JP4704983B2 - Shifting operation structure of walking type work machine - Google Patents

Description

  The present invention is a walking in which a steering handle is extended from the upper part of a mission case toward the rear of the fuselage, and a work device driven by power taken out from a PTO shaft provided in the mission case is connectable to the rear part of the fuselage. The present invention relates to a shift operation structure of a type work machine.

As the shift operation structure of the walking type work machine, for example, as shown in Patent Document 1, the shift operation shaft for travel shift supported by the transmission case is operated to the clutch engagement position of the PTO clutch lever. The check member is moved forward in conjunction with the engagement, engaged with the speed change operation shaft for traveling speed supported by the transmission case, and configured to prevent the reverse drive from being performed with the PTO clutch engaged. Are known.
Japanese Patent Laid-Open No. 10-250643 (FIG. 6, paragraph [0068])

  In the above speed change operation structure, the power from the PTO shaft provided in the transmission case is transmitted to the work device, and the PTO clutch provided in the work device is operated with the PTO clutch lever provided in the work device. The operation mechanism of the check member provided in the mission case and the work clutch lever provided on the work device side are linked by an operation wire, which requires many members for the reverse check means and increases the cost. . In addition, if the operation wire that links the PTO clutch lever and the restraining member is stretched, the restraining function may not be properly exhibited, and it is necessary to perform sufficient maintenance.

  The present invention has been made paying attention to such a point, and an object of the present invention is to provide a speed change operation structure capable of accurately performing the reverse check with a simple structure.

In the first aspect of the present invention, a working device driven by power extracted from a PTO shaft provided in the transmission case is provided at the rear of the self-propelled main unit extending the steering handle from the upper part of the transmission case toward the rear of the aircraft. In the shift operation structure of the walking work machine configured to be connectable,
The transmission case is equipped with a PTO clutch for intermittently driving power to the PTO shaft, and a plurality of speed change operation shafts for running and shifting, and a clutch operation shaft for turning on and off the PTO clutch are supported on the transmission case, and the reverse speed change. wherein during the speed change operation shaft and the clutch operating shaft, equipped with a reverse restrain means for engaging prevent the shift operation shaft in PTO clutch engaging state while moving to the rear Susumui location is to appear to perform,
The shift operation shaft is configured to be shiftable in the axial direction, the clutch operation shaft is configured to be rotatable, and the reverse operation of the shift operation shaft is performed by a check member integrally connected to the clutch operation shaft. The reverse check means is configured to prevent engagement to a position,
The clutch operating shaft is disposed below and below the speed change operating shaft, and an engaging member that is selectively engaged by a speed change lever is provided at a case outward projecting portion of the speed changing operation shaft. Forming the portion, and connecting and fixing the check member to the case outward projecting portion of the clutch operating shaft in a state of extending upward from the clutch operating shaft,
When the clutch operating shaft is rotated to the clutch engagement position, the upper end portion of the restraining member swings forward to perform the reverse shift, and the engaging portion of the engaging member of the speed change operating shaft shifts in the shift shift direction. The shift operation shaft is engaged with the rear side that intersects with the rear side to prevent the shift operation shaft from shifting to the reverse position .

According to the above configuration, it is possible to deploy the speed change operation shaft and a clutch operating shaft provided in the transmission case near the complex linkage structure to the reverse restraining means to equip between speed change operation shaft and the clutch operation shaft is not required For example, with a simple structure in which a check member is connected and fixed to the clutch operation shaft, and this check member is engaged with the speed change operation shaft or a member connected to the speed change operation shaft, the speed change operation shaft is It is possible to prevent movement to the reverse position.

Accordingly, specific and precise reverse restraining capable speed change operation structure can be composed of components less simple structure.

According to the above configuration, since the operation direction of the shift operation shaft for performing the reverse shift and the clutch operation shaft are different, the check member is connected to the shift operation shaft or to this by operating the clutch operation shaft to the clutch engagement position. The member can be engaged from the direction intersecting the moving direction, and the engagement check can be easily performed.

According to the above configuration, the engaging member provided on the speed change operation shaft for the speed change operation can be effectively used as the member engaged with the check member.

According to a second invention, in the first invention,
The engagement portion is formed on the engagement member so that the rear end of the engagement portion is located on the rear side of the axis of the clutch operation shaft .

According to a third invention, in the first or second invention,
The check member is selectively moved to the upper and lower two positions and fastened and fixed to the clutch operating shaft with a bolt, so that the attachment position of the check member can be changed between a lower check release position and an upper check production position. There is something.
According to a fourth invention, in the third invention,
A long dharma hole is formed in the restraining member in the vertical direction, and a circular positioning seat portion is formed in the head of the bolt to be fitted in the upper and lower hole portions of the dharma hole.

  According to the above configuration, when connecting a drive-type working device that does not expose the rotating operation part, such as a drug spraying device or a seeding device, to the rear of the self-propelled machine, the check member is released. By switching to the position, it becomes possible to carry out efficient work by freely performing reverse shift even when the PTO clutch is engaged.

  1 and 2, the entire side surface and the entire plane of the walking type working machine constructed by connecting the rotary tiller B, which is an example of the driving type working device, to the rear part of the self-propelled main machine A and having the tiller specifications are shown. Each one is shown. The self-propelled main machine A of this walking type working machine has an engine support frame 3 extending forward cantilevered from a mission case 2 on which left and right wheels 1 are pivotally supported. The engine 4 is mounted and connected, and an upper portion of the transmission case 2 has a structure in which a steering handle 5 that can be changed in the front-rear direction is extended in a cantilever direction. In this walking type work machine, the side where the engine 4 is present is basically the front of the machine, and the opposite direction is the rear of the machine. To be based on.

  As shown in FIG. 3, the engine 4 uses a recoil start type air-cooled gasoline engine in which the cylinder center is tilted rearward and is configured to be low in volume up and down. A fuel tank 6 (see FIG. 2) is provided so as to fill the gap between them.

  An output shaft 11 projecting to the left side of the engine 4 and an input shaft 12 projecting to the upper left side of the transmission case 2 are interlocked and connected by a belt transmission mechanism 14 having a tension clutch type main clutch 13. The entire belt transmission mechanism 14 is surrounded by a resin belt cover 15.

  A rear hitch 7 for connecting various working devices is provided at the rear part of the transmission case 2, and a front hitch 8 is provided at the front end of the engine support frame 3. The rotary tiller R is provided via the rear hitch 7. It is connected. Power taken out from a PTO shaft 19 (described later) that projects from the upper right side of the transmission case 2 is transmitted to the rotary tiller R through the chain case 9.

  4 to 7 show the transmission structure housed in the mission case 2. A back shaft 16 is disposed in front of the input shaft 12 disposed in the upper part of the mission case 2, a second shaft 17 is disposed below the back shaft 16, and further positioned below the input shaft 12. A third shaft 18 is provided. The right end portion of the input shaft 12 is concentrically supported by the inner end portion of the PTO shaft 19 supported through the bearing on the right side surface of the case, and the PTO shaft 19 is driven by the power of the input shaft 12 via the claw-engaged PTO clutch 20. To be communicated to.

  The PTO clutch 20 comprises a slide collar 21 with a pawl that is slidably fitted to the input shaft 12 and a clutch boss 22 with a pawl integrally formed on the inner end of the PTO shaft 19. The collar 21 is shifted to the right and engages with the clutch boss 22 to bring the clutch into a state where power is transmitted from the input shaft 12 to the PTO shaft 19, and the slide collar 21 is slid backward to the left. As shown in FIG. 5, by releasing the nail engagement, a clutch disengagement state in which power transmission from the input shaft 12 to the PTO shaft 19 is cut off is brought about.

  Between the input shaft 12, the back shaft 16, and the second shaft 17, there is interposed a main transmission mechanism 23 that shifts the second shaft 17 to two forward speeds and two reverse speeds. explain.

  A first shift gear SG1 having a small-diameter gear G1 and a large-diameter gear G2 is fitted on the input shaft 12 by a spline so as to be shiftable, and the second shaft 17 is selectively engaged with the small-diameter gear G1 and the large-diameter gear G2. The passive gears G3 and G4 are fixedly fitted. As shown in FIG. 5, when the first shift gear SG1 is in the neutral position, the small diameter gear G1 and the large diameter gear G2 are both disengaged from the passive gears G3 and G4, and the first shift gear SG1 is shifted from the neutral position to the right in the figure. Then, by engaging the small-diameter gear G1 with the passive gear G3, the second shaft 17 is driven at the first forward speed, and the first shift gear SG1 is shifted from the neutral position to the left in the figure to move the large-diameter gear G2 to the passive gear. By engaging with G4, the second shaft 17 is driven at the second forward speed.

  A second shift gear SG2 having a small diameter gear G5 and a large diameter gear G6 is fitted on the back shaft 16 by a spline so as to be shiftable. The large-diameter gear G2 of the first shift gear SG1 and the large-diameter gear G6 of the second shift gear SG2 are each configured to be wide so that they are always meshed regardless of how the first and second shift gears SG1 and SG2 are shifted. 16 is rotationally driven in the direction opposite to the input shaft 12. As shown in FIG. 5, when the second shift gear SG2 is in the neutral position, the small diameter gear G5 and the large diameter gear G6 are both disengaged from the passive gears G3 and G4, and the second shift gear SG2 is shifted from the neutral position to the right in the figure. Then, by engaging the small-diameter gear G5 with the passive gear G3, the second shaft 17 is driven at the first reverse speed, the second shift gear SG2 is shifted from the neutral position to the left in the figure, and the large-diameter gear G6 is moved to the passive gear G4. The second shaft 17 is driven at the second reverse speed.

Between the second shaft 17 and the third shaft 18, an auxiliary transmission mechanism 24 for shifting the power from the second shaft 17 in three stages is interposed, and the transmission structure will be described below.
A small-diameter gear G7, a large-diameter gear G8, and a small-diameter wide gear G9 are loosely supported on the second shaft 17, respectively. On the third shaft 18, the small-diameter gear G7, the large-diameter gear G8, and Passive gears G10, G11, and G12 that are always engaged with each of the small-diameter wide gear G9 are mounted. While the passive gears G10 and G11 are fixed to the third shaft 18, the passive gear G12 is loosely fitted to the third shaft 18, and an output sprocket 25 is integrally connected to the passive gear G12. Yes. A large-diameter gear G13 is integrally connected to the small-diameter wide gear G9, and this large-diameter gear G13 is always meshed with a pinion gear G14 formed integrally with the third shaft 18.

  The second shaft 17 is configured as a cylindrical shaft, and a speed change operation shaft 26 is inserted from the left end thereof so as to be shiftable in the axial direction, and the inner end portion of the speed change operation shaft 26 is disposed inside the second shaft 17. A collar member 28 slidably contacting the periphery is connected. The collar member 28 incorporates a transmission key 27 that can be moved back and forth in the radial direction and that is projected and urged by an internal spring 29. The transmission key 26 is shifted in the axial direction to shift the transmission key. 27 is engaged from the inner periphery with any one of the small-diameter gear G7, the large-diameter gear G8, and the small-diameter wide gear G9.

  In a state in which the speed change operation shaft 26 is pushed inward and shifted inward, the transmission key 27 is engaged with the inner periphery of the small diameter gear G7, and the second shaft 17 and the small diameter gear G7 are integrated. As a result, the power of the second shaft 17 is transmitted to the third shaft 18 via the small diameter gear G7 and the passive gear G10. The power transmitted to the third shaft 18 is decelerated and transmitted to the small-diameter wide gear G9 via the pinion gear G14 and the large-diameter gear G13, and further decelerated via the small-diameter wide gear G9 and the passive gear G12. Driven at low speed.

  As shown in FIG. 5, when the speed change operation shaft 26 is slid to the left and right intermediate position, the transmission key 27 is engaged with the inner periphery of the large diameter gear G8, and the second shaft 17 and the large diameter gear G8 are integrated. It becomes. As a result, the power of the second shaft 17 is transmitted to the third shaft 18 via the large-diameter gear G8 and the passive gear G11. The power transmitted to the third shaft 18 is decelerated and transmitted to the small-diameter wide gear G9 via the pinion gear G14 and the large-diameter gear G13, and further decelerated via the small-diameter wide gear G9 and the passive gear G12. Driven at medium speed.

  In a state in which the speed change operation shaft 26 is pulled out and shifted most outward, the transmission key 27 is engaged with the inner periphery of the small-diameter wide gear G9, and the second shaft 17 and the small-diameter wide gear G9 are integrated. As a result, the power of the second shaft 17 is directly transmitted to the passive gear G12 through the small-diameter wide gear G9, and the output sprocket 25 is driven at a high speed.

  In this way, the subtransmission mechanism 24 shifts the power transmitted to the second forward speed and the second reverse speed by the main transmission mechanism 23 to the second shaft 17 and further transmits the power to the output sprocket 25 by shifting to the third speed. It is composed.

The speed change power taken out from the output sprocket 25 is transmitted to the left and right axles 29 supported under the mission case 2 as follows.
As shown in FIGS. 4 and 6, the left and right axles 29 are concentrically opposed to each other, and an intermediate support shaft 30 is inserted across the two axles 29. A passive sprocket 32 that is externally fitted so as to freely rotate across the abutting portions of both axles 29 and the output sprocket 25 are wound and interlocked via a chain 33.

  The passive sprocket 32 and the left and right axles 29 are linked to each other via a ball-type side clutch 34. By inserting both side clutches 34, the left and right axles 29 are driven integrally to travel straight, The vehicle body is steered by one-wheel drive by disengaging the side clutch 34 and putting one axle 29 in the idle state.

  The side clutch 34 has a clutch boss 35 extending left and right from the passive sprocket 32, a transmission ball 36 engaged and supported at a plurality of locations in the circumferential direction of the clutch boss 35, and a shiftable outer fit on the outer periphery of the clutch boss 35. The operation collar 37 is mounted, and a clutch spring 38 that biases and shifts the operation collar 37 outward in the axial direction. Normally, as shown in the left half of FIG. 6, the operation collar 37 is shifted outward by the clutch spring 38, so that the transmission ball 36 is pushed inward in the radial direction on the inner periphery of the operation collar 37. Thus, the transmission ball 36 is engaged with the clutch boss 35 over the transmission groove 29 a formed on the outer periphery of the axle 29, resulting in a clutch engagement state in which transmission from the passive sprocket 32 to the axle 29 is performed. As shown in the right half of FIG. 6, when the operation collar 37 is shifted inward against the clutch spring 38, the pushing of the transmission ball 36 due to the inner periphery of the operation collar 37 is released, and the transmission ball 36. Can be retracted to the inner circumferential space 39 of the operation collar 37, and the transmission ball 36 escapes from the transmission groove 29a of the axle 29, thereby bringing about a clutch disengagement state in which the transmission from the passive sprocket 32 to the axle 29 is interrupted.

Next, the operation structures of the main clutch 13, the PTO clutch 20, the main transmission mechanism 23, the auxiliary transmission mechanism 24, and the side clutch 34 will be described.
[Main clutch operation structure]
As shown in FIGS. 11 and 12, a main clutch lever 42 is disposed on the left side of the steering handle 5 via a bracket 41 so as to be able to swing back and forth around a lateral fulcrum a, from the base end of the main clutch lever 42. One end of the curved link 40 is pivotally connected to the extended operating member 43, and the other end of the curved link 44 and the tension arm 13a of the main clutch 13 are connected to the operation wire 44 and the spring 45 for absorbing the stroke (see FIG. 3). It is linked and connected through.

  As shown in FIG. 12, by operating the main clutch lever 42 to the clutch disengagement position OFF that greatly exceeds the dead point DP, the operation wire 44 is loosened and the tension arm 13a is swung downward by its own weight. By operating the main clutch lever 42 to the clutch engagement position ON slightly beyond the dead point DP, the operation wire 44 is pulled rearward to swing the tension arm 13a upward.

  The bracket 41 is provided with an auxiliary clutch lever 46 that can be pushed down with the thumb of the hand gripping the left grip portion 5g of the steering handle 5 so as to be swingable around the lateral fulcrum b and to be able to return and rise. The auxiliary clutch lever 46 is linked to the main clutch lever 42 so that the main clutch lever 42 can be forcibly swung from the current operation position to the opposite position every time the push-down operation is performed. Even while holding 5, the main clutch 13 can be turned on and off by the finger operation of the left hand.

  An arch-shaped check lever 48 is provided over brackets 41 and 47 provided on the left and right of the steering handle 5. The check lever 48 is configured to forcibly swing the main clutch lever 42 to the clutch disengagement position OFF when the main clutch lever 42 is swung forward with the clutch engagement position ON. When the aircraft moves backward without the operator moving, the check lever 48 is pushed by the operator and swung relatively forward, so that the main clutch 13 is automatically disengaged and the reverse movement is stopped. It is like that.

[PTO clutch operation structure]
As shown in FIG. 8, the shift fork 51 engaged with the slide collar 21 in the PTO clutch 20 is externally fitted to the clutch operating shaft 52 penetrating and supported by the transmission case 2 so as to be slidable. The clutch operating shaft 52 is obstructed in a state where it can rotate and is prevented from moving outward from the case, and the shift fork 51 is engaged with the clutch operating shaft 52 by a spring 53 that is externally fitted (see FIG. 8). The left end of the base end boss 51 a provided with the shift fork 51 is received and supported by the operation pin 54 that is driven through the clutch operation shaft 52.

  An inclined cam portion 55 is formed at the left end of the base end boss portion 51a. When the clutch operation shaft 52 is rotated in a predetermined direction, the operation pin 54 rotates in the same direction and the inclined cam portion. By pressing and pressing 55, the shift fork 51 is shifted in the clutch engagement direction (to the right in FIG. 8) against the spring 53, the side clutch 20 is engaged, and the predetermined direction toward the clutch operating shaft 52 is reached. When the pivoting operation is released, the proximal boss portion 51a is shifted in the clutch disengagement direction by the restoring force of the spring 53, and the operation pin 54 is pressed by the inclined cam portion 55, so that the clutch operation shaft 52 is reversed. It is designed to rotate in the direction.

  An operation arm 56 is fixed to a protruding portion of the clutch operation shaft 52 outside the case. The operation arm 56 attaches an operation wire 58 to a PTO clutch lever 57 that is pivotally supported on the right side of the steering handle 5 so as to be able to swing back and forth. It is linked and connected through. The PTO clutch lever 57 is arbitrarily switched between a clutch disengagement position OFF that greatly exceeds the dead point DP rearward and a clutch engagement position ON that is slightly beyond the dead point DP forward, and is held at that operation position. Can be kept. When the PTO clutch lever 57 is operated largely rearward, the operation wire 58 is loosened, and the inclined cam portion 55 slidably urged by the spring urging force presses the operation pin 54, as shown in FIG. Then, the clutch operation shaft 52 is rotated in the clockwise direction and is held at the clutch disengagement position OFF. When the PTO clutch lever 57 is operated largely forward, the operation wire 58 is pulled, and as shown in FIG. 10 (b), the clutch operation shaft 52 is rotated counterclockwise and switched to the clutch disengagement position OFF.

[Main / sub transmission mechanism operation structure]
As shown in FIG. 7, in the main transmission mechanism 23, the first shift gear SG1 that performs two forward shifts and the second shift gear SG2 that performs two reverse shifts are a first shift fork 61 and a second shift fork, respectively. The shift operation shaft 63 for forward shifting, to which the first shift fork 61 is fixed, and the shift operation shaft 64 for reverse shifting, to which the second shift fork 62 is fixed, are respectively connected to the left side of the transmission case 2. It is supported on the wall so that it can shift left and right. As shown in FIG. 10, a shift operation shaft 64 for reverse shift is disposed above the input shaft 12, and a shift operation shaft 63 for forward shift is disposed above the back shaft 16. And the second shift fork 62 extend so as to cross each other when viewed from the side.

  As shown in FIG. 7, two sets of detent balls 66 urged by a spring 65 are mounted on the left side wall of the mission case 2. The detent ball 66 is urged and engaged with any one of three annular grooves 67 formed at intervals corresponding to the shift pitch on the outer periphery of each of the speed change operation shafts 63 and 64, whereby each speed change operation shaft 63. , 64 are held stably at the two shift positions F1, F2, R1, R2 and the neutral position N. The spring 65 and the detent ball 66 are incorporated from the inside of the case into a recessed portion 68 that is formed open to the inner surface of the case side wall, and the recessed portion 68 is closed by a common contact plate 69 that is bolted from the inside of the case. 65 and the detent ball 66 are prevented from coming out.

  Block-like engaging members 71 and 72 are fixed to the outward projecting portions of the respective speed change operation shafts 63 and 64 for main speed change, and both the engaging members 71 and 72 are disposed close to each other in the front-rear direction. A cam plate 73 is connected to the outward projecting portion of the speed change operation shaft 26 for the auxiliary speed change in a rearward downward inclined posture.

  As shown in FIG. 3 and FIG. 17 to FIG. 21, a transmission operation member 74 is pivotally mounted near the upper rear end on the left lateral outer side in the mission case 2 so as to be rotatable around a lateral fulcrum p. A rotating member 75 is supported on the vertical boss 74a provided to the boss 74a so as to be rotatable only about the vertical axis q, and the base end of the speed change lever 76 is supported on the rotating member 75 and the boss 74a. The vertical axis portion 76a is inserted and connected. The base end vertical axis portion 76a of the transmission lever 76 is supported so as to be vertically slidable with respect to the rotating member 75, and is slid downward by an internal spring 77. The base end vertical axis portion 76a slides downward. Then, the serration portion 76b formed on the outer periphery of the base end longitudinal axis portion 76a is fitted into the serration hole 75a of the rotation member 75, so that the speed change lever 76 and the rotation member 75 are arranged around the longitudinal axis q. It becomes possible to rotate integrally, and by lifting the proximal end longitudinal axis portion 76a upward against the spring 77, the serration portion 76b of the proximal end longitudinal axis portion 76a is detached upward from the serration hole 75a of the rotational member 75, The speed change lever 76 can be turned around the longitudinal axis q to be changed to the same direction as the steering handle 5.

  A main transmission operating member 78 having a sheet metal structure is pivotally connected to the rotating member 75 so as to freely swing up and down around a lateral fulcrum t. Engagement pieces 78a, 78b, and 78c are bent downward from three positions before and after the main speed change operation member 78, and these engagement pieces 78a, 78b, and 78c are selected as the engagement members 71 and 72, respectively. It is designed to be engaged. The engaging members 71 and 72 are provided with engaging grooves 71a and 72a that allow the engaging pieces 78a, 78b, and 78c to move in the front-rear direction and engage the engaging pieces 78a, 78b, and 78c so that they cannot move left and right. The guide members 71b and 72b are formed on the engaging members 71 and 72 so as to receive the engaging pieces 78a, 78b and 78c of the main speed change operation member 78 swinging downward under its own weight. When both the speed change operation shafts 63 and 64 are in the neutral position, the engagement grooves 71a and 72a of the both engagement members 71 and 72 are aligned in the front-rear direction, and the engagement pieces 78a, 78b, 78c are moved forward and backward. Is possible.

  A gauge pin 79 is erected upward from the main speed change operation member 78, and the guide groove 81 of the speed change guide plate 80 fixedly arranged on the upper part of the transmission case 2, and further the speed change fixedly arranged on the guide groove 81. A gauge pin 79 is inserted into the guide groove 96 of the display plate 95.

The speed change operating member 74 and the speed change operation shaft 26 for auxiliary speed change are interlocked and connected via a cam mechanism 83. The cam mechanism 83 includes the cam plate 73 connected to the speed change operation shaft 26, and one speed change operation pin 82 extending from the lower end portion of the speed change operation member 74 . The free end side is guided and engaged with a guide member 85 connected and fixed to the transmission case 2 so as to be movable in the left-right direction, so that the cam plate 73 is always maintained in a constant posture regardless of the shift in the axial direction of the speed change operation shaft 26. It has become so.

  As shown in FIGS. 14 to 16, the cam plate 73 is formed with a step-like cam groove 84 that is long in the front-rear direction, and a speed change operation pin 82 is engaged with the cam groove 84. Accordingly, when the shift operation pin 82 swings around the lateral fulcrum p by the vertical swing operation of the shift lever 76, the cam plate 73 is relatively moved to the left and right by the guide action of the cam groove 84, and the shift operation shaft 26 is moved. It is designed to be shifted left and right.

  Specifically, as shown in FIG. 14, when the speed change lever 76 is operated in the lower region, the speed change operation pin 82 is positioned in the upper guide portion 84 u of the cam groove 84, and the speed change operation shaft 26 is greatly pushed and shifted. Thus, the auxiliary transmission mechanism 24 is switched to “low speed”. As shown in FIG. 15, when the speed change lever 76 is operated to the upper and lower intermediate region, the speed change operation pin 82 is positioned at the intermediate guide portion 84m of the cam groove 84, and the speed change operation shaft 26 is pulled out to the left and shifted. The speed change mechanism 24 is switched to “medium speed”. Further, as shown in FIG. 16, when the speed change lever 76 is operated to the upper region, the speed change operation pin 82 is positioned in the lower guide portion 84d of the cam groove 84, and the speed change operation shaft 26 is further pulled out and shifted to the left. Thus, the auxiliary transmission mechanism 24 is switched to “high speed”.

  As shown in FIG. 17, when the shift lever 76 is operated to the lowermost shift range at the neutral position at the center of the left and right, the foremost engagement piece 78a moves forward with the subtransmission mechanism 24 switched to "low speed". In this state, the shift lever 76 is swung to the left and right to shift the shift operation shaft 63 that has been selectively engaged, thereby shifting the first forward speed. Shifting between F1 and the second forward speed F2 can be performed.

  As shown in FIG. 18, when the speed change lever 76 is returned to the neutral position at the center of the left and right and is operated one step upward, the engagement piece 78b between the front and rear is moved backward while the subtransmission mechanism 24 is maintained at “low speed”. In this state, the shift lever 76 is swung to the left and right to shift the shift operation shaft 64 that has been selectively engaged, so that the first reverse speed is achieved. R1 and reverse 2nd speed R2 can be changed.

  As shown in FIG. 19, when the shift lever 76 is returned to the neutral position at the center of the left and right and is further moved upward by one step, the engagement piece 78b between the front and rear is engaged in the state where the sub-transmission mechanism 24 is switched to "medium speed". Is selectively engaged with the forward shifting engagement member 71. In this state, the shift lever 76 is swung left and right to shift the selectively engaged shift operation shaft 63 to move forward. Shifting between the third speed F3 and the forward fourth speed F4 can be performed.

  As shown in FIG. 20, when the speed change lever 76 is returned to the neutral position at the center of the left and right and is further moved upward by one step, the rearmost engagement piece 78b is maintained with the sub-speed change mechanism 24 maintained at "medium speed". Is selectively engaged with the reverse shift engagement member 72. In this state, the shift lever 76 is swung left and right to shift the selectively engaged shift operation shaft 64, thereby moving the reverse shift. Shifting between the third speed R3 and the reverse fourth speed R4 can be performed.

  As shown in FIG. 21, when the speed change lever 76 is returned to the neutral position at the center of the left and right and is operated to the uppermost operating range, the rearmost engagement piece 78c in the state where the auxiliary speed change mechanism 24 is switched to "high speed". Is selectively engaged with the forward shifting engagement member 71. In this state, the shift lever 76 is swung left and right to shift the selectively engaged shift operation shaft 63 to move forward. Shifting between the fifth speed F5 and the sixth forward speed F6 can be performed.

  That is, in this embodiment, the main transmission mechanism 23 capable of shifting two forward speeds and two reverse speeds and the auxiliary transmission mechanism 24 capable of three speed shifting are combined, so that the total of six forward speeds and four reverse speeds are achieved. It is configured to perform the multi-stage shift.

  As shown in FIGS. 17 to 21 and 24, a display portion 97 protruding in a mountain shape is provided on the lateral side of the guide groove 96 formed in the transmission display plate 95. The gear stage is displayed on the backward slope r of the display unit 97 so as to be readable from the rear of the aircraft, and the gear stage is displayed on the forward slope surface f of the display unit 97 so as to be readable from the front of the aircraft. In the basic state in which the rearward is extended backward, the shift position can be recognized by comparing the position of the gauge pin 79 with the display of the rearward inclined surface r of the display unit 97, and the steering handle 5 and the shift lever 76 are reversed in the reverse direction. The shift position can be recognized by comparing the position of the gauge pin 79 with the display of the forward slope f of the display unit 97.

[Side clutch operation structure]
As shown in FIGS. 4 and 6, the operating collars 37 in the left and right side clutches 34 are engaged with shift forks 87 supported in the mission case 2 so as to be swingable around a fulcrum s in the front-rear direction. An upper end portion of each shift fork 87 is linked to a clutch operation shaft 88 mounted on the upper and lower intermediate portions of the left and right side surfaces of the mission case 2 via an operation rod 89. The operating arm 90 provided outside the clutch operating shaft 88 and the grip levers 91 provided on the left and right sides of the steering handle 5 are wire-coupled to operate the grip portion 5g of the steering handle 5 and the grip lever 91 together. Thus, the side clutch 34 on the gripped side is operated to be turned off.

  This walking work machine is provided with a reverse check means having the following structure for preventing the reverse drive while the rotary tiller B is driven.

  That is, as shown in FIG. 10, the vertical wall-shaped rib 72 c is integrally formed on the rear side of the engaging member 72 of the speed change operation shaft 64 that performs the reverse speed change in the main speed change. As shown in FIG. 9, the clutch operation shaft 52 arranged at the lower rear side of the speed change operation shaft 64 is extended outward from the connection position of the operation arm 56, and is formed on a flat surface 52 a formed by cutting on the outer periphery of the extension portion. A steel plate restraining member 98 is fastened and fixed by a bolt 99. A mounting hole 100 of the restraining member 98 is formed in a vertically long dharma hole, and a circular positioning seat 99a that fits into the mounting hole 100 is formed on the head of the bolt 99, and the bolt 99 is loosened. Then, by removing the positioning seat portion 99a from the mounting hole 100, the restraining member 98 can be selectively moved to the upper and lower two positions to be fastened and fixed.

  As shown in FIG. 10, when the check member 98 is fixed at the upper check production position, the turning locus of the check member 98 interferes with the shift movement locus of the rib 72c. As shown, when the clutch operation shaft 52 is turned to the clutch disengagement position OFF, the restraining member 98 is disengaged rearward from the rib 72c, and the shift operation shaft 64 for the reverse shift can be arbitrarily shifted. It becomes a state. That is, the reverse shift can be arbitrarily performed in the PTO clutch disengaged state.

  As shown in FIG. 10 (b), when the shift operation shaft 64 is in a neutral state and the clutch operation shaft 52 is turned to the clutch engagement position ON, an engagement recess 98a formed at the upper end of the check member 98 is an engagement member. 72, the shift operation shaft 64 is prevented from being shifted from the neutral position to the shift position. That is, it is impossible to perform reverse gear shifting when the PTO clutch is engaged. On the contrary, in the state where the shift operation shaft 64 is shifted from neutral to inward or outward and the reverse shift is selected, the clutch operation shaft 52 at the clutch disengagement position OFF is operated to be turned to the clutch engagement position ON. The leading end of the restraining member 98 contacts the edge of the rib 72c, and the rotation to the clutch engagement position ON is prevented. In other words, it is possible to prevent a reverse state from appearing while the PTO clutch is engaged.

  When the restraining member 98 is fixed at the lower restraining release position, the pivoting locus of the restraining member 98 moves to a position deviating downward from the rib 72c, and even if the restraining member 98 is pivoted together with the clutch operating shaft 52, the restraining member is moved. 98 does not interfere with the rib 72c, and the shift operation shaft 64 for reverse shift can be arbitrarily shifted regardless of whether the PTO clutch 20 is turned on or off.

[Other Examples]
(1) The operating structure of the PTO clutch 20 can be configured as shown in FIG. In other words, the clutch operating shaft 52 is supported by the transmission case 2 having a left and right split structure so that the clutch operating shaft 52 can rotate and shift, and the clutch operating shaft 52 is concentrically surrounded by the inner surface of the left case side wall. A cam portion 55 is integrally formed, and projecting portions of both ends of the operation pin 54 driven into the clutch operation shaft 52 are received and supported by the inner end portion of the cam portion 55. As shown in FIGS. 26 and 27, the cam portion 55 has two sets of trapezoidal peaks 55a and valleys 55b alternately formed with a phase difference of 180 °, and the flat top and valleys of the trapezoidal peaks 55a. The bottom surface of the portion 55b is connected by an inclined cam surface 55c. Therefore, when the clutch operation shaft 52 is rotated so that the protruding portions at both ends of the operation pin 54 are in a rotation phase that falls into the valley portion 55b, the clutch operation shaft 52 and the shift fork 51 are urged and slid to the clutch disengagement position. When the clutch operating shaft 52 is forcibly rotated from this rotational phase, the projecting portions of both ends of the operating pin 54 move up to the inclined cam surface 55 c, thereby causing the clutch operating shaft 52 and the shift fork 51 to resist the spring 53. Then, it is moved to the clutch engagement position.

  (2) The check member 98 and the rib 72c are engaged with each other via an inclined cam, and the clutch operation shaft 52 is moved from the clutch disengagement position OFF to the clutch engagement position ON with the speed change operation shaft 64 in the reverse position. When the rotation operation is forcibly performed, the shift operation shaft 64 in the reverse drive position can be neutrally forcibly shifted by the cam action of the inclined cam.

Overall side view of walking type work machine Overall plan view of walking type work machine Side view of the top of the aircraft Longitudinal rear view of the mission case Expanded sectional view of the top of the mission case Longitudinal section at the bottom of the mission case Cross-sectional plan view of the main transmission operating section Cross-sectional plan view showing PTO clutch operation structure Exploded perspective view showing the structure for mounting the check bracket on the clutch operating shaft Side view showing check release state (b) and check state (b) of reverse shift check structure Plan view showing the rear of the steering handle Side view showing the hand clutch operating structure Side view showing the hand operation structure of the PTO clutch Longitudinal rear view showing the low-speed state of the sub-transmission operation unit Longitudinal rear view showing the medium speed state of the sub-transmission operation unit Longitudinal rear view showing the high-speed switching state of the sub-shift operating unit Longitudinal side view showing the forward low speed state of the speed change operation structure Longitudinal side view showing the reverse low speed state of the shift operation structure Longitudinal side view showing the middle forward speed state of the speed change operation structure Longitudinal side view showing the reverse and middle speed state of the speed change operation structure Longitudinal side view showing the forward high speed state of the shift operation structure Top view of the shift operation structure Top view of the shift guide plate Top view of the shift display Cross-sectional plan view showing another embodiment of the PTO clutch operation structure Side view showing cam structure for PTO clutch operation Developed cam structure

2 Transmission case 5 Steering handle 19 PTO shaft 20 PTO clutch 52 Clutch operation shaft 63 Shift operation shaft 64 Shift operation shaft 71 Engagement member 72 Engagement member
72c rib (engagement part)
76 Shift lever 98 Checking member
99 volts
99a Positioning seat
100 Mounting hole (Dharma hole)
A Self-propelled machine R Working device (Rotary tillage device)

Claims (4)

A walk that is configured to be able to connect a work device driven by power extracted from the PTO shaft provided in the mission case to the rear part of the self-propelled machine that extended the steering handle from the top of the mission case toward the rear of the aircraft In the shift operation structure of the type work machine,
The transmission case is equipped with a PTO clutch for intermittently driving power to the PTO shaft, and a plurality of speed change operation shafts for running and shifting, and a clutch operation shaft for turning on and off the PTO clutch are supported on the transmission case, and the reverse speed change. wherein during the speed change operation shaft and the clutch operating shaft, equipped with a reverse restrain means for engaging prevent the shift operation shaft in PTO clutch engaging state while moving to the rear Susumui location is to appear to perform,
The shift operation shaft is configured to be shiftable in the axial direction, the clutch operation shaft is configured to be rotatable, and the reverse operation of the shift operation shaft is performed by a check member integrally connected to the clutch operation shaft. The reverse check means is configured to prevent engagement to a position,
The clutch operating shaft is disposed below and below the speed change operating shaft, and an engaging member that is selectively engaged by a speed change lever is provided at a case outward projecting portion of the speed changing operation shaft. Forming the portion, and connecting and fixing the check member to the case outward projecting portion of the clutch operating shaft in a state of extending upward from the clutch operating shaft,
When the clutch operating shaft is rotated to the clutch engagement position, the upper end portion of the restraining member swings forward to perform the reverse shift, and the engaging portion of the engaging member of the speed change operating shaft shifts in the shift shift direction. A shift operation structure for a walk-type working machine , wherein the shift operation shaft is engaged from the rear side intersecting with the shaft to prevent the shift operation shaft from shifting to a reverse position . The shift of the walking type work machine according to claim 1 , wherein the engagement member is formed on the engagement member such that a rear end of the engagement portion is located on a rear side of an axis of the clutch operation shaft. Operation structure. The check member is selectively moved to the upper and lower two positions and fastened and fixed to the clutch operating shaft with a bolt, so that the attachment position of the check member can be changed between a lower check release position and an upper check production position. The speed change operation structure of the walking type working machine according to claim 1 or 2 . 4. A walking work machine according to claim 3, wherein a long dharma hole is formed in the restraining member in the vertical direction, and a circular positioning seat portion is formed in the head of the bolt to be fitted in the upper and lower hole portions of the dharma hole. Shifting operation structure.

Images