JP2008138823A - Transmission unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simply structured transmission unit which can effectively keep a lubricity of gear transmission mechanism while effectively preventing a transmission efficiency of the transmission mechanism from decreasing, and preventing temperature rise of oil stored in a gear casing in a transmission unit in which the gear transmission mechanism is housed inside the gear casing which can store oil. <P>SOLUTION: When each transmission gear 231, 232, 233 of a gear transmission mechanism 230 rotates with accompanying rotation of an input shaft 210 by power of a drive source 2, oil Q stored in the gear housing part 240a is mixed with accompanying that. On the other hand, the gear housing part 240a and the oil storage part 245a are partitioned by a rib 244 provided in the gear casing 240. Consequently, mixing action of the oil Q in the oil storage part 245a partitioned by the rib 244 is weakened as compared with mixing action of the oil Q in the gear housing part 240a (less influence of mixing) when the oil Q stored in the gear housing part 240a is mixed by the gear transmission mechanism 230. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission unit applied to a work vehicle or the like.

It is known to insert a gear transmission mechanism (for example, a gear train) accommodated in a gear case into a transmission path in a work vehicle.
For example, such a configuration is adopted in order to output the output of the flywheel body from a position displaced from the axial center position of the flywheel body (see Patent Document 1 below).

Incidentally, the lubrication of the gear transmission mechanism accommodated in the gear case is generally performed by the stored oil in the gear case.
However, if the oil level of the stored oil in which the gear transmission mechanism is immersed is increased, the amount of stored oil in the gear case increases, and the gear transmission mechanism can be sufficiently lubricated, but the stored oil is agitated for the gear transmission mechanism. It becomes resistance, and the transmission efficiency of the gear transmission mechanism deteriorates.
On the other hand, if the oil level of the stored oil immersed in the gear transmission mechanism is lowered to reduce the amount of stored oil in the gear case, deterioration of the transmission efficiency of the gear transmission mechanism due to the stored oil can be prevented, but the oil temperature of the stored oil As a result, the gear transmission mechanism deteriorates in lubricity.
JP 2005-106231 A

  The present invention has been made in view of the prior art, and in a transmission unit in which a gear transmission mechanism is housed in a gear case capable of storing oil, while effectively preventing deterioration in transmission efficiency of the gear transmission mechanism, An object of the present invention is to provide a transmission unit having a simple structure capable of preventing the temperature rise of stored oil in the gear case and effectively maintaining the lubrication of the gear transmission mechanism.

  A transmission unit according to the present invention is supported by the first end surface in a state where an oil storage gear case having first and second end surfaces facing each other and an end portion on the upstream side in the transmission direction can be operatively connected to a drive source. An input shaft whose end on the downstream side in the transmission direction is supported on the second end surface, an end on the upstream side in the transmission direction is supported on the first end surface, and an end on the downstream side in the transmission direction outputs rotational power. A transmission unit comprising an output shaft supported on the second end face in a state of being obtained and a gear transmission mechanism for transmitting power from the input shaft to the output shaft, wherein the gear case has an internal space in the gear transmission. A rib for partitioning into a gear housing portion that houses the mechanism and an oil storage portion that is allowed to circulate oil with respect to the gear housing portion is provided.

According to the transmission unit configured as described above, the input shaft and the output shaft are supported on the first and second end faces of the gear case capable of storing oil. The first end face side of the input shaft is the upstream side in the transmission direction, and the drive source is operatively connected to the upstream end of the input shaft in the transmission direction. The power from the drive source is transmitted from the input shaft to the output shaft via the gear transmission mechanism. In the output shaft, the second end surface side is the downstream side in the transmission direction, and the rotational power transmitted to the output shaft is output from the second end surface side.
Here, the internal space of the gear case is partitioned into a gear housing portion and an oil storage portion by ribs provided in the gear case. For this reason, when the stored oil in the gear housing portion is agitated by the gear transmission mechanism housed in the gear housing portion, the agitating action of the stored oil in the oil reservoir portion partitioned by the rib is agitated by the stored oil in the gear housing portion. It becomes weaker than that (it is less susceptible to stirring).

  Therefore, the temperature rise of the stored oil in the oil storage unit can be more effectively suppressed. Thereby, without increasing the stirring resistance in the gear transmission mechanism (without deteriorating the transmission efficiency), it is possible to suppress the temperature rise of the stored oil in the gear housing portion and to effectively maintain the lubrication of the gear transmission mechanism. it can.

  Preferably, the rib is provided so as to overlap with at least a lowermost gear among the gears constituting the gear transmission mechanism in a side view.

In this case, with respect to the length (height) of the rib in the rotational axis direction of the gear, at least one end and the other end of the rotational axis direction of the gear located at the lowest position among the gears constituting the gear transmission mechanism are exceeded. Ribs are provided. Thus, when the oil stored in the gear housing portion is agitated by the gear transmission mechanism, even if the oil urged in the radial direction of the gear by the rotation of the gear scatters toward the oil storage portion, the oil is retained in the ribs. As a result, the hot oil is prevented from entering the oil reservoir directly.
Therefore, by more effectively suppressing the stirring action of the oil stored in the oil storage part, the temperature increase of the oil stored in the oil storage part can be prevented, and the temperature increase of the stored oil in the entire gear case Can be suppressed more effectively.

  Preferably, on the basis of the state in which the gear case is mounted on the attachment site, an oil circulation portion that communicates the gear housing portion and the oil storage portion is provided on the upper end side and the lower end side of the rib. Composed.

In this case, the gear housing portion and the oil storage portion are communicated with each other through an oil circulation portion provided on the upper end side and the lower end side of the rib with reference to a state where the gear case is attached.
As a result, the oil in the gear housing portion that has been lifted up by the gear transmission mechanism and has risen in temperature enters the oil storage portion side from the oil circulation portion on the upper end side of the rib, while oil having a lower temperature than the oil stored in the gear housing portion is ribbed. Enters the gear housing part side from the oil circulation part on the lower end side. Thereby, the temperature rise of the stored oil in the gear housing portion can be effectively prevented while efficiently circulating the oil whose temperature has increased and the low temperature oil to cool the oil that has entered the oil storage portion.

  Preferably, the second end surface of the gear case is configured such that a region corresponding to the oil reservoir is bulged downstream in the transmission direction of the output shaft.

  In this case, the amount of stored hot water can be increased without raising the oil level of the stored oil in which the gear transmission mechanism is immersed in the gear housing portion by the amount that the oil storage portion bulges from the second end surface of the gear case. Thereby, without increasing the stirring resistance in the gear transmission mechanism (without deteriorating the transmission efficiency), it is possible to suppress the temperature rise of the stored oil in the gear housing portion and to effectively maintain the lubrication of the gear transmission mechanism. it can.

  According to the transmission unit according to the present invention, it is possible to more effectively suppress the temperature rise of the stored oil in the oil storage section. Thereby, without increasing the stirring resistance in the gear transmission mechanism (without deteriorating the transmission efficiency), it is possible to suppress the temperature rise of the stored oil in the gear housing portion and to effectively maintain the lubrication of the gear transmission mechanism. it can.

Hereinafter, a preferred embodiment of a transmission unit according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic side view of a working vehicle 100 (here, a riding tractor) to which an example 200 of a transmission unit according to the present invention is applied, and FIG. 2 is a schematic transmission diagram in the working vehicle 100 of FIG.

As shown in FIGS. 1 and 2, the working vehicle 100 includes a body frame 1, a drive source 2 supported by the body frame 1, a transmission 3 that shifts rotational power from the drive source 2, The main drive wheel 5 driven by the rotational power shifted by the transmission 3 and the transmission unit 200 inserted in the transmission path from the drive source 2 to the transmission 3 are provided.
In the present embodiment, the working vehicle 100 has a steering wheel 4 and a non-steering wheel 5 on one side and the other side in the vehicle front-rear direction, respectively, and the non-steering wheel 5 serves as the main driving wheel. It is working.
In the present embodiment, the working vehicle 100 is adapted to transmit the rotational power changed by the transmission 3 to the steered wheels 4, and the steered wheels 4 are sub-drive wheels. It comes to act as.
In the present embodiment, an engine is used as the drive source 2, but an electric motor may be used.

  In the working vehicle 100, the drive source 2 is disposed inside the hood 6 at the front of the traveling machine body. A driving unit case 9 is disposed behind the bonnet 6, and an operating system (not shown) such as a steering column and a shift lever is provided in the driving unit case 9. A driver's seat (not shown) is disposed in the driver's case 9 and above the mission case 3.

  A step base 12 is provided below the front side of the driver seat, and the rear wheel fender 11 is provided behind the step base 12.

In this embodiment, the drive source 2 and the transmission 3 are spaced apart in the vehicle front-rear direction, and the transmission unit 200 is provided on the drive source 2 side as shown in FIGS. 1 and 2. Yes.
The transmission unit 200 is provided to output rotational power to the subsequent transmission 3 at a position displaced from the output shaft 2 a of the drive source 2. The detailed configuration of the transmission unit 200 will be described later.

In the present embodiment, the transmission unit 200 is configured to input rotational power from the drive source 2 via the flywheel 7.
FIG. 3 shows a vertical side view of the vicinity of the transmission unit 200 in the work vehicle 100. In FIG. 3, a plane including axes of an input shaft 210 and an output shaft 220 described later is taken as a cross section.
As shown in FIGS. 2 and 3, the flywheel 7 includes a flywheel body 7a operatively connected to the output shaft 2a, an output portion 7c connected to the flywheel body 7a via a damper 7b, A flywheel housing 13 surrounding the flywheel body 7a and the output portion 7c;
In the present embodiment, the flywheel housing 13 is connected to the drive source 2 on the upstream side in the transmission direction, and supports the transmission unit 200 on the downstream side in the transmission direction.

The transmission 3 is configured to input rotational power from the drive source 2 via the transmission unit 200.
In the present embodiment, the transmission 3 receives rotational power from the transmission unit 200 via a transmission shaft 17 with a universal joint, as shown in FIG.

  As shown in FIG. 2, the transmission 3 includes a traveling system transmission mechanism 310, a PTO system transmission mechanism 320, and a transmission case 30 that supports or accommodates the traveling system transmission mechanism 310 and the PTO system transmission mechanism 320. ing.

  In the present embodiment, the traveling transmission mechanism 310 includes a hydrostatic continuously variable transmission (HST) 311 that functions as a main transmission, and a mechanical transmission 312 that functions as an auxiliary transmission.

  The HST 311 is fluidly connected to a pump shaft 311a for inputting rotational power from the drive source 2 through the transmission unit 200, a hydraulic pump body 311b that is rotationally driven by the pump shaft 311a, and the hydraulic pump body 311b. A hydraulic motor main body 311c, a motor shaft 311d rotated by the hydraulic motor main body 311c, an HST housing 19 that houses the hydraulic pump main body 311b and the hydraulic motor main body 311c, and the hydraulic pump main body 311b. At least one of the hydraulic motor main body 311c is a variable displacement type. In the present embodiment, as shown in FIG. 2, the hydraulic pump body 311b is of a variable displacement type.

The HST housing 19 is supported on the end face of the transmission case 30 on the upstream side in the transmission direction.
The pump shaft 311a has an end on the upstream side in the transmission direction forming an input end extending outward from the HST housing 19 and an end on the downstream side in the transmission direction extending into the transmission case 30. Thus, it is supported by the HST housing 19.
The motor shaft 311d is supported by the HST housing 19 so that an end on the downstream side in the transmission direction that forms an output end protrudes into the transmission case 30.

In the present embodiment, the traveling transmission mechanism 310 includes a planetary gear device 313 in addition to the HST 311 and the mechanical transmission device 312 in order to increase the speed change width.
The planetary gear device 313 forms an HMT in cooperation with the HST 311.
Specifically, the planetary gear device 313 functions as a first element for inputting constant speed power via the pump shaft 311a, a second element for inputting speed change power via the motor shaft 311d, and an output member. And a third element.
In the present embodiment, as shown in FIG. 2, the ring gear 313a constitutes the first element, the sun gear 313b constitutes the second element, and the carrier 313c constitutes the third element. .

As shown in FIG. 2, the mechanical transmission 312 has a drive shaft 312a, a driven shaft 312b, and a plurality of gear trains 312c, and any one of the plurality of gear trains 312c. Is selected, the rotational speed of the driven shaft 312b can be shifted in multiple stages with respect to the drive shaft 312a.
In this embodiment, the mechanical transmission 312 includes the drive shaft 312a, the driven shaft 312b, the forward high speed gear train 312c1 and the forward low gear gear train 312c2 that are inserted in the forward transmission path. A reverse gear train 312c3 inserted in the reverse transmission path, a forward output state in which the output of the HMT is transmitted to the forward transmission path, a reverse output state in which the output of the HMT is transmitted to the reverse transmission path, Alternatively, the hydraulic clutch unit 312d that can selectively take a neutral state in which the output of the HMT is cut off from both transmission paths and the forward high speed gear train 312c1 or the forward low gear gear train 312c2 are selectively engaged. And a shifter (not shown) to be combined.

  As shown in FIG. 2, the traveling system transmission mechanism 310 further includes a differential gear device 314 for main drive wheels that differentially transmits the rotational power from the mechanical transmission device 312 to the pair of main drive shafts 5a. Have.

Furthermore, in the present embodiment, as shown in FIG. 2, the traveling system transmission mechanism 310 includes a sub drive wheel power take-out device 315 in addition to the above-described configuration.
The secondary drive wheel power take-out device 315 can output rotational power synchronized with rotational power output toward the main drive wheel 5 toward the secondary drive wheel 4 via the secondary drive shaft 4a. It is configured.

In the present embodiment, the auxiliary drive wheel power take-out device 315 includes a four-wheel drive state in which the auxiliary drive wheel 4 is driven in synchronization with the main drive wheel 5, and the auxiliary drive wheel 4 is moved to the main drive wheel. It is configured to be able to take a speed increasing state in which the driving speed is higher than 5, and a neutral state in which the output to the auxiliary driving wheel 4 is interrupted.
Specifically, the auxiliary drive wheel power take-out device 315 includes a drive shaft 315a, a driven shaft 315b, a 4-drive gear train 315c1 disposed between the auxiliary drive wheel 4 and the driven shaft 315b, and A speed increasing gear train 315c2, a four-drive state in which the drive shaft 315a is operatively connected to the driven shaft 315b via the four-drive gear train 315c1, and the drive wheel via the speed increasing gear train 315c2. A hydraulic clutch unit 315d that can be in a speed-up state in which it is operatively connected to the driven shaft 315b or a neutral state in which power transmission from the drive shaft 315a to the driven shaft 315b is interrupted.

The PTO transmission mechanism 320 is configured to output the rotational power from the drive source 2 toward an attached work machine.
In the present embodiment, the PTO transmission mechanism 320 includes a PTO shaft 18 supported by the transmission case 30 so that rotational power can be output toward the work machine, and an input shaft (the main shaft of the transmission 3). The embodiment includes a PTO hydraulic clutch unit 321 and a PTO transmission 322 that are inserted in a PTO transmission path from the pump shaft 311 a) to the PTO shaft 18.

The PTO hydraulic clutch unit 321 has a driving side operatively connected to the pump shaft 311a and a driven side operatively connected to the PTO transmission 322.
In the present embodiment, as shown in FIG. 2, the PTO transmission mechanism 320 further includes a PTO hydraulic brake unit 323 that operates contrary to the PTO hydraulic clutch unit 321.
That is, in the PTO hydraulic brake unit 323, when the PTO hydraulic clutch unit 321 is in a power transmission state, the PTO hydraulic brake unit 323 is in an inoperative state, and the PTO hydraulic brake unit 321 is in a power cutoff state. In this case, a braking force is applied to the driven side of the PTO hydraulic clutch unit 321.

Next, the transmission unit 200 will be described.
4 is an end view taken along the line IV-IV in FIG.

Here, the transmission unit 200 is provided at the rear portion of the flywheel housing 13 in order to transmit the power from the drive source 2 to the transmission 3 spaced apart from the drive source 2.
Here, since the driver's seat 10 is disposed above the transmission case 30, when the position of the driver's seat 10 is to be lowered, the transmission unit 200 outputs the output of the flywheel body 2b, With respect to the vertical direction of the transmission unit 200, the shaft center position of the output portion 7c of the flywheel 7 is required to be output from a displaced position.

That is, the transmission unit 200 includes the gear case 240 having a first end surface 241 and a second end surface 242 that are opposed to each other, and an end portion on the upstream side in the transmission direction, which can be operatively connected to the drive source 2. An input shaft 210 that is supported by the first end surface 241 and whose end on the downstream side in the transmission direction is supported by the second end surface 242; and an end on the upstream side in the transmission direction is supported by the first end surface 241 and downstream in the transmission direction An output shaft 220 supported by the second end surface 242 in a state where the end of the shaft can output rotational power, and a gear transmission mechanism 230 that transmits power from the input shaft 210 to the output shaft 220 (herein, as will be described later) A plurality of (three) transmission gears 231, 232 and 233.
A part of the flywheel housing 13 is integrally formed with a part of a gear case 240 including a first end 241 to be described later, and the gear case 240 is coupled with a subsequent member at the end surface IV-IV in FIG. However, the gear case 240 may be formed separately from the flywheel housing 13.

A gear transmission mechanism 230 is housed in a gear housing portion 240 a capable of storing oil in the gear case 240. The gear housing portion 240a includes first and second end surfaces 241 and 242 and a peripheral wall 243 extending between the first and second end surfaces 241 and 242 so as to face the peripheral portions of the plurality of transmission gears 231, 232, and 233. Thus, the gear case 240 is configured to be able to store oil. As described above, the input shaft 210 and the output shaft 220 are eccentrically arranged, so that the output shaft 2a of the drive source 2 and the input shaft (pump shaft 311a) of the transmission 3 are arranged at appropriate positions to transmit power. Can be realized.
The output shaft 220 is disposed substantially parallel to the input shaft 210 at a position displaced downward with respect to the axial center position of the input shaft 210.
In the present embodiment, the gear transmission mechanism 230 is employed only for the purpose of transmitting the power from the drive source 2 from the input shaft 210 to the output shaft 220 eccentric with respect to the input shaft 210. The gear ratio may be such that the side is decelerated or increased with respect to the input side.

  The output shaft 220 of the transmission unit 200 and the pump shaft 311a that is the input shaft of the transmission 3 are preferably on substantially the same straight line during normal operation. On the other hand, depending on the structure and / or arrangement of the drive source 2 and the transmission 3, the input shaft (pump shaft 311a) of the transmission 3 is relatively displaced in the vehicle width direction with respect to the input shaft 210 of the transmission unit 200. May be placed.

  For this reason, in the present embodiment, the pump shaft 311a of the transmission 3 is displaced to one side in the vehicle width direction (here, the right side) with reference to the state where the transmission case 30 is mounted on the body frame 1. Correspondingly, the output shaft 220 is positioned below the input shaft 210 in the vehicle width direction below the input shaft 210 with reference to a state in which the gear case 240 is mounted on the mounting portion (here, the flywheel housing 13). It is displaced to one side (here, the right side).

Here, FIG. 5 is a schematic cross-sectional view centering on the transmission unit 200 portion in the working vehicle 100, and is a schematic cross-sectional view in which a plane displaced from the cross section of FIG. 3 to the other side in the vehicle width direction is a cross section. is there. FIG. 6 is a schematic rear perspective view centering on the transmission unit 200 portion in the working vehicle 100, and FIG. 7 is a schematic front perspective view centering on the transmission unit 200 portion in the working vehicle 100. In FIG. 6, a pump case 244 of an auxiliary pump unit 280 described later is not shown, and in FIG. 7, the flywheel housing 13 is not shown.
In the transmission unit 200 of the present embodiment, the second end surface 242 of the gear case 240 has the output at a portion avoiding a region corresponding to the gear transmission mechanism 230, as shown in FIGS. A bulging portion 245 bulging to the downstream side in the transmission direction of the shaft 220 is provided, and the bulging portion 245 circulates oil with respect to the gear housing portion 240a in the gear case 240 housing the gear transmission mechanism 230. The oil storage part 245a made possible is formed.
The bulging portion 245 is located below the input shaft 210 on the other side (here, the left side) of the output shaft 220 in the vehicle width direction.

According to the transmission unit 200 configured as described above, the input shaft 210 and the output shaft 220 are supported by the first end surface 241 and the second end surface 242 of the gear case 240 that can store oil. The first end surface 241 side of the input shaft 210 is the upstream side in the transmission direction, and the drive source 2 is operatively connected to the end of the input shaft 210 on the upstream side in the transmission direction. The power from the drive source 2 is transmitted from the input shaft 210 to the output shaft 220 through the gear transmission mechanism 230. In the gear housing 240a in the gear case 240, oil Q is stored (oil level L), and at least one of the transmission gears 231, 232, 233 constituting the gear transmission mechanism 230 is immersed in the stored oil Q. The gear transmission mechanism 230 is accommodated in the gear accommodating portion 240a. In the output shaft 220, the second end surface 242 side is the downstream side in the transmission direction, and the rotational power transmitted to the output shaft 220 is output from the second end surface 242 side.
Further, the output shaft 220 is provided on a portion of the second end surface 242 of the gear case 240 that avoids the region corresponding to the gear transmission mechanism, here, below the transmission gear 232 and on the other side (left side) of the transmission gear 233 in the vehicle width direction. A bulging portion 245 that bulges downstream in the transmission direction is provided. An oil storage portion 245a is formed in the bulging portion 245, and a gear housing portion 240a in a gear case 240 that houses the gear transmission mechanism 230. Oil distribution is possible. Note that the position of the bulging portion 245 is not limited to this, and can be appropriately formed in an empty region on the second end face 242 side.

  Thus, by providing the bulging part 240 in which the oil storage part 245a is formed avoiding the region corresponding to the gear transmission mechanism 230, the oil level of the stored oil Q in which the gear transmission mechanism 230 is immersed in the gear housing part 240a. The amount of stored oil can be increased without increasing L.

  Note that a communication hole communicating with the oil reservoir 245a is provided on the distal end side of the bulging portion 240, and a drain bolt 247 is locked to the communication hole. By connecting a hose pipe or the like instead of the drain bolt 247, oil can be distributed to other oil passages such as the transmission 3. This makes it possible to increase the amount of stored oil without increasing the oil level (or lowering the oil level). It is also possible to adjust the hot water temperature in the oil reservoir 245a by performing oil temperature control using a temperature sensor or the like in another oil reservoir or the like that is allowed to circulate oil via a hose pipe or the like. It is.

  Further, since the output shaft 220 is disposed below the input shaft 210 in a state where the gear case 240 is mounted on the flywheel housing 13 that is an attachment site, the floor when the output shaft 220 is arranged below the floor of the work vehicle. Can be lowered and flattened. In addition, since the output shaft 220 is displaced to one side in the vehicle width direction from the input shaft 210, the pump shaft 311a of the transmission 3 disposed on the downstream side in the transmission direction connected to the output shaft 220 is in the vehicle width direction. When displaced to one side, the output shaft 220 (and the transmission shaft connected thereto) can be arranged so as to be substantially straight with respect to the pump shaft 311a of the transmission 3 on the downstream side in the transmission direction.

  Here, as shown in FIGS. 4 and 7, the gear case 240 in the present embodiment is provided with ribs 244 that partition the gear housing portion 240 a and the oil storage portion 245 a. In the present embodiment, the rib 244 extends from the second end surface 242 side to the first end surface 241 side (flywheel housing 13 side), and is attached to the flywheel housing 13 as an attachment member. Are separated from each other (that is, the height of the rib 244 (the length parallel to the axial direction of the output shaft 220) is shorter than the length between the first end surface 241 and the second end surface 242). It is configured so that oil can be distributed.

When the transmission gears 231, 232, and 233 of the gear transmission mechanism 230 rotate along with the rotation of the input shaft 210 by the power of the drive source 2, the oil Q stored in the gear housing portion 240 a is agitated accordingly. On the other hand, the gear housing portion 240 a and the oil storage portion 245 a are partitioned by ribs 244 provided on the gear case 240. For this reason, when the stored oil Q in the gear housing portion 240a is stirred by the gear transmission mechanism 230, the stirring action of the stored oil Q in the oil storing portion 245a partitioned by the ribs 244 is the stored oil Q in the gear housing portion 240a. It becomes weaker than the stirring effect of (is less susceptible to stirring).
Therefore, the temperature rise of the stored oil Q in the oil storage unit 245a can be more effectively suppressed. Thereby, without increasing the stirring resistance in the gear transmission mechanism 230 (without deteriorating the transmission efficiency), the temperature increase of the stored oil Q in the gear housing portion 240a is suppressed, and the gear transmission mechanism 230 is effectively lubricated. Can be maintained.

  In the present embodiment, as shown in FIG. 7, the rib 244 includes a transmission gear 232 located at the center of the transmission gears 231, 232, and 233 constituting the gear transmission mechanism 230 and a transmission gear 233 located at the lowermost position. And are provided so as to overlap in a side view.

  In this case, with respect to the length (height) H of the rib 244 in the axial direction of the output shaft 220, the rib extends beyond both one end and the other end of the transmission gears 232 and 233 adjacent to the rib 244 in the rotational axis direction. 244 is provided. In other words, the axial length W of the transmission gears 232 and 233 is positioned within the height H of the rib 244 extending from the second end surface 242 of the gear case 240 to the first end surface 241 side (flywheel housing 13 side). And is supported by the gear case 240.

When the stored oil Q in the gear housing 240a is agitated by the gear transmission mechanism 230, the stored oil Q is urged in the radial direction of the transmission gears 232 and 233 by the rotation of the transmission gears 232 and 233 (gears 232 and 233). The stored oil Q is scattered in the radial direction of the gears 232 and 233 by the centrifugal force generated by the rotation of In contrast, by providing the ribs 244 by overlapping the transmission gears 232 and 233, even if the stored oil Q is scattered by the rotation of the transmission gears 232 and 233, the scattered high-temperature stored oil Q is not stored in the oil storage section. Direct entry to 245a is prevented.
Therefore, the temperature increase of the oil Q stored in the oil reservoir 245a can be prevented by more effectively suppressing the stirring action of the oil stored in the oil reservoir 245a, and the entire gear case 240 can be prevented. The temperature rise of the stored oil Q can be more effectively suppressed.
In the present embodiment, an auxiliary pump unit 280 is attached to the transmission unit 200. That is, the region of the transmission unit 200 corresponding to the gear transmission mechanism 230 is an auxiliary pump unit 280 (auxiliary pump main body + auxiliary pump main body that is operatively driven by the downstream end portion of the input shaft 210 in the transmission direction. The auxiliary pump mounting region 200a to which the surrounding auxiliary pump case) is mounted and the output region 200b from which the end of the output shaft 220 on the downstream side in the transmission direction is projected are configured. Here, as shown in FIG. 6, an auxiliary pump mounting area 200a is provided around the output area 200b.
Here, the auxiliary pump unit 280 is a hydraulic oil supply pump for various hydraulic mechanisms (for example, a hydraulic transmission 311 and a PTO clutch mechanism 320, a power steering valve device, etc.) in the transmission 3 following the output shaft 220. Used as In the present embodiment, as shown in the drawing, two hydraulic gear pumps are connected as the auxiliary pump unit 280, but the present invention is not limited to this.

As shown in FIGS. 3 and 6, the auxiliary pump unit 280 includes a drive shaft 281 that is operatively connected to the input shaft 210, and drive-side gears 282a and 282b that are provided on the drive shaft 281 so as not to rotate relative to each other. The driven side gears 283a and 283b meshing with the driving side gears 282a and 282b, the driving shaft 281 are rotatably supported around the axis, and the driving side gears 282a and 282b and the driven side gears 283a and 283b are accommodated. And a pump case 284.
As shown in FIGS. 5 and 7, the pump case 284 includes an input port 284a fluidly connected to a hydraulic oil storage tank (not shown) via an input side pipe, and the drive side gear 282 and Input ports 284a and 284b arranged upstream of the rotation direction of the gears 282 and 283 (in the direction of arrow B in FIG. 6) across the meshing point R of the driven side gear 283, and output side piping ( Output ports 285a and 285b that are fluidly connected to each other via an unillustrated output port 285a disposed on the downstream side in the rotational direction B of the gears 282a and 283a (282b and 283b) with the meshing point R interposed therebetween. , 285b.

With such a configuration, the hydraulic gear pump 280 receives hydraulic oil from the input ports 284a and 284b and operates from the output ports 285a and 285b by the rotational operation of the gears 282a and 283a (282b and 283b). Oil is discharged, the hydraulic oil discharged from the output ports 285a and 285b, and sent through the output side piping is used as the various hydraulic mechanisms in the transmission 3 (for example, the hydraulic transmission 311 and the PTO clutch mechanism 320, It is used as hydraulic oil for power steering valve devices.
The auxiliary pump unit 280 may be provided near the lower side of the steering steering 8 (preferably directly below the steering steering 8). By doing so, the hydraulic piping from the auxiliary pump unit 280 to the power steering valve device can be made as short as possible.

When such an auxiliary pump unit 280 is provided, the bulging portion 245 includes the auxiliary pump unit 280 attached to the second end portion 240b of the gear case 240 and the output shaft 220 (and the output shaft) protruding from the second end portion 240b. 220 is provided at a position avoiding the downstream end of the transmission direction of the transmission shaft 17) with the universal joint that is attached to 220 so as not to rotate relative thereto.
Therefore, the bulging portion 245 can be provided without interfering with other components provided at the second end portion 240b of the gear case 240.

As mentioned above, although embodiment which concerns on this invention was described, this invention is not limited to the said embodiment, A various improvement, change, and correction are possible within the range which does not deviate from the meaning.
For example, in the present embodiment, the rib 244 is spaced apart from the first end surface 241 in the entire region (oil circulation is possible in the entire region of the rib 244), but is not limited to this. Oil distribution may be possible only at the position.

FIG. 8 is a schematic front view (a diagram corresponding to the IV-IV end view of FIG. 3 in the above embodiment) centering on a transmission unit portion in a working vehicle according to another embodiment of the present invention. The same components as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the example of FIG. 8, the gear housing portion 240a and the oil storage portion 245a are provided on the upper end side and the lower end side of the rib 244 with reference to the state where the gear case 244 is mounted on the flywheel housing 13 as an attachment site. Are provided with oil circulation portions 244a and 244b. In addition, a guide rib 244c is provided above the oil circulation portion 244a on the upper end side and directed away from the oil circulation portion 244a on the upper end side as the transmission gear 232 is approached.

  In this case, the gear accommodating portion 240a and the oil storing portion 245a are configured such that the oil circulation portion 244a provided on the upper end side of the rib 244 and the oil provided on the lower end side based on the state where the gear case 240 is attached to the flywheel housing 13. It communicates through the distribution part 244b. Note that other portions of the rib 244 extend from the first end 240a to the second end 240b.

  At this time, when the transmission gear 232 of the gear transmission mechanism 230 rotates in the direction of the arrow D in FIG. 8, the stored oil Q in the gear accommodating portion 240a is pumped up as described above. The stored stored oil Q leaves the oil level L, scatters in the tangential direction of the transmission gear 232, a part of which hits the guide rib 244 c and falls downward. Thus, the scattered stored oil Q enters the oil storing section 245a from the oil circulation section 244a on the upper end side of the rib 244 below the guide rib 244c. The stored oil Q that has entered the oil storage section 245a has its stirring action suppressed by the ribs 244, so that the temperature rise is suppressed and the natural oil is gradually cooled gradually. And since the oil level of the oil storage part 245a rises with respect to the oil level in the gear accommodating part 240a by the stored oil Q which entered from the oil circulation part 244a on the upper end side, the stored oil Q (cooling) in the oil storage part 245a The stored oil Q) enters the gear accommodating portion 240a from the oil circulation portion 244b on the lower end side of the rib 244.

In this way, the stored hot water Q in the gear housing portion 240a that has been lifted by the gear transmission mechanism 230 and has risen in temperature enters the oil storage portion 245a side from the oil circulation portion 244a on the upper end side of the rib 244, while the gear housing portion. The stored oil Q having a temperature lower than that of the stored oil Q in 240a enters the gear housing section 240a side from the oil circulation section 244b on the lower end side of the rib 244. Thereby, the temperature rise of the stored oil Q in the gear accommodating portion 240a is achieved while efficiently circulating the stored oil having a high temperature and the low temperature stored oil to cool the stored oil Q that has entered the oil storing portion 245a. It can be effectively prevented.
Further, by providing the guide rib 244c so as to be away from the upper oil circulation portion 244a as it approaches the transmission gear 232, the oil Q scattered by the rotation of the transmission gear 232 is transferred from the upper oil circulation portion 244a to the oil storage portion. 245a can be effectively introduced. In addition, although the guide rib 244c is provided so that one end may contact the surrounding wall 243 of the gear case 240, it is not restricted to this, The guide rib 244c does not need to contact the surrounding wall 243. Further, the same effect can be obtained even when the shape of the peripheral wall 243 is such that the shape of the peripheral wall 243 increases away from the oil circulation portion 244a on the upper end side as it approaches the transmission gear 232 above the rib 244.

1 is a schematic side view of a working vehicle (here, a riding tractor) to which an example of a transmission unit according to an embodiment of the present invention is applied. It is a transmission schematic diagram in the work vehicle of FIG. It is a vertical side view of the vicinity of the transmission unit in the working vehicle of this embodiment. FIG. 4 is an IV-IV end view of FIG. 3. FIG. 4 is a schematic cross-sectional view centering on a transmission unit portion in the working vehicle of the present embodiment, and is a schematic cross-sectional view with a plane displaced from the cross-section of FIG. 3 to the other side in the vehicle width direction as a cross-section. It is a schematic back perspective view centering on the transmission unit part in the working vehicle of this embodiment. It is a schematic front perspective view centering on the transmission unit part in the working vehicle of this embodiment. It is a schematic front view which shows centering on the transmission unit part in the working vehicle of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Drive source 200 ... Transmission unit 210 ... Input shaft 220 ... Output shaft 230 ... Gear transmission mechanism 231, 232, 233 ... Transmission gear 240 ... Gear case 240a ... Gear accommodating part 241 ... 1st end surface 242 ... 2nd end surface 244 ... Rib 244a, 244b ... oil circulation part 245 ... bulge part 245a ... oil storage part Q ... stored oil

Claims (4)

An oil storage gear case having first and second end surfaces facing each other, and an end portion on the downstream side in the transmission direction supported by the first end surface in a state where the upstream end portion in the transmission direction can be operatively connected to the drive source The input shaft supported by the second end surface, the end portion on the upstream side in the transmission direction is supported by the first end surface, and the end portion on the downstream side in the transmission direction can output rotational power to the second end surface. A transmission unit comprising a supported output shaft and a gear transmission mechanism for transmitting power from the input shaft to the output shaft;
The gear case is provided with a rib that divides an internal space into a gear accommodating portion that accommodates the gear transmission mechanism and an oil reservoir that allows oil to flow with respect to the gear accommodating portion. Transmission unit.   2. The transmission unit according to claim 1, wherein the rib is provided so as to overlap at least a lowermost gear among the gears constituting the gear transmission mechanism in a side view.   With reference to the state in which the gear case is mounted on the attachment site, an oil circulation portion that communicates the gear housing portion and the oil storage portion is provided on the upper end side and the lower end side of the rib. The transmission unit according to claim 1 or 2.   4. The transmission unit according to claim 1, wherein the second end surface of the gear case has a region corresponding to the oil storage portion bulged downstream in the transmission direction of the output shaft.

Images