JP2005163979A - Vehicle transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle transmission for improving feeling when engaging a clutch even if the temperature of hydraulic fluid is low or when an engine speed is low. <P>SOLUTION: An oil return pipe 11 for returning oil to an oil tank 3 is connected to the middle of a second hydraulic supply pipe 6 for supplying oil discharged from a hydraulic pump 2 to a torque converter 1 as hydraulic fluid, a pressure control valve 12 in which the operating pressure is controlled by a proportional electromagnetic type pressure control valve 13 is provided in the middle of the oil return pipe, a controller 17 for outputting a pressure command for instructing the operating pressure is provided in the proportional electromagnetic type pressure control valve, and the controller has a function for outputting a pressure command according to the speed of an engine and oil temperature by inputting each measurement value from an engine tachometer 16 for detecting the speed of the engine and an oil temperature meter 15 for detecting oil temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transmission for a vehicle.

  Normally, a transmission for an industrial vehicle, for example, a wheel loader, is provided with a torque converter between the engine side and the transmission side, and hydraulic oil for a clutch in the transmission is supplied to the transmission by a hydraulic pump. At the same time, the hydraulic fluid from the hydraulic pump is guided to the torque converter.

Here, a hydraulic circuit for supplying hydraulic oil to the transmission and the torque converter will be described with reference to the drawings.
As shown in FIG. 2, a hydraulic pump 51 driven by an engine (not shown) supplies oil in an oil tank 52 as hydraulic oil to a clutch portion of a transmission (T / M) (not shown). A first hydraulic pressure supply pipe 53 is provided, and a second hydraulic pressure supply pipe 55 that supplies the oil to the torque converter 54 as hydraulic oil is connected in the middle thereof.

  On the second hydraulic pressure supply pipe 55 side, a pressure adjusting valve 56 is provided for adjusting the pressure of the hydraulic oil supplied to the clutch portion (pressure in the first hydraulic pressure supply pipe) to be a set pressure. When the set pressure is exceeded, the oil is released to the second hydraulic pressure supply pipe 55 side.

  In addition, a safety valve (also referred to as a safety valve) 57 is interposed in the vicinity of the torque converter 54 of the second hydraulic pressure supply pipe 55, and when the set pressure is exceeded, the oil in the second hydraulic pressure supply pipe 55 is discharged. An oil return pipe 58 is connected to protect the torque converter 54 by returning it to the oil tank 52.

  The hydraulic oil discharged from the torque converter 54 is supplied as lubricating oil to the clutch portion of the transmission through a third hydraulic pressure supply pipe 62 in which an oil cooler 61 is interposed.

  In the above configuration, when the wheel loader is in operation, the oil in the oil tank 52 is supplied to the transmission side as hydraulic oil for the clutch portion via the first hydraulic pressure supply pipe 53 by driving the hydraulic pump 51. The oil pressure is adjusted to be equal to or lower than the pressure set by the pressure adjustment valve 56 provided on the second hydraulic pressure supply pipe 55 side.

  When the pressure of the oil supplied to the transmission side exceeds the set pressure of the pressure regulating valve 56, the oil flows into the second hydraulic pressure supply pipe 55 side and is supplied to the torque converter 54 as working oil.

  The oil supplied to the torque converter 54 is supplied as a lubricating oil to the clutch portion of the transmission through the oil cooler 61 and finally returned to the oil tank 52. Note that at least the pressure loss (back pressure) in the oil cooler 61 generates a necessary pressure in the torque converter 54. If the pressure loss due to the oil cooler 61 alone is insufficient, the oil cooler 61 A throttle valve is provided on the downstream side.

By the way, when the operation is started or when the temperature of the hydraulic oil is low, surge pressure may be generated, and the pressure of the hydraulic oil in the torque converter 54 may be abnormally high. The safety valve 57 was opened and the oil was returned from the oil return pipe 58 into the oil tank 52 (see Non-Patent Document 1).
"TCM Service Manual Wheel Loader" (see Figure 2.23 on page 50) issued by Toyo Hakko Co., Ltd. in July 1997.

By the way, when the temperature of the hydraulic oil is low at the start of operation or normal operation, a surge pressure is generated and the pressure of the hydraulic oil in the torque converter 54 increases.
When the hydraulic oil pressure increases, the absorption torque (transmittable torque) in the torque converter 54 increases, and therefore, a shock generated on the torque converter 54 side is added to the shock when the clutch is engaged during a shift operation. There was a problem that the feeling when connecting them was bad. The same was true when the engine speed was low.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle transmission that can improve the feeling when the clutch is engaged even when the oil temperature is low or the engine speed is low.

In order to solve the above problems, a vehicle transmission according to claim 1 of the present invention is a vehicle transmission in which a torque converter is disposed between an engine and a transmission,
An oil return pipe that returns oil to the oil tank side is connected in the middle of the hydraulic oil supply pipe that supplies oil discharged from the hydraulic pump as hydraulic oil to the torque converter, and a proportional electromagnetic type is connected in the middle of the oil return pipe. A pressure adjusting valve whose operating pressure is controlled by a pressure control valve, a controller for outputting a pressure command for instructing the operating pressure to the proportional electromagnetic pressure control valve;
And in the controller,
In a predetermined time after the start of operation, the proportional electromagnetic pressure control valve is provided with a pressure increasing function for raising the pressure regulating valve from the open state to a predetermined pressure,
Input each detection value from the speed detector that detects the engine speed and / or the temperature detector that detects the oil temperature in the oil tank, and issue a pressure command according to the engine speed and / or oil temperature. It has a function to output.

A vehicle transmission according to claim 2 is the transmission according to claim 1,
When the temperature of the hydraulic oil is low and / or when the engine speed is low, an operating pressure lower than the reference set pressure in the pressure regulating valve is output from the controller as a pressure command.

  According to the above configuration, the operating pressure of the pressure regulating valve capable of controlling the pressure in the torque converter is an appropriate value from the controller to the proportional electromagnetic pressure control valve according to the temperature of the hydraulic oil and / or the engine speed. For example, when the temperature of the hydraulic oil is low, the operating pressure is lowered to reduce the amount of oil supplied to the torque converter (specifically, the torque converter By reducing the amount of oil that passes through an oil cooler disposed downstream of the oil cooler, the oil temperature can be quickly adjusted to an appropriate oil temperature, and therefore, the shock that occurs during the shifting operation can be reduced and a good feeling can be obtained. Even when the engine speed is low, by reducing the operating pressure and reducing the absorption torque in the torque converter, it is possible to reduce the shock generated during the shift operation and obtain a good feeling.

  In addition, immediately after the start of operation, the operating pressure in the pressure regulating valve is gradually increased via the proportional electromagnetic pressure control valve by the pressure increasing function provided in the controller for a predetermined time set in advance. Abnormal pressure is prevented from being generated in the torque converter at the start of operation, and thus the torque converter can be protected.

[Embodiment]
A vehicle transmission according to an embodiment of the present invention will be described below with reference to FIG.
In the present embodiment, a description will be given of a transmission device for a wheel loader in which a torque converter is provided between an engine and a transmission.

  As shown in FIG. 1, the transmission is driven by an engine and a transmission (T / M) (not shown), a torque converter 1 disposed between them, and an engine in the middle. A first hydraulic supply pipe 4 that is provided with a hydraulic pump 2 and supplies oil in an oil tank (also a T / M casing) 3 as hydraulic oil to a clutch portion on the transmission side, and the first hydraulic supply pipe 4 Is connected to the downstream side of the hydraulic pump 2 and a pressure control valve (for example, a relief valve is used) 5 is interposed on the way, and oil discharged from the hydraulic pump 2 is supplied to the torque converter 1 as hydraulic oil. And a second oil pressure supply pipe (hydraulic oil supply pipe) 6 and an oil cooler 7 provided in the middle of the oil, and the oil discharged from the torque converter 1 is supplied to the clutch portion as lubricating oil. A third hydraulic supply pipe 8 for performing the operation, an oil return pipe 11 connected to the second hydraulic supply pipe 6 for returning the oil in the second hydraulic supply pipe 6 to the oil tank 3, and the oil return pipe 11 is a pressure adjusting valve for adjusting the pressure of oil in the second hydraulic pressure supply pipe 6 that is interposed in the middle of the pipe 11 and connected to the upstream side of the oil return pipe 11 based on a pressure command from the outside (the operation pressure thereof). And a pressure control valve 12 based on the pressure command (specifically, a pressure value equivalent to the pressure command). A proportional electromagnetic pressure control valve 13 for outputting pressure, a hydraulic pressure gauge (hydraulic detector) 14 provided on the inlet side of the torque converter 1 for detecting the hydraulic pressure in the second hydraulic pressure supply pipe 6, and the oil tank 3 An oil temperature gauge (oil temperature detector) 15 for detecting the oil temperature inside the engine, and an engine An engine tachometer (rotation number detector) 16 for detecting the number of revolutions and a measured value (detection value) from each of the instruments 14 to 16 are inputted, and an appropriate value of oil pressure in the second hydraulic pressure supply pipe 6, that is, torque A controller (also referred to as a controller) 17 that calculates an appropriate value of pressure at the inlet of the converter 1 and outputs a pressure command (corresponding to an external pressure command) that is the appropriate value to the proportional electromagnetic pressure control valve 13; It is composed of Note that the hydraulic oil in the first hydraulic supply pipe 4 is supplied to the hydraulic inlet port of the proportional electromagnetic pressure control valve 13 through the fourth hydraulic supply pipe 18, and the hydraulic outlet port and the pressure adjustment valve 12 is connected via a fifth hydraulic pressure supply pipe 19, and the operation generated by the proportional electromagnetic pressure control valve 13 based on the pressure command from the controller 17 via the fifth hydraulic pressure supply pipe 19. The hydraulic pressure for operation having pressure is supplied to the pressure regulating valve 12.

  The appropriate values (the pressure command and the operating pressure) obtained by the controller 17 are determined in consideration of the pressure loss because the pressure loss generated in the torque converter 1 and the oil cooler 7 can be grasped in advance. .

  For example, when the oil temperature is low, the operating pressure is set lower than the reference set pressure (which is set to protect the torque converter during normal operation), while when the oil temperature is high The operating pressure is set higher than the reference set pressure. That is, when the oil temperature in the torque converter 1 is low, the amount of oil flowing through the oil cooler 7 by passing the oil through the oil return pipe 11 is reduced, and the appropriate oil temperature (for example, about 40 ° C.) is quickly reduced. On the contrary, when the oil temperature is high, the oil amount is passed through the oil return pipe 11 to increase the amount of oil flowing through the oil cooler 7, and the oil temperature is quickly adjusted to an appropriate oil temperature. As described above, by setting the temperature of the hydraulic oil supplied to the torque converter 1 to an appropriate temperature quickly, the shock generated during the gear shifting operation is reduced.

  When the engine speed is low, the operating pressure is set lower than the reference set pressure. On the other hand, when the engine speed is high, the operating pressure is set higher than the reference set pressure. Is done. By setting in this way, the pressure of the hydraulic oil supplied to the torque converter 1 is a pressure corresponding to the flow state of the hydraulic oil in the torque converter 1 rotated by the engine, that is, in the torque converter 1. In this case, since the absorption torque is in accordance with the engine speed, the shock generated during the shift operation is reduced.

  Further, the controller 17 waits for the proportional electromagnetic pressure control valve 13 to wait for the pressure regulating valve 12 (pressure release state) for a predetermined time (for example, about several seconds) after the operation of the wheel loader is started. ) To a reference set pressure, and a boosting function for outputting a boost command (also a pressure command) is provided. Thus, since the operating pressure at the pressure regulating valve 12 is gradually increased from the standby state to the reference set pressure at the start of operation, an abnormal pressure is generated in the torque converter 1 at the start of operation. Generation of (high pressure) is prevented. For example, when the reference set pressure value (pressure value determined to be high for safety measures during normal operation) is fixed, the pressure rises at least to the reference set pressure value in the torque converter 1. The absorption torque is inevitably high, and the shock cannot be suppressed. The hydraulic pressure gauge 14 monitors the generation of abnormal pressure at low temperatures and the control state related to pressure.

  Next, the operation of the transmission will be described. During operation of the wheel loader, the operation in the torque converter 1 is detected by detecting the temperature of the hydraulic oil, the engine speed, and the pressure of the hydraulic oil supplied to the torque converter. The oil pressure is adjusted so that the feeling during the shifting operation, that is, the clutch engagement operation is good.

  In other words, immediately after the start of operation, the proportional electromagnetic pressure control valve 13 is set in the standby state at the pressure regulating valve 12 by the pressure increasing function provided in the controller 17 for a predetermined time set in advance, for example, for a few seconds. The pressure increase command is output so that the pressure gradually increases from the (non-operating state) to the reference set pressure, and therefore the operating pressure is gradually increased to the reference set pressure in the pressure adjustment valve 12.

  Thus, at the start of operation, the pressure is gradually increased when the hydraulic oil in the second hydraulic pressure supply pipe 6 is released, so that the pressure in the torque converter 1 is prevented from becoming abnormally high. That is, the torque converter 1 can be protected (a function equivalent to the function of the safety valve is obtained).

On the other hand, during normal operation of the wheel loader, the pressure of the hydraulic oil supplied to the torque converter 1 is controlled based on the oil temperature gauge 15, the engine tachometer 16 and the oil pressure gauge 14.
For example, when the oil temperature is low, the operating pressure is set lower than the reference set pressure, whereas when the oil temperature is high, the operating pressure is set higher than the reference set pressure. That is, when the oil temperature in the torque converter 1 is low, the amount of oil passing through the oil return pipe 11 through a large number of eyes and flowing to the oil cooler 7 is reduced, so that the appropriate oil temperature is quickly achieved. On the contrary, when the oil temperature is high, the amount of oil flowing through the oil cooler 7 is increased by passing the oil through the oil return pipe 11 little by little, and the oil temperature is quickly adjusted to the appropriate oil temperature. In this way, by setting the temperature of the hydraulic oil supplied to the torque converter 1 to an appropriate temperature quickly, the shock generated at the time of the shifting operation is reduced, and a good feeling can be obtained.

  When the engine speed is low, the operating pressure is set lower than the reference set pressure. On the other hand, when the engine speed is high, the operating pressure is set higher than the reference set pressure. By setting in this way, the pressure of the hydraulic oil supplied to the torque converter 1 becomes a pressure corresponding to the flow state of the hydraulic oil in the torque converter 1 rotated by the engine, that is, in the torque converter 1. Since the absorption torque according to the engine speed is obtained, the shock generated during the shifting operation is reduced, and thus a good feeling can be obtained.

  Furthermore, an appropriate operating pressure at the pressure regulating valve 12 may be indicated based on both the temperature of the hydraulic oil and the engine speed. In this case, a low indicated operating pressure is used.

  As described above, the pressure of the hydraulic oil in the torque converter 1 is adjusted based on the temperature of the hydraulic oil and the rotational speed of the engine. This is because it depends on the pressure loss and is greatly affected by the oil temperature and its flow rate (engine speed).

1 is a hydraulic circuit diagram showing a schematic configuration of a vehicle transmission according to an embodiment of the present invention. It is a hydraulic circuit diagram which shows schematic structure of the transmission of the vehicle concerning a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque converter 2 Hydraulic pump 4 1st hydraulic supply pipe 5 Pressure control valve 6 2nd hydraulic supply pipe 11 Oil return pipe 12 Pressure adjustment valve 13 Proportional electromagnetic pressure control valve 14 Hydraulic gauge 15 Oil temperature gauge 16 Engine tachometer 17 Control vessel

Claims (2)

A transmission for a vehicle in which a torque converter is disposed between an engine and a transmission,
An oil return pipe that returns oil to the oil tank side is connected in the middle of the hydraulic oil supply pipe that supplies oil discharged from the hydraulic pump as hydraulic oil to the torque converter, and a proportional electromagnetic type is connected in the middle of the oil return pipe. A pressure adjusting valve whose operating pressure is controlled by a pressure control valve, a controller for outputting a pressure command for instructing the operating pressure to the proportional electromagnetic pressure control valve;
And in the controller,
In a predetermined time after the start of operation, the proportional electromagnetic pressure control valve is provided with a pressure increasing function for raising the pressure regulating valve from the open state to a predetermined pressure,
Input each detection value from the speed detector that detects the engine speed and / or the temperature detector that detects the oil temperature in the oil tank, and issue a pressure command according to the engine speed and / or oil temperature. A vehicle transmission device characterized by having a function of outputting. When the temperature of the hydraulic oil is low and / or when the engine speed is low, an operating pressure lower than the reference set pressure in the pressure regulating valve is output from the controller as a pressure command. The transmission of a vehicle according to claim 1.

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