TECHNICAL FIELD

The present invention relates to a thermostat device which is disposed in a circulation channel for circulating a coolant between an internal combustion engine (hereinafter also referred to as engine) of automobiles, for example, and a radiator and variably controls the temperature of the coolant.

BACKGROUND ART

A thermostat device is provided with a thermo-sensitive element incorporating a thermal expansion body (wax) which expands or contracts due to the temperature change of a coolant flowing through the inside of a circulation channel between an engine and a radiator. The thermostat device functions to keep the coolant at a predetermined temperature by opening or closing a control valve in response to the volume changes due to the expansion and contraction of the thermal expansion body.

That is, the thermo-sensitive element filled with a thermal expansion body and a thermal-operating unit having the control valve body is housed in a housing and disposed at the entrance, for example, of the coolant passage of the engine. The coolant circulates by way of a by-pass passage without going through the radiator when the temperature of the coolant is low and the control valve is closed.

When the temperature of the coolant rises, the valve opens to allow the coolant to circulate through the radiator. With this, the thermal-operating unit keeps the temperature of the coolant, which flows through a water jacket as a cooling passage of the engine, in a predetermined state.

Thermostat devices of this kind are conventionally modified and proposed in various ways. The present applicant has proposed a thermal-operating unit including a thermo-sensitive element and a control valve therein and a thermostat device housing a temperature sensor detecting the temperature of the coolant. This proposal is disclosed in a PTL 1.

CITATION LIST

Patent Literature

PTL1: JP-A-2011-179480

With the use of the above-described thermostat device, the temperature sensor in the housing of the thermostat device can detect the temperature of the coolant entering the engine with high precision. The utilization of the temperature information allows a contribution to further improvement of fuel consumption of the engine.

Since construction is employed in which the temperature sensor is detachably attached along the axial direction in a supporting tube formed in the housing, the operation to slightly draw the temperature sensor along the axial direction allows breaking the tight-sealing of the housing. Thus, practical effects are available such as a degassing function when the coolant is filled into the circulation passage or a function as a drain cock to discharge the coolant from the circulation passage at a time of exchange of coolant.

SUMMARY OF INVENTION

Technical Problem

In the thermostat device described above, when a thermal-operating unit including a thermo-sensitive element and a control valve is installed into the housing, some additional members are required such as coil spring biasing the control valve to be in a closed state and a spring receiving frame to receive one end of the coil spring.

Of these, in particular, the spring receiving frame and frame support formed in the housing may impede the flow of the coolant flowing in the housing because the faces of the spring receiving frame or the frame support are placed in a direction perpendicular to the coolant passage in the housing.

This may cause turbulence or stagnation of coolant and increase pressure loss in the passage. Accordingly, other problem may arise including cost rise due to the need for the enlargement in size of a water pump disposed in the coolant passage.

The present invention aims at providing a thermostat device capable of reducing flow resistance caused by the spring receiving frame and the frame support therefor formed in the housing and reducing pressure loss in the passage.

Solution to Problem

A thermostat device according to the present invention includes a thermal-operating unit accommodated in a housing, which is disposed in a circulation passage for circulation of a coolant between an internal combustion engine and a radiator, controls the temperature of the coolant supplied to the internal combustion engine; the thermal-operating unit that is provided with a thermo-sensitive element incorporating a thermal expansion body that expands or contracts corresponding to the coolant temperature change, a control valve that opens or closes the passage in the housing based on the expansion or contraction of the thermal expansion body in the thermo-sensitive element, a spring biasing so as to close the control valve, and a spring receiving frame receiving one end of the spring, wherein the thermal-operating unit is incorporated by a constitution that a locking portion formed on the spring receiving frame is locked to a frame support formed in the passage of the housing, and a rectifier is disposed at the upper stream of the coolant flow at the frame support to prevent a collision of coolant flow between the frame support and the spring receiving frame by bypassing the coolant flow forwarding the frame support and the spring receiving frame.

In this case, it is desirable to configure that the rectifier is disposed to protrude from the wall of the housing along the passage of the housing, and a central portion of the rectifier is located on an upstream side of the coolant flow and, both leg portions thereof are located at the downstream of the coolant flow compared to the central portion.

Another configuration is preferably employed that the rectifier is disposed to protrude from the wall of the housing along the inside of the passage of the housing with one end thereof located upstream of the coolant flow and the other end located downstream of the coolant flow; such a bar-shaped rectifier is continuously formed to be diagonal to the flow direction of the coolant.

A coil spring is used as a spring; the diameter of a first end thereof is gradually reduced toward a second end to form a cone shape preferably. The spring is disposed such that the larger diameter portion of the spring abuts on the control valve and the smaller diameter thereof abuts on the spring receiving frame.

In addition, the spring receiving frame has locking portions to be locked to the frame support. The locking portions are provided on both sides in the longitudinal direction of the spring receiving frame and formed to a rectangular shape. The width of the spring-receiving frame at the position on which the second end with a small diameter of the coil spring abuts is desirably formed substantially the same as the width of the locking portion of the spring receiving frame.

Advantageous Effects of Invention

In the thermostat device according to the present invention, a rectifier is disposed on an upstream side of the coolant flow at the frame support formed in the housing so that collision of coolant flow against the frame support and the spring receiving frame is avoided by detouring the flow passage of the coolant heading to the frame support and the spring receiving frame.

In a preferable embodiment of the rectifier, since a central portion of the rectifier is located on an upstream side of the coolant flow and both leg portions thereof are located at the downstream of the coolant flow compared to the central portion, the increase of flow resistance due to the frame support and the spring receiving frame supported thereby can be suppressed.

In another preferable embodiment of the rectifier, the rectifier is disposed protruding along the inside of the passage of the housing with one end thereof located upstream of the coolant flow and the other end located downstream of the coolant flow; the bar-shaped rectifier is continuously formed to be diagonal to the flow direction of the coolant.

Thus, the increase of flow resistance due to the frame support and the spring receiving frame supported thereby can be suppressed, and the flow of the coolant in the housing can be smoothed.

Further, a coil spring is used as a spring biasing to close the control valve; the diameter of one end thereof (first end) is gradually reduced toward the other end (second end) to form a cone shape. The spring receiving frame is configured to be in contact with the reduced-diameter portion of the spring. In addition, a structure is employed that the width of the spring receiving frame at the position with which the second end with a small diameter of the coil spring is in contact is desirably formed to be substantially the same as the width of the locking portion of the spring receiving frame. This contributes to allowing a further size reduction of the spring receiving frame and a further reduction of flow resistance due to the spring receiving frame in the housing.

Therefore, a thermostat device can be provided in which the coolant flow in the housing is smoothed more and the pressure loss within the circulation passage can be reduced, owing to the action of the rectifier and the employment of the spring receiving frame with a narrow width.

