverse clutch 22R. The reverse gear 26 is meshed with the output side member 25 and the reverse output gear 24 of the reverse clutch 22R. The reverse output gear 24 is linked to the output side member 25 via the reverse gear 26. The forward output gear 23 is linked to the output side member 27 of the forward clutch 22F. The forward output gear 23 and the output side member 27 are linked to each other by forming the forward output gear 23 and the output side member 27 as one piece.

[0076] In the present embodiment, the forward clutch 22F and the reverse clutch 22R are composed of hydraulically controlled wet multi-plate clutches, but are not limited thereto. The forward clutch 22F and the reverse clutch 22R may be dry multi-plate clutches, single-plate clutches, meshing clutches, or the like.

[0077] In the forward-reverse switching device 20, when the forward side clutch 22F is operated to the connected state, it becomes a forward transmission state, so that the power of the input shaft 21 is transmitted to the forward output gear 23 by the forward side clutch 22F and is output from the forward output gear 23. When the reverse side clutch 22R is operated to the connected state, it becomes a reverse transmission state, so that the power of the input shaft 21 is transmitted to the reverse gear 26 by the reverse side clutch 22R, and is transmitted from the reverse gear 26 to the reverse output gear 24, and is output from the reverse output gear 24.

[0078] A rotation transmission shaft 28 is provided across the reverse output gear 24 and the input shaft 41 as the input part of the gear transmission 40 to interlock and connect the reverse output gear 24 and the input shaft 41. A high / low speed switching device 30 is provided across the forward output gear 23 and the rotation transmission shaft 28.

[0079] When the forward-reverse switching device 20 is operated into the forward transmission state, the clutch part 22 transmits the power of the input shaft 21 to the forward output gear 23, and converts it into forward power with the help of the forward output gear 23. The converted forward power is input from the forward output gear 23 to the high-low speed switching device 30.

[0080] When the forward / reverse switching device 20 is operated to the reverse transmission state, the clutch unit 22 transmits the power of the input shaft 21 to the reverse gear 26, and converts it into reverse power through the reverse gear 26 and the reverse output gear 24, and the converted reverse power is transmitted from the reverse output gear 24 to the rotation transmission shaft 28. The reverse power output by the forward / reverse switching device 20 is input to the gear transmission 40 through the rotation transmission shaft 28. The reverse power output by the forward / reverse switching device 20 is input without speed change through the gear transmission 40.

[0081] [Regarding the Configuration of the High-Low Speed ​​Switching Device in the First Embodiment]

[0082] The high and low speed switching device 30 is as follows Figure 2 , 3 As shown, it is provided across the forward output gear 23 and the rotation transmission shaft 28, and changes the power of the forward output gear 23 into power having two different rotation speeds and transmits it to the rotation transmission shaft 28.

[0083] Specifically, the high-low speed switching device 30 is as follows: Figure 2 , 3 As shown, there are a high-speed side gear pair 31 for high-speed setting provided over the forward output gear 23 and the rotation transmission shaft 28, and a low-speed side gear pair 32 for low-speed setting provided over the forward output gear 23 and the rotation transmission shaft 28. The high-speed side gear pair 31 is composed of a gear portion 23a on the large-diameter side formed in a pair of gear portions 23a and 23b of the forward output gear 23, and a high-speed setting gear 31a supported on the rotation transmission shaft 28 in a state of meshing with the gear portion 23a on the large-diameter side. The low-speed side gear pair 32 is composed of a gear portion 23b on the small-diameter side of the pair of gear portions 23a and 23b of the forward output gear 23, and a low-speed setting gear 32a supported on the rotation transmission shaft 28 in a state of meshing with the gear portion 23b on the small-diameter side.

[0084] A high-speed side clutch 33 is provided across the high-speed setting gear 31a and the rotating transmission shaft 28. A low-speed side clutch 34 is provided across the low-speed setting gear 32a and the rotating transmission shaft 28. In the present embodiment, the high-speed side clutch 33 and the low-speed side clutch 34 are composed of a hydraulically controlled wet multi-plate clutch, but are not limited thereto. As the high-speed side clutch 33 and the low-speed side clutch 34, a dry multi-plate clutch, a single-plate clutch, a meshing clutch, etc. can be adopted.

[0085] In the high-low speed switching device 30, the high-speed side clutch 33 is operated to the connected state and the low-speed side clutch 34 is operated to the disconnected state to achieve a high-speed transmission state, and the high-speed side clutch 33 is operated to the disconnected state and the low-speed side clutch 34 is operated to the connected state to achieve a low-speed transmission state.

[0086] When the high-low speed switching device 30 is operated to the high-speed transmission state, the forward power of the forward output gear 23 is shifted to the high-speed side by the high-speed side gear pair 31 and transmitted to the rotating transmission shaft 28 by the high-speed side clutch 33, and is input to the gear transmission 40 by the rotating transmission shaft 28.

[0087] When the high-low speed switching device 30 is operated to the low-speed transmission state, the forward power of the forward output gear 23 is shifted to the low-speed side by the low-speed side gear pair 32 and transmitted to the rotating transmission shaft 28 by the low-speed side clutch 34, and is input to the gear transmission 40 by the rotating transmission shaft 28.

[0088] The rotational speed of the forward power when the high-low speed switching device 30 is operated to the high-speed transmission state and the forward power is input to the gear transmission 40, and the rotational speed of the reverse power when the forward-reverse switching device 20 is operated to the reverse transmission state and the reverse power is input to the gear transmission 40 are set to the same speed.

[0089] [Regarding the Structure of the Gear Transmission of the First Embodiment]

[0090] Gear transmission 40 Figure 4 As shown, it comprises a main transmission part 40A for shifting the power input by the rotating transmission shaft 28 into 6 speeds of 1st to 6th speeds, and an auxiliary transmission part 40B for shifting the power output by the main transmission part 40A into 2 speeds of high and low speeds for transmitting the power to the differential mechanism 70 for the rear wheels and the front wheel transmission shaft 44.

[0091] Specifically, the gear transmission 40 is as follows: Figure 2 , 4 As shown, an input shaft 41 as an input part linked to the rotating transmission shaft 28, a cylindrical transmission intermediate shaft 42 arranged parallel to the input shaft 41, an output shaft 43 arranged parallel to the transmission intermediate shaft 42, and a front wheel transmission shaft 44 arranged parallel to the output shaft 43. The rotating transmission shaft 28 and the input shaft 41 are arranged in a state of being located concentrically and arranged in a straight line. The rotating transmission shaft 28 and the input shaft 41 are linked to each other by externally engaging the spline shaft portion provided at the front part of the input shaft 41 with the rear part of the rotating transmission shaft 28. The transmission intermediate shaft 42 is externally fitted to the rotating shaft 73 so as to be relatively rotatable. Figure 5 The center line C shown in FIG. 1 represents the center of the vehicle body in the left-right direction. Figure 5 As shown, the transmission rotating shaft 42 and the output shaft 43 are arranged in the central part of the vehicle body in the left-right direction. The transmission rotating shaft 42 is arranged above the output shaft 43. The input shaft 41 is arranged laterally outward of the vehicle body than the transmission rotating shaft 42 and the output shaft 43. The input shaft 41 is arranged above the output shaft 43. The front wheel drive shaft 44 is arranged on the laterally outward side of the vehicle body opposite to the side where the input shaft 41 is located relative to the transmission rotating shaft 42 and the output shaft 43. The front wheel drive shaft 44 is arranged below the output shaft 43.

[0092] The main transmission unit 40A is as follows Figure 4As shown, it is provided over the input shaft 41 and the transmission rotating shaft 42 , and changes the power of the input shaft 41 into six levels of power having different rotational speeds from the first speed to the sixth speed, and transmits them to the transmission rotating shaft 42 .

[0093] Specifically, the main transmission unit 40A is as follows: Figure 4 As shown, the first speed gear pair 45 to the sixth speed gear pair 50 are provided over the input shaft 41 and the transmission rotating shaft 42, and the first shift gear 52a, the second shift gear 52b and the third shift gear 52c are supported along the input shaft 41 so as to be non-rotatable and slidable. The first speed gear pair 45 to the sixth speed gear pair 50 respectively have input shaft gears 45a to 50a supported on the input shaft 41 so as to be relatively rotatable, and the first shift gear 52a, the second shift gear 52b or the third shift gear 52c is engaged with the side of the input shaft gears 45a to 50a. When the input shaft gears 45a to 50a are linked to the input shaft 41 via the first shift gear 52a, the second shift gear 52b or the third shift gear 52c, they are in a speed change action state, so that the power of the input shaft 41 is changed in speed and transmitted to the transmission rotating shaft 42. The first to sixth speed gear pairs 45 to 50 are in a shift release state when the first shift gear 52a, the second shift gear 52b, or the third shift gear 52c is disengaged from the input shaft gears 45a to 50a and the interlocking connection with the input shaft 41 of the input shaft gears 45a to 50a is released.

[0094] The auxiliary transmission unit 40B is as follows Figure 4 As shown, it is arranged throughout the transmission intermediate shaft 42 and the output shaft 43, and the power of the transmission intermediate shaft 42 is changed into two levels of power with different rotation speeds of high and low speeds and transmitted to the output shaft 43, and then transmitted from the output shaft 43 to the differential mechanism 70 for the rear wheels and the front wheel drive shaft 44.

[0095] Specifically, the auxiliary transmission unit 40B is as follows: Figure 4 As shown, it includes a high-speed setting gear pair 53 arranged throughout the transmission rotating shaft 42 and the output shaft 43, a low-speed setting gear pair 54 arranged throughout the transmission rotating shaft 42 and the output shaft 43, and a fourth shift gear 55 supported on the output shaft 43 in a non-rotatable and slidable manner.

[0096] The high speed setting gear pair 53 includes a high speed setting intermediate shaft gear 53a which is supported in a non-rotatable manner on the transmission intermediate shaft 42, and a high speed setting output shaft gear 53b which is supported in a non-rotatable manner on the output shaft 43 while being meshed with the high speed setting intermediate shaft gear 53a. The high speed setting intermediate shaft gear 53a is composed of the intermediate shaft gears of the third speed gear pair 47 which are supported in a non-rotatable manner on the transmission intermediate shaft 42 and constitute the main transmission section 40A.

[0097] The low speed setting gear pair 54 includes a low speed setting intermediate shaft gear 54a supported non-rotatably on the transmission intermediate shaft 42, and a low speed setting output shaft gear 54b supported relatively rotatably on the output shaft 43 while meshing with the low speed setting intermediate shaft gear 54a.

[0098] In the auxiliary transmission part 40B, when the fourth shift gear 55 is engaged with the side of the high-speed setting output shaft gear 53b and is slid to the high-speed connection position disengaged from the low-speed setting output shaft gear 54b, a high-speed shift state is formed in which the power of the transmission shaft 42 is transmitted to the output shaft 43 via the high-speed setting gear pair 53. That is, the output shaft gear 53b is linked with the output shaft 43 via the fourth shift gear 55 to form a transmission connection state in which the power is transmitted to the output shaft 43, and the linkage connection of the output shaft gear 54b with respect to the output shaft 43 is released to form a transmission disconnection state in which the power transmission with respect to the output shaft 43 is cut off.

[0099] In the auxiliary transmission part 40B, when the fourth shift gear 55 is disengaged from the output shaft gear 53b of the high speed setting and is slid to the low speed connection position engaged with the side of the output shaft gear 54b of the low speed setting, the power of the transmission shaft 42 is transmitted to the output shaft 43 via the low speed setting gear pair 54. That is, the linkage connection of the output shaft gear 53b with respect to the output shaft 43 is released to form a transmission disconnection state in which the power transmission with respect to the output shaft 43 is cut off, and the output shaft gear 54b is linked to the output shaft 43 via the fourth shift gear 55 to form a transmission connection state in which the power is transmitted to the output shaft 43.

[0100] In the auxiliary transmission part 40B, when the fourth shift gear 55 is disengaged from the output shaft gear 53b set at a high speed and is slid to a neutral position disengaged from the output shaft gear 54b set at a low speed, a neutral state is formed in which the power transmission from the transmission rotating shaft 42 to the output shaft 43 is cut off. That is, the output shaft gear 53b is in a transmission cut-off state in which the interlocking connection with the output shaft 43 is released and the power transmission with respect to the output shaft 43 is cut off, and the output shaft gear 54b is in a transmission cut-off state in which the interlocking connection with the output shaft 43 is released and the power transmission with respect to the output shaft 43 is cut off. The auxiliary transmission part 40B can exert the speed change function of the creeper transmission device 60 by shifting to the neutral state.

[0101] like Figure 2 , 4 As shown, the rear portion of the output shaft 43 and the front portion of the input shaft 70a of the differential mechanism 70 are interlocked by a connecting member 56. A gear interlock mechanism 57 is provided across the rear portion of the output shaft 43 and the rear portion of the front wheel propeller shaft 44 to transmit the power of the output shaft 43 to the front wheel propeller shaft 44.

[0102] In the gear transmission 40, the power inputted to the input shaft 41 by the rotating transmission shaft 28 is mainly shifted by the gear pair operated in the shifting action state among the first speed gear pair 45 to the sixth speed gear pair 50 and is transmitted to the transmission rotating shaft 42, and is indirectly shifted by the auxiliary transmission part 40B switched to the high speed shift state or the low speed shift state and is transmitted to the output shaft 43, and is transmitted from the output shaft 43 to the differential mechanism 70 for the rear wheels and the front wheel transmission shaft 44. The power transmitted to the front wheel transmission shaft 44 is as follows: Figure 2 As shown, the rotating shaft 58 connected to the front part of the front wheel drive shaft 44 via the front wheel speed increasing mechanism 58a and the front wheel drive clutch 58b is driven to the front wheel drive box 59 (see Figure 1 ) input and transmitted to the left and right front wheels 1 by means of a front wheel differential mechanism (not shown) built into the front wheel drive box 59.

[0103] [Regarding the Structure of the Creep Shift Device According to the First Embodiment]

[0104] The creeper speed change device 60 is as follows Figure 2 , 4 As shown, it includes an output shaft 43 and a creeping shaft 61 as a rotating shaft arranged parallel to the output shaft 43. Figure 5 As shown, the creeper shaft 61 is provided on the vehicle body transversely outer side on the same side as the input shaft 41 relative to the transmission intermediate shaft 42 and the output shaft 43. The creeper shaft 61 is provided below the output shaft 43.

[0105] like Figure 4 As shown, the first reduction gear 62 is supported by the creeping shaft 61 so as to be relatively rotatable. The first reduction gear 62 meshes with the first transmission gear 66 which is provided on the side of the output shaft gear 54b so as not to be relatively rotatable. The outer diameter of the first reduction gear 62 is formed larger than the outer diameter of the first transmission gear 66. The power of the output shaft gear 54b is transmitted to the first reduction gear 62 by the first transmission gear 66 which rotates together with the output shaft gear 54b, and the first reduction gear 62 rotates. The power of the output shaft gear 54b is decelerated and transmitted to the first reduction gear 62.

[0106] The second reduction gear 63 is supported by the output shaft 43 so as to be relatively rotatable. The second reduction gear 63 meshes with the second transmission gear 67 which is provided on the side of the first reduction gear 62 so as to be non-rotatable. The outer diameter of the second reduction gear 63 is formed larger than the outer diameter of the second transmission gear 67. The power of the first reduction gear 62 is transmitted to the second reduction gear 63 by the second transmission gear 67 which rotates together with the first reduction gear 62, and the second reduction gear 63 rotates. The power of the first reduction gear 62 is reduced and transmitted to the second reduction gear 63.

[0107] The third reduction gear 64 is supported on the creeping shaft 61 so as to be non-rotatable relative to the creeping shaft 61. The third reduction gear 64 meshes with the third transmission gear 68 which is provided on the side of the second reduction gear 63 so as to be non-rotatable relative to the creeping shaft 61. The outer diameter of the third reduction gear 64 is formed to be larger than the outer diameter of the third transmission gear 68. The power of the second reduction gear 63 is transmitted to the third reduction gear 64 by the third transmission gear 68 which rotates together with the second reduction gear 63, and the third reduction gear 64 rotates, and the creeping shaft 61 rotates by means of the third reduction gear 64. The power of the second reduction gear 63 is reduced by the third reduction gear 64 and transmitted to the creeping shaft 61.

[0108] A reduction gear pair 65 is provided over the creeping shaft 61 and the output shaft 43. The reduction gear pair 65 is arranged on the side opposite to the side where the first reduction gear 62 is located with respect to the output shaft gear 54b in the direction along the axis of the creeping shaft 61. The reduction gear pair 65 is composed of a transmission gear 65a supported on the creeping shaft 61 so as to be relatively rotatable, and an output shaft reduction gear 65b supported on the output shaft 43 so as to be relatively non-rotatable while being meshed with the transmission gear 65a. The outer diameter of the output shaft reduction gear 65b is formed to be larger than the outer diameter of the transmission gear 65a.

[0109] A shift gear 69 as a clutch is provided between the transmission gear 65a and the creeper shaft 61. The shift gear 69 is supported by the creeper shaft 61 in a relatively non-rotatable and slidable manner.

[0110] In the reduction gear pair 65, the shift gear 69 is slid toward the connection position engaged with the side of the transmission gear 65a, whereby the transmission gear 65a is non-rotatably connected to the creeping shaft 61 by the shift gear 69 to form a transmission connection state, and the power of the creeping shaft 61 is reduced by the transmission gear 65a and the output shaft reduction gear 65b and transmitted to the output shaft 43.

[0111] In the reduction gear pair 65 , the shift gear 69 is slid to the disconnected position away from the transmission gear 65 a , thereby releasing the connection between the transmission gear 65 a and the creeper shaft 61 to form a transmission disconnected state, and power cannot be transmitted from the creeper shaft 61 to the output shaft 43 .

[0112] In the present embodiment, the reduction gear pair 65 is switched between the transmission on state and the transmission off state by switching the connection state and the connection release state of the transmission gear 65a relative to the creeping shaft 61, but the present invention is not limited thereto. Alternatively, a clutch may be used in which the transmission gear 65a is supported on the creeping shaft 61 so as not to be relatively rotatable, the output shaft reduction gear 65b is supported on the output shaft 43 so as to be relatively rotatable, and the connection state and the connection release state of the output shaft reduction gear 65b relative to the output shaft 43 are switched, thereby switching the reduction gear pair 65 between the transmission on state and the transmission off state. In addition, the clutch is not limited to the shift gear 69, and a friction clutch, a meshing clutch, etc. may be used.

[0113] In the creep speed change device 60, when the reduction gear pair 65 is operated to the transmission-on state, the creep shaft 61 and the output shaft 43 are linked by the reduction gear pair 65 and the shift gear 69 to form the speed change-on state, the power of the output shaft gear 54b is transmitted to the first reduction gear 62 by the first transmission gear 66, the power of the first reduction gear 62 is transmitted to the second reduction gear 63 by the second transmission gear 67, the power of the second reduction gear 63 is transmitted to the third reduction gear 64 by the third transmission gear 68, the creep shaft 61 is driven by the third reduction gear 64, and the power of the creep shaft 61 is transmitted to the output shaft 43 by the reduction gear pair 65. That is, the power of the output shaft gear 54b is transmitted to the output shaft 43 through the first stage deceleration of the first reduction gear 62, the second stage deceleration of the second reduction gear 63, the third stage deceleration of the third reduction gear 64, and the fourth stage deceleration of the reduction gear pair 65.

[0114] In the creep speed change device 60, when the reduction gear pair 65 is operated into the transmission cut-off state, the linkage connection between the creep shaft 61 and the output shaft 43 is released into the speed change cut-off state, and the power transmitted from the output shaft gear 53b and the output shaft gear 54b to the output shaft 43 via the fourth shift gear 55 can be directly transmitted from the output shaft 43 to the input shaft 70a of the differential mechanism 70.

[0115] In the traveling transmission device 14, when the forward / reverse switching device 20 is switched to the forward transmission state, the power of the engine 3 is converted into forward power by the forward / reverse switching device 20, and the converted forward power is input to the high / low speed switching device 30 and shifted to the low speed side or the high speed side, and the shifted forward power to the low speed side or the high speed side is input to the gear transmission 40 through the rotating transmission shaft 28 and the input shaft 41. When the forward / reverse switching device 20 is switched to the reverse transmission state, the power of the engine 3 is converted into reverse power by the forward / reverse switching device 20, and the converted reverse power is input to the gear transmission 40 through the rotating transmission shaft 28 and the input shaft 41. The forward power or reverse power input to the gear transmission 40 is transmitted to the output shaft 43 via the main transmission section 40A and the auxiliary transmission section 40B, and is input from the output shaft 43 to the differential mechanism 70 for the rear wheels and transmitted to the left and right rear wheels 2. The power is transmitted from the output shaft 43 to the front wheel propeller shaft 44 , and is input from the front wheel propeller shaft 44 to the front wheel drive box 59 and transmitted to the left and right front wheels 1 .

[0116] Therefore, in the case of loading operations, the front wheels 1 and the rear wheels 2 are switched to the forward side and the reverse side and driven, and the vehicle can switch between forward travel and reverse travel by simply switching the forward / reverse switching device 20 to the forward transmission state and the reverse transmission state. When the high / low speed switching device 30 is switched to the high speed transmission state, the rotation speed of the reverse power input to the gear transmission 40 by the rotating transmission shaft 28 and the input shaft 41 when the forward / reverse switching device 20 is switched to the reverse transmission state and the rotation speed of the forward power input to the gear transmission 40 by the rotating transmission shaft 28 and the input shaft 41 when the forward / reverse switching device 20 is switched to the forward transmission state are the same speed, and the forward travel and reverse travel can be performed at the same travel speed.

[0117] During normal travel, the creeper transmission 60 is switched to the gear-shift cutoff state. Thus, the power input to the gear transmission 40 is mainly shifted by the main transmission part 40A and sub-shifted by the sub-transmission part 40B and transmitted to the output shaft 43, and is transmitted to the front wheels 1 and the rear wheels 2 without performing a speed change by the creeper transmission 60.

[0118] When plowing is performed, the auxiliary transmission part 40B is switched to a neutral state and the creeping transmission device 60 is switched to a shift-on state. In this way, the power input to the gear transmission 40 and shifted by the main transmission part 40A is input to the creeping transmission device 60 from the output shaft gear 54b of the auxiliary transmission part 40B with a low speed setting via the first transmission gear 66. In the creeping transmission device 60, the power is creep-shifted through four levels of deceleration, namely, the deceleration of the first reduction gear 62, the deceleration of the second reduction gear 63, the deceleration of the third reduction gear 64, and the deceleration of the reduction gear pair 65, and is transmitted to the output shaft 43. The power is transmitted from the output shaft 43 to the differential mechanism 70 for the rear wheels and the front wheel drive shaft 44, so that the front wheels 1 and the rear wheels 2 can be driven at a low speed. In this embodiment, the vehicle can travel at a speed of about 0.2 km / h.

[0119] In this embodiment, if Figure 5 As shown, the creeper shaft 61 is disposed on the same side as the input shaft 41 relative to the center line C, and the front wheel propeller shaft 44 is disposed on the opposite side to the input shaft 41 relative to the center line C. Since the interval between the creeper shaft 61 and the center line C needs to be wider than the interval between the front wheel propeller shaft 44 and the center line C, the interval between the gear supported by the output shaft 43 and the side wall portion 11S of the transmission case 11 can be narrowed compared to the case where the creeper shaft 61 is disposed on the opposite side to the input shaft 41 relative to the center line C. If the interval between the gear and the side wall portion 11S is narrow, the lubricating oil in the transmission case is easily stirred by the rotating gear, and the lubricating oil easily reaches the gears of the transmission intermediate shaft 42 and the input shaft 41 located above the output shaft 43. Therefore, in the case of this embodiment, the oil level in the transmission case can be made as low as possible and the lubricating oil can easily reach the entire gear transmission 40.

[0120] [Another embodiment of the first embodiment]

[0121] (1) Figure 6 1 is a longitudinal sectional side view showing a travel transmission device 94 according to another embodiment. In the travel transmission device 94 according to another embodiment, the high-low speed switching device 30 is omitted.

[0122] In the forward / reverse switching device 20 of the traveling transmission device 94, when the forward clutch 22F is switched to the on state, the power of the input shaft 21 is transmitted to the input shaft 41 of the gear transmission 40 via the forward clutch 22F, the clutch output gear 80, and the input gear 81. When the reverse clutch 22R is switched to the on state, the power of the input shaft 21 is transmitted to the input shaft 41 of the gear transmission 40 via the reverse clutch 22R, the clutch output gear 82, the reverse gear 83, the rotating shaft 84, the transmission gear 85, and the input gear 81.

[0123] (2) Figure 2 The traveling transmission device 14 and Figure 6 In the illustrated traveling transmission device 94 , the forward / reverse switching device 20 is provided outside the gear transmission 40 , but the gear transmission 40 may also have a forward / reverse switching function.

[0124] (3) In the above embodiment, an example is shown in which the reduction gear pair 65 is arranged on the side opposite to the side where the first reduction gear 62 is located relative to the output shaft gear 54b, but the reduction gear pair 65 can also be arranged on the same side as the side where the first reduction gear 62 is located relative to the output shaft gear 54b.

[0125] [Second embodiment]

[0126] Hereinafter, an embodiment (second embodiment) as an example of the present invention will be described based on the drawings.

[0127] In the following description, the body of the tractor will be Figure 7 The direction of the arrow F shown is set to the "front of the vehicle body", the direction of the arrow B is set to the "rear of the vehicle body", the direction of the arrow U is set to the "above the vehicle body", the direction of the arrow D is set to the "below the vehicle body", the direction of the front side of the paper is set to the "left side of the vehicle body", and the direction of the back side of the paper is set to the "right side of the vehicle body".

[0128] [About the whole tractor of the second embodiment]

[0129] like Figure 7 As shown, the tractor has a vehicle body, and the vehicle body is equipped with a pair of left and right front wheels 101 as a travel device in a drivable and swingable manner, and a pair of left and right rear wheels 102 as a travel device in a drivable manner. A power unit 104 having an engine 103 is formed at the front of the vehicle body. A driving unit 107 is formed at the rear of the vehicle body, and the driving unit 107 has a driver's seat 105 and a steering wheel 106 for steering the front wheels 101. The driving unit 107 is equipped with a cab 107a covering the riding space. A linkage mechanism 109 that can connect various working devices in a lifting and lowering manner is equipped at the rear of the vehicle body frame 108.

[0130] The vehicle body frame 108 includes an engine 103, a clutch housing 110 connected to the rear of the engine 103, a transmission case 111 connected to the clutch housing 110 at the front, a left axle box 112 extending laterally outwardly to the left from the rear of the transmission case 111 to rotatably support the left rear wheel 102, a right axle box 112 extending laterally outwardly to the right from the rear of the transmission case 111 to rotatably support the right rear wheel 102, and a front wheel support frame 113 extending forward from the engine 103 to support the left and right front wheels 101. The left and right front wheels 101 of the front wheel support frame 113 are supported via a front wheel drive box 114.

[0131] In the tractor, a plow (not shown) and a rotary tillage device (not shown) are connected to the rear of the vehicle body via a linkage mechanism 109, forming a riding type tillage machine. A front loading device (not shown) is connected to the front of the vehicle body, forming a loading work machine. In this way, various work machines are connected to the vehicle body, forming various work machines. The power output of the engine 103 is transmitted from the power output shaft 115 provided at the rear of the transmission 111 to the work device connected to the rear of the vehicle body.

[0132] [Regarding the Structure of the Traveling Transmission Device of the Second Embodiment]

[0133] The driving transmission device 116 that transmits the power of the engine 103 to the front wheels 101 and the rear wheels 102 is as follows: Figure 8 The traveling transmission device 116 includes a gearbox 111. In the traveling transmission device 116, the front-rear direction of the gearbox 111 is set to coincide with the front-rear direction of the vehicle body, and the up-down direction of the gearbox 111 is set to coincide with the up-down direction of the vehicle body. The gearbox 111 is configured to be divisible into a front split gearbox 111a and a rear split gearbox 111b.

[0134] In front of the gearbox 111, the engine 103 (refer to Figure 7 ) is rotatably supported by a transmission input shaft 118 to which the power is transmitted via a main clutch 117. A differential mechanism 119 capable of transmitting power to the axle 102a on the left rear side and the right rear side is built into the rear part of the transmission 111. A transmission 120 is provided throughout the front and rear parts of the transmission 111 to change the speed of the power transmitted to the transmission input shaft 118 and transmit it to the differential mechanism 119.

[0135] like Figure 8As shown, the transmission 120 is equipped with a high-low speed switching device 120A, a forward-reverse switching device 120B, a speed change device 120C, an auxiliary speed change device 120D, and a creep speed change device 120E. The high-low speed switching device 120A changes the power transmitted to the transmission input shaft 118 into power on the high-speed side and power on the low-speed side. The forward-reverse switching device 120B converts the high-speed side power and the low-speed side power output by the high-low speed switching device 120A into forward power and reverse power. The speed change device 120C mainly changes the forward power and reverse power output by the forward-reverse switching device 120B into a speed change power with multiple different rotational speeds. The auxiliary speed change device 120D sub-changes the power output by the speed change device 120C into a speed change power with two different rotational speeds of high and low speeds. The creep speed change device 120E creeps the power output by the auxiliary speed change device 120D. In the present embodiment, the transmission 120C is configured to be capable of six speed changes from the first speed to the sixth speed. However, the present invention is not limited thereto, and a transmission capable of five or less speeds or seven or more speeds may be employed.

[0136] like Figure 8 As shown, the shift gear 122 is supported in a non-rotatable and slidable manner at the support portion 121 formed on the differential mechanism input shaft 119a of the differential mechanism 119. A gear portion 123a is formed at the rear portion of the auxiliary transmission output shaft 123 of the auxiliary transmission device 120D. The second crawling gear 124 of the creeping transmission device 120E is supported in a relatively rotatable manner on the differential mechanism input shaft 119a. When the shift gear 122 is engaged throughout the support portion 121 and the gear portion 123a, the engagement between the shift gear 122 and the second crawling gear 124 is disengaged, and the auxiliary transmission output shaft 123 and the differential mechanism input shaft 119a are linked and connected by the shift gear 122, and the power of the auxiliary transmission output shaft 123 is input to the differential mechanism 119 without changing speed. When the shift gear 122 is engaged with the supporting portion 121 and the side of the second crawler gear 124, the engagement between the shift gear 122 and the gear portion 123a is disengaged, and the second crawler gear 124 and the differential mechanism input shaft 119a are linked and connected by the shift gear 122, and the power of the auxiliary transmission output shaft 123 is creep-shifted by the creeper transmission device 120E and input into the differential mechanism 119.

[0137] The power of the differential mechanism input shaft 119a is transmitted to the front wheel output shaft 126 via the gear mechanism 125, and the power of the front wheel output shaft 126 is transmitted to the front wheel output shaft 126 via the front wheel clutch 127 and the front wheel drive shaft 128 (see Figure 7 ) is driven by the front wheel drive box 114 (refer to Figure 7 )enter.

[0138] Figure 8Reference numeral 129 denotes a working speed change device. The working speed change device 129 receives power from the transmission input shaft 118 through a rotating shaft 129 a and transmits the input power to the power output shaft 115 after the speed of the input power is changed.

[0139] [Regarding the Structure of the Braking Device of the Second Embodiment]

[0140] like Figure 7 As shown in FIG. 1 , a left brake device 130 for braking the left rear wheel 102 and a right brake device 130 for braking the right rear wheel 102 are provided at the rear portion of the vehicle frame 108. The left brake device 130 and the right brake device 130 have different structures in that the left brake device 130 is provided at the left lateral side of the vehicle frame 108 and the right brake device 130 is provided at the right lateral side of the vehicle frame 108, but have the same structure in other aspects. Only the left brake device 130 will be described below.

[0141] like Fig. 9 , 10 As shown, a box support portion 111c is provided on the left lateral side of the transmission case 111, and the axle box 112 is connected to the box support portion 111c by a plurality of connecting bolts 140. The axle box 112 rotatably supports the axle 102a of the left rear wheel 102. In the present embodiment, the output shaft 119b and the axle 102a are linked and connected via a planetary gear mechanism 141 that decelerates the power of the output shaft 119b of the differential mechanism 119 and transmits it to the axle 102a, and the ring gear 141a of the planetary gear mechanism 141 is installed between the box support portion 111c and the axle box 112. It is not limited to this, for example, it is also possible that the output shaft 119b of the differential mechanism 119 and the axle 102a are connected by a connecting member so as not to rotate relative to each other, and there is no component installed between the box support portion 111c and the axle box 112.

[0142] The left brake device 130 is built into the gearbox 111 of the vehicle frame 108. Specifically, Fig. 9 As shown, the brake device 130 on the left side has a brake disc 131, a disc receiving portion 132, and a rotating cam 133 that pushes the brake disc 131 toward the disc receiving portion 132. The brake disc 131, the disc receiving portion 132, and the rotating cam 133 are built into the case support portion 111c of the transmission case 111. In this embodiment, a brake device 130 having four brake discs 131 is used. This is not limited to this, and a brake device having less than three or more than five brake discs 131 may also be used.

[0143] The four brake discs 131 are respectively engaged with the spline shaft 119d of the output shaft 119b of the differential mechanism 119 in a manner that they cannot rotate relative to each other but can slide. The disc receiving portion 132 is embedded in the box support portion 111c. The disc receiving portion 132 is positioned at the assembly position of the box support portion 111c by clamping the outer peripheral side portion of the disc receiving portion 132 by the positioning portion 134 and the ring gear 141a provided in the box support portion 111c. The rotating cam 133 is externally embedded in the flange portion 142a of the cam support portion 142 provided in the transmission case 111 in a manner that it can rotate relative to each other and can slide.

[0144] In the left brake device 130, the rotating cam 133 is rotated toward the on position by the brake operating unit 150 having the brake operating member 151 disposed on the left lateral outer side of the transmission case 111, thereby becoming the on state, and the left rear wheel 102 (refer to Figure 7 ) is applied with a brake. That is, when the rotating cam 133 is rotated toward the on position, the rotating cam 133 is pushed toward the brake disc 131 by the cam member 142b of the cam support portion 142, and the brake disc 131 is pushed toward the disc receiving portion 132 by the rotating cam 133. The brake disc 131 pushed toward the disc receiving portion 132 receives the brake of the disc receiving portion 132 and applies a brake action to the output shaft 119b, thereby applying a brake action to the axle 102a via the planetary gear mechanism 141. The brake reaction force applied to the disc receiving portion 132 is received by the box support portion 111c via the ring gear 141a and the connecting bolt 140.

[0145] In the left brake device 130, the rotating cam 133 is rotated toward the cut-off position by the brake operating unit 150, thereby entering the cut-off state, releasing the brake force relative to the left rear wheel 102 (see Figure 7 That is, when the rotating cam 133 is in the cut-off position, the rotating cam 133 of the cam member 142b releases the pressure on the brake disc 131, and the brake disc 131 releases the pressure on the disc receiving portion 132. The brake disc 131 whose pressure on the disc receiving portion 132 is released releases the braking action on the output shaft 119b, and releases the braking action on the axle 102a.

[0146] [Regarding the Structure of the Brake Operation Section of the Second Embodiment]

[0147] The brake operating unit 150 is as follows: Fig. 9 As shown, the brake operating member 151 provided outside the transmission case 111 , the cam operating arm 152 provided inside the transmission case 111 , and the rotation support shaft 154 supported by the side wall portion 111 d of the transmission case 111 are provided.

[0148] The cam operating arm 152 is provided in a state where the free end of the cam operating arm 152 is engaged with the operating portion 133a of the rotating cam 133. The rotating support shaft 154 is mounted in the through hole 153 of the side wall portion 111d via a boss member 155 that is relatively rotatably fitted to the rotating support shaft 154. The rotating support shaft 154 is relatively rotatably supported on the side wall portion 111d via the boss member 155. The through hole 153 is connected to the boss portion 111e (see FIG. 15A ) of the side wall portion 111d. Fig.10 ) is partially opened. The boss portion 111e is as shown in FIG. Fig.10 As shown, it is formed in a state where the upper part of the box support part 111c is connected to the outer peripheral side part. The base of the brake operating member 151 is connected to the end of the rotating support shaft 154 outside the transmission case so as to be non-rotatable relative to each other. The brake operating member 151 and the rotating support shaft 154 are connected by welding. The base of the cam operating arm 152 is connected to the end of the rotating support shaft 154 inside the transmission case so as to be non-rotatable relative to each other. The cam operating arm 152 and the rotating support shaft 154 are connected to each other so as to be non-rotatable relative to each other by the cam operating arm 152 being engaged with the spline shaft part 154a of the rotating support shaft 154. The cam operating arm 152 is clamped by the stop wheel 156 and the boss part 155, thereby positioning the cam operating arm 152 relative to the rotating support shaft 154. The cam operating arm 152 and the brake operating member 151 are linked and connected by the rotating support shaft 154. The cam operating arm 152 and the brake operating member 151 are supported by the side wall portion 111 d via the rotation support shaft 154 so as to be able to swing relative to the transmission case 111 with the axis P of the rotation support shaft 154 serving as a swing fulcrum.

[0149] Boss component 155 such as Fig. 9 As shown in FIG. 15 , the lateral wall 111d is fixed to the lateral wall 111d in a state of passing through the through hole 153. Fig.10 As shown, a threaded portion is formed on the outer periphery of the boss member 155. The boss member 155 is fixed to the side wall portion 111d by screwing the threaded portion of the boss member 155 into the threaded portion formed in the through hole. The flange portion 155a provided at the end of the boss member 155 on the brake operating member side is pushed toward the outer side surface of the side wall portion 111d to position the boss member 155 relative to the side wall portion 111d. In the present embodiment, as a fixing means for fixing the boss member 155 to the side wall portion 111d, a structure in which the boss member 155 is screwed into the side wall portion 111d is adopted, but it is not limited thereto. For example, a structure in which a threaded member is assembled at a portion of the boss member 155 protruding from the side wall portion 111d toward the inner side of the transmission case 111, and the side wall portion 111d is clamped by the threaded member and the flange portion 155a. Alternatively, a structure may be adopted in which screw components are mounted on the portion of the boss member 155 protruding from the side wall portion 111d toward the inside of the transmission case 111 and the portion protruding from the side wall portion 111d toward the outside of the transmission case 111, and the side wall portion 111d is clamped by the screw components on both the inside and outside.

[0150] In this embodiment, the axle box 112 can be connected to the transmission case 111 in a state where the brake device 130 and the brake operating unit 150 are assembled, so that the assembly work of the brake device 130 and the brake operating unit 150 and the assembly work of the axle box 112 can be performed separately. In this embodiment, the boss member 155 is used, but it is also possible to use a structure in which the rotating support shaft 154 is directly supported by the side wall portion 111d instead of the boss member 155.

[0151] like Fig. 9 As shown, the cam operating arm side portion 155b of the boss member 155 protrudes from the side wall portion 111d toward the inside of the transmission case 111 and abuts against the base end side portion of the cam operating arm 152. A gap S1 is provided between the cam operating arm 152 and the side wall portion 111d by the cam operating arm side portion 155b of the boss member 155. The inner side of the transmission case 111 cannot be processed by grinding or the like, and the inner surface of the side wall portion 111d is in a state of a casting surface, but the cam operating arm 152 swings smoothly without abutting against the inner surface of the side wall portion 111d due to the gap S1.

[0152] like Fig. 9 As shown, the flange portion 155a of the brake operating member side portion of the boss member 155 protrudes from the side wall portion 111d to the outside of the transmission case 111 and abuts against the base end side portion of the brake operating member 151. A gap S2 is provided between the brake operating member 151 and the side wall portion 111d by the flange portion 155a of the boss member 155. The gap S2 prevents a connecting member such as a linkage rod connecting a brake pedal (not shown) to the brake operating member 151 from contacting the side wall portion 111d and enables the connecting member to be connected to the brake operating member 151.

[0153] The positioning of the cam operating arm 152 relative to the side wall portion 111d and the positioning of the brake operating member 151 relative to the side wall portion 111d are performed by the boss component 155, so that the positional relationship between the cam operating arm 152 and the rotating cam 133 is maintained in a positional relationship in which the free end of the cam operating arm 152 appropriately acts on the operating portion 133a of the rotating cam 133.

[0154] In the brake operating unit 150, the brake operating member 151 is swung with the axis P of the rotating support shaft 154 as a swing fulcrum, thereby rotating the rotating support shaft 154. Figure 7As shown, when viewed from the side of the vehicle body, it is located above and in front of the axle center X of the axle 102a. The brake operating member 151 swings smoothly without contacting the outer side surface of the side wall portion 111d due to the gap S2, and the rotating support shaft 154 is smoothly rotated. When the rotating cam 133 is rotated, the cam operating arm 152 is swung by the rotating support shaft 154. The cam operating arm 152 swings smoothly without contacting the inner side surface of the casting surface of the side wall portion 111d due to the gap S1. When the cam operating arm 152 is swung, the operating portion 133a of the rotating cam 133 is pushed by the free end of the cam operating arm 152, and the rotating cam 133 is rotated.

[0155] like Fig. 9 , 10 As shown, the upper wall portion 111f of the transmission case 111 is provided with a working port 160 which opens to a portion corresponding to the upper side of the cam operating arm 152, and a cover 161 which closes the working port 160 in normal conditions and opens the working port 160 when the working port 160 is used. The working port 160 is arranged so that the boss portion 111e and the brake operating member 151 are located laterally outside the working port 160. The cover 161 is opened and closed by being attached or detached from the upper wall portion 111f. When performing assembly work or inspection work of the brake device 130, a tool or a hand can be inserted from the outside of the transmission case 111 through the working port 160 to perform work on the cam operating arm 152, the stopper wheel 156, etc.

[0156] [Another embodiment of the second embodiment]

[0157] (1) In the above embodiment, an example is shown in which the through hole 153 opens to the portion of the side wall portion 111 d having the boss portion 111 e , but the embodiment may also be implemented without the boss portion 111 e .

[0158] (2) In the above embodiment, the brake device 130 including four brake discs 131 is used. However, a brake device including three or less or five or more brake discs 131 may be provided.

[0159] (3) In the above embodiment, the front wheels 101 and the rear wheels 102 are installed, but a half-track may be installed.

[0160] Industrial Applicability

[0161] The present invention can be applied to a tractor including a half-track instead of the front wheels and the rear wheels.

[0162] Description of the attached figure

[0163] [First embodiment]

[0164] 3 Engine

[0165] 11 Gearbox

[0166] 20 Forward and reverse switching device

[0167] 22 Clutch unit

[0168] 23 forward output unit (forward output gear)

[0169] 24 Reverse output part (reverse output gear)

[0170] 28 Rotating transmission shaft

[0171] 30 High and low speed switching device

[0172] 40 gear transmission

[0173] 41 Input part (input shaft)

[0174] 54b output shaft gear

[0175] 60 creeper gear

[0176] 61 intermediate shaft (creeping shaft)

[0177] 62 1st reduction gear

[0178] 63 2nd reduction gear

[0179] 64 3rd reduction gear

[0180] 65 reduction gear pair

[0181] 66 1st transmission gear

[0182] 67 2nd transmission gear

[0183] 68 3rd transmission gear

[0184] 69 reduction gear pair

[0185] 70 Differential Mechanism

[0186] [Second embodiment]

[0187] 102a Axle

[0188] 108 body frame

[0189] 111 Gearbox

[0190] 111d side wall

[0191] 111f Upper wall

[0192] 112 Axle Box

[0193] 119 Differential Mechanism

[0194] 130 Braking device

[0195] 131 brake disc

[0196] 132 tray receiving department

[0197] 133 Rotating cam

[0198] 140 connecting bolt

[0199] 151 Brake operating parts

[0200] 152 Cam operating arm

[0201] 153 through holes

[0202] 154 Rotating support shaft

[0203] 155 boss parts

[0204] 155a Brake operating member side portion (flange portion)

[0205] 155b Cam operating arm side part

[0206] 160 operation ports

[0207] 161 cover body.

Claims

1. A driving transmission device for a tractor, characterized in that: Equipped with gear transmission, creeper transmission, gearbox, The gear transmission receives the power of the engine and outputs it after changing the speed. The creeper transmission receives the output of the gear transmission, decelerates the input power and outputs it to the differential mechanism for the rear wheels. The gearbox accommodates the gear transmission and the creeper gear shift device. The gear transmission includes an output shaft and an output shaft gear. The output shaft transmits power to the differential mechanism. The output shaft gear is supported by the output shaft and can be switched between a transmission-on state in which the gear is non-rotatably engaged with the output shaft and transmits power to the output shaft, and a transmission-off state in which the engagement with the output shaft is released and the power transmission to the output shaft is cut off. The creeper transmission device comprises an intermediate shaft, a first transmission gear, a first reduction gear, a second transmission gear, a second reduction gear, a third transmission gear, a third reduction gear, and a reduction gear pair. The aforementioned intermediate shaft is parallel to the aforementioned output shaft. The first transmission gear is arranged on the output shaft gear so as to be non-rotatable relative to the output shaft gear. The first reduction gear is supported by the intermediate shaft so as to be relatively rotatable while meshing with the first transmission gear, and rotates at a speed lower than that of the first transmission gear. The second transmission gear is arranged on the first reduction gear so as to be non-rotatable relative to the first reduction gear. The second reduction gear is supported by the output shaft so as to be relatively rotatable while meshing with the second transmission gear, and rotates at a speed lower than that of the second transmission gear. The third transmission gear is arranged on the second reduction gear so as to be non-rotatable relative to the second reduction gear. The third reduction gear is supported on the intermediate shaft in a state of being meshed with the third transmission gear so as to be non-rotatable relative to the intermediate shaft, and rotates at a speed lower than that of the third transmission gear. The reduction gear pair is arranged over the intermediate shaft and the output shaft, and can be switched between a transmission-on state in which the power of the intermediate shaft is decelerated and transmitted to the output shaft, and a transmission-off state in which the power transmission to the output shaft is cut off. In the direction along the axis of the intermediate shaft, the reduction gear pair is located on the side opposite to the side where the first reduction gear is located with respect to the output shaft gear.

2. The tractor travel transmission device according to claim 1, characterized in that: The intermediate shaft is arranged below the output shaft. A clutch for switching the reduction gear pair between the transmission-on state and the transmission-off state is provided across the transmission gear supported on the intermediate shaft in the reduction gear pair and the intermediate shaft.

3. The tractor travel transmission device according to claim 1, characterized in that: Equipped with forward and reverse switching device, rotating transmission shaft, high and low speed switching device, The forward-reverse switching device comprises a clutch part, the clutch part receives the power of the engine and converts the input power into forward power and reverse power, and the forward-reverse switching device comprises a forward output part for outputting the converted forward power and a reverse output part for outputting the converted reverse power, respectively. The rotation transmission shaft is provided across the reverse output portion and the input portion of the gear transmission to transmit the power of the reverse output portion to the input portion. The high-low speed switching device is arranged throughout the forward output unit and the rotating transmission shaft, and can switch between a high-speed transmission state in which the power of the forward output unit is shifted to the high-speed side to be transmitted to the rotating transmission shaft, and a low-speed transmission state in which the power of the forward output unit is shifted to the low-speed side to be transmitted to the rotating transmission shaft.

4. The tractor travel transmission device according to claim 2, characterized in that: Equipped with forward and reverse switching device, rotating transmission shaft, high and low speed switching device, The forward-reverse switching device comprises a clutch part, the clutch part receives the power of the engine and converts the input power into forward power and reverse power, and the forward-reverse switching device comprises a forward output part for outputting the converted forward power and a reverse output part for outputting the converted reverse power, respectively. The rotation transmission shaft is provided across the reverse output portion and the input portion of the gear transmission to transmit the power of the reverse output portion to the input portion. The high-low speed switching device is arranged throughout the forward output unit and the rotating transmission shaft, and can switch between a high-speed transmission state in which the power of the forward output unit is shifted to the high-speed side to be transmitted to the rotating transmission shaft, and a low-speed transmission state in which the power of the forward output unit is shifted to the low-speed side to be transmitted to the rotating transmission shaft.

5. The traveling transmission device for a tractor according to claim 3, characterized in that: The rotation transmission shaft and the input portion are concentrically arranged and arranged in a straight line.

6. The traveling transmission device for a tractor according to claim 4, characterized in that: The rotation transmission shaft and the input portion are concentrically arranged and arranged in a straight line.

7. The tractor travel transmission device according to any one of claims 3 to 6, characterized in that: The reverse output portion is disposed on the front side of the clutch portion, and the forward output portion is disposed on the rear side of the clutch portion.

Images