Continuously variable transmission

Abstract

To reduce abrasion during high load operation.SOLUTION: A continuously variable transmission includes a primary pully which includes a shaft, a fixed sheave fixed to the shaft, a movable sheave movable on the shaft along an axis line of the shaft, a lubricating oil flow passage formed inside the shaft, and a first oil hole opened to an outer surface of the shaft and fluidly communicating with the lubricating oil flow passage. The first oil hole is opened to the outer surface of the shaft at a position facing a cone surface of the movable sheave at under-drive.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a continuously variable transmission. [Background technology]

[0002] A vehicle may be equipped with a continuously variable transmission (CVT). Lubricating oil is supplied to the continuously variable transmission for lubrication and cooling. For example, Patent Document 1 discloses a continuously variable transmission that includes a primary pulley, a secondary pulley, a chain wound around the primary pulley and the secondary pulley, a chain guide, and a chain guide support member. In this continuously variable transmission, lubricating oil is injected toward the primary pulley and the secondary pulley from an injection hole formed in the chain guide support member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-19889 A Summary of the Invention [Problem to be solved by the invention]

[0004] During high load operation, the chain wrap diameter is smaller at the primary pulley, so the continuously variable transmission experiences greater wear at the primary pulley during high load operation.

[0005] An object of the present invention is to provide a continuously variable transmission capable of reducing wear during high load operation. [Means for solving the problem]

[0006] A continuously variable transmission according to one aspect of the present invention comprises: A shaft, a fixed sheave fixed to the shaft; a movable sheave movable on the shaft along an axis of the shaft; a lubricant flow passage formed inside the shaft; a first oil hole opening to an outer surface of the shaft and fluidly communicating with the lubricating oil passage; A primary pulley including: The first oil hole opens in the outer surface of the shaft at a position facing a cone surface of the movable sheave during underdrive. Effect of the Invention

[0007] According to the present invention, wear during high load operation can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a vehicle equipped with a continuously variable transmission according to an embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing a primary pulley. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The specific dimensions, materials, values, etc. shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0010] 1 is a schematic diagram showing a vehicle 100 equipped with a continuously variable transmission 1 according to an embodiment. For example, in this embodiment, the vehicle 100 is provided with an engine 2 as a power source. In other embodiments, the vehicle 100 may be provided with a motor (not shown) as a power source in addition to the engine 2.

[0011] For example, the engine 2 may be a gasoline engine or a diesel engine. The engine 2 rotates a crankshaft 3. The crankshaft 3 is connected to the continuously variable transmission 1 via a torque converter 4 and a turbine shaft 5.

[0012] The continuously variable transmission 1 includes a primary pulley 10, a secondary pulley 20, and a chain 30.

[0013] The primary pulley 10 is provided on the turbine shaft 5. The primary pulley 10 includes a fixed sheave 11 and a movable sheave 12. The fixed sheave 11 and the movable sheave 12 are provided on the turbine shaft 5 so as to face each other in the axial direction of the turbine shaft 5. The fixed sheave 11 and the movable sheave 12 include a cone surface 11a and a cone surface 12a, respectively. Each of the cone surface 11a and the cone surface 12a has a generally conical shape. The cone surface 11a and the cone surface 12a form a groove that holds the chain 30. The primary pulley 10 will be described in detail later.

[0014] The secondary pulley 20 is provided on the rotating shaft 6 arranged parallel to the turbine shaft 5. The secondary pulley 20 includes a fixed sheave 21 and a movable sheave 22. The fixed sheave 21 and the movable sheave 22 are provided on the rotating shaft 6 so as to face each other in the axial direction of the rotating shaft 6. The fixed sheave 21 and the movable sheave 22 include a cone surface 21a and a cone surface 22a, respectively. Each of the cone surface 11a and the cone surface 12a has a generally conical shape. The cone surface 21a and the cone surface 22a form a groove that holds the chain 30.

[0015] The chain 30 is stretched between the primary pulley 10 and the secondary pulley 20. The chain 30 functions as a power transmission element that transmits power between the primary pulley 10 and the secondary pulley 20. The power transmission element may also be called an endless member. For example, the chain 30 is configured by connecting link plates with pins. In another embodiment, a belt may be used as the power transmission element or the endless member instead of the chain 30. For example, the belt is configured by sandwiching a plurality of links (elements) between two rings.

[0016] The fixed sheave 11 of the primary pulley 10 is fixed relative to the turbine shaft 5 . The movable sheave 12 of the primary pulley 10 moves along the axis of the turbine shaft 5 by adjusting the pressure of oil supplied from a pump (not shown). Thus, in the primary pulley 10, the distance between the fixed sheave 11 and the movable sheave 12 is variable. In other words, the width of the groove that holds the chain 30 is variable. When the movable sheave 12 is farthest from the fixed sheave 11, the width of the groove is maximum, and the winding diameter of the chain 30 around the primary pulley 10 is minimum. In contrast, when the movable sheave 12 is closest to the fixed sheave 11, the width of the groove is minimum, and the winding diameter of the chain 30 around the primary pulley 10 is maximum.

[0017] Similarly, the fixed sheave 21 of the secondary pulley 20 is fixed relative to the rotating shaft 6. The movable sheave 22 of the secondary pulley 20 moves along the axis of the rotating shaft 6 by adjusting the pressure of oil supplied from a pump (not shown). Thus, in the secondary pulley 20, the distance between the fixed sheave 21 and the movable sheave 22 is variable. That is, the width of the groove that holds the chain 30 is variable. When the movable sheave 22 is farthest from the fixed sheave 21, the width of the groove is maximum, and the winding diameter of the chain 30 around the secondary pulley 20 is minimum. In contrast, when the movable sheave 22 is closest to the fixed sheave 21, the width of the groove is minimum, and the winding diameter of the chain 30 around the secondary pulley 20 is maximum.

[0018] The continuously variable transmission 1 continuously adjusts the gear ratio between the turbine shaft 5 and the rotating shaft 6 by controlling the winding diameter of the chain 30 around the primary pulley 10 and the winding diameter of the chain 30 around the secondary pulley 20.

[0019] In the present disclosure, the fixed sheave 11 and the fixed sheave 21 may also be referred to as fixed pulleys, and the movable sheave 12 and the movable sheave 22 may also be referred to as slide pulleys.

[0020] The rotating shaft 6 is connected to an output shaft 8 via a gear mechanism 7. The output shaft 8 is coupled to wheels 50. The rotating shaft 6 transmits power to the wheels 50 via the gear mechanism 7 and the output shaft 8.

[0021] Next, the primary pulley 10 will be described in detail.

[0022] FIG. 2 is a schematic cross-sectional view showing the primary pulley 10. FIG. 2 shows a cross-section along the axis X of the turbine shaft 5. FIG. 2 shows a state in which the movable sheave 12 is farthest from the fixed sheave 11. That is, in FIG. 2, the width of the groove between the fixed sheave 11 and the movable sheave 12 is maximum, and the winding diameter of the chain 30 around the primary pulley 10 is minimum. In the present disclosure, this state is referred to as "underdrive". This state corresponds to high load operation of the vehicle 100. This state also corresponds to full torque operation of the vehicle 100.

[0023] The fixed sheave 11 is fixed to the turbine shaft 5 and rotates integrally with the turbine shaft 5. The fixed sheave 11 does not move along the axis X of the turbine shaft 5.

[0024] The movable sheave 12 rotates integrally with the turbine shaft 5 and is provided movable along the axis X of the turbine shaft 5 .

[0025] Specifically, for example, the primary pulley 10 includes a back plate 13, a hydraulic chamber 14, a first flow passage 15, and a stopper 16. The primary pulley 10 may further include other components (not shown), such as a ball spline.

[0026] The back plate 13 is fixed to the turbine shaft 5 and rotates integrally with the turbine shaft 5. The back plate 13 does not move along the axis X of the turbine shaft 5.

[0027] The hydraulic chamber 14 is formed between the movable sheave 12 and the back plate 13. For example, the movable sheave 12 includes a cylindrical portion, and the back plate 13 is inserted into the cylindrical portion of the movable sheave 12. For example, a seal (not shown) may be disposed between the inner circumferential surface of the movable sheave 12 and the outer end portion of the back plate 13. The hydraulic chamber 14 is formed liquid-tight.

[0028] The first flow passage 15 is formed in the turbine shaft 5. For example, the first flow passage 15 extends along the axis X within the turbine shaft 5 to a position corresponding to the hydraulic chamber 14. The turbine shaft 5 includes one or more through holes 15a that connect the first flow passage 15 to the hydraulic chamber 14. The first flow passage 15 is in fluid communication with a pump (not shown). Oil is supplied to the hydraulic chamber 14 from the pump via the first flow passage 15.

[0029] The stopper 16 defines a limit for the movement of the movable sheave 12 in the direction away from the fixed sheave 11. For example, the stopper 16 may be a protrusion that protrudes radially from the turbine shaft 5. The stopper 16 is not limited to this, and other configurations that can restrict the movement of the movable sheave 12 in the direction away from the fixed sheave 11 may be used.

[0030] In FIG. 2, the hydraulic pressure in the hydraulic chamber 14 is low, and the movable sheave 12 is in contact with the stopper 16. When the hydraulic pressure in the hydraulic chamber 14 increases, the movable sheave 12 is pushed by the oil and moves in a direction approaching the fixed sheave 11. With this configuration, the distance between the cone surface 11a of the fixed sheave 11 and the cone surface 12a of the movable sheave 12 is adjusted. The radial position of the pin 31 of the chain 30 changes depending on the distance between the cone surface 11a and the cone surface 12a. Therefore, the winding diameter of the chain 30 around the primary pulley 10 can be adjusted.

[0031] When the vehicle 100 shown in FIG. 2 is in underdrive, the winding diameter of the chain 30 around the primary pulley 10 is small. Therefore, the contact area between the chain 30 and the cone surfaces 11a and 12a is small. In this case, friction between the chain 30 and the cone surfaces 11a and 12a increases. Therefore, in this embodiment, the continuously variable transmission 1 has a configuration for reducing friction at the primary pulley 10 when in underdrive.

[0032] Specifically, for example, the primary pulley 10 includes a second flow passage 17, a plurality of first oil holes 18a, and a plurality of second oil holes 18b. The primary pulley 10 may further include other components (not shown).

[0033] The second flow passage 17 is formed in the turbine shaft 5. For example, the second flow passage 17 extends along the axis X within the turbine shaft 5 to a position between the fixed sheave 11 and the movable sheave 12. The second flow passage 17 is separated from the first flow passage 15. The second flow passage 17 is in fluid communication with another pump (not shown). The second flow passage 17 is supplied with lubricating oil from the pump. In the present disclosure, the second flow passage 17 is also referred to as a "lubricating oil flow passage."

[0034] The first oil hole 18a opens to the outer surface of the turbine shaft 5. The first oil hole 18a is connected to the second flow passage 17. The first oil hole 18a penetrates the wall of the turbine shaft 5 from the second flow passage 17 to the outer surface of the turbine shaft 5.

[0035] The first oil hole 18a opens at a position facing the cone surface 12a of the movable sheave 12 in underdrive on the outer surface of the turbine shaft 5. Specifically, the first oil hole 18a opens at a position between the fixed sheave 11 and the movable sheave 12 in underdrive and close to the movable sheave 12 on the outer surface of the turbine shaft 5. More specifically, in this embodiment, the first oil hole 18a opens at a position continuous with the cone surface 12a in underdrive.

[0036] In the cross section shown in FIG. 2, the first oil hole 18a extends in a direction along the cone surface 12a of the movable sheave 12. Specifically, the first oil hole 18a is inclined with respect to the radial direction of the turbine shaft 5. More specifically, the angle between the radial direction and the extension direction of the first oil hole 18a is equal to the angle between the radial direction and the cone surface 12a. In other embodiments, in the cross section shown in FIG. 2, the angle between the radial direction and the extension direction of the first oil hole 18a may be different from the angle between the radial direction and the cone surface 12a.

[0037] Fig. 3 is a schematic cross-sectional view taken along line III-III in Fig. 2. Fig. 3 shows a cross-section perpendicular to the axis X of the turbine shaft 5. Fig. 3 shows only the turbine shaft 5 for better understanding.

[0038] In the cross section shown in Fig. 3, the first oil holes 18a extend in the radial direction. In another embodiment, in the cross section shown in Fig. 3, the first oil holes 18a may be inclined with respect to the radial direction.

[0039] In this embodiment, three first oil holes 18a are formed in the turbine shaft 5. The number of first oil holes 18a is not limited to three, and may be one, two, or four or more.

[0040] 2, the second oil hole 18b opens to the outer surface of the turbine shaft 5. The second oil hole 18b is connected to the second flow passage 17. The second oil hole 18b penetrates the wall of the turbine shaft 5 from the second flow passage 17 to the outer surface of the turbine shaft 5.

[0041] The second oil hole 18b opens in the outer surface of the turbine shaft 5 at a position facing the cone surface 11a of the fixed sheave 11. Specifically, the second oil hole 18b opens in the outer surface of the turbine shaft 5 at a position between the fixed sheave 11 and the movable sheave 12 in underdrive and close to the fixed sheave 11. More specifically, in this embodiment, the second oil hole 18b opens in a position continuous with the cone surface 11a.

[0042] In the cross section shown in FIG. 2, the second oil hole 18b extends in a direction along the cone surface 11a of the fixed sheave 11. Specifically, the second oil hole 18b is inclined with respect to the radial direction of the turbine shaft 5. More specifically, the angle between the radial direction and the extension direction of the second oil hole 18b is equal to the angle between the radial direction and the cone surface 11a. In other embodiments, in the cross section shown in FIG. 2, the angle between the radial direction and the extension direction of the second oil hole 18b may be different from the angle between the radial direction and the cone surface 11a.

[0043] Fig. 4 is a schematic cross-sectional view taken along line IV-IV in Fig. 2. Fig. 4 shows a cross-section perpendicular to the axis X of the turbine shaft 5. Fig. 4 shows only the turbine shaft 5 for better understanding.

[0044] In the cross section shown in Fig. 4, the second oil holes 18b extend in the radial direction. In another embodiment, in the cross section shown in Fig. 4, the second oil holes 18b may be inclined with respect to the radial direction.

[0045] In this embodiment, three second oil holes 18b are formed in the turbine shaft 5. The number of second oil holes 18b is not limited to three and may be one, two, or four or more. The number of second oil holes 18b may be different from the number of first oil holes 18a.

[0046] 2, when the continuously variable transmission 1 is in underdrive, lubricating oil is supplied to the second flow passage 17 from a pump (not shown). A part of the lubricating oil is injected from the first oil hole 18a toward the cone surface 12a of the movable sheave 12. The first oil hole 18a extends in a direction along the cone surface 12a. Therefore, the lubricating oil is easily supplied along the cone surface 12a to the contact area between the pin 31 of the chain 30 and the cone surface 12a. As a result, wear between the pin 31 and the cone surface 12a is reduced.

[0047] The rest of the lubricating oil supplied to the second flow passage 17 is injected from the second oil hole 18b toward the cone surface 11a of the fixed sheave 11. The second oil hole 18b extends in a direction along the cone surface 11a. Therefore, the lubricating oil is easily supplied along the cone surface 11a to the contact area between the pin 31 and the cone surface 11a. As a result, wear between the pin 31 and the cone surface 11a is reduced.

[0048] When the vehicle 100 shifts from underdrive to another drive mode and the pressure of the oil from the pump (not shown) to the hydraulic chamber 14 increases, the movable sheave 12 moves along the axis X of the turbine shaft 5 so as to approach the fixed sheave 11. This causes the pin 31 to move radially outward, and the winding diameter of the chain 30 around the primary pulley 10 decreases. In addition, the first oil hole 18a is closed by the movable sheave 12. Therefore, the lubricating oil is injected only from the second oil hole 18b toward the cone surface 11a of the fixed sheave 11. As a result, wear between the pin 31 and the cone surface 11a is reduced. In addition, a part of the lubricating oil is supplied to the contact area between the pin 31 and the cone surface 12a of the movable sheave 12 through the pin 31. As a result, wear between the pin 31 and the cone surface 12a is reduced. With this configuration, the amount of lubricant supplied to the contact area between the primary pulley 10 and the chain 30 can be increased during underdrive and reduced during other drive modes.

[0049] The continuously variable transmission 1 as described above includes a primary pulley 10 including a turbine shaft 5, a fixed sheave 11 fixed to the turbine shaft 5, a movable sheave 12 movable on the turbine shaft 5 along the axis X of the turbine shaft 5, a second flow passage 17 formed inside the turbine shaft 5, and a first oil hole 18a opening on the outer surface of the turbine shaft 5 and fluidly communicating with the second flow passage 17, and the first oil hole 18a opens at a position on the outer surface of the turbine shaft 5 facing the cone surface 12a of the movable sheave 12 during underdrive. With this configuration, lubricating oil can be supplied to the contact area between the pin 31 of the chain 30 and the cone surface 12a during underdrive. Therefore, wear during high load operation can be reduced. Also, with this configuration, the first oil hole 18a can be closed by the movable sheave 12 during other drive modes. Therefore, the amount of lubricating oil supplied to the contact area between the primary pulley 10 and the chain 30 can be adjusted depending on the drive mode.

[0050] Furthermore, in the continuously variable transmission 1, the first oil hole 18a extends in a direction along the cone surface 12a of the movable sheave 12 in a cross section along the axis X of the turbine shaft 5. With this configuration, the lubricating oil is easily supplied along the cone surface 12a to the contact area between the pin 31 of the chain 30 and the cone surface 12a. As a result, wear between the pin 31 and the cone surface 12a is further reduced.

[0051] In addition, in the continuously variable transmission 1, the primary pulley 10 further includes a second oil hole 18b that opens on the outer surface of the turbine shaft 5 and is fluidly connected to the second flow passage 17, and the second oil hole 18b opens on the outer surface of the turbine shaft 5 at a position facing the cone surface 11a of the fixed sheave 11. With this configuration, it is possible to supply lubricating oil to the contact area between the pin 31 of the chain 30 and the cone surface 11a. Therefore, wear between the pin 31 and the cone surface 11a is reduced. Furthermore, with this configuration, it is possible to constantly supply lubricating oil from the second oil hole 18b to the contact area between the primary pulley 10 and the chain 30 regardless of the drive mode.

[0052] In the continuously variable transmission 1, the second oil hole 18b extends in a direction along the cone surface 11a of the fixed sheave 11 in a cross section along the axis X of the turbine shaft 5. With this configuration, the lubricating oil is easily supplied along the cone surface 11a to the contact area between the pin 31 and the cone surface 11a. As a result, wear between the pin 31 and the cone surface 11a is further reduced.

[0053] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0054] 1. Continuously variable transmission 5 Turbine shaft (shaft) 10 Primary pulley 11 Fixed sheave 11a Cone surface 12 Movable sheave 12a Cone surface 17 Second flow path (lubricating oil flow path) 18a 1st oil hole 18b 2nd oil hole X Axis of turbine shaft

Claims

1. A shaft, a fixed sheave fixed to the shaft; a movable sheave movable on the shaft along an axis of the shaft; a lubricant flow passage formed inside the shaft; a first oil hole opening to an outer surface of the shaft and fluidly communicating with the lubricating oil passage; A primary pulley including: The first oil hole opens at a position on the outer surface of the shaft facing a cone surface of the movable sheave during underdrive. Continuously variable transmission.

2. The continuously variable transmission according to claim 1 , wherein the first oil hole extends in a direction along the cone surface of the movable sheave in a cross section taken along the axis of the shaft.

3. The primary pulley further includes a second oil hole that opens to an outer surface of the shaft and is in fluid communication with the lubricating oil passage, 3. The continuously variable transmission according to claim 1, wherein the second oil hole opens at a position on the outer surface of the shaft facing a cone surface of the fixed sheave.

4. The continuously variable transmission according to claim 3 , wherein the second oil hole extends in a direction along the cone surface of the fixed sheave in a cross section taken along the axis of the shaft.

Images