JP2786444B2 - Engine integrated differential structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine-integrated differential structure in which a differential mechanism is disposed in a differential case formed integrally with an engine case.

2. Description of the Related Art Conventionally, in a front-wheel drive or four-wheel drive vehicle having a vertical engine, a transmission including a torque converter (or a clutch) and a transmission mechanism is connected to the rear end of the engine, and the transmission A configuration in which a differential mechanism (differential mechanism) is provided between the torque converter and the speed change mechanism is generally used.

However, this configuration has a problem that the overhang of the engine in front of the vehicle is large, and the weight distribution of the vehicle is likely to be uneven. Therefore, as disclosed in Japanese Patent Publication No. 58-24289, a differential mechanism is provided. Is also provided immediately below the engine. However, in the case of this configuration, the mounting position of the engine is increased, and accordingly, the position of the front bonnet is raised to deteriorate the forward visibility, and the center of gravity of the engine is raised, and the stability of the vehicle is reduced. There is a problem.

In order to solve the above-mentioned problem, the applicant of the present invention has disclosed in Japanese Patent Application No. 62-313830, etc., this engine case (consisting of an engine oil pan, a crankcase, etc.) An engine-integrated differential structure in which a differential case is integrally formed and a differential mechanism is arranged in the differential case has been proposed. Incidentally, the differential mechanism is usually composed of a hypoid gear, a bevel gear and the like, a final reduction gear set for performing orthogonal transformation and deceleration in the rotational direction,
A differential gear set for dividing and transmitting the driving force to the left and right wheels and adjusting the rotation difference therebetween.

Here, different oils are used for the engine oil put in the engine case and the differential oil put in the differential case because the requirements such as lubricity are different. For this reason, in the engine-integrated differential structure, a partition wall is provided for partitioning the internal space of the engine case from the internal space of the differential case in order to prevent mixing of the engine oil and the differential oil.

(Problems to be Solved by the Invention) When comparing engine oil and differential oil, first, there is a difference that the differential oil has a higher viscosity than the engine oil. For this reason, at the time of starting at a low temperature, there is a problem that the driving resistance of the differential mechanism is large and the running resistance is large. In such a case, the temperature of the engine oil rapidly rises due to the heat from the engine, but the differential oil remains sealed in the differential case and its temperature rise is small, and when traveling in a low temperature state The problem of the driving resistance is large.

Further, since the engine is air-cooled or water-cooled, the engine oil during operation is maintained within a predetermined temperature, and the temperature is prevented from becoming excessively high. On the other hand, the temperature of the differential oil rises due to heat generated by agitation and friction caused by the rotation of the differential mechanism during traveling. For example, when high-speed running is continued for a long time, there is a problem that the temperature of the differential oil becomes extremely high and the deterioration of the differential oil is accelerated.

The present invention has been made in consideration of the problem of running resistance due to the viscosity of the differential oil at the time of low temperature start as described above and the problem of oil deterioration due to an excessive rise in the temperature of the differential oil during running, and has a differential structure of an engine integrated type. In view of the features described above, an object of the present invention is to provide a structure that can solve the above problem.

B. Configuration of the Invention (Means for Solving the Problems) As means for achieving the above object, an engine-integrated differential structure according to the present invention is configured such that an engine case and a differential case are integrally formed and an engine formed in this manner. The partition wall that separates the space inside the case from the space inside the differential case employs a heat conduction improving structure that improves heat exchange between engine oil in the engine case and differential oil in the differential case.

(Operation) When the above-described differential structure is used, at the time of low temperature starting of the vehicle, the temperature of the engine oil in the engine case is rapidly increased by receiving heat from the engine during the warm-up operation of the engine. The heat is also transmitted to the differential oil in the differential case by the heat conduction improving structure adopted for the partition wall, and the temperature of the differential oil is rapidly increased. For this reason, the viscosity of the differential oil also decreases rapidly, and the driving resistance of the differential mechanism at the time of starting decreases.

Also, when the temperature of the differential oil increases due to continuous high-speed running, etc., the engine oil is maintained at a predetermined temperature or lower by cooling the engine itself. The improved structure is transmitted to the engine oil, and prevents the temperature of the differential oil from rising excessively.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing an automobile provided with an engine-integrated differential structure according to the present invention, and a driving device including an engine 10, a transmission 30, and a differential device 60 is mounted at the front of the automobile. ing. FIG. 2 schematically shows the drive device taken out. The engine 10 is disposed so that its crankshaft extends in the front-rear direction of the vehicle body, and a transmission 30 is coupled to the rear end thereof. A differential device 60 at the lower left side of the engine 10 is integrally mounted. The engine output shaft is connected on the same axis as the transmission input shaft 32 via a torque converter 31, and a counter is provided between the transmission input shaft 32 and a counter shaft 33 disposed in parallel with the transmission input shaft 32. A shaft type speed change mechanism is provided. The transmission counter shaft 33 is connected to a transmission output shaft 34 via an output gear set.

The differential device 60 includes a space 66 in a differential case 65 integrally formed with the oil pan 25 (engine case) of the engine 10.
, Hypoid gear set (final drive pinion 62
a differential mechanism 61 comprising a set of a and a final ring gear 62b) and a differential gear set. The differential mechanism 61 is separated from the transmission 30 and joined to the lower side of the engine 10. The transmission output shaft 34 is substantially coaxial with the input shaft (ie, the final drive pinion shaft) 62c of the differential device 60,
It is connected to a final drive pinion shaft 62c via an intermediate shaft 90.

The engine room and the vehicle compartment are separated by a dash panel 96 and a floor panel 97, and the engine 10 and the differential device 60 are disposed in the engine room, and the transmission 30
Is protruded from the engine room into a tunnel portion 97a formed on the floor panel 97 so as to extend in the front-rear direction of the vehicle body.

Engine 10 having the above configuration and differential device integrated therewith
FIG. 3 is a cross-sectional view of FIG. 60 taken along arrow III-III.

The engine 10 is an in-line multiple-cylinder engine, and its cylinder axis is inclined leftward (rightward of the vehicle body) when viewed from the front of the vehicle with respect to a vertical plane, as shown in FIG. The engine 10 has a cylinder block 12 in which a piston 13 is slidably accommodated in the cylinder axis direction, and is joined to an upper surface of the cylinder block 12 to form intake and exhaust passages 18a, 18b.
Having an engine case including a cylinder head 11 having intake and exhaust valves 17a and 17b for opening and closing these passages, and an oil pan 25 joined to a crankcase portion 12a forming a lower portion of the cylinder block 12. The engine oil is filled in a space 20 in the engine case.

An intake passage 18a is opened on the side of the cylinder head 11 on the side opposite to the inclined side of the engine 10, and an intake manifold is formed on the side opposite to the inclined side so as to communicate with the opening.
An exhaust passage 18b is opened on the inclined side surface of the cylinder head 11, and an exhaust manifold 27 is provided on the inclined side surface so as to communicate with the exhaust passage 18b.
Is attached.

Further, a camshaft 19a having a plurality of cams 19b extending back and forth is disposed above the cylinder head 11, and the cam 19b causes the rocker arm 19c to rotate by the rotation of the camshaft 19a synchronized with the engine rotation. The intake and exhaust valves 17a, 17b are opened / closed via the opening / closing operation. The camshaft 19a, the rocker arm 19c, and the like are covered by a head cover 11a attached to the upper surface of the cylinder head 11.

Crankcase part 12 that forms the lower part of cylinder block 12
In a, a crankshaft 15 is attached which is located in the engine case internal space 20 and extends back and forth, and an upper part of a connecting rod 14 rotatably attached to the crank part 15a is connected to the piston 13. I have.
Therefore, the crankshaft 15 is driven to rotate in accordance with the reciprocating motion of the piston 13. The crankshaft 15 has a crankshaft.
A balance weight portion 16 protruding on the opposite side to 15a is formed.

The oil pan 25 is joined to the lower surface of the crankcase portion 12a of the cylinder block 12, and this joining surface 28 is formed at a right angle to the cylinder axis as shown in FIG. It is inclined by the same angle as.

A differential device 60 is provided on a side surface of the oil pan 25 on the side opposite to the inclined side of the engine 10. This differential device 60
A differential case including a case 65a integrally formed with the oil pan 25 and a cover 65b fixed to the case 65a.
The differential case 65 includes a differential mechanism 61 disposed in the differential case 65, and differential oil is contained in an internal space 66 of the differential case 65.

The differential mechanism 61 includes a hypoid gear set including a final drive pinion 62a and a final ring gear 62b, and a differential gear set 63 including four bevel gears 63a to 63d. In the differential gear set 63, bevel gears 63c and 63d (not shown) facing each other are rotatably supported by a final ring gear 62b, and the bevel gears 63a and 63b are coupled to left and right axle shafts 71 and 72. Therefore, the engine power transmitted to the transmission output shaft 34 is decelerated by the hypoid gear set, then divided and transmitted to the left and right axle shafts via the differential gear set 63, and the left and right wheels are driven. .

In this case, the left axle shaft 71 extending on the anti-inclination side of the engine 10 extends as it is and is connected to the left front wheel.
Engine case (oil pan 25 and cylinder block
12 and a half shaft 72 supported by a shaft support member 75 attached to the inclined side surface of the crank case portion 12a, extending through the inside of the crank case portion 12a), and connected to the half shaft 72 and further extending outward. Second shaft 73
The second shaft 73 is connected to the right front wheel.

In the engine-integrated differential structure having the above-described configuration, the engine oil that is put into the engine case internal space 20;
Since the type of oil is different from the type of differential oil put in the differential case internal space 66, a partition wall 21 for partitioning these oils is formed between the two spaces 20, 66. Further, the partition wall 21 is provided with a plurality of heat transfer ribs 22a and 22b extending from both sides thereof.

FIG. 4 is a perspective view showing this structure in detail, and FIG. 5 is a cross-sectional view showing the same. A case 65a is formed integrally on the side surface of the engine oil pan 25 so as to protrude outward. The differential case 65 is formed by attaching the cover 65b. And the space inside the differential case 65
Partition wall that partitions 66 and engine case space 20
Although 21 is provided, from this partition wall 21,
A plurality of heat transfer ribs 22a are formed to protrude toward the engine case internal space 20, and a plurality of heat transfer ribs 22b are formed also toward the differential case internal space 66.
Are formed to protrude, and these form a heat conduction enhancing structure.

For this reason, at the time of cold start, the engine oil is first warmed by the warm-up operation of the engine,
The heat of this engine oil is transferred to the heat transfer rib 22
The oil is easily transmitted to the differential oil in the differential case 66 via the heat conduction improving structure including the a, 22b and the partition wall 21, and the differential oil 66 is also warmed. As a result, the viscosity of the differential oil rapidly decreases even at a low temperature start, and the driving resistance of the differential mechanism decreases. In the case of high-speed continuous running or the like, when the temperature of the differential oil rises due to the rotation of the differential mechanism, the heat of the differential oil is transmitted to the engine oil via the heat conduction improving structure. Here, since the engine is air-cooled or water-cooled and the engine oil does not become excessively hot, the temperature of the differential oil is prevented from becoming excessively high.

The structure for improving heat conduction is not limited to the above structure. For example, the partition wall 121 may be formed by the arrow V- in FIG.
The sectional shape along the V may be configured to be zigzag as shown in FIG. 6 so that the contact area between the engine oil and the differential oil and the partition wall 121 may be increased. Heat conduction between the engine oil and the differential oil is good.

Further, the partition wall may be made of a material having excellent thermal conductivity.

C. Effect of the Invention As described above, according to the present invention, the heat exchange between the engine oil in the engine case and the differential oil in the differential case is improved by the partition wall that separates the internal space of the engine case from the internal space of the differential case. When the vehicle is started at a low temperature, the heat of the engine oil, which is heated by the heat from the engine during the warm-up operation of the engine, is used for the partition walls when the vehicle is started at low temperatures. Since the temperature of the differential oil is rapidly increased by being transmitted to the differential oil in the differential case by the heat conduction improving structure, the viscosity of the differential oil is rapidly reduced, and the driving resistance of the differential mechanism at the time of starting is reduced, and the traveling resistance is reduced. Can be smaller. Also, when the temperature of the differential oil increases due to continuous high-speed running or the like, conversely, the heat of the differential oil falls below the predetermined temperature due to the cooling of the engine itself via the heat conduction improving structure of the partition wall. It is possible to prevent the temperature of the differential oil from being excessively increased by being transmitted to the engine oil, and to suppress the high-temperature deterioration of the differential oil.

[Brief description of the drawings]

1 is a side view of an automobile having an engine-integrated differential structure according to the present invention, FIG. 2 is a schematic diagram showing the engine-integrated differential structure and a transmission, and FIG. FIG. 4 is an enlarged sectional view taken along the arrow III-III, FIG. 4 is a perspective view showing an engine oil pan constituting the engine-integrated differential, and FIG. 5 is a view showing a heat conduction improving structure employed for a partition wall of the oil pan. FIG. 6 is a sectional view taken along the arrow VV in FIG. 2, and FIG. 6 is a sectional view showing a different example of the heat conduction improving structure. 20 ... internal space of the engine case, 21 ... partition walls 21a, 21b ... heat transfer rib 25 ... oil pan, 30 ... transmission 51a, 52a ... lip section 60 ... differential device, 65 ... differential case 66 …… Space inside the differential case, 72 …… Half shaft

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 57/02 F01P 3/12

Claims (1)

(57) [Claims] An engine-integrated differential structure in which a differential mechanism is disposed in a differential case formed integrally with an engine case, wherein a partition wall that separates the internal space of the engine case and the internal space of the differential case includes: An engine-integrated differential structure, characterized by employing a heat conduction improving structure for improving heat exchange between engine oil in the engine case and the differential oil in the differential case.