JPH0534325U - Fluid fitting - Google Patents

Abstract

(57) [Abstract] [Purpose] To suppress excessive heat generation of the working fluid that generates transmission torque and prevent deterioration of the working fluid. [Structure] The disk 7 fixed to the drive shaft 1 and the cover portion 13 forming the housing 3 are made of materials having different coefficients of thermal expansion, and the disk 7 and the cover portion 13 are relatively rotated in the working chamber 9. Disc 7 freely facing each other
The pair of annular projections 7A and 13A forming a labyrinth groove are provided at the opposing portion between the cover portion 13 and the cover portion 13, and when the temperature of the working fluid in the working chamber 9 rises, the thermal expansion of the disk 7 and the cover portion 13 occurs. The shape of the labyrinth groove is changed according to the difference to reduce the transmission torque and suppress the heat generation amount of the working fluid.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a fluid coupling, and particularly to a fluid coupling suitable for use in a fan coupling device for driving a cooling fan of an internal combustion engine for automobiles.

[0002]

[Prior Art]

 Conventionally, as this type of fluid coupling, for example, one described in JP-A-57-163733 is known.

In such a fluid coupling, a pair of ridges forming a labyrinth groove is provided at a facing portion of a fan (driving member) side rotor and a casing (following member) located in an operation chamber, and the above-mentioned operation is performed. A working fluid storage chamber is connected to the chamber through an inflow passage and a return passage whose opening and closing can be controlled, and the rotor and the casing are made of materials having different thermal expansion coefficients.

Then, by controlling the opening and closing of the inflow passage according to the air temperature after passing through the radiator, the inflow amount of the working fluid from the storage chamber to the working chamber is adjusted, and the torque transmitted from the rotor to the casing is adjusted. It is variable and the working fluid in the working chamber is returned to the storage chamber through the return passage. Further, the rotor and the casing are thermally expanded so as to make the labyrinth groove smaller as the temperature rises, thereby compensating for the decrease in the rotational force transmission capability of the working fluid due to the decrease in the viscosity of the working fluid.

[0005]

[Problems to be solved by the device]

 By the way, in a general fluid coupling, the working fluid generates heat in the labyrinth groove during torque transmission, and the amount of heat generation increases as the input speed increases.

However, in the above-mentioned conventional fluid coupling, the labyrinth groove is made small when the temperature of the working fluid rises. Therefore, when the input rotation speed is high, the calorific value of the working fluid is further increased to deteriorate the working fluid. Could lead to

An object of the present invention is to provide a fluid coupling capable of suppressing excessive heat generation of a working fluid and preventing deterioration of the working fluid.

[0008]

[Means for Solving the Problems]

 The fluid coupling of the present invention is provided with a pair of protrusions that form a labyrinth groove located in a working chamber of a working fluid, at a position where a driving member and a driven member that are relatively rotatably arranged face each other. The driving member and the driven member are made of materials having different coefficients of thermal expansion, and the shape of the labyrinth groove is formed so as to reduce the transmission torque due to the working fluid due to the difference in thermal expansion due to the temperature rise of the working fluid. It is characterized by changing the.

[0009]

[Action]

 In the fluid coupling of the present invention, the driving member and the driven member provided with the pair of projections for forming the labyrinth groove have different coefficients of thermal expansion, and due to the difference in thermal expansion between the members due to the temperature rise of the working fluid, By changing the shape of the labyrinth groove so as to reduce the torque transmitted by the working fluid, when the working fluid becomes hot, the heat generation amount of the working fluid is suppressed and deterioration of the working fluid is prevented.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 are views for explaining a first embodiment of the present invention. The present embodiment is an application example as a fan coupling of an automobile.

In the present embodiment, 1 is a drive shaft that is a drive member having a flange to which a V-belt pulley or the like is attached, and 3 is rotatably supported by the drive shaft 1 via a bearing 5, and the outer periphery thereof is cooled. A housing, which is a driven member to which a fan is attached, is a disk fixed to the front end of the drive shaft 1 and housed in a working chamber 9 described later in the housing 3. The housing 3 includes a body portion 11 that is directly supported by the bearing 5, and a cover portion 13 that is crimped and connected to the front end of the body portion 11. And the working chamber 9 on the rear side. The disk 7 and the cover portion 13 are made of materials having different coefficients of thermal expansion, and in the case of the present embodiment, the former has a higher coefficient of thermal expansion than the latter.

A plurality of annular projections 7A and 13A meshing with each other with a predetermined gap are formed in the vicinity of the outer peripheral end of the disk 7 and the inner end wall of the cover 13, respectively, and between the both projections 7A and 13A. A plurality of annular labyrinth grooves are formed. Then, in the labyrinth groove thereof, the viscous resistance of the working fluid such as silicon oil is obtained to act as a fluid coupling. The meshing state of both projections 7A and 13A changes as shown in FIGS. 2A and 2B due to the difference in thermal expansion between the disk 7 and the cover portion 13 corresponding to the temperature of the working fluid. The change in the meshing state will be described later together with the action.

The annular projection 7A on the disk 7 side is radially notched at four locations 7B at 90 ° intervals along the circumferential direction of the disk 7, and the operation is performed by centrifugal force passing through the notched locations 7B. The fluid is adapted to flow to the outer peripheral end side of the disk 7. Further, the disk 7 is provided with circular holes 7D at six positions at intervals of 60 ° along the circumferential direction.

On the other hand, the cover portion 13 is provided with a bent supply passage 19 and a return passage 21 that communicate the storage chamber 17 and the working chamber 9, and the latter return passage 21 is opened on the working chamber 9 side. A protrusion 23 is provided on one end in the circumferential direction. The projection 23 forms a pump mechanism with the side end surface of the disk 7.

Further, the partition plate 15 is formed with first, second and third communication holes 24, 25 and 26 for communicating the storage chamber 17 with the working chamber 9. Further, the interiors of the storage chamber 17 and the working chamber 9 are partitioned by a sub plate 41 and a plug plate 42. The sub-plate 41 connects the supply passage 19 and the third communication hole 26, and connects the return passage 21 to the first and second communication holes 24 and 25 via the storage chamber 17, The inside of the storage chamber 17 is partitioned. On the other hand, the plug plate 42 is attached to the partition plate 15 so that the second and third communication holes 25 and 26 communicate with each other. Thereby, as a passage for the working fluid in the storage chamber 17 to flow into the working chamber 9, the first passage passing through the first communicating hole 24, the second and third communicating passages 25, 26, and the supply A second passage through the passage 19 is formed.

A rotary shaft 29, in which the central end of the outer spiral bimetal 27 is fixed, is borne in the substantial center of the cover portion 13, and the inner end of the rotary shaft 29 has the above-mentioned first portion. A valve plate 31 that opens and closes the second communication holes 24 and 25 is supported. The outer peripheral end of the spiral bimetal 27 is fixed at a fixed position of the cover portion 13, detects the temperature of the air passing through a radiator (not shown), and rotates the rotating shaft 29 together with the valve plate 31 in accordance with the temperature. It is designed to move.

Next, the operation will be described.

The fan coupling of this embodiment controls the transmission torque according to the ambient temperature near the bimetal 27 and the temperature of the working fluid.

First, immediately after the engine is started and the ambient temperature around the bimetal 27 is low, the valve plate 31 closes the first and second communication holes 24 and 25 by the action of the bimetal 27 to circulate the working fluid. Practically stop. At that time, the working fluid remaining in the labyrinth groove flows to the outside of the disk 7 through the cutout portion 7B due to the centrifugal force, and the pump mechanism described above passes through the return passage 21 to the inside of the storage chamber 17. Sent to. As a result, the working fluid remaining in the labyrinth groove is discharged at the same time when the engine is started, and the housing 3 rotates at a low speed together with the cooling fan.

Next, when the ambient temperature near the bimetal 27 rises, the valve plate 31 gradually opens the first and second communication holes 24 and 25, and the working fluid in the storage chamber 17 is opened. It will flow into the working chamber 9 from 25. Then, a drive torque corresponding to this inflow amount is generated, and the housing 3, and thus the cooling fan, rotate at high speed.

On the other hand, when the temperature of the working fluid is low, as shown in FIG. 2A, the annular projection 7A on the disk 7 side is positioned radially inward (in comparison with the annular projection 13A on the cover portion 13 side). It is meshed in a state in which it is offset toward the arrow A2 direction side). Therefore, when the two annular protrusions 13A, 13A that are adjacent to each other in the radial direction are used as a reference, the annular protrusion 7A on the disc 7 side located in the gap W ₀ between the two annular protrusions 13A, 13A is The gap W ₁ with the annular protrusion 13A on the radially inner side is made smaller than the gap W ₂ with the annular protrusion 13A on the radially outer side (arrow A1 direction side). . As a result, a large transmission torque is generated in the small gap W ₁ .

Next, when the working fluid has a high temperature as the input rotation speed increases, for example, during high-speed running of an automobile in which the input rotation speed increases, the disk 7 is rotated according to the temperature of the working fluid. Thermal expansion is relatively large on the radially outer side. Therefore, in the gap W ₀ between the adjacent annular protrusions 13A, 13A, the gap W ₁ on the radially inner side gradually increases. Then, when the working fluid reaches the maximum temperature, as shown in FIG. 2B, the annular protrusion 7A is located at the center of the adjacent annular protrusions 13A, 13A, and the gaps W ₁ and W ₂ are equal. Become. As a result, the transmission torque decreases as the temperature of the working fluid rises as the input rotation speed rises, the output rotation speed of the housing 3 and thus the cooling fan decreases, and the amount of heat generation of the working fluid decreases. Therefore, the temperature rise of the working fluid is suppressed, and the deterioration of the working fluid is prevented.

Solid lines B1 and B2 in FIG. 3 show the relationship between the temperature change of the working fluid and the output rotation speed with respect to the input rotation speed. In the case of the present embodiment, the time point P at which the gap W ₁ starts to increase becomes P. Therefore, the temperature of the working fluid and the output rotation speed decrease. Dotted lines C1 and C2 in FIG. 3 indicate the characteristics of a conventional fan coupling in which the disk 7 and the cover portion 13 are made of materials having the same coefficient of thermal expansion, and the temperature of the working fluid varies depending on the input rotation speed. As it rises, the working fluid may deteriorate. In this conventional example, the reason why the output rotation speed decreases when the input rotation speed rises above a predetermined value is that the viscosity decreases with the temperature rise of the working fluid.

By the way, in the present embodiment, since the rotation speed of the cooling fan is reduced in order to suppress the temperature rise of the working fluid, there is a concern that the temperature of the radiator rises. However, since the temperature of the working fluid rises when the input speed increases, that is, when the engine speed increases, such as when the vehicle is running at high speed, the radiator is affected by the vehicle speed when the vehicle is running at high speed. It will be cooled and there is no problem.

FIGS. 4A and 4B are views for explaining the second embodiment of the present invention. In the case of the present embodiment, contrary to the first embodiment described above, The thermal expansion coefficient of the cover portion 13 is larger than that of the disk 7, and the annular projection 7A on the disk 7 side is located radially outward (on the arrow A1 direction side) with respect to the annular projection 13A on the cover portion 13 side. It is engaged in a biased state. When the temperature of the working fluid is low, as shown in FIG. 4 (a), when the two annular protrusions 13A, 13A that are adjacent in the radial direction are used as a reference, the gap W ₂ on the radially outer side is in the radial direction. It becomes smaller than the gap W ₁ on the side (direction of arrow A2). On the other hand, when the working fluid becomes hot with the increase of the input rotation speed, the cover portion 13 thermally expands to the outside in the radial direction in accordance with the temperature of the working fluid, and the cover portion 13 is adjacent to the working fluid. In the gap W ₀ between the annular protrusions 13A, 13A, the gap W ₂ on the radially inner side gradually increases. When the working fluid reaches the maximum temperature, as shown in FIG. 4 (b), the annular protrusion 7A is located at the center of the adjacent annular protrusions 13A, 13A, and the gaps W ₁ and W ₂ are substantially equal. Become.

Therefore, as in the case of the first embodiment described above, the transmission torque decreases as the temperature of the working fluid increases with the increase of the input rotation speed, and the output rotation speed of the housing 3 and the cooling fan increases. As a result, the calorific value of the working fluid decreases. Therefore, the temperature rise of the working fluid is suppressed, and the deterioration of the working fluid is prevented.

The shape and number of labyrinth grooves are arbitrary, and the point is to reduce the transmission torque due to the working fluid due to the difference in thermal expansion between the disk 7 and the cover portion 13 due to the temperature rise of the working fluid. It is only necessary that the shape of the labyrinth groove can be changed.

[0029]

[Effect of the device]

 As described above, in the fluid coupling of the present invention, the driving member and the driven member provided with the pair of projections for forming the labyrinth groove are made to have different thermal expansion coefficients, and both members are accompanied by the temperature rise of the working fluid. The labyrinth groove shape is changed so as to reduce the transmission torque due to the working fluid due to the difference in thermal expansion of the working fluid.Therefore, when the working fluid reaches a high temperature, the calorific value of the working fluid is suppressed, It is possible to prevent deterioration of the working fluid.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

2 (a) and 2 (b) are respectively I of FIG.
It is an expanded sectional view showing a different operation state of an I circle part.

FIG. 3 is an explanatory diagram of operating characteristics of the fluid coupling shown in FIG.

4 (a) and 4 (b) are views similar to FIGS. 2 (a) and 2 (b) showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive shaft (driving member) 3 Housing (following member) 7 Disk 7A Annular protrusion (projection) 9 Working chamber 11 Body part 13 Cover part 13A Annular protrusion (projection) 17 Storage chamber 19 Supply passage 21 Return passage

Claims (2)

[Scope of utility model registration request] 1. A fluid coupling in which a pair of projections that form a labyrinth groove are provided in a working chamber of a working fluid at opposing portions of a driving member and a driven member that are arranged so as to be rotatable relative to each other. The driving member and the driven member are made of materials having different thermal expansion coefficients, and change the shape of the labyrinth groove so as to reduce the transfer torque by the working fluid due to the difference in thermal expansion due to the temperature rise of the working fluid. Is a fluid coupling. 2. A pair of first protrusions adjacent to each other in the radial direction is provided on one side of the facing portion between the driving member and the driven member, and the pair of first protrusions is provided on the other side of the facing portion. And a second protrusion that forms a pair of radially inner and radially outer labyrinth grooves between the pair of first protrusions, and one side of the pair of labyrinth grooves is provided. 2. The fluid coupling according to claim 1, wherein the groove width is smaller than that of the labyrinth groove on the other side, and the groove width gradually increases as the temperature rises.