JPH0280845A - Belt type continuously variable transmission for vehicle - Google Patents

Abstract

PURPOSE:To prevent the abrasion of a planetary gear and a belt and the occurrence of seizure of the planetary gear by providing a closing valve which closes a connecting oil passage in a condition of feeding operating oil under pressure by means of a hydraulic pump and which opens the connecting oil passage in a condition of feeding no operating oil under pressure by means of the hydraulic pump. CONSTITUTION:In a hauled condition in which no operating oil is fed under pressure by means of a hydraulic pump, a centrifugal oil pressure is generated in a primary side oil pressure cylinder 30 accompanying the relatively high-speed rotation of an input shaft 26, the this oil pressure and a centrifugal oil pressure in a secondary side oil pressure cylinder tend to be balanced at a certain change gear ratio. At this time, since a connecting oil passage 84 which connects the inside of the cylinder 30 and an oil intake port 82 is opened by means of a closing valve 90, operating oil stored in a housing 25 is taken in from the oil intake port 82 and flows into the cylinder 30, increasing the centrifugal oil pressure in the cylinder 30. Thereby, the effective diameter of a primary side variable pulley 34 is gradually increased to lower the rotating speed of an input shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a belt-type continuously variable transmission for a vehicle.

Conventional technology A housing, an input shaft and an output shaft rotatably supported within the housing, and a pair of primary variable pulleys each provided with an outer circumferential groove having a variable groove width and provided on the input shaft and the output shaft, respectively. and a secondary side variable pulley, a primary side hydraulic cylinder and a secondary side hydraulic cylinder that change the outer peripheral groove width of the pair of primary side variable pulley and secondary side variable pulley, and said primary side variable pulley and secondary side variable It is equipped with a transmission belt wrapped around the outer peripheral groove of the pulley, and the gear ratio is changed by adjusting the pressure or flow rate of hydraulic oil supplied from the hydraulic pump to the primary hydraulic cylinder and secondary hydraulic cylinder. A belt-type continuously variable transmission for a vehicle is known. Such a belt-type continuously variable transmission may be provided downstream of a forward/reverse switching device for switching the rotational direction of the engine. For example, the belt type continuously variable transmission described in Japanese Patent Application Laid-Open No. 61-31752 is one such example.

Problems to be Solved by the Invention However, in a vehicle in which a belt-type continuously variable transmission is provided after the forward/reverse switching device as described above, when the vehicle is being towed, the forward/reverse switching device is in a neutral state ( The variable pulley of the belt type continuously variable transmission is rotated along with the rotation of the drive wheels. Normally, in a belt-type continuously variable transmission, the gear ratio is changed to the maximum deceleration side by quantity deceleration control before the vehicle stops, and the gear ratio is set to the maximum value. Then, the variable boob on the input side is rotated at a relatively high speed. For this reason, in towed vehicles where the hydraulic pump is not driven and lubricating oil is not forcibly supplied, there is a risk that the planetary gears and transmission belts that make up the forward/reverse switching device will wear out and their durability may be impaired. . Furthermore, if the vehicle continues to be towed for a long period of time, the planetary gear may seize.

The present invention has been made against the background of the above circumstances,
The purpose is to provide a belt-type continuously variable transmission that suppresses wear of the planetary gears and belts constituting the forward/reverse switching device and prevents burnout of the planetary gears even when the vehicle is towed. There is a particular thing.

Means for Solving the Problems The gist of the present invention is to provide an input shaft and an output shaft rotatably supported within a housing, and an outer circumferential groove having a variable groove width. A pair of primary variable pulleys and a secondary variable pulley provided on the input shaft and the output shaft, respectively, and a primary hydraulic cylinder that changes the outer circumferential groove width of the pair of primary variable pulleys and secondary variable pulleys; It is equipped with a secondary hydraulic cylinder and a transmission belt wrapped around the outer circumferential grooves of the primary variable pulley and the secondary variable pulley, respectively, and supplies each from the hydraulic pump to the primary hydraulic cylinder and the secondary hydraulic cylinder. A held-type continuously variable transmission for a vehicle in which the gear ratio is changed by adjusting the pressure or flow rate of hydraulic fluid, which (a) opens into the housing and stores in the housing; (b) a connecting oil passage connecting the inside of the primary side hydraulic cylinder and the oil spraying day; (C) when the hydraulic oil is being pumped by the hydraulic pump; The apparatus further includes an on-off valve that closes the connecting oil passage, but opens the connecting oil passage when hydraulic oil is not being pumped by the hydraulic pump.

Operation and Effect of the Invention With this arrangement, in a towed state where hydraulic oil is not pumped by the hydraulic pump, centrifugal hydraulic pressure is generated in the primary hydraulic cylinder as the input shaft is rotated at a relatively high speed. This centrifugal oil pressure and the centrifugal oil pressure in the secondary hydraulic cylinder are tried to be balanced at a certain gear ratio. At this time, the connecting oil passage connecting the inside of the primary hydraulic cylinder and the oil intake port is opened by the on-off valve, so the hydraulic oil stored in the housing is taken in from the day of oil spraying and flows into the primary hydraulic cylinder. Then, the centrifugal oil pressure in the primary hydraulic cylinder increases. As a result, the effective diameter of the primary variable pulley is gradually increased and the input shaft rotational speed is lowered, reducing wear on the transmission belt and the planetary gear of the forward/reverse switching device, and improving durability. Furthermore, seizure of the planetary gear of the forward/reverse switching device that rotates together with the input shaft is also suppressed.

Here, the on-off valve is preferably inserted into the connecting oil passage, and closes the passage when the oil pressure in the primary hydraulic cylinder is higher than that in the housing, and closes the passage in the primary hydraulic cylinder. A check valve opens the connecting oil passage when the oil pressure in the housing becomes equal to the pressure in the housing.

Further, the on-off valve preferably includes a spool valve element that opens and closes the connecting oil passage, and a spring that biases the spool valve element toward the valve-opening position. It is constituted by a spool valve that closes the connecting oil passage when hydraulic pressure is applied to the spool valve element, but opens the connecting oil passage when the hydraulic pressure is not applied.

Further, the oil intake port is preferably opened at a position above an oil passage provided in the input shaft and communicating with the primary hydraulic cylinder.

Further, the oil intake port is preferably opened at a position facing the variable pulley.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In the vehicle power transmission device shown in FIG.
The power of
, intermediate gear device 16, and differential gear device 18 to drive wheels 20.

The fluid coupling 12 includes a pump impeller 24 connected to the crankshaft 22 of the engine 10 and a turbine impeller 2 connected to the input shaft 41 of the forward/reverse switching device 13.
8 and a lock-up clutch 29 that directly connects the pump impeller 24 and the turbine impeller 28, and when the vehicle is started, the engine 10 is connected to the forward/reverse switching device 13 and the belt-type continuously variable transmission. The torque transmitted to the pump impeller 24 is increased smoothly, or when the vehicle is stopped, the rotation of the engine 10 is allowed regardless of the rotation of the drive wheels 20 being stopped. Turbine impeller 2
8 to prevent rotation loss.

The forward/reverse switching device 13 is a Ravigneaux type compound planetary gear mechanism connected to the output shaft side of the fluid coupling 12, and includes a first Zang gear 42, a second sun gear 43, and a first planetary gear that meshes with the first sun gear 42. 44, and a second planet gear meshing with the first planetary gear 44 and the second sun gear 43.
It includes a planetary gear 45, a ring gear 46 that meshes with the first planetary gear 44, and a carrier 47 that rotatably supports the first planetary gear 44 and the second planetary gear 45.

The second sun gear 43 is connected to the turbine impeller 28 which is the output member of the fluid coupling 12, and the carrier 47 is connected to the input shaft 26 of the belt type continuously variable transmission 14. The first sun gear 42 and the second sun gear 43
The first sun gear 42 and the housing 25, which is a non-rotating member, are selectively engaged by the low speed brake 49. A reverse brake 50 selectively engages the housing 25, which is a non-rotating member. Therefore, as shown in FIG. 2, the high gear is selected by the operation of the high speed clutch 48, the low gear is selected by the operation of the low speed brake 49, and the reverse gear is selected by the operation of the reverse brake 50. The high-speed clutch 4B, the low-speed brake 49, and the reverse brake 50 are all deactivated, resulting in a neutral state (non-transmission state).

Note that in FIG. 2, ◯ indicates an engaged state, and × indicates a non-engaged state. Further, when the number of teeth of the first sun gear 42 is 251, the number of teeth of the second sun gear 43 is ZS□, and the number of teeth of the ring gear 46 is Zr, ρ.

and ρ2 are defined from the following equation.

ρ, = zst/zr ρ2−ZS□/Z.

The heald type continuously variable transmission 14 includes an input shaft 26 and an output shaft 36 that are rotatably supported within a housing 25 and are parallel to each other. The input shaft 26 is provided with a primary variable pulley 34 whose groove width, that is, the engagement diameter of the transmission heald 32 is changed by the primary hydraulic cylinder 30, and the output shaft 36 is provided with a secondary hydraulic cylinder. Secondary variable pulley 40 whose groove width is changed by 38
is provided. Therefore, the primary hydraulic cylinder 3
When the thrust force generated by The gear ratio (=input shaft rotational speed N, w/output shaft rotational speed N.ut) of the continuously variable transmission 14 is reduced. On the other hand, when the thrust by the primary hydraulic cylinder 30 is made relatively smaller than the thrust by the secondary hydraulic cylinder 38, the effective diameter of the primary variable pulley 34 is reduced and at the same time the secondary variable pulley 40 is reduced. The effective diameter is increased,
The gear ratio of the continuously variable transmission 14 is increased.

The gear 52 provided on the output shaft 36 of the belt type continuously variable transmission 14 is meshed with the intermediate gear device 16, and the intermediate gear device 16 is meshed with the differential gear device 18. Continuously variable transmission 1 at a constant reduction ratio determined by the structure of differential gear 18
4 output torque is transmitted to the drive wheels 20.

A manual valve (not shown) in the hydraulic circuit 58 is mechanically connected to a shift lever (not shown), and when the shift lever is operated to the neutral range,
Although hydraulic pressure is prevented from being supplied from the hydraulic circuit 58 to any of the high speed clutch 48, low speed brake 49, and reverse brake 50 of the forward/reverse switching device 13,
When the shift lever is operated to the reverse range, hydraulic oil is supplied only to the reverse brake 50 through the hydraulic circuit 58. Further, when the shift lever is operated to the forward range, hydraulic fluid is selectively supplied to either of the high speed clutch 48 and the low speed brake 49 from the hydraulic circuit 58. This selection is made by a controller (not shown) based on the running state of the vehicle, such as vehicle speed or throttle valve opening θ.

The hydraulic circuit 58 also uses a line hydraulic pressure regulated in accordance with the actual gear ratio of the belt-type continuously variable transmission 14 and the output torque of the engine 1o in accordance with a command signal from a controller (not shown) through an oil path 60 to a secondary source. Side hydraulic cylinder 3
8 to control the tension of the transmission belt 32 as necessary and sufficient. In addition, the hydraulic circuit 5 supplies hydraulic oil to the primary hydraulic cylinder 30 through the oil passage 62 provided in the input shaft 26 or discharges it from the primary hydraulic cylinder 30 in accordance with a command signal from a controller (not shown). For example, the gear ratio of the belt type continuously variable transmission 14 is adjusted so that the engine 10 operates along the minimum fuel efficiency curve. The hydraulic pump 64 is constantly driven to rotate by the engine 10 or the like, and pressure-feeds the hydraulic oil returned from the return oil passage 66 and the hydraulic oil returned to the oil tank 68 to the hydraulic circuit 58.

In this embodiment, as shown in detail in FIGS. 3 and 4, the primary side variable pulley 34 includes a fixed rotating body 34a fixed to the input shaft 26, and a fixed rotating body 34a that is movable in the axial direction with respect to the input shaft 26. A movable rotating body 34 that is non-rotatable around the axis.
A cylinder plate 37 fixed to the input shaft 26 is slidably fitted into a cylindrical portion 35 protruding from the back surface of the movable rotating body 34b, thereby forming the primary hydraulic cylinder 30. is configured.

The input shaft 26 rotatably supported by a bearing 70 also has a hole 7 that communicates with the primary hydraulic cylinder 30.
2 is formed, and this hole 72 is the end plate 74.
The oil passage 62 is formed to connect the primary side hydraulic cylinder 30 and the hydraulic circuit 58 by being oil-tightly fitted with an annular projection 76 formed in the oil passage 62 . End plate 74
is fixed by a bolt 78 in close contact with the end face of the housing 25, and is connected to the oil passage 62 and the inside of the housing 25 through a hole 80 formed in the end plate 74 and an oil intake port 82 formed in the housing 25. A connecting oil passage 84 is formed to communicate with the two. A check valve 90 is inserted into this connecting oil passage 84 with a spherical valve element 86 housed in a valve chamber 88 formed between the end surface of the housing 25 and the end plate 74. . The oil intake port 82 is opened opposite to the inner wall surface of an oil receiving groove 92 which is formed upwardly at a position above the input shaft 26 on the inner wall surface of the housing 25, The oil received by the groove 92 can be efficiently taken into the oil intake port 82.

That is, the oil intake port 82 is opened above the input shaft 26 so as to be located substantially on a vertical line passing through the axis of the input shaft 26.

Next, the effects of the above embodiment will be explained.

When the hydraulic pump 64 is rotationally driven by the rotation of the engine 10, the hydraulic oil that is pressure-fed from the hydraulic pump 64 and regulated to a predetermined pressure is supplied to the primary side hydraulic cylinder 30.
The spherical valve element 86 is seated due to the pressure difference between the inside of the connecting oil passage 84, which has the same pressure as the primary side hydraulic cylinder 30, and the inside of the housing 25, which has approximately atmospheric pressure, and the check valve 90 is closed, the gear ratio control is executed without any problem regardless of the existence of the connecting oil passage 84.

When the rotation of the engine 10 is stopped, hydraulic oil is not pumped from the hydraulic pump 64, so the inside of the primary hydraulic cylinder 30 is at approximately atmospheric pressure, and the inside of the primary hydraulic cylinder 30 and the inside of the housing 25 are at the same pressure. Become a spherical valve 8
6 is separated from the seating surface by gravity, and the check valve 90 is opened. In addition, in this state, hydraulic oil is not pumped from the hydraulic pump 64, so the high-speed clutch 48, the low-speed brake 49, and the reverse brake 50 are all inactive, and the forward/reverse switching device 13 stops power transmission. It becomes a neutral state where it is cut off.

In this way, the engine 10 is stopped and the forward/reverse switching device 1
When the vehicle is towed with the wheel 3 in the neutral state, rotational force is transmitted from the drive wheels 20 to the heald type continuously variable transmission 14. In the belt type continuously variable transmission 14, as the vehicle speed decreases and the throttle valve opening is fully closed, the speed ratio control changes the gear ratio toward the maximum speed reduction side, that is, the maximum speed ratio side. Therefore, the effective diameter of the primary variable pulley 34 of the belt-type continuously variable transmission 14 is made small, and the effective diameter of the secondary variable pulley 40 is made large. When the vehicle is towed as described above under the condition where the hydraulic pump 64 is not rotationally driven and lubricating oil is not forcibly supplied, the primary variable pulley 34 is rotated at a relatively high speed. There was a risk that the planetary gears 44, 45 and the transmission belt 32 in the forward/reverse switching device 13 would wear out, resulting in loss of durability. In addition, if the above-mentioned towed state continues for a long time, the planetary gear 4
In some cases, burn-in of 4.45 occurred. Note that even in the conventional case, centrifugal oil pressure is generated in the primary variable pulley 34, but since the amount of hydraulic oil in the primary variable pulley 34 is small, the centrifugal oil pressure is small and the change in the gear ratio is only small. I couldn't get it.

However, in this embodiment, as the vehicle is towed under the condition where the hydraulic pump 64 is not driven to rotate and lubricating oil is not forcibly supplied as described above, the primary variable pulley 34 is rotated at a relatively high speed. When the oil is about to be removed, the oil stirred by the primary variable pulley enters the oil receiving groove 9.
The hydraulic oil in the housing 25 flows into the primary side hydraulic cylinder 30 through the reservoir oil intake port 82 and the connecting oil passage 84 opened by the check valve 90 . That is, as shown in FIG. 5, inside the housing 25,
The hydraulic oil drained in the hydraulic circuit (not shown) is stored for re-pressure feeding, and a part of the primary variable pulley 34 is immersed in the stored hydraulic oil, so that the primary variable pulley 34 is immersed in the stored hydraulic oil. 34 is rotated at a relatively high speed, the hydraulic oil is agitated and received by the oil receiving groove 92. Therefore, this oil receiving groove 9
The hydraulic oil received in the hydraulic cylinder 2 flows into the oil intake port 82 and is supplied into the primary hydraulic cylinder 30.

As described above, when the hydraulic oil in the housing 25 flows into the primary hydraulic cylinder 30, the centrifugal oil pressure in the secondary hydraulic cylinder 30 is further increased, and the groove width of the primary variable pulley 34 is reduced. The effective diameter is being expanded. FIG. 6 shows the above process using solid lines in contrast to the broken lines showing the conventional case.

As described above, according to this embodiment, when the vehicle is being towed, the hydraulic oil in the housing 25 is caused to flow into the primary variable pulley 34 through the connection oil passage 84, so that the belt type continuously variable transmission 14 is made smaller, the rotational speed of the primary variable pulley 34 is lowered, and the transmission heald 32 and the planetary gear 44.4 of the forward/reverse switching device 13 are lowered.
5 is reduced and durability is improved, and at the same time, seizure of the planetary gears 44 and 45 of the forward/reverse switching device 13 is also suppressed.

Further, according to this embodiment, since the oil intake port 82 is opened in the oil receiving groove 92, the hydraulic oil that is stirred or scattered by the primary variable pulley 34 in the housing 25 can be easily transferred to the primary side. It has the advantage of being incorporated into the variable pulley 34.

Next, another embodiment of the present invention will be described. In the following description, the same parts as in the above-mentioned embodiments are given the same reference numerals, and the description thereof will be omitted.

A spool valve 100 shown in FIG. 7 can be used in place of the check valve 90 to open and close the connecting oil passage 84. The spool valve 100 includes, for example, a spool valve element 104 that is slidably fitted into a cylinder pore 102 formed in an end plate 74 and is alternatively positioned between an open position and a closed position.
and a spring 106 that constantly biases the spool valve element 104 toward the open position. An oil passage 108 is provided at one end of the spool valve element 104 to allow the hydraulic oil pumped by the hydraulic pump 64 to act at all times. 106 to the closed position, the connection oil passage 84 is closed, and the primary side hydraulic cylinder 30 and a hydraulic circuit (not shown) are connected via the oil passage 62. However, engine 10
When the hydraulic pump 64 is no longer rotationally driven due to the stoppage of the hydraulic pump 64, the spool valve element 104 is moved to the open position according to the biasing force of the spring 106, so that the next hydraulic cylinder 3
0 and the oil passage 62, the connecting oil passage 84 is opened at the same time, and the oil intake port 8 opens into the housing 25.
2 and the primary hydraulic cylinder 30 are communicated with each other.

FIG. 7 shows this state, and the hydraulic oil in the housing 25 is caused to flow into the primary hydraulic cylinder 30 according to the broken line. In this way, also in this embodiment, the hydraulic oil in the housing 25 is taken into the primary side hydraulic cylinder 30 through the connection oil passage 84 when the rotation of the hydraulic pump 64 is stopped. A similar effect can be obtained.

Although one embodiment of the present invention has been described above based on the drawings,
The invention also applies in other aspects.

For example, in the embodiment described above, the oil inlet 82 is connected to the input shaft 2.
Although the opening is above the input shaft 26 at a position on a vertical line passing through its axis, the opening may be opened at a position diagonally above the input shaft 26. Furthermore, even if the oil intake port 82 is opened below the axis of the input shaft 26, if the upper end 96 of the oil receiving groove 92 is above the horizontal plane 95 shown in FIGS. , a certain effect can be obtained.

In addition, in the above embodiment, in order to reduce the gear ratio of the heald type continuously variable transmission 14 when towing the vehicle, the movable rotating body 34b of the primary variable pulley 34 or the movable rotating body of the secondary variable pulley 40 is It is also possible to provide a spring that biases the gear ratio in the direction of decreasing.

Further, in the forward/reverse switching device 13 of the above-described embodiment, the forward/reverse
Although several gear stages were provided, it could also be one forward gear.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a vehicle power transmission device including an embodiment of the present invention. FIG. 2 is a chart showing the operating state of the forward/reverse switching device shown in FIG. 1. FIG. 3 is a sectional view of a main part of the embodiment shown in FIG. 1. FIG. 4 is a front view of the end plate of FIG. 3. FIG. 5 is a partially cutaway view of the housing of the embodiment of FIG. 1. FIG. 6 is a time chart illustrating the operation of the embodiment shown in FIG. FIG. 7 is a diagram showing essential parts of another embodiment of the present invention. 14: Belt type continuously variable transmission 25: Housing 26: Input shaft 30 Primary side hydraulic cylinder 32: Transmission heald 34 Primary side variable pulley 36: Output shaft 38: Secondary side hydraulic cylinder 40: Secondary side variable pulley 64 : Hydraulic pump 82: Oil spraying day 84: Connection oil path 90: Check valve (on-off valve) 100 Nispool valve (on-off valve) Applicant: Toyota Motor Corporation

Claims (1)

[Claims] A housing, an input shaft and an output shaft rotatably supported within the housing, and a pair of primary shafts each provided with an outer circumferential groove having a variable groove width and provided on the input shaft and the output shaft, respectively. A side variable pulley and a secondary side variable pulley, a primary side hydraulic cylinder and a secondary side hydraulic cylinder that change the outer peripheral groove width of the pair of the primary side variable pulley and the secondary side variable pulley, and the primary side variable pulley and the secondary side variable pulley. A transmission belt is wound around the outer circumferential groove of the next variable pulley, and the pressure or flow rate of the hydraulic oil supplied from the hydraulic pump to the primary hydraulic cylinder and the secondary hydraulic cylinder is adjusted. A belt-type continuously variable transmission for a vehicle in which the gear ratio can be changed, the oil inlet opening opening into the housing to take in hydraulic oil stored in the housing, and an oil inlet opening in the primary side hydraulic cylinder. and a connecting oil passage connecting the oil inlet and the oil intake port; the connecting oil passage is closed when the hydraulic oil is being pumped by the hydraulic pump, but the connecting oil passage is closed when the hydraulic oil is not being pumped by the hydraulic pump. A belt-type continuously variable transmission for a vehicle, comprising: an on-off valve that opens and closes;