JP6390687B2 - Breather structure of differential unit - Google Patents

Description

  The present invention relates to a breather structure of a differential unit mounted on a vehicle, and belongs to the field of preventing oil scattering from the breather to the outside.

  A differential unit mounted on a vehicle absorbs a rotation difference between left and right wheels, as is well known, and a differential gear mechanism including a pinion shaft, a pinion gear, and a side gear for absorbing this rotation difference. A differential gear case that houses the differential gear mechanism and that is fitted with a ring gear that meshes with a drive gear connected to a power source; and a differential housing that houses the differential gear case and rotatably supports the differential gear case. Ordinarily, lubricating oil for lubricating the meshing portion of the drive gear and the ring gear, etc., is stored in the lower portion of the inner space of the differential housing by scraping with the ring gear.

  The pressure inside the differential housing may increase due to a rise in the temperature of the lubricating oil accompanying the rotation of the gear. As described above, when the internal pressure of the differential housing becomes high, there is a possibility that the lubricating oil leaks from the seal portion. Therefore, in order to prevent the internal pressure from increasing, a breather device may be provided in the differential housing.

  In Patent Document 1, as a breather device of a differential unit, a breather chamber for separating air and liquid or foam-like lubricating oil into a differential housing, and an air that opens when the internal pressure of the breather chamber increases to a certain level or more. Is provided with a breather plug (a breather union in Patent Document 1) having a function as a valve for letting the air escape to the outside.

  By the way, the lubricating oil in the differential housing may be scraped up by the rotation of the ring gear or the like and scattered to the upper part of the internal space or the like, and depending on the scattering situation, it may enter the breather chamber beyond a certain limit. There is. In this case, inconveniences such as the lubricating oil flowing out through the breather plug will occur.

  Therefore, conventionally, the position and size of the breather chamber and the communication portion between the breather chamber and the internal space of the differential housing are set in consideration of the lubricating oil scattered in the differential housing from leaking outside. ing.

  Specifically, the liquid level of the lubricating oil in the differential housing changes depending on the running state such as acceleration, deceleration, turning state, road surface gradient, etc. of the vehicle, and accordingly, the scraped state by the ring gear or in the differential housing The lubrication state of the breather chamber and the communication part is determined so that the lubrication oil flow-out state from the breather device is evaluated for each condition such as acceleration, and so that it does not flow under any conditions. Etc. are set.

JP2016-128706A

  By the way, the scattering state of the lubricating oil in the differential housing as described above varies depending on the size and position of the ring gear that scoops up the lubricating oil. In other words, even with the same differential unit, if the gear ratio between the drive gear and the ring gear differs depending on the type and specification of the vehicle to be mounted, the size and position of the ring gear and the shape of the differential housing differ. The situation of scraping or scattering of the lubricating oil in the differential housing is different. Therefore, when the breather device is directly provided in the differential housing as in the differential unit described in Patent Document 1, the above-described lubricating oil leakage evaluation test is required for each ring gear specification. It has the problem of increasing.

  Therefore, the present invention performs the above-described evaluation test for each specification of the ring gear, the shape of the differential housing, and the like in a vehicle in which the differential housing is disposed on one side of the engine, for example, a vehicle in which the engine is vertically installed. It is an object of the present invention to provide a breather structure for a differential unit that reduces the necessity and suppresses an increase in development man-hours.

  In order to solve the above-mentioned problem, the breather structure of the differential unit according to the present invention is configured as follows.

According to the first aspect of the present invention, a differential housing is attached to one of the left and right sides of an oil pan provided in an engine, and one of the left and right drive shafts extending from the differential housing in the vehicle width direction is attached to the oil pan. A breather structure of a differential unit that is inserted through the provided through-hole,
On the other side of the oil pan, a drive shaft support bracket is attached that has a through hole that is continuous with the through hole and through which the one drive shaft is inserted.
The drive shaft support bracket is provided with a breather device for communicating the inside of the differential housing with the outside .
A passage is provided between the through hole of the oil pan and the through hole of the drive shaft support bracket, and the drive shaft,
The breather device includes a breather plug having a communication path communicating with the drive shaft support bracket.
The inside of the differential housing communicates with the breather device through the passage .

Invention according to claim 2,
A differential unit in which a differential housing is attached to one of the left and right side surfaces of an oil pan provided in the engine, and one of the left and right drive shafts extending in the vehicle width direction from the differential housing is inserted into a through hole provided in the oil pan. The breather structure of
On the other side of the oil pan, a drive shaft support bracket is attached that has a through hole that is continuous with the through hole and through which the one drive shaft is inserted.
The drive shaft support bracket is provided with a breather device for communicating the inside of the differential housing with the outside .
The breather device is provided at an end on the anti-oil pan side of the drive shaft support bracket .

The invention according to claim 3 is the invention according to claim 1 or 2,
The left and right drive shafts each have a universal joint at a portion protruding outward from the differential housing or the drive shaft bracket,
The drive shaft support bracket is provided so that the universal joints of the left and right drive shafts are arranged at symmetrical positions of the vehicle .

  First, according to the first aspect of the present invention, one drive shaft extending from a differential housing attached to one side surface of an oil pan provided in the engine is provided on the through hole of the oil pan and the other side surface of the oil pan. The drive shaft support bracket is inserted into a through-hole, and the drive shaft support bracket is provided with a breather device, that is, the differential housing and the breather device are provided at positions separated from each other. Therefore, since the lubricating oil scattered in the differential housing is prevented from reaching the breather device provided on the drive shaft support bracket, the leakage state of the lubricating oil has an influence on the ring gear specifications, the shape of the differential housing, etc. It becomes difficult to receive. As a result, the leakage state of the lubricating oil from the breather device is not easily affected by changes in the scattering state of the lubricating oil in the differential housing depending on the traveling state of the vehicle (vehicle speed, turning, gradient, etc.). The number of evaluation tests for each specification can be limited, and the development man-hours can be reduced.

According to the invention described in claim 2, the breather device is provided at the end on the anti-oil pan side of the drive shaft support bracket, so that the arrangement position of the breather device is maximum with respect to the differential housing. As a result, it is possible to further reduce the influence of the lubricating oil scooped up by the ring gear in the differential housing and the scattered lubricating oil depending on the running state of the vehicle. As a result, the number of evaluation tests accompanying the design change of the differential unit can be limited similarly to the first aspect, and the development man-hour can be reduced.

Further, according to the invention described in claim 3, the drive shaft support bracket is provided so that the universal joints of the left and right drive shafts are arranged at symmetrical positions of the vehicle. Can be long. That is, the bending angles of the left and right drive shafts are the same, the torque transmission efficiency is equalized between the left and right wheels, and the rotation difference between the left and right wheels can be suppressed. In addition, when the function of the breather is added to the drive shaft support bracket having a good support function of the drive shaft and a function of suppressing the occurrence of the rotation difference of the wheel, the breather device is provided separately from the differential housing. Increase in the number of parts is suppressed.

1 is a schematic plan view of a vehicle according to an embodiment of the present invention. It is a perspective view of the differential unit which concerns on embodiment of this invention. It is a cross-sectional enlarged view of the differential apparatus in FIG. It is sectional drawing of the AA line of FIG. It is sectional drawing of the principal part in FIG.

  Hereinafter, an embodiment of a breather structure in a differential unit according to the present invention will be described.

  First, the configuration of the vehicle 1 to which the differential unit according to the embodiment is applied will be described with reference to FIG. This vehicle 1 is a so-called vertical engine type in which the axial direction of the engine 2 is the longitudinal direction of the vehicle, and a four-wheel drive vehicle in which a pair of left and right front wheels 11L and 11R and rear wheels 12L and 12R are drive wheels, respectively. A transmission 3 is arranged behind the engine 2 and a transfer device 4 that distributes torque output from the transmission 3 to the front and rear wheels 11L, 11R, 12L, and 12R is connected.

  A rear differential device 6 is connected to the rear portion of the transfer device 4 and distributes the torque input by the propeller shaft 5 to the left and right rear wheels 12L and 12R at the rear end of the first propeller shaft 5 extending rearward of the vehicle. Is connected. Further, the torque input to the propeller shaft 7 is transmitted to the front end of the second propeller shaft 7 connected to the side portion of the transfer device 4 and extending forward of the vehicle body via the left drive shaft 13 and the right drive shaft 14. A front differential device 8 is connected to each of the pair of left and right front wheels 11L and 11R.

  The front differential device 8 has a differential housing (hereinafter referred to as “differential housing”) 81. As shown in FIG. 2, the differential housing 81 is provided on the left side of the oil pan 21 of the engine 2 in this embodiment. A drive shaft support bracket 82 for obtaining good support of the right drive shaft 14 is fixed to the side surface of the oil pan 21 on the side opposite to the differential housing by bolts 82a... 81a. ing.

  Next, the front differential device 8 will be described with reference to FIG. The differential device 8 is housed in the differential housing 81 and includes a differential gear case (hereinafter referred to as “differential case”) 84 that houses a differential gear mechanism 83 therein, and a ring gear 85 that is assembled to the differential case 84. The differential case 84 is provided with cylindrical boss portions 86 and 87 extending left and right at both ends in the axial direction of the differential case 84, and the left and right drive shafts 13 and 14 are respectively disposed on inner peripheries of the boss portions 86 and 87. Penetrated and supported. The differential case 84 is rotatably supported by the differential housing 81 via bearings 86a and 87a provided on the outer periphery of the boss portions 86 and 87.

  The differential gear mechanism 83 housed in the differential case 84 includes a pinion shaft 83a, a pinion gear 83b, and a side gear 83c. The pinion shaft 83a is provided at the center of the differential case 84 so as to be orthogonal to the axial direction of the drive shaft. A pair of pinion gears 83b and 83b are rotatably fitted to both ends of the pinion shaft 83a. And a pair of side gears 83c and 83c that mesh with the pair of pinion gears 83b and 83b. The left and right drive shafts supported by the boss portions 86 and 87 of the differential case 84 are supported by the side gears 83c and 83c. The end portions of 13 and 14 are spline-fitted.

  A left front wheel 11L is connected to the tip of the left drive shaft 13 on the side opposite to the differential device, and a portion of the left drive shaft 13 protruding from the differential housing 81 to the outside is sealed by an oil seal 13a.

  On the other hand, as shown in FIG. 4, the right drive shaft 14 is provided in the drive shaft support bracket 82 so as to be continuous with the through hole 21a provided in the oil pan 21 below the engine 2 and the through hole 21a. The right front wheel 11R is connected to the tip of the right drive shaft 14 on the side opposite to the oil pan. The right drive shaft 14 is supported by the drive shaft support bracket 82 via a bearing 87b, and a portion protruding to the outside from the drive shaft support bracket 82 is sealed by an oil seal 14a.

  Here, the configuration of the through holes 21a and 82b through which the right drive shaft 14 penetrates will be described in detail.

  As shown in FIG. 4, the oil pan 21 is provided with a cylindrical portion 21 b between the left and right side surfaces of the oil pan 21, and the inside of the oil pan 21 is a through hole 21 a that penetrates the oil pan 21 left and right. ing. Further, the drive shaft support bracket 82 is also formed in a cylindrical shape, and the inside thereof is a through hole 82b extending in the vehicle left-right direction. The through holes 21a of the oil pan 21 and the through holes 82b of the drive shaft support bracket 82 are directly connected, and the right drive shaft 14 is inserted into the through holes 21a and 82b. The inner diameters of the through holes 21a and 82b are set to be larger than the outer diameter of the right drive shaft 14, and the right drive shaft 14 is inserted with a gap between the through holes 21a and 82b. Yes.

  Further, a breather device 90 for preventing an increase in the internal pressure of the differential housing 81 protrudes from the upper end of the drive shaft support bracket 82 on the side opposite to the oil pan.

  Here, the breather device 90 will be described with reference to FIG. The cylindrical breather plug 91 has a communication passage 91a communicating with the inside of the drive shaft support bracket 82 inside, and one end side of the breather plug 91 is on the upper surface of the end of the drive shaft support bracket 82 on the side opposite to the oil pan. For example, it is press-fitted or screwed into the boss portion 82c provided. A breather plug 91 attached to the boss portion 82c, a disc-like valve body 92 disposed on the other end side of the breather plug 91 so as to close the communication passage 91a, and a valve body 92 disposed above the valve body 92. A spring 93 and a cap 94 disposed so as to cover the spring 93 and restricting the bias of the spring 93 are provided. The cap 94 is press-fitted into the breather plug 91, and has an air vent hole 94a on its upper surface.

  In the breather device 90 configured as described above, when the internal pressure of the differential housing 81 rises, the air in the drive shaft support bracket 82 pushes up the valve body 92, and between the upper end portion of the breather plug 91 and the valve body 92. By passing through the gap between the breather plug 91 and the cap 94 from the gap and through the hole 94a provided on the upper surface of the cap 94, the internal pressure of the differential housing 81 is adjusted. Yes. In place of the air vent hole 94a provided on the upper surface of the cap 94, a gap is provided between the outer peripheral portion of the breather plug 91 and the inner peripheral portion of the cap 94 corresponding thereto. You may make it pull out.

  By the way, the internal space X of the differential housing 81 is connected to the breather device via the bearing 87a and the clearance between the through hole 21a of the oil pan 21 and the through hole 82b of the drive shaft support bracket 82 and the right drive shaft 14. The internal space X and the passage a to the mounting portion of the breather device 90 are sealed with respect to the external space by seal members 81b and 82d. As shown in FIG. 4, the oil pan 21 and the differential housing 81 are sealed via a seal member 81b, and the drive shaft support bracket 82 and the oil pan 21 are sealed via a seal member 82d. ing.

  And in this embodiment, as shown in FIG. 3, the guide member 88 attached integrally to the sealing member 81b is provided. The guide member 88 includes an outer peripheral portion 88a that faces the side surface of the oil pan 21, and a conical surface portion 88b that rises toward the differential case 84 from an end portion on the right drive shaft 14 side of the outer peripheral portion 88a. The right drive shaft 14 passes through the drive shaft support bracket 82 and the oil pan 21, and is guided so that it can be smoothly fitted to the side gear 83c. The guide member 88 has a gap Y between the tip of the conical surface portion 88b and the differential case 84 and the right drive shaft 14 so as not to block the passage a.

  Further, the differential unit 80 according to this embodiment includes the differential device 8, the differential housing 81, the drive shaft support bracket 82, the breather device 90, the left and right drive shafts 13, 14 and the like. Has been.

  Next, the operation of the breather structure of the differential unit 80 will be described.

  With the above configuration, in the vehicle 1 to which the differential unit 80 is applied, first, the power output from the engine 2 via the transmission 3 when the vehicle travels is transferred from the transfer device 4 via the rear differential device 6. Power transmitted to the rear wheels 12L and 12R and input to the second propeller shaft 7 is a drive gear (not shown), a ring gear 85, a differential case 84, a differential gear mechanism 83, left and right drive shafts 13, 14 to the front wheels 11L and 11R.

  In the front differential device 8, the internal space X of the differential housing 81 includes the gap Y, the through hole 21 a of the oil pan 21, the through hole 82 b of the drive shaft support bracket 82, and the right drive shaft 14. Since the air passes through the passage a formed by the gap between the breather device 90 provided in the drive shaft support bracket 82, when the internal pressure in the internal space X rises due to an increase in the lubricating oil temperature or the like, The valve body 92 of the breather device 90 is opened by the internal pressure, and air is released to the outside. Thereby, an increase in the internal pressure of the internal space X is suppressed, and for example, leakage of lubricating oil from the oil seals 13a and 14a and the seal members 81b and 82d is prevented.

  On the other hand, in the inner space X of the differential housing 81, the ring gear 85 rotates, and the lubricating oil stored in the lower portion of the inner space X is scraped up to the upper portion of the inner space X and scattered around. Become. In this case, according to the present embodiment, the breather device 90 is not provided in the differential housing 81 and is provided at the end on the anti-oil pan side of the drive shaft support bracket 82 that is located away from the differential housing 81. Therefore, the lubricating oil that is scraped up and scattered by the ring gear 85 is prevented from reaching the breather device 90. This can suppress the outflow of the lubricating oil from the breather device 90, and in particular, the influence of the scattering state that changes depending on the state of the liquid surface in the differential housing 81 according to the traveling state (acceleration / deceleration, turning, road surface gradient, etc.). It becomes difficult to receive.

  Therefore, according to changes in specifications such as the position and size of the ring gear 85 and the shape of the differential housing 81, the scattering state of the lubricating oil in the differential housing 81 in the running state (acceleration / deceleration, turning, road gradient, etc.) Even in the case of a change, the outflow situation of the lubricating oil from the breather device 90 does not change, and it is not necessary to perform an evaluation test of the outflow situation of the lubricating oil in accordance with each traveling state of the vehicle 1 every time the specification etc. is changed, This makes it possible to reduce development man-hours.

  Furthermore, since the breather device 90 is provided at the end on the side opposite to the oil pan of the drive shaft support bracket 82 that is located farthest from the differential housing 81, the differential housing according to the running state of the vehicle 1 is provided. It is possible to further reduce the influence of the scattering state of the lubricating oil in 81 and the effect of the lubricating oil scooping up by the ring gear 85.

  In this embodiment, as shown in FIG. 1, the left and right drive shafts 13 and 14 have wheel side drive shafts 13 ′ and 14 ′ and differential device side drive shafts 13 ″ and 14 ″, respectively. The left and right universal joints 13b and 14b are provided at left and right symmetrical positions of the vehicle 1 so that the wheel side drive shafts 13 'and 14' of the left and right drive shafts 13 and 14 have the same length. In order to effectively support the universal joint 14b, the end position of the drive shaft support bracket 82 on the side opposite to the oil pan is set.

  That is, the bending angles of the left and right drive shafts 13 and 14 are the same, the torque transmission efficiency is equalized between the left and right wheels 11L and 11R, and the rotational difference between the left and right wheels 11L and 11R can be suppressed. Further, the breather function is added to the drive shaft support bracket 82 having a good supportability of the left and right drive shafts 13 and 14 and a function of suppressing the rotation difference between the left and right wheels 11L and 11R. An increase in the number of parts when the device 90 is provided separately from the differential housing 81 is suppressed.

  The present invention can be suitably used in a breather structure provided in a differential unit for a vehicle.

1 Vehicle 2 Engine 8 Front differential device (differential device)
13 left drive shaft 13b universal joint 14 right drive shaft 14b universal joint 21 oil pan 21a through hole 80 differential unit 81 differential housing 82 drive shaft support bracket 82b through hole 90 breather device 91 breather plug 91a communication path 92 valve body 93 spring 94 cap 94a Hole a Passage X Internal space Y Clearance

Claims (3)

A differential unit in which a differential housing is attached to one of the left and right side surfaces of an oil pan provided in the engine, and one of the left and right drive shafts extending in the vehicle width direction from the differential housing is inserted into a through hole provided in the oil pan. The breather structure of
On the other side of the oil pan, a drive shaft support bracket is attached that has a through hole that is continuous with the through hole and through which the one drive shaft is inserted.
The drive shaft support bracket is provided with a breather device for communicating the inside of the differential housing with the outside .
A passage is provided between the through hole of the oil pan and the through hole of the drive shaft support bracket, and the drive shaft,
The breather device includes a breather plug having a communication path communicating with the drive shaft support bracket.
A breather structure for a differential unit , wherein the interior of the differential housing communicates with the breather device via the passage . A differential unit in which a differential housing is attached to one of the left and right sides of an oil pan provided in the engine, and one of the left and right drive shafts extending from the differential housing in the vehicle width direction is inserted into a through hole provided in the oil pan. The breather structure of
On the other side of the oil pan, a drive shaft support bracket is attached that has a through hole that is continuous with the through hole and through which the one drive shaft is inserted.
The drive shaft support bracket is provided with a breather device for communicating the inside of the differential housing with the outside .
A breather structure for a differential unit, wherein the breather device is provided at an end of the drive shaft support bracket on the side opposite to the oil pan . The left and right drive shafts each have a universal joint at a portion protruding outward from the differential housing or the drive shaft bracket,
3. The breather structure for a differential unit according to claim 1, wherein the drive shaft support bracket is provided so that the universal joints of the left and right drive shafts are arranged at symmetrical positions of the vehicle. .

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