JP2017180659A - Working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rust prevention with respect to a brake operation shaft which is arranged while penetrating an axle case.SOLUTION: A brake operation shaft 94 for operating a brake mechanism 74 is made to penetrate an axle case 78, a brake arm 95 is connected to the brake operation shaft 94 at the outside of the axle case 78, a collar 101 is attached between a boss part 95a of the brake arm 95 and the axle case 78, a through-hole 102 is protrusively formed at an external periphery of the collar 101, a grease nipple 103 is arranged in the through-hole 102, the collar 101 is made to approximate a wall face of the axle case 78 so as to contact therewith and abut thereon, and an air space L for grease charge or grease transition is formed at an internal peripheral face of the collar 101. In the collar 101, a collar main body part 101a and a friction prevention auxiliary ring part 101b are arranged while making an O-ring 106 interposed therebetween, and the auxiliary ring part 101b is made to contact with and abut on the axle case 78.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a work vehicle such as an agricultural tractor, and more particularly to a waterproof structure of a brake operating shaft portion of a brake mechanism including a multi-plate brake.

  A conventional brake mechanism including a multi-plate brake is provided by penetrating a brake operation shaft through a brake case or an axle case, and brake operating force transmitted to a brake arm outside the case via the brake operation shaft is applied to a brake cam inside the case. It is configured to transmit to the mechanism. The brake operation shaft is configured to finish the cylindrical through hole of the brake case or axle case and directly support the brake operation shaft in a freely rotatable manner (Patent Document 1).

Japanese Utility Model Publication No. 56-166333

  By the way, according to Patent Document 1, as described above, the support structure of the brake operation shaft is a structure in which the cylindrical through hole of the brake case or the axle case is finished and the brake operation shaft is directly supported rotatably. Even if the side of the brake arm is in contact with the outer wall of the case, it is difficult to avoid the intrusion of muddy water into the case through-hole. As a result, rusting of the brake operating shaft may occur, which may hinder accurate brake operation.

  In view of the above, the present invention aims to improve rust prevention with respect to a brake operating shaft disposed through an axle case.

  In order to solve the above problems, the present invention has taken the following technical means.

  According to the first aspect of the present invention, a brake operating shaft 94 for operating a brake mechanism 74 provided in the axle case 78 is rotatably provided through the axle case 78, and the brake operating shaft is provided outside the axle case 78. 94, a brake arm 95 is connected, and a collar 101 is mounted between the boss 95a of the brake arm 95 and the axle case 78, and a through hole 102 is formed in the outer periphery of the collar 101. The work vehicle is provided with a grease nipple 103 and the collar 101 is brought close to contact with the wall surface of the axle case 78 so that the inner peripheral surface of the collar 101 has a grease filling or grease transfer gap L formed therein. .

  When grease is injected from the grease nipple 103, it reaches the inner periphery of the collar 101, and the opening of the through hole 102 for supporting the brake operating shaft 94 of the axle case 78 can be closed by filling the grease. For this reason, infiltration of muddy water or the like into the rear axle case 78 can be prevented. In addition, by providing the collar 101 itself and bringing the rear axle case 78 side of the collar 101 into contact with the case wall surface, it is possible to prevent foreign matter from colliding with the brake operating shaft 94 and to prevent direct intrusion of muddy water. Prevent and eliminate most.

  The invention according to claim 2 is that in claim 1, shims 105, 105... Are interposed between the collar 101 and the boss portion 95 a of the brake arm 95.

  According to a third aspect of the present invention, in the collar 101 of the first aspect, the collar 101 is provided with the collar main body portion 101a and the auxiliary ring portion 101b for preventing wear via the O-ring 106, and the auxiliary ring portion 101b is provided in the axle case 78. I will be in contact with you.

  According to a fourth aspect of the present invention, in the third aspect, the auxiliary ring portion 101b is fitted on the outer periphery of the collar main body portion 101a, and the O-ring 106 is provided between the two.

  The invention according to claim 5 is the invention according to claim 4, wherein the outer diameter of the collar main body portion 101a is made different and the auxiliary ring portion 101b is fitted to the smaller diameter side, and the step between the large diameter and the small diameter of the collar main body portion 101a. Shims 107, 107... Are interposed between the wall portion and the auxiliary ring portion 101b.

  The invention according to claim 6 is the auxiliary ring portion 101d between the collar main body portion 101c and the wall surface of the axle case 78 among the color main body portion 101c and the auxiliary ring portion 101d constituting the collar 101. Are arranged in a sandwiched manner, and an O-ring 108 is interposed between the collar main body portion 101c and the auxiliary ring portion 101d.

  According to the first aspect of the present invention, it is possible to block the opening of the through hole 102 for supporting the brake operating shaft 94 of the axle case 78 by filling the grease, and therefore, the intrusion of muddy water or the like into the rear axle case 78 is prevented. it can. Further, by providing the collar 101 itself and arranging the rear axle case 78 side of the collar 101 in contact with the case wall surface, it is possible to prevent foreign matter from colliding with the brake operating shaft 94 and to directly enter muddy water. Can be prevented.

  According to the second aspect of the invention, in addition to the effect of the first aspect, the contact pressure to the rear axle case 78 always acts, and the intrusion of the muddy water into the through hole 102 can be more effectively prevented.

  According to the third to sixth aspects of the invention, the auxiliary ring portion 101b contacts the axle case 78, but the collar main body portion 101a can be non-contact, and the auxiliary ring portions 101b and 101d are used as consumables. By exchanging, the color main body portions 101a and 101c can be prevented from being worn, and the durability is improved. In particular, according to the configurations of claims 5 and 6, since the auxiliary ring portions 101b and 101d act so as to press against the wall surface of the axle case 78, the intrusion of foreign matter and muddy water and the overflow of grease are prevented while simplifying the configuration.

It is a side view of a tractor. It is a diagram which shows the transmission mechanism of the transmission of a tractor. It is a plane sectional view showing a rear axle transmission configuration. It is sectional drawing of an example which shows a brake operating shaft and its periphery structure. It is a disassembled perspective view of a brake mechanism and a brake operation shaft part. It is sectional drawing of another example which shows a brake operating shaft and its periphery structure. It is sectional drawing of another example which shows a brake operation shaft and its periphery structure. It is sectional drawing of another example which shows a brake operation shaft and its periphery structure. It is sectional drawing of another example which shows a brake operation shaft and its periphery structure. They are a rear view (A), a left side view (B), and a right side view (C) of the brake pedal and its peripheral configuration. It is the rear view (A) of a brake pedal part, and its side view (B).

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

  A tractor 1 as a work vehicle of the present embodiment shown in FIG. 1 is a work vehicle such as an agricultural tractor that performs work on a farm field or the like while self-propelled by power generated by a power source. The tractor 1 includes a front wheel 2, a rear wheel 3, an engine 4 as a power source, and a transmission (transmission) 5. Among these, the front wheel 2 is mainly provided as a steering wheel, that is, a steering wheel. The rear wheel 3 is mainly provided as a driving wheel, that is, a driving wheel. Rotational power generated by the engine 4 mounted in the bonnet 6 at the front of the machine body can be transmitted to the rear wheel 3 by appropriately decelerating it with a transmission 5 (transmission). A driving force is generated by the rotational power. In addition, the transmission 5 can transmit the rotational power generated by the engine 4 to the front wheels 2 as necessary. In this case, the four wheels of the front wheels 2 and the rear wheels 3 serve as driving wheels. Generate driving force. That is, the transmission 5 can switch between two-wheel drive and four-wheel drive, and can reduce the rotational power of the engine 4 and transmit the reduced rotational power to the front wheels 2 and the rear wheels 3. Further, the tractor 1 is provided with a connecting device 7 to which a working machine such as a rotary (not shown) can be mounted at the rear of the machine body.

  The tractor 1 has a steering handle 11 erected from a dashboard 10 on the front side of the cockpit 8 and various operation pedals such as a clutch pedal, a brake pedal, and an accelerator pedal, a forward / reverse lever, a shift lever, etc. Various operation levers are arranged.

  FIG. 2 is a diagram showing the transmission mechanism 13 as the transmission 5 in the transmission case 12. The transmission 5 includes a transmission case 12 (see FIG. 1) and a transmission mechanism 13 that is disposed in the transmission case 12 and transmits rotational power from the engine 4 to the rear wheels 3 and the like. The transmission mechanism 13 transmits the rotational power from the engine 4 to the front wheels 2, the rear wheels 3, and the work equipment attached to the machine body, and drives them with the rotational power from the engine 4.

  Specifically, the transmission mechanism 13 includes an input shaft 14, a forward / reverse switching mechanism 15, a Hi-Lo transmission mechanism 16, a main transmission mechanism 17, an auxiliary transmission mechanism 18, a 2WD / 4WD switching mechanism 19, and a PTO. (Power take-off) It is comprised including the drive mechanism 20 grade | etc.,. The transmission mechanism 13 transmits the rotational power generated by the engine 4 to the rear wheel 3 through the input shaft 14, the forward / reverse switching mechanism 15, the Hi-Lo transmission mechanism 16, the main transmission mechanism 17, and the auxiliary transmission mechanism 18 in order. be able to. In addition, the transmission mechanism 13 transmits the rotational power generated by the engine 4 to the input shaft 14, the forward / reverse switching mechanism 15, the Hi-Lo transmission mechanism 16, the main transmission mechanism 17, the auxiliary transmission mechanism 18, and the 2WD / 4WD switching mechanism 19. It can be transmitted to the front wheel 2 via the order. Further, the transmission mechanism 13 can transmit the rotational power generated by the engine 4 to the work machine via the input shaft 14 and the PTO drive mechanism 20 in this order.

  The input shaft 14 is coupled to the output shaft of the engine 4 and receives rotational power from the engine 4.

  The forward / reverse switching mechanism 15 can switch the rotational power transmitted from the engine 4 to forward rotation or backward rotation. The forward / reverse switching mechanism 15 includes a forward gear stage 15a, a reverse gear stage 15b, a reverse counter gear 15c, a forward hydraulic multi-plate clutch C1 in the form of a hydraulic multi-plate clutch, and a reverse hydraulic multi-plate clutch C2. The forward / reverse hydraulic multi-plate clutches C1, C2 can switch the power transmission path in the forward / reverse switching mechanism 15 by switching the engaged / released state. The forward / reverse switching mechanism 15 transmits the rotational power transmitted to the input shaft 14 according to the engaged / released state of the forward / reverse hydraulic multi-plate clutches C1 and C2 to the counter shaft 21 by changing the transmission path.

  When the forward hydraulic multi-plate clutch C1 is in the engaged state and the reverse hydraulic multi-plate clutch C2 is in the released state, the forward / reverse switching mechanism 15 converts the rotational power transmitted to the input shaft 14 to the forward gear 15a, forward It is transmitted to the countershaft 21 by forward rotation through the hydraulic multi-plate clutch C1. When the forward hydraulic multi-plate clutch C1 is in the released state and the reverse hydraulic multi-plate clutch C2 is in the engaged state, the forward / reverse switching mechanism 15 transmits the rotational power transmitted to the input shaft 14 to the reverse side gear stage 15b and the reverse gear. 15c, transmitted to the countershaft 21 by reverse rotation through the reverse hydraulic multi-plate clutch C2. Thereby, the forward / reverse switching mechanism 15 can switch the forward / backward movement of the tractor 1.

  The forward / reverse switching mechanism 15 also functions as a main clutch. When both the forward / reverse hydraulic multi-plate clutches C1 and C2 are released, a neutral state is established, and power is transmitted to the front wheels 2 and the rear wheels 3 side. Can be cut off. The forward / reverse switching mechanism 15 can switch between forward, reverse, and neutral by hydraulic control by operating an unillustrated forward / reverse switching lever by an operator, for example. Further, by depressing the clutch pedal, both the forward and reverse hydraulic multi-plate clutches C1 and C2 can be released.

  The Hi-Lo speed change mechanism 16 can change the rotational power transmitted from the engine 4 at a high speed stage or a low speed stage. The Hi-Lo transmission mechanism 16 includes a Hi (high speed) side gear stage 16a, a Lo (low speed) side gear stage 16b, a hydraulic multi-plate clutch (Hi (high speed) side clutch) C3, and a hydraulic multi-plate clutch (Lo (low speed) side). Clutch) C4. The hydraulic multi-plate clutches C3 and C4 can switch the power transmission path in the Hi-Lo transmission mechanism 16 by switching the engaged / released state. The Hi-Lo transmission mechanism 16 transmits the rotational power transmitted to the counter shaft 21 to the transmission shaft 22 by changing the transmission path in accordance with the engaged / released state of the hydraulic multi-plate clutches C3 and C4. When the hydraulic multi-plate clutch C3 is in the engaged state and the hydraulic multi-plate clutch C4 is in the released state, the Hi-Lo transmission mechanism 16 transmits the rotational power transmitted to the counter shaft 21 to the hydraulic multi-plate clutch C3, Hi side. The speed is changed via the gear stage 16a and transmitted to the transmission shaft 22.

  The Hi-Lo transmission mechanism 16 transmits the rotational power transmitted to the counter shaft 21 to the hydraulic multi-plate clutch C4, Lo side when the hydraulic multi-plate clutch C3 is in the released state and the hydraulic multi-plate clutch C4 is in the engaged state. The speed is changed via the gear stage 16 b and transmitted to the transmission shaft 22. As a result, the Hi-Lo transmission mechanism 16 can change the rotational power from the engine 4 at the transmission ratio of the Hi side gear stage 16a or the transmission ratio of the Lo (low speed) side gear stage 16b and transmit it to the subsequent stage. it can. The Hi-Lo speed change mechanism 16 switches between the Hi (high speed) side and the Lo (low speed) side by hydraulic control when an unillustrated Hi-Lo changeover switch (high / low speed change operation switch) is turned on / off by an operator, for example. The speed can be changed in one of two stages of high speed and low speed. Further, the Hi-Lo speed change mechanism 16 can change speed while the tractor 1 is traveling due to the above-described configuration.

The main speed change mechanism 17 can change the rotational power transmitted from the engine 4 at any one of a plurality of shift speeds. The main speed change mechanism 17 is a synchromesh type speed change mechanism, and here, the rotational power transmitted from the engine 4 via the forward / reverse switching mechanism 15 and the Hi-Lo speed change mechanism 16 can be changed. The main transmission mechanism 17 includes a first gear 17a as a plurality of gears.
The second speed gear stage 17b, the third speed gear stage 17c, the fourth speed gear stage 17d, the fifth speed gear stage 17e, and the sixth speed gear stage 17f are included. The main transmission mechanism 17 transmits the rotational power transmitted to the transmission shaft 22 according to the coupling state of the first speed gear stage 17a to the sixth speed gear stage 17f with the transmission shaft 22 from the first speed gear stage 17a to the first speed gear stage 17a. The speed is changed via one of the sixth speed gears 17f and transmitted to the transmission shaft 23. Thus, the main transmission mechanism 17 can shift the rotational power from the engine 4 at any gear ratio of the first speed gear stage 17a to the sixth speed gear stage 17f and transmit it to the subsequent stage. The main transmission mechanism 17 can select and switch one of a plurality of shift stages by operating a main shift operation lever (not shown) by an operator, for example. The speed can be changed at any one of the six speeds of the sixth speed gear stage 17f. Further, the main transmission mechanism 17 can change gears while the tractor 1 is traveling due to the above-described configuration.

  The auxiliary transmission mechanism 18 can change the rotational power transmitted from the engine 4 through the forward / reverse switching mechanism 15, the Hi-Lo transmission mechanism 16, and the main transmission mechanism 17 in order. The sub-transmission mechanism 18 includes a first sub-transmission 24, a second sub-transmission 25, and the like, and the rotational power transmitted to the transmission shaft 23 is transmitted to the first sub-transmission 24 and the second sub-transmission 25. And the like, and then transmitted to the transmission shaft 26. The first sub-transmission 24 can transmit the rotational power transmitted from the engine 4 and shifted by the main transmission mechanism 17 or the like at the high speed stage or the low speed stage and transmit it to the rear wheel 3 side that is the driving wheel. The second sub-transmission 25 shifts the rotational power transmitted from the engine 4 and shifted by the main transmission mechanism 17 or the like at an ultra-low speed lower than that of the first sub-transmission 24, and the rear wheel 3 is a driving wheel. Can be transmitted to the side. The second auxiliary transmission 25 is omitted when simplification of specifications is required.

  The first sub transmission 24 of the sub transmission mechanism 18 includes a first gear 24a, a second gear 24b, a third gear 24c, a fourth gear 24d, and a shifter 24e. The first gear 24a is coupled to the transmission shaft 23 so as to be integrally rotatable, and rotational power from the transmission shaft 23 is transmitted (input). The second gear 24b meshes with the first gear 24a. The third gear 24c is coupled to the second gear 24b so as to be integrally rotatable. The fourth gear 24d meshes with the third gear 24c. The shifter 24e switches the coupling state of the first gear 24a, the fourth gear 24d, and the transmission shaft 26. That is, a clutch pawl 26a provided integrally with the transmission shaft 26, a clutch pawl 24ac integral with the first gear 24a, and a clutch pawl 24dc integral with the fourth gear 24d are formed with the same diameter and the same number of teeth in an adjacent state. Power is transmitted from the first gear 2a to the transmission shaft 26 when the clutch pawl 26a and the clutch pawl 24ac are simultaneously engaged, and when the clutch pawl 26a and the clutch pawl 24dc are simultaneously engaged, In this configuration, power is transmitted to the transmission shaft 26. Each clutch pawl is arranged and configured to be shiftable to a position where the shifter 24e does not engage with either the clutch pawl 24ac or the clutch pawl 24dc.

  The shifter 24e has a Hi (high speed) side position where the first gear 24a and the transmission shaft 26 are coupled so as to be integrally rotatable, a Lo (low speed) side position where the fourth gear 24d and the transmission shaft 26 are coupled so as to be integrally rotatable, Neither the first gear 24a nor the fourth gear 24d is coupled to the transmission shaft 26 and can move to the neutral position (neutral position) to be released. The first sub-transmission 24 transmits the rotational power transmitted to the transmission shaft 23 to the transmission shaft 26 by switching the transmission path according to the position of the shifter 24e.

  The second subtransmission 25 of the subtransmission mechanism 18 includes a first gear 25a, a second gear 25b, a third gear 25c, a fourth gear 25d, and a shifter 25e. The first gear 25a is coupled to the fourth gear 24d of the first auxiliary transmission 24 so as to be integrally rotatable. The second gear 25b meshes with the first gear 25a. The third gear 25c is coupled to the second gear 25b so as to be integrally rotatable. The fourth gear 25d meshes with the third gear 25c. The shifter 25e switches the coupling state between the fourth gear 25d and the transmission shaft 26. That is, a clutch pawl 26b provided integrally with the transmission shaft 26 and a clutch pawl 25dc integral with the fourth gear 25d are formed in the same diameter and the same number of teeth and are arranged adjacent to each other, and the shifter 25e is disposed adjacent to the clutch pawl 26b. When the clutch pawls 25dc are simultaneously engaged, power is transmitted from the fourth gear 25d to the transmission shaft 26.

  The shifter 25e has an ultra-low (ultra-low speed) side position where the fourth gear 25d and the transmission shaft 26 are coupled so as to be integrally rotatable, and a neutral position (neutral position) where the fourth gear 25d and the transmission shaft 26 are not coupled and released. Position). In this case, the rotation of the transmission shaft 26 is governed by the position of the shifter 24 e of the first auxiliary transmission 24. The second sub-transmission 25 transmits the rotational power transmitted to the transmission shaft 23 to the transmission shaft 26 by switching the transmission path according to the position of the shifter 25e. When the first sub-transmission 24 is in the neutral state and the shifter 25e is in the super-Lo position, the second sub-transmission 25 uses the rotational power transmitted to the transmission shaft 23 as the first sub-transmission 24. From the first gear 24a, the second gear 24b, the third gear 24c, the fourth gear 24d, the first gear 25a, the second gear 25b, the third gear 25c, the fourth gear 25d, and the shifter 25e of the second auxiliary transmission 25 are connected. Are sequentially decelerated through and transmitted to the transmission shaft 26. As a result, the second auxiliary transmission 25 converts the rotational power from the engine 4 into the second gear 24b, the third gear 24c, the fourth gear 24d, the first gear 25a, the second gear 25b, the third gear 25c, The speed can be changed at a speed ratio on the super-Lo (super-low speed) side via the four gears 25d and transmitted to the subsequent stage. Further, when the shifter 25e is in the neutral position, the second auxiliary transmission 25 is in a state where the fourth gear 25d is idling with respect to the transmission shaft 26, that is, in a neutral state.

  Therefore, the subtransmission mechanism 18 combines the rotational power transmitted to the transmission shaft 23 with the first subtransmission 24 and the second subtransmission 25, so that of the three stages of high speed, low speed, and ultra-low speed. Either can be changed and transmitted to the transmission shaft 26.

  Then, the transmission mechanism 13 of the transmission 5 transmits the rotational power transmitted to the transmission shaft 26 to the rear wheel 3 via a rear wheel differential 72, a rear axle 77, a planetary gear reduction mechanism 75 for reduction, which will be described later. To do. As a result, in the tractor 1, the rear wheel 3 is rotationally driven as a drive wheel by the rotational power from the engine 4.

  The 2WD / 4WD switching mechanism 19 includes hydraulic multi-plate clutches C6 and C7, and also functions as a front wheel speed increasing mechanism. The 2WD / 4WD switching mechanism 19 includes a transmission shaft 19a, a Hi (high speed) side gear stage 19b, a Lo (low speed) side gear stage 19c, a hydraulic multi-plate clutch (Lo (low speed) side clutch) C6, a hydraulic multi-plate clutch (Hi). (High speed) side clutch) C7 and transmission shaft 19d are included. The hydraulic multi-plate clutches C6 and C7 can switch the power transmission path in the 2WD / 4WD switching mechanism 19 by switching the engaged / released state. The 2WD / 4WD switching mechanism 19 transmits the rotational power transmitted to the transmission shaft 19a to the transmission shaft 19d by changing the transmission path according to the engaged / released state of the hydraulic multi-plate clutches C6 and C7. When the hydraulic multi-plate clutch C6 is in the engaged state and the hydraulic multi-plate clutch C7 is in the released state, the 2WD / 4WD switching mechanism 19 transmits the rotational power transmitted to the transmission shaft 19a to the Lo-side gear stage 19c, The speed is changed via the plate clutch C6 and transmitted to the transmission shaft 19d.

  The 2WD / 4WD switching mechanism 19 switches whether or not the rotational power transmitted to the transmission shaft 26 is transmitted to the front wheel 2 side. The 2WD / 4WD switching mechanism 19 includes a transmission shaft 19a, a Hi-side gear stage 19b, a Lo-side gear stage 19c, a transmission shaft 19d, and a shifter 19e. The transmission shaft 19a transmits (inputs) the rotational power from the transmission shaft 26 via the gear 30, the gear 31, the transmission shaft 32, the coupling 33, and the like. The transmission gear 19a is inserted into the first gear 19b, and the first gear 19b is assembled so as to be rotatable relative to the transmission shaft 19a.

The transmission mechanism 13 of the transmission 5 transmits the rotational power transmitted to the transmission shaft 19d to the front wheels 2 via the front wheel differential 34, the front axle 35, the vertical axis 36, the planetary gear reduction mechanism 37, and the like. As a result, the tractor 1 can be driven by four-wheel drive, with the front wheels 2 and the rear wheels 3 being rotationally driven as drive wheels by the rotational power from the engine 4. In the 2WD / 4WD switching mechanism 19, the transmission of the rotational power transmitted to the transmission shaft 19a to the transmission shaft 19d side is interrupted by the hydraulic multi-plate clutches C6 and C7 being both released. As a result, the tractor 1 can travel by two-wheel drive.

  The PTO drive mechanism 20 drives the work machine with the power from the engine 4 by shifting the rotational power transmitted from the engine 4 and outputting it to the work machine from the PTO shaft 40 (see FIG. 2) at the rear of the machine body. It is. The PTO drive mechanism 20 includes a PTO clutch mechanism 38, a PTO transmission mechanism 39, a PTO shaft 40, and the like.

  The PTO clutch mechanism 38 switches between transmission and interruption of power to the PTO shaft 40 side. The PTO clutch mechanism 38 includes a gear 38a, a hydraulic multi-plate clutch C5, and a transmission shaft 38b. The gear 38a meshes with a gear 41 that is coupled to the input shaft 14 so as to be integrally rotatable. The hydraulic multi-plate clutch C5 switches the power transmission state between the gear 38a and the transmission shaft 38b by switching the engaged / released state. The PTO clutch mechanism 38 enters a PTO drive state in which power is transmitted to the PTO shaft 40 side when the hydraulic multi-plate clutch C5 is engaged, and the rotational power transmitted from the input shaft 14 to the gear 38a via the gear 41. Is transmitted to the transmission shaft 38b via the hydraulic multi-plate clutch C5. When the hydraulic multi-plate clutch C5 is released, the PTO clutch mechanism 38 is in a PTO non-driven state (neutral state) in which transmission of power to the PTO shaft 40 side is interrupted, and the rotational power transmitted to the gear 38a is reduced. Transmission to the transmission shaft 38b side is interrupted.

  The tractor 1 is provided with a gear pump 70 through a gear 70a meshing with the gear 38a, a gear 70b meshing with the gear 70a, and the like. The gear pump 70 applies hydraulic pressure to a hydraulic system such as the transmission mechanism 13.

  The PTO speed change mechanism 39 changes speed when power is transmitted to the PTO shaft 40 side. The PTO transmission mechanism 39 includes a Hi (high speed) side gear stage 39a, a Lo (low speed) side gear stage 39b, a transmission shaft 39c, and a shifter 39d. The PTO transmission mechanism 39 changes the rotational power transmitted to the transmission shaft 38b via the Hi side gear stage 39a or the Lo side gear stage 39b according to the position of the shifter 39d, and transmits it to the transmission shaft 39c. To do.

  The PTO shaft 40 is coupled to a work machine side input shaft (not shown) via a universal joint shaft (not shown), and transmits rotational power from the engine 4 to the work machine. Since the transmission shaft 39c is offset from the center of the machine body, the PTO shaft 40 is disposed at the center of the machine body so that it can be transmitted via the first gear 44, the second gear 45, and the like.

  The transmission shaft 26 supported by the rear mission case 12R has a drive pinion portion 71 formed at the rear end thereof engaged with a ring gear 72a of the rear wheel differential mechanism 72. The rear wheel differential mechanism 72 has a known configuration in which a small pinion and a bevel gear meshing with the small pinion are combined in the differential case 72b, and can transmit the rotation of the ring gear 72a to the left and right differential output shafts 73L and 73R. The left and right axles 73L and 73R constitute multi-plate brake mechanisms 74L and 74R. Furthermore, on the lower transmission side of the brake mechanisms 74L and 74R, planetary gear transmission type reduction mechanisms 75L and 75R are provided. The rotation of the output carriers 76L and 76R of the speed reduction mechanisms 75L and 75R is transmitted to the left and right rear axles 77L and 77R provided coaxially with the differential output shafts 73L and 73R. The left and right rear axles 77L and 77R are provided with wheel mounting flanges 77a and 77a, respectively.

  The rear axle cases 78L and 78R that support the rear axles 77L and 77R are flange-joined to the side surface of the rear mission case 12R and fastened by a plurality of bolts 79, 79.

  Here, the differential case 72b is supported by the support metals 81L and 81R in the openings 80L and 80R opened on the left and right side surfaces on the rear axle housing 12R side. The support metals 81L and 81R are joined to the support walls 82L and 82R forming the peripheral portions of the openings 80L and 80R of the mission case 12R from the outside, and are bolts 83, 83.

  Press fixing bodies 84L and 84R of the multi-plate brake plate 74a of the brake mechanisms 74L and 74R are fitted on the large diameter base portions of the rear axle cases 78L and 78R. The support walls 82L and 82R for supporting the support metals 81L and 81R are formed inside the case 12R with respect to the outer wall surface of the rear mission case 12R. In the recessed spaces 85L and 85R formed as a result, the support walls 82L and 82R are formed. A brake cam mechanism 74b for pressing the multi-plate brake plate 74a is interposed between the stepped portion formed on the outer surface of the metal 81L, 81R and the multi-plate brake plate 74a. That is, the brake mechanisms 74L and 74R are arranged from the rear mission case 12R to the rear axle cases 78L and 78R.

  On the large diameter base side of the rear axle cases 78L and 78R, a multi-plate brake plate 74a and pressing bodies 84L and 84R are arranged, and further, the speed reduction mechanisms 75L and 75R are arranged. That is, the speed reduction mechanisms 75L and 75R include ring gears 86L and 86R, three planetary gears 87L and 87R, and the output carriers 76L and 76R. The output carriers 76L and 76R support the planetary gears 87L and 87R, and the planetary gears. By simultaneously engaging the gears 87L and 87R with the sun gears 88L and 88R formed at the ends of the differential output shafts 73L and 73R and the ring gears 86L and 86R, the rotation of the differential output shafts 73L and 73R is decelerated and the output carrier 76L , 76R.

  The rear axle cases 78L and 78R are formed so as to extend from the large diameter side A toward the small diameter side C through the conical portion B gradually decreasing in diameter toward the left and right outwards, and the ring gears 86L and 86R are formed on the large diameter side A. Positioned in contact with a step formed near the boundary of the conical portion B through the opening, the pressing fixing bodies 84L and 84R of the multi-plate brake plate 74a have the same diameter as the outer diameter of the ring gears 86L and 86R. Similarly, the ring gears 86L and 86R are inserted through the opening on the large-diameter side A, and are sandwiched between stepped portions formed near the boundary of the conical portion B between the pressing fixing bodies 84L and 84R and the rear axle cases 78L and 78R. It is the structure fixed by 89,89 ....

  Here, the first knock pins 90L and 90R and the second knock pins 91L and 91R are inserted into a plurality of circumferential positions (for example, two locations) of the ring gears 86L and 86R. Among these, the first knock pins 90L and 90R are disposed between the ring gears 86L and 86R and the pressing bodies 84L and 84R, and the second knock pins 91L and 91R are disposed between the rear axle cases 78L and 78R and the ring gears 86L and 86R. . Therefore, the knock pin holes 92L and 92R are formed by drilling in parallel to the axle from the outer surface side at locations corresponding to the step portions reaching the conical portions B of the rear axle cases 78L and 78R, and the ring gears 86L and 86R and the pressing body. The through holes 93L and 93R are formed on the ring gears 86L and 86R side, though the through holes having the same phase are processed and formed in both 84L and 84R.

  With this configuration, the first knock pins 90L, 90R and the second knock pins 91L, 91R are first inserted into the knock pin holes 92L, 92R of the rear axle cases 78L, 78R through the first knock pins 90L, 90R and the ring gears 86L, 86R. The pressing bodies 84L and 84R are positioned, and then the rear knock cases 78L and 78R and the ring gears 86L and 86R can be positioned by inserting the second knock pins 91L and 91R into the same knock pin holes 92L and 92R.

  Brake operating shafts 94L and 94R are provided on the large diameter side A of the rear axle cases 78L and 78R, and the brake cam mechanism 74b is expanded in accordance with the pulling operation of the external brake arms 95L and 95R.

  A differential lock mechanism 96 is incorporated on one side (left side in the illustrated example) of the differential output shafts 73L and 73R. A differential lock clutch 96a is provided on one differential output shaft 73L in a splined manner so as to be slidable in the axial direction, and the differential case 72b is connected to the differential output shaft 73L in an integrated state by a shift interlock operation outside the figure, so that the left and right differential output shafts are integrated. A so-called differential lock can be realized in which 73L and 73R are in the same rotational state.

  The support structure of the output carriers 76L and 76R of the speed reduction mechanisms 75L and 75R is performed by spline fitting the boss portions to the rear axles 77L and 77R. Accordingly, the rotation of the output carriers 76L and 76R is transmitted to the rear axles 77L and 77R. The connection structure of the output carriers 76L and 76R to the rear axles 77L and 77R is positioned and supported by the conical portion B of the rear axle cases 78L and 78R.

  A lubricating configuration of the brake operating shafts 94L and 94R will be described with reference to FIGS. The left side and the right side have a common configuration, and the following description will be made by omitting the symbols L and R. The detailed configuration of the brake operating shaft 94 is supported by a rear axle case 78 at an intermediate portion thereof, and an engagement arm that engages a brake cam mechanism 74b on the inner end side of the brake operating shaft 94 that passes through the axle case 78. 100 is spline-fitted. The brake cam mechanism 74b is composed of a rotation plate 74bR, a fixed plate 74bT facing the rotation plate 74bT, a steel ball 74bB provided between them, and the like, and when the engagement arm 100 is rotated at an appropriate angle in a predetermined direction, The engaging steel ball 74bB gradually shifts to the shallower side in the cam groove formed in the rotating plate 74bR by engaging and rotating a recess formed in a protruding part on the rotating plate 74bR side, At this time, since the fixed plate 74bT is fixed to the rear axle case 78, the rotating plate 74bR is moved in the axial direction of the axle 73 to apply thrust to the plurality of brake plates 74b, 74b. Thus, the axle 73 can be braked.

  A brake arm 95 is spline-fitted or serrated fitted to the outer end side of the rear axle case 78 of the brake operating shaft 94. A gap S exists between the boss 95a of the brake arm 95 and the rear axle case 78, and the collar 101 is mounted so as to fill the gap S. An integrated configuration such as a spline is not employed between the collar 101 and the brake operating shaft 94. A through hole 102 is formed in the outer periphery of the collar 101, and a grease nipple 103 is screwed into the through hole 102. The rear axle case 78 side of the collar 101 is in contact with or in close proximity to the case wall surface, and the inner diameter of the collar 101 is set so as to form a gap L for grease filling or transition on the inner peripheral surface. Reference numeral 104 denotes a seal.

  When grease is injected from the grease nipple 103, the inner periphery of the collar 101 is reached, and the inlet of the brake operating shaft 94 support hole 78H of the rear axle case 78 can be closed by filling the grease. For this reason, infiltration of muddy water or the like into the rear axle case 78 can be prevented. In addition, by providing the collar 101 itself and bringing the rear axle case 78 side of the collar 101 into contact with the case wall surface, it is possible to prevent foreign matter from colliding with the brake operating shaft 94 and to prevent direct intrusion of muddy water. Prevent and eliminate most.

  FIG. 7 shows an improved structure. That is, shims 105, 105... Are appropriately interposed between the collar 101 and the boss portion 95a of the brake arm 95. With this configuration, the collar 101 is always subjected to contact pressure on the rear axle case 78 side, and can effectively prevent muddy water from entering the through hole 102.

  FIGS. 8 to 10 show further improved structures. In each case, in order to prevent wear due to contact between the collar 101 and the rear axle case 78 formed by casting, an O-ring is used for the collar main body portion and the auxiliary ring portion for preventing wear. Intervene. In the example of FIG. 8, the auxiliary ring portion 101b is fitted to the outer periphery of the collar main body portion 101a, and the O-ring 106 is provided therebetween. With this configuration, the collar main body 101a forms a gap with the end surface of the rear axle case 78, and the end surface of the auxiliary ring portion 101b can be set so as to contact the rear axle case 78. The portion 101b prevents intrusion of foreign matter and muddy water and overflow of filled grease, and prevents the above-described wear without the collar main body portion 101a coming into contact with the rear axle case 78. The fitting groove into which the O-ring 106 is fitted is formed in the outer peripheral portion of the collar main body portion 101a and / or the inner peripheral portion of the auxiliary ring portion 101b.

  As shown in FIG. 9, the outer shape of the collar main body portion 101a is made different and the auxiliary ring portion 101b is fitted to the smaller diameter side, and the stepped wall portion between the large diameter and the small diameter of the collar main body portion 101a and the auxiliary ring portion 101b. .. Are interposed between the auxiliary ring portion 101b and the rear axle case 78, and the effect of preventing the intrusion of foreign matter and muddy water and preventing the overflow of grease is enhanced. In addition, the worn auxiliary | assistant ring part 101b can be replaced | exchanged easily.

  Further, in the configuration shown in FIG. 10, the collar 101 is constituted by the collar main body portion 101c and the auxiliary ring portion 101d, and the fitting groove for holding the O-ring 108 formed in the collar main body portion 101c is opposed to the rear axle case 78. The auxiliary ring portion 101d is disposed between the collar main body portion 101c and the wall surface of the end portion of the rear axle case 78. Since the auxiliary ring portion 101d is pressed against the opposing end face of the rear axle case 78 by the elasticity of the O-ring 108, it is possible to satisfactorily prevent entry of foreign matter and muddy water and overflow of grease while simplifying the configuration.

  Next, the brake pedal for braking the brake arm 95 will be described. Left and right brake pedals 110L and 110R are suspended from the upper horizontal shaft 111 on the right side of the floor of the cockpit 8 so as to be interlocked with each stepping operation. By connecting one end of the linkage rods 112L and 112R and connecting the other ends to the brake arms 95L and 95R, the left and right brake mechanisms 74L and 74R can be configured to be braked separately on the left and right.

  The left and right brake pedals 110L and 110R bosses are fitted to the horizontal shaft 111, the left brake pedal 110L and the horizontal shaft 111 are integrated by appropriate means, and a bracket is attached to the left end of the horizontal shaft 111. One end of the left linkage rod 112L is connected through the via. Further, one end of the right linkage rod 112R is connected to the boss portion of the right brake pedal 110R loosely fitted to the horizontal shaft 111 via a bracket.

  The left and right brake pedals 110L and 110R can be stepped independently on the left and right sides, and as described above, the left and right brake mechanisms 74L and 74R can be braked independently. However, the pedal lock mechanism 113 includes the pedal lock mechanism. When the left and right brake pedals 110L and 110R are connected to each other by 113, both the left and right brake pedals 110L and 110R can be operated to brake both the left and right brake mechanisms 74L and 74R. If you do, you can ensure safety. The pedal lock mechanism 113 includes a lock plate 113a that is swingably provided on the arm portion of the left and right brake pedal 110L via a bracket, and a lock plate receiver 113b that is provided on the left and right brake pedal 110R. The left and right brake mechanisms 74L and 74R can be braked independently or simultaneously in conjunction with the left and right by rotating the lock plate 113a around the supporting fulcrum and connecting and disconnecting the brake pedals 110L and 110R. It can be carried out.

  When the left and right brake pedals 110L and 110R are depressed, a brake lamp (not shown) provided at the rear of the vehicle body is lit. This brake lamp switch 114 corresponds to one brake pedal (right side in the example) 110R. It is provided at the position where The switch 114 is switched to ON or OFF when the operating portion 114a protrudes from the front surface and pushes in the operating portion 114a. When the switch 114 is released from the pushing, the operating portion 114a returns to reverse. Or switch to ON. Conventionally, the actuating part 114a of the switch 114 is configured to be pressed by the back of the arm part of the brake pedal 110R. However, the actuating part 114a and the back of the arm part may be displaced from the opposing relationship due to an assembly error. There is a possibility that brake information cannot be performed. Therefore, the switch operation plate 115 is attached to the brake pedal 110R facing the brake lamp switch 114, and the substantial switch action surface is enlarged so as to be able to cope with the right and left positional deviation due to the above-described assembly error. Is. The actuating plate 115 fixes an appropriately shaped sheet metal material near the boss portion of the corresponding brake pedal 110R by welding or the like.

  For example, a locking plate 116b formed with a plurality of locking claws 116a, 116a,... In an arc shape is fixed to the arm portion of the left brake pedal 110L, and an engagement plate that can be rotated about the horizontal axis on the machine body side. The lever 116d provided with 116c is provided, and the parking brake mechanism 116 is comprised by these.

74 Brake mechanism 78 Rear axle case (axle case)
94 Brake operating shaft 95 Brake arm 95a Boss portion 101 Color 101a Color main body portion 101b Auxiliary ring portion 101c Color main body portion 101d Auxiliary ring portion 102 Through hole 103 Grease nipple 105 Shim 106 O-ring 107 Shim 108 O-ring

Claims (6)

  A brake operating shaft (94) for operating a brake mechanism (74) provided in the axle case (78) is rotatably provided through the axle case (78), and the brake operation is performed outside the axle case (78). A brake arm (95) is connected to the shaft (94), and a collar (101) is mounted between the boss portion (95a) of the brake arm (95) and the axle case (78). A through hole (102) is formed in the outer periphery, and a grease nipple (103) is provided in the through hole (102), and the collar (101) is brought into contact with the wall surface of the axle case (78). A work vehicle in which a gap (L) for grease filling or grease transfer is formed on the inner peripheral surface of the collar (101).   The work vehicle according to claim 1, wherein shims (105, 105 ...) are interposed between the collar (101) and a boss portion (95a) of the brake arm (95).   The collar (101) is formed by providing a color main body (101a) and an auxiliary ring (101b) with an O-ring (106) interposed therebetween, and the auxiliary ring (101b) is in contact with the axle case (78). The work vehicle according to claim 1.   The work vehicle according to claim 3, wherein an auxiliary ring portion (101b) is fitted to the outer periphery of the collar main body portion (101a), and an O-ring (106) is provided therebetween.   The collar body (101a) has a different outer diameter, and the auxiliary ring portion (101b) is fitted to the smaller diameter side. The stepped wall portion and the auxiliary ring portion (101b) of the collar body portion (101a) having a large diameter and a small diameter. 5. A work vehicle according to claim 4, wherein shims (107, 107...) Are interposed therebetween.   Of the color main body (101c) and auxiliary ring portion (101d) constituting the collar (101), the auxiliary ring portion (101d) is sandwiched between the color main body portion (101c) and the wall surface of the axle case (78). The work vehicle according to claim 3, wherein the work vehicle is arranged in a shape and an O-ring (108) is interposed between the collar main body portion (101c) and the auxiliary ring portion (101d).

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