JP2005003091A - Power transmission in running work machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compact a power transmission 7 having a hydraulic/mechanical transmission mechanism in a running work machine. <P>SOLUTION: The power transmission in the running work machine transmits a power from an engine to a stationary oil hydraulic transmission having a planetary gear mechanism 30, a variable type hydraulic pump 31, and a variable hydraulic motor 32; and synthesizes the outputs of the stationary oil hydraulic transmission and the planetary gear mechanism to a variable speed output. A carrier 36 having planetary gears 37 on the outer periphery of a sun gear shaft 34 rotatable in the planetary gear mechanism 30 is rotatably engaged with an inner peripheral ring gear 39 engaged with the planetary gear 37, to transmit the power from the engine to transmission gears 35 provided on the outer periphery of the carrier 36 to drive the variable type hydraulic pump 31 through the outer ring gear 40 of the ring gear 39. Meanwhile, the power from the variable hydraulic motor 32 operating by its hydraulic oil is input to the sun gear shaft 34 through a transmission gear 45 to transmit the power from the sun gear shaft 34 to a runner. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a power transmission device in a traveling work machine such as an agricultural work machine or a civil engineering work machine that includes a hydrostatic transmission mechanism (device) and a mechanical transmission mechanism.
[0002]
[Prior art]
Conventionally, power from an engine is divided and input into a mechanical transmission mechanism including a planetary gear mechanism and a hydrostatic transmission mechanism including a hydraulic pump and a hydraulic motor, and the hydrostatic transmission mechanism and the planetary gear mechanism are input. A power transmission device that combines the outputs of the above to produce a shift output is known, for example, in Patent Document 1 and the like.
[0003]
In the configuration of Patent Document 1, an input shaft from a prime mover such as an engine is sequentially and coaxially connected to an output shaft via a high speed ratio range clutch, an intermediate shaft, and a gear unit including a planetary gear mechanism. The input shaft further includes a pair of gears engaged with each other, a rotary shaft, a pair of other gears engaged with each other, a clutch for a low speed ratio region, and other intermediate shafts in the same manner. Connected to the unit.
[0004]
On the other hand, in the hydraulic unit, when one of the two hydraulic pumps / motors acts as a pump by the hydraulic circuit, the other hydraulic pump / motor is connected to act as a motor with the other hydraulic power. It is connected to the rotating shaft. The rotary shaft from the other hydraulic pump / motor is connected to the gear unit via another set of gears that engage with each other and a reaction force shaft, and travels backward with another set of gears that engage with each other. It is connected to the output shaft via a clutch.
[0005]
The gear unit has the same configuration as that of the front single planetary gear including the first sun gear, the first pinion, the first ring gear, and the first carrier that pivotally supports the first pinion, that is, the second sun gear, the second pinion, the second A single planetary gear in the rear row comprising a ring gear and a second carrier that pivotally supports the second pinion is provided. The first sun gear is coupled to the reaction force shaft, the first ring gear and the second sun gear are coupled to the first intermediate shaft, the second ring gear is coupled to the second intermediate shaft, and the first and first Two carriers are coupled to the output shaft, and a low speed gear ratio or a high speed gear ratio is obtained by only the single planetary gear in the front row or both single planetary gears, respectively.
[0006]
The one hydraulic pump / motor is a variable displacement type, and the other hydraulic pump / motor is a fixed displacement type.
[0007]
[Patent Document 1]
Japanese Patent Publication No. 56-23069
[Problems to be solved by the invention]
However, according to the configuration of Patent Document 1, the second intermediate shaft coupled with the second sun gear and the first ring gear can be rotated relative to the first intermediate shaft coupled with the second ring gear. It is fitted. A reaction force shaft coupled with the first sun gear is fitted so as to be rotatable relative to the second intermediate shaft. Accordingly, in the portion where the three shafts of the first intermediate shaft, the second intermediate shaft, and the reaction force shaft are partially concentrically overlapped, the maximum diameter of the shaft must be increased. As the structure of the bearing becomes complicated, the diameter of the gear coupled to these shafts has to be increased, resulting in a problem that the configuration of the gear is increased.
[0009]
Further, in the above-described configuration, there is a problem in that the entire transmission case becomes long and cannot be made compact as a result of the linear arrangement from the input shaft from the prime mover to the output shaft of the transmission case.
[0010]
Further, two hydraulic pumps / motors that are branched and driven from the planetary gear from the input shaft from the prime mover are arranged in series, and the output of the other hydraulic pump / motor is input to the sun gear in the single planetary gear in the front row. Because of this configuration, two hydraulic pumps / motors have to be arranged in the mission case, and the maintenance of the hydraulic pump / motor requires a troublesome task of disassembling the mission case.
[0011]
The present invention divides and inputs a mechanical transmission mechanism comprising a planetary gear mechanism and a hydrostatic transmission mechanism comprising a hydraulic pump and a hydraulic motor, and outputs each of the hydrostatic transmission mechanism and the planetary gear mechanism. It is an object of the present invention to make the configuration of a power transmission device that is combined to produce a shift output compact.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a power transmission device in a traveling working machine according to claim 1 is a hydrostatic transmission comprising a planetary gear mechanism, a variable hydraulic pump, and a variable hydraulic motor for transmitting power from the engine. In a traveling working machine that transmits power to the device and combines the outputs of the hydrostatic transmission and the planetary gear mechanism to produce a transmission output, a planetary gear is disposed on the outer periphery of the rotatable sun gear shaft in the planetary gear mechanism. A variable hydraulic pump through which a carrier provided and a ring gear meshing with the planetary gear are rotatably fitted, the power from the engine is transmitted to a gear provided on the outer periphery of the carrier, and the ring gear is used for transmission. The power from the variable hydraulic motor is input to the sun gear shaft through a transmission gear, and the power is transmitted from the sun gear shaft to the traveling unit. It is intended.
[0013]
According to a second aspect of the present invention, in the power transmission device for the traveling work machine according to the first aspect, an auxiliary transmission mechanism is disposed between the sun gear shaft and the traveling unit.
[0014]
According to a third aspect of the present invention, in the power transmission device in the traveling work machine according to the first or second aspect, the diameter of the transmission gear on the variable hydraulic motor side is smaller than the transmission gear on the variable hydraulic pump side. It is set.
[0015]
According to a fourth aspect of the present invention, in the power transmission device for a traveling work machine according to any one of the first to third aspects, the transmission case incorporating the planetary gear mechanism is connected to a rear axle case, A PTO shaft is provided at the rear end so as to transmit power to the PTO shaft via a power shaft from the engine and a transmission shaft in the transmission case.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, a preferred embodiment in which the present invention is embodied will be described. FIG. 1 is a side view of a wheel loader used for agricultural work or civil engineering work as an example of a traveling work machine, FIG. 2 is a plan view of a traveling machine body, FIG. 3 is a skeleton diagram of a power transmission device, and FIG. FIG. 5 is a partially cutaway side view showing the planetary gear mechanism and the like, and FIG. 5 is a front view taken along line VV in FIG.
[0017]
As shown in FIG. 1, the wheel loader 1 used for agricultural work or civil engineering work includes a pair of front wheels 3 and 3 and a pair of rear wheels 4 and 4 on both the left and right sides of the traveling machine body 2. As will be described later, the engine 5 mounted on the front part of the traveling machine body 2 transmits power to a power (transmission) transmission device 7 provided at the rear part of the traveling machine body 2 via an output shaft 6, and the output is differentially limited. The transmission is transmitted to the rear wheels 4 and 4 through the rear wheel final reduction device 8 with a front wheel, and is transmitted from the front wheel drive shaft 9 to the front wheels 3 and 3 through the front wheel final reduction device 10 with a differential limiting device. Has been.
[0018]
A steering column 12 having a round handle 11 at the rear of the engine 5 is erected on the upper surface of the traveling machine body 2, and a vehicle body cover covering the upper part of the transmission case 13 of the power transmission device 7 is further rearward. A driver seat 15 is provided on the upper surface of 14.
[0019]
A pair of left and right pillars 17 are erected at the front portion of the traveling machine body 2, and a bucket 16 is pivotally attached to the tips of a pair of left and right booms 18 pivotally attached to the upper ends of the pillars 17. The boom 18 is moved up and down by the operation of the lifting hydraulic cylinder 19 mounted between the traveling machine body 2 and the middle part of the boom 18. The lower end of the dump arm 20 pivotally attached to the middle portion of the boom 18 is pivotally attached to the bucket 16, and the operation of the dump hydraulic cylinder 21 mounted between the upper end of the dump arm 20 and the pillar 17 is performed. Thus, the vertical direction of the bucket 16 can be changed.
[0020]
Next, a configuration for transmitting the power from the engine 5 to the traveling system and the working system will be described. As shown in FIGS. 2 and 3, the output shaft 22 projects into the case 23 provided on the rear surface of the engine 5. The gear 24 attached to the output shaft 22 meshes with an idler gear 25, and the idler gear 25 is attached to a power shaft and meshes with a gear 27. The power shaft extends in the rear direction of the traveling machine body 2 and faces the mission case 13 in the rear power transmission device 7. The power (transmission) transmission device 7 includes a hydraulic / mechanical transmission mechanism (HMT) including a hydrostatic transmission mechanism (HST) including a hydraulic pump 31 and a hydraulic motor 32 and a mechanical transmission mechanism including a planetary gear mechanism. It is configured.
[0021]
A hydraulic pump 29 attached to the rear surface of the case 23 with a bolt or the like is concentrically connected to the output shaft 22, and pressure oil generated by the hydraulic pump 29 by driving the engine 5 is supplied to the lifting hydraulic cylinder. 19 and the dump hydraulic cylinder 21 can be supplied. The number of teeth of the gear 24, idler gear 25, and gear 27 is set so that power is transmitted from the output shaft 22 to the power shaft at the same rotational speed.
[0022]
Next, the configuration of power transmission to the planetary gear mechanism 30 in the transmission case 13 and the hydraulic pump 31 and the hydraulic motor 32 for shifting that are detachably mounted on the front surface of the transmission case 13 will be described with reference to FIGS. As shown in FIG. 5, the gear 33 to which the power shaft is connected meshes with a transmission gear 35 that is rotatable with respect to the sun gear shaft 34. A carrier 36 is fixed to one surface of the transmission gear 35, and a plurality (three in the embodiment, see FIG. 5) of planetary gears 37 are rotatably supported on the carrier 36. A sun gear 38 fixed or formed so as to rotate integrally with the outer periphery of the sun gear shaft 34 meshes with all the planetary gears 37. The sun gear shaft 34 meshes with a rotatable inner ring gear 39 and all the planetary gears 37. A gear 41 that meshes with the outer ring gear portion 40 formed on the opposite side surface of the inner ring gear 39 is fixed to an input shaft 42 to the hydraulic pump 31. In the embodiment, as shown in FIGS. 3 and 4, the transmission gear 35 and the sun gear 38 are arranged along the axial direction of the sun gear shaft 34, and the outer peripheral ring gear portion 40 is disposed on the opposite side of the transmission gear 35 across the sun gear 38. Is arranged, and the inner ring gear 39 and the planetary gear 37 are located on the outer circumference from the sun gear 38.
[0023]
On the other hand, a gear 44 is fixed to the output shaft 43 connected to the hydraulic motor 32 disposed on the front surface of the transmission case 13, and the gear 44 and the transmission gear 45 fixed to the sun gear shaft 34 are engaged with each other.
[0024]
Large and small gears 46 and 47 are fixed to the sun gear shaft 34, and a mechanical sub-transmission mechanism 49 is provided on the counter shaft 48 disposed in parallel with the sun gear shaft 34 in the transmission case 13. . That is, a shifter 49a (see FIG. 4) of the subtransmission mechanism 49 is slidably fitted to the spline portion of the counter shaft 48, and the shifter 49a is selectively connected to one of the large and small gears 46, 47 for shifting. Gears 50 and 51 that mesh with each other are fixed. Further, power is transmitted from the counter shaft 48 to the rear wheel final reduction device 8 with a differential limiting device for the rear wheels, and a gear 52 fixed to the counter shaft 48 is connected via a gear 53 with a clutch 54. Then, power is transmitted from the front wheel drive shaft 9 to the front wheel final reduction gear 10. The power from the engine 5 is transmitted from a gear 56 fixed to the power shaft to a PTO shaft 58 via a gear 57 and transmitted to a working machine (not shown) connected to the rear portion of the traveling machine body 2. It is possible (see FIG. 3).
[0025]
4, both ends of the sun gear shaft 34 are supported by bearings 60 and 61, and ring gears 39 and 40 are fitted on the outer periphery of the sun gear shaft 34 via a bearing 62 so as to be relatively rotatable. A sun gear 38 fixed or formed to rotate integrally with the outer periphery of the shaft 34 and a planetary gear 37 meshing with the ring gear 39 are relatively rotatable via a bearing 63 on the outer periphery of the sun gear shaft 34. Since the gear 33 is attached to the carrier 36 and the gear 33 for inputting power is engaged with the transmission gear 35 formed on a part of the carrier 36, the ring gears 39, 40 and the carrier 36 and the sun gear shaft 34 The relationship does not become a triple axis, and the diameters of the ring gears 39 and 40 and the carrier 36 do not have to be increased.
[0026]
Further, a gear 41 for power transmission to the hydraulic pump 31 is disposed in an outer ring gear portion 40 formed in a part of the inner ring gear 39, and a gear 44 for transmitting power from the hydraulic motor 32 is disposed on the sun gear shaft. 34 is meshed with a transmission gear 45 fitted so as to rotate integrally therewith, and a power shaft gear 33 which is an input shaft for power from the engine 5 is connected to a transmission gear 35 on the outer periphery of the sun gear shaft 34. Since the gears are engaged, the power shaft 26 can be arranged so as to protrude from the transmission case 13 at a position eccentric from the axis of the sun gear shaft 34. Therefore, when the HST case 64 of the hydraulic pump 31 and / or the hydraulic motor 32 is mounted on the front surface of the transmission case 13, as viewed from the front of the transmission case 13 (in front of the traveling machine body 2), as shown in FIG. Further, the HST case 64 can be arranged so as to overlap within the projection range of the power shaft. Thereby, the power transmission device 7 as a hydraulic / mechanical transmission mechanism (HMT) can be compactly formed.
[0027]
Further, when the hydraulic / mechanical transmission mechanism of the power transmission device 7 is observed in the axial direction of the sun gear shaft 34, the power shaft 26 and the HST (hydraulic pump 31 and Since the input and output portions for the hydraulic motor 32) and the countershaft 48 of the auxiliary transmission mechanism can be arranged, the components (shafts, gears, etc.) are arranged compactly in the transmission case 13 without interfering with each other. There is an effect that can be made.
[0028]
The power from the engine 5 is transmitted from the outer ring gear 40 of the ring gear 39 to the sun gear shaft 34 through the power shaft → the gear 33 → the transmission gear 35 → the ring gear 39 → the planetary gear 37 → the sun gear 38. The power is divided such that the hydraulic pump 31 is driven via the gear 40. The output of the hydraulic motor 32 is transmitted to the sun gear shaft 34 through gears 44 and 45, so that the power of the fluid transmission system is combined with the mechanical transmission system.
[0029]
FIG. 6 shows the state of the vehicle speed when the traveling machine body moves forward and backward due to the operation of the hydraulic pump 31 and the hydraulic motor 32. When the engine 5 is started, the swash plate angle of the hydraulic pump 31 is 0 (neutral), and the swash plate angle of the hydraulic motor 32 is set to the maximum value. In this state, since the hydraulic motor 32 is braked by the hydraulic pump 31, the gears 44 and 45 are stopped and the sun gear shaft 34 does not rotate. The ring gear 39 and the carrier 37 are rotated from the power shaft through the gear 33 and the transmission gear 35, but only rotate while revolving in a state where the planetary gear 37 meshes with the fixed sun gear 38. In this state, the traveling machine body 2 is kept stopped.
[0030]
In order to increase the vehicle speed at the time of forward movement, when the swash plate angle of the hydraulic pump 31 is gradually increased in the positive direction while the swash plate angle of the hydraulic motor 32 is fixed at the maximum value, the hydraulic pump 31 moves to the hydraulic motor 32. The pressure oil discharge amount gradually increases, and the number of forward rotations of the hydraulic motor 32 increases. In this case, the hydraulic motor 32 increases the rotational speed while maintaining a constant high torque. Since the sun gear shaft 34 is rotated forward by the rotation of the hydraulic motor 32, this output is transmitted to the rear wheel final reduction device 8 and the front wheel final reduction device 10 through the auxiliary transmission mechanism 49, and the front wheel 3 and the rear wheel 4 are moved. Drive in the forward direction. On the other hand, since the ring gear 39 is relatively rotated by the positive rotation of the sun gear shaft 34, the rotational speed of the hydraulic pump 31 is gradually decreased.
[0031]
After the swash plate angle of the hydraulic pump 31 reaches the maximum value, the maximum value is maintained, while the swash plate angle of the hydraulic motor 32 is gradually decreased from the maximum value (returned to the neutral direction). As a result, the volume of the hydraulic motor 32 gradually decreases, and the rotational speed of the hydraulic motor 32 increases while decreasing the torque. In this case, since the rotational speed of the sun gear shaft 34 increases, the rotational speed of the ring gear 39 relatively decreases, and the rotational speed of the hydraulic pump 31 decreases.
[0032]
In this way, the variable hydraulic motor 32 increases the speed of the sun gear shaft 34 and decreases the rotation speed of the ring gear 39, so that the flow rate of the pressure oil decreases as the rotation speed of the variable hydraulic motor 32 increases. Because it is mechanical power transmission, energy efficiency is improved.
[0033]
In the embodiment, when the shaft rotational speed of the hydraulic pump 31 is 0, the shaft rotational speed of the hydraulic motor 32 becomes the maximum value (4778 rpm).
[0034]
On the other hand, when the traveling machine body 2 is moved backward from the stopped state, the swash plate angle of the hydraulic pump 31 is gradually increased from neutral to the negative direction while the swash plate angle of the hydraulic motor 32 is maintained at the maximum value. As a result, the amount of pressure oil discharged from the hydraulic pump 31 to the hydraulic motor 32 gradually increases, and the reverse rotation speed of the hydraulic motor 32 increases. Thus, the traveling machine body 2 starts to move backward. On the other hand, since the rotation from the power shaft is added to the ring gear 39 due to the reverse rotation of the sun gear shaft 34, the rotational speed of the hydraulic pump 31 gradually increases.
[0035]
After the swash plate angle of the hydraulic pump 31 reaches the maximum value in the negative direction, the maximum value is maintained, while the swash plate angle of the hydraulic motor 32 is gradually decreased from the maximum value so that the hydraulic motor 32 While decreasing the torque, the reverse rotation speed increases. In the embodiment, when the shaft rotation speed of the hydraulic pump 31 is the maximum value (3856 rpm) in the forward rotation direction, the shaft rotation speed of the hydraulic motor 32 is the maximum value (3856 rpm) in the reverse rotation direction (see FIG. 6).
[0036]
As described above, the rotational speed of the hydraulic motor 32 becomes very high and the rotational speed of the hydraulic pump 31 approaches 0 at the maximum speed due to the configuration of the input division type HST, so that the gear noise can be reduced. It is desirable to make the gear 44 of the shaft 43 of the hydraulic motor 32 smaller than the gear 41 of the shaft 42 of the hydraulic pump 31.
[0037]
Immediately after starting the engine, the planetary gear mechanism 30 may be provided with a brake means for applying a brake to the sun gear shaft 34 in the instantaneous movement due to the hydraulic pressure leak from the hydraulic motor 32 and the hydraulic pump 31. For this purpose, a multi-plate type brake mechanism 65 associated with the counter shaft 48 or the like of the auxiliary transmission mechanism 49 shown in FIG. 6 may be provided.
[0038]
In order to transmit the power from the engine 5 to the PTO shaft 58 without passing through the planetary gear mechanism 30 or the HST, the power shaft 26 passes through the gears 56 and 57 to be coaxial with the sun gear shaft 34 or travel. The PTO shaft 58 can be arranged on the left and right central axis of the machine body 2.
[0039]
【The invention's effect】
As described in detail above, the power transmission device in the traveling working machine according to the first aspect of the present invention is a hydrostatic transmission that includes a planetary gear mechanism, a variable hydraulic pump, and a variable hydraulic motor for transmitting power from the engine. In a traveling working machine that transmits power to the device and combines the outputs of the hydrostatic transmission and the planetary gear mechanism to produce a transmission output, a planetary gear is disposed on the outer periphery of the rotatable sun gear shaft in the planetary gear mechanism. A variable hydraulic pump through which a carrier provided and a ring gear meshing with the planetary gear are rotatably fitted, the power from the engine is transmitted to a gear provided on the outer periphery of the carrier, and the ring gear is used for transmission. The power from the variable hydraulic motor is input to the sun gear shaft through a transmission gear, and the power is transmitted from the sun gear shaft to the traveling portion. It is.
[0040]
Accordingly, since the ring gear and the carrier arranged in the axial direction on the outer periphery of the sun gear shaft are free to rotate with respect to the sun gear shaft, the ring gear and the carrier do not become a triple shaft at the fitting position of the sun gear shaft. The structure of the power transmission (transmission) device can be made compact.
[0041]
Further, a gear for transmitting power to the hydraulic pump is disposed in an outer ring gear portion formed in a part of the inner ring gear, and a gear for transmitting power from the hydraulic motor rotates integrally with the sun gear shaft. Further, since the gear of the power shaft that is meshed with the fitted transmission gear is meshed with the transmission gear on the outer periphery of the sun gear shaft, the shaft center of the sun gear shaft is engaged. The power shaft can be arranged so as to protrude from the transmission case at a position eccentric from the transmission case. Accordingly, the case of the hydrostatic transmission mechanism mounted on the front surface of the transmission case can be disposed so as to overlap within the projection range of the power shaft. Thereby, the power transmission device as the hydraulic / mechanical transmission mechanism (HMT) can be formed compactly.
[0042]
In addition, the variable hydraulic motor increases the speed of the sun gear shaft and decreases the rotation speed of the ring gear, so that the flow rate of pressure oil decreases as the rotation speed of the variable hydraulic motor increases, and mechanical power transmission As a result, the energy efficiency is improved.
[0043]
According to a second aspect of the present invention, in the power transmission device for the traveling work machine according to the first aspect, an auxiliary transmission mechanism is disposed between the sun gear shaft and the traveling unit. In this case, in addition to the effect of the invention according to claim 1, the power shaft, the input portion and the output portion for the HST, and the shaft of the auxiliary transmission mechanism can be arranged around 360 degrees on the outer periphery from the sun gear shaft. These components (shafts, gears, etc.) are arranged compactly in the transmission case without interfering with each other, and the power transmission device can be made more compact.
[0044]
According to a third aspect of the present invention, in the power transmission device in the traveling work machine according to the first or second aspect, the diameter of the transmission gear on the variable hydraulic motor side is smaller than the transmission gear on the variable hydraulic pump side. It is set.
[0045]
Therefore, in addition to the effect of the invention according to the first or second aspect, the rotational speed of the hydraulic motor becomes very high and the rotational speed of the hydraulic pump approaches 0 at the maximum speed due to the configuration of the input division type HST. Therefore, there is an effect that gear noise can be reduced with the above configuration.
[0046]
According to a fourth aspect of the present invention, in the power transmission device for a traveling work machine according to any one of the first to third aspects, the transmission case incorporating the planetary gear mechanism is connected to a rear axle case, A PTO shaft is provided at the rear end so that power is transmitted to the PTO shaft via the power shaft from the engine and the transmission shaft in the transmission case. The PTO shaft can be arranged coaxially with the sun gear shaft or on the left and right central axis of the traveling machine body.
[Brief description of the drawings]
FIG. 1 is a side view of a wheel loader as a traveling work machine.
FIG. 2 is a schematic plan view of a traveling machine body.
FIG. 3 is a skeleton diagram of a power transmission device configured by a hydraulic / mechanical transmission mechanism (HMT).
FIG. 4 is a partial cross-sectional view of the power transmission device.
5 is a VV arrow view of FIG. 3 when the transmission case of the power transmission device is viewed from the front of the traveling machine body.
FIG. 6 is an operation explanatory diagram of a power transmission device.
[Explanation of symbols]
2 traveling machine body 3, 4 front wheel, rear wheel 5 engine 7 power transmission device 8 rear wheel final reduction device 9 front wheel drive shaft 10 front wheel final reduction device 13 mission case 26 power shaft 30 planetary gear mechanism 31 hydraulic pump 32 hydraulic motors 33, 41 , 44, 50 to 53, 56, 57 Gear 34 Sun gear shaft 35, 45 Transmission gear 36 Carrier 37 Planetary gear 38 Sun gear 39 Inner ring gear 40 Outer ring gear 48 Counter shaft

Claims (4)

Power from the engine is transmitted to a planetary gear mechanism and a hydrostatic transmission including a variable hydraulic pump and a variable hydraulic motor, and the outputs of the hydrostatic transmission and the planetary gear mechanism are combined to change the speed. In the traveling work machine to be output,
The outer periphery of the rotatable sun gear shaft in the planetary gear mechanism is rotatably fitted with a carrier having a planetary gear and a ring gear meshing with the planetary gear,
Transmitting power from the engine to a gear provided on the outer periphery of the carrier;
While driving the variable hydraulic pump through the ring gear,
The power from the variable hydraulic motor is input to the sun gear shaft through a transmission gear,
A power transmission device for a traveling work machine, wherein power is transmitted from the sun gear shaft to a traveling unit. The power transmission device for a traveling work machine according to claim 1, wherein a sub-transmission mechanism is disposed between the sun gear shaft and the traveling unit. 3. The power transmission device for a traveling work machine according to claim 1, wherein a diameter of the transmission gear on the variable hydraulic motor side is set smaller than a transmission gear on the variable hydraulic pump side. While connecting the mission case containing the planetary gear mechanism to the rear axle case,
PTO shaft projecting from the rear end of the mission case,
4. The power in the traveling work machine according to claim 1, wherein power is transmitted to the PTO shaft via a power shaft from the engine and a transmission shaft in the transmission case. 5. Transmission device.

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