JPS6345487B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling water temperature control device for an internal combustion engine, and particularly to a device for controlling a valve opening temperature according to the load of the internal combustion engine.

Various cooling water temperature control devices that control valve opening temperature according to the load of an internal combustion engine have been proposed in the past. FIG. 1 shows this type of control device disclosed in Japanese Utility Model Application Publication No. 54-142722, in which a wax-type thermostat 3 is installed between a water outlet 1 provided in the engine body and a water outlet housing 2. is being held. This thermostat 3 has a container-shaped temperature sensing part 4 and a piston 5 that slides up and down inside the temperature sensing part 4. The temperature sensing part 4 is filled with solid wax and elastic rubber. The head of the piston 5 is configured such that upward biasing force is suppressed by the operation of a control piece 6, which will be described later. Therefore, when the temperature of the engine cooling water rises and the wax melts and expands, the resulting pressure will cause the temperature sensing portion 4 to move as long as the head of the piston 5 is restrained by the control piece 6. is pushed downward. Reference numeral 7 denotes a valve member provided on the outside of the temperature sensing part 4. When the thermostat 3 is not activated, the valve member 7 is biased toward the fixed valve seat 9 by the spring force of the spring 8, thereby cooling the thermostat. water passage 1
0 is closed.

The control piece 6 is a diaphragm device 11 for actuating the control piece.
The diaphragm device 11 is attached to the water outlet housing 2 via a seal member 13. The upper chamber 14 of the diaphragm device, which is divided into upper and lower parts by the diaphragm 12, is a negative pressure chamber,
The lower chamber 15 communicates with the atmosphere. The negative pressure chamber 14 is connected to a negative pressure source such as an intake manifold (not shown) via a negative pressure delay valve 16, and the intake negative pressure is applied to the negative pressure chamber 1 according to engine load fluctuations.
4.

Reference numeral 17 denotes a stopper provided at the upper part of the negative pressure chamber 14, which restricts the upward movement of the control end 6A when it slides up and down along the inner surface of the guide member 18 of the thermostat 3. . 19 is a spring provided in the negative pressure chamber 14, and when the negative pressure introduced into the negative pressure chamber becomes small and approaches atmospheric pressure, the spring force causes the diaphragm 12 and the control piece 6 to move as shown in the figure. Return to position.

To explain the operation of the cooling water temperature control device configured in this way, first, when the load is high, the suction negative pressure in the intake manifold is relatively small and the diaphragm 12 is biased downward as shown in the figure. The piece 6 remains approximately in the position shown in the figure. Therefore, when the cooling water temperature rises and the wax in the temperature sensing part 4 melts and expands, the free end of the head of the piston 5 immediately comes into contact with the end 6A of the control piece 6, causing the attachment to try to extend upward. The force is restrained by the spring force of spring 19. Therefore, the temperature sensing part 4 of the thermostat 3 is connected to the spring 8.
The valve member 7 provided around the temperature sensing part 4 is pulled away from the valve seat 9 and opened. In other words, when the engine is under high load, the thermostat 3 opens the valve at a relatively early stage when the temperature of the cooling water rises, so the temperature of the cooling water at the time when the valve starts to open is relatively low. , for example, is maintained at around 70℃.

Next, when the engine is under low load, a relatively large suction negative pressure is introduced into the negative pressure chamber 14, so that the control piece 6 is pulled upward together with the diaphragm 12 against the spring force of the spring 19. Therefore, when the wax in the temperature sensing part 4 expands due to an increase in the cooling water temperature, the piston 5 first begins to extend upward, but since the end 6A of the control piece 6 is pulled upward, the piston 5 expands. Piston 5 continues to extend until its free end abuts end 6A. After the piston 5 comes into contact with the control piece 6, the valve is opened by the thermostat 3 in the same manner as described above. In other words, the temperature is kept relatively high compared to when the load is high.

However, in such a conventional cooling water temperature control device for an internal combustion engine, the holding spring 19 of the control piece 6 of the diaphragm device 11 and the temperature sensing portion 4 provided on the thermostat 3 are connected to the closed state of the valve. The spring 8 that maintains the control piece 6 is placed in such a state that its spring force influences each other when the end 6A of the control piece 6 is in contact with the free end of the piston 5. Moreover, in the state before the control device is activated, a gap is provided between the free end of the piston 5 of the thermostat 3 and the end portion 6A of the control piece 6, and the temperature sensing portion 4 is simply It is held in the position shown in the figure only by the spring force of spring 8.

For this reason, since the cooling water temperature control changes depending on the balance of the springs 19 and 8, it is difficult to set the spring forces of these springs 8 and 19. HC) was difficult to reduce. Further, the adjustment of the clearance between the control piece 6 and the piston 5, the setting for balancing the spring forces of the springs 8 and 19, etc. are related to the setting of the valve opening timing in the thermostat 3. It is difficult to set the initial valve opening temperature in step 3.

Further, the spring 19 maintains a compressed state due to the negative pressure in the negative pressure chamber 14, and while maintaining this state, the spring 8 is pressed down when the container part 4 is pushed down via the control piece 6. Since the spring 19 is compressed, the spring force of the spring 19 needs to be sufficiently stronger than the spring force of the spring 8. For this purpose, the diaphragm 12
The diaphragm device 11 must also be strong enough to withstand the spring force of the spring 19, which requires a large diaphragm device 11, which increases the cost of the control device.

In view of the above-mentioned points, an object of the present invention is to attach and fix a thermostat shaft on which a temperature sensing part slides to a support member, and to attach a thermostat valve to a movable valve seat that takes a position corresponding to the load of the engine. A movable valve seat movement control device such as a diaphragm device that closes the cooling water passage by bringing the movable valve seat into contact and prevents the force that moves the movable valve seat from opposing the force that acts to close the thermostatic valve. An object of the present invention is to provide a cooling water temperature control device for an internal combustion engine, which is miniaturized and allows easy setting and adjustment of the initial valve opening temperature.

The present invention will be explained in detail below based on the drawings.

In the following, the same reference numerals will be used for the same parts as in FIG. FIG. 2 shows an example of the device of the present invention, in which 20 is a thermostat housing provided in the cooling water passage 10, and 21 is a movable thermostat housing that is slidable along the inner surface of the cylindrical portion 20A of the thermostat housing 20. It is a valve seat. The thermostatic valve 22 facing the movable valve seat 21 has a head 4
It is fitted into the thermostat temperature sensing part 4 having a bulge in the shape of A so as to be able to slide downward, and the spring force of the compression spring 23 provided between the thermostat valve 22 and the housing cylindrical part 20A. The valve 22 is brought into contact with the valve seat 21 by this.

24 is a valve seat drive shaft formed integrally with the movable valve seat 21, and the end of this valve seat drive shaft 24 is attached to a valve seat movement control device, for example, the diaphragm 12 of the diaphragm device 11. 25 is a stopper provided protruding from the negative pressure chamber 14 of the diaphragm device 11 to restrict the downward movement of the drive shaft 24;
19 is an elastic support member, for example a spring; 26
27 is a negative pressure pipe that guides negative pressure from the intake manifold (not shown) side to the negative pressure chamber 14, and 27 is a cooling water bypass passage.

When the cooling water temperature control device is not operating, that is, when the internal combustion engine is stopped and the cooling water temperature is relatively low and the wax in the temperature sensing section 4 has not melted, the state shown in FIG. As shown in FIG. 2, the upper surface of the movable valve seat 21 is brought into contact with the locking portion 20B of the housing 20 via the diaphragm 12 and the drive shaft 24 due to the spring force of the spring 19. In this state, the thermostat valve 22 is pushed up by the spring force of the spring 23 and kept in the closed state, and at the same time the thermostat valve 22 whose end is attached and fixed to the thermostat housing 20 is closed. As shown in this figure, the shaft 28 and the temperature sensing section 4 are connected to each other, so that the temperature sensing section 4 is
is kept in contact with.

Next, the operation of the cooling water temperature control device configured as described above will be explained.

First, when the engine is in a high-load operating region, the suction negative pressure is relatively small and close to atmospheric pressure, so the diaphragm 12 is hardly drawn into the negative pressure chamber 14, and the diaphragm 12 is hardly sucked into the negative pressure chamber 14, as shown in FIG. Therefore, the movable valve seat 21 is also maintained with its upper surface in contact with the locking portion 20B of the housing 20.

Therefore, when the temperature of the cooling water rises and the wax sealed in the temperature sensing part 4 begins to melt, the thermostat shaft 28 moves toward the thermostat housing 20.
Since the temperature sensing part 4 is held in a state where it is held in the position shown in FIG. Due to this operation of the temperature sensing part 4, the thermostat valve 22 fitted around the temperature sensing part 4 is pulled down together with the temperature sensing part 4 against the spring force of the spring 23, and is released from the valve seat 21. and open the valve. By opening this valve, cooling water is sent to a radiator (not shown) and cooling is started.

Note that the spring 19 of the diaphragm 11 only needs to have a relatively small spring force to bring the movable valve seat 21 into contact with the locking portion 20B of the housing 20 and maintain this state, and when the valve is opened, Spring 23
is not affected by the spring force of

Next, when the engine is in a low-load operating region, the suction negative pressure is relatively large, so the diaphragm 12 is attracted toward the negative pressure chamber 14 against the spring force of the spring 19, causing the drive shaft 24 to move downward. reduce. Therefore, the movable valve seat 21 is pulled down along the inner surface of the cylindrical portion 20A of the thermostat housing 20, and the thermostat valve 22, which is kept in the closed state by contacting the valve seat 21, remains in the closed state. It is pulled down along the outer peripheral surface of the temperature sensing part 4. Therefore, in this state, the temperature of the cooling water in the cooling water passage 10 increases without being led to the radiator (not shown).

Here, in the temperature sensing part 4, as the water temperature rises, the wax begins to melt and expand, so the temperature sensing part 4 begins to descend along the inner circumferential surface of the thermostat valve 22, as described above, and eventually its temperature increases. The head portion 4A of the temperature sensing portion 4 comes into contact with the tapered portion 22A of the thermostat valve 22. After that, the temperature sensing part 4 pushes down this thermostat valve 22 against the spring force of the spring 23,
Valve 22 is released from movable valve seat 21 and cooling water is guided to the radiator. That is, when the load is low, the opening temperature of the thermostat valve 22 is higher than when the load is high, and the cooling water temperature can be maintained at a relatively high temperature.

As is clear from the above description, the spring 19 for holding the diaphragm of the diaphragm device 11 only needs to have a spring force sufficient to hold the movable valve seat 21 in a required position via the drive shaft 24. The spring force of the spring 23 holding the thermostatic valve 22 has no effect on the spring 19, and the two springs 23 and 19 are provided with mutually independent functions. Therefore, when setting the spring force of the spring 19, it is sufficient to consider the assumed negative pressure at a low load and the strength of the diaphragm 12, and there is no need to use a large spring as in the conventional case.

Furthermore, since the end of the thermostat shaft 28 is fixed, a general-purpose product can be used, and the influence of the thermostat valve retaining spring 23 does not affect the diaphragm device 11 when the valve is opened. Since there is no temperature control, it is easy to adjust the set temperature when the valve is initially opened.

As explained above, according to the present invention, a movable valve seat whose position changes up and down depending on the load;
A thermostat temperature-sensing part with a thermostat shaft attached to a support provided in the cooling water passage, and a thermostat valve that slides along the outer circumferential surface of the temperature-sensing part are provided, and this valve and a movable valve are provided. The cooling water passage is opened and closed between the temperature sensor and the movable valve seat, and the relative positions of the temperature sensing part and the movable valve seat and valve are changed to change the timing at which the cooling water passage is opened, thereby controlling the cooling water temperature. Since the force that moves the movable valve seat and the force that acts to close the thermostatic valve do not oppose each other, the cooling water temperature can be appropriately controlled to a preset temperature according to the load. I can do it, then,
It is possible to reliably improve fuel efficiency and reduce HC.

In addition, when a diaphragm device is used as a movable valve seat movement control device, the spring force of the diaphragm holding spring can be made smaller than in the past, so the diameter of the diaphragm can be made smaller, and the control device can be constructed at a lower cost. , the degree of freedom in design also increases.

Furthermore, since the thermostat shaft is fixed to the support member with a screw, adjustment can be made easily, and the initial valve opening temperature can be easily set.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a cooling water temperature control device for an internal combustion engine disclosed in Japanese Utility Model Application Publication No. 54-142722, and FIG. 2 is an example of the configuration of the cooling water temperature control device for an internal combustion engine according to the present invention. FIG. 1...Water outlet, 2...Housing, 3...Thermostat, 4...Temperature sensing part, 4A
...Head, 5...Piston, 6...Control piece, 6A
... end, 7 ... valve member, 8 ... spring, 9 ... valve seat, 10 ... cooling water passage, 11 ... diaphragm device (movable valve seat movement control device), 12 ... diaphragm, 13 ... Seal member, 14 ... Negative pressure chamber, 15 ... Lower chamber, 16 ... Negative pressure delay valve, 17
... Stopper, 18 ... Guide member, 19 ... Spring, 20 ... Thermostat housing, 20A
...Cylindrical part, 20B...Locking part, 21...Movable valve seat, 22...Thermostatic valve, 22A...Tapered part, 23...Spring, 24...Valve seat drive shaft, 2
5... Stopper, 26... Negative pressure pipe, 27... Bypass passage, 28... Thermostat shaft.

Claims (1)

[Scope of Claims] 1. A thermostat shaft attached and fixed to a support member provided in a cooling water passage, a temperature-sensing section that slides along the thermostat shaft, and an outer periphery of the temperature-sensing section. comprising a thermostatic valve that is slidable along a surface, and a movable valve seat that the thermostatic valve comes into contact with to close the cooling water passage and takes a predetermined position depending on the load of the internal combustion engine; The position of the movable valve seat and the thermostatic valve with respect to the temperature sensing section is such that the opening temperature of the temperature sensing section of the thermostatic valve is low during high loads, and high during low loads. A cooling water temperature control device for an internal combustion engine, characterized in that it controls the temperature of cooling water. 2. In the cooling water temperature control device for an internal combustion engine according to claim 1, the thermostat shaft is screwed and attached to the support member, and the positional relationship between the temperature sensing section and the thermostat shaft is determined. A cooling water temperature control device for an internal combustion engine, which is adjustable.