JPH01206125A - Oil cooling circuit for oil clutch or the like - Google Patents

Abstract

PURPOSE:To prevent oil from being overheated by mounting a bypass circuit in addition to a cooler circuit and placing a change-over control valve which opens and closes according to the variation in temperature and pressure of oil at the separation point of the cooler circuit from the bypass circuit. CONSTITUTION:When oil is at the low temperature, a partition plate 22 inside a change-over control valve 16 is kept flexed toward an out port 25 and an inport 26 is kept open to a small chamber 21A. That is, a return piping 7A is communicated with a bypass piping 18 via each of a port 26, a small chamber 21A and an out port 24. As a result, oil is carried from the return piping 7A to the bypass pipe 18 via the control valve 16 without passing through a cooler 9, whereby preventing oil from being overcooled and the increase in pressure inside the return piping 7 associated with the increase in temperature of oil. When the temperature of oil get higher, the partition plate 22 inside the control valve 16 is flexed and deformed gradually toward the port 24 so that the return piping 7A will be communicated with the return piping 7B.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention prevents excessive cooling of supplied oil, for example, in an oil supply circuit for an oil clutch or the like, and more specifically, in an oil supply circuit equipped with a cooler circuit. Regarding improvements to make things possible.

[Conventional technology]

For example, in industrial cargo handling vehicles such as forklift trucks where clutches are frequently engaged and engaged, clutch discs are likely to seize and wear out, so conventional methods have been developed to prevent seizure and wear on the clutch discs. A method of spraying oil onto the clutch disc, ie.

A method is used to cool the clutch disc by spraying oil on it. However, the temperature (oil temperature) of the cooled oil that is sprayed onto the clutch in this way naturally rises, and this rise in oil temperature causes damage to various components such as the power steering mechanism. In view of the problem of hardening of oil seals in hydraulic equipment, which can lead to oil leakage, conventionally a cooler circuit has been installed in the oil supply circuit to the oil clutch, and the cooler circuit has been used to cool the clutch disk. A method is used to cool the oil.

FIG. 9 is a diagram schematically showing the oil cooling system as described above, in which the oil tank 1 is connected to the oil tank 1 via the oil pump 4.
The pumped up oil is fed under pressure through the supply pipe 2 and is divided by the flow divider 5, with some of it going to cargo cylinders such as the mast cylinder, tilt cylinder, and side shift cylinder, and the other oil going to the steering wheel. It is supplied to the gearbox 3. The oil supplied to the steering gear box 3 in this way is fed under pressure through the return pipe 7 and is supplied to the cooler 9 (cooler circuit) built in the radiator 8 to cool the oil. A part of the oil is supplied into the case 11 and is sprayed onto the clutch disc, while the other oil is collected into the oil tank 1.

[Problem to be solved by the invention]

However, when the oil is cooled by the cooler circuit as described above, for example, when the outside temperature is low, the oil temperature is low immediately after starting the oil pump, so the oil in such a low temperature state is By feeding the oil into the cooler circuit, the oil is cooled more than necessary and the viscosity of the oil increases.
In other words, the piping resistance in the cooler circuit increases, and the pressure in the piping leading to the cooler circuit increases, which may cause cracks in the piping or oil leakage from the oil seal part of the steering gear box, etc. This will cause problems.

The present invention attempts to improve the above-mentioned problems, and the purpose of the present invention is to prevent an increase in piping resistance by limiting cooling of oil when the oil is in a low temperature state. The point is to make things possible.

That is, one aspect of the present invention is to provide a bypass circuit for the cooler circuit, and when the oil is in a low temperature state, a part or all of it is bypassed through the above-mentioned change in oil temperature, thereby reducing the pressure in the piping. The specific means and effects are as follows.

[Means to solve the problem]

■ Install a bypass circuit for the cooler circuit.

■ A switching control valve that opens and closes depending on changes in oil temperature and oil pressure is installed at the branch of the cooler circuit and bypass circuit. That is, in the former case, the switching control valve is connected to the import to form a switching chamber, and a strip-shaped partition plate is attached to the switching chamber with its end face facing the import, and the switching is performed by the partition plate. The chamber is divided into a small chamber that communicates with the cooler circuit and a small chamber that communicates with the bypass circuit, and the partition plate is formed so that it can be bent and deformed through changes in the temperature of the oil, and the partition plate is made to be able to bend and deform in the diametrical direction of the import. The port is provided so as to be able to communicate with both of the vehicle compartments and either one of the small compartments by bending and deforming the port. For example, bimetal, shape memory alloy, etc. may be used as the material for the partition plate, and in the latter case, a check valve is provided on the bypass circuit side of the switching control valve to open and close according to the oil pressure on the cooler circuit side.

The set pressure by the check valve is preset by the elastic force of the spring.

[For production]

■ When the oil is in a low temperature state When the oil is in a low temperature state, in the former switching control valve, the partition plate is bent and deformed toward the small chamber side that communicates with the cooler circuit, and the import is on the small chamber side that communicates with the bypass circuit. By being fully open, all of the oil is sent to the bypass circuit without being sent to the cooler circuit. In addition, in the latter case, the viscosity of the oil sent to the cooler circuit side increases, the piping resistance in the circuit increases, the pressure in the piping increases, and when it exceeds the set pressure of the check valve, it is difficult to resist this pressure. The check valve opens and oil is pumped into the bypass circuit.

■ When the oil is in a high temperature state As the temperature of the oil rises, the partition plate gradually bends and deforms toward the small chamber that communicates with the bypass circuit, and the import communicates with both compartments. A state is obtained in which a portion is sent to the cooler circuit and the remaining portion is sent to the bypass circuit. The ratio of the opening area of the import to both compartments gradually changes in proportion to the rise in oil temperature.

That is, the opening area on the side of the small chamber communicating with the cooler circuit increases in proportion to the rise in oil temperature, and the amount of oil fed into the cooler circuit gradually increases. As the oil temperature further rises, a state is obtained in which the import is fully opened to the side of the small chamber that communicates with the cooler circuit. That is, all of the oil is sent to the cooler circuit. on the other hand,
The action of a control valve with a check valve is that the oil is in a high temperature state, so the viscosity is low, and the piping resistance is small, so the pressure in the cooler circuit is lower than the set pressure, and the check valve is closed and all of the oil is transferred to the cooler circuit. sent to.

〔Example〕

Specific embodiments of the present invention will be described below with reference to illustrative drawings.

In the drawing shown in FIG. 1, 1 is an oil tank, and 2 is an oil supply pipe extending from the oil tank 1, the tip of which is connected to the steering gear box 3 and connected to the supply pipe 2. An oil pump 4 is attached to an arbitrary intermediate portion thereof, and a supply pipe 6 is branched and extended via a flow divider 5, and the tip end thereof is connected to a lift cylinder and a tilt cylinder (not shown). , connected to cargo handling cylinders such as side shift cylinders. Further, a return pipe 7 is extended from the steering gear box 3, and its tip is connected to a cooler 9 (cooler circuit) built in the radiator 8, and a return pipe 10 is further extended from the cooler 9. The tip thereof is provided so as to pass through the oil clutch case 11 and face into the oil tank 1. Further, an injection nozzle 12 is branched and extended into the return pipe 10 through a flow divider inside the oil clutch case 11, and the tip thereof is provided so as to face the clutch disc, and also has a part of a venturi. An oil recovery nozzle 14 extends downward, and its tip is connected to the oil clutch case 1.
It is provided so as to face an oil reservoir 15 formed at the bottom of the oil tank 1. Further, a switching control valve 16 is attached to the return pipe 7 that connects the above-mentioned steering gear box 3 and the cooler 9 at an arbitrary intermediate part, while a return pipe 10 that connects the cooler 9 and the oil tank 1 has a switching control valve 16 installed therebetween. Same cooler 9
A three-way 17 is attached between the three-way and the oil clutch case 11, and the switching control valve 16 and the three-way 17 are connected by a bypass pipe 18 (bypass circuit).

As shown in FIGS. 2 and 3, the switching control valve 16 is composed of a valve body 19 and a valve cover 20 that covers the opening of the valve body 19. The valve body 19 has a large diameter. The cylindrical portion is recessed, and a pair of small diameter cylindrical portions are recessed on the peripheral edge of the cylindrical portion at an angle of deviation of 180 degrees, and the opening of the large diameter cylindrical portion is closed by the valve cover 20. By covering the oil switching chamber 21, the opening of the small diameter cylinder can be covered with the valve cover 2.
By covering with 0, pivot portions 23 and 23 of the partition plate 22, which will be described later, are respectively formed.

The switching chamber 21 has both pivot joints 2 at its periphery.
A pair of left and right out ports 24 and 25 are opened facing each other with a deviation angle of 90 degrees from 3.23, and one of the out ports 24 is connected to the bypass piping 18, and the other out port The ports 25 are respectively connected to return pipes 7B that communicate with the cooler 9. And again, switching room 21
An import 26 is opened in the center of the steering gear box 3, and the import 26 is connected to a return pipe 7A extending from the steering gear box 3.

Further, the two pivoting portions 23, 23 have narrowed portions 23'', 23', and are provided so as to communicate with the switching chamber 21. Both ends of the partition plate 22 formed in the shape of the seal springs 27, 2
It is supported through 7 so that it can be bent and deformed. More specifically, the partition plate 22 is attached to the switching chamber 21 with its longitudinal end face 22' facing the import 26, and the partition plate 22 communicates the switching chamber 21 with the bypass pipe 18. With small room 21A.

A small chamber 21B communicating with the cooler 9 is defined, and the partition plate 22 is provided so as to be able to bend and deform in an arc across the import 26 in the diametrical direction due to a change in oil temperature.

That is, through the bending deformation of the partition plate 22, the import 26
is in communication with the bypass piping 18 (out port 24), is in communication with the cooler 9 (out port 25),
It is provided so that it is possible to select a three-layer state in which it communicates with both the bypass pipe 18 and the cooler 9 (both out ports 24 and 25) at the same time.

Next, its effect will be explained.

In the schematic diagram shown in FIG. 1, by rotating the oil pump 4, oil stored in the oil tank 1 is sucked up and pumped through the supply pipe 2. The oil that is pressure-fed through the supply pipe 2 is transferred to the flow divider 5.
At the installation position, part of the oil is fed under pressure through the supply piping 6 and supplied to cargo handling cylinders such as lift cylinders, tilt cylinders, and side shift cylinders, while the remaining oil is continuously conveyed under pressure through the supply piping 2. It is supplied to the steering gear box 3.

The oil supplied to the steering gear box 3 is then pressure-fed through the return pipe 7 (7A) to the switching control valve 1.
However, when the temperature of the oil sent to the switching control valve 16 is low, the partition plate 2 is sent to the partition plate 2 as shown in both FIGS.
2 is in a state where it is biased towards the out port 25 side and is bent and deformed;
That is, the partition plate 22 has a T shape. located at import 26
is open to the small chamber 21A side. In other words, the return pipe 7A is in communication with the bypass pipe 18 through the import 26, the small chamber 21A, and the out port 24, and the oil that is pressure-fed through the return pipe 7A to the switching control valve 16 is transferred to the switching control valve 16. 16 and into the bypass pipe 18. However, by sending the oil into the bypass pipe 18 without passing through the cooler 9, excessive cooling of the oil can be prevented.

That is, as shown in FIG. 5, it is possible to prevent the pressure from increasing in the return pipe 7 due to the increase in the viscosity of the oil.

The oil sent into the bypass pipe 18 as described above is sent to the return pipe 10 (IOB) via the bypass pipe 18 and the three-way 17, and is also sent to the return pipe 10 (IOB).
0 (IOB) is fed under pressure toward the oil clutch case 11. A part of the oil that has been pressure-fed into the oil clutch case 11 through the return pipe 10 is supplied to the injection nozzle 12 via the flow divider, and is sprayed from the injection nozzle 12 toward the clutch disk. That is, a cooling effect for the clutch disk can be obtained. Also, the oil sprayed onto the clutch disc is temporarily stored in an oil reservoir 15 formed at the bottom of the oil clutch case 11, but the oil is affected by the negative pressure generated in a part of the venturi formed in the return pipe 10. The oil is sucked up into the oil recovery nozzle 14 through the oil recovery nozzle 14 and is recovered into the return pipe 10 again. and return pipe 10
The remaining oil that has been force-fed into the oil clutch case 11 and the oil that has been recovered from the oil reservoir 15 are subsequently fed under pressure through the return pipe 10 and stored in the oil tank 1 again.

However, as described above, when the oil is continuously sprayed onto the clutch disc while the oil is circulating through each part of the supply pipe 7 (7A), the bypass pipe 18, and the return pipe 10 (IOB), the temperature of the oil increases. As the oil temperature rises, the partition plate 22 in the switching control valve 16 gradually bends and deforms toward the outport 24. As shown in FIG. 4, the partition plate 22 is
. An effect of bending and deforming in the T direction from the position can be obtained. By bending and deforming the partition plate 22 to the T1 position in this manner, a state is obtained in which the import 26 opens toward the small chamber 21B. In other words, the return pipe 7A is the import 26. A state is obtained in which the oil is communicated with the return pipe 7B through the small chamber 21B and the out port 25, and the oil that is pressure-fed through the return pipe 7A to the switching control valve 16 is transferred to the cooler 9 through the switching control valve 16 and the return pipe 7B. sent to. The oil sent into the cooler 9 is cooled while passing through the same group and is sent to the return pipe 11 (IIA), and is also pressure-fed through the return pipe 11 (IIA) to cool the clutch disc as described above. This effect can be obtained.

Note that the partition plate 22 does not undergo sudden bending deformation from the T0 position to the T8 position, but due to the temperature rise of the oil. It will be bent and deformed slowly from the position to the T3 position. When the partition cutout 22 moves from the T1 position to the T2 position, the end face 22' of the partition plate 22 crosses the import 26 in the diametrical direction, but during this time, the import 26 separates the small chambers 21A and 21B. A state in which both are open is obtained. In other words, the return pipe 7A is the import 26. Small room 21A, outport 2
A state in which the bypass pipe 7A communicates with the bypass pipe 7A through each part of 4, and a state in which the rotten pipe 7B communicates with the rotten pipe 7B through the import 26, the small chamber 21B, and the out port 25 are obtained.
Part of the oil that has been pressure-fed through A to the switching control valve 16 is sent from the switching control valve 16 to the return piping 10 (IOA) via the bypass piping 18 and the three-way 17, and the other oil is fed to the switching control valve 16. valve 16
The return pipe 7B passes through each part of the cooler 9 and returns to the return pipe 1.
0 (IOA).

In this way, the oil pressure-fed to the return pipe 7A gradually changes its ratio and is distributed and sent to the bypass pipe 18 and the cooler 9, so that the oil is applied to the clutch disc as shown in Fig. 6. Spraying can stabilize the temperature. In the above embodiment, the partition plate 22 is made of bimetal, but it is also possible to use a shape memory alloy instead of bimetal.

Next, another embodiment will be described based on FIGS. 7 and 8.

In this embodiment, a switching control valve 16A is installed in the piping 7, similar to the switching control valve 16 of the previous embodiment. The valve body 28 of the switching control valve 16A is an import 2 into which oil from the steering gear box 3 flows.
9, an out port 30 provided to communicate with the cooler 9, and an out port 31 communicated with the bypass piping 18. The import 29 pivots to a valve cover 32 in which a small-diameter import 29 is transparently connected to a large-diameter cylindrical portion that is bored almost to the center of the valve body 28.
8A is formed. On the other hand, the outport 30 is formed by boring a small-diameter cylindrical hole facing the import 29 and communicating with the same chamber 28A. Further, the out port 31 is bored perpendicularly to a tapered valve hole 33 provided parallel to the out port 30 and communicating with the chamber 28A. A check valve 38 is located inside the valve hole 33.
is formed. That is, a check ball 34 is inserted into the valve hole 33, and the check ball 34
is biased against a tapered seat portion 37 by a spring 35 provided between the valve cover 36 that closes the valve hole 33 and the valve cover 36 .

The spring 35 has a preset spring constant and is provided as a set pressure, so that the check ball 34 separates from the seat portion 37 when the pressure in the chamber 28A exceeds the set pressure.

Next, its effect will be explained.

The flow of oil from the oil tank 1 to the switching control valve 16A is the same as in the previous embodiment, and will therefore be omitted.

When the temperature of the oil sent to the switching control valve 16A is low immediately after startup, if the oil is sent to the cooler 9, the oil will be excessively cooled and the viscosity of the oil will increase, resulting in piping resistance in the return piping 7. increases, and the pressure in the return pipe 7 and the chamber 28A of the switching control valve 16A increases. When the pressure in the chamber 28A becomes higher than the set pressure of the check valve 38, the check ball 34 separates from the seat portion 37 against the biasing force of the spring 35, as shown in FIG. The oil flowing into the out port 31 goes to the bypass piping 18 side where the pressure is low.
is drained through. Conversely, when the temperature of the oil increases, the viscosity of the oil increases, so the piping resistance decreases, and the pressure in the return piping 7 and the chamber 28A decreases, so the check ball 34 is moved to the seat portion 37 by the spring 35.
is brought into contact with. Therefore, oil flowing in from the import 29 flows into the cooler 9 through the out port 30.

Further, in the above two embodiments, the cooler 9 built into the radiator 8 is used, but it is also possible to use an air-cooled cooler. Furthermore, although the above embodiment describes a cooling system for an oil clutch, the present invention is not limited to this and can be used for general purposes other than oil clutches, such as a cooling system for a torque converter. .

〔Effect of the invention〕

The present invention is configured as described above, and as described above, a bypass circuit is provided for the cooler circuit, and when the oil is in a low temperature state, the bypass circuit is bypassed without sending the oil to the cooler circuit. By doing so, it became possible to prevent excessive cooling of the oil.

By being able to prevent over-cooling of the oil in this way, it is possible to prevent an increase in piping resistance in the cooler circuit due to increased oil viscosity, which in turn prevents the piping and hydraulic equipment leading to the cooler circuit from increasing. We have now been able to prevent the internal pressure from increasing. That is.

It has now become possible to prevent damage to the piping and oil leakage from hydraulic equipment.

In particular, in the present invention, by providing a switching control valve that opens and closes depending on oil temperature changes and oil pressure changes at the branch part of the cooler circuit and the bypass circuit, A flexibly deformable partition plate is provided facing the inboard, and the circuit is switched by bending and deforming the partition plate along the diameter direction of the inboard as the temperature of the oil increases. Now, by opening and closing the check valve according to the pressure inside the piping and switching one circuit, it has become possible to smoothly switch the pressure and temperature inside the piping without sudden changes. . And again,
With the above configuration, there is no pressure loss like when using a spool valve, and there is no surge pressure like when using a solenoid valve, allowing smooth circuit switching. I was able to do it.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the entire oil cooling circuit according to the present invention, FIG. 2 is a vertical sectional view of the switching control valve, FIG. 3 is a side sectional view of the switching control valve, and FIG. 4 is also a switching control valve. FIG. 3 is a schematic diagram showing the operating state of the valve. FIG. 5 is a graph showing a comparison of the hydraulic pressure generated in the steering gear box with the conventional one, and FIG. 6 is a graph showing a comparison of the oil temperature supplied to the oil clutch with the conventional one. Also, the seventh
The figure is a sectional view of a switching control valve showing another embodiment of the present invention, FIG. 8 is a sectional view of the switching control valve showing its operation, and FIG. 9 is a schematic diagram showing the entire conventional oil cooling circuit. . 1... Oil tank, 2... Supply piping, 3A...
Steering gear box, 4...Oil pump, 5
...Flow divider, 6...Supply piping, 7 (
7A. 7B)... Return piping, 8... Radiator, 9...
Cooler, 10 (IOA, l0B)...Return piping,
DESCRIPTION OF SYMBOLS 11... Oil clutch case, 12... Injection nozzle, 14... Oil recovery nozzle, 15... Oil reservoir, 16° 16A... Switching control valve, 17... Three-way, 18...・Bypass piping, 19...Valve body, 2゜...Valve cover, 21...Switching chamber, 21A, 21B...Small chamber, 22...Partition plate, 22'...End face, 23. ... Pivotal joint, 23'...
Narrowing part, 24, 25... Out port, 26... Import, 27... Seal spring, 28... Valve body, 28A... Chamber, 29... Import, 30,
31... Out port, 32... Valve cover, 3
3... Valve hole, 34... Check ball, 35...
...Spring, 36...Valve cover, 37...
Seat part, 38...check valve. Patent applicant: Toyoda Automatic Loom Works, Ltd.
2 Figure 9 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 TI T2 Oil temperature Figure 6 TI T2 Oil temperature Figure 8

Claims (2)

[Claims] (1) An oil cooling circuit equipped with a cooler circuit, in which a bypass circuit is provided for the cooler circuit, and a switching control valve is provided at the branch of the cooler circuit and the bypass circuit. A switching room is formed by communicating with the cooler circuit, and a partition plate formed in the form of a strip is installed in the switching room with its end face facing the import. An oil cooling circuit for an oil clutch or the like, which is divided into small chambers that communicate with the circuit, and the partition plate is formed so that it can be bent and deformed along the diameter direction of the import through temperature changes in the oil. (2) An oil cooling circuit comprising a cooler circuit, wherein a bypass circuit is provided for the cooler circuit, and a switching control valve is provided at a branch of the cooler circuit and the bypass circuit, and a bypass circuit for the switching control valve is provided. An oil cooling circuit such as an oil clutch that has a check valve on the side that opens and closes depending on the oil pressure on the cooler circuit side.