JP2008128265A - Differential case provided with lubricating oil holding lip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase an amount of the lubricating oil which is held inside the differential case, under the assumption of the lubricating oil supply structure in which the supply of the lubricating oil into the differential case inside is conducted by gravity through an opening provided in the side wall portion of the differential case to introduce side gear and a pinion into the differential case inside. <P>SOLUTION: Inward facing lubricating oil holding lips are installed on the brim of the opening. The lubricating oil holding lips are performed by a fixed type or may preferably be slanted in the closing direction in accordance with the increase of revolving speed of the differential case or the temperature increase of the differential case. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a differential device incorporated in a drive system of a vehicle such as an automobile, and more particularly to a differential case (commonly referred to as a differential case) constituting a part of the differential device.

  A differential device incorporated in a drive system of a vehicle such as an automobile supports a pair of opposed side gears and at least a pair of pinions engaged therebetween so as to be rotatable around respective central axes, and the central axes of the pair of side gears And a differential case for rotating the pair of side gears around the central axis while allowing differential rotation between the pair of side gears. The pair of side gears drive a pair of left and right drive wheels. In this case, as long as the pair of drive wheels are driven at the same angular velocity, the side gear and the pinion rotate together around the central axis of the side gear, and no relative rotation occurs between the side gear and the pinion. When a difference in angular velocity occurs between the pair of side gears and a difference occurs between the two side gears, meshing rotation occurs between the side gears and the pinion. Therefore, lubricating oil that lubricates the meshing part between the side gears and the pinion is used. It must be kept inside the differential case.

Patent Document 1 below describes that a lubricating oil reflecting portion that reflects the flow of the lubricating oil and easily enters the opening is provided at the inlet portion of the opening through which the lubricating oil flowing outside the differential case is introduced into the differential case. ing. Japanese Patent Application Laid-Open No. H10-228561 describes that a recess that acts as an oil reservoir for holding lubricating oil is provided in the meshing portion of the side gear and the pinion during rotation of the differential case. Further, in Patent Document 3 below, a notch groove is formed in a plurality of lubricating oil inlets provided on the outer peripheral wall of the differential case so as to be gradually shallower toward the rear with respect to the rotational direction of the differential case, and the differential is provided there. It is described that a guide valve is provided that opens in a direction in which the lubricating oil is scraped by a centrifugal force generated by rotation of the case.
JP-A-8-320057 JP 2000-174327 A JP 7-19659 A

  The side wall of the differential case is provided with an opening for inserting the side gear and pinion into the differential case, so that if the lubricating oil is properly dropped onto the differential case from the top of the differential housing, the differential case When the opening is turned upward with the rotation of the oil, the lubricating oil flows into the differential case through the opening, and the meshing portion of the side gear and the pinion incorporated in the differential case can be lubricated. However, since the differential case rotates, there is a time zone in which the opening is downward as well as a time zone in which the opening is upward, and from the inside of the differential case passing through the opening while the opening is downward. Lubricant spill occurs. Further, when the differential case rotates, the lubricating oil also flows out from the differential case passing through the opening due to centrifugal force. Therefore, conventionally, the amount of lubricating oil retained in the differential case by such a lubricating structure has been limited.

  According to the present invention, the lubricating oil is supplied into the differential case by gravity through an opening provided in a side wall portion of the differential case in order to insert the side gear and the pinion into the differential case. On the premise of the supply structure, an object is to increase the amount of lubricating oil retained in the differential case.

  In order to solve the above-mentioned problems, the present invention supports a pair of opposing side gears and at least a pair of pinions meshing therebetween so as to be rotatable around their respective central axes, and matches the central axes of the pair of side gears. A differential case that is rotatably supported around a central axis, and that rotates the pair of side gears around the central axis while allowing differential rotation between the pair of side gears, and for inserting the side gear and the pinion The differential case is characterized by having an inward lubricating oil retaining lip at the edge of the opening.

  The lubricating oil holding lip may be a fixed lip formed integrally with the differential case, but the lubricating oil holding lip is deflected in the direction of narrowing the opening by a centrifugal force acting with the rotation of the differential case. It may be. In this case, the deflection in the direction of narrowing the opening of the lubricating oil retaining lip may be increased with an increase in the rotational speed of the differential case, and the lubrication increasing with an increase in the rotational speed of the differential case. The deflection in the direction of narrowing the opening of the oil retaining lip may be determined by the balance between the centrifugal force acting on the lubricating oil retaining lip and the spring force against it as the differential case rotates.

  Alternatively, the lubricating oil retaining lip may be deflected in the direction of narrowing the opening due to an increase in the temperature of the differential case. In this case, the deflection in the direction of narrowing the opening of the lubricating oil retaining lip due to an increase in the temperature of the differential case may be performed by a bimetal that is sensitive to the temperature of the differential case.

  As described above, a pair of opposed side gears and at least a pair of pinions engaged therebetween are supported rotatably about their respective central axes, and can be rotated about a central axis that coincides with the central axes of the pair of side gears. In a differential case that is supported and rotates the pair of side gears around their central axis while allowing differential rotation therebetween, the edges of the openings for inserting the side gears and the pinions are inward If the lubricating oil retaining lip is provided, when the opening is directed upward as the differential case rotates, the lubricating oil dripping from above onto the differential case flows into the differential case through the opening. Without obstructing, when the opening is facing downward, lubricating oil passes through the opening and Fan Ren better prevented from flowing out from within the interstitial case, it is possible to increase the amount of lubricating oil held in the differential case than in the absence of such lubricant retaining lip.

  The lubricating oil retaining lip as described above does not interfere with the flow of the lubricating oil into the differential case from the opening, and the effect of promoting the inflow of the lubricating oil into the differential case through the opening. Therefore, the presence or absence of the lubricating oil retaining lip does not affect the amount of lubricating oil flowing into the differential case through the opening corresponding to the rotational speed of the differential case. On the other hand, the outflow of the lubricating oil from the differential case through the opening is affected by the centrifugal force acting on the lubricating oil in the differential case as the differential case rotates, and the outflow of the lubricating oil from the differential case is The amount of lubricating oil to be retained in the differential case increases as the rotational speed of the differential case increases. However, as the rotational speed of the differential case increases, the meshing portion between the side gear and the pinion increases. In order to be well lubricated, it is considered preferable that the amount of lubricating oil retained in the differential case is increased as the rotational speed of the differential case increases.

  Therefore, if the lubricating oil retaining lip is deflected in the direction of narrowing the opening by the centrifugal force acting with the rotation of the differential case, the differential through the opening as the rotational speed of the differential case increases. The outflow of the lubricating oil from the inside of the case can be further suppressed, and the amount of the lubricating oil retained in the differential case can be increased accordingly. If the lubricating oil retaining lip provided inwardly on the edge of the opening is deflected in the direction of narrowing the opening, the lubricating oil is retained against the fact that the lubricating oil tends to flow out of the differential case through the opening. Since a larger lubricating oil holding space is formed, the outflow of lubricating oil from the differential case is better suppressed. Regarding the inflow of the lubricating oil into the differential case through the opening, even if the lubricating oil that has passed through the opening entrance collides with the lubricating oil holding lip deflected in the direction of narrowing the opening, the lubricating oil Since it flows along the holding lip and flows into the differential case, the fact that the lubricating oil holding lip is deflected in the direction of narrowing the opening does not hinder the inflow of the lubricating oil into the differential case, and from the inside of the differential case. The effect of suppressing only the outflow of lubricating oil is produced.

  Further, it is preferable that the amount of the lubricating oil supplied to the meshing portion of the sight gear and the pinion is increased as the temperature of these portions increases. In this regard, if the lubricating oil retaining lip is deflected in a direction that narrows the opening due to an increase in the temperature of the differential case, the lubricating oil retaining lip is opened according to the increase in the temperature of the differential case. Since the amount of lubricant retained in the differential case can be increased as described above, the amount of lubricant retained in the differential case increases as the temperature of the differential case increases. The amount of lubricating oil supplied to the meshing part of the pinion can be increased.

  FIG. 1 is an exploded view in longitudinal section showing an example of a differential gear incorporating one embodiment of a differential case according to the present invention. In FIG. 1, reference numeral 10 denotes a differential case, which supports a pair of opposed side gears 12L, 12R and at least a pair of pinions 14, 16 engaged therebetween so as to be rotatable around respective central axes. It is supported by the differential housing 18 so as to be rotatable around a central axis Cd that coincides with the central axis of the pair of side gears, and a bolt 10f is provided at a portion of the flange portion 10f, only a part of which is shown in the figure. An input gear 22 which is attached by 20 and only a part of which is shown in the drawing is driven by a driving gear not shown in the drawing to be driven to rotate around the central axis Cd. .

  More specifically, the pair of side gears 12L, 12R is supported by the inner ends of the left and right axles 24L, 24R, and the differential case 10 that supports the side gears 12L, 12R is a differential housing by bearings 26L, 26R at both ends thereof. 18 is supported. The side gear 12L. 12R is configured as a separate member from the left and right axles 24L and 24R for the convenience of assembling the device. Functionally, the left and right axles 24L and 24R are shaft portions of the side gears 12L and 12R, respectively. is there. Both ends of the pinions 14 and 16 are rotatably supported around the pinion shaft 28 supported by the differential case 10. Reference numeral 30 denotes a pin for fixing the axial position of the pinion shaft 28 with respect to the differential case 10.

  The differential case 10 is provided with a pair of cylindrical bores 32L and 32R that rotatably support the pair of side gears 12L and 12R. The inner ends of the pair of cylindrical bores open into a chamber space that accommodates the pair of side gears 12L and 12R, and the outer ends thereof are limited in the differential housing 18 by bearings 26L and 26R and oil seals 34L and 34R. It opens into the room space. In FIG. 1, the differential housing 18 is shown only in a portion that supports both ends of the differential case 10 via bearings 26 </ b> L and 26 </ b> R, but the differential housing 18 is configured as a housing that surrounds the differential case 10. ing.

  FIG. 2 is a longitudinal sectional view showing the differential case 10 used in the differential shown in FIG. 1, and FIG. 3 is a transverse sectional view of the differential case 10 taken along the section 3-3 in FIG. As shown in these drawings, the differential case 10 is provided with openings 36p, 36q for inserting the side gears 12L, 12R and the pinions 14, 16 in the side wall portion thereof. Conventionally, the edge of the opening is an end edge in which a part of the wall is simply cut off around the entire circumference. However, according to the present invention, an inward lubricating oil retaining lip 38p, 38q is provided. In the embodiment shown in FIGS. 2 and 3, the lubricating oil retaining lips 38 p and 38 q are fixed lips formed integrally with the differential case 10. The lubricating oil retaining lips 38p, 38q may be provided along the upper and lower edges of the openings 36p, 36q when the differential case is placed horizontally as shown in FIG.

  When the lubricating oil is dripped onto the differential case 10 from the upper portion of the differential housing 18 by an appropriate lubricating oil supply means not shown in the drawing, when the openings 36p and 36q are directed upward as the differential case rotates. Through these openings, the lubricating oil flows into the differential case and is stored in the differential case to lubricate the meshing portions of the side gears 12L and 12R and the pinions 14 and 16. However, since the differential case rotates, there is a time zone in which these openings are downward as well as a time zone in which the openings 36p and 36q are upward. Inside the differential case passing therethrough while the openings 36p and 36q are downward. If the differential case rotates, and if the differential case rotates, the lubricating oil also flows out from the differential case passing through the openings 36p and 36q by centrifugal force. At this time, if the lubricating oil holding lips 38p and 38q are provided, the lubricating oil is held inside by the lubricating oil holding lips, so that the lubricating oil flows out of the differential case due to gravity or centrifugal force. The amount of lubricating oil retained in the differential case increases as compared with the case where such a lubricating oil retaining lip is not provided.

  The cross-sectional shape of the lubricating oil retaining lips 38p, 38q may be a shape that can retain more lubricating oil in the differential case as illustrated in FIGS. 4 (A) and 4 (B).

  FIG. 5 is similar to FIG. 3 of the embodiment in which the lubricating oil retaining lip having the above-described action is deflected in the direction of narrowing the openings 36p and 36q by the centrifugal force acting with the rotation of the differential case. It is a cross-sectional view of the differential case. In this case, the lubricating oil retaining lips 40p, 40q are pivotally mounted on the differential case main body by the pivot 42 so as to be rotatable in the direction indicated by the arrows in the figure, and by the tension coil spring 44 stretched between the tips. As shown in FIG. 5, they are elastically biased toward the maximum open position where they are aligned in the direction facing each other. This state is a state in which the differential case is not rotating or is rotating at a very low speed even if it is rotating.

  Starting from the state shown in FIG. 5, when the rotational speed of the differential case increases and the centrifugal force acting on the lubricating oil retaining lips 40 p and 40 q increases, these lubricating oil retaining lips resist the spring force of the tension coil spring 44. Then, the openings 36p and 36q are deflected in the direction of narrowing as shown in FIG. The degree of this deflection increases as the rotational speed of the differential case increases, and the apparent shape of the lubricating oil retaining lip becomes a shape that can hold more lubricating oil in the differential case.

  FIG. 7 shows a differential case similar to FIG. 3 of the embodiment in which the lubricating oil retaining lip having the above-described action is deflected in the direction of narrowing the openings 36p and 36q due to the temperature rise of the differential case. It is a cross-sectional view. In this case, the lubricating oil retaining lips 46p, 46q are formed of a bimetal that deforms in response to the temperature of the differential case, and starts from the shape shown in FIG. 7 in which the temperature of the differential case is in a predetermined low state. When the temperature of the differential case rises, the direction of narrowing the openings 36p and 36q as shown in FIG.

  While the present invention has been described in detail with respect to several embodiments thereof, it will be apparent to those skilled in the art that various modifications can be made to these embodiments within the scope of the present invention. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded longitudinal sectional view showing an example of a differential gear incorporating one embodiment of a differential case according to the present invention. The longitudinal cross-sectional view which takes out and shows a differential case from the differential shown in FIG. FIG. 3 is a transverse sectional view of a differential case according to a section 3-3 in FIG. 2. The cross-sectional view of the differential case lip | rip part which shows two other examples of the cross-sectional shape of lubricating oil holding lip. FIG. 4 is a cross-sectional view of the differential case similar to FIG. 3 in the embodiment in which the lubricant holding lip is deflected in the direction of narrowing the opening by the centrifugal force acting with the rotation of the differential case. FIG. 6 is a cross-sectional view of the differential case similar to FIG. 5 when the rotational speed of the differential case increases starting from the state shown in FIG. 5. FIG. 4 is a cross-sectional view of a differential case similar to FIG. 3 of the embodiment in which the lubricant holding lip is deflected in a direction that narrows the opening due to an increase in temperature of the differential case. The cross-sectional view of the differential case similar to FIG. 7 when the temperature of the differential case rises starting from the state shown in FIG. 7.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Differential case, 10f ... Differential case flange part, 12L, 12R ... Side gear, 14, 16 ... Pinion, 18 ... Differential housing, 20 ... Bolt, 22 ... Input gear, 24L, 24R ... Axle, 26L, 26R ... Bearing 28 ... Pinion shaft, 30 ... Pin, 32L, 32R ... Cylindrical bore, 34L, 34R ... Oil seal, 36p, 36q ... Opening, 38p, 38q, 40p, 40q ... Lubricating oil retaining lip, 42 ... Pivot, 44 ... Tension coil spring, 46pp, 46q ... Lubricating oil retaining lip

Claims (8)

  A pair of opposed side gears and at least a pair of pinions engaged therebetween are rotatably supported around their respective central axes, and are rotatably supported around a central axis that coincides with the central axes of the pair of side gears, A differential case that rotates a pair of side gears around their central axis while allowing differential rotation therebetween, and an inward lubricating oil retaining lip is provided at the edge of the opening for inserting the side gear and the pinion. A differential case characterized by having.   The differential case according to claim 1, wherein the lubricating oil retaining lip is a fixed lip formed integrally with the differential case.   2. The differential case according to claim 1, wherein the lubricating oil retaining lip is deflected in a direction of narrowing the opening by a centrifugal force acting with rotation of the differential case.   4. The differential case according to claim 3, wherein the deflection of the lubricating oil retaining lip in the direction of narrowing the opening increases with an increase in the rotational speed of the differential case.   The deflection in the direction of narrowing the opening of the lubricating oil retaining lip that increases as the rotational speed of the differential case increases increases the centrifugal force acting on the lubricating oil retaining lip with the rotation of the differential case and the spring force against it. The differential case according to claim 4, wherein the differential case is determined by the combination.   The differential case according to claim 1, wherein the lubricating oil retaining lip is deflected in a direction of narrowing the opening due to an increase in temperature of the differential case.   The differential case according to claim 6, wherein the deflection of the lubricating oil retaining lip in the direction of narrowing the opening increases with an increase in temperature of the differential case. The deflection of the direction which narrows the said opening of the said lubricating oil holding | maintenance lip by the raise of the temperature of a differential case is performed by the bimetal which is sensitive to the temperature of a differential case. Differential case.

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