JP2005024027A - Hydraulic transmission, and working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the assembly efficiency in a hydraulic transmission to independently drive a pair of driving axles by each of a pair of hydraulic motor units. <P>SOLUTION: First and second motor units to cooperate with first and second pump units are connected to and supported by a common housing to support an input shaft in an upper area and support a pair of driving axles in a lower area from the outside. First and second transmission units to work-connect each motor shaft to the driving axles corresponding thereto having final gears symmetrically disposed in the right-to-left direction in the lower area in the housing while supported by the corresponding driving axles in a non-rotational manner are stored in the common housing. The lower area of the common housing is recessed in a center part of the width direction of a vehicle except a final gear storage unit to store the right and left final gears on the side close to an engine in the longitudinal direction of the vehicle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic transmission and a working vehicle capable of shifting transmission of driving force from a driving source to a pair of left and right driving axles.
[0002]
[Prior art]
A vehicle provided with an independent HST for each of a pair of left and right drive axles is known, for example, as described in Patent Document 1.
Such a vehicle can independently control the speed and / or rotational direction of the pair of left and right drive axles by independently shifting the pair of left and right HSTs, and is capable of turning performance, particularly small turns. There is an advantage of being suitable.
[0003]
However, the conventional configuration has room for improvement in terms of assembly efficiency.
That is, in the conventional vehicle, each of the pair of drive axles is supported by a corresponding separate reduction case. More specifically, the conventional vehicle includes a single power branching device that branches a driving force from a driving source, a pair of HSTs connected to the power branching device, and an operation connection to each of the pair of HSTs. And a pair of deceleration cases that support the corresponding drive axles.
[0004]
In such a configuration, the members forming the power transmission path must be operatively connected, and the housing of the power branching device, the housings of the pair of HSTs, and the housings of the pair of reduction cases must be connected and assembled. Therefore, there is a problem that the assembly efficiency is poor.
[0005]
[Patent Document 1]
JP 2000-71790 A
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in view of the prior art, and it is an object of the present invention to provide a hydraulic transmission that can improve assembly efficiency in a hydraulic transmission that independently drives a pair of drive axles by each of a pair of hydraulic motor units. To do.
Another object of the present invention is to improve assembly efficiency in a working vehicle configured to be capable of independently shifting transmission of driving force from an engine to a pair of left and right rear axles.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a hydraulic transmission capable of shifting transmission of driving force from an engine to a pair of left and right driving axles, the input shaft being operatively connected to the engine, An input shaft positioned above a pair of drive axles, a common housing that supports the input shaft in the upper region and supports the pair of left and right drive axles in the lower region, and is operatively connected to the input shaft. First and second pump units each having a pump shaft; and first and second motor units that cooperate with the first and second pump units to form first and second HSTs, respectively, the common housing First and second motor units connected and supported from the outside, motor shafts in the first and second motor units, and the corresponding drive vehicles And a first transmission unit housed in the common housing, and the first and second transmission units respectively correspond to each other. A final gear that is supported on the drive axle so as not to rotate relative to the drive axle, and has a final gear that is distributed to the left and right within a lower region of the common housing, and the lower region of the common housing is a vehicle front-rear direction. Provided is a hydraulic transmission in which a side close to the engine is recessed in a vehicle width direction central portion excluding a final gear housing portion for housing the left and right final gears.
In one aspect, the first and second pump units are connected and supported on the common housing from the outside.
In another aspect, the first and second pump units are connected and supported by the vehicle frame in a state where the pump shaft is operatively connected to the input shaft.
[0008]
Preferably, the common housing is an upper housing that forms the upper region, and an upper housing that is open at the bottom, and a lower housing that is detachably connected to the upper housing so as to form the lower region. And a lower housing having an upper opening.
[0009]
Preferably, in the various aspects, the hydraulic transmission may further include a PTO unit operatively connected to the input shaft in the common housing.
The PTO unit has a PTO shaft that extends outward from an end wall of the common housing in the vehicle front-rear direction end wall that is away from the engine.
[0010]
In order to achieve the above object, the present invention is a vehicle frame, an engine supported behind the vehicle frame in the longitudinal direction of the vehicle, and positioned in front of the engine in the longitudinal direction of the engine. An operatively coupled rotating body and a hydraulic transmission supported by the vehicle frame, wherein the hydraulic transmission capable of shifting transmission of driving force input from the engine via the rotating body to a pair of left and right rear axles A working vehicle equipped with is provided.
In the working vehicle, the hydraulic transmission is an input shaft operatively connected to the engine, and is an input shaft positioned above the pair of rear axles and a common housing supported by the vehicle frame. The first and second pumps each having a common housing that supports the input shaft in the upper region and supports the pair of left and right rear axles in the lower region, and a pump shaft that is operatively connected to the input shaft. A first and second motor unit that cooperate with the first and second pump units to form first and second HSTs, respectively, the first and second motor units connected to and supported by the common housing from the outside The second motor unit, the motor shaft in the first and second motor units, and the corresponding rear axle are operatively connected to each other. A first and a second transmission unit may include a first and second transmission unit housed within said common housing.
Each of the first and second transmission units is a final gear that is supported on the corresponding rear axle so as not to rotate relative to the rear axle, and has a final gear that is distributed to the left and right within a lower region of the common housing. In the lower region of the common housing, the rear side in the longitudinal direction of the vehicle is recessed at the center in the vehicle width direction excluding the final gear housing portion that houses the left and right final gears.
A part of the rotating body faces a recess in the lower region of the common housing.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of a hydraulic transmission according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a schematic side view of a working vehicle 500 to which the hydraulic transmission 1 according to the present embodiment is applied. 2 and 3 show a side view and a longitudinal side view of the hydraulic transmission 1, respectively. 4 and 5 are longitudinal rear views of the hydraulic transmission 1 along the line IV-IV in FIG. 1 and partial cross-sectional plan views of the hydraulic transmission 1 along the line V-V in FIG. 1, respectively. Show.
[0012]
The hydraulic transmission 1 according to the present embodiment is configured such that the driving force from the engine 510 can be independently transmitted to the pair of left and right drive axles 520.
Specifically, as shown in FIGS. 1 to 5, the hydraulic transmission 1 includes an input shaft 10 operatively connected to the engine 510, the input shaft 10, and the pair of drive axles 520. The common housing 20 rotatably supported, the first and second pump units 40a and 40b receiving the driving force from the input shaft 10, and the first and second pump units 40a and 40b are fluidly connected to each other. First and second hydraulic motor units 60a and 60b, and first and second hydraulically operatively connecting the first and second hydraulic motor units 60a and 60b and a corresponding drive axle of the pair of drive axles 520. And driven side transmission units 80a and 80b.
[0013]
As shown well in FIGS. 3 and 4, the input shaft 10 is supported by the common housing 20 so as to be positioned above the pair of drive axles 520.
That is, the common housing 20 supports the input shaft 10 in the upper region and supports the pair of drive axles 520 in the lower region.
[0014]
In the present embodiment, the common housing 20 includes an upper housing 21 having an opening on the lower side and a lower housing 31 having an opening on the upper side. The upper housing 21 and the lower housing 31 are mutually connected. It is connected so that attachment or detachment is possible at the opening end face.
The upper and lower housings 21 and 31 define the upper region and the lower region, respectively.
[0015]
More specifically, the upper housing 21 has a base portion 22 that closes an upper opening of the lower housing 31 and a bulging portion 23 that bulges upward from the base portion 22.
The bulging portion 23 is located on the side of the upper housing 21 that is separated from the engine 510.
[0016]
The bulging portion 23 is separated from the engine along the vehicle front-rear direction from the first end wall 23 a extending along the vehicle width direction so as to face the engine 510, and from both side edges of the first end wall 23 a. Left and right side walls 23b extending in the direction of the vehicle (in the illustrated form, the front direction of the vehicle, hereinafter referred to as the front direction) and the second end extending in the vehicle width direction so as to connect between the front end portions of the side walls 23b. It has an end wall 23c and an upper wall 23d that closes the upper ends of the first end wall 23a, the side wall 23b, and the second end wall 23c, and an upper housing space 21S is defined therein.
[0017]
The input shaft 10 is in a state in which an end portion on the side close to the engine 510 (a rear end portion in the illustrated form, hereinafter referred to as a rear end portion) extends outward, and the bulging portion 23 Is rotatably supported by the first end wall 23a.
In the present embodiment, the input shaft 10 also has an end portion (a front end portion in the illustrated embodiment, hereinafter referred to as a front end portion) on the side away from the engine 510 from the second end wall 23c. It extends outward and a charge pump 90 is supported at the front end.
FIG. 6 shows a hydraulic circuit diagram of the hydraulic transmission according to the present embodiment.
As shown in FIG. 6, the charge pump 90 supplies hydraulic oil to first and second HSTs 200a and 200b to be described later, and a hydraulic lift mechanism 300 for a PTO unit 150 to be described later and a work machine attached thereto.
[0018]
The lower housing 31 includes a bottom wall 31a, an end portion of the bottom wall 31a on the side close to the engine 510 (in the illustrated form, a rear end portion, hereinafter referred to as a rear end portion), and a separated side. A first end wall 31b and a second end wall 31c extending upward from an end portion (in the illustrated form, a front end portion, hereinafter referred to as a front end portion), respectively, and the first end wall 31b and the second end wall 31c. And a pair of side walls 31d extending in the vehicle front-rear direction so as to connect the opposite end portions of each other.
The pair of drive axles 520 are respectively supported by a pair of side walls 31d in the lower housing 31 so as to be rotatable about an axis.
The detailed structure of the lower housing 31 will be described later.
[0019]
As shown in FIG. 6, the first and second pump units 40a and 40b cooperate with the first and second motor units 60a and 60b to constitute the first and second HSTs 200a and 200b, respectively. It has become.
That is, the first pump unit 40a and the first hydraulic motor unit 60a are fluidly connected so as to form a closed circuit by the first oil passage 210a including piping and the like.
Similarly, the second pump unit 40b and the second hydraulic motor unit 60b are fluidly connected so as to form a closed circuit by a second oil passage 210b including piping and the like.
[0020]
At least one of the first pump unit 40a and the first motor unit 60a and at least one of the second pump unit 40b and the second motor unit 60b are variable displacement types.
In the present embodiment, the first and second pump units 40a, 40b have a movable swash plate, and a variable displacement type in which the suction / discharge amount changes by operating the movable swash plate, and The first and second motor units 60a and 60b are fixed displacement type.
[0021]
Here, the first pump unit 40a will be described.
The first and second pump units 40a and 40b have substantially the same configuration. Therefore, the following description regarding the first pump unit 40a also applies to the second pump unit 40b.
[0022]
FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.
As shown in FIG. 7, the first pump unit 40a includes a pump shaft 41 operatively connected to the input shaft 10, and a hydraulic pump body 50 driven by the pump shaft.
[0023]
The hydraulic pump body 50 rotates around the axis of the pump shaft 41 in accordance with the rotation of the pump shaft 41 and the center section 51 in which the oil holes forming a part of the first oil passage 210a are formed. A piston unit 52 that reciprocates in conjunction with the rotational motion, and supports the piston unit 52 so as to be reciprocally movable, and is slidably slidable on the center section 51 so as to communicate with the oil hole. An output adjustment member 54 (movable swash plate 55 and operation shaft 56 that controls the stroke length of the piston unit 52 by the supported cylinder block 53 and the tilt position and changes the amount of intake / discharge oil by the piston unit 52. And the piston unit 52, the cylinder block 53, and the movable swash plate 55 so as to surround the center. And a pump case 57 that is connected to the over section 51.
In the present embodiment, the hydraulic pump body 50 is an axial piston type, but may be a radial piston type.
[0024]
In the present embodiment, the first pump unit 40a can be connected and supported from the outside to the first end wall 23a of the bulging portion 23 of the upper housing 21.
Specifically, the pump case 57 is connected to the center section 51 so as to surround the piston unit 52, the cylinder block 53, and the movable swash plate 55, and is attached to and detached from the peripheral wall portion 57a. The end wall portion 57b is connected to the movable swash plate 55 so that the back surface side of the movable swash plate 55 is slidably contacted.
The end wall portion 57b is connected to the first end surface 23a of the bulging portion 23 so that the first pump unit 40a is connected to and supported by the bulging portion 23.
The end wall portion 57b is formed with an insertion hole through which the pump shaft 41 is inserted.
[0025]
As shown in FIGS. 4 and 7, in the present embodiment, the second pump unit 40b having the same configuration is also connected to and supported by the first end surface 23a of the bulging portion 23. We are trying to make effective use of dead space.
That is, as described above, the input shaft 10 is supported on the end surface (first end surface 23a) on the side close to the engine 510 in the bulging portion 23, and the input shaft 10 and the engine 510 are Usually, it is connected by a connecting shaft with a universal joint. Therefore, a dead space may be generated near the end of the input shaft 10 on the side close to the engine 510.
In the present embodiment, in view of such a viewpoint, the first and second pump units 40a and 40b are connected and supported by the first end face 23a.
[0026]
In the present embodiment, the first and second pump units 40a and 40b are juxtaposed in the vehicle width direction with the input shaft 10 in between (see FIGS. 4 and 6, etc.). Thus, one of the first and second pump units 40, 40b is supported on the first end surface 23a of the bulging portion 23, and the other of the first and second pump units 40a, 40b is the second of the bulging portion 23. It is also possible to support the end face 23c (see FIG. 8).
[0027]
That is, as described above, when the charge pump 90 driven by the front end portion of the input shaft 10 is supported by the second end surface 23b of the bulging portion 23, there is a dead space in the vicinity of the charge pump 90. Arise.
In the embodiment shown in FIG. 7, the first and second pump units 40a and 40b are distributed and arranged on the first and second end faces 23a and 23c of the bulging portion 23 from such a viewpoint. In this embodiment, the length in the vehicle longitudinal direction of the hydraulic transmission 1 is increased as compared with the present embodiment, but the length in the vehicle width direction can be shortened.
[0028]
Each pump shaft 41 in the first and second pump units 40a, 40b is operatively connected to the input shaft 10 via a drive side transmission unit 100 accommodated in the bulging portion 23, respectively. Yes.
Specifically, the hydraulic transmission 1 according to the present embodiment includes a common gear 101 that is supported by the input shaft 10 so as not to rotate relative to the input shaft 10 as the drive-side transmission unit 100, and a first gear that meshes with the common gear 101. 1 and 2nd transmission gear 101a, 101b, Comprising: The corresponding pump shaft 41 is provided with the 1st and 2nd transmission gear 101a, 101b connected so that relative rotation is impossible.
[0029]
In the present embodiment, the first and second transmission gears 101a and 101b are respectively mounted on the hollow shaft 102 supported by the first and second end surfaces 23a and 23c of the bulging portion 23 so as not to rotate relative to each other. The pump shafts 41 are inserted into and supported by the corresponding hollow shafts 102 so as not to rotate relative to each other.
By providing the drive side transmission unit 100 having such a configuration, the input shaft 10 and the drive side transmission unit 100 are assembled to the bulging portion 23, and then the first and second pump units 40 a and 40 b are The bulging portion 23 can be connected and supported from the outside, thereby improving the assemblability.
[0030]
The first and second hydraulic motor units 60a and 60b constituting the first and second HSTs 200a and 200b in cooperation with the first and second pump units 40a and 40b are respectively connected to the common housing 20 from the outside. It can be connected and supported.
In the present embodiment, the first and second hydraulic motor units 60 a and 60 b are respectively arranged on a pair of side walls 31 d of the lower housing 31 in the common housing 20.
[0031]
The first and second hydraulic motor units 60a and 60b are disposed on the side away from the engine 510 with respect to the longitudinal direction of the vehicle with respect to the pair of drive axles 520 (in the illustrated embodiment, forward). Yes.
That is, in the present embodiment, the first and second pump units 40a and 40b are driven by transmitting power from the engine 510 to the input shaft 10 located in front of the pair of drive axles 520 in the vehicle longitudinal direction. In addition, the first and second hydraulic motor units 60a and 60b driven by the first and second pump units 40a and 40b are positioned forward of the pair of drive axles 520 in the vehicle longitudinal direction.
Then, the power is transmitted from the first and second hydraulic motor units 60a and 60b to the pair of drive axles 520 backward in the vehicle longitudinal direction by the first and second driven side transmission units 80a and 80b described later in detail. ing.
[0032]
Here, the first hydraulic motor unit 60a will be described.
The second hydraulic motor unit 60b has substantially the same configuration as the first hydraulic motor unit 60a. Therefore, the following description regarding the first hydraulic motor unit 60a also applies to the second hydraulic motor unit 60b.
[0033]
As shown well in FIG. 5, the first hydraulic motor unit 60 a includes a hydraulic motor body 70 fluidly connected to the first hydraulic pump body 50, and a motor shaft 61 driven by the hydraulic motor body 70. And.
[0034]
The hydraulic motor main body 70 is supported by a center section 71 formed with an oil hole that constitutes a part of the first oil passage 210a, and rotatably supported by the center section so as to communicate with the oil hole. The cylinder block 72 reciprocates within the cylinder block 72 so as to reciprocate by the hydraulic pressure of the first oil passage and to perform a rotational motion that rotates the motor shaft 61 about the axis in conjunction with the reciprocation. A piston unit 73 that is freely and rotatably accommodated, a fixed swash plate 74 that defines a stroke length of the piston unit 73 according to a circumferential position around the motor shaft 61, the piston unit 73, and the cylinder block 72. And a motor case 75 connected to the center section 71 so as to surround the fixed swash plate 74.
[0035]
In the present embodiment, the center section 71 is connected to the side wall 31 d of the lower housing 31 from the outside, so that the first hydraulic motor unit 60 a is connected to and supported by the common housing 20. Of the outer surface of the side wall 31d, the motor connection surface to which the motor is connected is recessed toward the inside of the vehicle body from the axle support surface that supports the first drive axle 520a. The hydraulic motor unit 60a can be comfortably stored inside the body frame 600 in a sideways state (see FIG. 5).
One end of the motor shaft 61 passes through the center section 71 and faces the lower housing 31 and is connected to the driven transmission unit 80a via the one end (inner end).
[0036]
In the present embodiment, the first hydraulic motor unit 60 a further includes a brake unit 65 that applies a braking force to the motor shaft 61.
Specifically, the other end portion (outer end portion) of the motor shaft 61 extends outward from the motor case 75.
The brake unit 65 can selectively apply a braking force to the outer end portion of the motor shaft 61 based on an external operation.
In the illustrated embodiment, a mechanical friction brake mechanism is employed as the brake unit 65.
[0037]
Next, the first driven side transmission unit 80a will be described.
The second driven side transmission unit 80b has substantially the same configuration as the first driven side transmission unit 80a. Therefore, the following description regarding the first driven side transmission unit 80a also applies to the second driven side transmission unit 80b.
[0038]
The first driven side transmission unit 80a transmits a reduced speed between the motor shaft 61 of the first hydraulic motor unit 60a and the first drive axle 520a, and the corresponding side wall 31d (first The motor shaft 61 is accommodated in the lower housing 31 along the rear side of the vehicle from the motor shaft 61 to the first drive axle 520a.
That is, both the first driven side unit 90a and the second driven side unit 80b are arranged so that power can be transmitted from the motor shaft 61 to the corresponding drive axle 520 along the side wall 31d of the lower housing 31 in the vehicle longitudinal direction rearward. Thus, a free space is formed in the central region of the lower housing 31 in the vehicle width direction.
[0039]
Specifically, the first driven side transmission unit 80a includes a first reduction gear train 81 connected to the motor shaft 61, and a second reduction gear train 85 connected to the first reduction gear train 81, And a second reduction gear train 85 having a final gear coupled to the first drive axle 520a so as not to be relatively rotatable.
[0040]
In the present embodiment, the first reduction gear train 81 includes a first small gear 82 that is extrapolated to the inner end portion of the motor shaft 61 so as not to be relatively rotatable, and a first large gear that meshes with the first small gear 82. And a gear 83.
The first small gear 82 has a hollow shaft portion 82a into which the motor shaft 61 is inserted so as not to be relatively rotatable, and a gear portion 82b provided on the outer surface of the hollow shaft portion 82a.
The hollow shaft portion 82a is rotatably supported by the first side wall 31d and a rib 31e provided on the bottom wall 31a so as to be positioned in the vicinity of the first side wall 31d.
The first large gear 83 is supported by an idle shaft 84 disposed between the motor shaft 61 and the first drive axle 520a so as not to be relatively rotatable along the vehicle width direction.
The idle shaft 84 is rotatably supported by the first side wall 31d and a rib 31f provided on the bottom wall 31a so as to be positioned in the vicinity of the first side wall 31d.
[0041]
The second reduction gear train 85 includes a second small gear 86 provided on the outer surface of the idle shaft 84, and the final gear 87 that meshes with the second small gear 86.
In the illustrated embodiment, the final gear 87 is supported by the side wall 31d of the lower housing 31 so as to be relatively rotatable while being supported by the first drive axle 520a so as not to be relatively rotated.
Specifically, an opening for engaging with the final gear 87 through the first drive axle 520a is provided on a drive axle support surface that supports the first drive axle 5201 in the side wall 31d of the lower housing 31. Yes. A cylindrical axle housing 530a for closing the opening is mounted on the outer surface of the side wall 31d. An axle hub is provided at the outer end of the first drive axle 520a extending outward from the outer end of the axle housing 530a, and the drive wheel is attached to the axle hub. The axle housing 530a is connected and supported to the body frame 600 by a support member 535 such as a U-bolt at a substantially central portion in the longitudinal direction (vehicle width direction).
[0042]
Here, the structure of the lower housing 31 will be described.
As described above, the lower housing 31 supports the first hydraulic motor unit 60a and the first drive axle 520a arranged such that one of the side walls 31d is along the vehicle longitudinal direction, and the other side of the side wall 31d is The second hydraulic motor unit 60b and the second drive axle 520b disposed along the vehicle longitudinal direction are supported.
The lower housing 31 accommodates a first driven side transmission unit 80a that transmits a reduced speed between the first hydraulic motor unit 60a and the first drive axle 520a in the vicinity of the one side wall 31d, and the second housing 31a. The second driven side transmission unit 80b that transmits the deceleration between the hydraulic motor unit 60b and the second drive axle 520b is accommodated in the vicinity of the other side wall 31d.
[0043]
The lower housing 31 having such a configuration further excludes a final gear accommodating portion that accommodates the left and right final gears 87 on the side close to the engine 510 in the longitudinal direction of the vehicle (the rear end side in the illustrated form). It is comprised so that it may dent in the vehicle width direction center part.
That is, the lower housing 31 is substantially in the vehicle width direction of the first end wall 31b so that the rear end side in the free space between the first and second driven side transmission units 80a and 80b is recessed in plan view. The central region 31b ′ is recessed, thereby shortening the longitudinal distance between the engine 520 and the hydraulic transmission 1 (see FIG. 1).
[0044]
More specifically, as shown in FIG. 1, the engine 510 is of a horizontal crankshaft type. The engine 510 is supported by the body frame 600 in an anti-vibration manner with a crankshaft (not shown) along the longitudinal direction of the vehicle. The crank shaft of the engine 510 has both ends in the vehicle front-rear direction extending outward from the front and rear surfaces of the cylinder block, and a rotating body is connected to each of the outer extended portions.
Note that the rotating body includes, for example, a radiator unit (see FIG. 1) such as a fan drive pulley 516 for sending cooling air to the radiator, and a flywheel 510 (see FIG. 1). In the illustrated embodiment, the flywheel 510 is disposed in front of the vehicle, that is, on the hydraulic transmission 1 side.
In such a configuration, the flywheel 515 connected to the output portion of the engine 510 can face the concave portion 31b ′ of the lower housing 31, whereby the engine 510 and the hydraulic transmission 1 are arranged closer to each other. can do. Also, the universal joint shaft for connecting the input shaft 10 and the flywheel 510 may be short.
When the fan drive pulley 516 is disposed in front of the vehicle, that is, on the hydraulic transmission 1 side, a radiator unit such as the fan drive pulley 516 is allowed to face the recess 31b ′ of the lower housing 31 to thereby Similarly, the engine 510 and the hydraulic transmission 1 can be arranged closer to each other.
[0045]
The hydraulic transmission 1 according to the present embodiment further includes a PTO unit 150 operatively connected to the input shaft 10 in addition to the above configuration.
The PTO unit 150 is accommodated in the free space in the lower housing 31, thereby making effective use of the space.
[0046]
Specifically, the PTO unit 150 includes a PTO shaft 160, a hydraulic clutch mechanism 170, and a PTO transmission unit 180 that operatively connects the hydraulic clutch mechanism 170 and the input shaft 10.
The PTO shaft 160 is supported by the lower housing 31 so that the output end portion protrudes to the side away from the engine 510.
[0047]
The hydraulic clutch mechanism 170 is a friction clutch type configured to be able to engage / shut off power transmission from the input shaft 10 to the PTO shaft 160 by the pressure oil action of hydraulic oil.
That is, the hydraulic clutch mechanism 170 includes a driving side member 171 operatively connected to the input shaft 10 via the PTO transmission unit 180, a driven side member 172 supported on the PTO shaft 160 so as not to be relatively rotatable, It has a friction transmission member 173 such as a friction plate that controls transmission / cutoff of power between the driving side member 171 and the driven side member 172, and is controlled by controlling supply of hydraulic oil to the friction transmission member 173. The power transmission from the side member 171 to the driven side member 172 can be selectively engaged / cut off.
[0048]
Preferably, the PTO unit 150 may be provided with a hydraulic brake mechanism 190 that releases / adds a braking force to the PTO shaft 160 in conjunction with the hydraulic clutch mechanism 170 by a pressure oil action of hydraulic oil.
The hydraulic brake mechanism 190 releases the braking force to the PTO shaft 160 when the hydraulic clutch mechanism 170 is in a power transmission state, and the hydraulic clutch mechanism 170 is in a power transmission release state. In some cases, a braking force is applied to the PTO shaft 160.
In the present embodiment, as shown in FIG. 6, hydraulic oil to the hydraulic clutch mechanism 170 and the hydraulic brake mechanism 190 is supplied by the charge pump 90.
[0049]
The hydraulic clutch mechanism 170 and the hydraulic brake mechanism 190 are accommodated in a front region of the lower housing 31.
More specifically, the lower housing 31 is a box-shaped accommodation space in which the front 32a and the upper 32b are opened at the front in the vehicle front-rear direction and the vehicle width direction, and both the side 32c and the rear 32d are surrounded by walls. 32.
The hydraulic clutch mechanism 170 and the hydraulic brake mechanism 190 can be installed in the accommodation space 32 of the lower housing 31 from the front opening 32a (see FIGS. 3 and 4).
The front opening 32a is closed by a lid member 35 that is detachably attached to the lower housing 31, and the PTO shaft 160 has the front end portion extended outward from the lid member 35. Both ends are supported by the lid member 35 and the rear wall portion 32d.
3 is a pipe that communicates the charge pump 90 with the hydraulic oil supply hole 161 for the hydraulic clutch mechanism 170 and the hydraulic brake mechanism 190 that are drilled in the PTO shaft 160.
[0050]
The PTO transmission unit 180 includes a PTO transmission gear 181 that meshes with both the common gear 101 and the driving side member 171, a PTO intermediate shaft 182 that supports the PTO transmission gear 181, and both ends of the PTO intermediate shaft 182. And a support member 183 that rotatably supports.
The support member 183 is detachably installed on the upper surfaces of the pair of side wall portions 32c that define the box-shaped accommodation space 32 (see FIG. 4).
[0051]
In the present embodiment, the lowermost end portion of the PTO transmission gear 181 is configured to be positioned below the lower surface of the support member 183, thereby improving the assembling workability of the PTO unit 150. Yes.
That is, by configuring the lowermost end portion of the PTO transmission gear 181 below the lower surface of the support member 183, the hydraulic clutch mechanism 170 is assembled after the PTO transmission unit 180 is assembled to the lower housing 31. And by inserting the hydraulic brake mechanism 190 into the accommodation space 32 from the front opening 32a, the drive side member 171 of the hydraulic clutch mechanism 170 and the PTO transmission gear 181 can be engaged with each other. Assembling workability is improved.
[0052]
【The invention's effect】
As described above, according to the hydraulic transmission and the working vehicle according to the present invention, the pair of left and right driving axles to which the driving force from the engine is independently transmitted and shifted are configured to be supported by the common housing. Can be improved. Further, since the side of the common housing that is close to the engine is recessed at the substantially center in the vehicle width direction, the engine and the hydraulic transmission can be brought closer to each other.
[Brief description of the drawings]
FIG. 1 is a side view of a working vehicle to which a hydraulic transmission according to an embodiment of the present invention is applied.
FIG. 2 is a side view of the hydraulic transmission shown in FIG.
FIG. 3 is a vertical side view of the hydraulic transmission shown in FIGS. 1 and 2;
4 is a longitudinal rear view of the hydraulic transmission along the line IV-IV in FIG. 1. FIG.
FIG. 5 is a partial cross-sectional plan view of the hydraulic transmission taken along line VV in FIG. 1;
FIG. 6 is a hydraulic circuit diagram of the hydraulic transmission shown in FIGS. 1 to 5;
7 is a cross-sectional view taken along line VII-VII in FIG. 4, and is a cross-sectional plan view in the vicinity of a pump unit in the hydraulic transmission.
FIG. 8 is a cross-sectional plan view of the vicinity of a hydraulic transmission in a modified example of the hydraulic transmission.
[Explanation of symbols]
1 Hydraulic transmission
10 Input shaft
20 Common housing
21 Upper housing
31 Lower housing
40a First pump unit
40b Second pump unit
41 Pump shaft
60a First motor unit
60b Second motor unit
61 Motor shaft
80a First driven side transmission unit
80b Second driven side transmission unit
87 Final Gear
150 PTO unit
160 PTO axis
200a 1st HST
200b 2nd HST
500 working vehicle
510 engine
515 flywheel

Claims (5)

A hydraulic transmission capable of shifting transmission of driving force from an engine to a pair of left and right drive axles,
An input shaft operatively connected to the engine, the input shaft positioned above the pair of drive axles;
A common housing that supports the input shaft in an upper region and supports the pair of left and right drive axles in a lower region;
First and second pump units each having a pump shaft operatively connected to the input shaft;
First and second motor units that cooperate with the first and second pump units to form first and second HSTs, respectively, and are coupled and supported from the outside to the common housing. Unit,
1st and 2nd transmission unit which operatively connects the motor shaft in said 1st and 2nd motor unit, and the said corresponding drive axle, respectively, Comprising: The 1st and 2nd transmission unit accommodated in the said common housing And
Each of the first and second transmission units is a final gear that is supported on the corresponding drive axle so as not to be relatively rotatable, and has a final gear that is distributed to the left and right within a lower region of the common housing. ,
The hydraulic transmission is characterized in that a lower region of the common housing is recessed in a vehicle width direction central portion excluding a final gear housing portion that houses the left and right final gears in a vehicle front-rear direction that is close to the engine. . 2. The hydraulic transmission according to claim 1, wherein the first and second pump units are configured to be connected and supported to the common housing from the outside. The common housing is an upper housing that forms the upper region, an upper housing that is open at the bottom, and a lower housing that is detachably connected to the upper housing so as to form the lower region. The hydraulic transmission according to claim 1, further comprising a lower housing having an upper opening. A PTO unit operably coupled to the input shaft further within the common housing;
The said PTO unit has the PTO shaft extended outward from the end wall in the side in the vehicle front-back direction in the said common housing in the side spaced apart from the said engine. A hydraulic transmission according to any one of the above. A vehicle frame,
An engine supported behind the vehicle frame in the longitudinal direction of the vehicle;
A rotating body located forward in the vehicle longitudinal direction of the engine and operatively connected to the output of the engine;
A hydraulic transmission supported by the vehicle frame, comprising a hydraulic transmission capable of shifting transmission of driving force input from the engine via the rotating body to a pair of left and right rear axles;
The hydraulic transmission is
An input shaft operatively connected to the engine, the input shaft positioned above the pair of rear axles;
A common housing supported by the vehicle frame, supporting the input shaft in an upper region and supporting the pair of left and right rear axles in a lower region;
First and second pump units each having a pump shaft operatively connected to the input shaft;
First and second motor units that cooperate with the first and second pump units to form first and second HSTs, respectively, and are coupled and supported from the outside to the common housing. Unit,
1st and 2nd transmission unit which operatively connects the motor shaft in said 1st and 2nd motor unit, and the corresponding said rear axle, respectively, Comprising: The 1st and 2nd transmission unit accommodated in the said common housing And
Each of the first and second transmission units is a final gear that is supported on the corresponding rear axle so as not to rotate relative to the rear axle, and has a final gear that is distributed to the left and right within a lower region of the common housing. ,
The lower region of the common housing is recessed at the vehicle longitudinal direction rear side in the vehicle width direction central portion excluding the final gear housing portion for housing the left and right final gears,
A working vehicle, wherein a part of the rotating body faces a recess in a lower region of the common housing.

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