JP2542423B2 - Power transmission switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is arranged in front of a gear mechanism in a power transmission path for transmitting a driving force from a propulsion shaft to a differential between left and right wheels via a gear mechanism. In particular, the present invention relates to a power transmission switching device, and particularly relates to an air bleeding measure when an electromagnetic actuator for switching between two-wheel drive and four-wheel drive is installed in a closed chamber.

[Prior Art] In the Japanese Patent Application No. 62-162620, the applicant of the present invention discloses a power transmission path for transmitting a driving force from a propulsion shaft to a differential between left and right wheels via a gear mechanism. Disclosed is a four-wheel drive vehicle in which a dog clutch type power transmission switching device is arranged and which is operated by switching between two-wheel drive and four-wheel drive by an electromagnetic actuator. The differential device, the gear mechanism, and the power transmission switching device described above are housed in the housing, but conventionally, the electromagnetic actuator was exposed to the outside of the housing.

[Problems to be Solved by the Invention] By the way, when the electromagnetic actuator is also housed in the housing in order to avoid adverse effects due to external exposure, the electromagnetic actuator is installed in a closed chamber in consideration of insulation failure due to lubricating oil in the housing. There is a need to. However, the electromagnetic actuator has a movable part that moves forward and backward, and there is a problem that the air in the sealed chamber becomes an operating resistance when the movable part moves forward and backward.

On the other hand, although lubricating oil is contained in the housing, since the types of lubricating oil on the differential and gear mechanism sides and on the power transmission switching device side are different, separate them so that they do not mix. It is necessary to provide the seal member of.

Therefore, an object of the present invention is to open the sealed chamber of the electromagnetic actuator to the atmosphere by utilizing the air chamber formed between the both seal members, and reduce the air resistance when the actuator moving part moves forward and backward. Another object of the present invention is to provide a power transmission switching device capable of preventing foreign matter such as dust from entering the actuator side.

[Means for Solving the Problems] In order to achieve the above objects, the present invention provides a power transmission path for transmitting a driving force from a propulsion shaft 73 to a differential 80 between left and right wheels via a gear 75, 76 mechanism. In the power transmission switching device 10 which is disposed in front of the gears 75, 76 mechanism in the above and switches between two-wheel drive and four-wheel drive by the operation of the electromagnetic actuator 41, the differential device 80 and the gears 75, 76 mechanism and the power transmission switching device 1
An electromagnetic actuator 41 is installed in a sealed chamber provided in a housing 50 that accommodates 0, and a differential gear 80 and gears 75, 76 have a lubricating oil seal member 5 on the mechanism side in the housing 50.
6 and lubricating oil seal member 55 on the power transmission switching device 10 side
Is provided to form an air chamber 57 between the seal members 55 and 56, and the electromagnetic actuator 41 is provided through the air chamber 57.
The air vent passages 58 and 59 for opening the closed chamber of (1) to the atmosphere are formed in the housing 50.

[Operation] The housing 50 has an air chamber 57 between the seal members 55 and 56.
Since the air vent passages 58 and 59 that open the closed chamber of the electromagnetic actuator 41 to the atmosphere via the actuator are formed, when the actuator movable portion 44 moves forward and backward,
Air is vented from the chamber to the atmosphere through the passage 58, the air chamber 57, and the passage 59, so that the air resistance can be reduced.

Then, compared with the one in which the actuator 41 chamber is directly opened to the atmosphere, the chamber volume in which the air volume change due to the advancing / retreating operation of the actuator movable portion 44 becomes a large volume by adding the air chamber 57 between both seal members 55, 56, and as a whole. The air resistance becomes very small because the rate of change in the volume of air enclosed in the room volume can be extremely small.

Further, since the actuator 41 chamber is opened to the atmosphere through the passage 58, the air chamber 57, and the passage 59, foreign matter such as dust can be prevented from entering the actuator 41 chamber side.

[Example] An example will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is an input shaft, 6 is an output shaft, 10 is a dog clutch, and a dog clutch 10 is a dog clutch hub.
11, a regulation ball 17, a sleeve 18, a dog piece 31, an electromagnetic actuator (hereinafter referred to as a solenoid) 41, and the like.

The front portion of the output shaft 6 is rotatably assembled through the bearing 7 in the rear portion of the input shaft 1 in which the flange 2 is fixed by the nut 3, and the dog clutch hub 11 is fitted on the input shaft 1 by spline 12 fitting. The dog clutch hub 11 is assembled so as to be slidable in the direction, and has dog teeth 13 at the rear portion. Further, three holes 14 and 15 are formed in the front and rear of the front portion of the dog clutch hub 11 at equal intervals in the circumferential direction, a guide ball 16 is held in the front hole 14, and a regulation ball 17 is held in the rear hole 15. Can be held. The sleeve 18, which is in sliding contact with the balls 16 and 17 from the outer peripheral side, includes an annular protrusion 19 on the inner periphery, and a shift fork 21 is engaged with the sleeve 18,
The shift fork 21 is connected to the shift rod 23 by a pin 22. Reference numeral 24 is a return spring that biases the shift fork 21 rearward.

On the other hand, the dog piece 31 is composed of two members, an outer piece 32 and an inner piece 36, and a dog tooth 33 that meshes with the dog tooth 13 is provided on the front portion of the outer piece 32. The outer piece 32 is installed on the inner piece 36 via a spline 34 fitting in the circumferential direction and a torsion damper 35, and the inner piece 36 is fitted on the output shaft 6 by serration 37 fitting and a nut 8. It is fixed to.

Here, both dog teeth 13, 33 are set in a tapered shape that generates thrust force in the meshed state.

The solenoid 41 for operating the sleeve 18 includes an armature 42, a harness 43, and a movable portion (hereinafter referred to as a push pin) 44, and the push pin 44 is in contact with the rear end of the shift rod 23.

In the above, the housing 50 is composed of the differential carrier 51 and the clutch case 61, and the bearing is provided in the differential carrier 51.
The output shaft 6 through the springs 52, 53 and the spring 54 therebetween.
Is rotatably installed and the oil seal member is in front of it.
55 and 56 are interposed, and a space chamber 57 is formed between the seal members 55 and 56. Further, the solenoid 41 is arranged in parallel below the output shaft 6, and a harness cap 45 and a seal leak detecting bolt 46 are provided on the lower surface of the differential carrier 51 below the solenoid 41.

The input shaft 1 is rotatably mounted in a clutch case 61, which is bolted from the front to the differential carrier 51 with a spacer member 60 interposed therebetween, via a front bearing 62 and an oil seal member 63. Further, the shift rod 23 is arranged in parallel below the input shaft 1, and
23 is guided by the front wall of the clutch case 61 and is also guided by the spacer member 60 via the oil seal member 64.

Further, on the lower surface of the clutch case 61 below the shift rod 23, there is provided a manual operating element 25 having a bolt head 26 for engaging the shift fork 21 with the projection 27, and a stopper for locking the operating element 25. 28 is fastened with bolts 29 (see Fig. 2). In addition, cushioning rubbers 47 and 49 are provided in front of and behind the solenoid 41.

The dog clutch 10 described above is installed in the four-wheel drive vehicle shown in FIG. 4. For example, a propulsion shaft 73 that branches from an engine 71 to a front wheel differential device (gear type differential) 72 and transmits a driving force.
Are connected to the input shaft 1 by flange coupling, and a differential (viscous fluid coupling) 80 for a rear wheel is provided in the differential carrier 51. The driving force is transmitted from the output shaft 6 to the differential device 80 through the hypoid gears 75 and 76.

In this four-wheel drive vehicle, for example, when a four-wheel anti-lock brake device is attached, the dog clutch 10, which is a power transmission switching device, is always kept connected as shown in FIG. 1 to drive the front and rear wheels together. However, when the solenoid 41 is energized in conjunction with the four-wheel anti-lock brake operation,
The dog clutch 10 is disengaged, and only the front wheels are driven. During the switching operation, the push pin 44 of the solenoid 41
The protrusion causes the sleeve 18 to move forward on the dog clutch hub 11 via the shift rod 23 and the shift fork 21. At this time, the fixed dog piece 31 and dog clutch hub 11
A thrust force is generated by the engagement of the tapered dog teeth 13 and 33 between the and, so the engagement of both dog teeth 13 and 33 is promptly released, and the thrust force moves the dog clutch bab 11 forward. To do. As a result, the fitting of the regulation ball 17 into the hole 4 of the input shaft 1 is released.

In this way, the input / output shafts 1 and 6 can be shut off during power transmission with a low operating force for moving the sleeve 18.

When rejoining, the shift fork 21 is deenergized by the energization of the return spring 24 by shutting off the solenoid 41.
The sleeve 18 moves rearward on the dog clutch hub 11 via the, and the regulation ball 17 is fitted and held again in the hole 4 of the input shaft 1 by the sleeve annular projection 19 and both dog teeth 1 are rotated by the tolerance rotation.
3,33 re-engagements are made. At this time, the function of the torsion damper 35 with the spline 34 fitting portion having a circumferential gap provided between the outer piece 32 and the inner piece 36 constituting the dog piece 31 reduces shock at the time of reconnection. .

In the above, the inside of the differential carrier 51 and the clutch case 61
Different kinds of lubricating oil are put in the inside. In other words, four-wheel drive is always performed, so the differential carrier 51
Lubricating oil similar to, for example, mission oil for hypoid gears 75 and 76 that constantly rotate from the output shaft 6 to the differential device 80 is adopted in the clutch case 61, but a dog that moves only during switching operation is used in the clutch case 61. Teeth 13,33 and shift rod 23
A lubricating oil such as grease for the splines 12 and 34 is used.

The two oil chambers are partitioned by the seal members 55 and 56, and an annular space chamber 57 as shown in FIG. 3 is formed between the back surfaces of the seal members 55 and 56. This space room
A solenoid 41 is installed in a closed chamber provided diagonally below 57, and radial passages 48 are formed on the front and rear faces of a thick annular rubber 47 for cushioning interposed between the front surface of the solenoid 41 and the spacer member 60. Has been done. Here, both the seal members 55, 56 and the other seal members 63, 64 are made of a seal rubber a,
It is composed of a metal plate b for maintaining the outer diameter holding force by press-fitting the seal rubber a, and a spring c for urging the inner diameter of the seal rubber a in the diameter reducing direction.

Further, an air vent passage 58 communicating with the solenoid 41 chamber side and an air vent passage 59 opening to the atmosphere are formed in the space chamber 57. That is, as shown in FIG.
And the solenoid 41 chamber are connected at the shortest distance to communicate with the passage 48 of the cushioning gum 47, and the air vent passage 59 opens downward from the air chamber 57.

In the switching operation between the two-wheel drive and the four-wheel drive, when the push pin 44 of the solenoid 41 moves forward and backward as shown by the broken line in FIG. 1, the shift rod 23 also moves back and forth,
A change in the air volume inside the thick annular rubber 47 occurs within the range of the chain line. This air volume change is due to the rubber passage 48 and the air vent passage 5
8. The movement of air between the air chamber 57 and the atmosphere passing through the air vent passage 59, that is, the respiration action is compensated.

Since the air vent passage 59 is opened downward from the air chamber 57, it is excellent in discharging dust and muddy water that have entered the air chamber 57, and the air vent passage 58 of the space chamber 57 and the solenoid 41 space is connected to the atmosphere opening passage. It is also excellent in terms of preventing foreign matter from entering the solenoid 41 chamber due to the labyrinth action, because the direction is different from that of 59.

Further, as shown by the dotted line in FIG. 3, if the air vent passage 58 for the space chamber 57 and the solenoid 41 space is provided at a high position in the upper part, it becomes more convenient in terms of preventing foreign matter from entering the solenoid 41 chamber. .

By the way, when the space chamber 57 between the back surfaces of both the seal members 55, 56 is sealed, if a negative pressure is generated in the sealed space chamber 57 due to temperature changes of the front and rear oil chambers, the sealing performance of the seal members 55, 56 However, this is eliminated by providing the space chamber 57 with the passage 59 for opening to the atmosphere. Further, if oil leaks from the passage 59, it can be detected that the seal members 55 and 56 have a poor seal.

If the bolt 46 on the lower surface of the differential carrier 51 below the solenoid 41 is removed and there is an oil leak, a sealing failure of the seal member 64 can be detected.

Although the power transmission switching device provided on the rear wheel differential device side is used in the embodiment, it may be provided on the front wheel differential device side, and the specific structure of the switching device is not limited to the dog clutch. Instead, any one can be adopted.

[Advantages of the Invention] As described above, according to the present invention, since the air vent passage that opens the airtight chamber of the electromagnetic actuator to the atmosphere through the air chamber between the seal members is formed in the housing, the movable portion of the actuator moves forward and backward. In doing so, the operating resistance can be reduced by venting air from the actuator chamber to the atmosphere through the air chamber between the seal members.

Moreover, compared with the one in which the actuator chamber is directly opened to the atmosphere, the chamber volume in which the air volume changes due to the advancing / retreating operation of the actuator moving part becomes a large volume by adding the air chamber between both seal members, and the air volume to be closed to the overall chamber volume is increased. Since the rate of volume change can be made extremely small, the air resistance becomes very small.

Since the actuator chamber is opened to the atmosphere via the air chamber between the seal members, it is also excellent in preventing foreign matter such as dust from entering the actuator chamber side.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of a power transmission switching device portion to which the structure of the present invention is applied, FIG. 2 is a partial bottom view from the direction of arrow II in FIG. 1, and FIG. 3 is an essential part for explaining the air bleeding action. FIG. 4 is a schematic configuration diagram of a four-wheel drive vehicle. In the drawing, 10 is a power transmission switching device, 13 and 33 are dog teeth, 2
3 is a shift rod, 41 is an electromagnetic actuator, 44 is a movable part, 50 is a housing, 55 and 56 are seal members, 57 is an air chamber, 58 and 59 are air vent passages, 73 is a propulsion shaft, 75 and 76 are gears,
80 is a differential device.

Claims (1)

(57) [Claims] 1. A two-wheel drive and four-wheel drive system, which is arranged in front of a gear mechanism in a power transmission path for transmitting a driving force from a propulsion shaft to a differential device between right and left wheels via a gear mechanism, by operating an electromagnetic actuator. In a power transmission switching device that switches to drive, an electromagnetic actuator is installed in a closed chamber provided in the housing that houses the differential gear and gear mechanism and the power transmission switching device. The lubricating oil seal member and the power transmission switching device side lubricating oil seal member are provided to form an air chamber between the two sealing members, and the airtight chamber of the electromagnetic actuator is opened to the atmosphere through the air chamber. A power transmission switching device characterized in that an air vent passage is formed in the housing.