JP2018151010A - Fan coupling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit corotation of a cooling fan at the time of engine starting.SOLUTION: A fan coupling device 200 includes: a driving shaft 210 which is rotationally driven; a rotor 220 integrated with the driving shaft 210; a casing 240 which houses the rotor 220 and is fixed to the driving shaft 210 so as to enable relative rotation; a plate 250 which partitions a rotor 220 side torque transmission chamber 280 from a working fluid storage chamber 290 at the opposite side of the rotor 220 side torque transmission chamber 280; a first valve mechanism 260 which opens or closes a valve hole 250A of the plate 250 according to a surrounding temperature; and a second valve mechanism 270 which is disposed in the middle of a discharge passage 244F formed at an outer periphery part of the casing 240. The second valve mechanism 270 closes the discharge passage 244F when a rotation speed of the casing 240 is less than a predetermined rotation speed and opens the discharge passage 244F when the rotation speed of the casing 240 is faster than or equal to the predetermined rotation speed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fan coupling device that is disposed between a pulley driven by an engine and a cooling fan, and adjusts the driving force of the cooling fan according to the engine temperature.

  In a vertically mounted engine mounted on a rear wheel drive vehicle or the like, a cooling fan is rotated using a rotational driving force of a crankshaft extending in the front-rear direction of the vehicle to increase the amount of air passing through the core of the radiator. In this case, since the cooling fan is rotated by the operation of the engine, for example, in the cold state immediately after the engine is started, the warm-up of the engine is not promoted. Therefore, as described in Japanese Patent Application Laid-Open No. 2012-107727 (Patent Document 1), it is arranged between a pulley driven by an engine and a cooling fan, and adjusts the driving force of the cooling fan according to the engine temperature. A fan coupling device is used.

  The fan coupling device supplies the working fluid from the storage chamber to the torque transmission chamber via a valve hole that opens when the engine temperature exceeds a predetermined temperature, and transmits the rotation of the pulley to the cooling fan. The working fluid supplied to the torque transmission chamber is discharged to the storage chamber through a discharge passage formed in the peripheral portion using a pressure difference generated in the storage chamber and the torque transmission chamber due to a difference in internal rotation speed. The

JP 2012-107727 A

  By the way, if the discharge passage is positioned below when the engine is stopped, the pressure difference due to the difference in rotational speed does not occur, so the working fluid in the storage chamber flows back to the torque transmission chamber due to gravity and is supplied to the torque transmission chamber. There is a risk that. When the engine is started in this state, a so-called “rotation” occurs in which the rotation of the pulley is transmitted to the cooling fan by the working fluid present in the torque transmission chamber. When the cooling fan is accompanied, the driver of the vehicle is likely to notice this, which becomes one of the factors that impair the quietness of the vehicle, for example.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fan coupling device that suppresses the rotation of a cooling fan when the engine is started.

  Therefore, the fan coupling device includes a drive shaft that is rotationally driven, a disk-shaped rotor integrated with the drive shaft, a casing that is housed in the rotor and fixed to the drive shaft so as to be relatively rotatable, and a casing. A plate that is located on a cross section perpendicular to the axial direction of the rotor and defines a torque transmission chamber on the rotor side and a storage chamber for the working fluid on the opposite side, and is formed on the outer periphery of the plate according to the ambient temperature A first valve mechanism that opens and closes the valve hole, and a second valve mechanism that is disposed in the middle of a discharge passage formed in the outer peripheral portion of the casing so as to discharge the working fluid from the torque transmission chamber to the storage chamber. It is equipped with. The second valve mechanism closes the discharge passage when the rotation speed of the casing is less than the predetermined rotation speed, and opens the discharge passage when the rotation speed of the casing is equal to or higher than the predetermined rotation speed.

  According to the present invention, it is possible to suppress the rotation of the cooling fan when starting the engine.

It is a side view which shows an example of an engine cooling device. It is a longitudinal section showing an example of a fan coupling device. It is a longitudinal cross-sectional view which shows an example of the flow-path control valve of a valve closing state. It is explanatory drawing of the force which acts on the valve body of a flow-path control valve in a valve closing state. It is a longitudinal cross-sectional view which shows an example of the flow-path control valve of a valve opening state. It is explanatory drawing of the force which acts on the valve body of a flow-path control valve in a valve opening state.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of an engine cooling device.

  A pulley 120 for taking out a driving force for driving various auxiliary machines such as a compressor of an air conditioner and a water pump of a cooling device is fixed to the tip of the crankshaft 110 of the vertical engine 100. The rotational driving force of the pulley 120 is transmitted to, for example, a pulley 150 fixed to the tip end of the driving shaft 140 of the water pump via a belt 130 wound around the pulley 120. The rotational driving force of the pulley 120 can be transmitted not only to the water pump but also to other auxiliary machines such as a compressor.

  On one side of the pulley 150, specifically, on the side opposite to the engine 100, a plurality of air passages that increase the amount of air passing through the core of the radiator 160 disposed in front of the vehicle via the fan coupling device 200. A cooling fan 170 having a plurality of blades is fixed. The fan coupling device 200 adjusts the driving force of the cooling fan 170 according to the engine temperature.

  As shown in FIG. 2, the fan coupling device 200 includes a drive shaft 210, a rotor 220, a bearing 230, a casing 240, a plate 250, a first valve mechanism 260, and a second valve mechanism 270. .

  The drive shaft 210 has a stepped cylindrical shape having a large-diameter portion 210A and a small-diameter portion 210B, and a disc-shaped flange 210C for fixing to one surface of the pulley 150 is integrally formed at the tip of the large-diameter portion 210A. Has been. The drive shaft 210 is detachably fastened to one surface of the pulley 150 via a flange 210C by a fastener including a bolt and a washer, for example. Therefore, the drive shaft 210 is rotationally driven by the pulley 150 when the engine 100 is operating.

  A disc-shaped rotor 220 is integrated with the tip of the small diameter portion 210B of the drive shaft 210 by, for example, press fitting. Here, the disc shape is not limited to a disc shape with a constant thickness, and for example, as shown in FIG. 2, for the purpose of improving the fixing strength, You may have a truncated cone-shaped part which the center part protrudes. In addition, a plurality of annular portions 220 </ b> A having an annular shape are formed on one surface of the outer peripheral portion of the rotor 220 so as to project away from the drive shaft 210. The plurality of annular portions 220 </ b> A are not limited to one surface of the outer peripheral surface of the rotor 220, and may be formed to protrude on both surfaces.

  An inner ring of a bearing 230 such as a ball bearing is fixed between the stepped portion 210B of the drive shaft 210 and the stepped portion transitioning to the large diameter portion 210A and the other surface of the rotor 220 by, for example, press fitting. ing. Here, the bearing 230 preferably has a sealing function capable of suppressing leakage of a working fluid such as silicon oil. Further, the bearing 230 is not limited to a ball bearing, and a roller bearing or the like can also be used.

  A casing 240 that accommodates the rotor 220 therein is fixed to the outer peripheral surface of the outer ring of the bearing 230 by, for example, press fitting. Therefore, the casing 240 is fixed to the drive shaft 210 so as to be relatively rotatable while accommodating the rotor 220. The casing 240 includes a first casing 242 and a second casing 244 that can be divided so that the rotor 220 and the like can be incorporated therein, and a sealing member 246 such as an O-ring that seals the joint surfaces thereof. It is configured. Here, the first casing 242 and the second casing 244 are detachably fastened by a fastener including a bolt and a washer, for example, and an integrated casing 240 is configured.

  The first casing 242 connects the cylindrical portion 242A fixed to the outer ring of the bearing 230, the annular portion 242B whose plate surface is located on the transverse section of the cylindrical portion 242A, and the cylindrical portion 242A and the annular portion 242B. And a connecting portion 242C. Here, one surface of the first casing 242, i.e., the surface facing the rotor 220, has a predetermined interval with the other surface of the rotor 220 so that relative rotation with the rotor 220 is possible.

  The second casing 244 has a stepped columnar shape that opens on the joint surface side with the first casing 242 and decreases in two stages from the large diameter portion 244A and the small diameter portion 244B toward the back in the axial direction. Has an inner peripheral surface. A circumferential groove 244C having a rectangular cross section for fitting the seal member 246 is formed in the outer peripheral portion of the open end of the large diameter portion 244A. In addition, a plurality of ring-shaped steps that are fitted with a plurality of annular portions 220A of the rotor 220 with a predetermined interval in an annular step located between the large-diameter portion 244A and the small-diameter portion 244B. The annular portion 244D is formed to protrude. Further, the peripheral edge portion of the disc-shaped plate 250 is fitted to the corner portion that transitions from the annular step portion located between the large diameter portion 244A and the small diameter portion 244B to the small diameter portion 244B, An annular fitting portion 244E is formed.

  The plate 250 is fixed to the fitting portion 244E of the second casing 244 by, for example, press fitting. Therefore, the plate 250 is positioned on a cross section perpendicular to the axial direction of the casing 240 and divides the inside of the casing 240 into two in the axial direction. Specifically, the plate 250 transmits a rotational driving force (torque) from the rotor 220 to the casing 240 by the working fluid to the rotor 220 side, that is, the large diameter portion 244A side of the second casing 244. Partition. The plate 250 defines a working fluid storage chamber 290 on the opposite side of the torque transmission chamber 280, that is, on the small diameter portion 244 B side of the second casing 244. Furthermore, at least one valve hole 250 </ b> A that connects the torque transmission chamber 280 and the storage chamber 290 is formed on the plate surface of the plate 250 so as to face the outer peripheral portion of the small diameter portion 244 </ b> B of the second casing 244. Has been.

  At the outer peripheral portion of the second casing 244, the working fluid in the torque transmission chamber 280 is discharged to the storage chamber 290 using a pressure difference caused by the rotational speed difference between the rotational speed of the rotor 220 and the rotational speed of the casing 240. A discharge passage 244F is formed. Details of the discharge passage 244F will be described later.

  The first valve mechanism 260 opens and closes the valve hole 250 </ b> A formed in the outer peripheral portion of the plate 250 according to the ambient temperature closely related to the engine temperature. That is, the first valve mechanism 260 closes the valve hole 250A of the plate 250 when the ambient temperature is lower than the predetermined temperature in order to satisfy the warm-up promotion and cooling requirements of the engine 100, and the ambient temperature is the predetermined temperature. In the above case, the valve hole 250A of the plate 250 is opened. Here, the predetermined temperature may be a temperature at which the engine 100 needs to be cooled, for example.

  The first valve mechanism 260 includes a spiral bimetal 262 that deforms according to the ambient temperature, a hat-shaped valve body 264 that is detachably connected to the valve hole 250A of the plate 250, and a deformation of the bimetal 262. And a rod 266 that transmits the generated rotation to the valve body 264 instead of linear movement in the axial direction.

  The bimetal 262 is fixed to a cylindrical holder 244G formed at the center of the outer surface of the second casing 244. The valve body 264 is arranged so that the valve hole 250A of the plate 250 is closed by one surface of the peripheral edge thereof. The rod 266 is screw-engaged with a boss portion 244H formed on the second casing 244 so as to reciprocate in the axial direction when rotated by deformation of the bimetal 262. Here, the rod 266 is screw-engaged with the boss portion 244H so as to be displaced away from the plate 250 as the ambient temperature rises.

  Therefore, immediately after the engine 100 is started in the cold state, the ambient temperature is relatively low, and the deformation amount of the bimetal 262 is small. For this reason, the rotation caused by the deformation of the bimetal 262 is also small, and the valve body 264 remains blocking the valve hole 250 </ b> A of the plate 250 even if this is replaced by the linear motion by the rod 266. In this state, since the working fluid is not supplied from the storage chamber 290 to the torque transmission chamber 280, no working fluid exists between the annular portion 220A of the rotor 220 and the annular portion 244D of the second casing 244. The rotational driving force of the rotor 220 is not transmitted to the casing 240.

  As the engine 100 warms up and the ambient temperature gradually increases, the amount of deformation of the bimetal 262 gradually increases as the temperature increases. When the deformation amount of the bimetal 262 increases, the rod 266 connected to the bimetal rotates, and the rod 266 is displaced in a direction away from the plate 250. Then, the valve body 264 connected to the rod 266 moves in a direction away from the plate 250, and when the amount of movement increases to some extent, the valve hole 250A of the plate 250 is opened. When the valve hole 250A of the plate 250 is opened, the working fluid is supplied from the storage chamber 290 to the torque transmission chamber 280, and exists between the annular portion 220A of the rotor 220 and the annular portion 244D of the second casing 244. The rotational driving force of the rotor 220 is transmitted to the casing 240 by the working fluid.

  The working fluid supplied to the torque transmission chamber 280 is discharged to the storage chamber 290 via the discharge passage 244F using a pressure difference caused by the rotation speed difference between the rotation speed of the rotor 220 and the rotation speed of the casing 240. Is done.

  The second valve mechanism 270 is disposed in the middle of the discharge passage 244F of the second casing 244. When the rotation speed of the casing 240 is less than the predetermined rotation speed, the second passage mechanism 270 closes the discharge passage 244F and the rotation speed of the casing 240 is predetermined. When the rotation speed is exceeded, the discharge passage 244F is opened. Here, the predetermined rotation speed can be considered that the engine 100 has stopped, for example, can be lower than the rotation speed when the engine 100 is idling.

  The second valve mechanism 270 includes a cylindrical valve body 272 and a compression coil spring 274 that can be cited as an example of an elastic member. In order to arrange the second valve mechanism 270 in the middle of the discharge passage 244F, the discharge passage 244F extends radially outward from the outer edge of the storage chamber 290 and opens to the outer peripheral surface of the second casing 244. The passage 244F1 and the second passage 244F2 that extends from the first passage 244F1 in the orthogonal direction and opens to the outer peripheral portion of the torque transmission chamber 280 are configured. In the first passage 244F1, the outer peripheral surface side of the second casing 244 is expanded so that the valve body 272 and the compression coil spring 274 can be incorporated from the outside of the second casing 244, and the expanded diameter portion thereof. A conical valve seat 244F3 on which the valve body 272 is detachably seated is formed at the innermost part. Here, the valve seat 244F3 is formed in a direction facing the storage chamber 290 in the first passage 244F1. In addition, the second passage 244F2 is connected to the enlarged diameter portion of the first passage 244F1. The valve body 272 is not limited to a cylindrical shape, and may have, for example, a spherical shape or a conical shape.

  Then, from the outside of the outer peripheral surface of the second casing 244, the valve body 272 and the compression coil spring 274 are inserted in this order into the enlarged diameter portion of the first passage 244F1, and an opening is formed in the outer peripheral surface of the second casing 244. The end portion of the first passage 244F1 is closed by the cap 276. In this way, the compression coil spring 274 can bias the valve body 272 toward the valve seat 244F3, that is, bias the valve body 272 toward the valve closing direction. Here, the valve body 272 of the second valve mechanism 270 is disposed at a predetermined interval from the inner peripheral surface of the enlarged diameter portion so that the enlarged diameter portion of the first passage 244F1 can reciprocate in the axial direction. ing.

In the second valve mechanism 270, the mass of the valve body 272, the dimensions of each part, the spring constant of the compression coil spring 274, the natural length, and the like can be determined as follows.
When the discharge passage 244F is positioned below when the engine 100 is stopped, the second valve mechanism 270 prevents the working fluid in the storage chamber 290 from flowing back to the torque transmission chamber 280 via the discharge passage 244F due to gravity. To do. Therefore, in a state where the engine 100 can be regarded as being stopped, as shown in FIG. 3, the valve body 272 is pressed toward the valve seat 244F3, and the discharge passage 244F is closed.

The valve body 272 of the second valve mechanism 270 has a valve opening force for moving the valve body 272 in the valve opening direction (radially outward) and a valve closing force (radially inward). The valve closing force is acted on. In order to consider this valve opening force and valve closing force, the following constants and variables are defined.
mo: mass of the working fluid existing in the first passage 244F1 mv: mass of the valve body 272 ro: rotation radius of the center of gravity of the working fluid existing in the first passage 244F1 rv: rotation radius of the center of gravity of the valve body 272 ω: Rotational speed of casing 240 g: Gravitational acceleration P: Pressure generated by working fluid existing between rotor 220 and casing 240 when slip ratio is 100%, and valve body 272 is in the valve closing direction. Pressure received A: Pressure receiving area of the valve body 272 receiving P k: Spring constant of the compression coil spring 274 X: Natural length of the compression coil spring 274 Xc: Length of the compression coil spring 274 in the valve closed state Xo: In the valve open state Length of compression coil spring 274

As shown in FIG. 4, the valve opening force that acts on the valve body 272 in the valve closing state is m _o (g + r _o ω ² ) due to the mass of the working fluid existing in the small diameter portion of the first passage 244F1. This is the resultant force with m _v (g + r _v ω ² ) due to the mass of the valve body 272. Further, as shown in FIG. 4, the valve closing force acting on the valve body 272 in the valve closed state is PA (caused by the pressure P of the working fluid) and k (XX) caused by the reaction force of the compression coil spring 274. _c ). In order to maintain the valve closing state, the following condition of “valve opening force <valve closing force” needs to be satisfied.

In the valve open state, as shown in FIG. 5, since the discharge passage 244F is opened, m _o (g + r _o ω ² ) due to the mass of the working fluid existing in the first passage 244F1 and the working fluid PA caused by the pressure P disappears. For this reason, as shown in FIG. 6, the valve opening force acting on the valve body 272 is only m _v (g + r _v ω ² ) due to the mass of the valve body 272. Further, the valve closing force acting on the valve body 272 is only k (X−X _o ) due to the reaction force of the compression coil spring 274. In order to maintain the valve opening state, the following condition of “valve opening force ≧ valve closing force” needs to be satisfied.

  Accordingly, the dimensions and mass of each part may be determined as appropriate so that the above conditions (1) and (2) are both satisfied.

  A plurality of cooling fans 170 that increase the amount of air passing through the radiator 160 are attached to the outer peripheral surface of the casing 240.

  According to the fan coupling device 200, when the engine 100 is stopped, the condition (1) is satisfied, so the second valve mechanism 270 is closed. When the second valve mechanism 270 is closed, the communication between the torque transmission chamber 280 and the storage chamber 290 is cut off, so that the working fluid in the storage chamber 290 is torqued by gravity even if the discharge passage 244F is positioned below. There is no supply to the transmission chamber 280. For this reason, immediately after the engine 100 is started, there is no working fluid in the torque transmission chamber 280, so that the cooling fan 170 is prevented from being rotated by the rotation of the pulley 150. And since the accompanying rotation of the cooling fan 170 is suppressed, for example, the quietness of the vehicle at the time of starting the engine can be improved.

  Further, when the engine 100 is operated, the condition (2) is satisfied, so that the second valve mechanism 270 is opened. When the second valve mechanism 270 is opened, the torque transmission chamber 280 and the storage chamber 290 communicate with each other, so that the working fluid in the torque transmission chamber 280 can be discharged to the storage chamber 290. For this reason, the original function of the fan coupling device 200 that transmits the rotational force of the rotor 220 integrated with the drive shaft 210 to the casing 240 can be achieved.

  The fan coupling device 200 excluding the second valve mechanism 270 is not limited to the above configuration, and may be a known fan coupling device. Further, the first valve mechanism 260 is not limited to the above configuration, and may be a known valve mechanism.

100 Engine 150 Pulley 200 Fan coupling device 210 Drive shaft 210C Flange 220 Rotor 240 Casing 242 First casing 244 Second casing 244F Discharge passage 244F1 First passage 244F2 Second passage 244F3 Valve seat 244H Boss portion 250 Plate 250A Valve hole 260 First valve mechanism 262 Bimetal 264 Valve body 266 Rod 270 Second valve mechanism 272 Valve body 274 Compression coil spring (elastic member)
280 Torque transmission chamber 290 Storage chamber

Claims (7)

A rotationally driven drive shaft;
A disc-shaped rotor integrated with the drive shaft;
A casing fixed to the drive shaft so as to be relatively rotatable while accommodating the rotor;
A plate located on a cross section perpendicular to the axial direction of the casing and defining a torque transmission chamber on the rotor side and a storage chamber for the working fluid on the opposite side;
A first valve mechanism for opening and closing a valve hole formed in the outer peripheral portion of the plate according to the ambient temperature;
A second valve mechanism disposed in the middle of a discharge passage formed in an outer peripheral portion of the casing so as to discharge the working fluid from the torque transmission chamber to the storage chamber;
With
The second valve mechanism closes the discharge passage when the rotation speed of the casing is less than a predetermined rotation speed, and opens the discharge passage when the rotation speed of the casing is equal to or higher than the predetermined rotation speed.
Fan coupling device. The discharge passage includes a first passage extending radially outward from an outer edge portion of the storage chamber, and a second passage extending in an orthogonal direction from the first passage and opening in an outer peripheral portion of the torque transmission chamber. Comprising, and
The second valve mechanism includes a valve body disposed so as to be detachable from a valve seat formed in a direction facing the storage chamber in the first passage, and the valve body facing the valve seat. An elastic member for biasing,
The fan coupling device according to claim 1. The elastic member is composed of a compression coil spring.
The fan coupling device according to claim 2. The predetermined rotation speed is less than the rotation speed when the engine is idling.
The fan coupling device according to any one of claims 1 to 3. A flange for fixing to one surface of the pulley driven by the engine is integrated with one end of the drive shaft.
The fan coupling device according to any one of claims 1 to 4. The first valve mechanism closes the valve hole of the plate when the ambient temperature is lower than a predetermined temperature, and opens the valve hole of the plate when the ambient temperature is equal to or higher than the predetermined temperature.
The fan coupling device according to any one of claims 1 to 5. The first valve mechanism includes a spiral bimetal that deforms according to an ambient temperature, a valve body that is detachably attached to the valve hole of the plate, and a boss formed on the casing. A rod that transmits rotation to the valve body instead of the linear movement in the axial direction generated by deformation of the bimetal.
The fan coupling device according to claim 6.