JPH0147605B2 - - Google Patents

Abstract

PURPOSE:To stop operation of a fan positively when the engine temperature is low and to warm up an engine efficiently, by driving a brake member axially by causing change in the shape of a temperature-sensitive member in response to the engine temperature and forcing the brake member onto a brake plate fixed to the outer circumference of a housing to which the fan is attached. CONSTITUTION:When the temperature of cooling water is low, for instance, just after starting of an engine, a temperature-sensitive coil 37 made of a shape memory alloy is expanded and a piston 36 is moved forward, so that a brake member 35 at the top of the piston 36 is forced onto an annular brake plate 33 fixed to the outer circumference of a housing 3 and brakes the housing 3. Subsequently, when the temperature of cooling water becomes higher than the critical temperature of the temperature-sensitive coil 37 as the engine is warmed up gradually, the coil 37 is contracted and the brake member 35 is disengaged from the brake plate 33. Resultantly, a cooling fan 5 is turned at a low speed by the small torque transmitted from a driving shaft 1. Subsequently, when the temperature sensed by a bimetal 13 exceeds its work temperature, the torque transmitted from the driving shaft is increased, so that the cooling fan 5 is turned at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a temperature-sensing fan coupling device used in a cooling fan of an internal combustion engine such as an automobile engine.

For example, in a cooling fan for an automobile engine,
In order to reduce driving force and noise,
Temperature-sensing fan coupling devices that can control the rotation speed according to air temperature are widely used.
FIG. 1 shows an example of the conventional configuration. In detail, 1 is a sleeve-shaped drive shaft equipped with a V-belt pulley 2, and 3 is a bearing 4 attached to the drive shaft 1.
A housing 6 is fixed to the front end of the drive shaft 1 and is housed in the housing 3. A housing 6 is rotatably supported through the housing and has a cooling fan 5 attached to its outer periphery.
It is separated into a storage chamber 8 at the front and a working chamber 9 at the rear in which the rotor 6 is accommodated. The outer peripheral edge of the rotor 6 and the inner wall of the housing 3 opposite thereto have multi-stage labyrinth grooves 1 that engage with each other.
0 and 11 are formed, and the viscous resistance of the working fluid is obtained between the two to act as a fluid coupling. Further, the partition plate 7 is formed with a communication hole 12 that communicates the storage chamber 8 and the working chamber 9, and a valve plate 14 that rotates in conjunction with the spiral bimetal 13 is arranged in front of the communication hole 12. The circulation of the working fluid returned to the storage chamber 8 via the return passage 15 after passing through the labyrinth grooves 10 and 11 is controlled according to the temperature of the air after passing through the radiator (not shown). .

That is, when the air temperature is low, the valve plate 14 closes the communication hole 12 and stops the circulation of the working fluid. Therefore, the labyrinth grooves 10, 1
The amount of working fluid sent into one section is reduced, and therefore the torque transmitted from the rotor 6 to the housing 3 is reduced, causing the fan 5 to rotate at a low speed. On the other hand, when the air temperature is high, the valve plate 14 opens the communication hole 12 and the working fluid flows from the storage chamber 8 to the working chamber 9. Therefore, the labyrinth grooves 10, 1
A sufficient amount of working fluid is supplied to one portion, so that the torque transmitted from the rotor 6 to the housing 3 increases, and the fan 5 rotates at high speed.

The drive shaft 1 is fixed to the front end of a pump shaft 17 which has a water pump inverter 16 at its rear end, and is connected to the water pump 19 of the engine body 18.
A bearing 21 is attached to a bearing sleeve 20 provided on the front side.
The pump shaft 17 is rotatably supported through the pump shaft (for example, Sankaido Co., Ltd.
"Automotive Engineering Complete Book Volume 4 Gasoline Engine" published in Monthly
(See page 363).

However, in the conventional configuration as described above, even when the valve plate 14 closes the flow hole 12, some amount of torque transmission due to viscosity and friction of the bearing 4 still remain. , the housing 3, ie, the cooling fan 5, is not completely stopped. Therefore, there is a problem in that the engine is overcooled by the fan air when the engine is cold started, leading to deterioration in warm-up characteristics and deterioration in the performance of the heater that uses cooling water.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a fan coupling device that completely stops the rotation of the housing when the engine is cold and has not been warmed up yet. The purpose is to improve engine warm-up characteristics and heater performance.

That is, the fan coupling device for an internal combustion engine according to the present invention includes a housing that is rotatably supported on a drive shaft and to which a fan is attached, an annular brake plate provided on the outer periphery of the housing, and an annular brake plate provided on the outer periphery of the housing. A brake element that is disposed facing each other and can be moved toward and away from the brake plate by changing the shape of a temperature-sensitive member made of a shape memory alloy; The heating mechanism is equipped with a heating mechanism that causes a change in temperature.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 2 shows a fan coupling device according to the present invention. It is broadly divided into a braking mechanism 32 that prevents rotation of the motor. Here, the coupling body 31
Since this embodiment is basically the same as the coupling device shown in FIG. 1 described above, the same parts are given the same reference numerals and detailed explanation will be omitted.

The braking mechanism 32 includes an annular braking plate 33 fixed to the outer periphery of the housing 3 of the coupling body 31.
and a substantially cylindrical body 34 fixed to the engine main body 18, and slidably supported by this body 34,
and a piston 36 having a brake member 35 at its tip;
The temperature sensing coil 37 is housed in the body 34 and is made of a shape memory alloy and has both ends locked to the bottom of the body 34 and the bottom of the piston 36, respectively, and is sealed with an O-ring 38. A portion of engine cooling water is introduced into the heated body 34 as a heating mechanism through a cooling water inlet 34a and an outlet 34b. The temperature sensing coil 37 is in a contracted state at a high temperature after reaching a predetermined transformation temperature.
It has a shape memorized so that it will be in an elongated state at low temperatures, and its transformation temperature is lower than the operating temperature of the bimetal 13 of the coupling body 31, and the temperature at which the engine is considered to have warmed up (for example, about 60°C).
before and after).

That is, when the cooling water temperature is low, such as after starting the engine, the temperature-sensing coil 37 is extended, the piston 36 protrudes, and the brake element 35 at the tip of the piston 36, which is disposed opposite to the brake plate 33, touches the brake plate 33.
press against. The housing 3 is braked by the frictional resistance caused by the pressure contact between the two, and since only a very small torque is being transmitted to the housing 3 at this time due to the control of the working fluid as described above, the housing 3 That is, the cooling fan 5 completely stops.

On the other hand, when the engine warms up and the cooling water temperature exceeds the transformation temperature of the temperature-sensing coil 37, the temperature-sensing coil 37 becomes contracted and the brake element 35 moves toward the brake plate 3.
Move away from 3. As a result, the housing 3 is released, and the cooling fan 5 starts rotating at a relatively low rotation speed due to the slight torque transmitted from the drive shaft 1 side.

Thereafter, when the temperature sensed by the bimetal 13 exceeds its operating temperature as the temperature of the cooling water flowing through the radiator (not shown) increases, the transmitted torque is increased and the cooling fan 5 is Rotate at high speed.

According to the above configuration, when the engine is not warmed up as detected from the cooling water temperature, the rotation of the cooling fan 5 is completely stopped, which speeds up the start of warm-up and allows the engine to utilize the cooling water. Heater performance improves.

Next, FIG. 3 shows a different embodiment of the braking mechanism 32, which is constructed so that an opening 39 is provided in the body 34 as a heating mechanism for a temperature sensing coil 37 to introduce the ambient temperature near the engine. .

Further, in the embodiment shown in FIG. 4, the temperature of the engine is detected at a location other than the braking mechanism 32, and a temperature switch 41 for detecting the cooling water temperature, lubricating oil temperature, ambient temperature, etc. The thermosensing coil 37 is provided at a suitable position, and is configured to energize the thermosensing coil 37 using a battery 42 as a heating mechanism, thereby causing the thermosensing coil 37 itself to generate heat. That is, when the engine is cold, the temperature switch 41 is turned off and the temperature sensing coil 37 is in an extended state, and when the engine is warmed up, the temperature switch 41 is turned on and the temperature sensing coil 37 itself generates heat, thereby reducing the temperature. change in state. In this way, similarly to each of the embodiments described above, braking and release are switched by the temperature switch 41. In the case of this embodiment, the temperature-sensitive coil 37 is set so that it is in an expanded state when energized (at high temperature) and contracted when not energized (at low temperature), and the temperature switch 41 is Exactly the same operation can be achieved by configuring the switch to be turned on when the engine is not warmed up and turned off when warm-up is completed.

Next, in the embodiment shown in FIGS. 5 and 6, lug-shaped teeth 33a are formed on the brake plate 33, and the brake element 35' is meshed with the latch-shaped teeth 33a. Further, in this embodiment, the brake member 35' is formed as a part of a temperature-sensitive member 43, and specifically, the temperature-sensitive member 43 is formed in the shape of a flat band from a shape memory alloy. Both ends are slidably supported by holders 44, and when the temperature is below the transformation temperature, the central part protrudes into a substantially triangular shape as a brake 35' as shown by the solid line in FIG. At high temperatures, each shape is memorized so that it becomes flat as shown by the dotted line. Therefore, when the unwarmed state of the engine is detected based on the ambient temperature, the brake plate 33 engages with the teeth 33a of the brake plate 33 to reliably prevent its rotation.

As is clear from the above explanation, in the fan coupling device for an internal combustion engine according to the present invention,
The rotation of the cooling fan is completely stopped when the engine is not warmed up, thereby preventing unnecessary cooling, and improving the warm-up characteristics of the engine and the performance of the heater using cooling water.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional fan coupling device, FIG. 2 is a cross-sectional view of a fan coupling device according to the present invention, and FIGS. 3, 4, and 5 each show different embodiments of the braking mechanism. A sectional view of the main parts shown,
FIG. 6 is a view taken along arrow A in FIG. 1... Drive shaft, 3... Housing, 4... Bearing, 5... Cooling fan, 6... Rotor, 7... Partition plate,
8... Storage chamber, 9... Working chamber, 10, 11... Labyrinth groove, 12... Distribution hole, 13... Bimetal, 14...
Valve plate, 17... Pump shaft, 18... Engine body, 31... Coupling body, 32... Braking mechanism,
33... Brake plate, 34... Body, 35, 35'... Brake element, 37... Temperature sensing coil, 41... Temperature switch,
43...Temperature-sensitive member, 44...Holder.

Claims (1)

[Claims] 1. A housing rotatably supported by a drive shaft and to which a fan is attached, an annular brake plate provided on the outer periphery of the housing, and a temperature-sensitive member made of a shape memory alloy and arranged opposite to the brake plate. It comprises a brake that can move toward and away from the brake plate by changing its shape, and a heating mechanism that causes the temperature-sensitive member to change its shape in a predetermined manner depending on whether the engine is warmed up or not warmed up. Fan coupling device for internal combustion engines.