JPH05149412A - Breather structure of transmission - Google Patents

Abstract

PURPOSE:To give a breather function in a simple and compact structure by utilizing a part to compose the select return mechanism of a transmission. CONSTITUTION:In a transmission provided with a select return mechanism 50, housings 51a and 51b are used as a breather chamber concurrently by forming a passage 62 to communicate the housings 51a and 51b to the atmosphere, in a transmission case 1, as well as communicating the housings 51a and 51b for select return to the inside of the transmission case 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breather structure for releasing internal pressure in a transmission having a select / return mechanism.

[0002]

2. Description of the Related Art Generally, a manual type transmission has a plurality of gear trains for gear shifting arranged on a main shaft, a counter shaft, etc., and a power transmission between one gear and the shaft of each gear train. A synchronizing device for performing the connection and disconnection, and a shift system such as a shift rod for operating the synchronizing device according to an operation of a shift operating portion such as a change lever are provided.

Further, in this type of transmission, normally,
A select return mechanism is provided for returning the shift system to a fixed basic position when in neutral. For example, in the device disclosed in Japanese Utility Model Laid-Open No. 61-143220, a pair of piston members (plungers) arranged on both sides of the lower end portion of the shift lever and each piston member on both side surfaces of the lower end portion of the shift lever. There is provided a mechanism that has a spring that urges the shift lever and applies a return force to the basic position to the shift lever.

In addition to this, as a select return mechanism, a piston rod and springs for urging the piston rod are arranged on both sides of a control rod provided in the transmission case and interlocked with a shift lever. There are rods that are designed to exert a return force to the basic position.

[0005]

By the way, in this type of transmission, the pressure inside the transmission case fluctuates due to temperature changes while avoiding the release of oil mist from the inside of the transmission case to the outside. In order to allow the flow of air between the outside and the outside, a breather chamber that communicates with the inside of the transmission case and communicates with the outside air is provided in the transmission case in the past. However, this breather chamber is provided separately from the select return mechanism and the like, and there is room for improvement in terms of simplification and compactness of the structure of the transmission.

In view of the above circumstances, it is an object of the present invention to provide a breather structure for a transmission, which has a breather function with a simple and compact structure by utilizing a portion constituting a select return mechanism. ..

[0007]

To achieve the above object, the present invention has a piston member and a biasing member housed in a member housing for select return, and is biased by the biasing member at the time of neutral. In the transmission including the select return mechanism configured to return the shift system to the basic position by the piston member, the select return member accommodating chamber is communicated with the inside of the transmission case, and the accommodating chamber is exposed to the atmosphere. A passage for communication is formed in the transmission case, and the accommodation chamber is also used as the breather chamber.

In this structure, a pair of select return member accommodating chambers are provided, and a communication passage for communicating the two chambers with each other and a passage for communicating one chamber with the atmosphere can be formed in the transmission case. preferable.

[0009]

According to the above construction, the accommodating chamber for accommodating the piston member and the spring of the select / return mechanism effectively functions as a breather chamber, and an air responsive to the pressure difference between the transmission case and the outside air is passed through this chamber. Is distributed.

[0010]

Embodiments of the present invention will be described with reference to the drawings.
FIGS. 1 and 2 show an example of a transmission to which the present invention is applied. In these drawings, reference numeral 1 denotes a transmission case that also serves as a clutch housing, which is divided into front and rear parts in advance, and a front case 11 and a rear case 12 thereof. And are joined together by their respective flanges, and are joined by a plurality of bolts. The transmission case 1 shown in the figure has a cone shape in which the whole is narrowed toward the rear side, and is formed in a tubular shape having a substantially constant cross section in a predetermined range of an intermediate portion including a joining portion of the front and rear cases 11 and 12. There is. The front case 11 integrally includes a clutch housing portion 111 and a transmission housing portion 112.

An input shaft 2 is provided inside the transmission case 1.
1, a transmission 2 including members such as a main shaft 22 and a counter shaft 23, and a clutch 3 located on the front side thereof are housed, and a select return mechanism and other various accessory mechanisms described later are provided in an intermediate portion. ing.

The transmission 2 has an input shaft 21 connected to an engine output shaft (not shown) via a clutch 3 and a sliding yoke at the end of a propeller shaft (not shown) connected to the rear end of the main shaft 22. It has become so. The input shaft 21 and the main shaft 22 are arranged in a straight line in the front-rear direction and are rotatably coupled to each other via bearings.
Reference numeral 3 is arranged below the main shaft 22 in parallel therewith. And these are the bearings 115, 116,
It is rotatably supported by the transmission case 1 via 121 and 122.

The counter shaft 23 is the input shaft 21.
The drive shaft 210 and the counter drive gear 230 meshing with the drive gear 210 are interlocked with the input shaft 21. On the main shaft 22 and the counter shaft 23, the gears 221 and 231 for the third speed gear train, the gears 222 and 232 for the second speed gear train, and the gears 223 for the first speed gear train.
233, gears 224 and 234 of the reverse gear train, and gears 226 and 236 of the overdrive gear train are arranged. In the gear trains other than the reverse gear, the gears of both shafts 22 and 23 mesh with each other, and the gears 224 and 234 of the reverse gear train are idle gears 271, 272.
Idle gears 271, 272
Are supported by an idle shaft 27 attached to the rear case 12.

The gears 221, 222, 223, 224, 226 arranged on the main shaft 22 are rotatable with respect to the main shaft 22. Further, the main shaft 22 has a synchronizer 24 for the third speed and the fourth speed, and a first speed and the second speed.
A speed synchronizer 25 and an overdrive-reverse synchronizer 26 are provided. Each synchronization device 24-26
Has sleeves 24a, 25a, and 26a that slide in response to the operation of shift rods 41 to 43, which will be described later.
In the case of the fourth speed synchronizer 24, the input shaft 21) is connected to the main shaft 22, and when the sleeve slides to the rear side, the gear behind the synchronizer is connected to the main shaft 22.
When the sleeve is in the neutral position, the gears on the front and rear sides are not connected to the main shaft 22.

A control rod 40 is attached to the upper portion of the transmission case 1, and first, second and third shift rods 41, 42 and 43 are provided.
These constitute a shift system. The control rod 40 is disposed above the tubular portion of the transmission case 1 and has a rear end protruding outside the cone-shaped portion of the rear case 12, and the rear end is connected to a change lever (not shown) via a link. As a result, the control rod 40 rotates and slides in response to the change lever selection or shift operation.

The shift rods 41 to 43 are
The control rods 40 are arranged on one side of the control rod 40 and are slidably supported by the sub-frame 45 in the transmission case 1 in a state of being parallel to each other. The control rod 40 is provided with a select engagement piece 40a while the shift rods 41 to 43 are provided with select gates 41a, 42a and 43a, respectively.
The engaging piece 40a selectively selects the select gates 41a, 42 according to the rotational position of the control rod 40.
It is adapted to engage with one of a and 43a.
The shift rods 41 to 43 are provided with sleeves 24 of the synchronization devices 24 to 26 arranged on the main shaft 22.
shift fork 41b engaging with a, 25a, 26a,
42b and 43b are provided.

A select return mechanism 50 is provided for the shift system such as the control rod 40 to return the shift system to the basic position when in neutral. As shown in FIG. 3, the select return mechanism 50 has piston members 52a and 52b and springs (biasing members) 53a and 53b housed in a pair of select return member housing chambers 51a and 51b, respectively. The piston members 52a and 52b are urged by springs 53a and 53b to apply a restoring force to the members of the shift system, and in this embodiment, the restoring force acts on the control rod 40.

That is, the select return member accommodating chambers 51a and 51b, which open downward, are formed on both sides of the rear case 12 where the control rods are arranged.
The lower end of each of the storage chambers 51a, 51b is
Piston members 52a and 52b projecting downward from 51b
And springs 53a and 53b that bias the piston members 52a and 52b downward, and a lid member 54 is fitted to the upper ends of the accommodating chambers 51a and 51b. On the other hand, the control rod 40 is provided with a pair of claw pieces 55a and 55b, which protrude to both sides, in a row.
5a and 55b are in contact with the lower ends of the piston members 52a and 52b. Then, when the control rod 40 is in the basic position which is the intermediate position of the movable range in the rotation direction, the upper end edge portion 56 of each of the piston members 52a and 52b.
Each piston member 52a, up to the position where the abutting contact with the stepped stopper portion 57 formed on the inner surface of the accommodation chamber 51a, 51b.
52b is in a lowered state.

The piston members 52a, 52b are formed with a communication hole 61 for communicating the inside of the storage chambers 51a, 51b with the space inside the transmission case 1. Further, a passage for communicating at least one of the two accommodation chambers 51a, 51b with the outside air is formed in the rear case, and in this embodiment, a passage 62 for communicating the accommodation chamber 51b on the right side in FIG. 3 is formed.
And a communication passage 6 for communicating the two storage chambers 51a and 51b with each other.
And 3 are formed on the rear case 12. In this way, both the accommodation chambers 51a and 51b are also used as the breather chamber. An outlet member 64 is connected to the end of the passage 62 on the atmosphere side, and a valve that opens to let out air when the pressure in the passage 62 is slightly higher than atmospheric pressure is provided inside the outlet member 64. 65 is provided.

In addition to the select / return mechanism 50, a detent mechanism (not shown) which gives a feeling of motion when the shift rod slides in response to a shift operation of a change lever shifts two or more shift rods simultaneously. The shift system is also provided with an interlock mechanism for surely preventing such a situation, a reverse misshift prevention mechanism for preventing a shift from overdrive to reverse due to an erroneous operation, and the like.

According to the transmission of this embodiment as described above,
With the rotation and sliding of the control rod 40 in response to operations in the change lever select direction and shift direction (not shown), the synchronizer is selectively operated via the shift rods 41 to 43 to perform gear shifting. In the select / return mechanism 50, when the control rod 40 is rotated from the basic position by the operation in the change lever select direction, for example, when the control rod 40 is rotated clockwise in FIG. 3, the left piston member 52a causes the pawl piece 55 to move.
When it is pushed up by a, a restoring force corresponding to it acts, and when it is rotated counterclockwise, the right piston member 52b is pushed up by the claw piece 55b and a restoring force corresponding to it acts. Due to such a restoring force, the control rod 40 is returned to the basic position during neutral.

The accommodating chambers 51a and 51b of the select / return mechanism 50 communicate with the inside of the transmission case 1 through the communication hole 61, and also the passage 62 and the communication passage 63.
A breather function can be obtained by communicating with the atmosphere side via. In other words, when the internal pressure of the transmission case 1 rises, the air inside the transmission is filled with the air in the storage chamber 51.
The air flows between the inside of the transmission case 1 and the outside air side according to the pressure fluctuation in the transmission case 1 due to the temperature change and the like, such as being discharged to the outside air side from the passage 62 via a and 51b. Done. Then, when the air inside the transmission case 1 is discharged, the oil mist mixed in the air is separated in the accommodation chambers 51a and 51b, and the discharge of the oil mist to the outside air side is suppressed.

In particular, the accommodating chambers 51a and 51b have piston members 52a and 52b and springs 53a and 53, respectively.
b, and the communication hole 61 has piston holes 52a, 5
These are the constituent elements of the select return mechanism 50 when they act as air escapes when the 2b moves, and these are utilized to obtain the breather function as described above with a simple structure in which a passage 62 or the like is added to them. Be done.

Further, in this embodiment, both accommodation chambers 51a, 51a
Since b is communicated with each other through the communication passage 63, both the storage chambers 51a and 51b are also used as the breather chamber,
A breather chamber having a large volume can be obtained, and the oil mist separating action and the like can be enhanced.

In the above embodiment, one accommodation chamber 51b of the select return mechanism 50 is communicated with the atmosphere side by the passage 62, and the communication passage 63 is formed between the accommodation chambers 51a and 51b. Both accommodation chambers 51a, 51
b may be individually communicated with the atmosphere side via the passage, or only one of the accommodation chambers may be communicated with the atmosphere side.

[0026]

As described above, according to the present invention, in the transmission having the select return mechanism, the select return member accommodating chamber is communicated with the inside of the transmission case, and
Since a passage for communicating this storage chamber with the atmosphere is formed in the transmission case and this storage chamber is also used as the breather chamber, a breather function can be provided with a simple structure by using a part of the select return mechanism. In addition, it is not necessary to form a breather chamber separately from the select return mechanism, and the transmission can be made compact.

Further, in the present invention, when the communication passage for communicating the pair of select return member accommodating chambers with each other and the passage for communicating one of the accommodating chambers with the atmosphere are provided, the breather chamber has a simple and compact structure. As a result, a large volume can be secured and the effect of removing oil mist can be enhanced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an entire transmission according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the transmission cut in a direction orthogonal to a transmission axial direction at a portion where a select return mechanism is provided.

FIG. 3 is an enlarged cross-sectional view of a part of the portion shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission case 2 Transmission 50 Select return mechanism 51a, 51b Select return member storage chamber 52a, 52b Piston member 53a, 53b Spring 61 Communication hole 62 Passage 63 Passage 63

Claims (2)

[Claims] 1. A piston member and an urging member housed in a member housing chamber for select return, wherein the piston member urged by the urging member returns the shift system to a basic position at the time of neutral. In a transmission having a configured select return mechanism, the select return member accommodating chamber is communicated with the inside of the transmission case, and a passage for communicating the accommodating chamber with the atmosphere is formed in the transmission case to accommodate the accommodating chamber. The breather structure of the transmission that doubles as a breather room. 2. A transmission case is provided with a pair of select return member accommodating chambers, and a communication passage for communicating these chambers with each other and a passage for communicating one chamber with the atmosphere. The breather structure for a transmission according to claim 1.