JP2013028198A - Working vehicle - Google Patents

Abstract

In a work vehicle in which a shift operation and a parking brake operation are performed by a single operation lever, the parking brake operation is simplified.
A parking brake mechanism 17 capable of regulating the operation of a transmission mechanism TM, an operation member 44 for transmitting an operation of an operation lever 19A to the transmission mechanism TM or the parking brake mechanism 17, and a state in which the operation of the transmission mechanism TM is regulated. And a lock mechanism 18 capable of maintaining the parking brake mechanism 17, a neutral path as a speed change operation path of the operation lever 19 </ b> A, and a speed change path extending linearly from the neutral path, and a brake operation of the operation lever 19 </ b> A As a path, a brake path that extends from the neutral path in a direction that intersects the speed change path and the parking brake mechanism 17 operates, and a lock path that extends from at least the end of the brake path in a direction that intersects the brake path and the lock mechanism 18 operates. , With.
[Selection] Figure 5

Description

  The present invention relates to a work vehicle in which a shift operation and a parking brake operation are performed by a single operation lever.

  Conventionally, as such a work vehicle, for example, as in the technique described in Patent Document 1, a transmission mechanism that is disposed inside a transmission case and transmits a rotational driving force from an engine to a traveling device, and a transmission mechanism. A transmission device (in the literature, “main transmission device”) that can change the vehicle speed by changing the rotational driving force, and a parking brake mechanism that is disposed inside the transmission case and can regulate the operation of the transmission mechanism (In the literature, there is a “parking lock device”) and a tractor including a single operation lever that can be manually operated to swing and that can perform a speed change operation of the transmission and a brake operation of the parking brake mechanism. .

  The tractor is supported by the transmission case in the state extending inside and outside the transmission case, and is connected to the operation lever so as to follow the operation of the operation lever, and is linked to the transmission mechanism and the parking brake mechanism separately. An operation member that transmits the operation of the operation lever to the transmission mechanism or the parking brake mechanism (in the literature, “operation shaft”) and the position of the operation lever or the operation member are restrained to operate the parking brake mechanism and the operation of the transmission mechanism. And a lock mechanism (in the literature, “lever guide” and “engagement portion” which is a lower end portion of the operation lever).

  In the technique described in Patent Document 1, the transmission is a so-called manual transmission, and intersects a neutral neutral path and a linear neutral path corresponding to the neutral state of the transmission as a transmission operation path of the operation lever. A speed change path (shifting to “1st speed”, “2nd speed”, “3rd speed”, “R (back)”) corresponding to the speed change state of the transmission and extending linearly from the neutral path with respect to the direction I have.

  And in the technique of patent document 1, after extending a neutral path | route from the range which provided the speed change path | route, with respect to the direction (direction parallel to a speed change path | route) which cross | intersects a neutral path | route from the terminal end of a neutral path | route. A brake operation path extending linearly is provided. By operating the operation lever along this brake operation path, the operation member rotates, the parking brake mechanism swings, and the parking brake is applied. That is, it is possible to make the driver aware that the parking brake operation is being performed by an operation in a direction different from the neutral route.

  Furthermore, a lock path for operating the lock mechanism is provided at the end of the brake path, and the operation lever cannot be operated from the lock path to the neutral path side (brake path) unless the operation lever is pushed down. This prevents the operating lever from coming off the brake path and the parking brake being released unexpectedly.

Japanese Patent No. 3979706 (paragraphs [0007] to [0019], paragraphs [0033] to [0038], FIGS. 7 to 17)

  However, as described above, the tractor described in Patent Document 1 configures the positional relationship of the parking brake route with respect to the neutral route in the same manner as the positional relationship of the speed change route with respect to the neutral route, thereby allowing the driver to perform the parking brake operation. It makes you aware that you are doing. Therefore, in order to perform the parking brake operation, it is necessary to perform two actions, that is, a route that extends the neutral route and a brake route that intersects the route, and until the operation along the final lock route. Considering this, there are many operation actions, and the driver may feel troublesome.

  In view of such circumstances, an object of the present invention is to simplify a parking brake operation in a work vehicle in which a shift operation and a parking brake operation are performed by a single operation lever.

  A first characteristic configuration of a work vehicle according to the present invention includes a transmission mechanism that is disposed inside a transmission case and transmits a rotational driving force from an engine to a traveling device, and is disposed in the transmission mechanism, and the rotational driving force A transmission that can change the speed of the vehicle by changing the speed of the vehicle, a parking brake mechanism that is disposed inside the transmission case and that can regulate the operation of the transmission mechanism, and can be manually operated to swing. One operating lever capable of gear shifting operation of the device and brake operation of the parking brake mechanism, and supported by the mission case in a state extending inside and outside the mission case, and operated following the operation of the operating lever. Connected to the operating lever, and linked separately to the transmission mechanism and the parking brake mechanism, and the operation of the operating lever is controlled by the transmission mechanism or the parking brake. An operation member that transmits to a brake mechanism, and a lock mechanism that restrains the position of the operation lever or the operation member to maintain the parking brake mechanism in a state in which the operation of the transmission mechanism is restricted, The operation lever includes: a neutral path corresponding to a neutral state of the transmission; and a transmission path linearly extending from the neutral path and corresponding to the transmission state of the transmission. As a brake operation path, the brake path extends from the neutral path in a direction crossing the speed change path, the brake path for operating the parking brake mechanism, and extends from at least the end of the brake path in a direction crossing the brake path, and the lock And a lock path on which the mechanism operates.

  According to this characteristic configuration, the brake path is configured to extend from the neutral path corresponding to the neutral state of the transmission to the direction intersecting the transmission path. Therefore, when performing the parking brake operation, only the transmission is related. It is only necessary to perform one action of deviating the operation lever from the original neutral route, and thereafter the state can be maintained by the parking brake mechanism. Thus, with this configuration, the parking brake operation is simplified.

  A second characteristic configuration of the work vehicle according to the present invention is that an end portion of the lock path opposite to a terminal end of the brake path is folded back toward the neutral path.

  With this feature configuration, the end of the lock path opposite to the end of the brake path is folded back to the neutral path side. It is necessary to move in the direction opposite to the path, change direction and move toward the end of the brake path, further change direction and move to the neutral path along the brake path. Therefore, the parking brake is not easily released unexpectedly.

  According to a third characteristic configuration of the work vehicle according to the present invention, the transmission can shift the rotational driving force in a plurality of stages, the neutral path is a linear path, and the parking brake mechanism includes the transmission The posture can be changed by swinging between a restricted state that engages with a part of the mechanism and a non-restricted state that does not bite, the brake path is provided on an extension line of the neutral path, and the operation lever is provided on the neutral path or the brake The operation member is configured to slide when operated along a route, and the operation member presses the parking brake mechanism by the sliding movement, so that the parking brake mechanism is changed from the non-restricted state to the restricted state. The point is to change the posture.

  According to this characteristic configuration, in a work vehicle in which the transmission can change the rotational driving force in a plurality of stages and the neutral path is a straight path, a work vehicle having a so-called manual transmission, The route is provided on an extension line of the neutral route, and the operation member is configured to slide when the operation lever is operated along the neutral route or the brake route. Then, as the operating member slides, the parking brake mechanism is pressed and swung to enter a restricted state, and the parking brake is applied. That is, the sliding direction of the operating member coincides with the swinging direction of the parking brake mechanism, and the parking brake operation of the operating lever is linearly transmitted to the parking brake mechanism through the sliding movement of the operating member.

  As a result, it is not necessary to change the direction of the operating force generated by sliding the operating member and transmit it to the parking brake mechanism, and it is possible to operate the parking brake mechanism with a simple configuration without providing an unnecessary link mechanism. It becomes.

  According to a fourth characteristic configuration of the work vehicle according to the present invention, a first urging mechanism that constantly urges the operation lever toward a center side of the neutral path and a first urging mechanism are provided separately from the first urging mechanism. And a second urging mechanism that urges the operation lever toward the neutral path when it is located on the brake path.

  According to this configuration, the first urging mechanism constantly urges the operation lever toward the center of the neutral path, and the second urging mechanism moves the operation lever to the neutral path only when the operation lever is positioned on the brake path. Energize to the side. That is, in particular, when the brake path is provided in a straight line with the neutral path, when the operation lever is operated from the neutral path to the brake path, the biasing force by the second biasing mechanism is added to the biasing force by the first biasing mechanism. The force is applied to the operation lever, and the lever operation becomes heavy. Therefore, the driver can sensuously sense that the operating lever has been operated along the brake path.

  Also, with this configuration, when one of the speed change paths extends from the vicinity of the boundary with the brake path in the neutral path, the reaction force (biasing force) to the lever operation increases easily. The operating lever does not enter the brake path, and the starting end of the speed change path can be understood sensuously, so that the lever can be reliably operated to the speed change path.

  According to a fifth characteristic configuration of the work vehicle according to the present invention, the first urging mechanism is disposed over the transmission case and the operation member, and the second urging mechanism is disposed in the parking brake mechanism. And when the parking brake mechanism is in the restricted state, the operating member and the parking brake mechanism are in contact with each other, and the parking brake mechanism is separated from the parking brake mechanism. When the brake mechanism is in the unregulated state, the operation member and the parking brake mechanism are configured to be separated from each other.

  According to this feature configuration, the first urging mechanism that constantly urges the operation lever toward the center of the neutral path is provided across the transmission case and the operation member, and only when the operation lever is positioned in the brake path. A second biasing mechanism that biases the operation lever toward the neutral path is attached to the parking brake mechanism. That is, the first biasing mechanism is disposed on the operation member that operates both when the operation lever is operated along the neutral path and when operated along the brake path, and the operation lever is disposed along the brake path. A second urging mechanism is disposed in the parking brake mechanism that operates only when operated. When the parking brake mechanism is in the restricted state, the operation member and the parking brake mechanism abut, and when the parking brake mechanism is in the non-restricted state, the operation member and the parking brake mechanism are separated.

  In other words, by configuring as in this characteristic configuration, when the operation lever is positioned on the neutral path and the brake path (always), the urging force of the first urging mechanism acts on the operation lever. The second urging mechanism can be configured such that the urging force of the second urging mechanism acts on the operation lever via the operation member only when the operation lever is positioned in the brake path.

  In addition, for maintenance in the vicinity of the operation mechanism in the transmission mechanism, the operation lever and the operation member may be configured to be detachable together with a part of the wall portion of the transmission case. In such a case, with this configuration, the parking brake mechanism and the operation member can be separated from each other. It can be set as the structure which can be removed from the main body of a case.

  According to a sixth characteristic configuration of the work vehicle according to the present invention, the lock mechanism is stationary with respect to the operation member or the engaging portion connected to the operation lever, and the operation member and the operation lever. A locked portion fixed to a member, and an end portion of the lock path opposite to a terminal end of the brake path is folded back toward the neutral path, and the operation lever is connected to the lock path. It is in the point which is comprised so that the said latching | locking part may be latched to the said to-be-latched part when it is operated by the path | route which turned up.

  If it is this characteristic structure, it can prevent reliably that an operation lever pulls out from a lock path | route unexpectedly by the physical latching of a latching | locking part and a to-be-latched part.

  According to a seventh characteristic configuration of the work vehicle according to the present invention, the locking portion is formed in a hook shape corresponding to the shape of the brake path and the lock path, and the locking portion is provided on the locked portion. An opening that can be inserted is formed, and when the operation lever is operated to the lock path, the locking portion penetrates the locked portion through the opening, and the operation lever further The opening is configured so that the locking portion is locked to the outer peripheral portion of the opening when operated on the folded path of the lock paths.

  With this feature configuration, the locking portion is formed in a hook shape corresponding to the shape of the brake path and the lock path, and an opening is provided in the locked portion, so that the operation lever can be operated and locked. Since the operation of the mechanism is linked, the reliability and accuracy of the operation of the lock mechanism and the durability of the lock mechanism are improved as compared with a complicated link mechanism.

  An eighth characteristic configuration of the work vehicle according to the present invention is that the operation lever is supported by a bracket fixed to the transmission case, and the locked portion is supported by the bracket.

  According to this characteristic configuration, the bracket that supports the operation lever can be used as a member that supports the locked portion, and the number of parts can be reduced. Further, since the operation lever is frequently used and swings, the bracket as a support member inevitably has a high rigidity (high strength). Since the locked portion is supported by the highly rigid bracket, the locked portion is stably supported.

  A ninth characteristic configuration of the work vehicle according to the present invention is that the operation member and the locking portion are connected to a lower end portion of the operation lever.

  By connecting the operating member and the locking part to the same location (lower end of the operating lever) as in this feature configuration, the operation of the brake mechanism and the operation of the lock mechanism are reliably linked, and the operation of the brake mechanism The operation timing of the lock mechanism with respect to is suitable.

  A tenth characteristic configuration of the work vehicle according to the present invention is that a sub-transmission device different from the transmission device is disposed in the transmission mechanism, and the operation lever and the sub-transmission are mounted on a bracket fixed to the transmission case. The auxiliary transmission lever for operating the device is pivotally supported.

  With this feature configuration, the main transmission lever and the auxiliary transmission lever are supported by the bracket, which is the same member, so that the number of parts can be reduced.

It is a right view of the tractor which concerns on this invention. It is a figure which shows the gear train of the transmission mechanism which concerns on this invention. It is a vertical right side view of a transmission mechanism. FIG. 4 is a right side view of a main transmission lever, a cover member, and the like. It is a rear view of a main transmission lever, a cover member, etc. It is a top view of a main transmission lever, a cover member, etc. It is a front view of a parking brake mechanism. It is a top view of a parking brake mechanism. It is a rear view of a parking brake mechanism etc. at the time of a release state. It is a rear view of a parking brake mechanism etc. at the time of a regulation state. It is a vertical rear view of a cover member etc. in the position of an operation axis. It is a figure which shows the operation path (lever guide) of the main speed-change lever. It is a cross-sectional top view which shows the various states of the lock mechanism corresponding to operation of a main gear shift lever, (a) is a state when a main gear shift lever is located in a neutral path | route, (b) is located in the terminal of a brake path | route. (C) shows a state when positioned on the first lock path, and (d) shows a state when positioned on the second lock path. It is a disassembled perspective view of a locking mechanism. It is a figure which shows the gear train around the creep mechanism and auxiliary transmission which concern on another embodiment.

  Hereinafter, an example in which the present invention is applied to a tractor will be described with reference to the drawings.

[Outline of the tractor]
As shown in FIG. 1, the tractor includes an engine E, a clutch housing CH, and a transmission case MC. The engine E and the transmission case MC are connected to each other through the clutch housing CH. The airframe is supported by the front wheels FW and the rear wheels RW as “traveling devices”. A main clutch 2 described later is disposed inside the clutch housing CH, and a transmission mechanism TM described later is disposed inside the mission case MC.

  A driving section is provided at the rear of the fuselage, and a driving seat DS is provided. On the right side of the driver seat DS, a main transmission lever 19A and an auxiliary transmission lever 19B as “operation levers” are provided so as to be swingable back and forth and right and left along a lever guide described later. By operating the main transmission lever 19A, a transmission operation of the main transmission device 6 as a “transmission device” described later and a parking brake operation of the parking brake mechanism 17 described later are performed. By the operation of the auxiliary transmission lever 19B, an auxiliary transmission operation of the auxiliary transmission 8 described later is performed.

[About main clutch]
As shown in FIG. 2, the main clutch 2 is connected to the crankshaft 1 of the engine E and can be switched between an “on state” and a “cut off state”. When the main clutch 2 is in the “engaged state”, the rotational driving force (hereinafter referred to as “power”) from the engine E is transmitted to the transmission mechanism TM, and when in the “disengaged state”, no power is transmitted to the transmission mechanism TM. .

[About transmission mechanism]
The transmission mechanism TM is connected to the engine E via the main clutch 2 as shown in FIGS. 2 and 3, and the power of the engine E is only applied to the front wheel FW and the rear wheel RW or the rear wheel RW during traveling. It is possible to communicate. The transmission mechanism TM includes a propulsion shaft 3 disposed along the longitudinal direction of the machine body so as to have the same axis as the crankshaft 1, and an input shaft provided in parallel with the propulsion shaft 3 at the rear upper side of the propulsion shaft 3. 5 and behind the propulsion shaft 3, a cylindrical counter shaft 7 disposed in the same axis as the propulsion shaft 3 and in parallel with the input shaft 5, and in parallel with the counter shaft 7. An output shaft 9, a front wheel propulsion shaft 10 disposed in parallel with the output shaft 9, and a rear wheel propulsion shaft 11 directly connected to the rear of the output shaft 9 are provided. All the shafts are disposed along the longitudinal direction of the machine body and are rotatably supported by the mission case MC and the like.

  Power is transmitted from the crankshaft 1 to the propulsion shaft 3 via the main clutch 2, and further, the forward power (forward rotation) is maintained by the forward / reverse switching mechanism 4 provided around the propulsion shaft 3. Alternatively, it is converted into reverse power (reverse rotation). The forward / reverse switching mechanism 4 includes a forward clutch 4A and a reverse clutch 4B. When the forward clutch 4A is in the “engaged state” and the reverse clutch 4B is in the “disengaged state”, the power is transmitted from the propulsion shaft 3 to the input shaft 5 while maintaining the normal rotation. When the forward clutch 4A is in the “disengaged state” and the reverse clutch 4B is in the “engaged state”, the power is converted to reverse rotation and transmitted to the input shaft 5.

  The power transmitted to the input shaft 5 is shifted by the main transmission 6 from any one of “1st speed” to “6th speed” and transmitted to the counter shaft 7. The main transmission 6 will be described in detail later. The power transmitted to the counter shaft 7 is further shifted to either “high speed” or “low speed” by the auxiliary transmission 8 and transmitted to the output shaft 9. The power transmitted to the output shaft 9 is transmitted to the rear wheel propulsion shaft 11 as it is, and is also transmitted to the front wheel propulsion shaft 10 via an output gear 9a that is spline-fitted to the output shaft 9. The power transmitted to the rear wheel propulsion shaft 11 is transmitted to the rear wheel RW via the rear wheel differential device 12. The power transmitted to the front wheel propulsion shaft 10 is transmitted to the front wheels FW via a front wheel FW differential device (not shown).

  The transmission mechanism TM also has a PTO transmission system that extracts a part of the power and transmits it to a work machine (attachment). As shown in FIGS. 2 and 3, the transmission mechanism TM includes a PTO drive shaft 13 connected to the rear end of the propulsion shaft 3 in the same axial shape, and a PTO clutch 14 connected to the rear end of the PTO drive shaft 13. The PTO transmission shaft 15 is connected to the rear portion of the PTO clutch 14 and arranged in the same axis as the PTO drive shaft 13, and the PTO transmission shaft 15 is disposed below and in parallel with the PTO transmission shaft 15. And a PTO output shaft 16. The PTO drive shaft 13 is inserted into the cylindrical counter shaft 7 described above.

  When the main clutch 2 is in the “engaged state”, the power transmitted to the propulsion shaft 3 is transmitted to the PTO drive shaft 13 as it is regardless of the operation of the forward / reverse switching mechanism 4. The power transmitted to the PTO drive shaft 13 is transmitted to the PTO transmission shaft 15 and further to the PTO output shaft 16 when the PTO clutch 14 is in the “engaged state”. The power transmitted to the PTO drive shaft 13 is not transmitted to the PTO transmission shaft 15 when the PTO clutch 14 is in the “disengaged state”. The PTO clutch 14 can be switched between an “on state” and a “disengaged state” by a PTO clutch 14 lever (not shown).

[Main transmission]
The main transmission 6 is provided between the input shaft 5 and the counter shaft 7 as shown in FIGS. The main transmission 6 includes first to sixth gears 20a to 20f that are rotatably inserted with respect to the input shaft 5. From the front of the machine, the first 4th gear 20d, the first 3rd gear 20c, the first 6th gear 20f, the first 5th gear 20e, the first 2nd gear 20b, and the first 1st gear 20a are arranged in this order. It is. Further, a second shifter 22B is disposed around the input shaft 5 between the first 4th gear 20d and the first 3rd gear 20c, and between the first 6th gear 20f and the first 5th gear 20e. The third shifter 22C is disposed in the first shifter 22A, and the first shifter 22A is disposed between the first second gear 20b and the first first gear 20a.

  The second shifter 22B slides along the axial direction of the input shaft 5 by the operation of the second shift fork 46B (see FIGS. 3 and 6) by the speed change operation of the main speed change lever 19A. It is alternatively switched whether one of the first 4th speed gear 20d and the first 3rd speed gear 20c is connected or no gear is connected. That is, of the first 4th gear 20d and the 1st 3rd gear 20c, only the gear connected to the input shaft 5 is rotated by power.

  The third shifter 22C slides along the axial direction of the input shaft 5 by the operation of the third shift fork 46C (see FIGS. 3 and 6) by the speed change operation of the main speed change lever 19A. It is alternatively switched whether one of the first 6th gear 20f and the first 5th gear 20e is connected or neither gear is connected. That is, of the first 6th gear 20f and the first 5th gear 20e, only the gear connected to the input shaft 5 is rotated by power.

  The first shifter 22A slides along the axial direction of the input shaft 5 by the operation of the first shift fork 46A (see FIGS. 3 and 6) by the speed change operation of the main speed change lever 19A. It is alternatively switched whether one of the first second gear 20b and the first first gear 20a is connected, or which gear is not connected. That is, only the gear connected to the input shaft 5 among the first second gear 20b and the first first gear 20a is rotated by power.

  As will be described later, only one of the first shift fork 46A to the third shift fork 46C is configured to operate according to the speed change operation of the main speed change lever 19A. When in a state of being connected to any gear, the other two shifters are in a state of not connecting the input shaft 5 to any gear. Accordingly, only one of the first 1st gear 20a to the 1st 6th gear 20f rotates integrally with the input shaft 5 ("shift state" according to the present invention). When all the shifters are in a state where the input shaft 5 is not connected to any gear, the power of the input shaft 5 is not transmitted to any gear (“neutral state” according to the present invention).

  Further, as shown in FIGS. 2 and 3, the main transmission 6 is spline-fitted to the counter shaft 7 and rotates integrally with the counter shaft 7. 21f. Arranged in order of the second 4th gear 21d, 2nd 3rd gear 21c, 2nd 6th gear 21f, 2nd 5th gear 21e, 2nd 2nd gear 21b, 2nd 1st gear 21a from the front of the machine It is. The second 4th gear 21d is always engaged with the second 4th gear 21d, the second 3rd gear 21c is always engaged with the first 3rd gear 20c, and the second 6th gear 21f is engaged with the first 6th gear 20f. Always meshed, 2nd 5th gear 21e always meshed with 1st 5th gear 20e, 2nd 2nd gear 21b always meshed with 1st 2nd gear 20b, 2nd 1st gear 21a was 1st Always meshed with the speed gear 20a.

  With the above-described configuration of the main transmission 6, whether the power transmitted to the input shaft 5 is shifted between the first first gear 20a and the second first gear 21a and transmitted to the counter shaft 7 ("" 1st speed "), the first 2nd speed gear 20b and the 2nd 2nd speed gear 21b are shifted and transmitted to the counter shaft 7 (" 2nd speed "shifting state), or the 1st 3rd speed Whether the gear is shifted between the gear 20c and the second third gear 21c and transmitted to the counter shaft 7 ("third gear" shifting state), or between the first fourth gear 20d and the second fourth gear 21d Whether the gear is shifted and transmitted to the counter shaft 7 ("fourth speed" shift state), or is shifted between the first fifth gear 20e and the second fifth gear 21e and transmitted to the counter shaft 7. ("5-speed" shift state), the gear is shifted between the first 6-speed gear 20f and the second 6-speed gear 21f and transmitted to the counter shaft 7. Luke (shifting state of the "sixth speed"), or not transmitted to the counter shaft 7 (neutral state).

[About the auxiliary transmission]
As shown in FIGS. 2 and 3, the auxiliary transmission 8 is provided between the counter shaft 7 and the output shaft 9. The auxiliary transmission 8 is geared with the counter shaft 7 and rotates with a small diameter high-speed gear 30 that rotates in synchronization with the counter shaft 7, and a large diameter gear that directly meshes with the counter shaft 7 and rotates with the counter shaft 7. The low-speed gear 31 is provided in this order from the front of the aircraft. An auxiliary transmission shifter 32 is disposed around the output shaft 9 across the high speed gear 30 and the low speed gear 31. The auxiliary transmission shifter 32 slides along the axial direction of the output shaft 9 by the operation of the auxiliary transmission shift fork 48 (see FIGS. 3, 5, and 6) by the auxiliary transmission operation of the auxiliary transmission lever 19B, and outputs it. The shaft 9 and one of the high speed gear 30 and the low speed gear 31 are connected to each other, or any gear is not connected.

  With the configuration of the auxiliary transmission 8 described above, the power transmitted to the counter shaft 7 is shifted to “high speed” and transmitted to the output shaft 9 when the output shaft 9 and the high-speed gear 30 are connected ( When the output shaft 9 and the low-speed gear 31 are connected to each other, the speed is changed to “low speed” and transmitted to the output shaft 9 (so-called “low speed state”). When not connected to the gear, it is not transmitted to the output shaft 9 (so-called “neutral state (sub-shift)”).

[About cover members]
As shown in FIGS. 3 to 6, the right side surface of the mission case MC is constituted by a removable cover member 40, and if the cover member 40 is removed, a range indicated by a two-dot chain line in FIG. The vicinity of the lower part of the completed mission case MC) is opened. This configuration facilitates maintenance of the transmission mechanism TM.

[Configuration of main shift lever and operation shaft]
As shown in FIG. 12, the main transmission lever 19A is operated along a lever guide provided in the operation unit. That is, the main transmission lever 19A is operated along an operation path indicated by an arrow on the lever guide. The operation path of the main transmission lever 19A is roughly divided into two paths: a transmission operation path for performing the transmission operation of the main transmission 6 and a brake operation path for performing the brake operation of the parking brake mechanism 17.

  The speed change operation path corresponds to the “neutral state” of the main transmission 6, and extends from the neutral path 81 extending in the left-right direction of the machine body and from the neutral path 81 in a direction perpendicular to the neutral path 81 (the machine body longitudinal direction). And a shift path 80 corresponding to the “shift state” (“1st speed” to “6th speed”) of the main transmission 6. The brake operation path extends on an extension line of the neutral path 81, that is, extends in a direction perpendicular to the speed change path 80 (the left-right direction of the body), and the brake path 82 on which the parking brake mechanism 17 operates, and at least from the end of the brake path 82 A locking path that extends in a direction orthogonal to the braking path 82 (the longitudinal direction of the body) and that operates a locking mechanism 18 described later.

  The lock path includes a first lock path 83 extending from the end of the brake path 82 in a direction orthogonal to the brake path 82 (front-rear direction of the body), and a direction parallel to the neutral path 81 from the end of the first lock path 83 (left-right direction of the body). ) Along the neutral path 81 (inner side of the machine body). That is, the end of the lock path opposite to the end of the brake path 82 is folded back toward the neutral path 81.

  Next, a specific configuration of the main transmission lever 19A will be described. As shown in FIGS. 4 to 6, the main transmission lever 19 </ b> A is supported on the outer surface of the cover member 40 via a bracket 42 at a position slightly above the lower end. The bracket 42 is obtained by bending a relatively thick plate into a U-shaped cross section. The bracket 42 is firmly fixed to the cover member 40 with bolts at the lower portion of the inner surface in the left-right direction of the body and the lower portion of the outer surface in the left-right direction.

  The support shaft 43 is fixed in the posture in the left-right direction of the body over the inner and outer surfaces of the body 42 in the left-right direction (see FIG. 14). The end of the support shaft 43 on the outer side of the machine body protrudes from the outer surface of the bracket 42 toward the outer side of the machine body. The tip of the support shaft 43 can swing around the axis X of the support shaft 43 (the longitudinal direction of the machine body) and can swing around the axis Y perpendicular to the axis X (the machine body left-right direction). The main transmission lever 19A is supported.

  When the main transmission lever 19A is operated along the neutral path 81, the brake path 82, or the second lock path 84 (see FIG. 12), the main transmission lever 19A swings around the axis Y (the left-right direction of the machine body). Further, when the main transmission lever 19A is operated along the transmission path 80 or the first lock path 83 (see FIG. 12), the main transmission lever 19A swings around the axis X (the longitudinal direction of the machine body).

  As shown in FIG. 11, an operation shaft 44 as an “operation member” which is a bar member having a circular cross section is connected to the lower end portion of the main transmission lever 19A via a universal joint. The cover member 40 is formed with a boss portion 40a having a circular cross section along the left-right direction of the machine body, and the operation shaft 44 can be slidably and rotated with respect to the boss portion 40a in a state extending inside and outside the mission case MC. Interpolated. Further, a spring 45 as a “first urging mechanism” is disposed across the boss portion 40 a and the operation shaft 44. The urging force of the spring 45 acts on the main transmission lever 19A via the operation shaft 44. Due to the urging force of the spring 45, the main transmission lever 19 </ b> A is attached to the center side of the neutral path 81, that is, at the position that becomes the start end of the “3-speed” transmission path 80 and the start end of the “4-speed” transmission path 80. (See FIG. 12).

  With this configuration, when the main transmission lever 19 </ b> A is operated along the neutral path 81, the brake path 82, or the second lock path 84, the operation shaft 44 has an axial core that is located below the axial core X and that faces in the left-right direction. Slide along Z. That is, when the main transmission lever 19A is swung rightward, the operation shaft 44 slides toward the inside of the mission case MC, and when the main transmission lever 19A is swung leftward, the operation shaft 44 is moved to the mission case. Slide to the outside of the MC. Further, the operation shaft 44 rotates around the axis Z when the main transmission lever 19A is operated along the transmission path 80 or the first lock path 83. That is, when the main transmission lever 19A is swung forward, the operation shaft 44 is also rotated forward, and when the main transmission lever 19A is swung rearward, the operation shaft 44 is also rotated rearward. To do.

  As shown in FIGS. 11 and 14, at the end of the operation shaft 44 on the inside of the mission case MC, a shift portion 44 a is projected upward at the upper portion thereof, and a pin-shaped pressing portion is directed downward at the lower portion thereof. 44b is projected.

  As shown in FIGS. 6 and 9, the first shift fork 46 </ b> A to the third shift fork 46 </ b> C are individually supported on the inner side surface of the cover member 40 so as to be slidable in the front-rear direction of the machine body. When the first shift fork 46A is in the middle position of the slide movement range, the first shifter 22A is not connected to the input shaft 5 and the first second gear 20b and the first first gear 20a. It becomes. The same applies to the second shift fork 46B and the third shift fork 46C.

  As shown in FIG. 9, the shift portion 44a is engaged with the operating system of the first shift fork 46A and is engaged with the operating system of the second shift fork 46B as the operating shaft 44 slides. The position is changed between the position where the third shift fork 46C is engaged with the operation system and the position where the third shift fork 46 is not engaged with any operation system.

  When the main shift lever 19A is operated along the shift path 80 and swung back and forth with the shift portion 44a engaged with the operation system of the first shift fork 46A, the first shift fork 46A is moved from the intermediate position to the machine body. The input shaft 5 and the first second gear 20b or the first first gear 20a are coupled by sliding in the front-rear direction. That is, the body speed is changed to “first speed” or “second speed”.

  Similarly, when the main speed change lever 19A is operated along the speed change path 80 and swung back and forth while the shift portion 44a is engaged with the operation system of the second shift fork 46B, the second shift fork 46B is in the middle. The input shaft 5 and any one of the first 4th speed gear 20d and the first 3rd speed gear 20c are connected by sliding movement from the position in the longitudinal direction of the machine body. That is, the body speed is changed to “3rd speed” or “4th speed”.

  Further, when the main shift lever 19A is operated along the shift path 80 and swung back and forth with the shift portion 44a engaged with the operation system of the third shift fork 46C, the third shift fork 46C is moved to the intermediate position. The input shaft 5 and any one of the first 6th gear 20f and the first 5th gear 20e are connected. That is, the body speed is changed to “6th speed” or “5th speed”.

  As shown in FIGS. 9 and 10, the pressing portion 44 b is a first member of the parking brake mechanism 17, which will be described later, as the operating shaft 44 slides (operation along the brake path 82 of the main transmission lever 19 </ b> A). The pressed portion 61b (see FIGS. 7 and 8) 61 is pressed to swing the parking brake mechanism 17. When the main transmission lever 19A is operated along the first lock path 83, the pressing portion 44b merely slides and rotates along the pressed portion 61b following the rotation of the operation shaft 44. .

[About the sub-shift lever]
As shown in FIGS. 4 to 6, the auxiliary transmission lever 19 </ b> B has a lower end supported on the support shaft 43 described above so as to be swingable about the axis X. An auxiliary transmission shift fork 48 is supported on the inner side surface of the cover member 40 so as to be slidable in the longitudinal direction of the machine body. The auxiliary transmission lever 19 </ b> B and the auxiliary transmission shift fork 48 are linked by a link mechanism 47. When the auxiliary transmission lever 19 is swung back and forth, the auxiliary transmission shift fork 48 slides and moves in the longitudinal direction of the machine body (the axial direction of the output shaft 9) as described above.

  In a state where the auxiliary transmission lever 19B is swung most forward, the auxiliary transmission shifter 32 is in a state where neither the high speed gear 30 nor the low speed gear 31 is connected to the output shaft 9. From this state, when the auxiliary transmission lever 19B is swung rearward, the auxiliary transmission shifter 32 slides forward to enter the “low speed state”. When the auxiliary transmission lever 19B is further swung back from the “low speed state”, the auxiliary transmission shifter 32 slides further forward to enter the “high speed state”.

[About the parking brake mechanism]
The parking brake mechanism 17 is disposed inside the transmission case MC as shown in FIGS. 2 and 5, and meshes with the output gear 9 a that is spline-fitted to the output shaft 9 in the transmission mechanism TM. The operation of the transmission mechanism TM can be regulated. The structure of the parking brake mechanism 17 is demonstrated based on FIG. 7, FIG.

  The parking brake mechanism 17 includes a first member 61, a second member 62, a third member 63, and a fourth member 64.

  The first member 61 includes a shaft portion 61a and a pressed portion 61b. The shaft portion 61a protrudes toward the rear of the machine body, and its rear end is a partition member S (see FIG. 3) that divides the internal space of the mission case MC back and forth, and around the first axis L1 in the front-rear direction of the machine body. It is rotatably supported by. The pressed portion 61b is a shaft-like member that protrudes forward of the machine body above the shaft portion 61a. The pressed portion 61b can contact the above-described pressing portion 44b of the operation shaft 44 (see FIG. 10). A return spring 61c as a “second urging mechanism” is externally attached to the shaft portion 61a. The first member 61 is urged counterclockwise in front view by the urging force F1 of the return spring 61c (see the dotted arrows in FIGS. 7 and 8).

  That is, when the operating shaft 44 slides in the direction toward the inside of the mission case MC and the pressing portion 44b presses the pressed portion 61b in the direction toward the inside of the mission case MC, the first member 61 resists the biasing force F1. Oscillate clockwise around the first axis L1 (see the white arrow in FIG. 7). When the operating shaft 44 slides in the direction toward the outside of the mission case MC and the pressing force by the pressing portion 44b is released, the first member 61 swings counterclockwise by the urging force F1.

  The third member 63 includes a shaft portion 63a and a sliding portion 63b. The shaft portion 63a is provided so as to protrude rearward of the machine body, and a rear end portion thereof is supported by the partition member S so as to be rotatable around a second axis L2 parallel to the first axis L1. The sliding part 63b is projected in the front direction of the machine body and is in sliding contact with a later-described recess 64b of the fourth member 64.

  The second member 62 includes a first pin portion 62 a engaged with a loose hole at the upper end portion of the first member 61, and a second pin portion 62 b that comes into contact with the upper surface of the third member 63. The second member 62 is extrapolated to the shaft portion 63a of the third member 63, and is swingable relative to the third member 63 around the second axis L2.

  An auxiliary spring 63 c is extrapolated to the shaft portion 63 of the third member 63 in a state extending over the second member 62 and the third member 63. The urging force F3 of the auxiliary spring 63c acts on the third member 63 so as to swing counterclockwise relative to the second member 62 in a front view (dotted arrow in FIGS. 7 and 8). The second member 62 acts so as to swing clockwise relative to the third member 63 in a front view.

  That is, when the pressed portion 61b is pressed by the pressing portion 44b and the first member 61 swings clockwise, the second member 62 swings counterclockwise via the first pin portion 62a (FIG. 7). See the white arrow). At this time, since the second pin portion 62b tends to be separated from the upper surface of the third member 63, the third member 63 also swings counterclockwise following the second member 62 by the biasing force F3 of the auxiliary spring 63c. To do.

  The fourth member 64 is a member that meshes with the output gear 9a (see FIG. 10), and includes a shaft portion 64a, a concave portion 64b, and a claw portion 64c. The shaft portion 64a protrudes toward the rear of the machine body, and its rear end portion is pivoted around the third shaft core L3 parallel to the first shaft core L1 and the second shaft core L2 to the partition member S. It is supported. The concave portion 64b is formed on the surface opposite to the output gear 9a, and comes into contact with the sliding portion 63b to receive the sliding force. The claw portion 64c is formed on the surface of the output gear 9a and can be engaged with the output gear 9a. A return spring 64d as a “second urging mechanism” is externally inserted into the shaft portion 64a. The fourth member 64 is urged counterclockwise as viewed from the front by the urging force F4 of the return spring 64d (see the dotted arrows in FIGS. 7 and 8).

  That is, when the pressed portion 61b is pressed by the pressing portion 44b and the third member 63 swings counterclockwise, the sliding portion 63b slides in the recess 64b, and the fourth member 64 is It swings clockwise while resisting the urging force F4 (see the white arrow in FIG. 7).

  The parking brake mechanism 17 can so-called “overshift” the main transmission lever 19A so that the operation shaft 44 can slide to the inside of the mission case MC even after the claw portion 64c is engaged with the output gear 9a. It is configured as follows. In this case, the terminal side of the brake path 82 is an overshift path.

  In the case of overshift, the operating shaft 44 is further slid toward the inside of the mission case MC, so that the first member 61 swings clockwise and the second member 62 swings counterclockwise. However, since the fourth member 64 cannot swing further clockwise, the third member 63 does not swing further counterclockwise. Therefore, the second pin portion 62 b is separated from the upper surface of the third member 63. Thereby, the sliding movement of the operation shaft 44 to the inside of the mission case MC due to the overshift is absorbed. Further, at the time of this overshift, the second pin portion 62b and the upper surface of the third member 63 are separated from each other against the biasing force F3, and the biasing force is further charged to the auxiliary spring 63c.

  On the other hand, when the pressing force by the pressing portion 44b is released, the first member 61 swings counterclockwise by the biasing force F1. Since the loose hole of the first member 61 and the first pin portion 62a are engaged, the second member 62 and the third member 63 swing clockwise as the first member 61 swings. Further, the fourth member 64 swings counterclockwise by the biasing force F4. Thereby, the engagement of the claw portion 64c with the output gear 9a is released.

  The operation of the parking brake mechanism 17 based on the operation of the main transmission lever 19A will be described. When the main transmission lever 19A is positioned on the neutral path 81 or the transmission path 80, the pressing portion 44b and the pressed portion 61b are separated as shown in FIG. That is, the claw portion 64c is not engaged with the output gear 9a (“non-regulated state” according to the present invention). When the main transmission lever 19A is operated from the neutral path 81 to the brake path 82, the pressing portion 44b comes into contact with the pressed portion 61b, and the first member 61 to the fourth member 64 swing in conjunction with each other. When the main transmission lever 19A is positioned at the end of the brake path 82, as shown in FIG. 10, the claw portion 64c is engaged with the output gear 9a, the operation of the transmission mechanism TM is restricted, and the parking brake is applied (" Regulatory status ").

  The urging force of the spring 45 acts on the main transmission lever 19A regardless of the path of the main transmission lever 19A, but the urging force F1 of the return spring 61c and the urging force F4 of the return spring 64d Only works when the main transmission lever 19A is operated from the neutral path 81 to the brake path 82. Therefore, when performing the parking brake operation, the driver can sensuously grasp the boundary between the neutral path 81 and the brake path 82 by adding the urging force F4 of the return spring 61c and the urging force F4 of the return spring 64d.

[About the lock mechanism]
The lock mechanism 18 restrains the position of the main transmission lever 19A to maintain the parking brake mechanism 17 in the “restricted state”. As shown in FIGS. 4, 9, 11, 13, and 14, the lock mechanism 18 is fixed to the hook portion 52 as a “locking portion” connected to the operation shaft 44 and the bracket 42 described above. And a receiving portion 53 as a “locked portion”. The bracket 42 serves as a member that supports the main transmission lever 19A, a member that supports the auxiliary transmission lever 19B, and a member that supports the receiving portion 53.

  As shown in FIGS. 13 and 14, the receiving portion 53 is formed in a hat shape in a top view. A lower portion of the swinging fulcrum (shaft core X and shaft core Y) of the main transmission lever 19A is cut out in a rectangular shape on the outer surface of the bracket 42, and a protrusion of the receiving portion 53 is formed in the cutout portion. The remaining part is bolted to the bracket 42. An opening 53 a into which the hook portion 52 can enter is formed at a corner portion on the rear side of the body of the receiving portion 53.

  A plate-like support member 50 extending upward to the vicinity of the side portion of the bracket 42 is fixed to the upper surface of the end portion of the operation shaft 44, and further, on the inner side surface of the upper end portion of the support member 50 along the left-right direction of the body. A plate-shaped mounting member 51 is fixed. A hook portion 52 is fixed to the attachment member 51. The hook portion 52 is formed in a hook shape corresponding to the shapes of the brake path 82, the first lock path 83, and the second lock path 84 in a top view. Since the hook portion 52 is positioned below the swing fulcrum (the shaft core X and the shaft core Y) of the main transmission lever 19A, the hook shape of the hook portion 52 is the brake path 82 to the second path shown in FIG. The shape of the lock path 84 is point-symmetric. Note that it can be said that the operation shaft 44 and the lower end portion of the main transmission lever 19A are connected, and the hook portion 52 is connected to the lower end portion of the main transmission lever 19A.

  The operation of the lock mechanism 18 will be described with reference to FIGS. 13 (a) to 13 (d). When the speed change operation of the main speed change lever 19A is performed, that is, when the main speed change lever 19A is positioned in the neutral path 81 or the speed change path 80, as shown in FIG. 53. Therefore, the shifting operation of the main transmission lever 19A is not hindered by the lock mechanism 18.

  When the main transmission lever 19A is deviated from the neutral path 81 and operated to the end of the brake path 82 along the brake path 82 in order to apply the parking brake, as shown in FIG. It penetrates the notched portion and abuts on the protruding portion of the receiving portion 53. At this point, the parking brake mechanism 17 is in a restricted state.

  Subsequently, when the main transmission lever 19A is operated along the first lock path 83 from the terminal end of the brake path 82, the tip of the hook part 52 is received through the opening 53a as shown in FIG. 13C. To penetrate. Further, when the main speed change lever 19A is operated along the second lock path 84 from the end of the first lock path 83, as shown in FIG. To the outer peripheral portion of the opening 53a. As a result, the position of the main transmission lever 19 </ b> A is restrained, and the position of the operation shaft 44 is also fixed at a position where the parking brake mechanism 17 is in a restricted state.

  As described above, the parking brake mechanism 17 is configured to allow overshifting of the main transmission lever 19 </ b> A, and the overshift range is set longer than the second lock path 84. Therefore, when the main transmission lever 19A is operated from the end of the first lock path 83 along the second lock path 84, the operation shaft 44 slides to the outside of the mission case MC. The parking brake mechanism 17 is not swung to the “unregulated state” side. Further, the main transmission lever 19A located at the end of the second lock path 84 is prevented from unexpectedly moving toward the end of the first lock path 83 due to the charge of the urging force F3 based on the overshift.

[Removal of cover member]
As described above, the pressing portion 44b can be separated from the pressed portion 61b. Further, although not particularly illustrated, the first shift fork 46A to the third shift fork 46C and the auxiliary transmission shift fork 48 are respectively connected to the first shift fork 46A. The cover member 40 can be detached from the shifter 22A to the third shifter 22C and the auxiliary transmission shifter 32 in the removing direction of the cover member 40 (see FIG. 3), and the cover member 40 can be easily detached from the transmission case MC.

[First embodiment]
In the above-described embodiment, an example in which the auxiliary transmission 8 is switched between the high speed state, the low speed state, and the neutral state has been described. However, instead of the neutral state, the “ultra low speed state ( It may be configured to be switched to “creep state”. In this case, the subtransmission device 8 is provided with a creep mechanism 90 in order to reveal an ultra-low speed state.

  The creep mechanism 90 is configured to be removable from the cover member 40 as shown in FIG. The creep mechanism 90 includes a support member 91 that is removable with respect to the cover member 40, and a support shaft 92 that is rotatably supported by the support member 91 in a state along the front-rear direction of the body. A small diameter gear 93 and a large diameter gear 94 are supported on the support shaft 92 from the front of the machine body. The small diameter gear 93 is spline-fitted to the support shaft 92 and rotates integrally with the support shaft 92. The small diameter gear 93 is geared to the output shaft 9.

  The large diameter gear 94 is loosely fitted to the support shaft 92. The large diameter gear 94 is engaged with the output gear 9 a of the output shaft 9. Further, a creep shifter 95 is arranged between the small diameter gear 93 and the large diameter gear 94 so as to be slidable along the axial direction of the support shaft 92. When the creep shifter 95 is located between the small diameter gear 93 and the large diameter gear 94 and the small diameter gear 93 and the large diameter gear 94 are connected, the large diameter gear 94 rotates together with the small diameter gear 93.

  The creep shifter 95 is slid by a bifurcated shift fork 96. The bifurcated shift fork 96 is attached to the cover member 40 in place of the auxiliary transmission shift fork 48 in the above-described embodiment. The bifurcated shift fork 96 has a bifurcated tip portion, one tip portion is engaged with the auxiliary transmission shifter 32, and the other tip portion is engaged with the creep shifter 95. When one tip portion of the bifurcated shift fork 96 is in the neutral state in the above-described embodiment, the other tip portion is in a state where the creep shifter 95 spans the small diameter gear 93 and the large diameter gear 94. .

  That is, the power from the output shaft 9 is transmitted to the creep mechanism 90 via the small diameter gear 93, transmitted from the small diameter gear 93 to the large diameter gear 94 at the same rotational speed, and the large diameter gear 94 and the output gear 9a. And is returned to the output shaft 9 (super low speed state).

  In this way, the creep mechanism 90 is attached to the cover member 40, and the sub-shift shift fork 48 is replaced with the bifurcated shift fork 96. Thus, the “high speed state”, “low speed state”, and “ultra low speed state” can be achieved. Three sub-shifts are possible.

[Other alternative embodiments]
(1) The operation path of the main transmission lever 19A may not be as shown in FIG. For example, when the main transmission 6 is an HST (hydrostatic continuously variable transmission), the brake path 82 may be provided on the extension of the neutral path 81 as in the above-described embodiment. When the speed change path 80 is configured in a straight line and the neutral path 81 is a point, the brake path 82 may be extended from the neutral point in a direction intersecting the speed change path 80.

(2) In the above-described embodiment, the neutral path 81 and the speed change path 80 are “perpendicular”, and the speed change path 80 and the brake path 82 are “perpendicular (90-degree crossing)”. Even if they are not “orthogonal”, they need only be “crossed” at least.

(3) The main transmission 6 may not be capable of shifting to the sixth speed, but may be capable of shifting to the fifth speed or less and the seventh speed or more.

(4) In the above-described embodiment, the cover member 40 that is detachable from the mission case MC is provided and the right side portion of the mission case MC can be opened to the outside. However, the present invention is not limited to this. You may comprise so that the right side part of mission case MC cannot be opened without providing the cover member 40. FIG.

(5) In the above-described first alternative embodiment, the example in which the auxiliary transmission mechanism is attached afterwards has been described. However, the present invention is not limited to this, and the creep mechanism 90 may be provided from the beginning.

(6) The arrangement of the main transmission lever 19A and the auxiliary transmission lever 19B may be provided on either side of the driver seat DS.

(7) In the above-described embodiment, the example in which the hook portion 52 is attached to the end portion of the operation shaft 44 via the support member 50 or the attachment member 51 is shown, but the present invention is not limited to this. For example, although not particularly illustrated, the hook portion 52 may be supported by the main transmission lever 19A. In addition, the lock mechanism is not configured as the hook portion 52 and the receiving portion 53 as in the above-described embodiment, but may be any other mechanism as long as the position of the main transmission lever 19A or the operation shaft 44 can be restricted. It may be a configuration.

(8) The first urging mechanism includes the spring 45 interposed between the operation shaft 44 and the transmission case MC. The first urging mechanism directly applies an urging force to the main transmission lever 19A. It may be. In this case, it is preferable that the first urging mechanism is, for example, a spring provided over the main transmission lever 19A and the transmission case MC.

(9) In the above-described embodiment, the receiving portion 53 is supported by the transmission case MC via the bracket 42, but is not limited thereto. The receiving portion 53 may be fixed to another member as long as it is a member that is relatively stationary with respect to the operation shaft 44 and the main transmission lever 19A.

(10) Even if the parking brake mechanism 17 is not configured to mesh with the output gear 9a, the parking brake mechanism 17 may be configured to mesh with other gears or the like as long as the operation of the transmission mechanism TM can be regulated. Further, the parking brake mechanism 17 may not be configured to mesh with the gear but may be configured to be a friction plate type, for example.

  The present invention is not limited to a four-wheel drive tractor, but can be applied to a tractor including a crawler type traveling device instead of a rear wheel, and can also be applied to other work vehicles.

E Engine MC Mission case TM Transmission mechanism FW Front wheel (travel device)
RW Rear wheel (travel device)
6 Main transmission (transmission)
8 Sub transmission 9a Output gear (part of transmission mechanism)
17 Parking brake mechanism 18 Lock mechanism 19A Main transmission lever (operating lever)
19B Sub-transmission lever 42 Bracket 42
44 Operation shaft (operation member)
45 Spring (first biasing mechanism)
52 Hook part (locking part)
53 Receiving part (locked part)
53a Opening 61c Return spring (second biasing mechanism)
64d return spring (second biasing mechanism)
80 Shift path 81 Neutral path 82 Brake path 83 First lock path (lock path)
84 Second lock path (lock path)

Claims (10)

A transmission mechanism that is disposed inside the transmission case and transmits the rotational driving force from the engine to the traveling device;
A transmission that is arranged in the transmission mechanism and that can change the speed of the vehicle by changing the rotational driving force;
A parking brake mechanism disposed inside the transmission case and capable of regulating the operation of the transmission mechanism;
One operating lever that is manually swingable and capable of shifting the transmission and braking the parking brake mechanism;
The transmission case is supported by the transmission case in a state extending inside and outside the transmission case, and is connected to the operation lever so as to follow the operation of the operation lever, and is connected to the transmission mechanism and the parking brake mechanism. An operation member that is separately linked to transmit the operation of the operation lever to the transmission mechanism or the parking brake mechanism;
A lock mechanism capable of restraining the position of the operation lever or the operation member and maintaining the parking brake mechanism in a state in which the operation of the transmission mechanism is restricted;
As a speed change operation path of the operation lever, a neutral path corresponding to the neutral state of the transmission, and a speed change path extending linearly from the neutral path and corresponding to the speed change state of the transmission,
As a brake operation path of the operation lever, it extends from the neutral path in a direction crossing the speed change path, a brake path in which the parking brake mechanism operates, and at least extends from a terminal end of the brake path in a direction crossing the brake path. A work vehicle comprising: a lock path on which the lock mechanism operates.   The work vehicle according to claim 1, wherein an end portion of the lock path opposite to a terminal end of the brake path is folded back toward the neutral path. The transmission can shift the rotational driving force in a plurality of stages, and the neutral path is a linear path,
The parking brake mechanism is capable of changing its posture by swinging between a restricted state that engages with a part of the transmission mechanism and a non-restricted state that does not bite,
Providing the brake path on an extension of the neutral path;
When the operation lever is operated along the neutral path or the brake path, the operation member is configured to slide.
The work vehicle according to claim 1, wherein the operation member presses the parking brake mechanism by the sliding movement to change the posture of the parking brake mechanism from the non-regulated state to the restricted state.   A first urging mechanism that constantly urges the operation lever toward the center side of the neutral path and the first urging mechanism are provided separately from each other, and the operation lever is located when the operation lever is positioned in the brake path. The work vehicle according to claim 3, further comprising a second urging mechanism that urges the vehicle toward the neutral path. The first biasing mechanism is disposed across the transmission case and the operation member, and the second biasing mechanism is disposed in the parking brake mechanism.
The operation member and the parking brake mechanism are detachably linked, and when the parking brake mechanism is in the restricted state, the operation member and the parking brake mechanism are in contact with each other, and the parking brake mechanism is The work vehicle according to claim 4, wherein the operation member and the parking brake mechanism are separated from each other in the non-regulated state. The locking mechanism includes a locking portion connected to the operation member or the operation lever, and a locked portion fixed to a member that is stationary relative to the operation member and the operation lever. Prepared,
The end of the lock path opposite to the end of the brake path is folded back to the neutral path,
The structure according to any one of claims 1 to 5, wherein the locking portion is configured to be locked to the locked portion when the operation lever is operated in a folded path among the lock paths. The work vehicle described. The locking portion is formed in a hook shape corresponding to the shape of the brake path and the locking path, and an opening in which the locking portion can enter is formed in the locked portion,
When the operation lever is operated to the lock path, the locking part passes through the locked part through the opening, and the operation lever is further turned back in the lock path. The work vehicle according to claim 6, wherein the opening is configured so that the locking portion is locked to an outer peripheral portion of the opening when operated.   The work vehicle according to claim 6 or 7, wherein the operation lever is supported by a bracket fixed to the transmission case, and the locked portion is supported by the bracket.   The work vehicle according to any one of claims 6 to 8, wherein the operation member and the locking portion are connected to a lower end portion of the operation lever. A sub-transmission device different from the transmission device is provided in the transmission mechanism,
10. The work vehicle according to claim 1, wherein a bracket fixed to the transmission case pivotally supports the operation lever and a sub-transmission lever that operates the sub-transmission device.

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