JP2022185268A - Working vehicle - Google Patents

Abstract

To provide a working vehicle configured so that sufficient lubricating-oil is held inside a gear change case even when a machine body (transmission case and gear change case) is largely inclined, while including a configuration of removing air inside the gear change case.SOLUTION: A working vehicle includes: a transmission case 20 for storing a transmission shaft 40 to which the power of a prime mover part 4 is transmitted; a continuously variable transmission 32 having a hydraulic pump 35 and a hydraulic motor 36 to which the power of the transmission shaft 40 is transmitted; a gear change case 21 connected to the transmission case 20 and storing the continuously variable transmission 32; a charge pump 48 capable of supplying lubricating-oil stored in the transmission case 20 as working fluid to the continuously variable transmission 32; and contraction passages 56, 57 disposed over the transmission case 20 and the gear change case 21, allowing passing of air over the inside of the transmission case 20 and the inside of the gear change case 21, and giving resistance against passing of lubricating-oil.SELECTED DRAWING: Figure 6

Description

The present invention relates to a working vehicle equipped with a hydrostatic continuously variable transmission as a transmission for running.

In a lawn mower, which is an example of a work vehicle, as disclosed in Patent Document 1, the power of an engine (corresponding to a prime mover) is transmitted to a transmission shaft, and the power of the transmission shaft is transferred to a hydrostatic continuously variable transmission. In some cases, the power is transmitted to a hydraulic pump, and the power of the hydraulic motor of the continuously variable transmission is transmitted to wheels for running (corresponding to a running device).

In Patent Document 1, a transmission shaft through which power of an engine is transmitted is housed in a transmission case, a continuously variable transmission is housed in a transmission case, and the transmission case and the transmission case are connected. Lubricating oil stored in the transmission case is supplied to the continuously variable transmission as working oil by a charge pump.

JP 2013-108525 A

When lubricating oil is supplied to the continuously variable transmission as hydraulic oil by the charge pump, the lubricating oil leaks into the transmission case from the hydraulic pump and hydraulic motor of the continuously variable transmission, causing the air inside the transmission case to leak. It is necessary to have a configuration to pull out.

When the work vehicle travels on a slope for work, the machine body tilts greatly, and the transmission case and the transmission case also tilt greatly. This is important in terms of improving the durability of the stepped transmission.

The present invention provides a working vehicle having a configuration for removing air from the inside of a gear shift case, so that sufficient lubricating oil is retained inside the gear shift case even if the machine body (the transmission case and the gear shift case) is greatly inclined. It is intended to configure

The work vehicle of the present invention is a hydrostatic stepless stepless vehicle having a transmission case that houses a transmission shaft to which the power of a prime mover is transmitted, a hydraulic pump to which the power of the transmission shaft is transmitted, and a hydraulic motor that outputs the power. A transmission, a transmission case that is connected to the transmission case and houses the continuously variable transmission, and a traveling device that is driven by transmission of the power of the hydraulic motor, and lubrication stored in the transmission case. A charge pump capable of supplying oil as hydraulic oil to the continuously variable transmission, and a passage of air between the transmission case and the transmission case, and passing air between the inside of the transmission case and the transmission case. and a throttle passage that resists the passage of lubricating oil.

According to the present invention, in a configuration in which a transmission case accommodating a transmission shaft to which power of a driving portion is transmitted and a transmission case accommodating a continuously variable transmission are connected, a throttle passage extends between the transmission case and the transmission case. are provided.
As a result, when lubricating oil stored in the transmission case is supplied to the continuously variable transmission as working oil by the charge pump, the lubricating oil leaks into the transmission case from the hydraulic pump and hydraulic motor of the continuously variable transmission. Along with this, the air inside the transmission case passes through the throttle passage and escapes to the transmission case.

In addition, since the throttle passage is configured to give resistance to the passage of the lubricating oil, as described above, the machine body (the transmission case and the transmission case) is greatly inclined, and the oil level of the lubricating oil inside the transmission case is lowered. Even when the lubricating oil reaches the throttle passage, the lubricating oil is prevented from flowing from the transmission case to the transmission case in the throttle passage.
As a result, even if the machine body (the transmission case and the transmission case) is greatly inclined, it is possible to suppress the reduction of the lubricating oil in the transmission case. Sufficient lubricating oil is retained inside the transmission case due to internal leakage of the lubricating oil.

As described above, according to the present invention, the air inside the transmission case can be released by providing the throttle passage through which air can pass and which resists the passage of lubricating oil across the transmission case and the transmission case. In addition, even if the machine body (transmission case and transmission case) is greatly inclined, sufficient lubricating oil can be retained inside the transmission case, and the durability of the continuously variable transmission can be improved. .

In the present invention, it is preferable that the hydraulic pump is arranged at a position higher than the hydraulic motor, and the throttle passage is arranged at a position higher than the hydraulic motor.

According to the present invention, the throttle passage is arranged at a relatively high position in the transmission case. As a result, even if the machine body (transmission case and speed change case) is greatly inclined, the oil surface of the lubricating oil inside the speed change case does not easily reach the throttle passage, thereby suppressing the flow of lubricating oil from the speed change case to the transmission case. This is advantageous in terms of retaining sufficient lubricating oil inside the transmission case.

In the present invention, an input shaft that supports the hydraulic pump, is rotatably supported by the speed change case, and is connected to the transmission shaft; and a bearing attached to a case, and the throttle passage is provided in a mounting surface portion of the transmission case to which the outer race of the bearing is attached, extending through the inside of the transmission case and the inside of the transmission case. It is suitable in it being a groove part.

In the work vehicle, in the continuously variable transmission, the input shaft supporting the hydraulic pump is rotatably supported by the transmission case, the input shaft and the transmission shaft of the transmission case are connected, and the transmission shaft connects the input shaft and the hydraulic pump. It may be configured to be rotationally driven.

According to the present invention, in the bearing attached to the transmission case so as to be able to support the transmission shaft side portion of the input shaft, the inside of the transmission case and the inside of the transmission case are attached to the mounting surface portion of the transmission case to which the outer race of the bearing is attached. A groove as a throttle passage is provided along the .
As a result, the throttle passage can be obtained by a simple process of providing a groove in the existing portion of the transmission case mounting surface where the outer race of the bearing is mounted, which is advantageous in terms of structural simplification and cost reduction. is.

In the present invention, it is preferable that a stopper ring for stopping the outer race is attached to the speed change case, and the stopper ring enters the groove to reduce the opening area of the groove.

When the outer race of the bearing is attached to the mounting surface of the transmission case, a stopper ring that stops the outer race of the bearing is sometimes attached to the transmission case, and the stopper ring is attached along the mounting surface of the transmission case.

According to the present invention, by inserting the stopper ring into the groove so as to intersect with the groove, even if the groove has a relatively large cross-sectional area, the existing member of the stopper ring can be effectively used to reduce the cross-sectional area of the groove. This is advantageous in terms of structural simplification because it is possible to easily reduce the size of a portion and to easily obtain a throttle passage.

In the present invention, an axle case is provided which is connected to the transmission case, has an axle for driving the traveling device, and accommodates a transmission system for transmitting the power of the hydraulic motor to the axle, the transmission case and the axle. a first passage provided across the case and through which lubricating oil can pass through the inside of the transmission case and the inside of the axle case; and the transmission case provided across the transmission case and the axle case. Preferably, a second passage is provided through which lubricating oil can pass through the interior of the case and the interior of the axle case.

In a work vehicle, an axle case having an axle for driving a travel device is connected to a transmission case, and power of a hydraulic motor of a continuously variable transmission in the transmission case is transmitted to the axle via a transmission system inside the axle case. may be configured as

According to the present invention, in the configuration described above, the first passageway is provided between the transmission case and the axle case, and the second passageway is provided between the transmission case and the axle case.
As a result, the lubricating oil stored in the transmission case is supplied to the continuously variable transmission as working oil by the charge pump, and the lubricating oil leaks from the hydraulic pump and hydraulic motor of the continuously variable transmission to the inside of the transmission case. Lubricant flow can be expected to occur such that case lubricant enters the interior of the axle case through the first passage and axle case lubricant returns to the transmission case through the second passage.
Since the cooling of the lubricating oil is promoted by generating such a flow of the lubricating oil, it is advantageous in terms of preventing deterioration of the lubricating oil.

In the present invention, it is preferable that the first passage is a through hole formed in a wall partitioning the transmission case and the axle case and extending through the inside of the transmission case and the inside of the axle case. .

According to the present invention, the first passage can be obtained by opening the through hole in the wall portion that partitions the transmission case and the axle case, which is advantageous in terms of structural simplification.

In the present invention, it is preferable that the through hole is opened in a portion of the wall portion between the hydraulic pump and the hydraulic motor.

The portion between the hydraulic pump and the hydraulic motor of the continuously variable transmission is located near the lubricating oil leaking from both the hydraulic pump and the hydraulic motor of the continuously variable transmission, and is located substantially in the center inside the transmission case. .
According to the present invention, since the through-hole is provided between the hydraulic pump and the hydraulic motor, lubricating oil in the transmission case can easily enter the through-hole, so that the lubricating oil can flow from the transmission case to the axle case. advantage in terms of

In the present invention, the second passage is a pipe member connected across the transmission case and the axle case, and a portion of the pipe member connected to the transmission case is a portion of the pipe member connected to the axle case. is preferably located at a position lower than the connecting portion of the .

According to the present invention, when the pipe member is provided as the second passage, the connection portion of the pipe member with the transmission case is arranged at a position lower than the connection portion of the pipe member with the axle case, thereby lubricating oil flows into the axle case through the tubular member.
As a result, the lubricating oil in the transmission case enters the inside of the axle case through the first passage, and the lubricating oil in the axle case returns to the transmission case through the second passage. is advantageous.

In the present invention, it is preferable that a portion of the pipe member connected to the transmission case is arranged at a position lower than the oil level of lubricating oil stored in the transmission case.

According to the present invention, since the connecting portion of the pipe member with the transmission case is arranged at a position lower than the oil surface of the lubricating oil stored in the transmission case, lubricating oil returns from the pipe member to the transmission case. In addition, less air bubbles enter the lubricating oil in the transmission case.
This makes it difficult for air bubbles to enter the continuously variable transmission when the lubricating oil stored in the transmission case is supplied to the continuously variable transmission as working oil by the charge pump. Malfunctions of the continuously variable transmission can be reduced.

The work vehicle of the present invention is a hydrostatic stepless stepless vehicle having a transmission case that houses a transmission shaft to which the power of a prime mover is transmitted, a hydraulic pump to which the power of the transmission shaft is transmitted, and a hydraulic motor that outputs the power. a transmission, a transmission case connected to the transmission case to accommodate the continuously variable transmission, a travel device, and an axle connected to the transmission case to drive the travel device; to the axle, a charge pump capable of supplying lubricating oil stored in the transmission case to the continuously variable transmission as hydraulic oil; the transmission case and the a throttle passage provided across the transmission case and allowing air to pass through the interior of the transmission case and the interior of the transmission case and providing resistance to the passage of lubricating oil; the transmission case and the axle case; a first passage provided over the transmission case and the inside of the axle case through which lubricating oil can pass; and a first passage provided over the transmission case and the axle case, A second passage is provided for passage of lubricating oil through the interior and the interior of the axle case.

According to the present invention, in a configuration in which a transmission case accommodating a transmission shaft to which power of a driving portion is transmitted and a transmission case accommodating a continuously variable transmission are connected, a throttle passage extends between the transmission case and the transmission case. are provided.
As a result, when lubricating oil stored in the transmission case is supplied to the continuously variable transmission as working oil by the charge pump, the lubricating oil leaks into the transmission case from the hydraulic pump and hydraulic motor of the continuously variable transmission. Along with this, the air inside the transmission case passes through the throttle passage and escapes to the transmission case.

In the configuration described above, when the work vehicle travels on a slope for work, the machine body (the transmission case and the transmission case) is greatly inclined, and when the oil level of the lubricating oil inside the transmission case reaches the throttle passage. , the lubricating oil in the transmission case flows into the transmission case through the throttle passage, and the lubricating oil in the transmission case may temporarily decrease.

According to the present invention, the throttle passage is configured to give resistance to the passage of lubricating oil, so that the machine body (the transmission case and the transmission case) is greatly inclined as described above, and the lubricating oil inside the transmission case is dissipated. Even if the oil surface reaches the throttle passage, the flow of lubricating oil from the transmission case to the transmission case is suppressed in the throttle passage.
As a result, even if the machine body (the transmission case and the transmission case) is greatly inclined, it is possible to suppress the reduction of the lubricating oil in the transmission case. Sufficient lubricating oil is retained inside the transmission case due to internal leakage of the lubricating oil.

As described above, according to the present invention, by providing the throttle passage through the transmission case and the transmission case, which allows passage of air and provides resistance to the passage of lubricating oil, the air inside the transmission case is released. Even if the machine body (transmission case and transmission case) is greatly inclined, sufficient lubricating oil can be retained inside the transmission case, and the durability of the continuously variable transmission can be improved.

In a work vehicle, an axle case having an axle for driving a travel device is connected to a transmission case, and power of a hydraulic motor of a continuously variable transmission in the transmission case is transmitted to the axle via a transmission system inside the axle case. may be configured as

According to the present invention, in the configuration described above, the first passageway is provided between the transmission case and the axle case, and the second passageway is provided between the transmission case and the axle case.
As a result, the lubricating oil stored in the transmission case is supplied to the continuously variable transmission as working oil by the charge pump, and the lubricating oil leaks from the hydraulic pump and hydraulic motor of the continuously variable transmission to the inside of the transmission case. Lubricant flow can be expected to occur such that case lubricant enters the interior of the axle case through the first passage and axle case lubricant returns to the transmission case through the second passage.
Since the cooling of the lubricating oil is promoted by generating such a flow of the lubricating oil, it is advantageous in terms of preventing deterioration of the lubricating oil.

It is a right side view of a mower. It is a top view of a mower. It is a longitudinal right side view near the airframe. It is a cross-sectional plan view of the airframe vicinity. It is a schematic diagram showing a transmission system from an engine to a transmission case, left and right transmission cases, left and right axle cases, and a mowing device. FIG. 2 is a schematic diagram showing hydraulic systems of a transmission case, left and right transmission cases, left and right continuously variable transmissions, and left and right axle cases; 3 is a plan view of a transmission case, left and right transmission cases, and left and right axle cases; FIG. 4 is a front view of a transmission case, left and right transmission cases, and left and right axle cases; FIG. FIG. 4 is a rear view of the transmission case, left and right transmission cases, and left and right axle cases; It is a vertical rear view of a transmission case, a transmission case on either side, and an axle case on either side. FIG. 11 is a cross-sectional view seen from the XI-XI direction in FIG. 10; FIG. 12 is a cross-sectional view viewed from the XII-XII direction in FIG. 11;

1 to 12 show a remote-controlled mower, which is an example of a work vehicle. In FIGS. 1 to 12, F indicates the forward direction, B indicates the rearward direction, and U indicates the upward direction. , D indicates downward, R indicates rightward, and L indicates leftward.

(Overall Configuration of Mower)
As shown in FIGS. 1 to 4, a machine body 1 is supported by left and right crawler-type traveling devices 2, a mowing device 3 as a working device is supported on the front part of the machine body 1, and an engine 4 is mounted on the rear part of the machine body 1. (corresponding to the driving portion) are supported, and the transmission case 20, the left and right transmission cases 21, and the left and right axle cases 22 are connected to the machine body 1 to form the entire mower.

Vertical left and right frames 9, vertical left and right frames 10, horizontal front and rear frames 11, and front and rear left and right frames 12 are connected in a square frame shape. The left and right track frames 17 are connected to the lower portions of the frames 9 and 10 , and the front and rear frames 5 and 6 along the left-right direction are connected over the track frames 17 . As described above, the body 1 has the frames 5, 6, 9 to 12, the track frame 17, and the like.

The traveling device 2 has four rollers 16 supported by a track frame 17, a driving wheel 15 supported by an axle case 22, and a crawler belt 19 attached to the driving wheels 15 and the rollers 16. ing.

(Construction of transmission case, speed change case and axle case)
As shown in FIGS. 7 to 10, the transmission case 20 is arranged in the left-right center A1 (see FIG. 4) of the machine body 1, and the transmission case 20 is provided with left and right transmission cases 21 and left and right axle cases 22. is provided.

The transmission case 21 is configured by connecting a housing case 23 to a flat port block 24 (corresponding to a wall portion). The port block 24 is configured to be longer than the housing case 23 , and the housing case 23 is connected to the front portion (upper portion) of the port block 24 so that the rear portion (lower portion) of the port block 24 is separated from the housing case 23 . It is behind (downward).

The right transmission case 21 (accommodating case 23) is connected to the upper right lateral side of the transmission case 20, and the left transmission case 21 (accommodating case 23) is connected to the upper left lateral side of the transmission case 20. connected to the sides. Port blocks 24 are positioned laterally outside the storage case 23 on the left and right shift cases 21 .

The right axle case 22 is connected to the rear (lower portion) of the right lateral side of the right transmission case 21 (port block 24), and the port block 24 of the right transmission case 21 is connected to the right transmission case 21. and the right axle case 22. A front portion (upper portion) of the port block 24 of the right transmission case 21 protrudes forward (upward) from the right axle case 22 .

The left axle case 22 is connected to the rear (lower portion) of the left lateral side of the left shift case 21 (port block 24), and the port block 24 of the left shift case 21 is connected to the left shift case 21. and the left axle case 22. A front portion (upper portion) of the port block 24 of the left transmission case 21 protrudes forward (upward) from the left axle case 22 .

(Construction of connection between transmission case, left and right shift cases, left and right axle cases, and machine body)
As shown in FIGS. 1 and 4 , the left and right connecting brackets 13 are connected to portions of the track frame 17 between the front and rear frames 5 and 6 and extend toward the left-right center A1 of the fuselage 1 . Left and right connection brackets 14 are connected to the connection bracket 13 and extend upward. Left and right connecting brackets 30 are connected to portions of the frame 9 between the track frame 17 and the frame 11 and extend obliquely rearward and downward.

A portion of the rear portion (lower portion) of the port block 24 of the right transmission case 21 on the side of the left-right center A1 of the airframe 1 is connected to the right connection bracket 14, and the rear portion (lower portion) of the port block 24 of the left transmission case 21 ( lower part) is connected to the left connecting bracket 14 on the left-right center A1 side of the fuselage 1 .

The right lateral side of the front (upper) portion of the port block 24 of the right shift case 21 is connected to the right connecting bracket 30, and the front (upper) portion of the port block 24 of the left shift case 21 is connected to the right side. The left lateral side is connected to the left connecting bracket 30 .

With the above configuration, the transmission case 20, the left and right transmission cases 21, and the left and right axle cases 22 are arranged along the left-right direction of the machine body 1 in plan view, and the transmission case 20 is in the left-right center of the machine body 1 in plan view. Located in A1.

As viewed from the side, the transmission case 21 extends obliquely downward and rearward from the upper portion of the transmission case 20, and the front portion of the transmission case 21 (accommodating case 23) extends downward when the travel device 2 is in contact with the horizontal plane. , is arranged at a position higher than the rear portion of the transmission case 21 (accommodating case 23).

In a side view, the axle case 22 is in a posture extending obliquely rearward and downward, and the front part of the axle case 22 is higher than the rear part of the axle case 22 when the traveling device 2 is in contact with the horizontal surface. placed in position.

(Configuration of transmission system from engine to transmission case)
As shown in FIGS. 1 to 4, a flat engine frame 7 is connected to a rear frame 6 and extends rearward. An air-cooled single-cylinder engine 4 is mounted on the engine frame 7. Supported.

As shown in FIGS. 3 and 5 , the gear transmission 8 is connected to the front portion of the crankcase of the engine 4 . An input shaft 25 and an output shaft 26 are supported in the front-rear direction inside the gear transmission portion 8 . The input shaft 25 of the gear transmission portion 8 is connected to the output shaft 4a of the engine 4, and the transmission gear 25a of the input shaft 25 and the transmission gear 26a of the output shaft 26 are meshed.

As shown in FIGS. 3, 4 and 5, an input shaft 27 protrudes rearward from the upper portion of the rear portion of the transmission case 20, and the input shaft 27 is arranged at the left-right center A1 of the body 1 in plan view. The output shaft 26 is arranged concentrically with the input shaft 27 , and the transmission shaft 18 is connected across the output shaft 26 and the input shaft 27 .

With the above configuration, the power of the engine 4 is transmitted from the output shaft 4a of the engine 4 to the input shaft 25 of the gear transmission portion 8, reversed by the transmission gear 25a of the input shaft 25 and the transmission gear 26a of the output shaft 26, and output The power is transmitted to the input shaft 27 of the transmission case 20 via the shaft 26 and the transmission shaft 18 .

(Configuration of transmission system inside transmission case)
As shown in FIGS. 5 and 10, the transmission shaft 40 is supported in the upper part inside the transmission case 20 along the left-right direction, and the bevel gear 27a of the input shaft 27 and the bevel gear 40a of the transmission shaft 40 mesh. ing. The transmission shaft 41 is supported along the front-rear direction in the lower portion inside the transmission case 20, and the transmission gear 27b of the input shaft 27 and the transmission gear 41a of the transmission shaft 41 are engaged with each other.

The output shaft 28 (see FIGS. 3 and 8) is supported so as to protrude forward from the lower front portion of the transmission case 20, and is arranged concentrically with the transmission shaft 41. The transmission shaft 41 and the output shaft 28, a hydraulically operated working clutch 42 is provided.

(Configuration of continuously variable transmission housed in left and right transmission cases)
As shown in FIGS. 5 and 10 , left and right hydrostatic continuously variable transmissions 32 are housed in left and right transmission cases 21 . The continuously variable transmission 32 has an input shaft 33, an output shaft 34, a variable displacement axial plunger hydraulic pump 35, an axial plunger hydraulic motor 36, a port block 24, and the like.

The input shaft 33 supports the hydraulic pump 35 on its outer peripheral portion, and is rotatably supported on the front portion (upper portion) of the transmission case 21 by the bearing 43 and the port block 24 of the housing case 23 . Inside the transmission case 20, the input shaft 33 and the transmission shaft 40 are connected by a spline structure.

The output shaft 34 supports a hydraulic motor 36 on its outer periphery, and is rotatably supported at the rear (lower portion) of the transmission case 21 by the accommodation case 23 , port block 24 and axle case 22 .

As shown in FIG. 6, inside the port block 24, a pair of oil passages 37 connecting a hydraulic pump 35 and a hydraulic motor 36 are provided, and a charge oil passage 38 is connected across the oil passages 37. there is

As shown in the above (configuration of the transmission case, the transmission case, and the axle case) and FIG. The hydraulic pump 35 is arranged at a position higher than the hydraulic motor 36 in the continuously variable transmission 32 by being arranged at a position higher than the rear portion of the case 23 ).

As shown in FIGS. 7, 8, and 9, left and right brackets 39 are connected to the right and left rear portions of the transmission case 20, and left and right brackets 45 are connected to the top of the brackets 39. As shown in FIGS. Left and right brackets 46 are connected to the front end (upper end) of the port block 24 of the transmission case 21 .

As shown in FIGS. 1, 2, 3, 8 and 9, left and right operation mechanisms 31 having electric motors 31a are connected across brackets 45 and 46, and the right operation mechanism 31 is connected to the right transmission case 21. The left operation mechanism 31 is arranged above the left shift case 21 . The swash plate 35a (see FIG. 10) of the hydraulic pump 35 of the left and right continuously variable transmission 32 is operated by the electric motor 31a of the left and right operation mechanism 31, and the left and right continuously variable transmission 32 are separately moved forward and backward. The speed is changed steplessly.

(Configuration of transmission system inside axle case)
As shown in FIGS. 5 and 10, the output shaft 34 of the continuously variable transmission 32 is inserted inside the left and right axle cases 22, and left and right brakes 47 capable of braking the output shaft 34 are provided. .

The left and right axles 44 are supported by the axle case 22 and the port block 24 along the left-right direction. ) are in occlusion. Axle 44 protrudes laterally outward from the axle case 22 , and driving wheel 15 is connected to the protruding portion of axle 44 .

As described in the above (Configuration of the transmission system from the engine to the transmission case), the power transmitted to the input shaft 27 of the transmission case 20 is transmitted to the above-described (Configuration of the transmission system inside the transmission case). The power is transmitted to the left and right continuously variable transmissions 32 via the bevel gear 27 a of the input shaft 27 , the bevel gear 40 a of the transmission shaft 40 , the transmission shaft 40 and the input shaft 33 . The power of the output shaft 34 of the continuously variable transmission 32 is transmitted to the drive wheels 15 via the transmission gear 34a of the output shaft 34, the transmission gear 44a of the axle 44, and the axle 44, and the drive wheels 15 rotate the crawler belt 19. driven.

As described in (Construction of Continuously Variable Transmission Housed in Left and Right Transmission Cases), the left and right continuously variable transmissions 32 are separately operated forward and backward in a stepless manner by the operation mechanism 31. By doing so, the machine body 1 can move forward and backward, stop, turn to the right and left in forward and backward movement, pivot turn and super pivot turn.

(Configuration of Mower)
As shown in FIGS. 1 and 2, the mower 3 includes a casing 63 having a ceiling and left and right side portions, and a drum 65 supporting a large number of cutting blades 64 extending in the left and right direction. It is configured to be rotatably supported around an axis. A round pipe-shaped reinforcing frame 66 is connected across the right and left rear portions of the casing 63 and the bracket 63 a of the casing 63 , and left and right ground wheels 67 of the caster wheel type are attached to the front of the casing 63 . supported by the department.

As shown in FIGS. 1 to 4, an output case 68 is connected to the front frame 5, a bracket 69 is connected to the left frame 9, and a round pipe-shaped support frame 70 extends in the left-right direction. It is connected across the case 68 and the bracket 69 . A channel-shaped bracket 73 is connected to the right frame 9 .

A support arm 71 is supported by a bracket 73 and extended forward so as to be vertically swingable about an axis P1 extending in the left-right direction. A support arm 72 is supported by the support frame 70 so as to be vertically swingable about an axis P1, and extends forward.

The front part of the support arm 71 is connected to the reinforcing frame 66, the front part of the support arm 72 is connected to the left lateral side of the casing 63, and the mower 3 can be raised and lowered by the support arms 71 and 72. supported by A single-acting elevating cylinder 74 is connected across the front frame 5 and the reinforcing frame 66 , and the mower 3 is operated to elevate by the elevating cylinder 74 .

(Structure of transmission system to mowing device)
As shown in FIGS. 3 and 5, in the output case 68, a cylindrical input shaft 75 is supported in the rear portion of the output case 68 along the front-rear direction. The output shaft 28 of the transmission case 20 is inserted into the input shaft 75, and the input shaft 75 and the output shaft 28 are connected by a spline structure.

A transmission shaft 76 is supported inside the output case 68 along the left-right direction, and a bevel gear 75a of the input shaft 75 and a bevel gear 76a of the transmission shaft 76 are engaged. The transmission shaft 77 is supported coaxially with the axis P1 over the inside of the output case 68 and the support frame 70, and the transmission gear 76b of the transmission shaft 76 and the transmission gear 77a of the transmission shaft 77 are engaged. there is

As shown in FIGS. 2 and 5, a driving pulley 79 is attached to the left end of the transmission shaft 77, and a driven pulley 80 is attached to the driving shaft 78 of the drum 65 of the mowing device 3. A transmission belt 81 is attached over 80 .

As described above (the configuration of the transmission system inside the transmission case) and as shown in FIG. It is transmitted to the input shaft 75 of the output case 68 via the output shaft 28 .

In the output case 68, the power of the input shaft 75 is transferred to the bevel gear 75a of the input shaft 75, the bevel gear 76a of the transmission shaft 76, the transmission shaft 76, the transmission gear 76b of the transmission shaft 76, the transmission gear 77a of the transmission shaft 77, the transmission shaft 77, It is transmitted to the drive shaft 78 via the transmission belt 81 . In the grass cutting device 3, the drum 65 and the cutting blade 64 are rotated counterclockwise in FIG.

(Configuration for supplying lubricating oil stored in the transmission case to the continuously variable transmission as hydraulic oil)
As shown in FIG. 10 , lubricating oil is stored in the transmission case 20 . The position of the oil surface (oil level) of the lubricating oil in the transmission case 20 is substantially the same as the output shaft 34 of the continuously variable transmission 32 or at the same position as the continuously variable transmission 32 when the traveling device 2 is in contact with the horizontal surface. It is set at a position between the input shaft 33 and the output shaft 34 . A breather (not shown) is provided on the transmission case 20 .

As shown in FIGS. 6 and 9 , a charge pump 48 is provided at the input shaft 27 in the rear portion of the transmission case 20 , and the charge pump 48 is driven by the input shaft 27 . A strainer 49 is attached to the lower portion of the rear portion of the transmission case 20 and is positioned close to the bottom of the interior of the transmission case 20. An oil passage 50 connected across the charge pump 48 and the strainer 49 is provided. , are provided in the rear portion of the transmission case 20 along the vertical direction.

As shown in FIGS. 6 to 9, an elevation control valve 51 for supplying and discharging working oil to and from the elevation cylinder 74 of the mower 3 (see the above-described (Mower configuration)), and a working clutch 42 (the above-described (Transmission A work control valve 52 for supplying and discharging working oil is provided at the upper part of the rear part of the transmission case 20 .

A filter 29 is provided in the upper front portion of the transmission case 20 , and a metal pipe member 53 is arranged above the upper portion of the transmission case 20 and connected across the charge pump 48 and the filter 29 . there is

Left and right pipe members 54 in the shape of metal pipes extend from the filter 29 toward the left and right laterally outward sides. The right pipe member 54 is connected to the front end (upper end) of the port block 24 of the right transmission case 21 and connected to the charge oil passage 38 of the right continuously variable transmission 32 . The left pipe member 54 is connected to the front end (upper end) of the port block 24 of the left transmission case 21 and connected to the charge oil passage 38 of the left continuously variable transmission 32 .

By driving the charge pump 48 , the lubricating oil stored in the transmission case 20 is supplied to the charge pump 48 via the strainer 49 and the oil passage 50 as hydraulic oil. Hydraulic oil (lubricating oil) from the charge pump 48 is supplied to the filter 29 via the pipe member 53 , passes through the filter 29 and is supplied to the charge oil passage 38 via the pipe member 54 , and is supplied to the continuously variable transmission 32 . supplied to

At the same time, hydraulic oil (lubricating oil) from the charge pump 48 is supplied to the elevation control valve 51 and the work control valve 52 . When the elevation control valve 51 is operated, the elevation cylinder 74 is expanded and contracted to raise and lower the grass cutting device 3 . By operating the work control valve 52, the work clutch 42 is operated into a transmission state and a cut-off state.

(Structure of the groove for removing the air inside the transmission case)
Hydraulic oil (lubricating oil) is supplied to the continuously variable transmission 32 by the charge pump 48, as described above (the configuration in which the lubricating oil stored in the transmission case is supplied to the continuously variable transmission as working oil) and as shown in FIG. In this case, lubricating oil leaks from the hydraulic pump 35 and the hydraulic motor 36 into the shift case 21 .

As shown in FIGS. 10, 11, and 12, a mounting surface portion 23a is formed at the end portion of the housing case 23. As shown in FIGS. In the bearing 43 capable of supporting the portion of the input shaft 33 on the side of the transmission shaft 40 (see the above-mentioned (configuration of the continuously variable transmission housed in the left and right transmission cases)), the outer race 43a of the bearing 43 is located in the housing case. 23 is attached to the mounting surface portion 23a. A stopper ring 55 is attached to the mounting surface portion 23 a of the housing case 23 , and the outer race 43 a of the bearing 43 is stopped by the stopper ring 55 .

A portion behind the input shaft 33 at the same height as the input shaft 33 in the mounting surface portion 23a of the housing case 23 is milled. As a result, between the mounting surface portion 23a of the housing case 23 and the outer race 43a of the bearing 43, a groove portion 56 (corresponding to a throttle passage) along the radial direction (front-rear direction) of the input shaft 33 and the bearing 43 and the input shaft A groove portion 57 (corresponding to a throttle passage) is formed along the longitudinal direction (horizontal direction) of 33 . The grooves 56 and 57 are provided across the transmission case 20 and the left and right shift cases 21 so that the inside of the transmission case 20 and the inside of the shift case 21 communicate with each other.

A stopper ring 55 enters the groove portion 57 to narrow the opening area of the groove portion 57 . The groove portion 57 is formed deeper than the groove portion to which the stopper ring 55 is attached so that the outer peripheral portion of the stopper ring 55 does not reach the bottom portion of the groove portion 57 . As a result, a narrow gap is formed between the bottom portion of the groove portion 57 and the outer peripheral portion of the stopper ring 55 , and the cross-sectional area of the groove portion 57 is partially reduced by the stopper ring 55 .

As described in (Configuration of continuously variable transmission housed in left and right transmission cases), the hydraulic pump 35 is arranged at a position higher than the hydraulic motor 36 in the continuously variable transmission 32, so that the input shaft The grooves 56 and 57, which are arranged at the same height as 33, are arranged at a position higher than the hydraulic motor 36, and the oil level of the lubricating oil in the transmission case 20 (the oil level stored in the transmission case as described above). ), which supplies lubricating oil as hydraulic oil to the continuously variable transmission).

As shown in FIGS. 6, 11, and 12, the air inside transmission case 21 passes through grooves 56 and 57 and flows into transmission case 20. As shown in FIGS. Even if the lubricating oil inside the transmission case 21 passes through the grooves 56 and 57 and tries to flow into the transmission case 20, the resistance due to the labyrinth arrangement where the grooves 56 and 57 are perpendicular to each other and the stopper ring 55 Passage of lubricating oil is resisted by a throttling action that partially reduces the cross-sectional area of the groove 57 by entering the groove 57 .

(Structure related to the flow of lubricating oil in the transmission case, speed change case and axle case)
As shown in FIGS. 6 and 10 , in the port blocks 24 of the left and right shift cases 21 , the hydraulic pump 35 and the hydraulic motor 36 are located between the hydraulic pump 35 and the hydraulic motor 36 , and extend through the inside of the shift cases 21 and the axle cases 22 . A through-hole 60 (corresponding to a first passage) is opened for communication.

A through hole 61 (corresponding to a first passage) is formed in the port block 24 of the left and right shift cases 21 in the lower rear portion of the hydraulic motor 36 so that the inside of the shift case 21 and the inside of the axle case 22 communicate with each other. ) is open.
This allows the lubricating oil to pass through the through holes 60 and 61 throughout the transmission case 21 and the axle case 22 .

As shown in FIGS. 6 to 9, left and right pipe members 62 (corresponding to second passages and pipe members) made of metal or rubber are provided. The connecting portion 58 (corresponding to the connecting portion of the tube member to the axle case) is connected to the upper portion of the left and right axle cases 22 , and the pipe member 62 communicates with the inside of the axle case 22 .

A connection portion 59 (corresponding to a connection portion of the pipe member to the transmission case) is connected to the lower left portion of the transmission case 20, and the other ends of the left and right pipe members 62 are connected to the connection portion 59. , the pipe member 62 communicates with the inside of the transmission case 20 .

Thereby, the pipe member 62 is provided across the transmission case 20 and the axle case 22, and the lubricating oil can pass through the pipe member 62 across the inside of the transmission case 20 and the inside of the axle case 22. be.

The connecting portion 59 is arranged at a position lower than the connecting portion 58 when the travel device 2 is in contact with the horizontal surface. The connection portion 59 is located above the position of the oil surface (oil level) of the lubricating oil in the transmission case 20 (see the above-mentioned (configuration for supplying the lubricating oil stored in the transmission case as the hydraulic oil to the continuously variable transmission)). placed in a low position.

With the above configuration, as shown in FIGS. 6 to 9, hydraulic oil (lubricating oil) is supplied from the charge pump 48 to the continuously variable transmission 32, and is supplied from the hydraulic pump 35 and the hydraulic motor 36 to the inside of the transmission case 21. When the lubricating oil leaks, the lubricating oil in the transmission case 21 enters the inside of the axle case 22 through the through holes 60 and 61, and the lubricating oil in the axle case 22 returns to the transmission case 20 through the pipe member 62. , the occurrence of lubricating oil flow can be expected.

(First alternative embodiment of the invention)
The grooves 56 and 57 may be provided in the front portion of the input shaft 33 in the attachment surface portion 23 a of the housing case 23 , or may be provided in both the front and rear portions of the input shaft 33 .

(Second alternative embodiment of the invention)
A plurality of grooves 56 and 57 may be provided in the front or rear portion of the input shaft 33 at a position higher than the axial center of the input shaft 33 in the mounting surface portion 23 a of the housing case 23 . may be provided more than once.

(Third alternative embodiment of the invention)
Instead of providing the groove portions 56 and 57 in the mounting surface portion 23a of the storage case 23, a throttle passage in the form of a tubular member made of metal or rubber is formed in the transmission case 20 over the upper portion of the transmission case 20 and the upper portion of the transmission case 21. 20 and the outside of the transmission case 21 may be connected.

(Fourth alternative embodiment of the invention)
Instead of the engine 4, an electric motor (not shown) may be provided as a prime mover.

Instead of the crawler-type traveling device 2 , wheels (not shown) for traveling may be provided as the traveling device 2 . In this configuration, instead of equipping the left and right continuously variable transmissions 32, a single continuously variable transmission 32 may be installed and the power of the continuously variable transmission 32 may be transmitted to the left and right wheels. .

The present invention can also be applied to a work vehicle equipped with other work devices such as a snow removal device (not shown) or a rotary tillage device (not shown) in place of the mowing device 3. It can be applied not only to cars but also to work vehicles driven by workers.

2 traveling device 4 engine (motor unit)
20 Transmission case 21 Transmission case 22 Axle case 23a Mounting surface 24 Port block (wall)
32 continuously variable transmission 33 input shaft 34a transmission gear (transmission system)
35 Hydraulic Pump 36 Hydraulic Motor 40 Transmission Shaft 43 Bearing 43a Outer Race 44 Axle 44a Transmission Gear (Transmission System)
48 charge pump 55 stopper ring 56 groove (throttle passage)
57 Groove (throttle passage)
58 connection part (connection part)
59 connection part (connection part)
60 through hole (first passage)
61 through hole (first passage)
62 pipe member (second passage, pipe member)

Claims (10)

a transmission case accommodating a transmission shaft to which power of the driving portion is transmitted;
a hydrostatic continuously variable transmission having a hydraulic pump to which the power of the transmission shaft is transmitted and a hydraulic motor to output the power;
a transmission case that is connected to the transmission case and houses the continuously variable transmission;
a traveling device driven by transmission of the power of the hydraulic motor,
a charge pump capable of supplying lubricating oil stored in the transmission case to the continuously variable transmission as hydraulic oil;
A throttle passage is provided across the transmission case and the speed change case and allows passage of air through the interior of the transmission case and the interior of the speed change case and provides resistance to the passage of lubricating oil. work vehicle. The hydraulic pump is arranged at a position higher than the hydraulic motor,
The working vehicle according to claim 1, wherein the throttle passage is arranged at a position higher than the hydraulic motor. an input shaft that supports the hydraulic pump, is rotatably supported by the transmission case, and is connected to the transmission shaft;
a bearing capable of supporting a portion of the input shaft on the side of the transmission shaft and attached to the transmission case,
3. The throttle passage according to claim 1 or 2, wherein the throttle passage is a groove provided in a mounting surface portion of the transmission case to which the outer race of the bearing is mounted, extending between the interior of the transmission case and the interior of the transmission case. work vehicle. A stopper ring for stopping the outer race is attached to the transmission case,
4. The work vehicle according to claim 3, wherein the stopper ring enters into the groove to reduce the opening area of the groove. an axle case that is connected to the transmission case, has an axle that drives the travel device, and houses a transmission system that transmits the power of the hydraulic motor to the axle;
a first passage that is provided across the transmission case and the axle case and allows lubricating oil to pass through the interior of the transmission case and the interior of the axle case;
5. The method according to any one of claims 1 to 4, further comprising a second passage extending between the transmission case and the axle case and through which lubricating oil can pass through the interior of the transmission case and the interior of the axle case. The work vehicle according to any one of the items. 6. The work vehicle according to claim 5, wherein the first passage is a through hole formed in a wall partitioning the transmission case and the axle case and extending through the inside of the transmission case and the inside of the axle case. . 7. The work vehicle according to claim 6, wherein the through hole is opened in a portion of the wall portion between the hydraulic pump and the hydraulic motor. the second passage is a tubular member connected across the transmission case and the axle case,
The work vehicle according to any one of claims 5 to 7, wherein a connection portion of the pipe member with the transmission case is arranged at a position lower than a connection portion of the pipe member with the axle case. . 9. The work vehicle according to claim 8, wherein a connection portion of the pipe member to the transmission case is arranged at a position lower than the oil level of lubricating oil stored in the transmission case. a transmission case accommodating a transmission shaft to which power of the driving portion is transmitted;
a hydrostatic continuously variable transmission having a hydraulic pump to which the power of the transmission shaft is transmitted and a hydraulic motor to output the power;
a transmission case that is connected to the transmission case and houses the continuously variable transmission;
a running device;
an axle case that is connected to the transmission case, has an axle that drives the travel device, and houses a transmission system that transmits the power of the hydraulic motor to the axle;
a charge pump capable of supplying lubricating oil stored in the transmission case to the continuously variable transmission as hydraulic oil;
a throttle passage that is provided across the transmission case and the speed change case, allows air to pass through the interior of the transmission case and the speed change case, and provides resistance to the passage of lubricating oil;
a first passage that is provided across the transmission case and the axle case and allows lubricating oil to pass through the interior of the transmission case and the interior of the axle case;
A work vehicle comprising a second passage extending between the transmission case and the axle case, and through which lubricating oil can pass through the interior of the transmission case and the interior of the axle case.

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