JPS6283548A - Hydraulic controller for v-belt type continuously variable transmission - Google Patents

Abstract

PURPOSE:To reduce the discharge loss of an oil pump and prevent the generation of noise and heat generation of a V-belt by adjusting the line pressure to the necessary min. hydraulic pressure with which the low speed ratio can be maintained, in N or P range. CONSTITUTION:The hydraulic pressure supplied from an oil pump 60 acts to the right edge chamber 51 of a regulator valve 50 and an intermediate port 52, and a spool 53 is shifted leftward against a spring 54 by the hydraulic pressure in the right edge chamber 51. Further, the back pressure chambers 57 and 58 for introducing the hydraulic pressure into the lands 56a and 56b of a plunger 56 installed onto the left side of the spool 53 are connected to a speed change ratio control valve 30 and a manual valve 70. Therefore, in case of N or P range, the signal hydraulic pressure acting into the back pressure chamber 50 of the regulator valve 50 becomes OFF by the operation of the manual valve 70, and the lie pressure can be suppressed to the lower value in comparison with that in the D, L, or R range.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hydraulic control device for a V-belt type continuously variable transmission, and in particular to a hydraulic control device for a V-belt continuously variable transmission.
Or it relates to a pressure regulator for line pressure in the P range.

Conventional technology and its problems Previously, hydraulic chambers were provided on both the driving pulley and the driven boolean around which the belt was wound, and one hydraulic chamber was supplied with line pressure to add the belt tension necessary for torque transmission. The V is always in operation, and the other hydraulic chamber is supplied with line pressure by a gear ratio control valve to achieve continuously variable speed.
For example, a belt type continuously variable transmission is disclosed in Japanese Patent Application Laid-Open No. 59-62762.
This method is disclosed in Japanese Patent Application Laid-open No. 175664/1983.

In the V-belt type continuously variable transmission, the clutch is provided upstream of the drive pulley, so the pulley is stopped in the N or P range. Therefore, if the pulley ratio has not returned to a low speed ratio that allows restart in the N or P range, it is necessary to lower the oil pressure of the driving pulley and increase the oil pressure of the driven pulley to shift to a low speed ratio. However, this requires the oil pressure of the driven pulley to be extremely high, resulting in a large discharge loss of the oil pump (particularly when a resin or rubber belt is used as the V-belt, the belt and Because of the frictional contact with the boot, even if the oil pressure of the driven side boolean is increased while the engine is stopped, the pulley ratio cannot be returned to a low speed ratio.

As a way to solve this problem, for example, a power intermittent clutch is installed between the driven pulley and the output shaft, and in the N or P range, this clutch is disconnected and the pulley is idled by the driving force of the input shaft while shifting to a low speed ratio. There are ways to do this. In this case, there is an advantage that the gear ratio can be quickly shifted to a low speed ratio with a relatively low oil pressure. however,
In conventional hydraulic control, the line pressure is not regulated differently in the N or P range than in other ranges, so
Even after the pulley ratio returns to the low speed ratio, unnecessarily high line pressure is guided to the driven pulley, increasing the oil pump's discharge loss, and causing noise and heat generation due to excessive side pressure on the V-belt. This had the disadvantage of shortening the life of the belt.

Purpose of the Invention The present invention has been made in view of such conventional problems.
Its purpose is to regulate the line pressure to the minimum oil pressure necessary to maintain a low speed ratio in the N or P range, reduce oil pump discharge loss, and prevent V-belt noise and heat generation. An object of the present invention is to provide a hydraulic control device for a transmission.

Structure of the Invention In order to achieve the above object, the present invention provides a thrust adding device that adds belt tension necessary for torque transmission to one of the driving pulley or the driven pulley, and a hydraulic pressure device that changes the gear ratio to the other. In a V-belt continuously variable transmission in which an input shaft is connected to a driving pulley and a driven pulley is connected to an output shaft via a power intermittent clutch, line pressure is supplied to the hydraulic chamber. A gear ratio control pulp that supplies and discharges, a regulator pulp that regulates the line pressure itself, D,
It is equipped with a manual valve that switches between forward and backward travel according to each range such as R, N, P, etc. and that disconnects and connects hydraulic pressure to the power intermittent clutch, and the output hydraulic pressure of the manual valve is guided to the back pressure chamber of the regulator pulp. It is something.

That is, in the N or P range, the output hydraulic pressure of the manual valve is OFF, so the hydraulic pressure in the back pressure chamber of the regulator pulp is also OFF, and the line pressure can be regulated to the minimum floor hydraulic pressure necessary to maintain the low speed ratio.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows an example of a V-belt type continuously variable transmission according to the present invention, in which the power of an engine 1 is transmitted to an input shaft 3 via a fluid coupling 2.
This input shaft 3 is connected to a drive shaft 7 of a V-belt transmission 6 via a reduction gear 4.5.

The V-belt transmission device 6 includes a drive-side pulley 8 provided on a drive shaft 7, a driven-side pulley 12 provided on a driven shaft 11, and a V-belt 14 wound between both pulleys. The drive side boot +J 8 has a fixed sheave 8a and a movable sheave 8b, and a thrust applying device 9 provided behind the movable sheave 8b applies belt tension necessary for torque transmission. As the thrust adding device 9, for example, a torque cam device that generates a thrust according to the input torque of the drive shaft 7, a centrifugal actuator that generates a thrust according to the rotation speed of the drive shaft 70, or a predetermined thrust that generates a predetermined thrust by line pressure. Hydraulic servo equipment, etc. can be used. On the other hand, similarly to the driving pulley 8, the driven pulley 12 also has a fixed sheave 12a and a movable sheave 2b.
A hydraulic chamber 13 is provided behind the movable sheave 12b to operate the movable sheave 12b in the axial direction by hydraulic pressure. The pulley ratio can be freely changed by controlling the oil pressure (control oil pressure P) to this oil pressure chamber 13 by a hydraulic control device which will be described later.

A hollow shaft I5 is rotatably inserted around the outer periphery of the driven shaft II, and the driven shaft 11 and the hollow shaft 15 are connected to each other by a power intermittent clutch 16. The hollow shaft 15 has a forward gear 1.
7 and a reverse gear 18 are rotatably inserted, and either the forward gear 17 or the reverse gear 18 can be connected to the hollow shaft 15 by a forward/reverse switching sleeve 19. The above-mentioned Clara top 16 and forward/reverse switching sleeve 19 are controlled by a hydraulic control device which will be described later.

The reverse idle shaft 20 is arranged parallel to the driven shaft 11, and a reverse idle gear 21 that meshes with the reverse gear 18 and another reverse idle gear 22 are fixed to this shaft 20. A counter shaft 23 is also arranged parallel to the driven shaft 11, and a counter gear 24 and a final reduction gear 25, which simultaneously mesh with the forward gear 17 and the reverse idle gear 22, are fixed to the counter shaft 23. , the final reduction gear 25 meshes with the ring gear 27 of the differential device 26, so that power can be transmitted to the output shaft 28.

FIG. 2 shows a hydraulic control device in the P range, where 30 is a gear ratio control valve, 40 is a solenoid valve, 50 is a regulator valve, 70 is a manual pulp, 80 is a forward/reverse switching valve, and 90 is a clutch control valve.

The gear ratio control valve 30 has a spool 32 biased leftward by a spring 31.
Hydraulic pressure (solenoid pressure Ps) controlled by a solenoid valve 40 is guided to the right end chamber 33 that accommodates the solenoid valve 40 . The solenoid valve 40 is duty-controlled by a control circuit (not shown). Here, duty control is O
A pulse signal with a predetermined period including N time and OFF time is given, and the ratio of ON time to the period (called duty ratio) is
This refers to control that generates a solenoid pressure PS that is approximately proportional to the duty ratio by changing the solenoid pressure PS. On both sides of the port 34 that communicates with the hydraulic chamber 13 of the driven pulley 12, there are a port 35 to which line pressure is introduced and a drain port 36.
is formed. The port 34 communicating with the hydraulic chamber 13 communicates with the left end chamber 37 via a communication hole 32a formed inside the spool 32, thereby controlling the control hydraulic pressure P. is controlled by the oil pressure given by the following equation:

In the above formula, A is the diameter of the left land 32b of the spool 32, B is the diameter of the right land 32C, and Sl is the spring 31.
This is the spring force. If the duty ratio of the solenoid valve 40 is determined as described above, the solenoid pressure P is uniquely determined, and once the solenoid pressure Ps is determined, the control oil pressure P is determined by the above formula. is uniquely determined, and furthermore, the control oil pressure P. Once this is determined, the pulley ratio is uniquely determined, so the pulley ratio can be freely controlled by the duty ratio of the solenoid valve 40.

Right end chamber 51 of regulator valve 50 and intermediate port 5
Hydraulic pressure sent from the oil tank 6I via the strainer 62 by the oil pump 60 acts on 2.
Due to the hydraulic pressure in the right end chamber 51, the spool 53 of the regulator valve 50 moves to the left against the spring 54, and when the land 53a of the spool 53 reaches the position shown in the drawing, the ports 52 and 55 communicate, and the oil is transferred to the oil pump. 60 is returned to the suction side. On the left side of the spool 53, there is a plunge medium 5 having two lands 56a and 56b with different diameters.
6 are arranged, and back pressure chambers 57 and 58 are formed to guide hydraulic pressure to these lands 56a and 56b. One back pressure chamber 5
7 is connected to the right end chamber 33 of the gear ratio control valve 30 to which the solenoid pressure Ps is guided, and the other back pressure chamber 58 is connected to the manual valve 70 via the forward/reverse switching valve 80. ON and N in L range.

In the P range, a signal oil pressure Pw of ○FF is derived. Therefore, when the solenoid pressure Ps or the signal oil pressure Pm acts on the back pressure chamber 57, 58, the plunger 56 pushes the spool 53 to the right, and the line pressure PL is calculated as follows: solenoid pressure Ps, signal oil pressure Pm, spring 54. The hydraulic pressure is adjusted to be balanced by the sum of the spring force S2 and the spring force S2.

In the above formula, C is the land 53b at the right end of the spool 53.
, D is the diameter of the land 56a of the plunger 56, and E is the diameter of the land 56b.

The manual pulp 70 operates in conjunction with the shift lever to move P,
It has a spool 71 that is operated in each of R, N, D, and L ranges. Line pressure PL acts on the input side port 72, and the two output side ports 73 and 74 are switched by the two lands 71a and 71b of the spool 71. For example, in the P range, the input side boat 72 is closed by the land 71a as shown in the figure, and in the -10,000N range, the land 72 is closed between the input side boat 72 and the output side ports 73 and 74 as shown by the broken line.
1a and 71b, the output oil pressure P,
Both P2 are turned OFF. Further, in the D, L, and R ranges, either the output oil pressure P or 2P2 is turned ON.

The forward/reverse switching valve 80 is connected to the forward/reverse switching sleeve 19.
a piston 82 connected to the piston 82 via a rod 81; a spool 83 connected to the piston 82;
3 to the left at all times. The right piston chamber 85 is connected to the output port 73 of the manual valve 70, and the left piston chamber 86 and port 87 are connected to the output port 74 of the manual valve 70. Port 8 communicating with right piston chamber 85
8 is connected to the back pressure chamber 58 of the regulator valve 50 and a clutch control valve 90 described below. D, L
, R range, the piston 82 moves leftward or rightward, so the output hydraulic pressure P1 or P2 is turned on, and the hydraulic pressure is guided to the back pressure chamber 58 and the clutch control valve 90.

In the N or P range, the piston 82
The spool 83 is at the left end position by the spring 84, and the port 88 communicates with the output side boat 73 of the manual valve 70 via the right piston chamber 85, but the output hydraulic pressure P of this port 73 is OFF, so The signal hydraulic pressure Pm and the Crafts hydraulic pressure in the back pressure chamber 58 are turned off.

The clutch control valve 90 has a spool 92 biased to the right by a spring 91, and the spool 92 is actuated by a clutch signal oil pressure P guided to a port 93 at the right end, and is connected to a port 88 of the forward/reverse switching valve 80. The port 94 and the port 95 leading to the clutch 16, or the port 95 and the drain port 96, are selectively communicated with each other. The clutch 16 is D.

In the L and R ranges, the signal hydraulic pressure P is ON, so the coupled state is maintained, but during sudden deceleration or forward/forward switching, the signal hydraulic pressure P3 is OFF, so it is cut off. Also N
, P range, the signal oil pressure P is ON, but no oil pressure is introduced to the port 94, so the clutch 16 is disconnected.

The operation of the hydraulic control device having the above configuration is as follows.

+1) When driving in the D, L, R ranges, the signal oil pressure Pm acting on the back pressure chamber 58 of the regulator valve 50 is turned ON, and the solenoid pressure Ps acting on the back pressure chamber 57 changes according to the pulley ratio. , line pressure P, is control oil pressure P. In the high-speed ratio range where P is low, the pressure is regulated low, and the control oil pressure P is low. In the low speed ratio range where the pressure is high, the pressure is regulated to be high. In other words, line pressure P
Since L is controlled to the minimum necessary oil pressure according to the boolean ratio, the discharge loss of the oil pump can be reduced, which helps improve fuel efficiency, and also prevents hunting of the vehicle due to the supply and discharge of line pressure to the gear ratio control valve 30. It can be prevented.

(2) When a sudden deceleration is performed while driving in the D range, the signal oil pressure P3 of the clutch control valve 90 is turned OFF, the clutch 16 is disconnected, and the control oil pressure P0 of the oil pressure chamber 13 is increased. As a result, (1) the belt transmission device 6 is controlled to a low speed ratio side while idling in a no-load state by the driving force of the engine 1, and the pulley ratio is quickly shifted to a low speed ratio that allows restarting the vehicle until the vehicle stops. I can do it.

(3) As the N and P range manual valves 70 operate, the signal hydraulic pressure Pm acting on the back pressure chamber 58 of the regulator valve 50 is turned off, so the line pressure P, R, L and R ranges are reduced accordingly. can be kept low. Therefore, when maintaining the pulley ratio at a low speed ratio, oil pump loss can be reduced, and (1) noise and heat generation of the belt 14 due to excessive side pressure can be reduced, and (2) the life of the belt 14 can be increased. In addition, when performing sudden deceleration (2), even if the pulley ratio does not return to the original speed ratio before the vehicle stops, the clutch 16 is disengaged in the N and P ranges, so the low Even if the line pressure P is -, it is possible to shift to and maintain a low speed ratio while causing the V-held transmission 6 to idle.

In the above embodiment, the output hydraulic pressure of the manual valve 70 is transferred to the regulator valve 5 via the forward/reverse switching valve 80.
0 to the back pressure chamber 58, but instead of this, the output oil pressure P, P2 can be checked as shown by the broken line in FIG.
Even if the groove is directly connected to the back pressure chamber 58 via the ball 100,
You can get similar functionality.

Further, in the regulator valve 50 of the above embodiment, a plunger 56 separate from the spool is arranged on the left side of the spool 53, and this plunger receives the output hydraulic pressure of the manual valve 70. However, the present invention is not limited to this, for example. The plunger may be eliminated and the output hydraulic pressure may be applied to the left end of the spool.

Effects of the Invention As is clear from the above explanation, according to the present invention, the manual 7
Since the output hydraulic pressure of the /Iz half is led to the back pressure chamber of the regulator valve, as the output hydraulic pressure of the manual valve is turned off in the N and P ranges, the line pressure is reduced to the minimum hydraulic pressure required to maintain the low speed ratio. Pressure is regulated. therefore,
In addition to reducing oil pump loss, it also reduces the lateral pressure that causes the belt to break, eliminating problems such as belt noise and heat generation.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram showing the overall configuration of a V-belt type continuously variable transmission according to the present invention, and FIG. 2 is a structural diagram of a hydraulic control device. 3... Input shaft, 6... V-held transmission, 7...
Drive shaft, 8... Drive side pulley, 9... Thrust adding device, 11... Driven shaft, 12... Drive side pulley, 13...
...Hydraulic chamber, I4...V belt, 1G...Power intermittent clutch, 19...Forward/forward switching sleeve, 28...
Output shaft, 3o... Gear ratio control valve, 40... Solenoid valve, 5°... Regulator valve, 58...
...Back pressure chamber, 70...Manual valve, 80-...
- Forward/forward switching valve, 90...Clutch control valve. Applicant Daihatsu Motor Co., Ltd. Agent Patent Attorney Hidetaka Tsutsui Figure 1

Claims (1)

[Claims] (1) A thrust adding device is installed on either the driving pulley or the driven pulley to add the belt tension necessary for torque transmission,
A V-belt continuously variable transmission, which has a hydraulic chamber on the other side that makes the gear ratio variable, the input shaft is connected to the driving pulley, and the driven pulley is connected to the output shaft via a power intermittent clutch. , a gear ratio control valve that supplies and discharges line pressure to the hydraulic chamber, a regulator valve that regulates the line pressure itself, and a switch between forward and backward movement and the power intermittent operation according to each range such as D, R, N, and P. 1. A hydraulic control device for a V-belt continuously variable transmission, comprising a manual valve that connects and disconnects hydraulic pressure to a clutch, and the output hydraulic pressure of the manual valve is guided to a back pressure chamber of a regulator valve.