JPH0526334A - Controller of pump discharge pressure - Google Patents

Abstract

PURPOSE: To reduce oil hammering and pressure drop by relaxing pressure change of a pressure control valve when a changeover valve communicating the delivery side with the suction side of an oil pump having a plurality of delivery openings is switched from interruption to communication. CONSTITUTION: An oil pump 2 is driven to rotate during engine operation to generate a predetermined secondary pressure Ps for uninterruptedly supplying oil to a secondary control valve 20 through a main port 3. With the secondary pressure Ps as the main pressure, a predetermined lubricating pressure Po is generated by a lubricating control valve 22 and a primary pressure Pp is generated by a primary control valve 24 in correspondence with transmission ratio i. At that time, a control unit 40 calculates, compares and determines the flow rate Qp of the main port and the total use flow rate Qs . When Qs is larger than Qp as in the case of acceleration during low speed running, a changeover control valve 12 interrupts the lubricating pressure Po and the oil from a sub- port 4 is interrupted by means of a changeover valve 10. The flow rate therefrom is smoothly increased with respect to the control valve 20 under the pressure reducing control by the control unit 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pressure source device having an oil pump means having a plurality of discharge ports and controlling the oil pump means so as to selectively operate the oil pump means. The present invention relates to a pump discharge pressure control device that smoothly controls pressure.

[0002]

2. Description of the Related Art For example, a belt type continuously variable transmission for a vehicle has an oil pump which is always driven by engine power to generate hydraulic pressure. The pump discharge pressure is regulated to a predetermined secondary pressure. The secondary pressure is generated and the primary pressure, the lubricating pressure, and the like are generated. The secondary pressure is controlled in a wide range according to the transmission torque and the like. Therefore, particularly when it is mounted on a vehicle with a high output engine, a plurality of oil pump means may be provided to increase the pump discharge capacity. You will need it. on the other hand,
When a plurality of oil pump means are used, an increase in pump loss inevitably occurs when the secondary pressure is low, and therefore it is necessary to control in consideration of this point.

Conventionally, for example, Japanese Patent Laid-Open No. 61-215853 discloses a conventional technique for controlling a hydraulic power source device having a plurality of oil pump means. here,
It has two oil pumps driven by one drive source, and the discharge sides of both oil pumps are connected by a check valve. In addition, the relief valve is connected to one oil pump by bypass, and the relief valve is electrically switched to load the oil pump only when the oil is insufficient to increase the pump capacity and reduce the power consumption. It has been shown to reduce.

[0004]

By the way, in the above-mentioned prior art, since the switching is simply controlled by the relief valve according to the state of oil consumption, the flow rate on the control side is large at the time of this switching. Change. Therefore, if the flow rate response of the flow rate control valve is poor, oil hammer may occur on the control side or pressure may drop, resulting in overload, deterioration of durability, vibration,
In the case of shocks and belt type continuously variable transmissions, problems such as belt slip may occur.

The present invention has been made in view of the above points, and an object thereof is to prevent oil hammer and pressure when switching the oil pump means having a plurality of discharge ports to selectively operate. It is an object of the present invention to provide a pump discharge pressure control device capable of reducing a drop.

[0006]

In order to achieve the above object, a pump discharge pressure control device according to the present invention is such that one discharge side of an oil pump means having a plurality of discharge ports is a pressure that constantly regulates pressure. In the hydraulic pressure source device that communicates with the control valve, and the other discharge side communicates with the pressure control valve through the check valve and also communicates with the suction side through the switching valve, at least from the shut-off position to the communication position of the switching valve. At the time of switching to, the pressure control valve is provided with a mitigating means for temporarily mitigating the pressure fluctuation of the pressure control valve.

[0007]

According to the above construction, when the other switching valve of the oil pump means having a plurality of discharge ports is operated to the shut-off position, the pump flow rate is also added and the pump capacity is doubled.
When operated to the communication position, it becomes a no-load operation state. And
At least at the time of switching to the communication position by the mitigating means,
The pressure of the pressure control valve is prevented from dropping, and changes smoothly.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a case of electronically controlling the pump discharge pressure will be described as a first embodiment of the present invention.

For example, a hydraulic control system for a belt type continuously variable transmission will be described. Reference numeral 1 is a hydraulic source device, and a variable displacement type oil pump 2 of a roller vane type having a plurality of suction and discharge ports is an engine power source. It is provided so as to be always driven by. The oil pump 2 has a main port 3 having a pair of suction ports 3a and a discharge port 3b in the rotational direction of a rotor provided with vanes, and a similar suction port 4a and a discharge port 4b.
And a sub-port 4 is formed which has both suction ports 3
The oil passages 5a, 4a communicate with the oil pan 6. The discharge port 3b of the main port 3 communicates with the secondary control valve 20 via the oil passage 7 to constantly supply oil, and the oil passage 8 of the discharge port 4b of the subport 4 is connected to the suction side via the switching valve 10. In addition to communicating with each other, the oil passage 7 is connected via a check valve 9.
Is in communication with.

The switching valve 10 is turned on / off to recirculate a large amount of oil from the sub-port 4 for no load operation, or shut off for load operation to supply oil to the secondary control valve 20 via the check valve 9. The switching control valve 12 is provided on the control side of the switching valve 10 via the oil passage 11.
Communicate with each other. Further, the drain side of the secondary control valve 20 communicates with the lubrication control valve 22 via the oil passage 21, and generates a constant lubrication pressure Po used for lubrication and other purposes,
This lubricating pressure Po is guided to the switching control valve 12 by the oil passage 13. The switching control valve 12 is a three-way valve, and the control unit 4
An electric signal from 0 acts on the switching valve 10 with the lubricating pressure Po or drains the operating side of the switching valve 10.

The secondary control valve 20 regulates the pressure by an electric signal to control the secondary pressure Ps in a wide range.
The secondary pressure Ps is configured to generate the primary pressure Pp by being guided to the primary control valve 24 by the oil passage 23 and flow rate controlled.

Next, the electronic control system will be explained. Calculation of the engine speed sensor 30, the accelerator opening sensor 32, the oil temperature sensor 33, and the gear ratio i for detecting the engine speed Ne, the accelerator opening, the oil temperature To and the like. With the unit 31, signals from these sensors and the gear ratio calculation unit 31 are input to the control unit 40.

The control unit 40 controls the engine speed N
e, the main port flow rate calculation unit 41 to which the oil temperature To is input is provided, and the port flow rate Qp generated in the main port 3 according to each operating state is calculated by these elements. Further, it has a use flow rate calculation unit 42 for inputting the engine speed Ne, the gear ratio i, the accelerator opening degree, etc. The used flow rate Qs used in the entire gear transmission hydraulic control system is calculated. The signals of these two flow rates Qp and Qs are input to the switching determination unit 43, and the two are compared and Qp <Qs
When + Qm, it is determined that switching can be turned off, and when Qp ≧ Qs, it is determined that switching can be turned on. Here, the used flow rate Qs
When the switching is judged to be ON and the operation is switched to only the main port 3, the flow rate is halved and the pressure is likely to drop. To prevent this, the secondary pressure P is set in advance.
You can increase s.

Therefore, based on the above control principle, switching ON
The signal is input to the secondary pressurization setting unit 44 and the flow rate Q
The predetermined pressure increase amount + Ps is calculated from factors such as p, Qs, secondary pressure Ps, and oil temperature To. The signal of the switching ON and the pressure increase amount + Ps is input to the timing setting unit 45, and the pressure increase start time t1 prior to the change time to and the pressure increase end time t2 after the change time are calculated from the above-mentioned factors, pressure increase amount + Ps. Set. Then, the pressure increasing signal is output to the secondary control unit 46 at the pressure increasing times t1 and t2, and the switching signal is output to the switching control valve 12 via the driving unit 47 at the switching time to. on the other hand,
For the switching OFF signal, the secondary pressure reduction setting unit 48
And a timing setting unit 49, which similarly sets a predetermined pressure reduction amount -Ps and pressure reduction start and end times t1 and t2 with respect to the switching time point to. The pressure reducing signal is output to the secondary controller 46 and the switching signal is output to the switching control valve 12 at a predetermined timing.

Next, the operation of this embodiment will be described with reference to the flow chart of FIG. 2 and the time chart of FIG.

First, when the engine is in operation, the oil pump 2 of the hydraulic power source device 1 is rotationally driven by its power, and the main port 3 constantly supplies oil to the secondary control valve 20 to generate a predetermined secondary pressure Ps. Further, with the secondary pressure Ps as a source pressure, the lubricating control valve 22 produces a constant lubricating pressure Po and the primary control valve 24 produces a primary pressure Pp according to the gear ratio i. At this time, in the control unit 40, the port flow rate Qp of the main port 3 and the total used flow rate Qs are calculated, and both are compared and judged.

Therefore, when the used flow rate Qs becomes larger than the port flow rate Qp as in the case of acceleration at low speed running,
When the switching OFF is determined, a switching signal is output to the switching control valve 12 at a predetermined switching time point to. Therefore, the switching control valve 1
2 shuts off the lubricating pressure Po, operates the switching valve 10 to the shut-off position, shuts off the oil from the sub-port 4, and adds the flow rate to the secondary control valve 20 and the like via the check valve 9 and supplies it. , The sub-port 4 is also operated under load. In this way, the port flow rate Qp is doubled and supplied to each part without any shortage.

On the other hand, at this time, the process proceeds from S1 to S2 and S3 in the flowchart of FIG.
The depressurized amount of s-Ps and the time points t1 and t2 at which the depressurization starts and ends are set. Then, as shown in FIG. 3B, a pressure reduction signal is output to the secondary control unit 46 at the pressure reduction start time point t1 before the switching time point to, and the secondary control valve 20 is caused to have the pressure reduction amount-
Pressure reduction control is performed in advance for Ps. Therefore, the sub-port flow rate is increased in the depressurized state, the oil hammer as indicated by the one-dot chain line at the time of increase is absorbed and mitigated, and the secondary pressure Ps changes smoothly as shown by the solid line.

Also, during steady running at high speed, the port flow rate Qp
When it becomes larger, it is judged that the switching is ON. In this case, the switching control valve 12 introduces the lubricating pressure Po to the switching valve 10 and operates to the communication position to return the discharge flow rate of the sub-port 4 to the suction side and not to operate. Drive under load. Therefore, the port flow rate Qp is halved, and the port load is reduced.

On the other hand, at this time, the process proceeds from S1 to S4 and S5 in the flowchart of FIG.
The pressure increase amount of s + Ps and time points t1 and t2 at which pressure increase starts and ends are set.

Then, as shown in FIG. 3A, a pressure increase signal is output to the secondary control section 46 at the pressure increase start time t1 before the switching time to, and the secondary control valve 20 is made to have the pressure increase amount +
The pressure increase control is performed by Ps in advance. Therefore, in the increased pressure state, the sub-port flow rate is reduced, and the pressure drop as indicated by the one-dot chain line during the reduction is absorbed and alleviated. Similarly, the secondary pressure Ps changes smoothly as indicated by the solid line.

A second embodiment of the present invention shown in FIG. 4 will be described. In this case, the check valve 9 has a pressure chamber 9c on the side opposite to the check ball 9b of the spring 9a, and the set load is variable. It The pressure chamber 9c of the check valve 9 is configured to communicate with the switching control valve 12 and the oil passage 11 of the switching valve 10 by the oil passage 15 having the throttle 14.

Therefore, in this embodiment, when the switching control valve 12 introduces the lubricating pressure Po into the switching valve 10 at the time of switching ON, the lubricating pressure Po is also introduced into the pressure chamber 9c of the check valve 9 and is closed. Increase the set load in the direction. Therefore, the check valve 9 is closed first, and the secondary pressure Ps of the oil passage 7 is set.
After securing the pressure, the discharge flow rate of the sub-port 4 is released and the operation is in a no-load operation state.
The drop of s is reduced.

A third embodiment of the present invention shown in FIG. 5 will be described. In this case, in the switching valve 10, for example, a notch 10d is formed in a land 10c for opening the drain port 10b of the spool 10a, and as shown in FIG. The opening area of the switching valve 10 at the beginning of opening is set small.

Therefore, in this embodiment, when the discharge flow rate of the sub-port 4 is drained by the switching valve 10 when the switching is turned on, the oil is gradually drained by the notch 10d, and the drop of the secondary pressure Ps is similarly reduced.

The embodiment of the present invention has been described above, but the present invention is not limited to this. For example, the switching signal itself provided to the switching control valve 12 may be changed so as to reduce the pressure fluctuation. Further, the invention can be similarly applied to the case where a plurality of independent oil pumps are provided as the hydraulic power source device.

[0027]

As described above, according to the present invention,
In the control of pump discharge pressure for variably controlling the pump capacity, by switching at least one of the oil pump means having a plurality of discharge ports so as to communicate with or cut off from the suction side,
Controlled to reduce oil hammer and pressure drop when switching pump capacity, prevent overload, deterioration of durability, noise and shock, and also prevent slipping of belt and clutch in case of continuously variable transmission. can do.

In the first embodiment, the switching time of the switching valve is electrically judged, and the pressure control valve is pressure-increased or decompressed at a predetermined timing so as to absorb the pressure drop or the oil hammer. Since it is controlled, the pressure fluctuation can be appropriately mitigated. Further, in the second and third embodiments, the pressure drop can be prevented with a simple mechanical structure.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of a pump discharge pressure control device of the present invention.

FIG. 2 is a flowchart of the operation when switching the pump capacity.

3 (a) and 3 (b) are time charts when switching the pump capacity.

FIG. 4 is a configuration diagram of a second embodiment of the present invention.

FIG. 5 is a diagram showing a third embodiment of the present invention.

FIG. 6 is a diagram showing characteristics of a switching valve.

[Explanation of symbols]

1 Hydraulic power source device 2 oil pump 3 main ports 4 sub ports 9 check valves 10 switching valve 12 Switching control valve 20 Secondary control valve 40 control unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor, Koji Sato             1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji             Heavy Industry Co., Ltd.

Claims (5)

[Claims] 1. An oil pump means having a plurality of discharge ports has one discharge side communicated with a pressure control valve which constantly regulates pressure, and the other discharge side communicated with a pressure control valve via a check valve. In addition, in the hydraulic power source device that communicates with the suction side through the switching valve, a mitigating means for temporarily mitigating the pressure fluctuation of the pressure control valve at the time of switching the switching valve from at least the cut-off position to the communication position is provided. A pump discharge pressure control device. 2. The mitigating means electrically determines whether the switching valve is switched from one of the shut-off position and the communication position to the other in the control unit, and the pressure of the pressure control valve is preliminarily increased or reduced at this switching time. The pump discharge pressure control device according to claim 1, wherein: 3. The control unit electrically sets, by various elements, a start time point and a finish time point of the pressure increase amount or the pressure decrease amount, the pressure increase before and after the switching time, and the like. Pump discharge pressure control device. 4. The mitigating means comprises a check valve of a variable set load type, and the working pressure acting on the switching valve when the switching valve is switched from the cut-off position to the communication position is also applied to the check valve in advance. The pump discharge pressure control device according to claim 1, wherein the control device is configured to be closed. 5. The pump discharge pressure control device according to claim 1, wherein the mitigating means is provided with a notch for setting the flow rate at the initial stage of switching to a small value on one of the spool and the port of the switching valve.