JP2539335Y2 - Automotive cooling fan drive - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention detects the temperature of the engine cooling water and controls the pressure in the hydraulic circuit with a balanced piston type sequence valve. To a hydraulic motor for driving a cooling fan for an automobile.

(Prior Art) In a conventional driving device for a cooling fan for an automobile, a cooling water temperature is detected, and the pilot valve opening of a balanced piston type sequence valve is controlled by an electromagnetic proportional pressure control valve in accordance with the detected cooling water temperature.

Conventionally, a proportional pressure control valve proposed in Japanese Patent Application Laid-Open No. 62-147181 detects a cooling water temperature with a water temperature sensor, determines this by an ECU instead of an electric signal, and opens a bypass circuit with the solenoid valve. The fan speed is controlled by varying the degree.

FIG. 8 shows a fluid circuit in which the conventional pressure control valve is used. Referring to FIG. 8, reference numeral 250 denotes a hydraulic pump driven by an automobile engine, and a working fluid from the pump 250 is supplied to a hydraulic motor 252 through a fluid passage 251. Supplied. The hydraulic motor 252 rotates a cooling fan 253, and the cooling fan 253 is a condenser for a car radiator and a car air conditioner.
Is cooled. 255 is a bypass passage for hydraulic motor 2
It is arranged in parallel with 52. EC for coil of pressure control valve
An electric signal flows from the U260, and the ECU 260 has a water temperature sensor 261 and a high pressure switch 262 installed on the condenser 254.
Receive a signal from That is, when it is determined from the electric signal from the water temperature sensor 261 that the condenser 254 requires cooling capacity, an electric signal is applied to the coil from the ECU 260 to that effect. The coil is actuated by this electric signal to close the control valve.

Therefore, in a state where cooling capacity is required for the condenser 254, the passage valve portion 200 is closed, and the upstream and downstream voltages of the hydraulic motor 252 are reduced by the current supplied to the coil.
It can be set and controlled arbitrarily.
Increase / decrease control. Similarly, pressure switch 262
Issues a signal indicating that the cooling capacity of the condenser 254 is required, the ECU 260 similarly applies an electric signal to the coil and outputs an electric signal to the coil such that the passage valve unit 200 opens the passage.

(Problem to be Solved by the Invention) In the system using the conventional electromagnetic proportional pressure control valve, the water temperature sensors 261 and E are used to operate the pilot valve.
Because CU260 and solenoid valve are required and the number of parts is large,
The cost was high, and it was difficult to mount it on a vehicle.

A vehicle cooling system using a thermo-wax for driving a relief valve in a hydraulic circuit for driving a fan is disclosed in Japanese Patent Laid-Open No.
It is proposed in Japanese Patent Publication No. 139918. However, in this system, the opening degree of the bypass circuit is directly controlled by the thermowax (direct motion type), so that the chattering phenomenon due to the pressure pulsation easily occurs, and the output of the thermowax is overcome in order to overcome the dynamic pressure of the high pressure fluid. Since it is necessary to increase the size, there is a disadvantage that the size is increased.

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned conventional problems by providing a cooling fan drive apparatus for an automobile in which the temperature of a cooling water is detected by a thermo wax and the hydraulic pressure is controlled by a balanced piston type sequence valve.

[Structure of device]

(Means for Solving the Problems) For this reason, the present invention supplies the discharge hydraulic pressure of a hydraulic pump driven by an engine to a hydraulic motor equipped with a cooling fan through a hydraulic supply passage to rotate the cooling fan. In the cooling fan driving device, a first pressure chamber and a second pressure chamber which are movably fitted into the cylinder and are movably fitted in the cylinder, and communicate with the discharge passage and the hydraulic supply passage of the hydraulic pump in the cylinder. A balanced piston comprising a piston forming a partition; a first orifice provided between the first pressure chamber and the hydraulic pressure supply passage;
The branch passage, which is interposed in a branch passage that communicates the hydraulic pressure supply passage between the orifice and the hydraulic motor and the second pressure chamber and a passage that communicates the second pressure chamber and a suction passage of the hydraulic pump, A pilot valve that controls the opening and closing of the passage to control the pressure in the pressure chamber; and a bypass passage that communicates the first pressure chamber with a suction passage of the hydraulic pump. A balanced piston type sequence valve for controlling the communication between the bypass passage and the first pressure chamber by the pressure difference between the two pressure chambers and controlling the hydraulic pressure supplied to the hydraulic motor is provided. Second
An orifice is interposed, and the pilot valve is driven by thermowax which increases in volume according to the cooling water temperature of the engine, and the pilot valve is urged by elastic members from both sides in the operating axial direction, and The thermo wax is disposed at the other end of one elastic member,
Further, a mechanism capable of absorbing the expansion of the thermowax even after the pilot valve is fully closed is provided as a means for solving the problem.

(Operation) After the oil discharged from the hydraulic pump is reduced in pressure by the passage resistance of the orifice in the balanced piston type sequence valve, the hydraulic motor is driven to rotate the cooling fan. Here, when the pilot valve of the balanced piston type sequence valve is opened, the pressure in the second pressure chamber of the balanced piston decreases, so that the piston moves to the second pressure chamber side and balances, and the hydraulic pump The amount of oil flowing into the bypass passage increases, the amount of oil flowing into the hydraulic motor decreases, and the rotation speed of the cooling fan decreases.

When the temperature of the cooling water rises, the wax in the thermowax expands and pushes the poppet of the pilot valve to close the circuit, and a large amount of oil from the hydraulic pump flows to the hydraulic motor to increase the rotation speed of the cooling fan.

(Embodiment) The present invention will be described below with reference to the embodiment of the drawings.
FIG. 3 to FIG. 3 show an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a hydraulic pump which is rotationally driven by an engine 2. A working fluid (hereinafter referred to as "oil") discharged from a discharge side of the hydraulic pump 1 passes through a passage 3a to a first pressure chamber 4 of a balanced piston 3. After flowing into the hydraulic motor 6 through the passage 22 through the orifice 5 to drive the hydraulic motor 6, the cooling fan 7 is rotated by the hydraulic motor, and then through the passage 23 to the suction side of the hydraulic pump 1. I'm going back. The inside of the cylinder 11 of the balanced piston 3 is divided by the piston 9 into the first pressure chamber 4 and the second pressure chamber 8. The piston 9 is urged rightward in the figure by a spring 10, and controls the communication between the passage 3a and the bypass passage 12, that is, the opening degree of the bypass passage 12. The one-way valve 9a incorporated in the piston 9 is normally closed by the spring 9b, but when the piston 9 is stuck for some reason and does not move, the hydraulic pressure in the second pressure chamber 8 is reduced by the bypass passage 12 Work to escape to. A pilot valve 13 is provided on passages 24 and 24b branching from the downstream side of the orifice 5 and leading to a passage 23, and a thermo wax having a tip inserted into the pilot valve 13 and the cooling water passage 14. 15 is connected via a first spring 18. The balanced piston 3, the orifice 5, the bypass passage 12, the passage 24, and the pilot valve 13 configured as described above constitute a balanced piston type sequence valve. In FIG. 2, reference numeral 5a denotes a second orifice.

FIG. 3 shows a detailed view of the pilot valve 13 and the thermowax 15. Pilot valve 13 is rod 15 of thermo wax 15
a guide 16 having one end in contact with b and a concave hole 16a at the other end;
The shaft 17 having one end inserted into the concave hole 16a of the guide 16
And a poppet 19 that engages with the other end of the shaft 17 to open and close the communication between the oil inlet 13a and the oil outlet 13b provided in the housing 25.
A second spring 21 for urging the poppet 19 in the direction of the shaft 17 so as to open the communication between the guide 16 and the shaft 17 so as to open the communication between the guide 16 and the shaft 17 so as to abut the rod 15b and the poppet 19, respectively. And a first spring 18 that is energized. Reference numeral 20 denotes a sleeve inserted into the housing 25 and screwed on a lid member 26 screwed to the housing 25. The sleeve 20 accommodates a second spring 21 and a poppet 19 therein. 27 is a sealing material, 28 is a body connecting the lid member 26 and the casing 29, and houses the first spring 18, the guide 16 and the shaft 17 inside. Numeral 30 is a case that constitutes the thermo wax 15.
The wax 15a is built in, and the rod 15b
And a wax 15a, and a diaphragm 15c for sealing outflow of the wax 15a is fixed by a pressing member 15d. One end of the case 30 is inserted into the cooling water passage 14. A ring 31 is provided between the lid member 26 and the sleeve 20 and serves as a stopper for the pocket 19.
The shaft 17 penetrates through the central portion of the cover member 26 and the tip is engaged with the poppet as described above.

Next, the operation will be described. The oil discharged by the hydraulic pump 1 flows into the first pressure chamber 4 of the balanced piston 3 through the passage 3a, and then flows into the hydraulic motor 6 through the orifice 5 and the passage 22. After the cooling fan 7 is rotated by driving the hydraulic motor 6, the cooling fan 7 is returned to the suction side of the hydraulic pump 1 via the passage 23. When the oil passes through the orifice 5, the pressure of the oil is reduced by the passage resistance, so that the pressure P ₁ of the first pressure chamber 4 of the balanced piston 3 is increased.
The pressure P ₂ of the second pressure chamber 8 as compared to the smaller (P _1> P _2).

Accordingly, the piston 9 moves in the cylinder 11 while maintaining a balance with the pressure P ₁ and (the pressure P ₂ + the force of the piston spring 10), and controls the opening degree of the bypass passage 12. For example, since the discharge amount of oil increases and the engine 2 speed and increases, the greater the pressure difference between the pressure P ₁ and the pressure P _2,
The piston 9 moves to the left in the figure, and balances at a position where the bypass passage 12 is opened by a certain amount as shown in FIG. Therefore, excess oil returns to the suction side of the hydraulic pump 1 via the bypass passage 12, so that the flow rate to the hydraulic motor 6 is kept constant, and the fan speed is kept constant.

Here in order to change the fan speed includes a pressure P ₁
There is a need to change the balance of P _2. The pilot valve 13 plays a role in this. When the valve 13 is opened, the second pressure chamber 8 of the cylinder 11 of the balanced piston 3 is moved to the suction side of the hydraulic pump 1 through the passages 24a, 24, 24b, 23. drop in pressure P ₂ to be opened through the piston 9 is balanced by moving further to the left in the figure from the position. As a result, the opening amount of the bypass passage 12 increases, and as a result, the amount of oil flowing into the hydraulic motor 6 decreases, and the rotation speed of the cooling fan 8 decreases.

The above is the operation principle of the rotation speed control of the hydraulic motor 6 using the so-called balanced piston type sequence valve. In the present invention, in order to control the opening amount of the pilot valve 13 in this system, the cooling water passage 14 is controlled. It is characterized by using a thermowax 15 in which a case 30 is inserted.

The operation of this characteristic point will be described with reference to FIGS. 3 to 5. In FIG.
After flowing into the vicinity of the case 30 from 14a, it flows out from the outlet 14b. On the other hand, as shown in FIG. 4, when the water temperature becomes equal to or higher than T ₁ (° C.), the wax 15a starts to liquefy and pushes the rod 15b against the first spring 18 through the diaphragm 15c. Now the cooling water temperature is low, ie T ₁
In the case of (° C.) or less, the rod 15b and the guide 16 do not move. At this time, the first spring between the guide 16 and the shaft 17
The mounting load of 18 and the mounting load of the second spring 21 between the poppet 19 and the sleeve 20 are set to be balanced at the fully opened position of the poppet 19, that is, in the state of FIG.

In this state, the pressure P ₂ in the second pressure chamber 8 of the balanced piston 3 shown in FIG. 1 is released to the suction side of the hydraulic pump 1 and decreases, and the flow rate in the bypass passage 12 becomes maximum. The fan speed is kept low. Here, when the cooling water temperature rises and becomes equal to or higher than T ₁ (° C.), the rod 15b starts operating leftward in FIG. 3, and the load generated by the first spring 18 increases. At the same time, the second spring 21 is contracted, and the poppet 19 starts operating in a direction to reduce the opening area. FIG. 5 (b) shows the fully closed state of the pilot valve.
In this case the pressure P ₂ of FIG. 1 is highest, the flow rate of the bypass passage 12 is minimized, the fan rotational speed is kept high.

By the above operation, the oil flow between the orifice inlet 13a and the oil outlet 13b of the pilot valve 13 is varied. That is, by varying the pressure P ₂ of FIG. 1, the system can control the fan speed in response to coolant temperature as shown in Figure 6. Here T ₂ are FIG. 5 (b), i.e., while indicating the water temperature of the poppet is fully closed, the rod 15b as can be seen from Figure 4 continues to stretch even T ₂ or more. Therefore, in order to prevent the internal pressure in the case 30 from rising due to the wax 15a, the movable range of the guide 16 is limited to the rod 15b even after the poppet is fully closed.
The recess 16a into which the shaft 17 is inserted is made deeper so that the elongation of the shaft 17 can be absorbed, and the guide 16 can be moved along the shaft 17 against the first spring 18 when pushed by the rod 15b. .

FIG. 7 shows that if the entire stroke of the poppet 19 is too long,
This shows that the total length becomes long to set the same poppet valve opening area. FIG. 7A shows a case of a short stroke, and FIG. 7B shows a case of a long stroke. This is because the hole diameter d, the stroke S, the valve opening area A, and the poppet tip angle 2φ have the following relationship.

It should be noted that if A and d are constant, it is clear that the shorter the stroke S, the larger φ can be, and the shorter the total length can be.

In the present invention, therefore, the spring constant K ₁ of the first spring 18 allow reasonably short stroke of the poppet 19, the second
It is set the spring constant K ₂ of the spring 21. The relationship between the rod stroke S _R and poppet stroke S _P is expressed by the following equation.

[Effects of the Invention] As described in detail above, the present invention is configured, and since the thermo wax only drives the pilot valve of the balanced piston type sequence valve, the opening degree of the conventional bypass passage is controlled by the thermo wax. As in the case of the control, the chattering phenomenon due to the pressure pulsation is not easily caused, and it is not necessary to increase the output of the thermowax.

Generally, the relationship between the cooling fan rotation speed Nf, the flow rate Q, and the discharge pressure P is Nf∝Q∝√p, and the rotation speed Nf is proportional to the first order of the flow rate Q, and is proportional to 1/2 of the discharge pressure P. I do. In the present invention, the supply pressure to the hydraulic motor is controlled by the balanced piston type sequence valve to control the rotation speed of the cooling fan, so that the fluctuation of the rotation speed of the cooling fan due to the fluctuation of the discharge pressure P is small. Excellent in nature.

Even if the oil temperature rises and the volumetric efficiency of the hydraulic motor decreases, the hydraulic pressure supplied to the hydraulic motor is controlled by the balanced piston type sequence valve and the supply flow rate is increased, so that the cooling fan speed does not decrease. Also, fluctuations (pulsations) in the discharge pressure of the hydraulic pump are small.

Further, by controlling the pressure of the second pressure chamber communicated via the branch passage by a pilot valve according to the cooling water temperature,
Since the hydraulic pressure supplied to the hydraulic motor is controlled, the pressure loss to the hydraulic motor inlet is small (only the first orifice), and the horsepower consumed by the hydraulic pump can be reduced.

By the way, a plunger that opens and closes a bypass circuit that bypasses a supply passage to a hydraulic motor for driving a cooling fan as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-139918 is changed to a motor supply hydraulic pressure (dynamic pressure) acting on the plunger. In contrast, the energizing force of the spring that constantly energizes the bypass circuit to the closing side is increased by thermowax according to the cooling water temperature,
When the fan speed is controlled in accordance with the temperature of the cooling water, chattering of the plunger tends to decrease due to a change (pressure pulsation) in the motor supply oil pressure (dynamic pressure) acting on the plunger. , Not only the rotation speed becomes unstable, but also the motor supply hydraulic pressure (dynamic pressure)
Therefore, it is necessary to increase the output of the thermowax for reducing the spring against the pressure, and therefore the size of the control valve increases.

On the other hand, in the present invention, the pressure of the second pressure chamber, in which the hydraulic pressure supplied to the hydraulic motor is guided through the second orifice and the branch passage, is increased by the pilot valve driven by thermowax according to the cooling water temperature. (2) The piston of the balanced piston is changed by controlling the communication of the passage between the pressure chamber and the suction passage of the hydraulic pump to change the pressure difference between the first pressure chamber and the second pressure chamber. Controls the communication between the bypass passage and the first pressure chamber, and controls the hydraulic pressure supplied to the hydraulic motor in accordance with the cooling water temperature.

Therefore, for example, when the cooling water temperature is high, even if the pressure in the first pressure chamber fluctuates due to the hydraulic pump pressure pulsation, the second pressure chamber is communicated with the hydraulic supply passage via the second orifice and the branch passage. The fluctuation of the pressure in the second pressure chamber is suppressed (damper effect by the second orifice). Therefore, the movement of the piston of the balanced piston due to the pressure pulsation of the hydraulic pump (chattering) is attenuated and suppressed, and the fluctuation of the hydraulic pressure supplied to the hydraulic motor due to the chattering of the piston prevents the rotation speed of the cooling fan from fluctuating. Is done. In addition, the supply oil pressure to the hydraulic motor does not act on the pilot valve, but the supply oil pressure is reduced by the second orifice. Therefore, the output of the thermowax acting against the reduced pressure is applied. Is small and the pilot valve can be downsized.

[Brief description of the drawings]

1 is a system diagram of a cooling fan driving device for an automobile showing an embodiment of the present invention, FIG. 2 is a detailed sectional view of a balanced piston in FIG. 1, and FIG. 3 is a balanced piston type sequence in FIG. Detailed sectional view of the valve, FIG. 4 is a characteristic diagram of the thermowax, FIGS. 5 (a) and 5 (b) are explanatory diagrams of the operation of the pilot valve, and FIG. 6 is a diagram showing the relationship between water temperature and fan speed. 7 (a) and 7 (b) are explanatory diagrams of a poppet shape, and FIG. 8 is a system diagram of a conventional electromagnetic proportional pressure control valve. Description of main parts in the drawing 1 ... hydraulic pump, 2 ... engine 3 ... balanced piston, 4 ... first pressure chamber 5 ... orifice, 6 ... hydraulic motor 7 ... cooling fan, 8 ... second pressure chamber 9 ... piston, 10 ... Spring 11 ... Cylinder, 12 ... Bypass passage 13 ... Pilot valve, 14 ... Cooling water passage 15 ... Thermo wax, 16 ... Guide 16a ... Concave hole, 17 ... Shaft 18 ... First spring, 19 ... Popet 20 ... Sleeve, 21 … Second spring 24,24a, 24b… passageway, 30… case

Claims (3)

(57) [Scope of request for utility model registration] 1. A cooling fan drive device for supplying discharge hydraulic pressure of a hydraulic pump driven by an engine to a hydraulic motor provided with a cooling fan through a hydraulic supply passage to rotate the cooling fan. A balanced piston including a piston that movably fits in the cylinder and defines a first pressure chamber and a second pressure chamber that communicate with the discharge passage and the hydraulic supply passage of the hydraulic pump in the cylinder. A first orifice provided between the first pressure chamber and the hydraulic pressure supply passage; a branch passage communicating the hydraulic pressure supply passage between the first orifice and the hydraulic motor with the second pressure chamber; A pilot valve interposed in a passage communicating the pressure chamber with the suction passage of the hydraulic pump, and controlling opening and closing of the passage to control the pressure of the second pressure chamber; The first pressure chamber and a bypass passage communicating the suction passage of the hydraulic pump, and the pressure difference between the first pressure chamber and the second pressure chamber causes the bypass passage and the first pressure chamber to be connected to each other. A balanced piston type sequence valve for controlling the communication with the hydraulic motor and controlling the hydraulic pressure supplied to the hydraulic motor is provided, a second orifice is interposed in the branch passage, and the pilot valve is set in accordance with the cooling water temperature of the engine. A cooling fan driving device for an automobile, wherein the driving device is driven by a thermowax that increases the volume. 2. The cooling fan drive device for an automobile according to claim 1, wherein the pilot valve is urged by elastic members from both sides in the operating axis direction thereof, and the other end of one elastic member is provided with the thermostat. An automotive cooling fan drive, wherein wax is provided. 3. An automobile cooling fan drive according to claim 1, further comprising a mechanism capable of absorbing expansion of the thermowax even after the pilot valve is fully closed. apparatus.