JPS6188028A - Temperature sensing fan clutch for car - Google Patents

Abstract

PURPOSE:To ensure the operation of a clutch by energizing a cam member, with a clutch member directed toward a rotary member or in a direction separated from said rotary member, by means of a coil form shape-remembering alloy member. CONSTITUTION:An annular clutch member 8 is fitted over the outer periphery of the small diameter part 5b of a boss 5 adjacent to a pulley 2, axially slidably and coaxially rotatably with respect to the boss 5, via a slide bearing 9. On the mutually opposite surfaces of the boss 5 and the clutch member 8, plural boat-shaped recesses 5a, 8a are provided respectively being opposite to each other, and a steel ball 10 is housed in each pair of the recesses 5a, 8a. And, the boss 5 and the clutch member 8 are connected by means of a tensile-coil form shape-remembering alloy member 13 and tensile coil spring 16 whose direction of tension is opposite to that of the member 13, on their outer peripheral parts.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a temperature-sensitive fan clutch for an automobile that uses a shape memory alloy.

<Prior art> When the engine is warmed up or when the car is running at high speed, there is no or little need to cool the engine, so driving the cooling fan despite this causes power loss and warm-up. This may cause a delay in the start-up of the heater, which uses the engine's cooling water as its heat source, etc. Therefore, it is preferable to stop the function of the cooling fan when there is no need to cool the engine.

An electric type fan is suitable because it is easy to control, but if the current used is limited to 211, as in cars, it may not always be possible to ensure sufficient air flow. . Temperature-sensitive cooling fans in which a fluid coupling is controlled by a temperature-sensitive element such as a bimetal are also known.
Due to the viscosity of the cooling fan used as the engine fluid, the cooling fan may continue to rotate at a fairly high speed even when it is originally intended to be stopped. Not only inviting, but also @machine time-
It is not possible to shorten the time by 1 minute, and in particular, the effect of accelerating the operation of the heater is not sufficient.

Various temperature-sensitive cooling fans using shape-memory alloys that have I-geometry functions as both a temperature-sensing element and an actuator are known, but their structures tend to be relatively complex and their control characteristics are not necessarily suitable.

For example, in the temperature-sensitive cooling fan proposed in Japanese Patent Application Laid-Open No. 55-57729, not only the structure is relatively complicated, but also the strain rate of the shape memory alloy is large. The biasing force of the shape memory alloy decreases due to the stress-induced martensitic transformation, making it difficult to obtain the desired control action. Furthermore, since it utilizes the bending deformation of a flat shape memory alloy, it is difficult for the shape memory alloy to return to its flat state completely at low temperatures, making it difficult to release the clutch stably at low temperatures. There are possible cases.

<Problems to be Solved by the Invention> In view of these drawbacks of the prior art, the main object of the present invention is to provide a moisture-sensitive fan clutch for privately-owned vehicles that has a simple structure and can operate reliably. It's about doing. .

<Means for Solving the Problems> According to the present invention, such an object is to provide a boss to which a fin blade is attached, and a boss that is movable relative to the boss along its axial direction. and a clutch member rotatable integrally with the boss; a member facing the clutch member and rotating integrally with the fan drive shaft; and/or a clutch facing fixed to the clutch member; a coiled shape memory alloy member capable of biasing the cam member in a direction in which the clutch member is directed toward the rotating member or away from the rotating member; ,
This is achieved by providing a temperature-sensitive fan clutch characterized by having a return spring member that biases the clutch member in a direction opposite to the biasing direction of the coiled shape memory alloy member.

According to the above-mentioned temperature-sensitive fan clutch, its structure is simple, and since it uses a coiled shape memory alloy member, its stroke can be made sufficiently large without increasing the strain rate. I can do it. In particular, its structure is suitable for miniaturization, and therefore the inertial mass of the cooling fan clutch can be reduced, improving response and durability of the clutch.

<Embodiments> Preferred embodiments of the present invention will now be described in detail with reference to the attached notes.

FIGS. 1 and 2 show a first embodiment of a wet fan crape according to the present invention. A pulley 2 for power transmission is fixed to a drive shaft 1 of a water pump (not shown) via a half-moon key 3. A substantially disc-shaped boss 5 is pivotally supported on the drive @ 1 via two ball bearings 4, and a required number of blades (not shown) are screwed onto the boss by blade bolts 6. ball bearing 4
is positioned by the mounting boss 2a of the pulley 2 and the bearing retainer 7 screwed onto the free end of the drive shaft 1, and as a result, the axial position of the boss 5 is determined.

The bearing holder 7 is provided with radial fins 7a and has a labyrinth-like gap from the outside air to the bearing, so as to exhibit a dust-proofing effect.

A portion of the boss 5 adjacent to the pulley 2 forms a small diameter portion 5a, and an annular clutch member 8 is attached to the outer periphery of the small diameter portion 5a via a slide bearing 9, and is slidable along the axial direction with respect to the boss 5. and is fitted so as to be rotatable coaxially. A plurality of powder-like recesses 5a and 8a are provided on opposite surfaces of the boss 5 and the clutch member 8, respectively, so as to face each other, and a steel ball is inserted into the cavity defined by these recesses. 10 has been accepted.

Further, on the outer circumferential surfaces of the boss 5 and the clutch member 8, there are two scale grooves 11 and 12 that are sloped in opposite directions with respect to the axial direction.
and 14.15 are recessed across the boss 5 and the clutch member 8. A bottle is provided protruding from the end of the boss 5 side and the end of the clutch member 8 side of these plates, and between the bottles provided at each end of the plate 11 and 12 which are inclined in one direction with respect to the axial direction. A shape memory alloy member 13 in the form of a tension coil spring is tensioned, and a tension coil spring 16 is tensioned between the pins provided at each end of the groove 14 and 15 inclined in the other direction with respect to the axial direction. has been done.

Next, the operation of this embodiment will be explained.

When cold, the tensile force of the coil spring 16 is dominant over the tensile force of the shape memory alloy member 13, so the boss 5 and the clutch member 8 are close to each other as shown in FIGS. 1 and 2. Since the clutch facing 17 fixed to the clutch member 8 is separated from the engagement surface provided on the pulley 2, the boss 5 is in a state where it can freely rotate with respect to the drive @1 by the action of the ball bearing 4. be. Therefore, when the airflow is blown toward the fan as when the car is running, the blades attached to the boss 5 rotate like a windmill, and the blades attached to the boss 5 rotate like a windmill. Do not add any nine direction.

@la#a of the engine, as the ambient temperature rises, the coiled shape memory alloy member 13 undergoes ausbunite transformation and its tensile force increases, and the coiled shape memory alloy member 13 resists the tensile force of the coil spring 16. The alloy member 13 will be compressed. Then, a relative rotation occurs between the boss 5 and the clutch member 8 in the direction indicated by the arrow a in FIG.
The boss 5 and the clutch member 8 are driven in a direction to separate them from each other as indicated by the arrows. Therefore, the clutch member 8 and the clutch facing 17 fixed thereto are pressed toward the engagement surface of the pulley 2, and the force that rotationally drives the pulley 2 causes the clutch member 8 and the boss 5 to rotate integrally. As a result, the blade screwed onto the boss 5 rotates to generate the required cooling air.

When the engine room temperature drops again, the coiled shape memory alloy member 13 undergoes martensitic transformation,
Since the tensile force decreases by about 60%, the biasing force of the coil spring 16 becomes dominant again, and the boss 5 and the clutch member 8 perform relative rotation in the opposite direction to the above, and the boss 5 due to the steel ball 10 The driving force that attempts to separate the clutch member 8 from the clutch member 8 is lost, and the clutch member 8 is pulled back toward the boss 5 by the combined restoring force of the shape memory alloy member 13 and the coil spring 16, and the clutch facing 17 and The frictional engagement with the pulley 2 is released.

FIG. 3 shows a second embodiment of the present invention, in which the drive shaft 1
The boss 5', which is pivotally supported via a ball bearing 4, is
The surface facing the pulley 2 forms a slope 5 a J , and the clutch member 8' is mounted so as to be able to move along the slope 5 a l while being guided by a rond 9'. A shape memory alloy member 13' in the form of a compression coil spring and a normal compression coil spring 16' are wound around the guide rod 9' on the upper and lower sides of the clutch member 8', respectively. 5a'. In order to ensure the required frictional contact area, such slope 5aI and clutch member 8'
For example, four numbers may be arranged along the circumference IJ direction of the boss 5'.

At low temperatures, the biasing force of the compression coil spring 16' is weak, so that the clutch facing 17 fixed to the clutch member 8' and the engagement surface of the pulley 2, as shown in FIG. The hub 5' and the blade fixed to the hub are in a free state. As the engine warms up and the ambient temperature rises, the biasing force of the shape memory alloy member 13' becomes dominant, and the clutch member 8' is pressed against the pulley 2 via the clutch facing 17.
The driving force transmitted to the pulley 2 is transmitted to the hub 5', causing the blade to rotate.

FIG. 4 shows a third embodiment based on the present invention, in which a small diameter portion 5b" provided on the pulley 2 side of a disc-shaped hub 5"
An annular clutch member 8'' is fitted so as to be slidable along the axial direction.The clutch member 8'' is restored by a pressing spring 16'' from the side to which the clutch facing 17 is fixed, as shown in FIG. It is biased towards the left direction.

A plurality of radial grooves 8a'' are cut in the surface of the clutch member 8'' opposite to the surface to which the clutch facing 17 is fixed, and the hub 5 is connected to the bottom surface of each groove by a pin 18.
One end of the V-supported cam member 10'' is in contact with the hub 5'', and a shape memory alloy member 13'' in the form of a tension coil spring is stretched between the other end of the cam member 10'' and the hub 5''. .

In this embodiment as well, when the clutch facing 17 is separated from the engagement surface of the pulley 2 because the biasing force of the pressing spring 16'' is dominant when it is cold, the clutch facing 17 retains its shape when the ambient temperature rises. The tensile force of the alloy part 013″ becomes dominant,
The clutch member 8'' is pushed out toward the pulley 2 by the action of the cam member 10'', and the clutch member 8'' is pushed against the engagement surface of the pulley 2 via the clutch facing 17.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above. For example, the shape memory alloy may be replaced with a return spring, and the stress change due to the temperature change of the shape memory alloy may be made to be opposite to that of the above embodiment.

Effect> As described above, according to the present invention, the use of a coiled shape memory alloy member makes it possible to obtain the required stroke without increasing the strain rate of the shape memory alloy so much that stress-induced martensite Sufficient driving force can be obtained with the shape memory alloy without transformation. In addition, since the structure is simple, the overall weight can be reduced, and the load on the clutch can be reduced, making it possible to improve the durability of the fan clutch and reduce its manufacturing cost. can. Furthermore, since the clutch can be completely disengaged at low m*, it is possible to effectively prevent power wastage and minimize wear on the clutch facing.

[Brief explanation of drawings]

FIG. 1 is a side view showing the upper half of a first embodiment of the Ω-type fan assembly according to the present invention. FIG. 2 is an enlarged partial sectional view taken along the line ■--■ in FIG. 1. FIG. 3 is an eleventh sectional view showing a second embodiment of the present invention. FIG. 4 is a longitudinal sectional view showing a third embodiment of the present invention. 1-... Drive shaft 2... Pulley 2a... Pulley mounting hub 3... Half-moon key 4... Ball bearing 5.5', 5''... Hub 5a... Recess
5b, 5b"...Small diameter part 6...Blade bolt
7...Bearing retainer 7a...Radial fin 8.8', 8''...Clutch member 8a, 8a''...Recess 9...Slide bearing 9'...Guide Rond 10...Steel Ball 10″...
Cam member 11.12...Groove 13.13', 13"
...Shape memory alloy member 14.15...Groove 16
...Tension coil spring 16'...Compression coil spring 16''...Press spring 17...Clutch facing 18...Pin

Claims (1)

[Claims] A temperature-sensitive fan clutch for an automobile using a shape memory alloy, comprising a boss to which a fan blade is attached, and a boss that is movable relative to the boss along its axial direction. and a clutch member that is rotatable integrally with the boss; a member that faces the clutch member and rotates integrally with the fan drive shaft; and/or a clutch facing that is fixed to the clutch member; a cam member that can be driven toward the rotating member along the rotational member; and a coiled shape memory alloy member that can bias the cam member in a direction in which the clutch member is directed toward the rotating member or away from the rotating member. and a return spring member that biases the clutch member in a direction opposite to the biasing direction of the coiled shape memory alloy member.