Oil pressure circuit of transmission

Abstract

The invention provides an oil pressure circuit of a transmission, which can prevent insufficient oil pressure supplied to a control object and effectively suppress oscillation phenomenon caused by frequent switching between high-pressure mode and low-pressure mode. The oil pressure circuit of the transmission includes: a one-way valve (V8), inserted between the main pump (PM) and the auxiliary pump (PS), when the discharge pressure of the auxiliary pump (PS) is higher than that of the main pump (PM) The valve is opened when the discharge pressure is high; and the fourth oil circuit (L4) is supplied to the discharge pressure of the main pump (PM) and the auxiliary pump (PS); and is conducted through the solenoid valve (V5), or the fourth oil circuit (L4) oil pressure becomes below the specified value to cut off the communication between the first oil passage (L1) and the second oil passage (L2) switched by the switching valve (V2), on the other hand, only through the solenoid valve (V5) The first oil passage (L1) switched by the switching valve (V2) is disconnected to communicate with the second oil passage (L2).

Description

technical field [0001] The present invention relates to a hydraulic circuit of a transmission, in particular, to a hydraulic circuit comprising a main pump and a subpump, configured to supply oil ejected from the main pump to a transmission control system, and to supply oil ejected from the sub pump to a transmission control system. The output oil is supplied to the oil pressure circuit of the transmission of the lubrication system. Background technique [0002] Conventionally, as a hydraulic circuit of a transmission mounted on a vehicle, for example, as shown in Patent Document 1, there are a main pump and an auxiliary pump simultaneously driven by an engine to supply oil to a sheave oil chamber of the transmission, a torque converter ( torqueconverter) and the hydraulic circuit of the lubrication system. In the hydraulic circuit disclosed in Patent Document 1, it is possible to switch between a low-pressure mode (lubrication mode) in which the discharge pressure of the s...

AI Technical Summary

Problems solved by technology

[0004] However, if the above-mentioned switching conditions between the high-voltage mode and the low-voltage mode are fixed, a so-called hunting phenomenon in which the low-voltage mode and the high-voltage mode are frequently switched may occur.

That is, there may be a phenomenon in which the following processes are repeated: transient internal pressure drop of the torque converter → automatic switching to the high-pressure mode → restoration of the internal pressure of the torque converter with sufficient line pressure → automatic switching to the low-voltage mode Switching → Transient internal pressure drop of the torque converter

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