JP2843916B2 - Forward / backward switching device for continuously variable transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forward / reverse switching device for a belt-type continuously variable transmission equipped with a torque converter with a lock-up, and more particularly, to a double pinion type planetary gear and a forward clutch. The present invention relates to a clutch and brake operating pressure control and a clutch and brake structure in a configuration using a reverse brake.

[Conventional technology]

2. Description of the Related Art A drive system using a belt-type continuously variable transmission as a drive system of a vehicle has already been proposed. In this drive system, a forward / reverse switching device for switching between forward, reverse, and neutral is disposed on an input side of the continuously variable transmission. It has already been proposed by the applicant. Here, forward and backward switching is performed by hydraulic pressure, and further, the gear ratio in the case of reverse travel can be set to 1.0 with respect to forward travel.It is composed of a double pinion type planetary gear, and the transmission case and the ring gear are fixed with reverse brakes. There is a system that outputs inverted power to the carrier.

Here, in the above-described method, since the ring gear fixed by the reverse brake at the time of reverse travel receives both the input and output torque reaction forces, the torque of the reverse brake requires twice the torque capacity of the input torque. For this reason, in a reverse brake, it is required to increase the torque capacity depending on the operating pressure and the number of plates. In this case, if the number of plates is increased, the dimension in the axial direction becomes longer by that amount, and if the operating pressure suitable for the reverse brake is also used for the forward clutch, pump loss during forward movement and oil leak from the clutch seal portion increase. Not preferred. For this reason, it is desirable to set the operating pressure of the forward clutch and the reverse brake and the number of plates to appropriate values.

Therefore, conventionally, in the forward / reverse switching device of the continuously variable transmission, there is a prior art in Japanese Patent Application Laid-Open No. 63-297862 regarding the control of the operating pressure of the clutch and the brake. here,
A separate hydraulic control system having a low-pressure sub-oil pump is provided for the clutch and the brake of the torque converter, the lock-up, and the forward / reverse switching device. It is shown that the relief valve is variably controlled so that the operating pressure of the forward clutch is low and the operating pressure of the reverse brake is high.

[Problems to be solved by the invention]

By the way, in the above-mentioned prior art, since the hydraulic control system of the continuously variable transmission includes a completely separate hydraulic control system including an oil pump, the structure is inevitably increased in size.
Further, since the discharge pressure of the low-pressure sub-oil pump is relatively low, the operating pressure of the reverse brake cannot be extremely increased. Therefore, the number of plates of the reverse brake cannot be reduced, and there is a limit to shortening the axial dimension. Further, since the forward clutch is provided between the sun gear and the ring gear, the diameter of the clutch increases, the inertia mass increases, and it is disadvantageous for downsizing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic pressure control system of a continuously variable transmission that optimally generates a working pressure for forward / reverse switching, thereby reducing structural inertia mass. It is an object of the present invention to provide a forward / reverse switching device for a continuously variable transmission that can reduce the size and reduce the size.

[Means for solving the problem]

In order to achieve the above object, a forward / reverse switching device of the present invention includes a forward / reverse switching device in a drive system of a continuously variable transmission, and the forward / backward switching device includes a planetary gear, a forward clutch, and a fixing element for the planetary gear. The reverse brake provided for the continuously variable transmission, the line pressure oil passage of the hydraulic control system of the continuously variable transmission and the working pressure oil passage based on the lubricating pressure at least via a select valve that operates in accordance with a shift operation. To communicate with the reverse brake and the forward clutch.

[Action]

Based on the above configuration, the hydraulic pressure of the hydraulic control system of the continuously variable transmission is supplied to the forward clutch and the reverse brake of the forward / reverse switching device. When the vehicle is moving forward, a low operating pressure is introduced into the forward clutch by the select valve and is engaged. When the vehicle is moving backward, a high line pressure is introduced into the reverse brake, and the torque capacity is sufficiently increased to be engaged.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, an outline of a drive system of a continuously variable transmission with a lock-up torque converter will be described. Reference numeral 1 denotes an engine, and a crankshaft 2 is configured to be sequentially transmitted to a torque converter device 3, a forward / reverse switching device 4, a continuously variable transmission 5, and a differential device 6.

In the torque converter device 3, the crankshaft 2 is connected to the converter cover 11 and the pump impeller 12 a of the torque converter 12 via the drive plate 10. A turbine runner 12b of the torque converter 12 is connected to a turbine shaft 13, and a stator 12c is guided by a one-way clutch 14. A lock-up clutch 15 integrated with the turbine shaft 13 is installed between the converter cover 11 and the engine power to transfer the engine power to the torque converter 12 or the lock-up clutch.
The signal is transmitted to the forward / reverse switching device 4 via 15.

The forward / reverse switching device 4 has a double pinion type planetary gear 16, a turbine shaft 13 is input to a sun gear 16a, and a primary shaft 20 is output from a carrier 16b. A forward clutch 40 is provided between the sun gear 16a and the carrier 16b.
The reverse brake 5 between the ring gear 16c and the case.
When the forward clutch 40 is engaged, the planetary gear 16 is integrated and the turbine shaft 13 and the primary shaft 20 are directly connected. Also, the reverse power is output to the primary shaft 20 by the engagement of the reverse brake 50, and the forward clutch 40
And the release of the reverse brake 50 releases the planetary gear 16.

The continuously variable transmission 5 includes a primary pulley 22 having a hydraulic cylinder 21 on a primary shaft 20 and a variable pulley interval, and a secondary pulley 25 having a hydraulic cylinder 24 on a secondary shaft 23. A drive belt 26 is wound around the pulley 25. Here, the pressure receiving area of the primary cylinder 21 is set larger, and the ratio of the winding diameter of the drive belt 26 with respect to the primary pulley 22 and the secondary pulley 25 is changed by the primary pressure to perform stepless transmission.

In the differential device 6, an output shaft 28 is connected to the secondary shaft 23 via a pair of reduction gears 27, and a drive gear 29 of the output shaft 28 meshes with the final gear 30. A differential gear 31 of the final gear 30 is connected to left and right wheels 33 via an axle 32.

On the other hand, in order to obtain a high hydraulic pressure source for control of the continuously variable transmission 5 and the like, the continuously variable transmission 5 is provided with an oil pump 70, and the oil pump 70 is directly connected to the crankshaft 2 via the pump drive shaft 35. .

The forward / reverse switching device 4 will be described in more detail. First, the planetary gear 16 has a sun gear 16a
The carrier 16b is integrally spline-coupled to the primary shaft 20, and the carrier 16b is provided with first and second pinions 16d and 16e supported by the needle 18 of the pinion shaft 17. On the primary shaft 20 side, a gear drum 19 is rotatably mounted via a thrust bearing 36 and the like.
Meshes with the pinion 16e.

The forward clutch 40 is disposed adjacent to the engine side of the planetary gear 16, and a drum 41 having a diameter slightly larger than the ring gear 16 c is spline-coupled to the turbine shaft 13, and further provided so as to be fitted and supported on a stator shaft 37 of the torque converter 12. Also, a hub 42 having substantially the same diameter as the ring gear 16c is integrally connected to the carrier 16b while also supporting the pinion shaft 17,
As described later, for example, four drive plates 43 and five driven plates 44 alternate between the drum 41 and the hub 42 due to the low operating pressure.
a and the spline 41a of the drum 41.
Inside the drum 41, a hydraulic chamber 45 and a piston 46 are provided, and an outer peripheral portion of the piston 46 is in contact with the driven plate 44 side via a dish plate 47, and a return spring 49 from a retainer 48 is attached to the piston 46. Be inspired. Thus, the operating pressure of the hydraulic chamber 45 causes the drive plate 43 and the driven plate 44 to move through the piston 46 and the dish plate 47.
Are pressed against and engaged with each other.

The reverse brake 50 is disposed adjacent to the planetary gear 16 on the side opposite to the engine. A spline 19a on the outer circumference of the gear drum 19 and a spline 7a on the inner circumference of the case 7 overlap with the forward clutch 40. Since the operating pressure in this case is high as described later, for example, two drive plates 51 and three driven plates 52 are alternately fitted to the splines 19a and 7a. The boss 7b of the case 7 is provided with a hydraulic chamber 53 and a piston 54. The piston 54 comes into contact with the driven plate 52 via a dish plate 55, and a return spring 56 is biased. Thus, the piston 54,
The drive plate 51 and the driven plate 52 are pressed against each other via the dish plate 55 to fix the ring gear 16c.

 In FIG. 3, the hydraulic control system will be described.

First, regarding the continuously variable transmission hydraulic control system, a line pressure oil passage from an oil pump 70 communicating with an oil pan 80 will be described.
81 communicates with the line pressure control valve 100 to generate a high line pressure, and this line pressure is
24 are always supplied. The line pressure is guided to the shift speed control valve 110 by an oil passage 83, and is supplied to and discharged from the primary cylinder 21 by an oil passage 84 to generate a primary pressure.

The oil pressure in the drain-side oil passage 85 of the line pressure control valve 100 is relatively high, for example, 4 to 6 kg / cm ² , so that not only the lubrication but also the torque converter 12, the lock-up clutch 15, the forward / reverse switching, and the control original pressure. It is also possible to use it for applications. Therefore, an oil passage 86 branched from the oil passage 85 communicates with the belt lubrication nozzle 87 via a check valve 88 to supply oil to the drive belt 26, and the oil passage 89 contacts the primary movable pulley 22b of the sensor shoe 90 with the oil passage 89. Refueling department.

The oil passage 85 is guided by the reducing valve 120 and constantly generates a constant reducing pressure in the oil passage 91.
Communicates with the line pressure control solenoid valve 109. Oil passage 91
The pressure reducing oil passage 92 branched from the valve communicates with one of the shift speed control valves 110 and a control solenoid valve 119 thereof.

The solenoid valve 109 generates a pulse-shaped control pressure according to the duty signal, which is smoothed by an accumulator 108 and supplied to the line pressure control valve 100 through an oil passage 107. The line pressure control valve 100 has an element according to the gear ratio by the sensor shoe 90 and an element according to the converter state of the oil passage 93, and acts on the gear ratio, engine torque, and torque converter torque amplification when lockup is not performed. The line pressure is controlled by the element.

The solenoid valve 119 also generates a pulse-shaped control pressure according to the duty signal. The reducing pressure acts as the control pressure in opposition to the shift speed control valve 110, and operates at two positions of refueling and draining. Then, the operation state of the two positions is changed by the duty ratio to control the flow rate of oil supply / discharge to the primary cylinder 21, and the speed change control is performed while changing the speed ratio and the change speed. The drain side oil passage 118 of the shift speed control valve 110 has a check valve 117 and communicates with the oil pan 80, and a pre-feeling oil passage 116 communicates between the upstream side of the check valve 117 and the oil passage 85. Thus, the primary cylinder 21 is always filled with oil at the oil discharge position of the shift speed control valve 110.

Next, a hydraulic control system such as a torque converter will be described.

First, the lubricating pressure in the oil passage 85 is regulated by the relief valve 150 to generate a predetermined low operating pressure, and the operating pressure oil passage 140 communicates with the lock-up control valve 170. The lock-up control valve 170 communicates with the apply chamber 15b via the torque converter 12 via the oil passage 141, and communicates with the release chamber 15a of the lock-up clutch 15 via the oil passage 142. A relief valve 143 for preventing an increase in converter internal pressure is provided. The drain oil passage 144 of the lock-up control valve 170 has a check valve 145 for preventing backflow, an oil cooler 1
It communicates with the oil pan 80 via 46.

The reducing pressure from the reducing valve 120 acts on the lock-up control valve 170 via the oil passage 95, and is guided to the oil passage 93 and the lock-up control solenoid valve 179 via the oil passage 94. When the solenoid valve 179 is turned on / off, the lock-up control valve 170 is turned on the oil passages 140 and 141.
Alternatively, the communication is switched to the communication of 142, and the lock-up control pressure is taken out to the oil passage 93.

The line pressure oil passage 96 branched from the oil passage 81 and the working pressure oil passage 97 branched from the oil passage 140 further communicate with a safety lock valve 180, and oil passages 98 and 99 from the safety lock valve 180 are connected to the select valve 190. Communicate with The select valve 190 switches the oil passage according to a shift operation of parking (P), reverse (R), neutral (N), and drive (D).
The select valve 190 communicates with the forward clutch 40 and the reverse brake 50 of the forward / reverse switching device 30 via oil passages 148 and 149, and selectively engages. The safety lock valve 180 has a solenoid valve 189 to which the reducing pressure of the oil passage 95 is guided, and forcibly drains the forward clutch 40 or the reverse brake 50 by turning on / off the solenoid valve 189 to transmit power. Is to be shut off.

The oil passage 9 by the lock-up control solenoid valve 179
The lock-up control pressure of 3 is controlled by the oil passage 147
The relief valve 150 guides the operating pressure of the oil passage 140 to a higher pressure when the torque converter is operating.

In FIG. 4, the forward / reverse switching control system will be described in detail.

The safety lock valve 180 has a spool 182 on a valve body 181 and a solenoid valve 1 on one port 181a of the spool 182.
The control pressure of 89 acts, and the spring 183 is biased in the other direction. When the control pressure is applied when the solenoid valve 189 is turned on, the oil passages 96 and 97 are both connected to the oil passages 98 and 99, and when the solenoid valve 189 is turned off, the drain port 18 and the oil passages 98 and 99 are connected together.
Communicate with 1b.

The select valve 190 has a spool 192 that moves by a shift operation on a valve body 191. And in D range, oil passage 9
9 is connected to an oil passage 149 of the forward clutch 40, and an oil passage 148 of the reverse brake 50 is connected to a drain port 191a.
In the R range, the oil passage 9 is moved by moving the spool 192 to the left.
8 and 148, the oil passage 149 communicates with the drain port 191b, and in the N and P ranges, the oil passages 148 and 149 communicate with the drain ports 191a and 191b.

Thus, in the forward D range, 4 to 6 kg / cm ^{2 of the} oil passage 97
In the reverse R range, a high line pressure of 30 to 40 kg / cm ^{2 in} the oil passage 96 is guided to the reverse brake 50 in the reverse R range.

The operation of the thus-configured continuously variable transmission with lock-up torque converter and the operation of the hydraulic control device will be described.

First, when the engine 1 is started, the oil pump 70 is driven to generate a hydraulic pressure, and a high line pressure regulated by the line pressure control valve 100 is generated in the oil passage 81, and is always supplied to the secondary cylinder 24. Then, the continuously variable transmission 5 is initially set to the low speed stage with the maximum speed ratio.

On the other hand, a constant reducing pressure generated from the reducing valve 120 by using the lubricating pressure of the oil passage 85 on the drain side of the line pressure control valve 100 as a base pressure is used to control the line pressure, the speed change, the lock-up and the safety lock. Valve 109,11
Guided to 9,179,189, it is controllable. The operating pressure of the oil passage 140 whose lubrication pressure has been adjusted by the relief valve 150 is guided to the lock-up control valve 170, and the lock-up control valve 170 connects the oil passages 140 and 142 by the solenoid valve 179 at the time of starting. Therefore, the operating pressure flows into the torque converter 12 via the lock-up release side, and further circulates back to the oil pan 80 via the oil passages 141 and 144. Thereby, the lock-up clutch 15 is released, and the torque converter 12 is in the operating state. Further safety lock valve
180 is the oil passage 96 and 9 by the solenoid valve 189 when normal
8, by communicating the oil passages 97 and 99, the line pressure of the oil passage 96 and the operating pressure of the oil passage 97 are guided to the select valve 190.

Here, when the engine is started in the P or N range, the forward clutch 40 and the reverse brake 50 of the forward / reverse switching device 4 are both drained and released by the select valve 190, so that the planetary gear 16 becomes free, Power transmission after the continuously variable transmission 5 is interrupted.

Therefore, when shifting to the D range at the time of starting, a low operating pressure is supplied to the hydraulic chamber 45 of the forward clutch 40 of the forward / reverse switching device 4 via the oil passages 99 and 149 by the select valve 190, and the drive plate 43 and the driven plate are driven by the piston 46. The sun gear 16a and the carrier 16b are connected to each other by pressing them against each other. For this reason, the planetary gears 16 are integrated, and the turbine shaft 13 and the planetary gear shaft 20 are directly connected to each other, so that the planetary gears 16 are moved forward. Therefore, the power of the engine 1 transmitted to the torque converter 12 is input to the continuously variable transmission 5, and the primary pulley
22, the transmission power having the maximum transmission ratio is output to the secondary shaft 23 by the secondary pulley 25 and the drive belt 26, and transmitted to the wheels 33 via the differential device 6 to travel.

When the torque converter 12 is operating at the time of starting, the lockup control pressure is input to the line pressure control valve 100 via the oil passage 93 by the lockup control solenoid valve 179, and the line pressure is controlled to increase. . Therefore, a large torque when the torque converter 12 performs the torque amplifying operation according to the speed ratio is transmitted without causing belt slip due to an increase in the pulley pressing force due to the line pressure of the continuously variable transmission 5.

Then, after starting, for example, at the start of shifting, the torque converter
When the lock-up control solenoid valve 179 is turned off at the time when the valve 12 substantially enters the coupling region, the lock-up control valve 170 switches so that the oil passages 140 and 141 communicate with each other.
As a result, the release chamber 15a of the lock-up clutch 15 is drained, and the operating pressure is applied to the apply chamber 15b.
Thus, the torque converter 12 is locked up, and the torque converter 12 is locked. Therefore, thereafter, the engine power is transmitted efficiently via the lock-up clutch 15.

On the other hand, at this time, since the lock-up control pressure of the oil passage 93 becomes zero, the line pressure is controlled by the line pressure control valve 100 except for the torque amplification, thereby avoiding an excessive pulley pressing force. Further, the duty of the shift speed control valve 110 is controlled by the solenoid valve 119, and the primary pressure is generated by supplying and discharging oil to and from the primary cylinder 21, so that the drive belt 26 shifts to the primary pulley side and shift control is performed at a predetermined shift speed. It is done.

When shifting to the R range, a high line pressure is supplied to the hydraulic chamber 53 of the reverse brake 50 of the forward / reverse switching device 4 via the oil passages 98 and 148 by the select valve 190, and the piston 54
Thus, the drive plate 51 and the driven plate 52 are pressed against each other to fix the ring gear 16c to the case. For this reason, the reverse power of the gear ratio of 1.0 is output to the primary shaft 20 via the carrier 16b of the planetary gear 16, and the primary shaft 20 enters the reverse state. Therefore, the continuously variable transmission 5 and the subsequent units reversely rotate and travel backward.

In reverse, the reverse brake 50 is engaged by using a high line pressure for continuously variable transmission.
Even if the number of 51 is small, the torque capacity is large. Therefore, the reverse brake 50 sufficiently receives both the input and output torque reaction forces, and smoothly outputs the reverse rotation power. Further, since the hydraulic chamber 53 on the fixed side of the reverse brake 50 does not rotate and is a fixed element, inconvenience such as a decrease in line pressure due to oil leak does not occur.

Although the embodiments of the present invention have been described above, the present invention can be similarly applied to clutches other than the torque converter with lock-up. The planetary gear of the forward / reverse switching device can be similarly applied to other configurations.

[Effects of the Invention] As described above, according to the present invention, in the forward / reverse switching device of the continuously variable transmission, the forward clutch is engaged with the operating pressure based on the low lubricating pressure of the continuously variable transmission hydraulic control system. Therefore, oil leakage at the time of forward high speed is small, and pump loss and the like can be reduced.

Furthermore, by engaging the reverse brake using the line pressure, the torque capacity can be sufficiently increased, and the axial dimension can be reduced by reducing the number of plates.

Further, the forward clutch is provided between the sun gear and the carrier inside the reverse brake, so that the size of the forward clutch is reduced, and the durability of the pinion of the carrier is improved by supporting both ends.

Furthermore, the hydraulic system is simplified by using the lubricating pressure of the continuously variable hydraulic control system for the torque converter, lock-up clutch, forward / reverse switching, and the like.

In addition, since the reverse brake is installed in the case material, there is no fear of leakage of high pressure line pressure, and it is easy to route hydraulic pressure.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing an embodiment of a forward / reverse switching device for a continuously variable transmission according to the present invention, FIG. 2 is an enlarged sectional view of the essential parts, FIG. 3 is a circuit diagram of a hydraulic control system, FIG. FIG. 3 is a circuit diagram of forward / reverse switching control. 4. Forward / reverse switching device, 5 ... continuously variable transmission, 16 ... planetary gear, 40 ... forward clutch, 50 ... reverse brake, 96 ... line pressure oil passage, 97 ... working pressure oil passage,
98,99,148,149 …… oil passage, 180 …… safety lock valve, 19
0 …… Select valve

Claims (1)

(57) [Claims] A forward / reverse switching device is provided in a drive system of a continuously variable transmission, wherein the forward / reverse switching device comprises a planetary gear, a forward clutch for forward movement, and a reverse brake for reverse movement provided on a fixed element of the planetary gear. The line pressure oil passage of the hydraulic control system of the continuously variable transmission and the working pressure oil passage based on the lubrication pressure are connected to the reverse brake and the forward clutch via a select valve that operates at least according to a shift operation. Forward / backward switching device for a continuously variable transmission.