JPS6362950A - Belt-type continuously variable transmission - Google Patents

Abstract

PURPOSE:To carry out correction of misalignment between pulleys during running in a belt-type continuously variable transmission, by providing a balancing spring for balancing a cylinder pressure against a line pressure to axially move an input pulley. CONSTITUTION:Fixed sheaves 7a and 8a are integrally formed with an input shaft 1 and an output shaft 2, respectively, and movable sheaves 7b and 8b are supported to the fixed sheaves 7a and 8a by spline engagement, respectively. Piston cylinders 9 and 10 are mounted on the back surfaces of the movable sheaves 7b and 8b, respectively, and are liquid-tightly and slidably engaged with cylinders 11 and 12, respectively, thus defining pressure chambers 13 and 14 between the respective piston cylinders and the respective cylinders. A balancing spring 15 is provided in the pressure chamber 14 on the output shaft 2 side. An endless belt 16 is wrapped around a drive pulley 7 and a driven pulley 8. A line pressure is induced from an oil passage 20 into a pressure chamber 18. A balancing spring 19 is provided to balance the pressure in the pressure chamber 13 against the line pressure in the pressure chamber 18.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a belt-type continuously variable transmission in which alignment between pulleys can be adjusted during operation.

[Conventional technology]

Usually, in this type of belt-type continuously variable transmission, the belt is wound between each pulley of the input and output shafts, which have pulleys that sandwich the belt between sheaves with tapered surfaces. It has a similar structure. In this case, when one sheave is expanded or contracted, the other sheave is expanded or expanded, changing the gear ratio, but the input shaft pulley and output shaft pulley of the movable sheave are opposite to each other. Even if the misalignment between the pulleys is set to zero at a given gear ratio, due to the gear shifting operation, at other gear ratios,
Misalignment occurs while driving. Therefore, as in the continuously variable transmission disclosed in JP-A No. 56-80551, the pulleys on at least one of the input and output shafts are structured so that both sheaves can move together, and the same hydraulic pressure is applied to both sheaves. Therefore, a method of controlling the gear ratio has been proposed. However, in this case, a slight biased pressure applied to the belt causes the sheave to shift to the left or right, resulting in a loss of stability and making the overall structure complex. Therefore, like the continuously variable transmission described in Japanese Patent Application Laid-open No. 60-65946, a conventional pulley with only one side sheave is movable is used, and the alignment is adjusted at the midpoint of the used gear ratio. Efforts have been made to keep the misalignment (hereinafter referred to as misalignment) within a relatively small range. [Problems to be Solved by the Invention] In this case, the relative misalignment in the shift range used is at most half, and cannot be corrected beyond that, which is still insufficient. The present invention has been made based on the above-mentioned circumstances, and it is an object of the present invention to provide a continuously variable transmission that can realize stable operating conditions and sufficient misalignment correction during operation with only slight structural improvements. It is something to do.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a pulley on the input/output shaft that is composed of a fixed sheave and a movable sheave each having a tapered surface, and the movable sheave is operated by hydraulic pressure, a piston that moves in the axial direction together with the pulley is provided on one side of the input/output shaft, and the hydraulic pressure is applied to one side of the piston,
A balance spring facing the hydraulic pressure is disposed on the other side of the piston. [Function] Therefore, for speed ratio control, when the pressure (line pressure) acting on the movable sheave acts on the piston, the entire pulley on the input shaft side moves, making it possible to adjust misalignment with the output pulley. Become. [Embodiment 1] Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In the figure, reference numeral 1 indicates the input shaft of the continuously variable transmission;
is an output shaft, and the input shaft 1 is rotatably supported in the rotational direction with respect to the housing 5.6 by a needle bearing 3° and a ball bearing 4, in which the inner race also serves as the shaft. Above input shaft 1 and output shaft 2
The pulleys 7.8 respectively provided in the fixed sheaves 7a, 8a have conical tapered surfaces on opposing surfaces.
and movable sheaves 7b, 8b are installed on the left and right sides of the pulley 7.8 in opposite directions. The fixed sheave 7a, 8a has an input @1. A movable sheave 7b, which is formed integrally with the output shaft 2, respectively.
8b is the input shaft 1. It is supported so as to be movable in the axial direction with respect to the output shaft 2 and locked in the rotational direction, for example, by spline fitting. There are piston cylinders 9 and 10 on the back surfaces of the movable sheaves 7b and 8b, which are connected to the input shaft 1. It is fluid-tightly and slidably fitted into a cylinder 11.12 provided on the output shaft 2, and defines a pressure chamber 13.14 inside. Note that on the output shaft 2 side, a balance spring 15 is provided within the pressure chamber 14 . An endless belt 16 is connected between the drive side pulley 7 and the driven side pulley 8.
is equipped with winding. In particular, in the present invention, the bearing 4 that supports the input shaft 1 is supported by the housing 6 via the piston 17, and the piston 17 is movable in the axial direction within a pressure chamber 18 provided in the housing 6. fitted, the piston 17
When the input shaft 1 moves together with the movement of the drive side pulley 7, the drive side pulley 7 is also moved. Line pressure on the discharge side of the oil pump (not shown) is introduced into the pressure chamber 18 from the oil passage 20 after being adjusted by an output side valve (not shown). And the piston 17 on the opposite side to the pressure chamber 18
A balance spring 19 provided between the housing 6 and the
The line pressure in the pressure chamber 18 is counterbalanced. In such a configuration, the driving diameter of pulley 7 and the driven diameter of pulley 8 are determined by the balance of pressure supply to each pressure chamber 13, 14, and it is known that the required gear ratio can be automatically adjusted during operation. be. Now, when the groove centers of pulley 7 and pulley 8 are set at the time of the minimum gear ratio (misalignment is zero), and the time when pulley 8 moves to the right in FIG. 1 relative to pulley 7 is taken as negative. Misalignment changes as shown in the curve in FIG. 2 with respect to the gear ratio. On the other hand, the relationship between the line pressure and the gear ratio changes as shown in FIG. Therefore, when line pressure is applied to the pressure chamber 18, the pulley 7 balances with the spring 19 and moves along with the input shaft 1 as the piston 17 moves.
It moves to the right, the apparent upward movement, and the misalignment m moves in the positive direction (.If the shift continues as it is, the misalignment m moves in the positive direction (Fig. 2), but as it does so, the line pressure increases. decreases, the piston 17 balances the spring 19 and the pressure oil in the pressure chamber 18, and the boo 97 moves to the left, and the apparent misalignment amount above moves to the negative side.Then, the gear ratio changes. When the line pressure further decreases, the piston 17 comes into contact with the wall surface 6a of the housing 6.Then, the movement m of the piston 17, that is, the movement amount of the pulley 7 becomes curve C in FIG. Misalignment can be adjusted by combining the misalignment characteristics shown in the figure with the amount of movement of pulley 7.Here, misalignment can cause wear and tear on the belt 16 wound around pulley 7.8. This occurs when the speed of the belt 16 is at its maximum, that is, when the gear ratio is at its minimum. Therefore, if the misalignment caused by both pulleys 7.8 is zero when the gear ratio is at its minimum, there will be no problem with the belt 16. For the reasons mentioned above, the misalignment characteristics caused by both pulleys 7 and 8 shown in Fig. 2 are initially set so that they are on the positive side at the minimum gear ratio, as shown in A of Fig. 4. As a result, when the misalignment A when the piston 17 is not moved and the shift C when the piston 17 is moved, as shown in B in Fig. 4, the actual amount of misalignment between the pulleys reaches a certain limit. Figure 5 shows a second embodiment of the present invention. That is, a hydraulic valve operated by a pulley ratio sensor that detects the gear ratio is provided, and the pressure The oil pressure applied to the seedlings 18 is turned on and off when the pulley ratio is above or below a certain pulley ratio, and the alignment of the belt is changed, for example, into two stages. At the same time, a pulley ratio sensor 21 is provided that follows the axial displacement of the movable sheave. An adjustment bolt 22 is provided for adjusting the head 25 of the spool 24 in the hydraulic valve 23 when the arm 21a at the other end of the pulley ratio sensor 21 is at a predetermined gear ratio.
It is provided so as to press the A spool 24 is fitted into the cylinder 23a of the hydraulic valve 23 and is held in the position shown in the figure by a spring 26 in a free state. An inlet port 27 on which line pressure, lubricating oil pressure, etc. act, an outlet boat 28 communicating with the oil passage 20, and a drain port 29 are open in the cylinder 23a. When the spool 24 is pressed downward by the spring 2G, the inlet port 27 and the outlet boat 28 communicate with each other, and the arm 21a moves to close the head 25 of the spool 24.
When pressed against the spring 26, the inlet boat 27 is shut off and the outlet boat 28 is communicated with the two drain ports. The operation of the second embodiment configured in this way will be described. When the gear ratio is large, the pulley ratio sensor 21 is in the position shown in the figure, so the hydraulic valve 23 guides lubricating oil from the inlet boat 27 to the outlet boat 28 and applies hydraulic pressure to the pressure chamber 18. Therefore, the pulley 7 moves rightward, and as shown by arrow a in FIG. 6, the apparent upward movement and the misalignment amount move in the positive direction. When the gear ratio changes from large to small, the movable sheave 7b
is displaced in the right direction, so the arm 21a moves toward the spool 2.
Push the head 25 of No. 4 upward against the spring 2G. As a result, the pressure oil in the pressure chamber 18 drains from the drain port 29, so the fixed sheave 7a moves in the opposite direction due to the action of the spring 19, and the misalignment moves in the negative direction as shown by the arrow in FIG. . In other words, as shown in D in Figure 6, the misalignment is 9.
When the pulley 7 is on the positive side, the pulley 7 is moved to the positive side by a predetermined amount, and when it becomes positive, the pulley 7 is moved to the negative side by a predetermined amount. By doing so, the apparent misalignment is reduced, so the pressure can be precisely regulated by the pulley ratio. Misalignment can be corrected to within the limit value by supplying low-level hydraulic pressure and changing only the drain in two steps without using additional hydraulic pressure. The same effect as described above can be obtained even if it is provided on the pulley 8 side. [Effects of the Invention] As described in detail above, the present invention allows the axial movement of the pulley on the input shaft side to be balanced by 1q with the balance between the line pressure and the balance spring, so that the pulley position can be stabilized. However, it is possible to sufficiently adjust misalignment, and effects such as the elimination of AT vibrations on the belt can be obtained.

[Brief explanation of drawings]

Fig. 1 is a longitudinal side view showing an embodiment of the present invention, Fig. 2 is a diagram showing misalignment 5, Fig. 3 is a diagram showing the relationship between line pressure and gear ratio, and Fig. 4 is a diagram showing misalignment 5. A diagram showing the correction, FIG. 5 is a diagram showing the second embodiment, and FIG. 6 is a diagram showing the second embodiment.
It is a figure showing correction of misalignment of an example. 1... Input shaft, 2... Output shaft, 3.4... Bearing, 5.6... Housing, 6a... Wall, 7.8
...Pulley, 7a, 8a-...Fixed sheave, 7b,
81)--Movable sheave, 9°10... Piston tube, 11.12... Cylinder, 13.14... Pressure chamber, 15... Balance spring, 16... Belt, 17
... Piston, 18 ... Pressure chamber, 19 ... Balance spring, 20 ... Oil passage. Patent applicant: Fuji Heavy Industries Co., Ltd. Agent, Patent attorney: Makoto Kobashi, Patent attorney: Shinji Murai

Claims (1)

[Claims] A pulley comprising a fixed sheave and a movable sheave each having a tapered surface is provided on the input and output shafts, and the movable sheave is operated by hydraulic pressure, wherein at least one of the input and output shafts On one side, a piston is provided that moves in the axial direction together with the pulley, and by applying the hydraulic pressure to one side of the piston, the misalignment that occurs between the input and output pulleys is reduced. Belt type continuously variable transmission.