JP2870698B2 - Work vehicle transmission structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power transmission structure of a working vehicle provided with a belt-type continuously variable transmission.

2. Description of the Related Art There is a belt-type continuously variable transmission used in a work vehicle in which an upper pulley and a lower pulley are configured in a split pulley type including a fixed pulley piece and a movable pulley piece. By shifting the movable pulley piece of the lower pulley along the transmission shaft, the winding radius of the transmission belt is changed to perform the speed change operation.

[Problems to be Solved by the Invention] In the belt-type continuously variable transmission as described above, the vibration of the engine as well as the power of the engine is transmitted to the transmission shaft on the upstream side that supports the pulley on the upstream side. Further, when the engine is supported by the body frame by vibration isolating rubber or the like, the vibration of the engine is hardly transmitted to the body frame, but the vibration of the engine transmitted to the transmission shaft on the upper side becomes remarkable.

The upper transmission shaft to which the vibration of the engine is transmitted is provided with a split pulley type upper pulley, and the movable pulley piece of the upper pulley is slid along the upper transmission shaft. With this configuration, it is anticipated that rattling will occur at the fitting portion between the transmission shaft on the upper side and the movable pulley piece due to use for a long period of time, and that the rattling will gradually increase due to the vibration of the engine. The slide operation of the movable pulley piece may be hindered.

In a belt-type continuously variable transmission, the tension of the transmission belt is constantly applied to the upper and lower transmission shafts, and the bending moment due to the tension of the transmission belt is constantly applied to the upper and lower transmission shafts. ing. This allows
For the rotating upper and lower transmission shafts, the above-described bending and compression stresses are repeatedly generated due to the bending moment, so that the upper and lower transmission shafts may undergo brittle fracture.

The present invention relates to a power transmission structure for a working vehicle equipped with a belt-type continuously variable transmission, in which a loose portion is generated at a fitting portion between a transmission shaft on the upper side and a movable pulley piece, and an upper side and a lower side. The purpose of the present invention is to prevent the brittle fracture from developing on the transmission shaft.

[Means for Solving the Problems] The feature of the present invention resides in that the transmission structure of the working vehicle as described above is configured as follows.

(1) The upper transmission shaft and the lower transmission shaft in the transmission system are protruded in a cantilever manner toward the same side in the lateral direction of the fuselage, and each of the upper transmission shaft and the lower transmission shaft is divided. A pulley type upper pulley and lower pulley are provided, and a transmission belt is wound around the upper pulley and lower pulley to constitute a belt-type continuously variable transmission, and the upper pulley is connected to the upper transmission shaft. A movable pulley piece that can be slid along the movable pulley piece and a moving operation unit that slides the movable pulley piece along the superior transmission shaft are arranged on the left and right central sides of the body of the superior transmission shaft, and the superior transmission shaft is provided. A fixed pulley piece fixed to the lower transmission shaft is disposed outside the body of the upper transmission shaft, and the lower pulley is slidably operated along the lower transmission shaft. Slide along the axis The moving operation part to be made is arranged outside the machine body of the lower transmission shaft, and the fixed pulley piece fixed to the lower transmission shaft is arranged at the left and right center of the machine body of the lower transmission shaft, A connecting member is connected between the moving operation portion of the transmission shaft and the moving operation portion of the lower transmission shaft, and the movable pulley pieces of the upper and lower transmission shafts are moved at a low speed by the linking member and the moving operation portion. It is configured to be slid to the side and the high-speed side.

(2) An engine and a transmission case are arranged at the front of the fuselage so that the engine is positioned in front of the transmission case, and the transmission shaft is arranged at the front side of the fuselage. The lower transmission shaft, which is the lower side, is protruded in a cantilever manner toward the same side in the lateral direction of the body, and the upper and lower transmission shafts are respectively attached to the upper and lower transmission shafts. A movable pulley piece having a pulley, and a belt-type continuously variable transmission configured by winding a transmission belt over the upper and lower pulleys, and being slidable along the upper transmission shaft in the upper pulley. And, a moving operation unit that slides the movable pulley piece along the good transmission shaft is arranged at the center of the left and right body of the good transmission shaft, and the fixed pulley piece fixed to the good transmission shaft is Of the transmission shaft on the better side In the lower pulley, a movable pulley piece slidable along the lower transmission shaft and a moving operation unit that slides the movable pulley piece along the lower transmission shaft are disposed on the lower pulley. The fixed pulley piece, which is located outside the transmission shaft and fixed to the lower transmission shaft, is located at the center of the lower transmission shaft on the left and right sides of the fuselage. The movable member of the upper and lower transmission shafts is slid to the low speed side and the high speed side by connecting the link member to the moving operation portion of the transmission shaft. It is configured in.

[Operation] (i) In the belt-type continuously variable transmission (A) according to the feature of the first aspect, as shown in FIG. 2, for example, as shown in FIG. (Same side as the shaft (2a)), so that when the vibration of the engine is transmitted to the upper transmission shaft (1a), the upper transmission shaft (1a) It is considered that the vibration oscillates about the side. Therefore, the transmission shaft (1
In a), it is considered that the amplitude increases as the portion is outside the fuselage, and the amplitude decreases as the portion is closer to the left and right center.

According to the features of claim 1. For example, as shown in FIG.
Upper pulley (11) provided on the upper transmission shaft (1a)
In, the movable pulley piece (11a) is arranged on the left and right center side of the machine body, and the fixed pulley piece (11b) is arranged on the outside of the machine body.

As described above, the movable pulley piece (11a) of the upper pulley (11) is not arranged on the outer side of the fuselage, which has a larger amplitude on the upper transmission shaft (1a). Move the movable pulley piece (11a) to the upper transmission shaft (1
By arranging it on the left and right center sides of the machine, which is the side with the smaller amplitude in a), it is possible to suppress the occurrence of rattling at the fitting portion between the upper transmission shaft (1a) and the movable pulley piece (11a).

(Ii) In the belt-type continuously variable transmission, when the shifting operation is performed by sliding the movable pulley pieces of the upper pulley and the lower pulley, the transmission belt moves in the radial direction along the inclined inner surface of the fixed pulley piece. State. Accordingly, the transmission belt is moved in the axial direction of the upper and lower transmission shafts by an amount corresponding to the inclination of the inner surface of the fixed pulley along with the speed change operation by the movable pulley piece.

According to the features of claim 1. For example, as shown in FIG.
Upper pulley (11) provided on the upper transmission shaft (1a)
In, the movable pulley piece (11a) is arranged on the left and right center side of the machine body, and the fixed pulley piece (11b) is arranged on the outside of the machine body. Conversely, in the lower pulley (12) provided on the lower power transmission shaft (2a), the movable pulley piece (12a) is arranged outside the fuselage, and the fixed pulley piece (12b) is arranged on the left and right center of the fuselage. .

Thereby, according to the feature of claim 1, the movable pulley piece (11a) of the upper pulley (11) is slid to the outside of the body (the fixed pulley piece (11b) side) (the upper pulley (11)).
When the operation of sliding the movable pulley piece (12a) of the lower pulley (12) on the lower side pulley (12), and the movable pulley piece (12a) of the lower side pulley (12) The belt-type continuously variable transmission (A) is shifted to a higher speed side.

Conversely, slide the movable pulley piece (11a) of the upper pulley (11) to the left and right center of the machine (upper pulley (11)).
And the movable pulley piece (12a) of the lower pulley (12) slides to the left and right center side of the fuselage (fixed pulley piece (12b) side). (The winding radius of the power transmission belt (13) is larger at the side pulley (12)),
The belt-type continuously variable transmission (A) is shifted to a lower speed.

(Iii) According to the features of claim 1, as described in (ii) above,
When the belt-type continuously variable transmission is shifted to a high speed side, the transmission belt is entirely moved to the outside of the fuselage, and when the belt-type continuously variable transmission is shifted to a low speed side, the transmission belt is totally moved. It will be in the state of moving to the left and right center side of the aircraft. in this case,
Generally, at high speeds, high rotation and low torque power is transmitted,
In a low-speed state, low-rotation, high-torque power is transmitted, and the higher the torque, the greater the tension of the transmission belt.

As a result, according to the feature of claim 1, the lower the rotation speed and the higher the torque (the greater the tension of the transmission belt), the more the transmission belt moves to the left and right center side of the fuselage as a whole. The moment arm of the bending moment becomes small. Therefore, the above-mentioned bending moment constantly applied to the upper and lower transmission shafts can be made small as a whole, and for the rotating upper and lower transmission shafts, the compression and bending due to the bending moment described above can be performed. The repeated tensile stress can be reduced.

(Iv) According to the feature of claim 1, since the moving operation part of the upper transmission shaft and the moving operation part of the lower transmission shaft are connected by the linking member, one of the moving operations during the shifting operation is performed. The operation of the other moving operation section is not delayed with respect to the operation of the section, and both moving operation sections are operated without delay by the linking member, and the movable pulley piece of the upper pulley and the lower pulley The movable pulley pieces are slid to the low speed side and the high speed side without delay.

(V) In the belt-type continuously variable transmission according to the feature of claim 1, as described in (ii) above, the movable pulley piece of the upper pulley is slid to the side approaching the fixed pulley piece (outside the body). When the movable pulley piece of the lower pulley is slid to the side (outside the machine body) away from the fixed pulley piece, the belt-type continuously variable transmission is shifted to a higher speed. Conversely, the movable pulley piece of the upper pulley is slid to the side away from the fixed pulley piece (the left and right center side of the machine), and the movable pulley piece of the lower pulley approaches the fixed pulley piece (the left and right center side of the machine). When the belt type continuously variable transmission is shifted to a high speed side (low speed side), the transmission is transmitted against the tension of the transmission belt. The movable pulley piece of the upper pulley (lower pulley) is slid to the side approaching the fixed pulley piece so as to spread the belt, while the movable pulley piece of the lower pulley (upper pulley) is fixed. When the sliding operation is performed to the side separated from the pulley piece, the tension of the transmission belt due to the spread of the movable pulley piece of the above-mentioned upper pulley (lower pulley) assists, and the lower pulley (upper side) is assisted. The movable pulley piece of the pulley can be easily slid to the side away from the fixed pulley piece. In other words, when performing the speed change operation of the belt-type continuously variable transmission, in both the high-speed side and the low-speed side, the sliding operation of one movable pulley piece of the upper side puller and the lower side pulley is performed on the upper side and the lower side. This assists the sliding operation of the other movable pulley piece of the pulley.

Therefore, as in the feature of claim 1, the moving operation unit of the upper transmission shaft and the moving operation unit of the lower transmission shaft are connected by the linking member, and one of the moving operation units is operated at the time of the speed change operation. This is advantageous when the other moving operation unit is configured to operate without delay with respect to the operation (see the preceding paragraph (iv)).

Further, when shifting the belt-type continuously variable transmission,
The operation force is the same in both the high-speed side and the low-speed side, and the operation force of one of the high-speed side and the low-speed side is increased, and the operation force of the other side is increased. A situation where the force is reduced does not occur.

(Vi) As described in (i) above, when the vibration of the engine is transmitted to the transmission shaft on the upper side, the amplitude of the portion on the outer side of the transmission becomes larger on the transmission shaft on the upper side, and the portion on the right and left center side of the aircraft. It is considered that the smaller the amplitude, the smaller the amplitude.

According to the feature of claim 1, the moving operation part of the upper transmission shaft is arranged on the left and right center side of the machine which is the side with the smaller amplitude in the upper transmission shaft, similarly to the movable pulley piece of the upper pulley. Therefore, it is possible to suppress occurrence of backlash in the moving operation portion of the transmission shaft on the better side.

Further, according to the feature of claim 1, as described in (iv) and (v) above, the moving operation part of the upper transmission shaft and the moving operation part of the lower transmission shaft are connected by the linking member. ,
Since the linking member is in a state in which the two moving operation parts suppress each other's vibration, even if the vibration of the engine is transmitted to the good transmission shaft, there is a play in the moving operation part of the good transmission shaft. Can be further suppressed.

(Vii) According to the features of claim 2, similar to the case of claim 1, the “action” described in the preceding items (i) to (vi) is provided, and in addition to this, the following “ Action ".

According to the feature of claim 2, the engine and the transmission case are arranged in front and rear at the front of the body so that the engine is located on the front side of the transmission case, so that the engine and the transmission case are arranged like a riding rice transplanter. In a work vehicle equipped with a seedling planting device at the rear, the engine and the transmission case function as balance weights at the front of the body, and the weight balance of the entire body is improved.

In this case, if the engine is mounted on the transmission case at the front of the fuselage, the hood covering the engine becomes high, so that the driver may have a narrow front view obliquely downward. Claim 2.
According to the features of the above, since the engine and the transmission case are arranged side by side at the front of the fuselage, the hood covering the engine does not become high, and the forward visibility obliquely downward for the driver does not become narrow. .

[Effect of the Invention] According to the feature of claim 1, in the transmission structure of a working vehicle equipped with a belt-type continuously variable transmission, the movable pulley piece of the upper pulley is moved on the side of the lower transmission shaft with the smaller amplitude on the upper transmission shaft. By arranging them on the left and right center sides of a certain fuselage, it was possible to suppress the occurrence of rattling at the fitting portion between the transmission shaft on the better side and the movable pulley piece. As a result, the movable pulley piece of the upper pulley can be smoothly slid, irrespective of long-term use, and the speed change operation of the work vehicle can be stabilized.

According to the feature of claim 1, the lower the rotation speed and the higher the torque, the higher the speed of the transmission belt (the greater the tension of the transmission belt), the more the transmission belt moves to the left and right center side of the fuselage. The repetitive compressive and tensile stresses generated in the transmission shaft of Example 1 can be reduced as a whole. Thereby, the progress of brittle fracture due to repeated stress could be suppressed, and the durability of the belt-type continuously variable transmission could be improved.

According to the feature of claim 1, a point that the moving operation part of the upper transmission shaft and the moving operation part of the lower transmission shaft are connected by the linking member, and both the high-speed side and the low-speed side shifting operation , The sliding operation of one of the movable pulley pieces of the upper and lower pulleys assists the sliding operation of the other movable pulley piece of the upper and lower pulleys. The shift performance of the belt-type continuously variable transmission can be improved because the one and the movable pulley pieces of the lower pulley are slid to the low speed side and the high speed side without delay.

According to the feature of claim 1, when performing the speed change operation of the belt type continuously variable transmission, the sliding operation of one movable pulley piece of the upper side pulley and the lower side pulley is performed in both the high speed side and the low speed side. , Which assists the sliding operation of the other movable pulley piece of the upper side puller and the lower side pulley, and the operating force is the same in both the high speed side and the low speed side shifting operation, so that a large operating force is repeatedly applied. It was possible to prevent a decrease in durability due to this.

According to the feature of claim 1, similarly to the movable pulley piece of the upper side pulley, the moving operation portion of the upper side transmission shaft is arranged on the left and right center side of the machine body which is the side of the lower side transmission shaft where the amplitude is small. Thereby, it is possible to suppress the occurrence of backlash in the moving operation portion of the transmission shaft on the upper side, and it is possible to smoothly slide the movable pulley piece of the upper side pulley regardless of use for a long time, The shifting operation of the work vehicle was further stabilized.

According to the feature of claim 1, by connecting the moving operation part of the upper transmission shaft and the moving operation part of the lower transmission shaft by the linking member, both the moving operation parts vibrate each other by the linking member. Can be obtained, and the occurrence of backlash in the moving operation portion of the transmission shaft on the better side can be further suppressed, and the speed change operation of the work vehicle can be further stabilized.

According to the features of claim 2, similar to the case of claim 1, the above-mentioned "effect of the invention" of the claim 1 is provided, and in addition to the "effect of the invention", the following " Effect of the Invention ".

According to the feature of claim 2, by arranging the engine and the transmission case at the front of the fuselage so that the engine is located at the front side of the transmission case, the engine and the transmission case are arranged side by side so that the weight balance of the entire aircraft is improved, and As a result, it is possible to secure a forward view obliquely downward for the worker, and to improve the running stability and the maneuverability of the work vehicle.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIG. 3, the engine (1) and the transmission case (2) are arranged side by side at the front of the body so that the engine (1) is located in front of the transmission case (2). The power from the engine (1) is transmitted to the transmission case (2) through the belt-type continuously variable transmission (A), and the front wheel (3) and the rear wheel (4) are driven by the power from the transmission case (2). A traveling body (B) is formed by forming a transmission system so as to be driven. A boarding operation section (C) is formed at the center of the traveling body (B), and a working mechanism of the working device is connected to a rear end of the traveling body (B) via a link mechanism (6) that is lifted and lowered by a hydraulic silling (5). A riding type rice transplanter (corresponding to a work vehicle) is configured by connecting a seedling planting device (D) as an example.

As shown in FIG. 3, the onboard driving section (C) includes a steering handle (7) for operating the front wheel (3), a main shift lever (8) and a seat (9) linked to the transmission case (2). At the side of the seat (9), there is provided an artificial speed change lever (10) for shifting the speed of the belt type continuously variable transmission (A) independently of a later-described linkage mechanism (E) (see FIG. 1). Have been.

As shown in FIGS. 1 and 2, the belt-type continuously variable transmission (A) has a split pulley type output provided on an output shaft (1a) of the engine (1) (corresponding to the upper transmission shaft). Split pulley type input pulley (12) (corresponding to the lower pulley) provided on the pulley (11) (corresponding to the upper pulley) and the input shaft (2a) (corresponding to the lower transmission shaft) of the transmission case (2) Equivalent),
It comprises a transmission belt (13) wound around output and input pulleys (11) and (12), and a tension pulley (14) for tensioning the transmission belt (13). Transmission belt (13) linked with (11) and (12)
And an interlocking rod (15) (corresponding to a linking member) for changing the winding radius of the motor. The tension pulley (14) is provided on an arm (29) swingably supported around a fulcrum (Z).

The output and input pulleys (11) and (12) are configured such that the movable pulley pieces (11a) and (12a) are slidable in the axial direction by a climbing type cam mechanism (F).
The roller (23) of the fixed cam (23) in the cam mechanism (F)
The rotating cam (24) is interlocked and connected by the interlocking rod (15) so that the rotating cam (24) (corresponding to the moving operation unit) having a rolling inclined surface that slides on a) is rotated in the same direction. Have been.

In this case, as shown in FIG. 2, in the output pulley (11), the movable pulley piece (11a) slid along the output shaft (1a) and the cam mechanism (F) are connected to the body of the output shaft (1a). A fixed pulley piece (11b) arranged on the left and right center side and fixed to the output shaft (1a) is arranged outside the body of the output shaft (1a). At the input pulley (12),
A movable pulley piece (12a) and a cam mechanism (F) slid along the a) are disposed outside the body of the input shaft (2a), and are fixed to the input shaft (2a).
Are arranged on the left and right sides of the input shaft (2a).

Therefore, the input pulley (1) is set so that the winding radius of the transmission belt (13) at the input pulley (12) is reduced (high-speed side).
When the movable pulley piece (12a) of 2) is slid to the outside of the body, the movable pulley piece (11a) of the output pulley (11) is slid to the fixed pulley piece (11b) side (outside of the body) to output. The winding radius of the transmission belt (13) at the pulley (11) increases. On the other hand, the movable pulley piece (12a) of the input pulley (12) is fixed to the fixed pulley piece (1) so that the winding radius of the transmission belt (13) on the input pulley (12) becomes large (low speed side).
2b) When the sliding operation is performed to the side (the left and right center side of the machine), the movable pulley piece (11a) of the output pulley (11) is slid to the left and right center side of the machine, and the transmission belt (13) of the output pulley (11) is moved. ) Becomes smaller.

As shown in FIG. 1, the swing bracket (1) supported swingably around the left and right axis (P) of the body frame (17).
8), the base end of the artificial speed change lever (10) is connected and fixed, and extends to the side of the seat (9) via the guide member (19). It is configured to be able to swing around the axis (P) and to be fixed at a desired operation position by a guide member (19).

Below the swinging bracket (18), a contact bracket (20) is swingably supported around the left and right axis (Q) of the body frame (17), and is formed as a flexible to the contact bracket (20). A connecting rod (21) is provided over the elongated hole (20h) and one end of the swing bracket (18), and an upper operating point formed on the rotary cam (24) on the input pulley (12) side. (16) and the contact bracket (20) are connected via an operation rod (22). Thus, when the artificial transmission lever (10) is operated to the high speed side (H) shown in FIG. 1, the traveling speed of the aircraft increases, and when the artificial lever is operated to the low speed side (L), the traveling speed of the aircraft decreases.

As shown in FIG. 1, when the arm portion (20a) is formed on the contact bracket (20) and the seedling planting device (D) is raised, the contact mechanism provided on the link mechanism (6) is raised. Piece (6a)
The contact bracket (20) is configured to be rocked by the contact pressing, and thus the linkage mechanism (E) is configured to automatically reduce the traveling speed.

Move the upper operating point (16) of the rotating cam (24) on the input pulley (12) side and the contact bracket (20) to the operating rod (22).
A link mechanism (E) is constituted by interlocking connection, and the upper operation point (16) is urged toward the output shaft (1a) by a spring (25) to thereby provide a belt-type continuously variable transmission (A). ) To the high-speed side (H).

The horizontal pin (16a) of the upper operation point (16) is inserted into the long hole (26) formed in the front and rear of the operation rod (22), and the belt type is independent of the operation of the link mechanism (E). The shift operation to the low-speed side (L) of the step transmission (A) becomes possible (the rearward movement of the horizontal pin (16a) becomes possible). The operation rod (22) is constantly urged forward by a spring (27), and the arm (20a) of the contact bracket (20) and the contact piece (6a) of the link mechanism (6) are connected. It is always in contact.

Operating point (31) of rotating cam (24) on output pulley (11)
And the interlocking rod (15), the pin (31a) of the operating point (31) is inserted into the long hole (15b) formed in the long plate portion (15a) of the operating rod (15), and the pin (31a) is Two springs (3
The pin (31a) is pulled back and forth in 2), and the pin (31a)
It is configured to stop at the middle position before and after b).

As described above, when the seedling planting device (D) is raised and the running speed is automatically reduced by the linkage mechanism (E),
When the seedling planting device (D) is lowered to the working level, the running speed is restored to the running speed by the artificial transmission lever (10). When the artificial speed change lever (10) is operated to the low speed side (L) in the state where the automatic deceleration operation is performed as described above, the contact bracket (20) is opposed to the spring (27) by the link mechanism (6). The traveling speed can be further reduced by swinging in a direction away from the contact piece (6a). The long hole (20h) formed in the contact bracket (20) is formed to a size that allows the above-mentioned automatic deceleration operation, and when the deceleration operation is further performed by the artificial transmission lever (10) as described above. First, the artificial speed change lever (10) is operated to the low speed side (L) by the stroke allowed by the long hole (20h), and then the speed reduction operation is performed.

If the disturbance load increases in a state where the automatic deceleration operation is performed without operating the artificial transmission lever (10), the belt-type continuously variable transmission (A) automatically opposes the spring (25). The lateral pin (16a) of the upper operation point (16) moves rearward so as to increase the transmission torque, but without affecting the linkage mechanism (E) by the elongated hole (26). The movement of the upper operation point (16) is performed. Next, when the driving load is reduced, the belt-type continuously variable transmission (A) returns to the original automatic deceleration state by the self-shifting action of the belt-type continuously variable transmission (A). In this case, it is convenient to set the long hole (26) to a length that covers the entire speed change operation range.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the structure shown in the attached drawings.

[Brief description of the drawings]

The drawings show an embodiment of the transmission structure of the working vehicle according to the present invention,
1 is a side view showing a belt type continuously variable transmission, FIG. 2 is a plan view showing a belt type continuously variable transmission, and FIG. 3 is a side view of a riding type rice transplanter. (1) ... engine, (1a) ... good transmission shaft,
(2) ... transmission case, (2a) ... lower transmission shaft,
(11)… better pulley, (11a)… movable pulley piece of better pulley, (11b)… fixed pulley piece of better pulley, (12)… lower pulley, (12a)… lower Movable pulley piece of side pulley, (12b) ... fixed pulley piece of lower pulley, (13) ... transmission belt, (15) ... linking member,
(24): Moving operation unit, (A): Belt-type continuously variable transmission.

Claims (2)

(57) [Claims] An upper transmission shaft (1a) and a lower transmission shaft (2a) in a transmission system are protruded in a cantilever manner toward the same side in the lateral direction of the machine body. Each of the side transmission shafts (1a) and (2a) is provided with an upper pulley (11) and a lower pulley (12) of a split pulley type, and the upper and lower pulleys (11),
A transmission belt (13) is wound around (12) to form a belt-type continuously variable transmission (A). In the upper pulley (11), along the upper transmission shaft (1a). Sliding movable pulley piece (11
a) and a moving operation unit (24) that slides the movable pulley piece (11a) along the upper transmission shaft (1a),
The fixed pulley piece (11b) which is arranged on the left and right center of the body of the upper transmission shaft (1a) and is fixed to the upper transmission shaft (1a) is connected to the upper transmission shaft (1a). A movable pulley piece (12) that is disposed outside the body and is slidable along the lower transmission shaft (2a) at the lower pulley (12).
a) and a moving operation unit (24) that slides the movable pulley piece (12a) along the lower transmission shaft (2a),
A fixed pulley piece (12) that is arranged outside the lower transmission shaft (2a) and fixed to the lower transmission shaft (2a).
b) is disposed at the center of the lower transmission shaft (2a) on the left and right sides of the machine body, and the movement operation part (24) of the upper transmission shaft (1a) and the movement of the lower transmission shaft (2a) A linking member (15) is connected to the operating portion (24), and the upper and lower transmission shafts (1) are connected by the linking member (15) and the moving operating portion (24).
a) A transmission structure of a working vehicle in which the movable pulley pieces (11a) and (12a) of (2a) are configured to be slid to a lower speed side and a higher speed side. 2. An engine (1) and a transmission case (2) are arranged in front and rear of the body so that the engine (1) is located in front of the transmission case (2). The front transmission shaft (1a), which is the engine (1) side, and the lower transmission shaft (2a), which is the transmission case (2) side, on the same side in the lateral direction of the fuselage. The upper and lower transmission shafts (1a) and (2a) are provided with a split pulley type upper pulley (11) and a lower pulley (12), respectively. The upper and lower pulleys (11),
A transmission belt (13) is wound around (12) to constitute a belt-type continuously variable transmission (A). In the upper pulley (11), the transmission belt (13) extends along the upper transmission shaft (1a). Sliding movable pulley piece (11
a) and a moving operation unit (24) that slides the movable pulley piece (11a) along the upper transmission shaft (1a),
The fixed pulley piece (11b) which is arranged at the center of the body of the upper transmission shaft (1a) on the left and right sides of the machine body and is fixed to the upper transmission shaft (1a) is attached to the upper transmission shaft (1a). A movable pulley piece (12) that is disposed outside the body and is slidable along the lower transmission shaft (2a) at the lower pulley (12).
a) and a moving operation unit (24) that slides the movable pulley piece (12a) along the lower transmission shaft (2a),
A fixed pulley piece (12) that is arranged outside the lower transmission shaft (2a) and fixed to the lower transmission shaft (2a).
b) is disposed at the center of the lower transmission shaft (2a) on the left and right side of the machine body, and the movement operation part (24) of the upper transmission shaft (1a) and the movement of the lower transmission shaft (2a) A linking member (15) is connected to the operating portion (24), and the upper and lower transmission shafts (1) are connected by the linking member (15) and the moving operating portion (24).
a) A transmission structure of a working vehicle in which the movable pulley pieces (11a) and (12a) of (2a) are configured to be slid to a lower speed side and a higher speed side.