JP3916181B2 - Hydraulic clutch control device for transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulically operated clutch (hydraulic clutch) that is provided in a transmission and controls power transmission through the transmission, and more particularly to a hydraulic clutch control device that controls engagement of the hydraulic clutch. .
[0002]
[Prior art]
The transmission shifts and transmits the output of the engine (drive source), and is configured by combining a transmission mechanism that performs such a shift and a torque converter or a starting clutch. Here, as a type of transmission that combines a transmission mechanism and a starting clutch, for example, there is a continuously variable transmission, and in the continuously variable transmission, the engagement control of the starting clutch depends on the accelerator opening, the engine speed, and the like. Automatically controlled.
[0003]
As an apparatus for performing such engagement control, for example, there is an apparatus disclosed in Japanese Patent Laid-Open No. 6-117530. This device was invented by the present applicant, and a continuously variable transmission in which a V-belt continuously variable transmission mechanism and a starting clutch are combined is disclosed, and a device for controlling the engagement of the starting clutch is disclosed. Yes. In this apparatus, basically, the clutch control pressure supplied to the starting clutch (hydraulic clutch) is regulated by an electromagnetic pressure regulating valve (clutch control valve). However, a Pitot regulator valve that creates a Pitot pressure corresponding to the engine rotation is also provided. When the electrical control system fails, the Pitot pressure is supplied to the starting clutch, and a certain amount of starting clutch engagement control is performed by the Pitot pressure. Is configured to be possible. That is, the Pitot pressure is used as a control backup in the event of an electrical failure. In addition, an inhibitor solenoid valve is separately installed for use as a control backup in this way.
[0004]
Japanese Patent Laid-Open No. 1-295067 discloses a continuously variable transmission in which a V-belt type continuously variable transmission mechanism and a torque converter are combined, and a forward clutch for performing forward / reverse switching in the continuously variable transmission, An example of selectively using the clutch control pressure and the Pitot pressure regulated by a duty solenoid valve as the working hydraulic pressure of the reverse brake is disclosed. That is, an example in which the Pitot pressure is used as a shift control hydraulic pressure is disclosed. Here, the pitot pressure is used when the oil temperature is low, and the pressure is controlled by the duty solenoid valve when the oil temperature is higher than the predetermined temperature. When the oil viscosity is low and the oil viscosity is high, the duty control is avoided and stable clutch engagement control is performed. I try to do it.
[0005]
In this way, several systems have been proposed that use both control oil pressure and pitot pressure obtained by using electromagnetic control valves, etc., all of which are only for electrical failures or when the oil temperature is low. Only the Pitot pressure is used, and usually clutch engagement control or the like is performed using a control hydraulic pressure by an electromagnetic control valve.
[0006]
[Problems to be solved by the invention]
For this reason, the conventional device requires a switching valve for selectively supplying the control hydraulic pressure and the Pitot pressure regulated by the electromagnetic control valve to the clutch, and a solenoid valve for controlling the operation of the switching valve. There is a problem that the configuration of the control device is complicated and the device cost tends to increase. In addition, the Pitot pressure is only used in special cases such as when an electrical failure occurs or when the oil temperature is low. Normally, the pressure is adjusted by the electromagnetic control valve. There is also a problem that it is necessary to always drive and control the power consumption.
[0007]
The present invention has been made in view of such a problem, and it is possible to appropriately select the control hydraulic pressure and the Pitot pressure regulated by the electromagnetic control valve and supply them to the hydraulic clutch, and the apparatus configuration is simple and An object of the present invention is to provide a hydraulic clutch control device that can reduce the power consumption of an electromagnetic control valve.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, a transmission hydraulic clutch control device according to the present invention includes a line pressure supply source that generates a line pressure and a pitot pressure supply source that generates a pitot pressure corresponding to the drive rotational speed of the transmission. And a clutch control valve that selectively supplies the line pressure and the Pitot pressure to the hydraulic clutch. The clutch control valve is actuated by receiving a control current, and the control current is greater than a specified current. When it is low, the Pitot pressure is supplied to the hydraulic clutch, and when the control current is higher than the specified current, the line pressure is adjusted according to the control current to generate the clutch control pressure and this clutch control pressure is supplied to the hydraulic clutch. The
[0009]
In the hydraulic clutch control device having such a configuration, the control for selecting and supplying either the pitot pressure or the clutch control hydraulic pressure to the hydraulic clutch only by controlling the current value flowing through the clutch control valve, and the supply in this way. It is possible to perform all the clutch control hydraulic pressure adjustment control. That is, since these control functions can be performed by only one clutch control valve, the configuration of the control device is simplified and the device cost is reduced.
[0010]
When this transmission is used for a vehicle, when starting the vehicle, a control current higher than a specified current is supplied to the clutch control valve to supply a clutch control pressure corresponding to the control current to the hydraulic clutch. When the vehicle is stopped and during steady running, it is preferable to supply a pitot pressure to the hydraulic clutch by supplying a control current lower than a specified current to the clutch control valve.
[0011]
When starting a vehicle, smooth start control is required, and fine and delicate engagement of the hydraulic clutch is required. Therefore, fine control is performed by supplying control hydraulic pressure to the hydraulic clutch in accordance with the control current flowing through the clutch control valve. Can be performed. On the other hand, at the time of stopping and steady running, fine control is not required, so that sufficient control can be performed only by performing hydraulic clutch engagement control using the Pitot pressure. At this time, since the control current supplied to the clutch control valve is low (lower than the specified current), the power consumption of the clutch control valve can be suppressed. In view of the above, when the vehicle is stopped and during steady running, the control current flowing through the clutch control valve is set to zero and the pitot pressure is supplied to the hydraulic clutch in order to reduce power consumption. Most preferred.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 and 2 show the configuration of a continuously variable transmission having a hydraulic clutch control device according to the present invention. This continuously variable transmission is a belt type continuously variable transmission using a metal V belt, and this belt type continuously variable transmission CVT is a metal V belt mechanism disposed between an input shaft 1 and a counter shaft 2. 10 and a planetary gear type forward / reverse switching mechanism 20 disposed between the input shaft 1 and the drive-side movable pulley 11, and the counter shaft 2 and the output-side member (differential mechanism 8 or the like). The main clutch 5 is provided. The continuously variable transmission CVT is used for a vehicle, the input shaft 1 is connected to the output shaft of the engine ENG via a coupling mechanism CP, and the power transmitted to the differential mechanism 8 is transmitted to the left and right wheels. .
[0013]
The metal V-belt mechanism 10 is wound between a drive-side movable pulley 11 disposed on the input shaft 1, a driven-side movable pulley 16 disposed on the counter shaft 2, and both pulleys 11, 16. It consists of a metal V-belt 15.
[0014]
The drive-side movable pulley 11 includes a fixed pulley half 12 that is rotatably disposed on the input shaft 1, and a movable pulley half 13 that can move relative to the fixed pulley half 12 in the axial direction. . On the side of the movable pulley half 13, a drive side cylinder chamber 14 is formed surrounded by a cylinder wall 12 a coupled to the fixed pulley half 12, and the hydraulic pressure supplied into the drive side cylinder chamber 14 A side pressure is generated to move the movable pulley half 13 in the axial direction.
[0015]
The driven movable pulley 16 includes a fixed pulley half 17 fixed to the counter shaft 2 and a movable pulley half 18 that can move relative to the fixed pulley half 17 in the axial direction. A driven-side cylinder chamber 19 is formed on the side of the movable pulley half 18 by being surrounded by a cylinder wall 17 a coupled to the fixed pulley half 17, and is driven by hydraulic pressure supplied into the driven-side cylinder chamber 19. A side pressure is generated that moves the movable pulley half 18 in the axial direction.
[0016]
Therefore, by appropriately controlling the hydraulic pressure supplied to both the cylinder chambers 14 and 19, an appropriate pulley side pressure that does not cause the belt 15 to slip is set, and the pulley widths of the pulleys 11 and 16 are changed. As a result, the winding ratio of the V-belt 15 can be changed to change the transmission gear ratio steplessly.
[0017]
The planetary gear type forward / reverse switching mechanism 20 has a double pinion type planetary gear train, its sun gear 21 is coupled to the input shaft 1, the carrier 22 is coupled to the stationary pulley half 12, and the ring gear 23 is fixed by the reverse brake 27. It can be held. Further, the forward clutch 25 that can connect the sun gear 21 and the ring gear 23 is provided. When the forward clutch 25 is engaged, all the gears 21, 22, and 23 rotate integrally with the input shaft 1, and the drive pulley 11 Are driven in the same direction (forward direction) as the input shaft 1. On the other hand, when the reverse brake 27 is engaged, the ring gear 23 is fixedly held, so that the carrier 22 is driven in the opposite direction to the sun gear 21 and the drive pulley 11 is in the opposite direction (reverse direction) to the input shaft 1. ).
[0018]
The main clutch 5 is a clutch for controlling the power transmission between the counter shaft 2 and the output side member. During the engagement, the power transmission between the two is possible, and the engagement force is controlled to control the input side. The torque transmission capacity (torque capacity) with the output side can also be controlled. For this reason, when the main clutch 5 is engaged, the engine output changed by the metal V-belt mechanism 10 is transmitted to the differential mechanism 8 via the gears 6a, 6b, 7a, 7b. It is divided and transmitted (not shown). When the main clutch 5 is disengaged (torque capacity is zero), this power transmission cannot be performed and the transmission is in a neutral state.
[0019]
The control device according to the present invention controls the engagement of the main clutch 5, and the configuration of the hydraulic device for the control will be described with reference to FIG. 3 and FIG. In this circuit diagram, circled numbers {circle around (1)} are connected, and a cross indicates that the portion is connected to the drain.
[0020]
The oil discharged from the hydraulic pump 30 is supplied to the high pressure regulator valve 41 through the oil passage 32 and is supplied to the reducing valve 58 through the oil passage 36. The reducing valve 58 generates a line pressure PMOD having a substantially constant oil pressure, and supplies hydraulic oil having this line pressure to the oil passages 37a, 37b, 37c, 31a.
[0021]
The oil passage 37 a is connected to the high / low pressure control valve 45. The high / low pressure control valve 45 has a linear solenoid 45a. The energization current to the linear solenoid 45a is controlled, and the pressing force acting on the spool 45b from the linear solenoid 45a is controlled, so that the high / low pressure control valve 45 is supplied from the oil passage 37a. The line pressure PMOD is adjusted, and the control back pressure PHLC corresponding to the pressing force is supplied to the oil passages 35a and 35b. This control back pressure PHLC is supplied to the right end oil chamber 43b of the low pressure regulator valve 43 through the oil passage 35a and acts to press the spool 43a to the left. The control back pressure PHLC is supplied to the right end oil chamber 47b and the first intermediate oil chamber 47c of the high pressure control valve 47 via the oil passage 35b, and acts to press the spool 47a leftward and rightward, respectively. To do.
[0022]
The high pressure regulator valve 41 regulates the hydraulic pressure supplied from the pump 30 through the oil passage 32, and supplies the high side pressure control pressure PH to the oil passages 33a and 33b. The high side pressure control pressure PH is supplied to the shift valve 53 via the oil passage 33a and also to the low pressure regulator valve 43 via the oil passage 33b. Further, the high side pressure control pressure PH is also supplied to the oil passage 33 c connected to the left end oil chamber 47 d of the high pressure control valve 47.
[0023]
An oil passage 37c to which the line pressure PMOD is supplied is connected to the second intermediate oil chamber 47e of the high pressure control valve 47. The oil passage 37c has an orifice 56 and is connected to the solenoid valve 55 on the downstream side of the orifice 56, and the supply control of the line pressure PMOD to the second intermediate oil chamber 47e is performed by the on / off operation of the solenoid valve 55. The The high pressure control valve 47 controls the position of the spool 47a by the control back pressure PHLC supplied to the right end oil chamber 47b and the first intermediate oil chamber 47c and the line pressure PMOD supplied to the second intermediate oil chamber 47e. The hydraulic pressure produced by adjusting the high side pressure control pressure PH supplied from 33c is supplied as back pressure to the right end oil chamber 41b of the high pressure regulator valve 41 through the oil passage 33d.
[0024]
The low pressure regulator valve 43 receives the control back pressure PHLC, adjusts the high side pressure control pressure PH supplied from the oil passage 33 b, and supplies the low side pressure control pressure PL to the oil passage 34. The low side pressure control pressure PL is supplied to the shift valve 53 via oil passages 34 a and 34 b branched from the oil passage 34.
[0025]
The shift control valve 51 has a linear solenoid 51a, and the current supplied to the linear solenoid 51a is controlled, and the pressing force acting on the spool 51b from the linear solenoid 51a is controlled, so that the shift control valve 51 is supplied from the oil passage 37b. The line pressure PMOD is adjusted, and a shift control pressure PSV corresponding to this pressing force is supplied to the oil passage 38. This shift control pressure PSV is supplied to the left end oil chamber 53c of the shift valve 53, and acts to press the spool 53a to the right.
[0026]
The shift valve 53 performs control to appropriately distribute and supply the high and low side pressure control pressures PH and PL to the drive side and driven side cylinder chambers 14 and 19 via the oil passages 39a and 39b according to the position of the spool 53a. Here, the spool 53a is pushed leftward by the spring 53b, and is pushed rightward by receiving the shift control pressure PSV supplied to the left end oil chamber 53c. Therefore, the position of the spool 53a can be controlled by controlling the shift control pressure PSV. As a result, the oil pressure in the drive side and driven side cylinder chambers 14 and 19 is controlled to reduce the reduction ratio in the belt mechanism 10. Can be controlled in stages.
[0027]
On the other hand, the line pressure PMOD supplied from the reducing valve 58 to the oil passage 31a branches to the oil passages 31b, 31c, 31d and is supplied to the main clutch control valve 75, the manual valve 61, and the Pitot valve 70, respectively. The Pitot valve 70 is a valve that generates a Pitot pressure Ppt that is proportional to the engine rotation, and generates a Pitot pressure Ppt from the line pressure PMOD and supplies it to the oil passage 71.
[0028]
The main clutch control valve 75 has a linear solenoid 75a. The energization current to the linear solenoid 75a is controlled, and the pressing force acting on the spool 76 is controlled according to the energization current. The main clutch control valve 75 controls the hydraulic pressure supplied to the main clutch 5 to engage the main clutch. The apparatus of this part is related to the present invention, and will be described with reference to FIGS.
[0029]
First, when the energization current Is of the linear solenoid 75a is zero, the pressing force of the linear solenoid 75a is zero, and as shown in FIG. 5, the spool 76 is moved to the right by the urging force of the spring 77, and the oil passage 31b is spooled. The oil passage 71 communicates with the oil passage 72 through the groove 76 a of the spool 76 while being closed by the land portion 76. Therefore, the Pitot pressure Ppt from the Pitot valve 70 is supplied to the oil passage 72 and supplied to the main clutch 5 via the shuttle valve 74, and the engagement control of the main clutch 5 is performed by the Pitot pressure Ppt. As can be seen from this, the Pitot pressure Ppt produced by the Pitot valve 70 is a high-pressure hydraulic pressure that increases corresponding to the engine rotation and is capable of controlling the engagement of the main clutch 5.
[0030]
When the energizing current Is to the linear solenoid 75a is increased from this state, the leftward pressing force acting on the spool 76 from the linear solenoid increases, and the energizing current becomes larger than the specified current Is (1), as shown in FIG. Thus, the spool 76 is moved to the left by a predetermined amount by the pressing force of the linear solenoid, the oil passage 71 is closed by the land portion of the spool 76, and the supply of the pitot pressure Ppt is stopped. At the same time, the supply of the line pressure PMOD from the oil passage 31b to the oil passage 73 is controlled according to the leftward pressing force acting on the spool 76 from the linear solenoid 75a. That is, the line pressure PMOD supplied from the oil passage 31a is adjusted to generate a main clutch control pressure PSC corresponding to the pressing force in the oil passage 73. The main clutch control pressure PSC is supplied to the main clutch via the shuttle valve 74. The clutch 5 is supplied and its engagement control is performed.
[0031]
Thus, by making the energization current to the linear solenoid 75a equal to or less than the specified current Is (1), the engagement control of the main clutch 5 by the Pitot pressure Ppt can be performed, and the energization current to the linear solenoid 75 is also performed. Is appropriately controlled in a range higher than the specified current Is (1) to generate a main clutch control pressure PSC corresponding to the energization current and to perform engagement control of the main clutch 5 using the main clutch control pressure PSC. be able to.
[0032]
The relationship between the energization current Is to the linear solenoid 75a and the main clutch control hydraulic pressure PSC in this case is shown in FIG. As can be seen from this figure, when the energization current is equal to or less than the specified current Is (1), the pitot pressure Ppt is supplied to the main clutch 5 and its engagement is controlled. On the other hand, when the specified current Is (1) is exceeded, the main clutch control pressure PSC increases in proportion to the increase in the energization current, and the engagement control of the main clutch 5 can be performed by the control of the energization current.
[0033]
Here, since it is required to perform smooth vehicle start control by performing fine and accurate engagement control of the main clutch 5 at the time of vehicle start, the engagement control of the main clutch 5 at the time of vehicle start is performed by a linear solenoid. An energizing current exceeding the specified current Is (1) is supplied to 75a. On the other hand, when the vehicle is in a steady running state or when the vehicle is stopped, the fine current control is not required. Therefore, the energization current to the linear solenoid 75a is cut off (set to zero) and the pitot pressure Ppt is applied to the main clutch 5. To control the engagement. As a result, power consumption during steady running or when the vehicle is stopped is suppressed.
[0034]
A configuration as shown in FIG. 8 may be used in place of the engagement control configuration of the main clutch 5 using the main clutch control valve 75 having such a configuration. Here, the line pressure PMOD is adjusted by the bleed type linear solenoid valve 180 to create a control pressure Pc, and the operation of the main clutch control valve 175 is controlled by this control pressure Pc. The main clutch control valve 175 is configured to have a spool 176 that is always urged to the left by a spring 177 and is urged to the right by receiving a control pressure Pc from the oil passage 181. In the main clutch control valve 175, the control pressure Pc becomes maximum when the energizing current Is of the linear solenoid valve 180 is zero, and the control pressure Pc decreases as the energizing current Is increases.
[0035]
Therefore, as shown in FIG. 9, when the energizing current Is of the linear solenoid valve 180 is equal to or lower than the specified current Is (2), the control pressure Pc becomes equal to or higher than the specified pressure Pc (2), and the spool 176 is moved to the right to move the oil. Pitot pressure Ppt is supplied from the passage 71 to the oil passage 72, and this pitot pressure Ppt is supplied to the main clutch 5 via the shuttle valve 74. On the other hand, when the energizing current Is of the linear solenoid valve 180 is equal to or greater than the specified current Is (2), the control pressure Pc is equal to or less than the specified pressure Pc (2) and corresponds to the energized current Is, and the spool 176 is moved to the left. The line pressure PMOD of the oil passage 31b is adjusted according to the control pressure Pc to supply the main clutch control pressure PSC to the oil passage 73, and this main clutch control pressure PSC is supplied to the main clutch 5 via the shuttle valve 74. To do.
[0036]
That is, even if the configuration as shown in FIG. 8 is used, the Pitot pressure Ppt can be supplied to the main clutch 5 according to the energization current, or the main clutch control pressure PSC can be generated and supplied. However, also in this case, the engagement control of the main clutch 5 at the start of the vehicle is performed using the main clutch control pressure PSC by passing an energization current exceeding the specified current Is (2) through the linear solenoid 75a. When the vehicle is in a steady running state or when the vehicle is stopped, the energization current to the linear solenoid 75a is cut off (set to zero), and the Pitot pressure Ppt is supplied to the main clutch 5 to control its engagement, thereby consuming power. Suppress. In this example, a duty control solenoid valve may be used instead of the linear solenoid valve 180.
[0037]
Here, returning to FIG. 3 again, the manual valve 61 is connected to a shift lever of a driver's seat (not shown) via a control cable, and is operated by a driver's manual operation. As the manual operation positions, there are six positions of P, R, N, D, S, and L, and the spool 61a of the manual valve 61 is moved to the corresponding position shown in the figure according to the operation positions. In the figure, the spool 61a is in the N (neutral) position. The first oil chamber 61 b of the manual valve 61 is directly connected to the forward clutch 25 via an oil passage 64, and the second oil chamber 61 c is connected to the reverse brake control valve 65 via an oil passage 63. Note that an oil passage 67 connected to the reverse brake 27 is connected to the reverse brake control valve 65.
[0038]
The manual valve 61 connects the oil passage 63 and the oil passage 64 to the drain when the spool 61a is at the P and N positions. For this reason, neither the forward clutch 25 nor the reverse brake 27 is engaged. When the spool 61a is in the D, S, L position, the oil passage 63 is connected to the drain and the line pressure PMOD supplied from the oil passage 31c is supplied to the oil passage 64. Therefore, the reverse brake 27 is released and the forward clutch 25 is engaged. Further, when the spool 61a is in the R position, the oil passage 64 is connected to the drain and the line pressure PMOD supplied from the oil passage 31c is supplied to the oil passage 63. Therefore, the forward clutch 25 is released, and the reverse brake 27 is engaged / released by the operation of the reverse brake control valve 65 described below.
[0039]
The reverse brake control valve 65 has a linear solenoid 65 a, and the pressing force of the linear solenoid 65 a acts on the spool 66. For this reason, the line pressure PMOD supplied through the oil passage 63 is adjusted according to the energizing current of the linear solenoid 65 a to produce the reverse brake control pressure Prv, and this reverse brake control pressure Prv is passed through the oil passage 67. And supplied to the reverse brake 27. As can be seen from the above, the engagement control of the reverse brake 27 can be performed by the reverse brake control valve 65, that is, by controlling the energization current to the linear solenoid 65a.
[0040]
In the control device configured as described above, if the main clutch 5 is engaged and the forward clutch 25 or the reverse brake 27 is engaged, the vehicle can travel and further control the control hydraulic pressure PSV. If the position of the spool 53a of the shift valve 53 is controlled, the hydraulic pressure in each of the cylinders 14 and 19 can be controlled to perform the shift control.
[0041]
【The invention's effect】
As described above, according to the present invention, when the control current supplied to the clutch control valve is lower than the specified current, the pitot pressure is supplied to the hydraulic clutch, and when the control current is higher than the specified current, the line is set according to the control current. Since the pressure is regulated to create the clutch control pressure and this clutch control pressure is supplied to the hydraulic clutch, it is possible to control either the pitot pressure or the clutch control hydraulic pressure by simply controlling the current value flowing to the clutch control valve. The control device configuration can be simplified and the control to supply the hydraulic clutch to the hydraulic clutch and the pressure regulation control of the clutch control hydraulic pressure supplied in this way can be simplified. The manufacturing cost of the control device can be reduced.
[0042]
Further, when this transmission is used for a vehicle, a control hydraulic pressure corresponding to a control current supplied to the clutch control valve is hydraulically controlled at the time of vehicle start, which requires a fine and delicate hydraulic clutch engagement control for smooth start control. It is possible to perform fine control by supplying it to the clutch. On the other hand, at the time of stopping and steady running where not very fine control is required, it is sufficient to perform hydraulic clutch engagement control using pitot pressure. it can. As a result, the control current supplied to the clutch control valve during steady running and when the vehicle is stopped can be lowered (lower than the specified current), and the power consumption of the clutch control valve can be suppressed. It should be noted that when the vehicle is stopped and during steady running, it is preferable that the control current flowing through the clutch control valve is set to zero and the pitot pressure is supplied to the hydraulic clutch, so that the power consumption can be reduced most. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the overall configuration of a belt-type continuously variable transmission having a clutch control device according to the present invention.
FIG. 2 is a skeleton diagram showing a power transmission path configuration in a belt-type continuously variable transmission having a clutch control device according to the present invention.
FIG. 3 is a hydraulic control circuit diagram constituting the clutch control device.
FIG. 4 is a hydraulic control circuit diagram constituting the clutch control device.
FIG. 5 is a hydraulic control circuit diagram showing a portion around a main clutch control valve constituting the clutch control device.
FIG. 6 is a hydraulic control circuit diagram showing a portion around a main clutch control valve constituting the clutch control device.
FIG. 7 is a graph showing the relationship between the energizing current Is of the linear solenoid and the main clutch control pressure PSC in the main clutch control valve.
FIG. 8 is a hydraulic control circuit diagram showing a different example of a main clutch control valve constituting the clutch control device.
FIG. 9 is a graph showing the relationship among the energizing current Is of the linear solenoid valve, the control pressure Pc, and the main clutch control pressure PSC in this main clutch control valve.
[Explanation of symbols]
1 Input shaft
2 Counter shaft
5 Main clutch
10 Metal V-belt mechanism
11 Drive-side movable pulley
15 Metal V belt
16 Driven-side movable pulley
20 Forward / reverse switching mechanism
25 Forward clutch
27 Reverse brake
75 Main clutch control valve

Claims (3)

A hydraulic clutch engaged and actuated by receiving hydraulic pressure for power transmission control in the transmission;
A line pressure source for generating line pressure;
A Pitot pressure supply source for generating Pitot pressure according to the drive rotation speed of the transmission;
A clutch control valve configured to selectively supply the line pressure and the Pitot pressure to the hydraulic clutch,
This clutch control valve is operated in response to a control current,
When the control current is lower than a specified current, the Pitot pressure is supplied to the hydraulic clutch,
When the control current is higher than the specified current, the line pressure is adjusted according to the control current to create a clutch control pressure, and the clutch control pressure is supplied to the hydraulic clutch. A hydraulic clutch control device for a transmission. The transmission is used for a vehicle,
When starting the vehicle, a control current higher than the specified current is supplied to the clutch control valve to supply a clutch control pressure corresponding to the control current to the hydraulic clutch.
2. The system according to claim 1, wherein the pitot pressure is supplied to the hydraulic clutch by causing a control current lower than the specified current to flow through the clutch control valve when the vehicle is stopped and during steady running. The hydraulic clutch control device according to 1. 3. The hydraulic clutch control device according to claim 2, wherein the pitot pressure is supplied to the hydraulic clutch by setting a control current flowing through the clutch control valve to zero when the vehicle is stopped and during steady running.

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