JPS6148658A - Speed-change controller for continuously variable transmission - Google Patents

Abstract

PURPOSE:To improve the acceleration feeling between a speed-change starting point and a completion point by increasing the load of the adjusting spring installed between the adjusting plungers which are shifted by a line pressure, according to the speed change ratio. CONSTITUTION:When a car starts traveling in D range, a Pitot pressure acts onto a spool 72 in a speed change ratio control valve 70, and operation in shift- up direction is performed, and while, the ports 71b and 71d are allowed to communicate by the loads of a spring 74 corresponding to the opening degree of an accelerator and a spring 77 set between the first and the second adjusting plungers 75 and 110 adjusted by a line pressure, and the operation in shift-down direction is performed. After the start of speed change, the first and the second adjusting plungers 75 and 110 project from the spool 72 and an operating plunger 73 with the reduction of the line pressure, and the adjusting spring 77 is compressed, and the large rise of the pitot pressure is made necessary.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a speed change control device for a dual-purpose belt type continuously variable transmission, and particularly to speed change characteristics in an acceleration region in a D (drive) range.

[Prior art]

Regarding the speed change control of this type of continuously variable transmission, a basic hydraulic speed change control system has been proposed in, for example, Japanese Patent Application Laid-open No. 55-65755. A pressure regulating valve adjusts the line pressure based on the 1ζ pitot pressure according to the actual gear ratio and engine rotation, and the main boolean adjusts the line pressure in an equilibrium relationship between the spring load depending on the accelerator opening and the vibration pressure. It has a gear ratio control valve that performs gear change control by supplying and discharging oil to the opposite side. Therefore, it is the gear ratio control valve that essentially changes the gear ratio to control the gear change, and as mentioned above, this It is configured to operate in an equilibrium relationship between the pitot pressure and the "spring load corresponding to the opening degree. Therefore, the components of the engine rotation act as feedback at the accelerator opening degree, and for example, the driving load When the vehicle speed increases and the engine speed increases due to a decrease in gear ratio, the gear ratio shifts to the upshift side with a smaller gear ratio and balances out.
On the other hand, when the engine speed decreases due to an increase in running resistance, the gear ratio shifts to the downshift [- side with a large gear ratio, and equilibrium is established. From this, each gear ratio during continuously variable transmission is determined by the relationship between the accelerator opening degree and the load, and the gear ratio in this case is controlled by the pitot pressure that corresponds to the engine rotation. This controls the engine speed to remain constant. As a result, when applied to actual driving, the engine speed is the same in the high speed gear with a small gear ratio and the low gear gear with a large gear ratio, so the engine speed is too high in the low gear and too low in the high gear. Drivability is Oshi. It cannot be optimal in terms of engine braking characteristics, etc. In addition, due to the structure of the gear ratio control valve, a strong spring that corresponds to the accelerator opening is in a direct equilibrium relationship with the pitot pressure, so the pitot pressure is delayed in response to changes in the accelerator opening before it acts as a feedback. There are problems such as the spool operating and unnecessary shifting, making it difficult to smoothly shift gears. Therefore, in order to deal with the above-mentioned problem,
For example, a prior art technique has been proposed in Japanese Unexamined Patent Publication No. 56-66553. This is because the line pressure regulated by the pressure regulating valve changes based on the gear ratio. An adjustment spring is also biased between the operating plunger and the adjustment plunger, which are pushed in depending on the speed.When upshifting to a high speed gear with a small gear ratio, the adjustment plunger is pushed in due to a drop in line pressure. The spring load of the adjustment spring is increased by increasing the spring load of the adjustment spring, and the pitot pressure that is balanced with the accelerator opening side is adjusted to be high.This causes a shift that increases the engine speed as the gear ratio is shifted to a high speed gear with a small gear ratio. Therefore, in this case, for example, the shift characteristic when accelerating with the accelerator fully open is as shown by the solid line in Fig. 3, where the shift start point A is the curved line with the maximum gear ratio, and the shift end point is the curved shift point A where the gear ratio is the highest. The rate of increase in engine speed between point B and the rate of increase in engine speed is smaller than the rate of increase in vehicle speed.
Lack of acceleration feeling1). In addition, it is possible to set the maximum vehicle speed point B high so that it matches the rotational speed of the engine's maximum horsepower by changing the shape and spring load of the plunger of the gear ratio control valve. As the entire curve shifts to the higher engine speed side, the engine speed at shift start point A becomes too high.
This is unfavorable in terms of fuel efficiency, etc.

[Purpose of the invention]

In view of these circumstances, the present invention increases the engine speed increase ratio between the shift start point and the shift end point in the D range shift characteristics of the continuously variable transmission, and increases the engine speed increase ratio in the direction that matches the vehicle speed increase ratio. It is an object of the present invention to provide a speed change control device for a continuously variable transmission that improves the acceleration feeling by bringing the speed closer to each other. (Configuration 1 of the Invention For this purpose, the configuration of the present invention is such that in the gear ratio control valve, an operation plunger that is displaced according to the accelerator opening is connected to the spool via a spring, and inside the spool is a plunger that is displaced according to the line pressure. Adjust the adjustment plan seat to the right and adjust this WJ.
An adjustment spring is installed between the adjustment plunger and the operation plunger, and as the line pressure decreases when shifting up to a high speed gear, the load of the adjustment spring is increased and acts against the pitot pressure, causing the engine to shift. It is configured to obtain a speed change characteristic that gradually increases the rotation, and focusing on the fact that the rate of increase in the load of the adjustment spring directly affects the rate of increase in engine rotation, the inside of the operating plunger is equipped with a similar structure as on the spool side. Another adjustment plunger displaced by line pressure is provided to double the load on the adjustment spring in relation to the gear ratio.
The gist of this is to increase the rate of increase in engine rotation between the shift start point and the shift end point.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In FIG. 1, an example of a belt type continuously variable transmission to which the present invention is applied will be described. Reference numeral 1 is an electromagnetic powder clutch, 2 is a continuously variable transmission, and continuously variable 3! Broadly speaking, the machine 2 includes a forward/reverse switching section 3, a pulley ratio converting section 4, and a final reduction section 5, all of which are transmitted from the input side. The electromagnetic powder clutch 1 is housed in one side of the clutch housing 6, and the other parts of the clutch housing 6, the main case 1 connected thereto, and the main case 7 connected to the opposite side of the clutch housing 6. side booth 8
The switching unit 3, pulley ratio converting unit 4, and final reduction unit 5 of the continuously variable transmission f3312 are assembled (pulled) inside.
A ring-shaped drive member 12 is integrally connected to the drive plate 11 via a drive plate 11, and a disk-shaped driven member 14 is integrally spline-connected to the transmission input shaft 13 in the rotational direction. A coil 15 is built into the outer peripheral side of the driven member 14, and a two-V shaft 11G with a long circumference is formed between both members 12.14, and this gear/tube 16 has electromagnetic powder inside. It communicates with the powder chamber 17. A power supply brush 19 slides on the slip ring 18 of the hub portion of the driven member 14 equipped with the coil 15, and is further connected to the coil 15 through the inside of the driven member 14 from the slip ring 18 and connected to the coil 15. A current circuit is configured. In this way, when a clutch current is applied to the coil 15, it passes through the gap 16 to the drive and driven members 12, 14.
The electromagnetic particles are coupled in a chain to the magnetic field lines generated between J and J, and the electromagnetic powder is bonded to the top 16, resulting in a bonding force of τ, and due to this bonding force, the driven member 14 slides and is integrally coupled to the drive member 12. It becomes connected. On the other hand, when the clutch current is cut, the coupling force between the drive and driven members 12 and 14 due to the electromagnetic powder disappears, resulting in a clutch disengaged state. If the control of the clutch current in this case is performed in conjunction with the operation of the switching unit 3 of the continuously variable transmission 2, it is possible to move forward from the P (parking) or N (coatral) range, to the O5 (sporty drive) or R of retreat
(When switching to the reverse range, the clutch 1 automatically moves back and forth, eliminating the need for clutch pedal operation.) Next, in the continuously variable transmission 2, the switching section 3 connects the input shaft 13 from the clutch 1 to the input shaft 13. Main shaft 2 arranged coaxially
0. That is, the input shaft 13 is formed with a reverse drive gear 21 that also serves as a forward engaged side, and a gear 1' 722 on the reverse engaged side is rotatably fitted on the main shaft 20. Gears 1721 and 22 are meshed with each other via a counter gear 24 supported by a shaft 23 and an idler gear 172G supported by a shaft 25. Then, a cut 113 is provided between the main shaft 20 and the gears 21 and 22.
! A mechanism 27 is provided. Here, the gears 21, 24, 26, and 22 that are always engaged are the coil 1 of the clutch 1.
The switching mechanism 27 has a sleeve 29 that is spline-fitted to the hub 28 of the main shaft 20. It is configured so that it is meshed and connected to each gear 721.22 via the synchronizing mechanism 30.31.1 As a result, Py is in the neutral position e of the N range when the sleeve 29 of the switching mechanism 27 is connected to the hub 28. Only fit the main shaft 2.
0 is disconnected from the input shaft 13. Next, the sleeve 29
Through the synchronizing mechanism 30, the main shaft 20 is directly connected to the input shaft 13 and becomes the forward state of the D or DS range. When engaged with gear 22 through In the conversion unit 4, a sub-shaft 35 is arranged parallel to the main shaft 20, and a main pulley 36 and a sub-pulley 37 are provided on both shafts 20 and 35, respectively.
, 37, there is an endless drive belt, 34, which is passed over. The pulleys 36 and 37 are each divided into two parts, and one half of the pulleys 36a and 37a is divided into two halves, while the other half of the pulleys 36+) and 371) have a variable pulley interval.
The movable pulley is partially rested (361),
371) is equipped with a hydraulic servo device 38, 39 which also serves as a piston, and furthermore, a spring 40 is applied to the movable half of the auxiliary pulley 3γ (371) in the direction of narrowing the pulley spacing. There is. Also, a Δ oil pump 41, which is an operating source such as a hydraulic control system, is installed next to the main pulley 36. This oil pump 4
Reference numeral 1 designates a high-pressure gear pump, in which a pump drive shaft 42 passes through the main pulley 36, main shaft 20, and input shaft 13 and is directly connected to the crankshaft 10, so that hydraulic pressure is constantly generated during T engine operation. . and. Each hydraulic servo M controls the hydraulic pressure of this oil pump 41.
Supply and drain oil to rJ38.39, and connect main pulley 3G and sub pulley 3.
7 is changed to the opposite relationship.C1 drive belt 3
The pulley ratio in the pulley 36.3'7 of No. 4 is converted steplessly, and the steplessly variable power is output to the subshaft 35. In view of the fact that the minimum pulley ratio on the high-speed stage side of the pulley converter 4 is very small, for example, 0.5, and the rotational speed of the I-pull subshaft 35 is high, the final reduction unit 5 has a ratio of 1 to the subshaft 35. An output shaft 44 is connected via a set of intermediate reduction gears 43 . Then, the final gear V4G meshes with the drive gear 45 of this output shaft 44, and the differential 'a' is output from the final gear A746.
Power is transmitted to the axles 48 and 49 of the left and right drive wheels via the 4m47. In FIG. 2, to explain the hydraulic system for controlling the speed 1FiII, in the main pulley side hydraulic servo device 38, the movable pulley half 36 is connected to the cylinder 38a which is integral with the main shaft 20.
b is fitted into the main pulley servo chamber 3811 into which line pressure is introduced into the cylinder 38a. In addition, the sub-pulley side hydraulic servo device 39 is also integrated with the sub-shaft 35.
Cylinder 39a k: The movable pulley body 37b is fitted into the cylinder 39a, and the cylinder 39a has an auxiliary pulley servo chamber 391) into which line pressure is introduced. The pressure receiving area is too tight. Then, the oil pumped up from the oil sump 50 by the oil pump 41 passes through the oil passage 51 [-Pressure Figl Valve 6
0, and the line pressure oil passage 52 from this pressure regulating valve 60 always maintains line pressure 2Q to the sub-pulley servo chamber 391).
The oil passage 53 for supplying and discharging line pressure is connected between the transmission ratio control valve 70 and the main pulley servo chamber 381), and the 8 valves 60° 70
Drain oil passages 54 and 55 communicate with the oil sump side. Further, a rotation sensor 5G is installed at the cylinder 38a on the main pulley side to take out a control signal pressure of the pitot pressure according to the engine rotation in the shift control after the clutch is engaged, and the pitot pressure from the rotation sensor 56 is 8 valves 60 via oil passage 57
．． 70 asked. Furthermore, in contrast to the O range, which performs shift control over a wide range including low engine speeds, the oil pressure control is limited to the high engine speed range, and when the accelerator is released, the engine brake is applied () to obtain the S range. As a system, a ball-jump valve 58 is provided in the drain oil passage 54 from the pressure j1g regulating valve 60, and an oil passage 59 of the lubrication hydraulic circuit that branches from the upstream side of this valve 58 communicates with the select position detection valve 90. An oil passage 68 that further branches from the oil passage 59 communicates with the actuator ``11'' of the speed ratio control valve 1o. Spool 6
2. The sensor shoe 65 which is biased between the bushing 63 on one side of the spool 62 and the ring 64 and which engages the movable pulley half 3Gb of the main pulley to detect the actual gear ratio is lubricated. It is movably supported by an axis 66 that also serves as an oil path and is connected to a bush 63. In the valve body 61, the pitot pressure of the oil passage 51 is applied to the port 61a at the opposite end of the spool 62 from the spring 64, and the pump oil pressure of the oil passage 51 is applied to the port 61b. Also, boat t-6
1c is the oil passage 51 on the pump side and the oil passage 5 without line pressure taken out.
Drain oil passage 54.54' is connected to port 61d1 on the spring 64 side of port Glc and port 61e provided between bow 1-61a and 6111 to prevent pump oil pressure leakage from affecting pitot pressure. is connected, and the port 6 is connected to the port 7PA of the land 62a of the spool 62.
The pressure is regulated by connecting 1C and 61d. That is, the pitot pressure and pump oil pressure act on the spool 62 in the direction to open the drain port 61d, whereas the load of the spring 64 according to the gear ratio due to the sensor shoe 65 acts in the direction to open the drain port 61d. do. As a result, for example, in a low speed gear with a large gear ratio, the port 61c
k: Generates high line pressure, and controls the line pressure so that it does not decrease by reducing the spring load as the gear ratio shifts to a higher speed gear, thereby maintaining a pulley pressing force that does not cause belt slip. The gear ratio control valve 70 includes a valve body 71. Spool 12. A spring 14 is biased between the spool 12 and one operating plunger 73, and the pitot pressure of the oil passage 57 is applied to the port 71a at the end of the valve body 71 opposite to the spring γ4 of the spool 72. It will be done. Also, the middle port 7
11), an oil passage 52 communicates with the spring side port 71c, a drain oil passage 55 communicates with the opposite side port 71d, and the groove 72a of the spool 12 communicates with the boat 11b and 71
c or 71d to supply and drain line pressure to the main pulley servo chamber 381). A first adjusting plunger 75 protrudes from the inside of the spool 72 toward the spring 74 and is movably inserted therein, and serves as a stop and a collar at the tip of the protruding portion of the plunger 15 , and also serves as a stop and a collar for the retainer 76 . One end of the spring 77 is locked, and a return spring 78 is biased between the plunger 75 and the spool 72. Then, the line pressure boat 11C communicates with the inside of the spool 72 through the small hole 19 of the spool 12, and applies line pressure to the spool 72 and the plunger 75. In other words, the load on the adjustment spring 77 is changed. The operating plunger 1173 is separated from a rod 81 from a cam 80 that acts to lift when the accelerator is released, and is connected via a weak spring 82. It has a stopper 83 to move the same stroke as the plunger 81.The inside of the plunger 73 is connected to the pitot pressure port 71a via an oil passage 86 having a notch 84 and an orifice 85, and a spring that adjusts the load of the spring 82. 87 is biased between the end of the spool 12 and the valve body 71. Further, the adjustment spring 7 is applied from inside the operating plunger 73.
A second adjustment plunger 110 is protruded and movably inserted on the 7 side, and the other end of the adjustment spring 77 is locked to a retainer 111 that also serves as a stopper at the tip of the protrusion of the first WJ adjustment plunger 110. The second adjusting plunger 110 is constructed in exactly the same manner as the first adjusting plunger 75, and a return spring 1 is provided between it and the operating plunger 73.
12 is energized, the port 71e that communicates with the line pressure oil passage 52 passes through the small hole 113 of the operation plunger 73 to the side opposite to the spring 112 inside the operation plunger 73, and the line pressure causes the second Adjustment plunge 1
The load of the adjustment spring 77 is changed depending on the amount of protrusion of -110. The select position detection valve 90 has a drain hole 92 in the valve body 91.
A return spring 94 is applied to the valve body 93, and a cam 95 that rotates in response to a selection operation is in contact with the valve body 93. Here, in the cam 95, the N and R range positions are convex portions 95a, and the P and DS range positions at both ends are concave portions 95t). 92 is closed to generate operating oil pressure. Further, an A refit 9G is provided on the upstream side of the branch part of the oil passage 68 in the oil passage 59, and
The actuator 100 has a piston 1 in a cylinder 101.
02 is inserted, a return spring 103 is urged on one side of the piston 102, and the operating hydraulic pressure of the oil passage 68 is guided to the other piston chamber 104. Also, the hook 105 at the tip of the piston 102 can engage with the pin 106 of the rod 81 of the speed ratio control valve 70, so that the piston 102 forces the rod 81 when there is no operating oil pressure in the P, Ds plunge. Push the stroke to a specified level and control the gear shift range at high engine speeds. As a result, when the accelerator is released in the DS range, the shift is lowered and engine braking becomes effective. The operation of the shift control device configured as described above will be explained using the shift characteristics shown in FIGS. 1, 2, and 3. First, before the vehicle starts running, the pressure regulating valve 60 is activated in the hydraulic system.
The line pressure regulated in is introduced into the sub-pulley servo chamber 391) through the oil passage 52, while no pitot pressure is generated in the gear ratio control valve 70. Move to main pulley servo chamber 381
1 is draining. Therefore, in the pulley ratio conversion section 4 of the continuously variable transmission 2, the drive belt 34 is fully shifted to the side of the sub pulley 37, and the gear ratio is at the maximum, which is the lowest gear. Next, when the D range is selected when the vehicle starts running,
The input shaft 13 and the main shaft 20 are directly connected in the switching part 3, and when the accelerator is depressed, the electromagnetic powder clutch 1 is engaged by supplying clutch current based on the increase in engine rotation, and this causes the engine power to be transferred to the main pulley. Enter into 3G. And main pulley 36. The driving belt 34 and the auxiliary pulley 37 output the transmission power with the maximum gear ratio to the auxiliary shaft 35, and this is transmitted to the wheels via the final reduction unit 5, so that the vehicle starts running. At this time, in the oil If system, the pitot pressure of the engine rotation corresponding to the depression state of the accelerator is generated from the rotation sensor 56 and acts on the 6 valves 60.70, and the pressure regulating valve 6
At 0, the line pressure is set to be the highest according to the gear ratio, and thereafter, as the gear ratio is shifted up to a higher speed gear, the line pressure is regulated to decrease gradually. On the other hand, in the gear ratio control valve 70, pitot pressure acts on the spool 72 in the direction of upshifting by introducing line pressure into the main pulley servo chamber 381) through communication between the boats 71b and 71c. Adjust the spring 74 and line pressure accordingly! The load of the spring 77 between the first and second adjustment plungers 75 and 110 acts in the direction of draining the main pulley servo chamber 381) and downshifting due to the communication between the ports 1 to 71b and 716, and the gear is shifted in a balanced relationship between the two. You will be able to control the speed change while determining the ratio. Next, after the start of the gear shift, as the line `` is lowered, the gear ratio control valve 70 adjusts the first and second adjusting plunges r75,
110 is the spool 72. Since they both protrude from the operating plunger 73, the adjustment spring 77 begins to be compressed from both sides, and its load increases by f1 compared to when it is compressed from one side. Therefore, when shifting up, it is necessary to increase the bit rate according to the increase in the spring 77, and this results in the shift characteristics when the accelerator is fully open (as shown by the broken line in Fig. 3, as the gears shift up) The upper limit ratio of the engine rotation is increased.Then, at the shift end point B' at the maximum vehicle speed, the engine rotation reaches a higher value than in the conventional case where the rotation speed coincides with the engine's maximum horsepower. In addition, in the gear ratio control valve 70, the pressure also acts on the operating plunger 73, canceling out the force that the detection plunger V73 receives due to the pitot pressure, so that the pushing force of the rod 81 is very small. Furthermore, when the amount of accelerator depression changes, first only the rod 81 is pushed in, and then as the pressure increases, the operating plunger 1P73 moves by the same stroke. The spring load is gradually increased, and in this way, the spool 72 determines the gear ratio while maintaining balance in approximately synchronization with the increase in pitot pressure. and the return spring 7 of the second adjustment plunger v75, 110
By arbitrarily setting the loads 8 and 112, the load characteristics of the adjustment spring 77 change, and it is possible to freely determine the slope and changing state of the speed change characteristics. Effects of the Invention As is clear from the above description, according to the present invention, in the shift control of a continuously variable transmission, for example, the speed change characteristics when the accelerator is fully opened can be improved by increasing the engine speed. Since the ratio increases and approaches the vehicle speed increase ratio, the acceleration feeling improves. In addition, the engine speed at the shift start point can be lowered, which improves fuel efficiency, while the engine speed at the shift end point can be increased to a point where the engine's maximum horsepower can be used, improving engine performance. This allows for maximum gear shifting. Since the same adjustment plan seat is added to the operation plunger as on the spool side, the structure is simple and responsiveness is good.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a continuously variable transmission to which the present invention is applied, Fig. 2 is a circuit diagram of an embodiment of the gearing according to the present invention, and Fig. 3 is a transmission characteristic diagram. 2...Continuously variable transmission, 60...Pressure regulating valve, 70...
・Speed ratio control valve, 71...valve body, 71'c, 71e
...Line pressure port 1~. 12...Spool, 73.
...Operation plunger, 74...Spring, 75...
・First adjustment plunger, 76... Rihanna, 71...
・Adjustment spring, 110... second adjustment plunger,
79.113...Small hole, 111...S' taker.

Claims (1)

[Claims] The hydraulic system of the continuously variable transmission has a pressure regulating valve that regulates line pressure, and a gear ratio control valve that supplies or discharges the line pressure to the main pulley servo chamber to control gear changes, and the gear ratio control valve is connected to the accelerator. An operation plunger that is displaced according to the opening degree is connected to the spool via a spring, and inside the spool and the operation plunger are first and second adjustment plungers that are displaced according to the line pressure. A speed change control device for a continuously variable transmission, characterized in that an adjustment spring is interposed between the two.