JP5038342B2 - Working machine - Google Patents

Description

  The present invention relates to a work machine including a transmission case that branches and transmits power input from an engine side to a propulsion shaft for traveling and an external power output shaft.

As described above, as a work machine in which a plurality of power take-out portions including a propulsion shaft for traveling and an external power output shaft are provided in a transmission case, those having structures shown in the following [1] and [2] have been conventionally known. Yes.
[1] A plurality of shift gears that rotate integrally with the input shaft are pivotally attached to the input shaft to the transmission case, and the power is sequentially transmitted from each shift gear to the transmission gear that is supported by the transmission shaft at the subsequent stage, The power transmission is transmitted from the final transmission shaft of the travel system transmission mechanism to the travel propulsion shaft, and the power is transmitted from the final transmission shaft of the work transmission mechanism to the external power output shaft (see Patent Document 1).
[2] A plurality of shift gears are distributed and mounted on an input shaft to the transmission case and a transmission shaft at a position adjacent to the input shaft, and are pivotally supported by the transmission shaft at the adjacent position from the shift gear on the input shaft side. The power is sequentially transmitted to the lower gears through the other shift gear or without the shift gear pivotally supported by the transmission shaft at the adjacent position, and the travel propulsion shaft is transmitted from the last transmission shaft of the traveling system transmission mechanism. The power is transmitted to the external power output shaft from the final transmission shaft of the work system transmission mechanism (see Patent Document 2).

JP-A-8-58405 (paragraphs [0009], [0010], FIGS. 4 and 6) JP 2008-167666 A (paragraphs [0031], [0032], FIG. 6, FIG. 8, FIG. 9)

In the prior art having the structure shown in [1] above, a plurality of shift gears are arranged on one input shaft. Therefore, in order to ensure the left-right width and the left-right movement area of the plurality of shift gears, The width in the left-right direction of the case becomes considerably large. For this reason, as a small working machine, there are problems such as being difficult to handle in a narrow place or being heavy and difficult to operate.
Further, in the prior art having the structure shown in [2], a plurality of shift gears are distributed and arranged on a plurality of transmission shafts, which is advantageous in that the problem as in [1] can be avoided. However, even in this structure, power transmission to the travel propulsion shaft and the external power output shaft is performed in each of the final transmission shaft of the travel transmission mechanism and the final transmission shaft of the work transmission mechanism. Each is transmitted from a separate axis.
For this reason, the gears for speed change provided on the transmission shaft of each final stage tend to be subject to placement restrictions depending on the positions of the sprockets for branch transmission, and design restrictions are imposed on the structure of the speed change mechanism. It was easy to receive.

  The object of the present invention is to devise a transmission structure in the transmission system of the traveling system transmission mechanism and the work system transmission mechanism arranged in the mission case, work that can reduce the number of parts and miniaturize the transmission case Is to provide a machine

[Solution 1]
Technical means taken in the present invention in order to solve the above problems, an input shaft to which power from the engine side is transmitted, traveling system transmission mechanism for transmitting the power transmitted to the input shaft to the traveling propelling shaft And a work system in which the work system transmission mechanism for transmitting to the external power output shaft is built in the transmission case,
A single branch transmission shaft for branching and transmitting the power transmitted to the input shaft to the traveling propulsion shaft and the external power output shaft in the middle of the transmission system of the traveling system transmission mechanism and the working system transmission mechanism And branching the traveling transmission mechanism and the working transmission mechanism on the lower transmission side of the single branch transmission shaft,
On the transmission upper side than the branch transmission shaft, the traveling system transmission mechanism and the work system transmission mechanism are configured by a speed change mechanism that shifts the power transmitted to the input shaft in multiple stages,
The transmission mechanism includes a plurality of shift gears each including a part of the total number of shift stages and a plurality of transmission shafts that individually support the plurality of shift gears, and the shift gears are engaged with each other. The power transmission between the transmission shafts is performed.

[Action and effect]
As described above, in the working machine of the present invention according to the solution 1, the power transmitted to the input shaft is transmitted to the traveling propulsion shaft and the external part of the transmission system between the traveling system transmission mechanism and the working system transmission mechanism. Since a single branch transmission shaft for branch transmission to the power output shaft is provided, and the traveling system transmission mechanism and the work system transmission mechanism are branched on the lower transmission side than the single branch transmission shaft, The traveling transmission mechanism and the working transmission mechanism closer to the transmission side than the single branch transmission shaft can be disposed close to each other.
For this reason, instead of branching from a single branch transmission shaft on the lower side of the transmission than the input shaft as described above, for example, the power input to the input shaft is immediately branched to the traveling system transmission mechanism and the work system transmission mechanism. Compared to the structure, the transmission mechanisms are more easily arranged closer to each other on the transmission upper side than the branch transmission shaft. Therefore, when a transmission mechanism is incorporated in these transmission mechanisms, one of the transmission mechanisms close to each other is arranged. It becomes easy to configure so that the portion can be shared by the components of the speed change mechanism.
Accordingly, for example, the power input to the input shaft is immediately branched into the traveling system transmission mechanism and the working system transmission mechanism, and independent transmission mechanisms are provided for each of the traveling system transmission mechanism and the working system transmission mechanism. Compared to the structure as described above, there is an advantage that the structure can be easily simplified.

[Solution 2]
The second solving means of the working machine in the present invention, transmission element such as various gears for transmitting power taken from the input shaft to the transmission downstream side is inputted to one side in the axial direction of the transmission shaft A transmission element that transmits power from the transmission upper side to the transmission shaft on the lower transmission side from a position closer to the other side in the axial direction, and from the transmission upper side input to the other side in the axial direction of each transmission shaft The transmission power is provided in a state of being mixed with transmission elements that transmit the power of the power from the position closer to the one side in the axial direction to each transmission shaft on the lower transmission side.

[Action and effect]
In the working machine of the present invention according to the above solution 2, transmission elements such as various gears that transmit the power taken in from the input shaft to the lower transmission side are input to one side in the axial direction of each transmission shaft. The power from the upper transmission side is not simply configured to be transmitted from the position on the other side in the axial direction to the transmission shaft on the lower transmission side. Transmission elements that transmit the power from the upper transmission side input to the other side in the axial direction of each transmission shaft to the transmission shafts on the lower transmission side from a position closer to the one side in the axial direction are mixed. It is provided in the state.
Therefore, the arrangement of the transmission elements is such that the power from the transmission upper side input to one side in the axial direction of each transmission shaft is transmitted from the position closer to the other side in the axial direction to the transmission shaft on the lower transmission side. As compared with the case where the transmission case is constituted only by the above, it is possible to suppress an increase in the lateral width of the transmission case which is the axial direction of each transmission shaft.

[Solution 3]
The third solving means of the working machine in the present invention, among the plurality of shift shaft for supporting the sheet Futogiya to each other, constituted by the axis without rotating a portion of the transmission shaft, the transmission shaft without this rotation, the axial direction A shift gear that is relatively movable and relatively rotatable is pivotally supported.

[Action and effect]
In the working machine of the present invention according to the above solution 3, a shift gear that is relatively movable and relatively rotatable in the axial direction, which does not need to be rotated integrally with the transmission shaft, is used as a part of the plurality of transmission shafts. The part of the transmission shaft is configured by a non-rotating transmission shaft that is pivotally supported by a shaft. For this reason, the bearing portion of the non-rotating transmission shaft does not require a ball bearing for rotationally supporting the transmission shaft.

  Therefore, the ball bearing for supporting the non-rotating transmission shaft can be omitted, the number of parts can be reduced, and it can be placed close to other transmission shafts without being restricted by the size of the ball bearing. Therefore, there is an advantage that the transmission mechanism can be reduced in size, and the transmission case accommodating the transmission mechanism can be reduced in size and weight.

[Solution 4]
In the fourth solving means in the working machine of the present invention, the shift gear is pivotally supported to the gear shaft, not rotating, the outer peripheral edge, to another transmission shaft with the shift gear and occlusal to shift gear, the It is arranged to be closer to the outer peripheral surface of the another transmission shaft than the outer peripheral edge of the bearing for bearing the other transmission shaft.

[Action and effect]
In the working machine of the present invention according to Solution 4 configured as described above, the outer peripheral edge of the shift gear pivotally supported by the non-rotating transmission shaft is connected to another transmission shaft having a shift gear meshing with the shift gear. The outer peripheral surface of the bearing that receives the other transmission shaft is brought closer to the outer peripheral surface of the other transmission shaft.
As a result, it is possible to arrange the non-rotating transmission shaft in a state of being very close to other transmission shafts, and to reduce the size of the transmission mechanism, the size of the transmission case that houses the transmission mechanism, and the weight reduction. There is an advantage that can be further improved.

Overall side view of work equipment Diagram showing the mode of operation of the transmission in the mission case Side view showing the inside of the mission case Development view showing the power transmission structure in the mission case Development view showing the power transmission structure in the mission case A development view showing a shift mechanism for shifting, Explanatory drawing which shows the lever guide part of the shift mechanism for gear shifting Sectional view showing differential operation mechanism Sectional view showing part of differential operation mechanism

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Walking work machine overall configuration]
FIG. 1 is an overall side view showing a walking type tiller as an example of a walking type working machine according to the present invention.
As shown in this figure, the walking type tiller includes a steering handle 12 on the rear side of the body frame 10 on which the engine 11 is mounted, and a pair of right and left driveable tire-type traveling wheels 13 that support the body frame 10. , 13 and a rotary tiller 2 connected to the rear side of the body frame 10 of the self-propelled body 1.

  The fuselage frame 10 includes a mission case 3 that supports the pair of left and right axles 13a and 13a, and an engine support frame 10A that extends forward from the mission case 3 toward the front of the fuselage.

The steering handle 12 extends from the handle support portion 3 a provided at the outer periphery of the case on the rear side of the mission case 3 toward the rear upper side of the self-propelled aircraft 1.
The steering handle 12 includes a traveling clutch lever 15 and an accelerator operating tool 16 for turning on and off a main clutch 14 for intermittently connecting / disconnecting power from the engine 11 to a transmission device in the transmission case 3, and A steering operation tool such as a brake operation tool is provided.

  As shown in FIG. 1, the rotary tiller 2 includes a rotary drive shaft (an example of an external power output shaft) 20 provided on the rear side of the mission case 3 and a rotary drive attached to the rotary drive shaft 20. In addition to the tilling rotor 21 and the grounding resistance rod 22, a tilling rotor cover 23 that covers the top of the tilling rotor 21 and a leveling plate 24 are provided.

[Configuration of power transmission system]
The configuration of the power transmission system when the power from the engine 11 is transmitted to the axles 13a and 13a as the traveling propulsion shaft and the rotary drive shaft 20 as the external power output shaft will be described.

The main clutch 14 constituted by a belt transmission mechanism is provided across an output pulley 11b provided on the output shaft 11a of the engine 11 shown in FIGS. 1 and 2 and an input pulley 30a provided on the input shaft 30 of the transmission case 3. It is.
The main clutch 14 includes a transmission belt 14a wound around the output pulley 11b and the input pulley 30a, and a tension pulley 14b that can be switched between a tension state and a relaxation state of the transmission belt 14a. Yes. Since the tension pulley 14b is linked to the traveling clutch lever 15 provided on the steering handle 12, the main clutch 14 is brought into the engaged state in accordance with the operation of the traveling clutch lever 15 provided on the steering handle 12. Switching operation can be performed to the cut-off state.

  As shown in FIG. 3, in the transmission case 3, an input shaft 30 to which power from the engine 11 is transmitted is formed in the upper part of the case, the axles 13 a and 13 a as travel propulsion shafts, and an external power output shaft. The rotary drive shaft 20 is disposed at the lower part of the case so as to be separated from the front and rear. In addition to this, in the transmission case 3, there are arranged transmission shafts of a first transmission shaft 31, a second transmission shaft 32, and a third transmission shaft (corresponding to a branch transmission shaft described later) 33. Each of them is arranged to transmit power by supporting a transmission gear or a transmission chain, which will be described later.

Further, in this mission case 3, as shown in FIGS. 3 to 7, a second shift operating mechanism S2 for operating a second shift gear 50 slidably fitted on the input shaft 30, and A first shift operation mechanism S1 for operating a first shift gear 40 slidably fitted on the first transmission shaft 31 is provided.
The first shift operation mechanism S1 for operating the first shift gear 40 and the second shift operation mechanism S2 for operating the second shift gear 50 are configured such that the speed change operation lever 17 shown in FIG. By operating along 18, each can be operated independently.

  Further, in the transmission case 3, as shown in FIGS. 3 and 8, the differential mechanism 34 mounted on the pair of left and right axles 13a, 13a, and the differential mechanism 34 in the diff lock state and the diff lock release state A differential operation mechanism 6 for switching between the two is provided.

  As shown in FIGS. 2 and 3, the above transmission device provided in the transmission case 3 includes a pair of left and right axles (an example of a propulsion shaft for traveling) from an input shaft 30 to which power from the engine 11 is transmitted. The travel system transmission mechanism 4 up to 13a and 13a and the work system transmission mechanism 5 from the input shaft 30 to the rotary drive shaft (an example of an external output shaft) are configured.

[Running transmission mechanism]
The traveling system transmission mechanism 4 is configured as follows.
That is, as shown in FIGS. 2 to 6, the traveling transmission mechanism 4 has one end on the right side in FIG. 4 of the second shift gear 50 that is spline engaged with the input shaft 30 so as to be freely slidable and integrally rotated. A small-width gear 50a formed on the side, a wide-width gear 50b formed on the left end side of the second shift gear 50, and a first transmission shaft 31 that is relatively fitted and freely slidable. The first shift gear 40, the large-diameter gear 41 fixed to the second transmission shaft 32, the wide small-diameter gear 42 integrally formed on the left end side of the second transmission shaft 32 in FIG. A constant-meshing large-diameter gear 43 fixed to the third transmission shaft 33 in a state of constant engagement with the small-diameter gear 42, a traveling system output sprocket 44 formed integrally with the third transmission shaft 33, and an axle 13a integrally fixed. The traveling system input sprocket 46 and the traveling system output sprocket It is constituted by a transmission chain 45 stretched between the 44 and the traveling system input sprocket 46.

  In the traveling system transmission mechanism 4, the power transmission state from the input shaft 30 to the axle 13a can be switched to the following four types [1] to [4].

[1]: Running stop state As shown in FIG. 4 and FIG. 5, the second shift gear 50 is neutral so that the small gear 50 a and the wide gear 50 b do not mesh with the large gear 41 fixed to the second transmission shaft 32. Position to position “N”. The first shift gear 40 is positioned at a neutral position “N” that does not mesh with either the large-diameter gear 41 fixed to the second transmission shaft 32 or the constant-mesh large-diameter gear 43 fixed to the third transmission shaft 33. .
As a result, transmission of power to the lower transmission side of the second shift gear 50 and the first shift gear 40 is cut off, resulting in a travel stop state in which the axle 13a is not driven.

[2]: Forward first speed traveling state The small width gear 50a formed on the second shift gear 50 is moved to the forward first speed position “F1” on the left side in FIG. 4 and fixed to the second transmission shaft 32. The large gear 41 is engaged. The first shift gear 40 is positioned at a neutral position “N” that does not mesh with either the large-diameter gear 41 fixed to the second transmission shaft 32 or the constant-mesh large-diameter gear 43 fixed to the third transmission shaft 33. .
As a result, the power of the input shaft 30 is changed from the input shaft 30 → the second shift gear 50 → the large diameter gear 41 → the wide small diameter gear 42 → the fixed constant biting large diameter gear 43 → the traveling system output sprocket 44 → the transmission chain 45 → the traveling system. Input sprocket 46 → axle 13a is transmitted, and a forward first speed traveling state is set.

[3]: Forward second speed traveling state As shown in FIG. 4, the second shift gear 50 is positioned at a neutral position where the small gear 50 a and the wide gear 50 b do not mesh with the large gear 41 fixed to the second transmission shaft 32. N ”. The first shift gear 40 is moved to the left in FIG. 5 and is positioned at the forward second speed position “F2” that meshes with the normally meshed large-diameter gear 43 fixed to the third transmission shaft 33.
As a result, the power of the input shaft 30 is changed from the input shaft 30 → the second shift gear 50 → the first shift gear 40 → the stationary constant bite large diameter gear 43 → the traveling system output sprocket 44 → the transmission chain 45 → the traveling system input sprocket 46 → the axle 13a. It will be transmitted and it will be in the 2nd forward traveling state.

[4]: Reverse first speed traveling state As shown in FIG. 4, the second shift gear 50 is set at a neutral position “where the small gear 50 a and the wide gear 50 b do not mesh with the large gear 41 fixed to the second transmission shaft 32. N ”. The first shift gear 40 is moved to the right in FIG. 5 and is positioned at the reverse first speed position “R1” that meshes with the large-diameter gear 41 fixed to the second transmission shaft 32.
As a result, the power of the input shaft 30 is changed from the input shaft 30 → the second shift gear 50 → the first shift gear 40 → the large diameter gear 41 → the wide small diameter gear 42 → the stationary constant biting large diameter gear 43 → the traveling system output sprocket 44 → transmission. The chain 45 → traveling system input sprocket 46 → axle 13a is transmitted, and the vehicle enters the reverse 1-speed traveling state.

[Work system transmission mechanism]
The work system transmission mechanism 5 is configured as follows.
That is, as shown in FIGS. 2 to 6, the working transmission mechanism 5 has one end side on the right side in FIG. 4 of the second shift gear 50 that is fitted on the input shaft 30 so as to be slidable and integrally rotated. A wide gear 50b formed on the left end side in the figure, a wide first gear 51 externally fitted to the first transmission shaft 31 so as to allow only relative rotation, A large-diameter second gear 52 externally fitted only to the second transmission shaft 32 so as to allow only relative rotation; a small-diameter third gear 53 formed so as to rotate integrally with the large-diameter second gear 52; A normally-engaged fourth gear 54 that is externally fitted to the third transmission shaft 33 so as to be only rotatable relative to the third gear 53 in a constantly meshed state, and a work system output formed integrally with the normally-meshed fourth gear 54. Work system input sprocket 5 fixed integrally with the sprocket 55 and the rotary drive shaft 20 When it is configured by a transmission chain 56 stretched between the working system input sprocket 57 and the working-system output sprocket 55.

  In this work system transmission mechanism 5, the power transmission state from the input shaft 30 to the rotary drive shaft 20 can be switched to the following three types [1] to [3].

[1]: Tillage stop state As shown in FIGS. 4 and 5, the second shift gear 50 is neutral so that the small gear 50 a and the wide gear 50 b do not mesh with the large gear 41 fixed to the second transmission shaft 32. Position to position “N”. The first shift gear 40 is positioned at a neutral position “N” that does not mesh with either the large-diameter gear 41 fixed to the second transmission shaft 32 or the constant-mesh large-diameter gear 43 fixed to the third transmission shaft 33. .
As a result, the power transmission to the lower transmission side of the second shift gear 50 and the first shift gear 40 is cut off, so that the tillage stop state in which the rotary drive shaft 20 is not driven is achieved. At this time, the wide first gear 51 of the first transmission shaft 31 is normally meshed with the large-diameter second gear 52 of the second transmission shaft 32, but the first gear 51 and the first shift gear 40 are both Since the first transmission shaft 31 is provided so as to be rotatable relative to the first transmission shaft 31, no power is transmitted.

[2]: Forward rotation state The small gear 50a formed on the second shift gear 50 is moved to the right forward rotation position “positive” in FIG. The gear is engaged with the forward rotation tooth portion 52a of the supported large-diameter second gear 52. At this time, the wide gear 50 b of the second shift gear 50 meshes with the large-diameter gear 41 fixed to the second transmission shaft 32. The first shift gear 40 is positioned at a neutral position “N” that does not mesh with either the large-diameter gear 41 fixed to the second transmission shaft 32 or the constant-mesh large-diameter gear 43 fixed to the third transmission shaft 33. .
As a result, the power of the input shaft 30 is the power of the input shaft 30 → the second shift gear 50 → the large second gear 52 → the small third gear 53 → the constantly-engaged fourth gear 54 → the traveling system output. Sprocket 55 → transmission chain 56 → travel system input sprocket 57 → rotary drive shaft 20 is transmitted, and the forward drive state is established.
At this time, the large-diameter second gear 52 of the second transmission shaft 32 has a linkage tooth portion 52b that is normally meshed with the wide first gear 51 of the first transmission shaft 31. Since both 51 and the first shift gear 40 are mounted so as to be rotatable relative to the first transmission shaft 31, no power is received from the first gear 51.
Then, the power of the input shaft 30 is also transmitted to the traveling drive system, and as in the case of the first forward speed, the input shaft 30 → the second shift gear 50 → the large diameter gear 41 → the wide small diameter gear 42 → the fixed constant. The meshed large-diameter gear 43 → the traveling system output sprocket 44 → the transmission chain 45 → the traveling system input sprocket 46 → the axle 13a is transmitted, and a forward first speed traveling state is established.

[3]: Reverse drive state The small-width gear 50a formed on the second shift gear 50 is moved to the reverse rotation position "reverse" further to the right in FIG. The wide first gear 51 is engaged. At this time, the wide gear 50 b of the second shift gear 50 meshes with the large-diameter gear 41 fixed to the second transmission shaft 32. The first shift gear 40 is positioned at a neutral position “N” that does not mesh with either the large-diameter gear 41 fixed to the second transmission shaft 32 or the constant-mesh large-diameter gear 43 fixed to the third transmission shaft 33. .
As a result, the power of the input shaft 30 is the power of the input shaft 30 → the second shift gear 50 → the wide first gear 51 → the large diameter second gear 52 → the small diameter third gear 53 → the constant bite in the tillage work system. 4 gears 54 → traveling system output sprocket 55 → transmission chain 56 → traveling system input sprocket 57 → rotary drive shaft 20 and the reverse drive state is established.
At this time, the power of the input shaft 30 is also transmitted to the traveling drive system, and the input shaft 30 → the second shift gear 50 → the large gear 41 → the wide small gear 42 → fixed as in the case of the first forward speed. The constant-gear large-diameter gear 43 → the traveling system output sprocket 44 → the transmission chain 45 → the traveling system input sprocket 46 → the axle 13a is transmitted, and a forward first speed traveling state is established.

[Shift operation mechanism]
The first shift operation mechanism S1 for operating the first shift gear 40 and the second shift operation mechanism S2 for operating the second shift gear 50 are configured as shown in FIGS.
That is, the first shift operation mechanism S1 includes a first shift fork 36 that engages with an intermediate position in the length direction of the first shift gear 40, a first shift rod 36A that includes the first shift fork 36 at its shaft end, The detent mechanism 38 is configured to stably maintain the operation position of the first shift rod 36A.
The detent mechanism 38 includes a positioning recess 38a formed on the outer surface of the first shift rod 36A, and a steel ball 38b elastically biased so as to be pressed against the positioning recess 38a by a coil spring 38c. Has been. The positioning recesses 38a are respectively provided corresponding to the forward second speed position “F2”, the neutral position “N”, and the reverse first speed position “R1”. It is possible to stably position at each position.

The second shift operating mechanism S2 includes a second shift fork 37 that engages with one end in the length direction of the second shift gear 50, a second shift rod 37A that includes the second shift fork 37 at the shaft end, The detent mechanism 38 for stably maintaining the operation position of the 2 shift rod 37A.
The detent mechanism 38 includes a positioning recess 38a formed on the outer surface of the second shift rod 37A, and a steel ball 38b elastically biased so as to be pressed against the positioning recess 38a by a coil spring 38c. Has been. The positioning recesses 38a are respectively provided corresponding to the first forward speed position “F1”, the neutral position “N”, the forward drive position “forward”, and the reverse drive position “reverse”. The second shift gear 50 can be stably positioned at each of these positions.

  FIG. 7 shows a lever guide 18 with a guide groove for guiding the operation of the shift lever 17. In the figure, the shift operation by the second shift operation mechanism S2 is performed by lever operation along the upper guide groove. A shift operation by the first shift operation mechanism S1 is performed by a lever operation along the lower guide groove.

[Transmission mechanism]
The traveling system transmission mechanism 4 and the working system transmission mechanism 5 configured as described above are mutually connected in the transmission system path from the input shaft 30 to the third transmission shaft 33 that is a branch transmission shaft. The component is configured to overlap the component of the other transmission mechanism, and the components for transmission are independent from each other on the lower transmission side than the third transmission shaft 33 that is a branch transmission shaft. In order to be a structure, it is configured as a branched transmission structure.

In the transmission path from the input shaft 30 to the third transmission shaft 33 that is a branch transmission shaft, as described above, the gears that are components for the transmission and the gears are supported. The arrangement structure including the respective transmission shafts shifts the power transmitted to the input shaft 30 in multiple stages and transmits it to the axle 13a and the rotary drive shaft 20 on the output side of the traveling system transmission mechanism 4 and the working system transmission mechanism 5. It also plays a role as a speed change mechanism.
Further, since the first shift gear 40 and the second shift gear 50 used in the transmission mechanism are also used in mesh with each other, they also function as a part of the transmission mechanism that transmits power.

As shown in FIGS. 4 to 6, the second shift gear 50 mounted on the input shaft 30, the first shift gear 40 for revealing all the shift stages by the speed change mechanism, and the wide first gear 51 are The first transmission shaft 31 is supported so as to be relatively rotatable via a needle bearing.
The first shift gear 40 is provided with an engagement recess formed of an annular groove with which the first shift fork 36 is engaged at an intermediate position in the sliding direction. The first shift gear 40 allows rotation of the shift gear 40 and the first transmission shaft 31. It is configured to be slidable in the axial direction.

As shown in FIGS. 4 to 6, the first transmission shaft 31 that pivotally supports the first shift gear 40 is supported by a bearing recess 3 d formed on the inner wall surface of the transmission case 3 with respect to the transmission case 3. Has been. And the step part 31a by which the axial outer peripheral part was partly cut off was provided in one axial end of the 1st transmission shaft 31, and the state which prevented the 1st transmission shaft 31 from rotating with respect to the transmission case 3 It is mounted so as not to rotate.
As a result, the outer peripheral edge of the first shift gear 40 supported by the non-rotating first transmission shaft 31 and the wide first gear 51 is more input than the outer peripheral edge of the ball bearing 30b that supports the input shaft 30. It is in the state arrange | positioned so that the outer peripheral surface of this may be approached.

[Differential operation mechanism]
As shown in FIGS. 3 and 8, a differential mechanism is provided in the transmission case 3 so that the relative rotation of a pair of left and right axles (an example of a propulsion shaft for traveling) 13a and 13a can be regulated and deregulated. There is provided a differential operation mechanism 6 capable of switching 34 between a differential lock state and a lock release state.
The differential operation mechanism 6 is in a state of passing through a shifter 60 for pushing and pulling the differential lock claw body 35 provided in the differential mechanism 34 in the axial direction of the axle 13a, and a boss portion 60A of the shifter 60. The operation shaft 61 is supported, and the cam mechanism 62 converts the rotational movement of the operation shaft 61 into a push-pull operation of the shifter 60.

The cam mechanism 62 includes a pin 62a projecting in the radial direction of the operation shaft 61 from the outer peripheral surface of the operation shaft 61, and an inclined cam surface formed on the boss 60A of the shifter 60 so as to be in sliding contact with the pin 62a. 62b. The shifter 60 is always elastically biased toward the unlocking side by a coil spring 63 provided on the outer peripheral side of the operation shaft 61.
Therefore, the pin 62a of the operation shaft 61 is formed on the boss portion 60A of the shifter 60 by rotating the operation lever 61A provided on one end side of the operation shaft 61 protruding outside the mission case 3 in one direction. The differential mechanism 34 can be brought into the differential lock state by contacting the inclined cam surface 62b and pushing the shifter 60 leftward in FIG. 8 to engage the differential lock claw body 35.
When the operation lever 61A is rotated in the reverse direction, the shifter 60 is pushed by the coil spring 63 and moves to the right in FIG. 8, and the engagement of the differential lock claw body 35 is released, and the differential mechanism 34 is moved. The diff lock can be released.
Although the operation lever 61A is not shown in the drawing, the operation lever 61A is provided with means for maintaining the operation position of the operation tool by linking the operation tool provided at an appropriate position of the steering handle 12 with an operation wire or the like. The operation state can be maintained.

As shown in FIG. 8, an annular rib 64 having a diameter larger than that of the boss portion 60 </ b> A of the shifter 60 is provided on the inner surface side of one divided case unit 3 </ b> A of the transmission case 3 around the outer peripheral side of the operation shaft 61. Is formed.
The annular rib 64 serves as a reinforcing member for the projecting portion of the case lower edge 3c of the mission case 3, and surrounds the outer peripheral side of the cam mechanism 62 to lubricate the cam mechanism 62. The oil is easily secured.

  Further, as shown in FIG. 9, the guide protrusion 64a is inserted into the recess 60B formed by providing the inclined cam surface 62b on the boss 60A of the shifter 60 on the inner peripheral surface side of the annular rib 64. Is formed. The guide protrusion 64a is configured such that when the operation shaft 61 is rotated and the pin 62a comes into contact with the inclined cam surface 62b to push the shifter 60 toward the differential lock side, the boss portion 60A of the shifter 60 is provided. The boss portion 60A functions so as to prevent the rotation of the boss portion 60A. Therefore, the differential lock claw body 35 can be easily operated smoothly without applying unnecessary rotational operation force to the shifter 60, and is also useful as a guide means when returning the shifter 60 to the original posture when the differential lock is released.

  Although the annular rib portion having a large diameter is not provided on the other divided case unit 3B side as in the case of the annular rib 64, the bearing portion 3d for supporting the other end side of the operation shaft 61 is provided in the divided case. It also serves as an annular rib that helps to improve the strength of the bent portion of the case lower edge 3c on the unit body 3B side.

[Mission case]
The mission case 3 is configured by combining a pair of left and right divided case units 3A and 3B, and is an axle 13a that is the propulsion shaft for driving and an external power output shaft in a side view as shown in FIG. The rotary drive shaft 20 is formed long in the front-rear direction so as to be separated from the front-rear position and positioned on the lower end side.
A third transmission shaft 33 is provided at an intermediate portion of the axle 13a and the rotary drive shaft 20 in the front-rear direction. This third transmission shaft 33 branches and transmits the power transmitted to the input shaft 30 to the axle 13a and the rotary drive shaft 20 in the middle of the transmission system of the traveling system transmission mechanism 4 and the work system transmission mechanism 5. It corresponds to a single branch transmission shaft.

The transmission case 3 is bent and formed in a shape in which the case upper edge 3b side and the case lower edge 3c side above the third transmission shaft 33, which is the branch transmission shaft, are both bent upward.
The axle 13a is located below the third transmission shaft 33, which is a branching point between the transmission system to the axle 13a and the transmission system to the rotary drive shaft 20, on the side of the case lower edge 3c. An operation shaft 61 of the differential operation mechanism 6 is provided outside the rotation range of the transmission chain 45 that transmits the driving force to the differential operation mechanism 6. Therefore, it is not necessary to provide a space for providing the operation shaft 61 of the differential operation mechanism 6 inside the rotation range of the transmission chain 45.

In this transmission case 3, the transmission elements such as various gears for transmitting the power taken in from the input shaft 30 are transmitted to the one side in the axial direction of the respective transmission shafts 31, 32, 33. A transmission element for transmitting the power from the side to the transmission shafts 31, 32, 33 on the lower transmission side from a position closer to the other side in the axial direction, and the other in the axial direction of the transmission shafts 31, 32, 33 The power from the transmission upper side input to the side is provided in a state of being mixed with transmission elements that transmit power from the position closer to the one side in the axial direction to the transmission shafts 31, 32, 33 on the lower transmission side. Yes.
Therefore, for example, in the transmission shafts 31, 32, and 33 on the upper transmission side, even if each transmission element is disposed on the side where the input pulley 30a exists in the left and right direction, the transmission shafts 31, 32, and 33 in the rear stage Then, each transmission element is conversely arranged near the side where the input pulley 30a exists, so that an unnecessary increase in the lateral thickness of the mission case 3 is limited.

  Further, the transmission chain 45 that transmits the driving force to the axle 13a and the transmission chain 56 that transmits the driving force to the rotary drive shaft 20 include a third transmission shaft that is a single branch transmission shaft, and a transmission chain that transmits more than that. It is arranged at a lower position equivalent to or lower than the transmission shafts 30, 31, 32 on the upper side. As a result, the transmission chains 45 and 56 can be arranged by passing under the transmission shafts 30, 31 and 32 on the upper side, and the transmission shafts 30, 31 and 32 on the upper side in plan view. It can arrange | position in the state which overlaps with the location. This also has the advantage that the thickness of the mission case 3 in the left-right direction can be reduced.

[Other Embodiment 1]
The travel propulsion shaft does not need to be the axle 13a as in the above embodiment. For example, when a small rubber crawler is used without using the wheels 13, the drive sprocket is driven directly or indirectly. It may be.

[Second embodiment]
The external power output shaft does not need to be the rotary drive shaft 20 as in the above-described embodiment, and may be any shaft for outputting the drive force according to the type of work device used.

  The working machine in the present invention is not limited to a walking type tiller, but can be applied to a vegetable transplanting machine, a walking type rice transplanter, or the like.

2 Rotary tillage device 3 Mission case 4 Traveling system transmission mechanism 5 Working system transmission mechanism 11 Engine 13a Axle (propulsion shaft for traveling)
20 Rotary drive shaft (external power output shaft)
30 Input shaft 30b Ball bearing 31 First transmission shaft 32 Second transmission shaft 33 Third transmission shaft (branch transmission shaft)
40 First shift gear 50 Second shift gear

Claims (3)

The transmission case includes an input shaft for transmitting power from the engine side, a traveling system transmission mechanism for transmitting the power transmitted to the input shaft to the traveling propulsion shaft, and a working system transmission mechanism for transmitting to the external power output shaft. Is a working machine built in
A single branch transmission shaft for branching and transmitting the power transmitted to the input shaft to the traveling propulsion shaft and the external power output shaft in the middle of the transmission system of the traveling system transmission mechanism and the working system transmission mechanism And branching the traveling transmission mechanism and the working transmission mechanism on the lower transmission side of the single branch transmission shaft,
On the transmission upper side than the branch transmission shaft, the traveling system transmission mechanism and the work system transmission mechanism are configured by a speed change mechanism that shifts the power transmitted to the input shaft in multiple stages,
The transmission mechanism includes a plurality of shift gears each including a part of the total number of shift stages and a plurality of transmission shafts that individually support the plurality of shift gears, and the shift gears are engaged with each other. Configured to transmit power between the transmission shafts ,
The transmission elements such as various gears that transmit the power taken in from the input shaft to the lower transmission side, the power from the upper transmission side input to one side in the axial direction of each transmission shaft, the other in the axial direction The transmission element that transmits to the transmission shaft on the lower transmission side from the position closer to the transmission side, and the power from the transmission upper side that is input to the other side in the axial direction of each transmission shaft, the power closer to the one side in the axial direction. A working machine characterized in that it is provided in a state where transmission elements that transmit from the position to each transmission shaft on the lower transmission side are mixed . Among the plurality of transmission shafts that support the shift gears separately, some of the transmission shafts are configured as non-rotating shafts, and the non-rotating transmission shaft is pivotally supported with a shift gear that is relatively movable in the axial direction and relatively rotatable. The working machine according to claim 1, wherein   The shift gear pivotally supported by the non-rotating transmission shaft has an outer periphery that is different from an outer periphery of a bearing that supports the other transmission shaft with respect to another transmission shaft that includes the shift gear meshing with the shift gear. The work machine according to claim 2, wherein the work machine is disposed so as to approach an outer peripheral surface of the another transmission shaft.

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