JPH09166191A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent switching of two modes in a given pulley ratio region and to prevent the occurrence of reverse and over revolution, in a continuously variable transmission having a belt type continuously variable gear shifter and a planetary gear and achieving switching of a low mode and a high mode through clamp change of a clutch. SOLUTION: A sensor shoe 65 is provided to move in linkage with the moving sheave 7b of a primary pulley 7, and a recessed part 65a and other protrusion part than the recessed part are formed on the sensor shoe 65. Further, recessed parts 60a and 60b are formed in the spool of a low high control valve 60, and an interlock rod 66 is arranged between the sensor shoe 65 and the valve 60. In a given pulley ratio region, for example, the low pulley ratio side, in the low mode and the high mode, a moving sheave 65 is moved to the O/D side, the rod 66 has a base end part 66a moved over the protrusion of the sensor shoe 65 and a tip part 65b engaged with the recessed part 60a or 60b of the valve 60 to mechanically lock the valve 60. This constitution eliminates switching of a mode through clamp exchange of low clutches CL and CN.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission using a belt type continuously variable transmission formed by winding a belt around a primary pulley and a secondary pulley each having two sheaves, and particularly to a transmission for an automobile. The present invention relates to a mode control of a continuously variable transmission in which the belt type continuously variable transmission and a planetary gear are combined to enable a low mode and a high mode for one pulley ratio.

[0002]

2. Description of the Related Art Recently, as a transmission for an automobile, a continuously variable transmission constructed by combining a belt type continuously variable transmission and a planetary gear has been attracting attention in order to further improve the fuel consumption rate and the running performance. Such a continuously variable transmission is described, for example, in JP-A-62-188841 and JP-A-6-331000.

A belt type continuously variable transmission in this continuously variable transmission is constructed by winding a belt between a primary pulley and a secondary pulley, each of which has a fixed sheave and a movable sheave, and a clamping force of the belt by the movable sheave. The pulley ratio is reduced by increasing the primary side and the pulley ratio is increased by increasing the secondary side. Then, according to the value of the pulley ratio, the rotation of the sun gear of the planetary gear and the rotation of the carrier are appropriately adjusted, whereby the rotation of the output shaft integral with the ring gear is normally rotated, stopped, and reversely rotated, respectively, in the forward movement state, Neutral state,
The reverse state is set.

By further incorporating two clutches into the above-mentioned belt type continuously variable transmission and grabbing these clutches, a low mode having a high torque ratio and a high mode having a low torque ratio in a limited pulley ratio region. It is also known to achieve.

[0005]

According to the above-mentioned continuously variable transmission, for example, from the high ratio of the pulley ratio to the low ratio, in the low mode, low speed forward movement, neutral movement,
Reverse travel corresponds, and for the same pulley ratio, in high mode, progressively faster high speed travel.
That is, two modes, a low mode and a high mode, correspond to an arbitrary pulley ratio. For this reason, if the clutch is not re-clipped in the predetermined pulley ratio region, jump shift occurs, switching from high-speed forward to reverse and unexpected reverse is performed, or high-speed forward to low-speed. There is a problem in that the engine is switched to forward movement and engine overrev occurs.

Therefore, an object of the present invention is to provide a continuously variable transmission which prevents jump shifts in a predetermined pulley ratio region and eliminates the above-mentioned unexpected reverse travel and engine overrev. is there.

[0007]

The present invention according to claim 1 has been made in view of the above circumstances, and includes an input shaft that interlocks with an engine output shaft, and an output shaft that interlocks with wheels.
The first pulley on the input shaft side, the second pulley on the output shaft side, and the first pulley on the output shaft side are interposed between the input / output shafts.
And a planetary gear interposed between the input / output shafts and a belt type continuously variable transmission having a belt wound around the second pulley, and changing a torque transmission path between the input / output shafts. As a result, in the continuously variable transmission capable of coping with the low mode having a high torque ratio and the high mode having a low torque ratio, with respect to an arbitrary pulley ratio in the pulley ratio region of the belt type continuously variable transmission, A low / high switching means capable of switching between a high mode and a high mode, a detecting means for detecting a pulley ratio of the belt type continuously variable transmission, and a pulley ratio detected by the detecting means in a predetermined pulley ratio region, A restriction unit for restricting the operation of the low-high switching unit to prohibit switching between the low mode and the high mode.

According to the second aspect of the present invention, there is provided a first clutch which has a first hydraulic servo and which is engaged by supplying hydraulic pressure to the first hydraulic servo to achieve the low mode. And a second clutch that has a second hydraulic servo and is engaged by supplying hydraulic pressure to the second hydraulic servo to achieve the high mode, the low-high switching means, A low-high switching valve for switching the supply of hydraulic pressure to the first and second hydraulic servos is provided.

In the present invention according to claim 3, the low-high switching valve has a spool for switching a hydraulic pressure supply path to the first and second hydraulic servos based on an output signal from the detecting means. However, it is characterized in that the regulation means has a lock member that locks the spool when the pulley ratio is in the predetermined pulley ratio region.

According to a fourth aspect of the present invention, each of the first and second pulleys has a movable sheave that changes the pinching pressure on the belt to change the pulley ratio, and the detecting means includes: A concavo-convex portion is formed at which one end of the locking member is engaged and disengaged, and a position detecting member that moves in conjunction with one of the movable sheaves is provided. By engaging and disengaging, the other end locks or unlocks the spool.

According to a fifth aspect of the present invention, the planetary gear includes a first rotating element connected to the input shaft, a second rotating element connected to the second pulley, and the output shaft. A third rotating element connected to
The first clutch connects the input shaft and the first rotating element, and the second clutch rotates any two of the first, second, and third rotating elements. It is characterized by connecting elements.

[Operation] Based on the above configuration, the low / high switching means for switching between the low mode and the high mode is operated by the restricting means when the pulley ratio detected by the detecting means is within a predetermined pulley ratio region. It is regulated and switching is prohibited. Therefore, when the pulley ratio falls within the predetermined pulley ratio region in the low mode, the low mode is maintained and it becomes impossible to switch from the low mode to the high mode. When the pulley ratio region is entered, the high mode is maintained and it becomes impossible to switch from the high mode to the low mode. In any case, the mode at the time of entering the predetermined pulley ratio region is maintained, and switching to another mode is prohibited.

The above-mentioned predetermined pulley ratio region is a region in which the difference in rotational speed becomes large when the high mode is switched to the low mode, and a region in which the vehicle reverses from forward to reverse. That is, it is preferable to set the output shaft in a region in which the output shaft rotates at a high speed, based on the high mode.

[0014]

According to the first aspect of the present invention, switching from the low mode to the high mode or vice versa is prohibited in a predetermined pulley ratio region, and reverse rotation from forward to reverse or engine overrev is caused. Can be effectively prevented.

According to the second aspect of the present invention, by restricting the operation of the low / high switching valve, the operation of the hydraulic servo for engaging the clutch is restricted to prevent the two clutches from being grabbed and set to the low mode. Prevents switching between high mode. The object of the present invention can be achieved by a simple measure of restricting the operation of the low / high switching valve.

According to the third aspect of the present invention, since the spool of the low / high switching valve is mechanically locked by the lock member to prevent mode switching, the operation is reliable.

According to the fourth aspect of the present invention, the spool is locked and locked by the position detecting member that interlocks with the movement of the movable pulley that moves according to the change of the pulley ratio, and the locking member that is directly actuated by the position detecting member. Since the cancellation is performed, the operation becomes more reliable.

According to the fifth aspect of the present invention, switching between the low mode and the high mode, and forward, neutral and reverse in the low mode are performed by re-grabbing the first and second clutches and changing the pulley ratio. Can be easily realized by.

[0019]

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

First, the power transmission mechanism of the continuously variable transmission according to the present invention will be described with reference to FIG. An in-vehicle automatic continuously variable transmission (hereinafter referred to as "continuously variable transmission") 1 includes a first shaft 3, a second shaft 5 aligned with an engine crankshaft 2, and a third shaft 6 (a, b) aligned with a front axle. ) Has a first
A primary (first) pulley 7 is supported on the shaft 3, and a secondary (second) pulley 9 is supported on the second shaft 5, and a belt 10 is wound around these pulleys 7, 9. Thus, the belt type continuously variable transmission 11 is configured.

The first shaft 3 is connected to the engine crankshaft 2 via a damper 12 to form an input shaft. The input shaft 3 has an input side member 1 of the low clutch C _L.
3, the output side member 15 is rotatably supported, and the output side member 15 is integrally connected with a primary side sprocket 16 which constitutes a power transmission means. A fixed sheave 7a of the primary pulley 7 is fixed to the input shaft 3, and an oil pump 17 is connected to the tip of the fixed sheave 7a. A movable sheave 7b moves axially in the fixed sheave 7a. Supported as possible.

A secondary pulley 9 is rotatably supported on the second shaft 5, and the secondary pulley 9 includes a fixed sheave 9a, a movable sheave 9b and a fixed sheave that are axially movably supported by the fixed sheave. It has the secondary shaft 9c connected integrally. Further, a high clutch C _H is provided between the second shaft 5 and the secondary shaft 9c, a planetary gear 19 is arranged on the second shaft 5, and the secondary side sprocket 20 is rotatable. Supported by. An output gear 21 is fixed to one end of the second shaft 5 to form an output shaft.

The planetary gear 19 is a sun gear 19
s, a ring gear 19r and a carrier 19 rotatably supporting a pinion 19p meshing with both gears.
and a single-pinion planetary gear having c.
Then, the sun gear 19s is connected to the secondary shaft 9c.
To form a second rotating element, the ring gear 19r is connected to the output shaft 5 to form a third rotating element, and the carrier 19c forms the secondary sprocket 2
It is connected to 0 to form the first rotating element. Also,
Primary side and secondary side sprockets 16, 20
A winding body 22 such as a silent chain, a roller chain or a timing belt is wound around the.

The gear 21 fixed to the output shaft 5 meshes with the large gear 23a of the reduction gear unit 23, and the small gear 23b of the unit meshes with the ring gear 24 of the differential device 25, The differential device 25 outputs differential rotations to the left and right axle shafts 6a and 6b forming the third shaft.

Next, the operation of the continuously variable transmission 1 based on the power transmission mechanism will be described with reference to FIGS. 1, 2, 3, 4, and 5.
It is explained along. The rotation of the engine crankshaft 2 is transmitted to the input shaft 3 via the damper 12. In the low mode (L mode) in which the low clutch C _L is connected and the high clutch C _H is disconnected, the rotation of the input shaft 3 is transmitted to the primary pulley 7 and the primary side sprocket 16, It is transmitted to the carrier 19c of the planetary gear 19 via the power transmission device 26 including the winding body 22 and the secondary side sprocket 20.
On the other hand, the rotation of the primary pulley 7 is continuously changed and transmitted to the secondary pulley 9 by appropriately adjusting the pulley ratio of the primary and secondary pulleys by an axial force actuating means such as a hydraulic servo which will be described later. The variable speed rotation of the pulley 9 is the sun gear 19s of the planetary gear 19.
Is transmitted to

In the planetary gear 19, as shown in the velocity diagram of FIG. 2, the carrier 19c to which the constant speed rotation is transmitted via the power transmission device 26 becomes a reaction force element, and the belt type continuously variable transmission (CVT). ) 11 continuously variable speed rotation is transmitted to the sun gear 19s, and the rotations of the carrier and the sun gear are combined to output the output shaft 5 via the ring gear 19r.
Is transmitted to At this time, since the ring gear 19r, which is a rotating element other than the reaction force supporting element, is connected to the output shaft 5, the planetary gear 19 causes torque circulation, and the sun gear 19s and the carrier 19c rotate in the same direction. The output shaft 5 rotates in the forward rotation (Lo) and reverse rotation (Rev) directions with zero rotation in between. That is, based on the torque circulation, when the output shaft 5 rotates in the forward (forward) direction,
In the belt type continuously variable transmission 11, torque is transmitted from the secondary pulley 9 to the primary pulley 7, and torque is transmitted from the primary pulley 7 to the secondary pulley 9 when the output shaft rotates in the reverse (reverse) direction.

In the high mode (H mode) in which the low clutch C _L is disengaged and the high clutch C _H is engaged, the transmission to the planetary gear 19 via the power transmission device 26 is cut off, The planetary gear 19
Is brought into an integrated rotation state by engagement of the high clutch C _H. Therefore, the rotation of the input shaft 3 is transmitted to the output shaft 5 exclusively through the belt type continuously variable transmission (CVT) 11 and the high clutch C _H. That is, the CVT 11 transmits power from the primary pulley 7 to the secondary pulley 9.
Further, the rotation of the output shaft 5 is transmitted to the differential device 25 via the output gear 21 and the reduction gear unit 23, and is transmitted to the left and right front wheels via the left and right axle shafts 6a and 6b.

As shown in the velocity diagram of FIG. 2, the output torque diagram of FIG. 3, the output rotational speed diagram of FIG. 4, and the clutch engagement table of FIG. 5, in the low mode, the belt type continuously variable transmission is used. The device (hereinafter referred to as "CVT") 11 has a limit (O / D) in the acceleration direction.
2) (the position of line a in FIG. 2), the sun gear 19s is rotated at the maximum speed, so that the carrier 19 having a constant rotation speed is
The ring gear 19r is reversely rotated with respect to the rotation of c, and the reverse rotation (REV) is transmitted to the output shaft 5. And CVT11
Shifts in the deceleration (U / D) direction, the rotational speed of the reverse rotation decreases, and at the predetermined pulley ratio determined by the gear ratio of the planetary gear 19 and the power transmission device 26, the output shaft 5
Becomes the neutral position (NEU) where the rotation speed of is zero. Further, when the CVT 11 shifts in the deceleration direction, the ring gear 19r is switched to the forward rotation direction, and the forward rotation, that is, the forward rotation is transmitted to the output shaft 5. At this time, as is apparent from FIG. 3, in the vicinity of the neutral position NEU, the torque of the output shaft 5 diverges infinitely.

Next, the CVT 11 is in the deceleration direction (U / D).
At the end, the high clutch C _H is connected and switched to the high mode. Further, as shown in FIGS. 3 and 4, the output torque and the output rotation speed are continuous at the pulley ratio at which the low mode and the high mode are switched. In the high mode, the output rotation of the CVT 11 remains unchanged from the output shaft 5
Therefore, in the velocity diagram of FIG. 2, it becomes a line parallel to the horizontal axis as shown in b. And this time, CVT
As the gear 11 is shifted in the speed increasing (O / D) direction, the rotation of the output shaft 5 is also changed in the speed increasing direction, and the transmission torque is reduced accordingly. Note that λ in FIG. 2 is the number of teeth Z of the sun gear.
It is a ratio (Zs / Zr) between s and the number of teeth Zr of the ring gear.

Next, an embodiment of a hydraulic control mechanism for a continuously variable transmission according to the present invention will be described.

Primary and secondary pulleys 7, 9
As shown in FIG. 6, the movable sheaves 7b and 9b are axially movably supported by the boss portions 7c and 9c of the fixed sheaves 7a and 9a via ball splines 30 and 31, respectively. , 9b are respectively provided with hydraulic servos 32, 33 constituting axial force actuating means for exerting an axial force on the pulleys. Both hydraulic servos 3
2, 33 are partition members 35, 36 and cylinder members 37, 39 fixed to the fixed sheave boss portions 7c, 9c.
And the drum members 40 and 41 and the second piston members 42 and 43 fixed to the rear surfaces of the movable sheaves 7b and 9b, and the partition members 35 and 36 are the drum members 40 and 4.
1 is oil-tightly fitted to the first piston member 42,
43 is a cylinder member 37, 39 and a partition member 35, 3
6 oil-tightly fitted to the first hydraulic chambers 45, 4 respectively.
6 and the second hydraulic chambers 47, 49 have a double piston structure.

The first hydraulic chambers 45 and 46 in the hydraulic servos 32 and 33 are respectively provided with movable sheaves 7.
The back surfaces of b and 9b form a piston surface, and the effective pressure receiving areas of the piston surface are equal on the primary side and the secondary side. Further, oil passages 50, 51, 52, 53 communicating with the first hydraulic chambers 45, 46 and the second hydraulic chambers 47, 49 are formed in the primary and secondary fixed sheave boss portions 7c, 9c, respectively. A spring 55 for preloading is contracted in the first hydraulic chamber 45 of the primary hydraulic servo 32.

Further, the hydraulic control mechanism (means) 54 of the present embodiment, as shown in FIG. 7, serves as a primary regulator valve 56, a ratio control valve 57, a downshift relief valve 58, a manual valve 59 and a low / high switching means. Low-high control valve (low-high switching valve) 60 (see FIG. 8), low clutch relief valve 61, clutch modulation valve 6
2, the ratio sensing valve 63,
A sensor shoe 65 as detecting means (position detecting member),
An interlock rod 66 is provided as a restricting means (lock member).

The low / high control valve 60 is turned on or off by a solenoid valve (not shown) based on a pulley ratio obtained by calculating the number of rotations of both pulleys 7 and 9.
ON / O of the solenoid valve when a signal is output
Spool 6 that switches the hydraulic pressure supply path by FF operation
0c, and the spool 60c has recesses 60a, 60
b and other convex portions.

The sensor shoe 65 includes the primary pulley 7
It is slidably supported by a guide member 67 arranged in parallel with the axis of. 2 from the sensor shoe 65
Book connecting portions 65b and 65c are projected, one connecting portion 65b is engaged with the movable sheave 7b of the primary pulley 7, and the other connecting portion 65c is engaged with the above ratio sensing valve 63. ing. Therefore, when the movable sheave 7b moves along the axis in the O / D direction or the U / D direction, the amount of movement is directly transmitted to the ratio sensing valve 63 via the sensor shoe 65.

Further, the sensor shoe 65 has a recess 65a.
And other convex portions are formed, and the base end portion (one end) 66 of the interlock rod 66 is formed in the concave portion 65a.
a is disengaged. The interlock rod 66 is arranged so as to pass through the valve body, and the tip portion (the other end) 66 b of the interlock rod 66 is provided at the low-high control valve 6.
It is disengaged from the recesses 60a and 60b of 0. Note that, in FIG. 7, the interlock rod 66 has a base end portion 66.
Although "a" and the tip portion 66b are shown separately, they are actually integrally formed. Further, when the base end portion 66a of the interlock rod 66 is engaged with the recessed portion 65a of the sensor shoe 65, the tip end portion 66b is not engaged with any of the recessed portions 60a and 60b of the low-high control valve 60, and thus the low-high control valve 60 is low. The sensor shoe 65 comes into contact with the convex portion on the surface of the control valve 60, and conversely, the base end portion 66a comes off the concave portion 65a of the sensor shoe 65.
The tip portion 66b is configured to engage with either of the concave portions 60a and 60b of the low-high control valve 60 when in contact with the convex portion on the surface.

Next, the operation of the hydraulic control mechanism 54 having the above structure will be described with reference to FIG.

In the following, (1) D range-L mode (drive range low mode), (2) D range-H mode (drive range high mode), (3) R (reverse) range, (4 ) The N (neutral) and P (parking) ranges will be described in this order. However, for (1) and (2), the first pulley ratio A when the neutral state is reached
The second pulley ratio B, which has a larger pulley ratio than (see FIG. 4)
With the boundary as the boundary, the control is changed in each of a region where the pulley ratio is larger (left side in the figure) and a region where the pulley ratio is smaller than this (right side in the figure). By changing this control,
As will be described later, in the region of the second pulley ratio B or less,
Downshifts in the D range-L mode and the R range are prohibited, and in the same range below the second pulley ratio B, jumping from the D range-H mode to the D range-L mode and the R range is prohibited. I am trying.

First, in any of the modes (1) to (4), as shown in FIG. 7, the hydraulic pressure from the oil pump 17 is appropriately adjusted by the primary regulator valve 56 and output from the output port v. At the same time, they are sent to the first hydraulic chambers 45, 46 of the hydraulic servos 32, 33 to be controlled to equal pressure, and further sent to the clutch modulation valve 62. The output hydraulic pressure from the clutch modulation valve 62 is selectively supplied to the low clutch C _L or the high clutch C _H except in the N and P ranges of (4). Hereinafter, description will be made in order with reference to the sandwiching pressure balance tables of FIGS. 4, 7, and 9. (1) D range-L mode The same hydraulic pressure is supplied to the first hydraulic chambers 45 and 46, the low clutch C _L is connected, and further, the hydraulic pressure is supplied to the second hydraulic chamber 49 in the upshift. Further, in the downshift, the hydraulic pressure is supplied to the second hydraulic chamber 47, but at the second pulley ratio B or less, this supply is stopped and the downshift is prohibited.

That is, in the upshift, the manual valve 59 is operated to the D range position so that the ports a and b, c and d, and e and f communicate with each other, and the low / high control valve 60 is set to the L mode position. And ports h and i, j and k, l and m communicate with each other,
The port g is switched and held so as to communicate with the drain port Ex.

Therefore, the hydraulic pressure from the clutch modulation valve 62 is applied to the low clutch C _L by the ports a and b of the manual valve 59, the ports h and i of the low / high control valve 60, and the port n of the low clutch relief valve 61. And o, the low clutch C _L is engaged. Further, the hydraulic pressure from the output port v of the primary regulator valve 56 is gradually increased by the ratio control valve 57 so as to reach the hydraulic pressure corresponding to the target pulley ratio, and the ports p and q, the port c of the manual valve 59, and It is supplied to the second hydraulic chamber 49 via the ports j and k of the low and high control valve 60. In this state, the high clutch C _H is in a released state by being communicated with the drain port Ex from the port g of the low-high control valve 60, and the second hydraulic chamber 4 of the primary hydraulic servo 32 is in communication.
7 communicates with the drain port Ex via the ports m and l of the low / high control valve 60, the ports f and e of the manual valve 59, and the port s of the downshift relief valve 58.

As a result, the low clutch C _L is connected and the CVT 11 is connected to the first and second hydraulic chambers 46, 4
Secondary side hydraulic servo 33 in which hydraulic pressure acts on both 9
The axial force due to becomes higher than the axial force due to the primary side hydraulic servo 32 in which the hydraulic pressure acts only on the first hydraulic chamber 45, the axial force is gradually increased, and the pulley ratio is increased.
At this time, the movable sheave 7b of the primary pulley 7
Move to / D side. In this state, the engine torque transmitted from the input shaft 3 to the carrier 19c of the planetary gear 19 via the low clutch C _L and the power transmission device 26 is C by the predetermined pulley ratio via the sun gear 19s.
It is taken out from the output shaft 5 via the ring gear 19r while being regulated by the VT 11.

When the upshift is continued, the pulley ratio gradually increases, but before the pulley ratio reaches the second pulley ratio B shown in FIG. 4, the solenoid valve is turned on.
The operation of the low / high control valve 60 due to the OFF operation is prohibited. That is, with the upshift, the movable sheave 7b of the primary pulley 7 is moved to the U / D side, and the sensor shoe 65 is also moved downward in the figure in conjunction with this, but the pulley ratio is the second pulley ratio. Up to B, the base end portion 66a of the interlock rod 66 does not engage with the recessed portion 65a, but contacts the surface of the sensor shoe 65. Therefore, the base end portion 6 of the interlock rod 66 is
The tip portion 66b on the side opposite to 6a is engaged with the recess 60a of the low-high control valve 60, whereby the low-high control valve 60 is mechanically locked while the L mode is maintained and its operation is prohibited.

When the pulley ratio reaches the second pulley ratio B by the upshift, the base end portion 66a of the interlock rod 66 engages with the concave portion 65a of the sensor shoe 65, and the tip end portion 66b on the opposite side is shown in FIG. By moving to the right inside, the engagement of the interlock rod 60 with the recess 60a is released. As a result, when the pulley ratio is equal to or higher than the second pulley ratio B, the low / high control valve 60 can be operated. As will be described later, the low-high control valve 60 is mechanically locked at the second pulley ratio B or less even in the D range-H mode.

Next, the downshift in the D range-L mode is prohibited in the region of the second pulley ratio B or less, and is permitted in the region of the second pulley ratio B or more. That is, in the former region, the ratio sensing valve 63 that moves in conjunction with the movable sheave 7b of the primary pulley 7 via the sensor shoe 65 is in the state shown in the figure, and from the output port v of the primary regulator valve 56. The hydraulic pressure of is stopped by this ratio sensing valve 63, which is necessary for downshifting.
The hydraulic pressure cannot be supplied to the second hydraulic chamber 47. Even in this case, the ratio control valve 5
By connecting the port q of No. 7 to the drain port Ex, the hydraulic pressure of the second hydraulic chamber 49 is controlled so that the low-high control valve 60 has ports k and j, the manual valve 59 has ports d and c, and the ratio control valve 57 has port q. Since it can be drained through, downshifting up to Pri = Sec in FIG. 9 is possible.

On the other hand, in the region where the second pulley ratio is B or more, downshifting can be performed by the ratio sensing valve 63 and the like. That is, above the second pulley ratio B, the movable pulley 7b of the primary pulley 7 moves to the U / D side, and the ratio sensing valve 63 moves downward in the figure via the sensor shoe 65. Therefore, the hydraulic pressure from the primary regulator valve 56 is guided to the downshift relief valve 58 via the check valve 69 as the ports t and u of the ratio sensing valve 63 communicate with each other. Therefore, the downshift relief valve 58 is moved upward in FIG.
And s are communicated with each other, the manual valve 59
It is possible to supply the hydraulic pressure to the second hydraulic chamber 47 through the ports e and f of 1 and the ports 1 and m of the low-high control valve 60. That is, downshift can be performed.

Incidentally, by appropriately setting the second pulley ratio B, in the region where downshift is required,
It is possible to make the downshift work effectively. For example, the second pulley ratio B is set in the vicinity of the first pulley ratio A corresponding to neutral, and the speed ratio of the entire continuously variable transmission is set to 1st (1
If the gear ratio is the same as the (speed), the second pulley ratio B
In, the pulley ratio is fixed and effective engine braking can be applied. (2) D range-H mode The same hydraulic pressure is supplied to the first hydraulic chambers 45 and 46, the high clutch C _H is connected, and further, the hydraulic pressure is supplied to the second hydraulic chamber 49 in the upshift. In the downshift, the hydraulic pressure is supplied to the second hydraulic pressure chamber 47. Below the second pulley ratio B, the operation of the low / high control valve 60 is mechanically prohibited.

That is, in the D range-H mode, as shown in FIG. 7, the manual valve 59 is in the same D range position as in the previous low mode, but the low / high control valve 60 is switched to the H mode position. And ports h and g, j and m, l and k communicate with each other,
And the port i communicates with the drain port Ex.

Therefore, the primary regulator valve 5
The output hydraulic pressure from the output port v of 6 is the ports a and b of the manual valve 59, and the low / high control valve 6
0 is supplied to the high clutch hydraulic servo C _H via ports h and g to engage the clutch C _H , and ports p and q of the ratio control valve 57, ports c and d of the manual valve 59, It is supplied to the second hydraulic chamber 47 of the primary hydraulic servo 32 via the ports j and m of the low-high control valve 60. In this state, the low clutch hydraulic servo C _L is in a released state by communicating with the drain port Ex from the port i of the low / high control valve 60, and the second hydraulic chamber 49 of the secondary hydraulic servo 33 has a low / high control. It communicates with the drain port Ex via the ports k and l of the valve 60, the ports f and e of the manual valve 59, and the port s of the downshift relief valve 58.

As a result, the high clutch C _H is connected, and the CVT 11 is connected to the first and second hydraulic chambers 45 and 4.
Primary side hydraulic servo 32 to which hydraulic pressure is supplied to 7
Is increased by the axial force of the secondary side hydraulic servo 33 that is supplied only to the first hydraulic chamber 46, and in the axial force state corresponding to the torque transmission from the primary pulley 7 to the secondary pulley 9, the ratio is increased. By appropriately adjusting the control valve 57, the hydraulic pressure of the second hydraulic chamber 47 of the primary hydraulic servo 32 is adjusted,
The axial force by the hydraulic servo 32 is adjusted to obtain an appropriate pulley ratio (torque ratio). In this state, the torque transmitted from the engine to the input shaft 3 is appropriately changed by the CVT 11 transmitted from the primary pulley 7 to the secondary pulley 9, and is further extracted from the output shaft 5 via the high clutch C _H.

In the above-mentioned D range-H mode, when the pulley ratio becomes equal to or less than the second pulley ratio B, the operation of the low / high control valve 60 is mechanically prohibited. That is, when the pulley ratio is equal to or greater than the second pulley ratio B,
The movable sheave 7b of the primary pulley 7 is on the U / D side in the figure, and the base end portion 66a of the interlock rod 66 fits into the recessed portion 65a of the sensor shoe 65, while the tip end portion 66b is the recessed portion of the low-high control valve 60. 60b
Since it moves away from the right side in the figure, the low-high control valve 60 can be operated. In contrast,
When the pulley ratio is less than or equal to the second pulley ratio B, the movable sheave 7b of the primary pulley 7 moves to the O / D side, and the base end portion 66a of the interlock rod 66 moves to the sensor shoe 65.
The front end portion 66b on the opposite side is fitted into the concave portion 60b of the low-high control valve 60 by abutting on the surface of the. As a result, the low-high control valve 60 is mechanically locked while the H mode is maintained, and its operation is prohibited.

That is, the low-high control valve 60
Indicates the above-mentioned D range-L mode and the above-mentioned D range-
In any of the H modes, the operation at a pulley ratio equal to or lower than the second pulley ratio B is mechanically prohibited, and the L mode and the H mode are held, respectively. As a result, even when a signal is output to the solenoid valve so as to switch from the D range-H mode to the D range-L mode due to an electrical failure at the time of high rotation of the output shaft 5, the low-high control valve The engine 60 can effectively prevent engine overrev and reverse running without operating.

In the D range-H mode described above, even when the pulley ratio is equal to or less than the second pulley ratio B, downshifting is prohibited unlike the case of the D range-L mode described above. There is no such thing. That is, D range-H
In the mode, in the region below the second pulley ratio B, the hydraulic pressure from the output port v of the primary regulator valve 56 is the ratio sensing valve 63 in the state of FIG.
This hydraulic pressure is not supplied to the second hydraulic chamber 49 via the downshift relief valve 58, the manual valve 59, and the low / high control valve 60. However, instead of this, the hydraulic pressure from the high clutch C _H causes the check valve 69, the ports r and s of the downshift relief valve 58, the ports e and f of the manual valve 59, and the ports 1 and k of the low-high control valve 60. The second hydraulic chamber 49 is supplied via the. As a result, in the D range-H mode, downshifting is possible in the entire area of the pulley ratio. (3) R range In the R range, as shown in FIG.
The first and second hydraulic chambers 4 of the primary side hydraulic servo 32
It is supplied to the first and second hydraulic chambers 46 of the secondary side hydraulic servo 33, and is also supplied to the low clutch hydraulic servo C _L. That is, in the R range, as shown in FIG.
In the range position, the low / high control valve 60 is in the L mode position. In this state,
The manual valve 59 communicates with ports a and b, c and f, and e and d, respectively. Further, the low-high control valve 60 has the ports h, i, and j as in the L mode.
And k, l and m communicate with each other, and the port g communicates with the drain port Ex.

Therefore, the primary regulator valve 5
The hydraulic pressure from the output port v of 6 is the manual valve 59.
Ports a and b, the hydraulic low through the ports h and i of the low-high control valve 60 clutch servo C _L for
To the second hydraulic chamber 47 of the primary hydraulic servo 32 through the ports p and q of the ratio control valve 57, the ports c and f of the manual valve 59, and the ports 1 and m of the low-high control valve 60. . Further, the port s of the downshift relief valve 58 communicates with the drain valve Ex.

As a result, the low clutch C _L is connected, and the CVT 11 is connected to the first and second hydraulic chambers 45 and 4.
The axial force by the primary side hydraulic servo 32 in which the hydraulic pressure acts on 7 becomes higher than that by the secondary side hydraulic chamber 33 by only the first hydraulic chamber 46, and corresponds to torque transmission from the primary pulley 7 to the secondary pulley 9. The hydraulic pressure of the second hydraulic chamber 47 of the primary hydraulic servo 32 is adjusted by adjusting the ratio control valve 57, and the axial force of the hydraulic servo 32 is adjusted to obtain an appropriate pulley ratio. . In this state, CV
When the pulley ratio of T11 is in the predetermined acceleration (O / D) state,
The engine torque from the input shaft 3 is transmitted to the carrier 19c of the planetary gear 19 via the low clutch C _L and the power transmission device 26, and is transmitted from the primary pulley 7 to the secondary pulley 9 via the CVT 11 to transmit the torque to the sun gear 19s. Is transmitted to the output shaft 5 through the ring gear 19r as reverse rotation.

Also in the R range, similarly to the case of the second pulley ratio B or less in the D range-L mode, the supply of hydraulic pressure to the downshift relief valve 58 is prohibited by the sensor shoe 65 and the ratio sensing valve 63. Therefore, downshifting is prohibited. In the R range, originally, engine braking is not particularly required, and therefore no inconvenience occurs even if downshifting is prohibited. (4) N, P range At the P range position and the N range position of the manual valve 59, both the low clutch C _L and the high clutch C _H are released, and the primary side and secondary side hydraulic servos 32, 33 are released. First hydraulic chamber 4
A predetermined hydraulic pressure is supplied to 5, 46. That is, in the manual valve 59, the ports c and d, and e and f communicate with each other, and the port b communicates with the drain port Ex. Further, the low / high control valve 60 is held in the above L range. The port q of the ratio control valve 57 communicates with the drain port Ex, and the ratio sensing valve 63 is held at the position shown in FIG. 7.

Therefore, the primary regulator valve 5
The output hydraulic pressure from the output port v of No. 6 is supplied only to the first hydraulic chamber 45 of the primary hydraulic servo 32 and the first hydraulic chamber 46 of the secondary hydraulic servo 33, and to any valve. There is no. Therefore, the primary hydraulic servo 32 and the secondary hydraulic servo 33 both apply the same hydraulic pressure only to the first hydraulic chambers 45 and 46, and the primary and secondary pulleys 7 and 9 have substantially the same axial force.

In each of the above-mentioned positions D, N, R and L modes and H mode, the first hydraulic chambers 45 and 46 of both the primary and secondary hydraulic servos 32 and 33 are provided.
A predetermined hydraulic pressure is supplied from each of the primary regulator valves 56 to secure a predetermined axial force according to the transmission torque so that the belt does not slip, and the second hydraulic pressure of either one of the hydraulic servos 32 and 33 is secured. Room 4
A pressure control from the ratio control valve 57 acts on 7 or 49 to adjust the ratio of the axial forces of the pulleys 7 and 9 to perform a shift operation so that a predetermined pulley ratio is achieved.

In the above embodiment, the D range-
The boundary pulley ratio for prohibiting downshift in the L mode and the boundary pulley ratio for mechanically prohibiting the operation of the low / high control valve 60 in the D range-L mode and the D range-H mode are both Although the pulley ratio B of 2 is set, these may be set independently. For example, the pulley ratio that prohibits downshift can be set closer to the first pulley ratio, and the pulley ratio that prohibits the operation of the low-high control valve 60 can be set farther from the first pulley ratio. These may be appropriately set according to the actual traveling state of the automobile.

In the above-described embodiment, the sensor shoe 65 that moves in conjunction with the movable sheave 7b on the primary pulley 7 side is used as the detection means for detecting the pulley ratio.
However, instead of this, a sensor shoe that is interlocked with the movable sheave 9b on the secondary pulley 9 side can also be used.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing an embodiment of a power transmission device in a continuously variable transmission according to the present invention.

FIG. 2 is a velocity diagram similarly showing an embodiment of the power transmission device.

FIG. 3 is a diagram showing a change in output torque with respect to a pulley ratio of a belt type continuously variable transmission (CVT).

FIG. 4 is a diagram showing a change in output rotation speed with respect to a CVT pulley ratio.

FIG. 5 is a diagram showing an engagement relationship between a low clutch and a high clutch.

FIG. 6 is a sectional view showing a double-chamber type hydraulic servo which similarly applies an axial force to the primary and secondary pulleys.

FIG. 7 is a hydraulic circuit diagram showing the hydraulic control mechanism.

FIG. 8 is a view showing the structure of a low-high control valve and an interlock rod.

FIG. 9 is a diagram showing the clamping force of the belt by the movable sheave.

[Explanation of symbols]

1 continuously variable transmission 2 engine output shaft (crankshaft) 3 input shaft 5 output shaft 7 first (primary) pulley 7b movable sheave 9 second (secondary) pulley 10 belt 19 planetary gear 19c first rotating element (carrier) ) 19s 2nd rotary element (sun gear) 19r 3rd rotary element (ring gear) 32 1st hydraulic servo 33 2nd hydraulic servo 45,46 1st hydraulic chamber 47,49 2nd hydraulic chamber 57 Ratio control Valve 58 Downshift relief valve 59 Manual valve 60 Low-high switching means (low-high switching valve, low-high control valve) 60a, 60b recess 60c Spool 61 Low clutch relief valve 63 Ratio sensing valve 65 Detection means (position detection member, sensor shoe) 65a Recess 65 , 65c connecting part 66 restricting means (interlock rod) 66a one end (base end portion) 66b and the other end (tip) C _H second clutch (high clutch) C _L first clutch (low clutch)

Claims (5)

[Claims] 1. An input shaft interlocked with an engine output shaft, an output shaft interlocked with wheels, an input shaft-side first pulley, and an input shaft-side first pulley and an output shaft-side first pulley. 2 pulleys and these 1st
And a planetary gear interposed between the input and output shafts, and a torque transmission path between the input and output shafts is changed. As a result, in the continuously variable transmission capable of coping with the low mode having a high torque ratio and the high mode having a low torque ratio, with respect to an arbitrary pulley ratio in the pulley ratio region of the belt type continuously variable transmission, A low / high switching means capable of switching between a high mode and a high mode, a detecting means for detecting a pulley ratio of the belt type continuously variable transmission, and a pulley ratio detected by the detecting means in a predetermined pulley ratio region, A continuously variable transmission, comprising: restriction means for restricting the operation of the low / high switching means to prohibit switching between the low mode and the high mode. 2. A first clutch having a first hydraulic servo, which is engaged by supplying hydraulic pressure to the first hydraulic servo to achieve the low mode, and a second hydraulic servo. And a second clutch that is engaged by supplying hydraulic pressure to the second hydraulic servo to achieve the high mode, wherein the low / high switching means includes the first and second hydraulic pressures. The continuously variable transmission according to claim 1, further comprising a low / high switching valve that switches the supply of hydraulic pressure to the servo. 3. The low-high switching valve includes a spool that switches a hydraulic pressure supply path to the first and second hydraulic servos based on an output signal from the detection means, and the restriction means includes the pulley. The continuously variable transmission according to claim 2, further comprising a lock member that locks the one spool when the ratio is within the predetermined pulley ratio region. 4. The first and second pulleys each have a movable sheave that changes the pinching pressure on the belt to change the pulley ratio, and the detection means has one end of the lock member engaged. It has a position detecting member that moves in conjunction with one of the movable sheaves and has a concave-convex portion that is removed, and the lock member has the other end that is engaged and disengaged with the concave-convex portion. The continuously variable transmission according to claim 3, wherein the spool locks or unlocks the spool. 5. The planetary gear includes a first rotating element connected to the input shaft, a second rotating element connected to the second pulley, and a third rotating element connected to the output shaft. An element, the first clutch connects the input shaft and the first rotating element, and the second clutch includes one of the first, second, and third rotating elements. Any one of two rotating elements is connected, Any one of Claim 2 thru | or 4 characterized by the above-mentioned.
The continuously variable transmission according to the item.