JP3644484B2 - Parking mechanism for belt type continuously variable transmission for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a parking mechanism for a vehicular belt type continuously variable transmission called a so-called CVT.
[0002]
[Related background]
For example, in a continuously variable transmission described in Japanese Patent Application Laid-Open No. 5-280607, a primary shaft and a secondary shaft are arranged in parallel in a casing, and a primary pulley provided on the primary shaft and a secondary pulley provided on a secondary shaft are arranged. An endless belt is stretched over. The primary pulley and the secondary pulley are each composed of a fixed sheave and a movable sheave, and the movable sheave is movable in the axial direction by an actuator. And the interval of each sheave is adjusted by the hydraulic pressure supplied to the actuator, etc., so that the gear ratio can be changed steplessly. The driving force of the engine shifted to the stepless diameter is transmitted to the driving wheel side through a differential gear or the like.
[0003]
On the other hand, this type of continuously variable transmission needs to be provided with a parking mechanism for preventing movement of the vehicle during parking. In the continuously variable transmission described above, a parking gear is provided on the secondary shaft as a parking mechanism. A lever-shaped sprag is disposed in the proximity position, and the sprag is pivotally attached to a support portion provided on the inner wall of the casing. The sprag is mechanically linked to the shift lever of the driver's seat. When the driver switches the shift lever to the P (parking) position during parking, the sprag rotates and the tip is hooked on the outer periphery of the parking gear. The rotation of the secondary shaft, that is, the movement of the vehicle is restricted.
[0004]
The above-described support portion is cast into the inner wall of the casing at the same time when the casing is formed by aluminum die casting or the like, and thereafter machined into a pin hole for supporting the sprag, a guide surface in sliding contact with the sprag, or the like.
[0005]
[Problems to be solved by the invention]
By the way, during parking, the reaction force when the vehicle is stopped and held acts on the tip of the sprag via the parking gear, and is further applied to the support portion as a moment from the tip of the sprag to the center of rotation (support portion). Will work. Therefore, in order to reduce the moment, it is desirable to shorten the distance from the tip of the sprag to the support portion, in other words, to bring the position of the support portion closer to the parking gear. However, for the convenience of casting the support part, it is necessary to machine the support part in the narrow casing as described above, so that the installation position is limited, and as a result, the support part starts from the tip of the sprag. It has been difficult to shorten the distance to the end, and there has been a problem that it is difficult to ensure sufficient strength of the support portion.
[0006]
An object of the present invention is to provide a vehicular belt-type continuously variable transmission capable of reducing a moment acting on a support portion by providing a sprag support portion at a position close to a parking gear, thereby ensuring a sufficient strength of the support portion. It is to provide a parking mechanism of a machine.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a primary shaft to which engine rotation is input and a secondary shaft arranged in parallel to the primary shaft are accommodated in a casing, and the primary shaft and the secondary shaft are accommodated by an actuator. In a belt-type continuously variable transmission for a vehicle, in which a driven pulley is provided and a belt is stretched between both pulleys, a forward / reverse switching mechanism for switching the forward / backward movement of the vehicle is accommodated and fixed detachably in the casing. Housing member, a shift operation device capable of switching the operating range of the belt type continuously variable transmission, a parking gear provided on the secondary shaft, and a parking gear engaged with the switching operation of the shift operation device A latch member that can regulate the rotation of the secondary shaft, and a support portion that is provided on the housing member and supports the latch member. It was.
[0008]
Accordingly, since the support portion is provided on the housing member, the support portion can be machined in a state of the housing member alone. For example, the support portion is provided in the narrow casing as in the case where the support portion is provided in the casing. Since it becomes unnecessary to process, there is no possibility that the support part is limited to a position where it can be processed, and the degree of freedom regarding the installation position of the support part is expanded.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied as a parking mechanism of a belt type continuously variable transmission used in an FF (front engine / front drive) vehicle will be described.
FIG. 1 shows a cross section of a belt-type continuously variable transmission, and an engine (not shown) is connected to the right side of the continuously variable transmission in the figure. An input shaft 2 and a primary shaft 3 are coaxially arranged in a casing 1 of the continuously variable transmission, and a right end of the input shaft 2 is connected to an engine crankshaft 5 via a torque converter 4. The left end of the input shaft 2 is supported by the right end of the primary shaft 3 via a forward / reverse switching mechanism 6 including a planetary gear mechanism, a forward clutch, a reverse clutch, etc. (not shown). A primary pulley 7 is provided on the primary shaft 3. It has been. The forward / reverse switching mechanism 6 is accommodated in a brake support 8 as a cup-shaped housing member that opens to the right in the drawing, and the opening of the brake support 8 is closed by a reaction support 9.
[0010]
The outer periphery on the left side of the brake support 8 is fitted to the inner wall of the casing 1, and the flange portion 8 a formed on the outer periphery on the right side of the brake support 8 and the outer periphery of the reaction support 9 are overlapped with each other. The brake support 8 and the reaction support 9 are positioned and fixed in the casing 1 as a result. The reaction support 9 has an inner periphery that supports the right end of the input shaft 2 via a shaft 25 and a bearing 26 that support a stator (not shown) of the torque converter 4, and a left inner periphery of the brake support 8 that has a bearing 11 and a primary shaft. 3. It plays the role of supporting the right end of the primary shaft 3 and the left end of the input shaft 2 via the bearing 27.
[0011]
The primary pulley 7 includes a fixed sheave 7a formed integrally with the primary shaft 3 and a movable sheave 7b provided so as to be movable on the primary shaft 3. The movable sheave 7b is fixed to the fixed sheave 7a by a hydraulic actuator 13. Can come and go. A secondary shaft 14 is disposed in the casing 1 in parallel with the primary shaft 3, and a secondary pulley 15 is provided on the secondary shaft 14. Similar to the primary pulley 7 described above, the secondary pulley 15 includes a fixed sheave 15a formed integrally with the secondary shaft 14 and a movable sheave 15b provided movably on the secondary shaft 14, and the movable sheave 15b is The hydraulic actuator 16 can be moved toward and away from the fixed sheave 15a.
[0012]
An endless metal belt 17 is stretched between the primary pulley 7 and the secondary pulley 15, and this metal belt 17 is a V-shaped formed between the fixed sheaves 7a and 15a and the movable sheaves 7b and 15b. The rotation of the primary pulley 7 is transmitted to the secondary pulley 15 by being sandwiched in the groove 18. The movable sheaves 7b and 15b of the primary pulley 7 and the secondary pulley 15 are always driven in opposite directions by the hydraulic actuators 13 and 16, and accordingly, the effective diameter of one of the primary pulley 7 and the secondary pulley 15 increases and the other The effective diameter of is reduced. When the effective diameter of the primary pulley 7 is larger than the effective diameter of the secondary pulley 15, the gear ratio shifts to the high speed (overdrive) side, and conversely, the effective diameter of the primary pulley 7 becomes the effective diameter of the secondary pulley 15. When the comparison is smaller, the gear ratio shifts to the low speed (low) side.
[0013]
A transfer drive gear 20 is spline-coupled on the secondary shaft 14, and the transfer drive gear 20 meshes with a transfer-brin gear 22 spline-coupled on the transfer shaft 21. A pinion gear 21 a is integrally formed on the transfer shaft 21. The pinion gear 21 a meshes with a final gear 23 a of a differential mechanism 23, and the differential mechanism 23 is connected to left and right drive wheels (not shown) via a drive shaft 24. Yes.
[0014]
FIG. 2 is an explanatory diagram showing the positional relationship between the brake support and the parking gear. A parking gear 31 is splined on the secondary shaft 14. A pair of support portions 32 (only one is shown) is integrally formed on the outer periphery of the brake support 8, and although not shown, both support portions 32 are in the axial direction of the secondary shaft 14 (direction perpendicular to the paper surface of FIG. 2). It is provided with a predetermined interval and corresponds to the parking gear 31. A lever-shaped sprag 33 as a latching member is disposed between the support portions 32, and the central portion of the sprag 33 is pivotable by a pin 34 inserted into the pin hole 32 a of the support portions 32. It is worn. The tip 33 a of the sprag 33 is formed to project toward the parking gear 31, and can be hooked on the outer periphery of the parking gear 31 as the sprag 33 rotates. The opposing surfaces of the two support portions 32, that is, the surfaces that are in sliding contact with the side surfaces of the sprags 33 are formed by casting. For this reason, by forming the support portion 32 on the brake support 8 which is separate from the casing 1, the casting depth becomes shallow, the casting gradient becomes gentle, and machining can be made unnecessary. The pin hole 32a of the support part 32 is formed by machining.
[0015]
Although not shown, the base end 33b of the sprag 33 is mechanically connected to a shift lever as a shift operation device provided in the driver's seat of the vehicle, and the shift lever is switched to the P (parking) position. When this is done, the sprag 33 rotates counterclockwise as shown by the solid line, and the tip of the sprag 33 is hooked on the outer periphery of the parking gear 31, while the shift lever is D (drive) or N (neutral). When the position is switched to a position other than the P position, the sprag 33 rotates clockwise as shown by the phantom line, and the tip is separated from the parking gear 31.
[0016]
Next, the operation state of the parking mechanism of the vehicle belt type continuously variable transmission configured as described above will be described.
When the shift lever is in a position other than the P position as described above, the tip of the sprag 33 is separated from the outer periphery of the parking gear 31 as indicated by the phantom line in FIG. The vehicle can be arbitrarily driven. When the shift lever is switched to the P position from this state, the sprag 33 rotates to the position indicated by the solid line, and the tip is latched on the outer periphery of the parking gear 31. As a result, the rotation of the secondary shaft 14 together with the parking gear 31 is restricted, and the transfer drive gear 20, the transfer blind gear 22, the transfer shaft 21, the pinion gear 21a, the differential device 23, which are downstream members in the power transmission direction, The drive wheels are prevented from rotating through the drive shaft 24, and the movement of the vehicle is restricted.
[0017]
On the other hand, in the parking mechanism of the belt type continuously variable transmission for a vehicle according to the present embodiment, the support portion 32 that is the rotation center of the sprag 33 is provided on the brake support 8 as described above. As a result, the degree of freedom regarding the installation position of the support portion 32 can be expanded. The reason for this will be described in detail below. The brake support 8 is formed by aluminum die casting or the like. At that time, the support portion 32 is also cast at the same time, and then the pin hole 32a of the support portion 32 is drilled. The final shape of the support portion 32 is adjusted. At this time, the guide surface is formed in a cast shape or by cutting with a milling cutter or the like. And since these machining is performed in the state of the brake support 8 single-piece | unit, even if the support part 32 is located anywhere on the outer periphery of the brake support 8, processing can be implemented very easily. Therefore, there is no possibility that the support portion is limited to a position where the support portion can be processed as in the conventional example (Japanese Patent Laid-Open No. 5-280607) in which the support portion needs to be processed in a narrow casing. The degree of freedom regarding position can be greatly expanded.
[0018]
In addition, in the conventional example in which the support portion is provided on the casing side, the support portion is cast when the casing is molded, so that the support portion cannot be cast unless the support portion is set outside the locus of the metal belt. The position of the part is limited to the outside of the belt locus. On the other hand, in the present embodiment, since the support portion 32 is provided on the brake support 8 which is a separate component from the casing 1, the position of the support portion 32 can be set regardless of the belt locus. Therefore, as shown in FIG. 2, the support part 32 can also be provided in the belt locus | trajectory S, and the freedom degree regarding the installation position of the above-mentioned support part 32 can further be expanded.
[0019]
Due to the above factors, the support portion 32 can be disposed in the vicinity of the parking gear 8, and the distance L from the tip of the sprag 33 to the support portion 32 can be shortened, and thus acts on the support portion 32 during parking. The moment can be reduced and sufficient strength of the support portion 32 can be ensured.
In addition to the processing of the support portion 32 described above, the subsequent work of attaching the sprag 33 to the support portion 32 can be performed in the state of the brake support 8 alone before being assembled to the casing 1. Accordingly, there is an advantage that the operations can be simplified and the manufacturing cost can be reduced as compared with the conventional example in which these operations need to be performed in a narrow casing.
[0020]
This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above-described embodiment, the invention is embodied as a parking mechanism for a belt-type continuously variable transmission for FF vehicles. However, the type of a vehicle to be applied is not limited. You may actualize in the parking mechanism of a continuously variable transmission.
[0021]
In the above embodiment, the sprag 33 is rotated and the parking gear 31 is embodied by the tip of the sprag 33. However, the parking mechanism 31 is essentially a member (sprag 33) that latches the parking gear 31. ) Is supported on the brake support 8 side, the form is not limited. Therefore, for example, the sprag 33 may be slidably supported on the brake support 8, and the tip of the sprag 33 may be hooked on the parking gear 31 as the slide occurs. Even in this case, since the support part of the sprag 33 can be installed at an arbitrary position, the distance L from the tip to the support part can be shortened.
[0022]
Furthermore, in the above-described embodiment, the support portion 32 is disposed in the locus S of the metal belt 17, but it is not always necessary to be in the locus S. The support portion 32 is disposed outside the locus S depending on the peripheral component layout or the like. As a result, the distance L of the sprag 33 may be shortened as a result. Therefore, in such a case, the support portion 32 may be disposed outside the locus S of the metal belt 17.
[0023]
【The invention's effect】
As described above, according to the parking mechanism of the belt type continuously variable transmission for a vehicle of the present invention, since the support portion can be processed in a state of the housing member alone, the restriction on the processing is eliminated, The degree of freedom regarding the installation position of the support portion can be greatly expanded. As a result, it is possible to reduce the moment acting on the support portion by providing the support portion in the vicinity of the parking gear, thereby ensuring sufficient strength of the support portion.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a belt type continuously variable transmission for a vehicle according to an embodiment.
FIG. 2 is an explanatory diagram showing a positional relationship between a brake support and a parking gear.
[Explanation of symbols]
1 Casing 3 Primary shaft 6 Forward / reverse switching mechanism 7 Primary pulley 8 Brake support (housing member)
13 Hydraulic Actuator 14 Secondary Shaft 15 Secondary Pulley 16 Hydraulic Actuator 17 Metal Belt 31 Parking Gear 32 Support Portion 33 Sprag (Hanging Member)

Claims (1)

A primary shaft to which engine rotation is input and a secondary shaft arranged in parallel to the primary shaft are accommodated in a casing, and pulleys driven by an actuator are provided on the primary shaft and the secondary shaft. In a belt type continuously variable transmission for a vehicle in which a belt is stretched between pulleys,
Housing a forward / reverse switching mechanism for switching forward / backward movement of the vehicle, and a housing member detachably fixed in the casing;
A shift operation device capable of switching the operation range of the belt-type continuously variable transmission;
A parking gear provided on the secondary shaft;
A latch member that latches the parking gear in accordance with the switching operation of the shift operation device, and can regulate the rotation of the secondary shaft;
A parking mechanism for a belt type continuously variable transmission for a vehicle, comprising: a support portion provided on the housing member and supporting the latch member.

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