JPH07133858A - Transmission control device for continuously variable transmission - Google Patents

Abstract

PURPOSE:To smoothly change over a transmission and realize a failsafe condition at the time of selecting a backward travel by connecting a torque dividing clutch, when an output speed is higher than torque dividing clutch input speed, connecting a direct coupling clutch, when the output speed is lower, and holding the connected state of the torque dividing clutch for prohibiting the connection of the direct coupling clutch. CONSTITUTION:A transmission mode selector control means (n) connects a torque dividing clutch (h), when a speed detected with an output speed detection means (j) is equal to or higher than a speed detected with a torque dividing clutch input speed detection means (k), and selects torque dividing mode to control reverse, neutral and load side drive ranges within the transmission gear ratio control range of a continuously variable transmission (b). When the speed detected with the means (j) is lower than the speed detected with the means (k), the control means (n) connects a direct coupling clutch (i) and selects direct coupling mode to control a high side drive range with the transmission gear ratio control range of the the continuously variable transmission (b). Also, when a speed detected with a unit output speed direction detection means (m) is in backward travel mode, the connection of the clutch (h) is maintained and the connection of the clutch (i) is prohibited. According to this construction, smooth mode selection and a failsafe condition for the backward travel mode can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission control device for an infinite reduction ratio transmission, which is a combination of a continuously variable transmission and a planetary gear mechanism, and more particularly to a transmission mode switching control technique.

[0002]

2. Description of the Related Art Conventionally, as a shift control device for an infinite reduction ratio transmission, which is a combination of a continuously variable transmission and a planetary gear mechanism,
For example, the one described in US Pat. No. 5,504,028 is known.

In the above-mentioned conventional source, the infinite reduction ratio transmission in which the continuously variable transmission 1 and the planetary gear mechanism 26 are combined is provided in the middle of the transmission path from the unit input shaft 14 to the carrier of the planetary gear mechanism 26. A torque split clutch 25 and a direct coupling clutch 33 provided midway in the transmission path from the sun gear of the planetary gear mechanism 26 to the unit output shaft are provided, and the torque split clutch 25 is engaged to change the gear ratio of the continuously variable transmission 1. By controlling the total reduction ratio from a negative value (during reverse travel) to a positive value (during forward travel), the torque split mode including infinity of the transmission ratio and the direct coupling clutch 33 are engaged, and the total reduction ratio is zero. There is disclosed a device that performs gear shift control to obtain an optimum gear ratio according to a running state by switching between a direct coupling mode, which is a gear ratio of a stage transmission.

[0004]

However, in the above-described conventional shift control device for an infinite reduction ratio transmission, the transmission mode switching control does not make a determination as to the actual traveling state (forward or reverse) of the vehicle. Since the device switches from the torque split mode to the direct connection mode or from the direct connection mode to the torque split mode, the torque split mode may switch to the direct connection mode at the time of reverse travel, resulting in clutch burn or engine failure. To do.

The present invention has been made in view of the above problems. A first object of the present invention is to control the shift of an infinite reduction gear ratio transmission in which a continuously variable transmission and a planetary gear mechanism are combined. The object of the present invention is to achieve smooth transmission mode switching control and to realize fail-safe transmission mode switching when the vehicle is moving backward.

A second object is to achieve a smooth transmission mode switching control and a fail-safe transmission mode switching when the vehicle is moving backward by a cost-effective and reliable operation.

[0007]

In order to achieve the above-mentioned first object, in the speed change control device for an infinite reduction ratio transmission of the first invention, as shown in the claim correspondence diagram of FIG. 1, it is connected to a unit input shaft a. The continuously variable transmission b and the speed reducer c, and the sun gear are connected to the continuously variable transmission output shaft d, and the speed reducer output shaft e
A planetary gear mechanism g in which a carrier is connected to the unit output ring f and a ring gear is connected to the unit output shaft f, and a torque split clutch h provided in the middle of a transmission path from the unit input shaft a to the carrier of the planetary gear mechanism g. A direct coupling clutch i provided in the middle of the transmission path from the sun gear of the planetary gear mechanism g to the unit output shaft f, and a continuously variable transmission output speed detection means j for detecting the rotational speed of the continuously variable transmission output shaft d. A torque split clutch input rotation speed detection means k for detecting the input rotation speed of the torque split clutch h, a unit output rotation direction detection means m for detecting the rotation direction of the unit output shaft f, and a continuously variable transmission output. When the rotational speed is higher than the torque split clutch input rotational speed, only the torque split clutch h is engaged, and the continuously variable transmission output rotational speed is lower than the torque split clutch input rotational speed. Transmission mode switching control means n is provided for engaging only the direct coupling clutch i and retaining the engagement of the torque split clutch h and prohibiting the engagement of the direct coupling clutch i when the unit output rotation direction is the reverse direction. It is characterized by

In order to achieve the above-mentioned second object, the shift control device for an infinite reduction ratio transmission according to a second aspect of the present invention is the shift control device for an infinite reduction ratio transmission according to claim 1, wherein the output rotation of the continuously variable transmission is changed. The number detection means j and the torque split clutch input rotation speed detection means k are means by a pitot tube for converting the rotation speed into a pitot pressure, and the unit output rotation direction detection means m uses a pitot pressure generated only during reverse travel. It is a means using a pipe, and the transmission mode switching control means n is a transmission mode switching control valve which operates using each Pitot pressure as a signal pressure.

[0009]

The operation of the first invention will be described.

The transmission mode switching control is performed by the transmission mode switching control means n in the continuously variable transmission output speed detecting means j.
If the output speed of the continuously variable transmission from the higher than the input speed of the torque split clutch from the torque split clutch input speed detection means k, only the torque split clutch h is engaged, and the gear ratio control range by the continuously variable transmission b. The reverse range, the neutral range, and the low-side drive range are controlled in the torque split mode, and the continuously variable transmission output speed detection unit j detects the continuously variable transmission output speed as the torque split clutch input speed detection. When the rotational speed is lower than the torque split clutch input speed from the means k, only the direct coupling clutch i is engaged and the high side drive range is controlled between the speed ratio control ranges by the continuously variable transmission b.

In the above transmission mode switching control, when the unit output rotation direction from the unit output rotation direction detecting means m is the reverse direction, the rotation speed condition for setting the direct connection mode due to a failure of the continuously variable transmission b is satisfied. Even so, the engagement of the torque split clutch h is maintained, and the engagement of the direct coupling clutch i is prohibited.

Therefore, smooth transmission mode switching control can be achieved by comparing the rotational speeds, and the transmission mode does not switch to the direct connection mode when the vehicle is in reverse, so that fail-safe in reverse is realized.

The operation of the second invention will be described.

In the continuously variable transmission output rotational speed detecting means j and the torque split clutch input rotational speed detecting means k using the Pitot tube, a higher Pitot pressure is generated as the rotational speed becomes higher. Further, in the unit output rotation direction detecting means m by the pitot tube, pitot pressure is not generated when moving forward, and pitot pressure is generated only when moving backward.

When the transmission mode switching control valve operates with these Pitot pressures as signal pressure and the continuously variable transmission output speed is higher than the torque split clutch input speed, only the torque split clutch h is engaged due to the Pitot pressure difference. When the output speed of the continuously variable transmission is lower than the input speed of the torque split clutch, only the direct coupling clutch i is engaged due to the Pitot pressure difference, and the unit output rotation direction is the reverse direction. At this time, the valve position is such that the torque split clutch h holds the engagement by the pitot pressure and the direct connection clutch i does not engage.

Therefore, a cost-effective device which does not require a sensor, a controller, and an actuator, and moreover, a reliable operation in which the cause of electrical failure is eliminated,
The smooth transmission mode switching control action of the first aspect of the invention and the fail safe in reverse travel are realized.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

First, the structure will be described.

FIG. 2 is an overall block diagram showing an infinite reduction gear ratio transmission to which the gear shift control device of the embodiments corresponding to the present invention described in claims 1 and 2 is applied.

In FIG. 2, the power transmission system includes a continuously variable transmission 2 and a speed reducer 3 connected to a unit input shaft 1.
A planetary gear mechanism 5 in which a sun gear 5a is connected to the continuously variable transmission output shaft 4, a carrier 5b is connected to the reduction gear output shaft 6, and a ring gear 5c is connected to the unit output shaft 7.
A torque split clutch A provided in the middle of the reduction gear output shaft 6 from the unit input shaft 1 to the carrier 5b of the planetary gear mechanism 5 and a transmission path from the sun gear 5a of the planetary gear mechanism 5 to the unit output shaft 7 Directly connected clutch B provided
It has and.

The unit input shaft 1 is connected to an engine mounted on a vehicle.

As the continuously variable transmission 2, a V-belt type continuously variable transmission or a toroidal type continuously variable transmission is used.

The reduction gear 3 is set so that its reduction ratio matches the maximum reduction ratio of the continuously variable transmission 2.

The reduction gear output shaft 6 has a clutch split shaft A and a clutch input shaft 6a and a clutch output shaft 6b.
It is composed of

The unit output shaft 7 is connected to the left and right drive wheels via a differential gear.

In FIG. 2, the transmission mode switching hydraulic control system includes a continuously variable transmission output speed detection pitot tube 10 (continuously variable transmission output speed detection means for converting the continuously variable transmission output speed into pitot pressure). j)), a torque split clutch input speed detection pitot tube 11 (corresponding to torque split clutch input speed detection means k) for converting the torque split clutch input speed into pitot pressure, and pitot pressure is generated only during reverse travel. Unit output rotation direction detecting pitot tube 12 (corresponding to unit output rotation direction detecting means m), transmission mode switching control valve 13 (corresponding to transmission mode switching control means n) which operates by using each pitot pressure as a signal pressure, and a regulator. The valve 14 and the oil pump 15 are provided.

Next, the operation will be described.

[Torque Split Mode] The torque split mode is realized by engaging the torque split clutch A and releasing the direct coupling clutch B.

In this state, the rotation speed of the carrier 5b is constant when the rotation speed of the unit input shaft is constant. Therefore, the rotation speed of the unit output shaft 7 is the rotation speed of the output shaft of the continuously variable transmission 2 = By shifting the continuously variable transmission 2 from the speed increasing side to the speed reducing side by the rotation speed of the sun gear 5a, the rotation speed of the ring gear 5c that becomes the unit output shaft rotation speed is changed from reverse (negative) to stop (0). After that, it is possible to shift to the normal rotation.

That is, as shown by the solid line characteristics in FIG.
CVT ratio (stepless speed change ratio) is 0.4 (acceleration side) to 2.
The reverse range, the neutral range, and the low-side drive range are controlled between 0 (deceleration side), and the speed change ratio is represented by an IVT ratio including an infinite reduction ratio.

[Direct Connection Mode] The direct connection mode is realized by releasing the torque split clutch A and engaging the direct connection clutch B.

In this state, the speed reducer 3 and the planetary gear mechanism 5 do not participate in gear shifting, and the rotation speed of the unit output shaft 7 becomes the output shaft rotation speed of the continuously variable transmission 2. That is, the gear ratio in forward rotation can be obtained by performing the gear shift control on the continuously variable transmission 2.

That is, as shown by the alternate long and short dash line characteristic in FIG. 3, the CVT ratio (continuously variable transmission ratio) is 2.0 (deceleration side) to
The high-side drive range is controlled between 0.4 (acceleration side), and the gear ratio thereof matches the CVT ratio of the continuously variable transmission 2.

[Pitot Pressure Generating Operation] In the continuously variable transmission output speed detection pitot tube 10, as shown in FIG. 4 (a), the sun gear rotational speed NS (= continuously variable transmission output speed) increases. As a result, a Pitot pressure PNS that rises as a quadratic function curve is obtained.

In the torque split clutch input speed detection pitot tube 11, as shown in FIG.
As the C (= torque split clutch input speed) increases, the pitot pressure PNC that increases in a quadratic function curve is obtained.

In the unit output rotation direction detecting pitot tube 12, as shown in FIG. 5, the pitot which rises like a quadratic function curve as the ring gear rotation speed NR (= unit output shaft rotation speed) rises only during reverse travel. The pressure PNR is obtained, and there is no Pitot pressure when moving forward.

That is, as shown in FIG. 6, the hole of the unit output rotation direction detecting pitot tube 12 is set to the ring gear 5 when moving backward.
Since the c is arranged to receive the oil only in the rotating direction, the pitot pressure is generated only in the reverse travel. Therefore, the hydraulic pressure information can be used to determine whether the pitot pressure is moving forward or backward.

[Transmission Mode Switching Control Operation] First, as shown in FIGS. 7 and 8, the transmission mode switching control valve 13 has a spool 13a, a carrier pressure port 13b, a drain port 13c, and a clutch B pressure port 13d. A line pressure port 13e, a clutch A pressure port 13f, a drain port 13g, a sun gear pressure port 13h, and a ring gear pressure port 13i.

In the neutral range, as shown in FIG. 3, the gear ratio of the continuously variable transmission 2 is set to the speed increasing side of about 0.75. Therefore, the relationship between the sun gear speed NS and the carrier speed NC is NS> NC, and the relationship between the pitot pressure PNS and the pitot pressure PNC is PNS> PNC. As shown in the lower portion of FIG. The line pressure PL generated by the regulator valve 14 in the state of being pressed against the left end is supplied from the line pressure port 13e communicating with each other to the torque split clutch A via the clutch A pressure port 13f, and the torque split clutch A is released. It is concluded. Further, the direct coupling clutch B is brought into the released state by the clutch B pressure port 13d communicating with the drain port 13c, and the torque split mode is realized.

When the neutral range is selected to the drive range, the gear ratio of the continuously variable transmission 2 shifts from the speed increasing side to the speed reducing side as shown in FIG.
Until it reaches 0, the relationship between the Pitot pressure PNS and the Pitot pressure PNC is maintained as PNS> PNC, and as shown in the lower part of FIG. 7, the torque split mode with the spool 13a pressed against the left end of the drawing. Is maintained. In this torque split mode, the gear ratio control by the continuously variable transmission 2 realizes the low-side drive range in which the gear ratio is controlled from the infinite reduction ratio to the reduction ratio 2.0.

The point at which the speed reduction ratio of the continuously variable transmission 2 becomes 2.0 is the clutch switching point. At this time, the relationship between the sun gear speed NS and the carrier speed NC is NS = NC, and the Pitot pressure The relationship between PNS and Pitot pressure PNC is PNS = P
NC, and as shown in the upper part of FIG. 7, the spool 13a moves to the right in the drawing, the supply of the line pressure PL generated by the regulator valve 14 to the torque split clutch A is cut off, and the direct coupling clutch B The communication with the drain pressure port 13c is also cut off.

Further, when the reduction ratio of the continuously variable transmission 2 exceeds 2.0, the relationship between the sun gear speed NS and the carrier speed NC becomes NS <NC, and the pitot pressure PNS and the pitot pressure P
The relationship with NC is PNS <PNC, the spool 13a is pressed against the right end of the drawing as shown in the upper part of FIG. 8, and the line pressure PL generated by the regulator valve 14 is the line pressure communicating with each other. It is supplied from the port 13e to the direct coupling clutch B via the clutch B pressure port 13d, and the direct coupling clutch B is engaged. On the other hand, the torque split clutch A is released by the clutch A pressure port 13f communicating with the drain port 13g, and the transmission mode is switched from the torque split mode to the direct connection mode. In this direct connection mode, the high-side drive range in which the gear ratio is controlled from 2.0 on the deceleration side to 0.4 on the speed increasing side is realized by the gear ratio control by the continuously variable transmission 2.

When the neutral range is selected to the reverse range, the torque split mode is maintained as it is, but at this time, due to the generation of the pitot pressure PNR from the unit output rotation direction detecting pitot tube 12, the lower part of FIG. 8 is shown. As described above, the spool 13a is pressed toward the left side of the drawing by the pitot pressure PNR in addition to the pitot pressure PNS, the pitot pressure PNC, and the differential pressure, and even if the pitot pressure relation of PNS <PNC is established, the torque split clutch A is engaged. A spool position is ensured that is held and prohibits the engagement of the direct coupling clutch B.

Next, the effect will be described.

(1) In a transmission control device for an infinite reduction gear ratio transmission in which the continuously variable transmission 2 and the planetary gear mechanism 5 are combined, the relationship between the pitot pressure PNS and the pitot pressure PNC is PNS> PNC.
At the time of, the torque split mode is set, and the relationship between the pitot pressure PNS and the pitot pressure PNC is P via the clutch switching point of PNS = PNC.
Transmission mode switching control that secures a spool position that holds the engagement of the torque split clutch A by generating the pitot pressure PNR from the unit output rotation direction detection pitot tube 12 when the vehicle is in reverse mode in the torque split mode when NS <PNC Since the device is provided with the valve 13, it is possible to achieve smooth transmission mode switching control and to realize a fail-safe transmission mode switching when the vehicle is moving backward.

(2) The transmission mode switching control valve 13 is provided with the pitot pressure PNS from the continuously variable transmission output speed detection pitot tube 10, the torque split clutch input rotation speed detection pitot tube 11 and the unit output rotation direction detection pitot tube 12. , Pitot pressure PNC,
Since the pitot pressure PNR is used as the operation signal pressure, it is possible to achieve smooth transmission mode switching control by cost-effective and reliable operation, and to realize a fail-safe transmission mode switching when the vehicle is moving backward. You can

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, each rotation number and rotation direction are detected by the Pitot pressure using the Pitot tube. However, a rotation sensor or a rotation direction sensor is used, and a sensor signal is input to transmit the transmission mode. The switching process may be performed electronically.

[0049]

According to the present invention as set forth in claim 1, in a speed change control device for an infinite reduction ratio transmission in which a continuously variable transmission and a planetary gear mechanism are combined, the continuously variable transmission output rotational speed is a torque division. If the clutch input speed is higher than the clutch input speed, only the torque split clutch is engaged.If the continuously variable transmission output speed is lower than the torque split clutch input speed, only the direct coupling clutch is engaged, and the unit output rotation direction is the reverse direction. In this case, since the device is provided with the transmission mode switching control means for holding the engagement of the torque split clutch and prohibiting the engagement of the direct coupling clutch, a smooth transmission mode switching control can be achieved and the transmission mode can be achieved when the vehicle reverses. The effect that the fail-safe of switching can be realized is obtained.

According to a second aspect of the present invention, in the speed change control device for an infinite reduction gear ratio transmission according to the first aspect, the continuously variable transmission output speed detecting means and the torque split clutch input speed detecting means are provided. The unit output rotation direction detecting means is a means using a pitot tube that uses the pitot pressure that is generated only in reverse, and the transmission mode switching control means is a signal pressure for each pitot pressure. Since the transmission mode switching control valve is operated as the above, a smooth transmission mode switching control can be achieved by a cost-effective and reliable operation, and at the same time, a failsafe of the transmission mode switching can be realized when the vehicle is moving backward. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a shift control device for an infinite reduction gear transmission according to the present invention.

FIG. 2 is an overall block diagram showing an infinite reduction ratio transmission to which the shift control device of the embodiment is applied.

FIG. 3 is a diagram illustrating a relationship between each transmission mode and a gear ratio in the infinite reduction gear transmission of the embodiment.

FIG. 4 is a characteristic diagram of each Pitot pressure in the apparatus of the embodiment.

FIG. 5 is a Pitot pressure characteristic diagram during backward movement and forward movement in the apparatus of the embodiment.

FIG. 6 is a diagram for explaining the pitot pressure generating action in the unit output rotation direction detecting pitot tube of the embodiment apparatus.

FIG. 7 is a valve operation explanatory diagram of the transmission mode switching control valve of the embodiment apparatus.

FIG. 8 is a valve operation explanatory diagram of the transmission mode switching control valve of the embodiment apparatus.

[Explanation of symbols]

 a unit input shaft b continuously variable transmission c speed reducer d continuously variable transmission output shaft e speed reducer output shaft f unit output shaft g planetary gear mechanism h torque split clutch i direct coupling clutch j continuously variable transmission output speed detection means k Torque split clutch input rotation speed detection means m Unit output rotation direction detection means n Transmission mode switching control means

Claims (2)

[Claims] 1. A continuously variable transmission and a speed reducer connected to a unit input shaft, a sun gear connected to the continuously variable transmission output shaft, a carrier connected to the speed reducer output shaft, and a ring gear connected to the unit output shaft. Connected planetary gear mechanism, torque split clutch provided in the transmission path from the unit input shaft to the carrier of the planetary gear mechanism, and provided in the transmission path from the sun gear of the planetary gear mechanism to the unit output shaft. A direct coupling clutch, a continuously variable transmission output speed detection means for detecting the rotation speed of the continuously variable transmission output shaft, a torque split clutch input rotation speed detection means for detecting an input rotation speed of the torque split clutch, A unit output rotation direction detecting means for detecting the rotation direction of the unit output shaft, and a torque converter when the continuously variable transmission output rotation speed is higher than the torque split clutch input rotation speed. Only the split clutch is engaged, only the direct clutch is engaged when the continuously variable transmission output speed is lower than the torque split clutch input speed, and the torque split clutch is engaged when the unit output rotation direction is the reverse direction. And a transmission mode switching control means for holding the clutch and prohibiting the engagement of the direct coupling clutch, and a shift control device for an infinite reduction gear ratio transmission. 2. The shift control device for an infinite reduction ratio transmission according to claim 1, wherein the continuously variable transmission output rotation speed detection means and the torque split clutch input rotation speed detection means convert the rotation speed into pitot pressure. The unit output rotation direction detecting unit is a unit using a Pitot tube that uses a Pitot pressure that is generated only during reverse travel, and the transmission mode switching control unit is a transmission mode that operates using each Pitot pressure as a signal pressure. A shift control device for an infinite reduction ratio transmission, which is a switching control valve.