JPH0674840B2 - Shift control device for continuously variable transmission - Google Patents

Description

The present invention relates to a shift control device for a continuously variable transmission.

(B) Conventional Technology As a conventional shift control device for a continuously variable transmission, there is, for example, one disclosed in Japanese Patent Laid-Open No. 58-170958. The shift control device of the continuously variable transmission is configured to start discharging the hydraulic pressure on the drive pulley side at the same time when the brake is depressed to start shifting to the higher gear ratio side. In addition, JP-A-58
Japanese Patent Laid-Open No. 170959 discloses a shift control device that starts shifting to a higher gear ratio at the same time when the throttle is fully closed. These speed change control devices foresee the engine braking effect by predicting the need for engine braking from a specific operating condition (that is, using the brake or fully closing the throttle) and immediately starting the speed change to the higher gear ratio side. Is what you are trying to get. This makes it possible to obtain the engine braking effect relatively quickly even in the case of a continuously variable transmission having a slow speed change.

(C) Problems to be Solved by the Invention However, the above-described shift control device for a continuously variable transmission includes:
When the brakes are used or when the throttle is fully closed, shifting to the higher gear ratio side is always started.Therefore, shifting is performed more frequently than the driver actually needs, and the engine brake operates, so the driving feeling is improved. There is a problem that it is not preferable. For example, if the amount of depression of the accelerator pedal is reduced by following the running condition of the vehicle ahead, a shift will be performed and engine braking more than intended will be applied.
Smooth driving will be impaired.

On the other hand, in Japanese Patent Application No. 60-44580 filed by the applicant of the present invention, there is provided a shift control device for a continuously variable transmission that shifts gears to a higher gear ratio side only when the throttle is rapidly closed. Have been described. This makes it possible to prevent the engine brake from acting more than necessary. However, in the case of this speed change control device for a continuously variable transmission, axially long taper portions are provided on both sides of the land of the spool that controls opening and closing of the port connected to the drive pulley, and the position where the spool is located. Even if it is, the throttle effect is generated for the oil flow through this port, so even if the shift motor is controlled to shift to the higher gear ratio side when a sudden shift is required, it is discharged from the drive pulley. The oil that is subjected to the throttle effect at the port cannot move the movable portion of the drive pulley at a speed higher than a predetermined speed. Therefore, the response of the shift to the higher gear ratio side is poor, and for example, when the wheels are locked by applying a sudden brake, the output shaft does not rotate and the detected vehicle speed becomes 0, and the gear ratio is high. If you step on the accelerator pedal after some time has elapsed after the gear shift was started, the pulley is still shifting to the higher gear ratio side and oil is being discharged from the drive pulley. Since it is in the middle, the frictional force does not sufficiently act on the V-belt, so that the V-belt slips, power cannot be transmitted, and the V-belt wears. The present invention aims to solve such problems.

(D) Means for Solving the Problems The present invention eliminates the throttling effect of the shift control valve on the oil discharged from the drive pulley in the state in which a rapid shift to the higher gear ratio side is required. Solve the problem. That is, the shift control device according to the present invention includes a drive pulley and a driven pulley, each of which includes a fixed cone plate and a movable cone plate, a V belt wound between the pulleys, a shift motor, and a shaft according to the rotation of the shift motor. A rod that moves in a direction, a shift control valve that can control the hydraulic pressure that acts on the movable cone plates of both pulleys, and a rod that feeds back the movement of the movable cone plate detected by the gear ratio detection member to the shift control valve, It is applied to a continuously variable transmission having a link connecting a shift control valve and a gear ratio detection member, and a port of the shift control valve connected to an oil passage communicating with a drive pulley and an open / closed state of this port. When the gear ratio detection member is at the highest gear ratio side and the rod that is moved by the gear shift motor is at the highest gear ratio side, the spool land that controls the It is configured in a relationship as the port is fully open.

(E) Action When the gearshift motor is rotated when a sudden gearshift to a higher gearshift ratio is commanded while the vehicle is running with the gear ratio relatively small, the spool of the gear shift control valve moves via the link, and the drive pulley moves. The hydraulic pressure acting on the cone begins to be discharged. In this state, the port of the shift control valve connected to the oil passage communicating with the drive pulley is completely opened, and the hydraulic pressure of the drive pulley is rapidly discharged. As a result, the movable conical plate of the drive pulley moves, the gear ratio detecting member accordingly moves to the higher gear ratio side, and the spool of the gear shift control valve also moves, but the gear ratio becomes the largest. However, the completely opened state of the port is maintained. Therefore, the hydraulic pressure of the drive pulley is always discharged rapidly without any throttling effect during the shift to the higher gear ratio side, and a quick shift is performed. For example, even if the driver suddenly applies the brakes and operates the accelerator pedal after a relatively short time,
When the accelerator pedal is depressed, the shift to the higher gear ratio side has been completed, and the V-belt is in a state in which frictional force can be applied. Therefore, the V-belt does not slip.

(F) Embodiment FIG. 2 shows a power transmission mechanism of a continuously variable transmission to which the present invention is applied. This continuously variable transmission includes a fluid coupling 12, a forward / reverse switching mechanism 15, a V-belt type continuously variable transmission mechanism 29, and a differential device.
56 and the like, the rotation of the output shaft 10a of the engine 10 can be transmitted to the output shafts 66 and 68 at a predetermined gear ratio and rotation direction. This continuously variable transmission has a fluid coupling.
12 (having lock-up oil chamber 12a, pump impeller 12b, turbine runner 12c, etc.), rotating shaft 13, drive shaft 1
4, forward / reverse switching mechanism 15, drive pulley 16 (fixed cone plate 1
8, drive pulley cylinder chamber 20 (composed of chamber 20a, chamber 20b, movable conical plate 22, etc.), planetary gear mechanism 17 (Sun gear 1
9, consisting of pinion gear 21, pinion gear 23, pinion carrier 25, internal gear 27, etc.), V-belt 24,
Driven pulley 26 (fixed cone plate 30, driven pulley cylinder chamber
32, movable cone plate 34, etc.), driven shaft 28, thrust bearing 31, inner race 31a, outer race 31
b, ball 31c, forward clutch 40, drive gear 46, idler gear 48, reverse brake 50, idler shaft 52, pinion gear 54, final gear 44, pinion gear 58, pinion gear 60, side gear 62, side gear 64, output shaft Although it is composed of an output shaft 66, an output shaft 68, etc., detailed description of these components will be omitted. Regarding the configuration of the part of which description is omitted, Japanese Patent Application No. 59-226706 related to the applicant's application
No.

FIG. 1 shows a hydraulic control device for a continuously variable transmission. This hydraulic control device includes an oil pump 101, a line pressure regulating valve 102, a manual valve 104, a shift control valve 106, an adjusting pressure switching valve 108, a shift motor (step motor) 110, a shift operating mechanism 112, a throttle valve 114, a constant pressure. It has a pressure regulating valve 116, a solenoid valve 118, a coupling pressure regulating valve 120, a lock-up control valve 122, etc., which are connected to each other as shown in the drawing, and also have a forward clutch 40, a reverse brake 50, Fluid coupling 12, lock-up oil chamber 12a, drive pulley cylinder chamber
The 20 and the driven pulley cylinder chamber 32 are also connected as shown. Detailed descriptions of these valves and the like other than the gear shift control valve 106, the gear shift operation mechanism 112, etc., which are directly related to the present invention, are omitted. The part of which the description is omitted is described in the aforementioned Japanese Patent Application No. 59-226706. Each reference numeral in FIG. 1 indicates the following member. Pinion gear 110a, tank 130, strainer 131, oil passage 132, relief valve 133, valve hole 134, ports 134a-e, spool 136, land 136a-
b, oil passage 138, one-way orifice 139, oil passage 140, oil passage 14
2, one-way orifice 143, valve hole 146, ports 146a-g,
Spool 148, lands 148a-e, sleeve 150, spring 152, spring 154, gear ratio detection member 158, oil passage 164,
Oil passage 165, orifice 166, orifice 170, valve hole 172, ports 172a-e, spool 174, lands 174a-e, spring 175, oil passage 176, orifice 177, link 178, oil passage 17
9, pin 181, rod 182, land 182a-b, rack 182
c, pin 183, pin 185, valve hole 186, ports 186a-d, oil passage
188, oil passage 189, oil passage 190, valve hole 192, ports 192a-g, spool 194, lands 194a-e, negative pressure diaphragm 198, orifice 199, orifice 202, orifice 203, valve hole 20
4, ports 204a-e, spool 206, lands 206a-b, spring 208, oil passage 209, filter 211, orifice 21
6, port 222, solenoid 224, plunger 224a, spring 225, valve hole 230, ports 230a-e, spool 232,
Land 232a-b, spring 234, oil passage 235, orifice
236, valve hole 240, ports 240a-h, spool 242, land 2
42a to e, oil passage 243, oil passage 245, orifice 246, orifice 247, orifice 248, orifice 249, choke type throttle valve 250, relief valve 251, choke type throttle valve 252,
Pressure holding valve 253, oil passage 254, cooler 256, cooler pressure holding valve 25
8, orifice 259, changeover detection switch 278.

The shift control valve 106 includes a valve hole 172 having five ports 172a, 172b, 172c, 172d and 172e, and a spool 174 having three lands 174a, 174b and 174c corresponding to the valve hole 172.
It consists of a spring 175 that pushes the spool 174 to the left in the figure. 172b communicates with the drive pulley cylinder chamber 20 via an oil passage 176, and ports 172a and 172e are drain ports. An orifice 177 is provided at the outlet of the port 172a. The port 172d communicates with the driven pulley cylinder chamber 32 via the oil passage 179. The line pressure is supplied to the port 172c by communicating with the oil passage 132 which is a line pressure circuit. The left end of the spool 174 is rotatably connected by a pin 181 to a substantially central portion of a link 178 of the gear shift operation mechanism 112 described later. The land 174b has tapered portions 17 on both sides in the axial direction.
4b 'and 174b ". Line pressure supplied to port 172c flows into port 172b, part of which is port
Since it is discharged to 172a, the pressure of the port 172b becomes a pressure determined by the ratio of the inflowing oil and the discharging oil.
Therefore, as the spool 174 moves leftward, the clearance on the line pressure side of the port 172b increases and the clearance on the discharge side decreases, so that the pressure of the port 172b gradually increases. The tapered portion 174b 'has a relatively short axial length. On the other hand, port 172d is usually port 172c
Line pressure is being supplied. The hydraulic pressure of the port 172b is supplied to the drive pulley cylinder chamber 20 via the oil passage 176, and the hydraulic pressure of the port 172d is supplied to the driven pulley cylinder chamber 32 via the oil passage 179. Therefore, when the spool 174 moves to the left, the pressure in the drive pulley cylinder chamber 20 increases and the width of the V-shaped groove of the drive pulley 16 decreases, while the width of the V-shaped pulley groove of the driven pulley 26 decreases. growing. That is, since the V-belt contact radius of the drive pulley 16 increases and the V-belt contact radius of the driven pulley 26 decreases, the gear ratio decreases. On the contrary, when the spool 174 is moved to the right, the action completely opposite to the above causes
The gear ratio becomes large.

The link 178 of the speed change operation mechanism 112 is connected to the spool 174 of the speed change control valve 106 by a pin 181 at approximately the center thereof, and one end of the link 178 is connected to a speed ratio detection member 158 and a pin 183. The other end is connected to the rod 182 by a pin 185. Rod 182 is rack 18
The rack 182c is engaged with the pinion gear 110a of the transmission motor 110. In such a gear shift operation mechanism 112, when the rod 182 is moved to the right in the figure by rotating the pinion gear 110a of the gear shift motor 110 controlled by a gear shift control device (not shown), the link 178 is pinned. A spool of the speed change control valve 106, which rotates clockwise about 183 and is connected to the link 178.
Move 174 to the right. As a result, the movable cone plate 22 of the drive pulley 16 moves to the left in FIG. 1 to increase the V-shaped pulley groove spacing of the drive pulley 16, and at the same time, the V-shaped pulley of the driven pulley 26 accordingly. The groove spacing becomes smaller and the gear ratio becomes larger. One end of link 178 is pin 183
Since the gear ratio detection member 158 is connected by the gear ratio detection member 158, the gear ratio detection member 158 is moved to the first position as the movable cone plate 22 moves.
When moving to the left in the figure, the link 178 rotates clockwise with the pin 185 on the other end side of the link 178 as a fulcrum. Therefore, the spool 174 is pulled back to the left, and the drive pulley 116 and the driven pulley 26 try to bring the gear ratio to a small state. With such operation, the spool 174,
The drive pulley 16 and the driven pulley 26 are stable at a predetermined gear ratio corresponding to the rotational position of the transmission motor 110. The same applies when the transmission motor 110 is rotated in the opposite direction. Therefore, when the speed change motor 110 is operated according to a predetermined speed change pattern, the speed change ratio changes accordingly, and by controlling the speed change motor 110, the speed change of the continuously variable transmission can be controlled.

The rotation position of the transmission motor 110 is determined according to the pulse number signal sent from the transmission control device. The pulse number signal from the shift control device is given according to a predetermined shift pattern.

Next, the operation of this embodiment will be described.

When the vehicle travels steadily in a state where the gear ratio is relatively small, the spool 174 of the gear shift control valve 112, the rod 182, the gear ratio detecting member 158, and the link 178 are in the state shown in FIG. When the transmission motor 110 is rapidly operated in this state to the high gear ratio side, the rod 182 moves to the right in FIG. 1 and the position at the highest gear ratio side (that is, the gear shift reference switch 298 is turned on). Position). For this reason,
The link 178 pivots clockwise in FIG. 1 with the pin 183 as a fulcrum, and moves the spool 174 of the shift control valve 112 largely rightward in FIG. This state is shown in FIG. The movement of the spool 174 completely opens the port 172b and communicates with the drain port 172a, so that the hydraulic pressure in the drive pulley cylinder chamber 20 is rapidly discharged. As the hydraulic pressure in the drive pulley cylinder chamber 20 is discharged, the movable conical plate 22 of the drive pulley moves to the higher gear ratio side, that is, to the left in FIG. 1, and finally reaches the position of the highest gear ratio. . This state is shown in FIG. Even when the movable conical plate 22 moves to the position on the maximum gear ratio side, the tapered portion 174b ′ provided on the land 174b of the spool 174 of the speed change control valve 112 does not exert a throttle effect on the port 172b. It is located in. Therefore, the hydraulic pressure in the drive pulley cylinder chamber 20 rapidly increases without being affected by the throttling effect until the movable cone plate 22 moves to the position with the large gear ratio, that is, until the gear shift to the large gear ratio side is completed. Continues to be discharged.
Therefore, shifting to the higher gear ratio side is extremely rapid.
As a result, even when the wheels are locked by the sudden braking and the drive pulley and the driven pulley do not rotate, the gear can be rapidly changed, and the V belt can be prevented from slipping even when it is re-driven after a short time. Occurrence can be prevented.

(G) Effect of the Invention As described above, according to the present invention, the hydraulic pressure of the drive pulley is discharged without being subjected to the throttling effect of the speed change control valve during a sudden speed change to the higher gear ratio side.
The shift to the higher gear ratio side is performed rapidly. As a result, it is possible to prevent the V-belt from slipping when re-driving from the shift to the higher gear ratio side.

[Brief description of drawings]

FIG. 1 is a diagram showing a shift control device for a continuously variable transmission according to the present invention, FIG. 2 is a diagram showing a skeleton diagram of the continuously variable transmission, and FIG. FIG. 4 is a view showing the speed change operation mechanism, and FIG. 4 is a view showing the speed change operation mechanism in a state in which the movable conical plate has moved to the higher speed ratio side. 16 …… Drive pulley, 24 …… V belt, 26 …… Drive pulley, 106 …… Shift control valve, 110 …… Shift motor, 158 ……
Gear ratio detection member, 172b ... Port, 174b ... Land (17
4b ', 174b "... tapered part), 178 ... link, 182 ...
…rod.

Claims (1)

[Claims] 1. A drive pulley and a driven pulley, each of which comprises a fixed cone plate and a movable cone plate, a V belt wound between the pulleys, a speed change motor, and a rod which moves in the axial direction in response to rotation of the speed change motor. And a speed change control valve capable of controlling the hydraulic pressure acting on the movable cone plates of both pulleys, and a rod, a speed change control valve and a speed change gear so that the movement of the movable cone plate detected by the speed ratio detecting member is fed back to the speed change control valve. In a shift control device for a continuously variable transmission having a link connecting ratio detection members, a port of a shift control valve connected to an oil passage communicating with a drive pulley and a land of a spool for controlling the open / closed state of this port are When the gear ratio detection member is at the highest gear ratio side and the rod moved by the gear shift motor is at the highest gear ratio side, the land of the spool is A shift control device for a continuously variable transmission, characterized in that the port is configured to be completely opened.