JP2018123834A - Viscous Coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a viscous coupling capable of reducing dragging torque.SOLUTION: A viscous coupling includes a plurality of outer plates 5, and inner plates, wherein the outer plates 5 and the inner plates are alternately arranged. The outer plate 5 includes: a plurality of slits 23 whose inner end is opened, and which directs radially outward; and a triangular-shaped hole 25 that, with one point on a circumferential line C1 defined as an origin corner part 26, is formed substantially symmetrically to a tangent line passing through the origin corner part 26.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a viscous coupling.

  In an automobile, a viscous coupling is generally attached between a propulsion shaft and a final reduction gear, and an example of the structure is described in Patent Document 1. In Patent Document 1, a shaft member and a cylindrical member that are coaxially disposed so as to be relatively rotatable with each other, a plurality of inner plates that rotate integrally with the shaft member, and an inner plate that are alternately disposed and rotate integrally with the cylindrical member There is described a viscous coupling that includes a plurality of outer plates that are filled with silicone oil. The opening of the cylindrical member is closed with a cover, and after assembling the viscous coupling, a predetermined amount of silicone oil is filled from the sealing port provided on the cover.

  For example, if a vehicle runs on a slippery road surface and one of the front and rear wheels idles and a difference in rotational speed occurs between the outer plate and the inner plate, a shearing force acts on the silicone oil, causing the other wheel to Power is transmitted and stable running performance is obtained.

JP-A-10-281186

  In the case of a four-wheel drive vehicle based on a front-wheel drive vehicle, the difference in rotational speed between the outer plate and the inner plate is prevented by the gear ratio of the auxiliary transmission and the final reduction gear. May cause a difference. When driving in this state, the viscous coupling is differential despite the fact that the road surface is not slippery, and power is transmitted to the rear wheels, which originally do not need to transmit power (this is dragged). (Referred to as torque), resulting in poor fuel consumption.

  Patent Document 1 describes that a hole is provided outside the slit in the outer plate. According to this, the shear area on the radially outer side can be reduced by the amount of the holes. Therefore, when the silicone oil is moved radially outward, the outer plate and the inner plate rotate differentially to generate a shearing force of the silicone oil, which can suppress an increase in transmission torque and reduce drag torque. Can also be expected.

  An object of the present invention is to provide a viscous coupling that can more effectively reduce drag torque.

  In order to solve the above-mentioned problem, the present invention is formed between a cylindrical member, a shaft member coaxially disposed so as to be rotatable relative to the cylindrical member, and between the cylindrical member and the shaft member and filled with a viscous fluid. A plurality of outer plates that are disposed in the working chamber and rotate integrally with the cylindrical member, and a plurality of inner plates that are alternately disposed with the outer plate and rotate integrally with the shaft member. A viscous coupling provided, wherein the outer plate has a plurality of slits and a triangular portion formed substantially symmetrically with respect to a tangent passing through the starting corner portion with a point on the circumferential line as a starting corner portion It has the hole which has., It is characterized by the above-mentioned.

  According to the present invention, when the outer plate and the inner plate rotate and the mixture of silicone oil and air enters the hole, the silicone oil having a large specific gravity is collected from the bottom side of the triangular portion. Air is efficiently pushed out from the starting corner portion side by rapidly accumulating the silicone oil by the triangular portion whose interval becomes narrower toward the starting corner portion. Since the triangular portion is formed substantially symmetrical with respect to the tangent line on the circumferential line, the silicone oil is efficiently accumulated in the hole by the rotational force of the outer plate and the inner plate. Since the air extracted from the holes is dispersed and interposed on the shearing surface between the outer plate and the inner plate, the amount of silicone oil on the shearing surface is reduced accordingly, and the drag torque is reduced.

  In the outer plate, the starting corner portion may be located radially inward from the outer end of the slit.

  The present invention also includes a cylindrical member, a shaft member disposed coaxially with the cylindrical member so as to be rotatable relative to the cylindrical member, and a working chamber formed between the cylindrical member and the shaft member and filled with a viscous fluid. A viscous coupling comprising: a plurality of outer plates disposed in the working chamber and rotating integrally with the cylindrical member; and a plurality of inner plates alternately disposed with the outer plate and rotating integrally with the shaft member. The inner plate has a plurality of slits and a hole having a triangular portion formed substantially symmetrically with respect to a tangent passing through the starting corner portion, with one point on the circumferential line as a starting corner portion. It is characterized by having.

  According to the present invention, when the outer plate and the inner plate rotate and the mixture of silicone oil and air enters the hole, the silicone oil having a large specific gravity is collected from the bottom side of the triangular portion. Air is efficiently pushed out from the starting corner portion side by rapidly accumulating the silicone oil by the triangular portion whose interval becomes narrower toward the starting corner portion. Since the triangular portion is formed substantially symmetrical with respect to the tangent line on the circumferential line, the silicone oil is efficiently accumulated in the hole by the rotational force of the outer plate and the inner plate. Since the air extracted from the holes is dispersed and interposed on the shearing surface between the outer plate and the inner plate, the amount of silicone oil on the shearing surface is reduced accordingly, and the drag torque is reduced.

  In the inner plate, the starting corner portion may be located radially outward from the inner end of the slit.

  Moreover, as the shape of the hole, a triangle shape, a rhombus shape, or a shape in which a plurality of arc portions are connected by straight lines or curves is preferable.

  According to the present invention, air can be efficiently extracted from the hole, and drag torque can be reduced by dispersing and interposing the air on the shearing surfaces of the outer plate and the inner plate.

It is a sectional side view of the viscous coupling which concerns on this invention. It is a front view of the outer plate seen from the vehicle front side. It is a front view of the inner plate seen from the vehicle front side. It is a front view of the outer plate and inner plate seen from the vehicle front side. It is an enlarged view of the hole which concerns on this invention. It is explanatory drawing of the conventional circular hole. It is a front view of the outer plate provided with the hole of the 1st modification. It is an enlarged view of the hole of the 1st modification. It is an enlarged view of the hole of the 2nd modification.

  In FIG. 1, a viscous coupling (viscous joint) 1 includes a cylindrical member 2, a cover 3, a shaft member 4, an outer plate 5, and an inner plate 6. The viscous coupling 1 is provided, for example, between a propulsion shaft of an automobile and a final reduction gear. As an example, the cylindrical member 2 is connected to the propulsion shaft, and the shaft member 4 is connected to the drive pinion shaft of the final reduction gear.

  The inner periphery of the cylindrical member 2 is formed on a hole spline 7 that is spline-coupled to the outer edge of the outer plate 5 and on one end side (vehicle rear side) of the hole spline 7 in the axial center O direction. The fitting portion 8 is formed on the other end side (vehicle front side) of the hole spline 7 in the axial center O direction and includes a shaft member support portion 9 having a smaller diameter than the hole spline 7.

  The shaft member support portion 9 is a portion that supports the shaft member 4 so as to be relatively rotatable, and a bearing 10 is interposed between the shaft member support portion 9 and the shaft member 4. A shaft spline 12 having a diameter larger than the outer peripheral surfaces 13A and 13B of the shaft member 4 and splined to the inner edge of the inner plate 6 is formed in the middle of the shaft member 4 in the axis O direction. A seal member 11 is interposed from the shaft member support portion 9 to the one end side opening portion side of the cylindrical member 2 described above, and an outer peripheral surface 13B that is loosely fitted to the cylindrical member 2 is provided on the other end side of the shaft spline 12. It is sealed.

  The cover 3 is fitted into the cover fitting portion 8 so as to close the opening on the one end side of the cylindrical member 2, and is prevented from being detached by the circlip 14. Between the cover 3 and the outer peripheral surface 13A on one end side of the shaft member 4, a bearing 15 and a seal member 16 are interposed. An O-ring 17 is interposed between the cover 3 and the cover fitting portion 8.

  An annular working chamber 18 is configured by being surrounded by the cylindrical member 2, the cover 3, and the shaft member 4. The working chamber 18 includes an outer plate 5 that is splined to the hole spline 7 and rotated integrally with the cylindrical member 2, and an inner plate 6 that is splined to the shaft spline 12 and rotated integrally with the shaft member 4. Silicone oil is sealed as a viscous fluid after being alternately stacked in the direction of the center O. The cover 3 is formed with a filling hole 19 for filling with silicone oil, and an air vent hole 20 for releasing the air in the working chamber 18 to the outside when the silicone oil is filled. An internal thread is screwed into the filling hole 19. After filling with silicone oil, the filling hole 19 is closed by a bolt 21, and the air vent hole 20 is closed by press-fitting a ball 22. The working chamber 18 is filled with a predetermined amount of silicone oil, and air exists in the remaining space.

  As described above, when a rotational speed difference is generated between the outer plate 5 and the inner plate 6 due to, for example, the front wheel idling, a shearing force is generated in the silicone oil between the two plates. Power is transmitted to the rear wheel, and power is transmitted to the rear wheels.

  As shown in FIG. 2, the outer plate 5 has a plurality of slits 23 that are open at the inner end and directed outward in the radial direction at equal intervals in the circumferential direction. The slit 23 forms an inclination angle θ1 on the Q direction (counterclockwise direction in FIG. 2) side that is one rotation direction with respect to the radial line R1 passing through the axis O and the inner end 23A of the slit 23. Is formed. In the figure, the slit 23 is formed in a straight line, but may be formed in a curved line.

  As shown in FIG. 3, the inner plate 6 is formed with a plurality of slits 24 with the outer ends open and directed radially inward at equal intervals in the circumferential direction. The slit 24 is formed so as to form an inclination angle θ2 on the P direction (clockwise direction in FIG. 3) side which is the other rotation direction with respect to the radial line R2 passing through the axis O and the inner end 24A of the slit 24. Has been. Although the slit 24 is formed in a straight line in the figure, it may be formed in a curved line.

  FIG. 4 shows a state in which the outer plate 5 and the inner plate 6 are assembled, and both plates rotate in the P direction when the vehicle moves forward. The rotation speed of the outer plate 5 is the same as that of the output shaft of the auxiliary transmission, and the rotation speed of the inner plate 6 is the same as that of the drive pinion gear of the final reduction gear. Although the rotational speeds of both plates during running are substantially the same, it is almost impossible to make them completely coincide, and the two plates may rotate relative to each other.

  When the outer plate 5 rotates relative to the inner plate 6, the outer plate 5 rotates relative to the inner plate 6 in the P direction (forward rotation). With this rotation, the intersecting region 40 between the slit 23 and the slit 24 moves from the radially inner side toward the radially outer side, so that the silicone oil in the intersecting region 40 is pushed radially outward. As a result, the silicone oil moves as a whole outward in the radial direction, and the air moves correspondingly inward in the radial direction. On the other hand, when the inner plate 6 has a higher rotational speed than the outer plate 5, the outer plate 5 rotates (reverses) relative to the inner plate 6 in the Q direction. With this rotation, the intersecting region 40 moves from the radially outer side toward the radially inner side, so that the silicone oil in the intersecting region 40 is pushed radially inward. As a result, the silicone oil moves as a whole inward in the radial direction, and the air moves correspondingly in the radial direction.

  As shown in FIG. 2, a plurality of holes 25 penetrating the front and back are formed at equal intervals in the circumferential direction near the outer edge of the outer plate 5. As shown in FIG. 3, a plurality of holes 25 penetrating the front and back are also formed at equal intervals in the circumferential direction near the outer edge of the inner plate 6. When the hole 25 is formed in the outer plate 5, the hole 25 may not be formed in the inner plate 6. Further, when the hole 25 is formed in the inner plate 6, the hole 25 may not be formed in the outer plate 5. By providing the hole 25 in at least one of the outer plate 5 and the inner plate 6, the shear area of the silicone oil sandwiched between the outer plate 5 and the inner plate 6 is reduced, so that the shearing force acting on the silicone oil is reduced. Transmission torque can be reduced. Therefore, the drag torque can be reduced when the outer plate 5 and the inner plate 6 are in the normal rotation state and the silicone oil is moved radially outward.

  On the other hand, the present inventor has repeatedly tested the drag torque when the outer plate 5 and the inner plate 6 are in the reverse rotation state and the air moves radially outward, and the drag torque is generated by the following mechanism. I found out. When the air moves in a narrow space between the plates, if the mixture of silicone oil and air flows into the holes 25, the air is difficult to escape from the holes 25. Accordingly, the amount of silicone oil present on the shearing surface between the outer plate 5 and the inner plate 6 increases, so that the drag torque tends to increase. If the air can be extracted from the hole 25, the air can be dispersed on the shear surface, the amount of silicone oil can be reduced, and the drag torque can be reduced.

  FIG. 6 shows a conventional circular hole 51. It is known that when the mixture of silicone oil and air enters the hole 51, the silicone oil having a large specific gravity is distributed on the rear side with respect to the P direction which is the rotation direction of the plate, and the air is distributed on the front side. The inventor obtained the hole 25 having a shape in which air can be easily extracted by performing various tests on the hole shape.

  The hole 25 according to the present invention has a point having a starting point corner portion 26 on one circumferential line C1 and a triangular portion formed substantially symmetrically with respect to a tangent S passing through the starting point corner portion 26. Become. 2 and 3 show a case where the entire shape of the hole 25 has a triangular shape. The starting corner portion 26 is disposed so as to be directed in the P direction that is the rotational direction of the outer plate 5 and the inner plate 6 when the vehicle moves forward.

  As shown in FIG. 5, the hole 25 is substantially symmetrical with respect to the tangent line S and is opposed to the starting corner portion 26 and a pair of side portions 27 and 28 extending so as to intersect at the starting corner portion 26 at an angle θ <b> 3. And a bottom portion 29. The side part 27 and the side part 28 are substantially equilateral to each other. It is desirable that the angle θ3 be an acute angle in the range of approximately 30 to 90 degrees. The starting corner portion 26 does not necessarily need to be an intersection of straight lines, and may have a slight arc shape as shown. Note that the hole 25 does not need to be strictly symmetrical with respect to the tangent S, and may be formed so that the center of the bottom portion 29 is positioned on the circumferential line C1, for example.

  According to the hole 25 having such a triangular portion, the following operation is obtained. When the outer plate 5 and the inner plate 6 rotate in the P direction and the mixture of silicone oil and air enters the hole 25, the silicone oil having a large specific gravity is collected from the bottom portion 29 side. Then, as the silicone oil is quickly accumulated by the side portions 27 and 28 whose intervals become narrower toward the starting corner portion 26, air is efficiently pushed out from the starting corner portion 26 side. Since the side portions 27 and 28 are formed substantially symmetrical with respect to the tangent S on the circumferential line C1, the silicone oil is efficiently accumulated in the holes 25 by the rotational force of the outer plate 5 or the inner plate 6. To go.

  Although the conventional circular hole 51 of FIG. 6 has a structure in which air does not easily escape because there is no corner portion, the hole 25 of the present invention can easily extract air due to the presence of the starting corner portion 26. In particular, if the starting corner portion 26 is set to an acute angle, air can be extracted more easily. The air extracted from the holes 25 is dispersed and interposed on the shearing surfaces of the outer plate 5 and the inner plate 6. Therefore, the amount of silicone oil on the shear surface is reduced correspondingly, and drag torque can be reduced.

  With respect to the position of the hole 25 in the radial direction of the outer plate 5, as shown in FIG. 2, the circumferential line C <b> 1 passing through the starting corner portion 26 is positioned on the radially outer side than the circumferential line C <b> 2 passing through the outer end of the slit 23. doing. That is, the hole 25 is formed such that the starting corner portion 26 is located on the radially outer side than the outer end of the slit 23. However, in some cases, the hole 25 is formed so that the circumferential line C1 is radially inward of the circumferential line C2, that is, the starting corner 26 is positioned radially inward of the outer end of the slit 23. May be.

  As for the position of the hole 25 in the radial direction of the inner plate 6, as shown in FIG. 3, the circumferential line C <b> 1 passing through the starting corner portion 26 is more radially outward than the circumferential line C <b> 3 passing through the inner end of the slit 24. positioned. That is, the hole 25 is formed such that the starting corner portion 26 is positioned on the radially outer side than the inner end of the slit 24. However, depending on the case where the length of the slit 24 is short, the circumferential line C1 is radially inward of the circumferential line C3, that is, the starting corner 26 is radially inward of the inner end of the slit 24. You may form the hole 25 so that it may be located in.

"First modification"
The 1st modification of the hole 25 is exhibiting the rhombus shape as shown in FIG.7 and FIG.8. As shown in FIG. 8, the rhombus-shaped hole 25 has a triangular portion 31 having a starting corner portion 26 at one point on the circumferential line C1 in the right half region with the base portion 29 as a boundary. The half region has a triangular portion 31A having one point on the circumferential line C1 as a starting corner portion 26A. The holes 25 do not need to be formed strictly symmetrical with respect to the tangent line S passing through the starting corner portion 26 or the starting corner portion 26A, and both the starting corner portion 26 and the starting corner portion 26A are circumferential as shown in FIG. You may form so that it may be located on the line C1. Further, the starting corner portion 26 and the starting corner portion 26A may be located on the radially outer side than the circumferential line C2 passing through the outer end of the slit 23, or may be located on the radially inner side. Although FIG. 7 shows the case where the hole 25 is formed in the outer plate 5, it may be formed in the inner plate 6.

  According to the hole 25 having a rhombus shape, for example, when the vehicle moves forward, one triangular portion 31 can efficiently extract air from the starting corner portion 26, and when the vehicle moves backward, the other triangular portion 31A Air can be efficiently extracted from the starting corner portion 26A. Therefore, drag torque can be reduced regardless of whether the vehicle is moving forward or backward.

"Second modification"
As shown in FIG. 9, the second modification of the hole 25 has a shape in which a plurality of arc portions 35, 36, and 37 are connected by straight lines or curves. In the hole 25, the starting corner portion 26 of the triangular portion 31A is formed in the arc portion 35, and the remaining two corner portions are also formed in the arc portions 36 and 37, respectively. The side portions 27 and 28 and the bottom portion 29 are each formed in a curve that is convex toward the inside of the hole 25. In addition, you may form the side parts 27 and 28 and the base part 29 in a straight line. Further, for example, the side portions 27 and 28 may be formed in a curved line, and the bottom side portion 29 may be formed in a straight line. For example, the curved line and the straight line may be combined. Even with the hole 25 having the above-described shape, air can be efficiently extracted from the starting corner portion 26 by a shape similar to the triangular portion 31 when the vehicle moves forward, and drag torque can be reduced.

  The preferred embodiment of the present invention has been described above. When the slit 23 is formed with an inclination angle θ1 on the outer plate 5, the slit 24 may be formed along the radial direction in the inner plate 6. In addition, when the slit 24 is formed with the inclination angle θ2 on the inner plate 6, the slit 23 may be formed along the radial direction in the outer plate 5.

1 Viscous coupling 2 Cylindrical member 3 Cover 4 Shaft member 5 Outer plate 6 Inner plate 23 Slit (outer plate side)
24 Slit (Inner plate side)
25 Hole 26 Starting corner 27, 28 Side 29 29 Bottom 31 Triangular

Claims (7)

A cylindrical member;
A shaft member disposed coaxially with the cylindrical member so as to be relatively rotatable;
A working chamber formed between the cylindrical member and the shaft member and filled with a viscous fluid;
A plurality of outer plates that are disposed in the working chamber and rotate integrally with the cylindrical member, and a plurality of inner plates that are alternately disposed with the outer plate and rotate integrally with the shaft member;
A viscous coupling comprising:
The outer plate is
A plurality of slits;
A hole having a triangular portion formed in a substantially symmetrical shape with respect to a tangent line passing through the starting corner portion, with one point on the circumferential line as a starting corner portion,
A viscous coupling characterized by comprising:   2. The viscous coupling according to claim 1, wherein the starting corner is positioned radially inward from an outer end of the slit. A cylindrical member;
A shaft member disposed coaxially with the cylindrical member so as to be relatively rotatable;
A working chamber formed between the cylindrical member and the shaft member and filled with a viscous fluid;
A plurality of outer plates that are disposed in the working chamber and rotate integrally with the cylindrical member, and a plurality of inner plates that are alternately disposed with the outer plate and rotate integrally with the shaft member;
A viscous coupling comprising:
The inner plate is
A plurality of slits;
A hole having a triangular portion formed in a substantially symmetrical shape with respect to a tangent line passing through the starting corner portion, with one point on the circumferential line as a starting corner portion,
A viscous coupling characterized by comprising:   2. The viscous coupling according to claim 1, wherein the starting corner portion is located radially outside the inner end of the slit.   The viscous coupling according to any one of claims 1 to 4, wherein the hole has a triangular shape.   The viscous coupling according to any one of claims 1 to 4, wherein the hole has a rhombus shape.   The viscous coupling according to any one of claims 1 to 4, wherein the hole has a shape in which a plurality of arc portions are connected by straight lines or curves.

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