JP2005248991A - Transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent lowering of transmission efficiency of a traveling system transmitting mechanism due to stored oil even if enough quantity of oil is stored in a housing and further to prevent an out-of-oil phenomenon even if the stored oil is taken out from an arbitrary part in a traveling system chamber. <P>SOLUTION: The housing includes: the traveling system chamber storing the traveling system transmission mechanism; and a reservoir chamber liquid-tightly separated from the traveling system chamber by a partition. Some of the stored oil is transferred from the traveling system chamber to the reservoir chamber by the rotary motion of the traveling system transmission mechanism. The partition is provided with an opening and closing device for keeping the state of separating the traveling system chamber from the reservoir chamber while the traveling system transmission mechanism is rotating, and communicating the traveling system chamber with the reservoir chamber while the traveling system transmission mechanism is being stopped. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transmission having a housing that houses a traveling system transmission mechanism and that can store oil.

It has been conventionally known that hydraulic oil used in various hydraulic mechanisms is stored in a housing that houses a traveling system transmission mechanism from a driving source to driving wheels.
Thus, by using the housing also as a hydraulic oil storage space, it is possible to reduce the cost and size of the transmission itself by eliminating or minimizing the storage tank.

However, the conventional transmission is insufficient in the following points.
That is, the oil stored in the housing is used as hydraulic oil for various hydraulic mechanisms provided in the vehicle. Therefore, when the housing is also used as a storage tank, it is necessary to store a sufficient amount of oil in the housing so that the hydraulic mechanism does not run out of oil.
On the other hand, the oil stored in the housing becomes a load for the traveling transmission mechanism housed in the housing. Therefore, storing a large amount of oil in the housing is not preferable from the viewpoint of transmission efficiency of the traveling system transmission mechanism.

As described above, it is preferable to store a large amount of oil in the housing from the viewpoint of supplying hydraulic oil to the hydraulic mechanism. On the other hand, from the viewpoint of driving efficiency of the traveling transmission mechanism, the stored oil in the housing. There is a conflicting desire that it is preferable to minimize the amount.
In this regard, the conventional transmission is not fully considered.

  The present invention has been made in view of the prior art, and in a transmission including a housing that accommodates a traveling transmission mechanism and can store hydraulic oil, a sufficient amount of hydraulic oil is placed in the housing. One object is to provide a transmission that can effectively prevent deterioration of the transmission efficiency of the traveling transmission mechanism even if it is stored.

In order to achieve the above object, the present invention includes a travel system transmission mechanism that transmits a driving force from a drive source to a drive axle, and a housing that houses the travel system transmission mechanism and that can store oil. Provide a transmission equipped with.
The housing includes a traveling system chamber that houses the traveling system transmission mechanism, and a reservoir chamber that is liquid-tightly separated from the traveling system chamber by a partition wall.
The reservoir chamber is configured such that a part of the stored oil is transferred from the traveling system chamber by the rotational motion of the traveling system transmission mechanism.
The partition maintains the separated state of the traveling system chamber and the reservoir chamber while the traveling system transmission mechanism is rotating, and the traveling system chamber and the reservoir chamber when the traveling system transmission mechanism is stopped. An opening / closing device that communicates with each other.

In one aspect, the opening / closing device takes an opening formed in the partition so as to communicate the traveling system chamber and the reservoir chamber, a closed position that closes the opening, and an open position that opens the opening. An opening / closing member to be obtained, a biasing member that biases the opening / closing member toward the open position, and a pushing mechanism that pushes the opening / closing member toward the closing position against the biasing force of the biasing member. Can have.
The pushing mechanism is configured to push the opening / closing member by using a hydraulic pressure of a hydraulic circuit in the transmission.

In the one aspect, the pressing mechanism includes a pressure oil supply line that applies pressure oil of the hydraulic circuit to the opening and closing member so that the opening and closing member is pushed to the closed position by the pressure oil of the hydraulic circuit; And a switching valve interposed in the pressure oil supply line.
The switching valve is configured to communicate and block the pressure oil supply line when the traveling transmission mechanism rotates and stops, respectively.
When the transmission further includes a PTO transmission mechanism that outputs a driving force from the drive source to the outside of the housing, the pressure oil supply line is, for example, a hydraulic oil from a hydraulic circuit in the PTO transmission mechanism. May be configured to branch out.

In the case where the traveling system transmission mechanism has a differential gear device including a ring gear that rotates about a rotational axis along the vehicle width direction, the partition wall is configured so that the traveling system chamber and the reservoir chamber are located on the other side from the vehicle longitudinal direction. It extends in the vehicle width direction so as to be arranged in series along the side.
In such an aspect, the partition wall is configured such that part of the stored oil in the traveling system chamber flows into the reservoir chamber by a scraping action accompanying the rotational movement of the ring gear.

The traveling system transmission mechanism includes a differential gear device including a ring gear that rotates about a rotation axis along a vehicle width direction, and the partition wall is configured so that the traveling system chamber and the reservoir chamber extend from one side to the other side in the longitudinal direction of the vehicle. And a part of the stored oil in the traveling system chamber flows into the reservoir chamber by a scraping action accompanying the rotational movement of the ring gear. In this aspect, for example, the opening / closing device includes an opening formed in the partition so as to communicate the traveling system chamber and the reservoir chamber, a closed position that closes the opening, and an open position that opens the opening. And an urging member that urges the opening / closing member toward the open position.
In this aspect, the opening / closing member is configured to be pushed to the closed position against the urging force of the urging member by the flow of stored oil accompanying the rotational movement of the ring gear.

As described above, according to the transmission according to the present invention, even when a sufficient amount of oil is stored in the housing, it is possible to effectively prevent the transmission efficiency of the traveling transmission mechanism from being deteriorated by the stored oil.
Further, when the traveling system transmission mechanism is stopped, the oil can be quickly returned from the reservoir chamber to the traveling system chamber. Therefore, the oil shortage phenomenon can be prevented as much as possible even if the stored oil is taken out from an arbitrary place in the traveling system chamber.

Embodiment 1 FIG.
Hereinafter, preferred embodiments of a transmission according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a transmission schematic diagram of a transmission 1A according to the present embodiment.

  As shown in FIG. 1, the transmission 1A includes a traveling system transmission mechanism that transmits a driving force from a driving source 2 (see FIG. 3) to a driving axle 100, and a housing 10 that houses the traveling system transmission mechanism. ing.

The traveling system transmission mechanism includes a forward / reverse switching hydraulic mechanism 110, a transmission hydraulic mechanism 120 such as HI / LO, a mechanical main transmission mechanism 130, a mechanical auxiliary transmission mechanism 140, and a differential gear mechanism 150. I have.
In the present embodiment, the traveling system transmission mechanism further includes a four-wheel driving force extraction hydraulic mechanism 160.
The four-wheel drive force extraction hydraulic mechanism 160 is used when driving other wheels (not shown) in addition to the drive wheels 100 (rear wheels in the illustrated embodiment) that are always driven. Can be selectively attached to the housing 10.

The housing 10 can store oil in at least a part of the internal space.
In the present embodiment, the housing 10 includes a front housing 20, a middle housing 30, and a rear housing 40 connected in series along the longitudinal direction of the vehicle.
The front housing 20, the middle housing 30, and the rear housing 40 are connected to each other so that oil can flow. That is, each of these housings is provided with an opening at an opposing end portion, and oil can freely flow through the opening.

  More specifically, the front housing 20 is located in the dry chamber 21 that houses the flywheel 250 operatively connected to the drive source 2, and is located downstream of the dry chamber 21 in the transmission direction, and the forward / reverse switching hydraulic mechanism. 110 and a first oil chamber 22 that houses the transmission hydraulic mechanism 120.

The middle housing 30 includes a second oil chamber 31 that houses the main transmission mechanism, and a third oil chamber 32 that houses the auxiliary transmission mechanism.
The four-wheel driving force extraction hydraulic mechanism 160 is detachably attached to the middle housing 30.

The rear housing 40 includes a fourth oil chamber 41 that accommodates the differential gear mechanism 150 and a PTO chamber 42 that accommodates a PTO transmission unit 330 of a PTO transmission mechanism described later.
Specifically, the rear housing 40 has a partition wall 43, and the fourth oil chamber 41 and the PTO system chamber 42 are liquid-tightly separated by the partition wall 43.

  In the present embodiment, the space formed by the first oil chamber 22, the second oil chamber 31, the third oil chamber 32, the fourth oil chamber 41, and the PTO chamber 42 in the internal space of the housing 10. However, it is set as the storage space which can store hydraulic fluid.

The transmission 1A according to the present embodiment includes a PTO transmission mechanism that outputs the driving force from the drive source 2 to the outside in addition to the traveling transmission mechanism.
The PTO transmission mechanism is disposed between a PTO transmission shaft 310 operatively connected to the drive source 2, a PTO output shaft 320 that outputs power to the outside, and the PTO transmission shaft 310 and the PTO output shaft 320. The PTO transmission unit 330 is provided.

One end portion of the PTO transmission shaft 310 is operatively connected to the drive source 2 in the front housing 20, and the other end portion penetrates the front housing 20 and the middle housing 30 to form the rear housing. 40 PTO chambers 42 are reached.
In the present embodiment, a part of the transmission shaft in the traveling transmission mechanism is a hollow shaft, and the PTO transmission shaft 310 is inserted through the hollow shaft to reduce the size of the transmission itself.

The PTO output shaft 320 is supported by the housing 10 such that one end extends into the PTO chamber 42 and the other end extends outward from the housing 10.
In the present embodiment, the housing 10 further includes a lid member 50 that closes the rear opening of the rear housing 40, and the PTO output shaft 320 is supported by the lid member 50 and the partition wall 43. Has been.

The PTO transmission unit 330 operatively connects the PTO transmission shaft 310 and the PTO output shaft 320 in the PTO chamber 42.
Preferably, the PTO transmission unit 330 may include a hydraulic PTO clutch 335 that turns on / off power transmission from the PTO transmission shaft 310 to the PTO output shaft 320.
More preferably, the PTO transmission unit 330 may include a hydraulic PTO brake (not shown) that operatively applies a braking force to the PTO output shaft 320 in conjunction with the OFF operation of the hydraulic PTO clutch 335.

Thus, in the transmission 1 </ b> A according to the present embodiment, the storage formed by the first oil chamber 22, the second oil chamber 31, the third oil chamber 32, the fourth oil chamber 41, and the PTO system chamber 42. In the space, a traveling transmission mechanism and a PTO transmission unit 330 are accommodated on one side and the other side of the partition wall 43, respectively.
That is, the partition wall 43 stores the oil storage space in the traveling system chamber 11 in which the traveling system transmission mechanism is accommodated and the PTO transmission unit, and the traveling system chamber 11 is liquid-tight. The PTO system chamber 42 acting as the separated reservoir chamber 12 is separated.

  In addition to such a configuration, the transmission 1A according to the present embodiment further has a portion of the oil stored in the traveling system chamber 11 due to the rotational motion of the rotating body in the traveling system transmission mechanism. (In this embodiment, it is configured to be transferred to the PTO system chamber 42).

FIG. 2 shows an enlarged schematic view of a portion II in FIG.
As shown in FIG. 2, the partition wall 43 is disposed in proximity to the ring gear 151 of the differential gear mechanism 150, and a part of the stored oil scraped up by the rotation of the ring gear 151 is part of the PTO chamber 42. It is said to be high enough to enter.
That is, in the partition wall 43, oil (see the broken line arrow F) scraped up by the rotation of the ring gear 151 (see arrow D) is transferred from the traveling system chamber 11 to the PTO system chamber 42 across the partition wall 43. Further, a relative position with respect to the ring gear 151 is set.

Further, the partition wall 43 is provided with an opening / closing device 60.
The opening / closing device 60 maintains the separated state of the traveling system chamber 11 and the reservoir chamber 12 while the traveling system transmission mechanism is rotating, and the traveling system chamber 11 when the traveling system transmission mechanism is stopped. And it is comprised so that the said reservoir | reserver chamber 12 may be connected.

  Specifically, the opening / closing device 60 includes an opening 61 formed in the partition wall 43 so as to communicate the traveling system chamber 11 and the reservoir chamber 12, and a closed position for closing the opening 61 (see FIG. 2 (a)). ) And an open position that opens the opening 61 (see FIG. 2B), an urging member 63 that urges the open / close member 62 toward the open position, and the open / close member 62 And a pushing mechanism 70 that pushes against the urging force of the urging member 63 toward the closing position.

  In the present embodiment, as shown in FIG. 2, the opening / closing member 62 is a rod-like member inserted through the opening 61 so as to be movable in the axial direction, and is in a first position in the axial direction (FIG. 2 (a )), The opening 61 is closed, and at the second position in the axial direction (see FIG. 2B), the opening 61 is opened.

For example, the rod-shaped member has a grooved portion in which the first end portion 62a on the traveling system chamber side has a spline groove on the outer peripheral surface, and the traveling system chamber 11 sandwiches the first end portion 62a. A portion 62 b adjacent to the opposite side has the same diameter as the opening 61 or a larger diameter than the opening 61.
For example, the urging member 63 in the form of a coil spring or the like is arranged to urge the opening / closing member 62 toward the second axial position (see FIG. 2B).
Of course, instead of the grooved portion, the first end portion 62a may be a smaller diameter portion having a smaller diameter than the opening 61, or one end portion of the first end portion 62a communicates with the traveling system chamber 11. However, it is also possible to form an axial hole whose other end communicates with the PTO chamber 12.

The pushing mechanism 70 is configured to forcibly position the opening / closing member 62 located at the closed position by the biasing member 63 in the normal state.
FIG. 3 shows a hydraulic circuit diagram of the transmission according to the present embodiment.
As shown in FIG. 3, the transmission 1A includes a hydraulic circuit 110A for the forward / reverse switching hydraulic mechanism 110, a hydraulic circuit 120A for the transmission hydraulic mechanism 120, and a hydraulic pressure for the four-wheel driving force extraction hydraulic mechanism 160. A circuit 160A and a hydraulic circuit 355A for the hydraulic PTO clutch device 355 are provided.
Note that reference numerals 310A and 320A in FIG. 3 denote a power steering hydraulic circuit and a work machine lift hydraulic circuit, respectively. Reference numeral 150A denotes a differential lock hydraulic circuit.

Specifically, the push mechanism 70 pushes the opening / closing member 62 toward the open position using the hydraulic pressure of the pressure oil from the hydraulic pumps 3A to 3C operatively driven by the drive source 2. It is configured.
In the present embodiment, as shown in FIG. 3, the push mechanism 70 is arranged so that the opening / closing member 62 is pushed to the closed position by the pressure oil of the hydraulic circuit 355A for the hydraulic PTO clutch device. The pressure oil supply line 71 communicates with the hydraulic circuit 355 </ b> A and the opening / closing member 62, and the switching valve 72 is inserted in the pressure oil supply line 71.

Specifically, one end of the pressure oil supply line 71 is communicated with the hydraulic circuit 355A.
The other end portion of the pressure oil supply line 71 is configured such that the opening / closing member 62 is pushed to the closed position against the urging force of the urging member 63 by the pressure oil flowing through the pressure oil supply line 71. In addition, the hydraulic chamber 65 communicates with the hydraulic chamber 65.

The switching valve 72 is configured to communicate and block the pressure oil supply line 71 when the traveling system transmission mechanism rotates and stops, respectively.
That is, when the traveling transmission mechanism performs a rotational motion, the switching valve 72 brings the pressure oil supply line 71 into a communicating state. In this state, the pressure oil acts on the opening / closing member 62 via the pressure oil supply line 71, whereby the opening / closing member 62 is pushed to the closing position against the urging force of the urging member 63. Is done. Therefore, the traveling system chamber 11 and the PTO system chamber 12 are separated in a liquid-tight manner.
On the other hand, when the traveling transmission mechanism stops, the switching valve 72 shuts off the pressure oil supply line 71. In this state, the opening / closing member 62 is held in the open position by the urging force of the urging member 63. Therefore, the traveling system room 11 and the PTO system room 12 are in communication.

In the transmission 1A having such a configuration, the following effects can be obtained.
That is, in the transmission 1A, as described above, from the traveling system chamber 11 in which the traveling system transmission mechanism is accommodated to the PTO system chamber 42 acting as the reservoir chamber 12 by the rotational motion of the rotating body in the traveling system transmission mechanism. Part of the stored oil is transferred.
Therefore, even if a sufficient amount of oil is stored in the housing 10, it is possible to effectively prevent the transmission efficiency of the traveling system transmission mechanism from deteriorating.

  Further, when the traveling system transmission mechanism is stopped, as described above, the reservoir chamber 12 and the traveling system chamber 11 are communicated with each other by the opening / closing mechanism 60, whereby the traveling system transmission mechanism is operated. The oil shortage phenomenon at the start can be effectively prevented.

In other words, during the rotation of the traveling system transmission mechanism, a part of the stored oil in the traveling system chamber 11 is transferred to the reservoir chamber 12, so that the oil level OL (1) of the traveling system chamber 11 is stored in the reservoir chamber 12. The oil level is lower than OL (2).
Normally, the storage oil is taken out from a predetermined part of the traveling system chamber 11 from the viewpoint of the filter storage space and the like, and therefore when the oil level OL (1) of the traveling system chamber 11 is lowered, the stored oil is taken out. There is a risk of air mixing.
On the other hand, in the transmission 1A according to the present embodiment, as described above, when the traveling system transmission mechanism is stopped, the reservoir chamber 12 communicates with the traveling system chamber 11, and the oil level in both chambers is quickly increased. It is configured to be uniform.
Therefore, it is possible to effectively prevent the oil shortage phenomenon at the start of operation of the traveling system transmission mechanism.

  In the present embodiment, the pressure oil supply line 71 is configured to communicate with the PTO clutch hydraulic circuit 355A, but naturally the pressure oil for pushing the opening / closing member is taken out from another oil passage. It is also possible to configure.

In the present embodiment, the switching valve 72 is inserted in the pressure oil supply line 71, but the switching valve 72 can be omitted.
That is, each hydraulic circuit in the transmission takes a predetermined set pressure while the hydraulic power source such as the hydraulic pumps 3A to 3B is operating, and takes a normal pressure lower than the set pressure when the hydraulic power source is stopped.
Therefore, by making the urging force of the urging member 63 weaker than the pushing force by the set pressure and stronger than the pushing force by the normal pressure, the above-described effect can be obtained without the switching valve 72. Can be obtained.

Embodiment 2. FIG.
Hereinafter, another embodiment of the transmission according to the present invention will be described with reference to FIG.
Note that the same or equivalent members as those in the first embodiment are given the same reference numerals or the same reference numerals with a dash, and detailed description thereof is omitted.

  In the first embodiment, the opening / closing member 62 is pushed toward the closing position by using the hydraulic pressure of the hydraulic circuit. However, in the present embodiment, the opening / closing member is driven by the flow of stored oil. It is configured to push 262 toward the closed position.

Specifically, the transmission 1 </ b> B includes an opening / closing device 260 instead of the opening / closing device 60.
The opening / closing device 260 includes an opening 61 formed in the partition wall 43, a closing position for closing the opening 61 (see FIG. 4A), and an opening position for opening the opening 61 (see FIG. 4B). And an urging member (not shown) for urging the opening / closing member 262 toward the open position.

As shown in FIG. 4, the opening / closing member 262 is disposed in the traveling system chamber 11 so as to be positioned between the ring gear 151 and the partition wall 43.
Specifically, the opening / closing member 262 includes a main body portion 262a that can swing around a pivot shaft 261 that is parallel to the rotation axis of the ring gear 151, and a seal portion that protrudes from the main body portion 262a toward the partition wall 43. 262b.

The main body 262a is urged in a direction (the clockwise direction in FIG. 4) in which the seal portion 262b is separated from the partition wall 43 by the urging force of the urging member.
In the present embodiment, the urging member is a winding spring wound around the pivot shaft 261.
The main body portion 262a receives a flow of stored oil (arrow A in FIG. 4) accompanying the rotation of the ring gear 151, and the seal portion 262b approaches the partition wall 43 (counterclockwise direction in FIG. 4). It is comprised so that it may rock | fluctuate to.
That is, the main body portion 262a is positioned at the open position by the urging force of the urging member when the ring gear 151 is stopped, and the ring gear 151 is rotated when the ring gear 151 is rotating. It is located at the closed position by the flow of stored oil accompanying the rotation of 151.

The seal portion 262b is shaped and dimensioned to close the opening 61 when the main body portion 262a is located at the closed position.
Note that reference numeral 262c in FIG. 4 is a stopper provided in the main body portion 262a, and delimits the swing range of the main body portion 262a by the biasing force of the biasing member.

  In this embodiment as well, as in the first embodiment, even if a sufficient amount of oil is stored in the housing 10, the transmission efficiency of the traveling system transmission mechanism is prevented from deteriorating. In addition, it is possible to effectively prevent the oil shortage phenomenon when taking out the stored oil from the traveling system chamber.

  In each of the above embodiments, the PTO system chamber 42 is used as the reservoir chamber 12 and a part of the stored oil in the traveling system chamber 11 is transferred to the PTO system chamber 42. However, the present invention is such. The form is not limited. That is, various spaces can be used as the reservoir chamber as long as the stored oil transferred from the traveling system chamber 11 can be reserved.

FIG. 1 is a transmission schematic diagram of a transmission according to an embodiment of the present invention. Fig.2 (a) is an enlarged schematic diagram of the II part in FIG. 1, and has shown the case where the switchgear is in the obstruction | occlusion state. FIG. 2B is an enlarged schematic diagram of the II part in FIG. 1 and shows a case where the opening / closing device is in an open state. FIG. 3 is a hydraulic circuit diagram of the transmission shown in FIG. FIG. 4A is a schematic diagram of a partial longitudinal section of a transmission according to another embodiment of the present invention, and shows a case where the opening / closing device is in a closed state. FIG. 4B is a schematic diagram of a partial longitudinal section of a transmission according to another embodiment of the present invention, and shows a case where the opening / closing device is in an open state.

Explanation of symbols

1A, 1B Transmission 2 Drive source 10 Housing 11 Traveling system chamber 12 Reservoir chamber 42 PTO system chamber 43 Bulkhead 60 Opening and closing device 61 Opening 62 Opening and closing member 63 Energizing member 70 Pushing mechanism 71 Pressure oil supply line 72 Switching valve 150 Differential gear device 151 Ring gear

Claims (5)

A transmission including a traveling system transmission mechanism that transmits a driving force from a driving source to a driving axle; and a housing that stores the traveling system transmission mechanism and that can store oil;
The housing includes a traveling system chamber that houses the traveling system transmission mechanism, and a reservoir chamber that is liquid-tightly separated from the traveling system chamber by a partition wall;
The reservoir chamber is configured such that a part of the stored oil is transferred from the traveling system chamber by a rotational movement of the traveling system transmission mechanism.
The partition maintains the separated state of the traveling system chamber and the reservoir chamber while the traveling system transmission mechanism is rotating, and the traveling system chamber and the reservoir chamber when the traveling system transmission mechanism is stopped. A transmission characterized in that an opening and closing device is provided for communicating with each other. The opening / closing device includes an opening formed in the partition so as to communicate the traveling system chamber and the reservoir chamber;
An opening and closing member capable of taking a closing position for closing the opening and an opening position for opening the opening;
A biasing member that biases the opening and closing member toward the open position;
A pushing mechanism that pushes the opening / closing member toward the closing position against the urging force of the urging member;
The transmission according to claim 1, wherein the push mechanism is configured to push the opening / closing member using a hydraulic pressure of a hydraulic circuit in the transmission. The pressing mechanism includes a pressure oil supply line that causes the pressure oil of the hydraulic circuit to act on the opening and closing member so that the opening and closing member is pushed to the closed position by the pressure oil of the hydraulic circuit;
A switching valve inserted in the pressure oil supply line,
The transmission according to claim 2, wherein the switching valve is configured to communicate and block the pressure oil supply line, respectively, when the traveling system transmission mechanism is rotated and stopped. The traveling system transmission mechanism has a differential gear device including a ring gear that rotates around a rotation axis along the vehicle width direction,
The partition wall extends in the vehicle width direction so that the traveling system chamber and the reservoir chamber are arranged in series from one side to the other side in the vehicle longitudinal direction,
4. The structure according to claim 1, wherein a part of the stored oil in the traveling system chamber flows into the reservoir chamber by a scraping action associated with the rotational movement of the ring gear. 5. Transmission. The traveling system transmission mechanism has a differential gear device including a ring gear that rotates around a rotation axis along the vehicle width direction,
The partition wall extends in the vehicle width direction so that the traveling system chamber and the reservoir chamber are arranged in series from one side to the other side in the vehicle longitudinal direction,
A part of the stored oil in the traveling system chamber flows into the reservoir chamber by a scraping action accompanying the rotational movement of the ring gear,
The opening / closing device includes an opening formed in the partition so as to communicate the traveling system chamber and the reservoir chamber;
An opening and closing member capable of taking a closing position for closing the opening and an opening position for opening the opening;
A biasing member that biases the opening and closing member toward the open position;
2. The transmission according to claim 1, wherein the opening / closing member is pushed to a closed position against a biasing force of the biasing member by a flow of stored oil accompanying a rotational movement of the ring gear.

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