JPH0830526B2 - Pulley shaft support device for continuously variable transmission - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley shaft supporting device for a belt type continuously variable transmission of a vehicle, and more particularly, to a structure of a bearing which simultaneously receives a radial load by a belt and a thrust load by a gear.

[Prior art]

Conventionally, as for a gear train of a belt type continuously variable transmission of this type, there is, for example, a prior art disclosed in JP-A-59-175664. Here, the belt is wound around the primary pulley of the main shaft and the secondary pulley of the auxiliary shaft, and the auxiliary shaft is further configured to be transmitted through an intermediate reduction gear. Here, the gear is a normal gear, which is a ball bearing that acts on the secondary pulley side by the reaction force in the axial direction during driving, positions the pulley one side near the secondary pulley, and supports the sub-shaft. It is shown to be subject to loads and thrust loads from the gears.

[Problems to be Solved by the Invention]

By the way, in the ball bearing, the radius of curvature Ri of the ball receiving portion of the inner race is generally 0 with respect to the diameter d of the ball.
It is 51d or more, and the radius of curvature Ro of the ball receiving portion of the outer race is set to 0.53d or more, and even if there is some axial deviation between the inner race and the outer race, it can be absorbed. Therefore, when such a ball bearing is used to support the shaft of the secondary pulley, the thrust load of the gear shifts the bearing in the axial direction to move the secondary pulley to one side, causing misalignment of the secondary pulley with respect to the primary pulley (misalignment). ) Becomes larger than necessary. The misalignment varies with changes in thrust load due to the driving force of the gear. Here, the misalignment between the primary pulley and the secondary pulley is set to a minimum. That is, if this misalignment is large, the belt will meander, and the side edges of the ring hung on a large number of single-row elements will come into contact with the elements and be damaged, thereby impairing the durability of the belt. Therefore, it is desired to suppress the axial displacement of the ball bearing described above and prevent the misalignment of the pulley from increasing. The present invention has been made in view of the above circumstances, and is intended to improve the durability of a belt by positioning a pulley to restrict axial displacement of a ball bearing that receives a radial load and a thrust load. An object of the present invention is to provide a pulley shaft support device for a continuously variable transmission.

[Means for solving problems]

In order to achieve the above object, the present invention rotatably supports one pulley shaft constituting a belt type continuously variable transmission by a ball bearing arranged in the vicinity of the pulley so that the pulley is positioned at the same time. In the structure that receives the thrust load by the gear attached to the shaft and the radial load by the belt at the same time, the radius of curvature of each ball receiving portion of the inner race and the outer race of the above ball bearing, the radius of curvature on the inner race side is the ball diameter. The radius of curvature on the outer race side is set to 50.1 to 50.9% to 50.1 to 50.9% of the ball diameter, and is set to be smaller than the normal standard setting value so as to approximate the curvature of the ball.

[Action]

Based on the above configuration, the axial displacement between the inner race and the outer race of the ball bearing, which is also installed near the pulley and also serves as positioning, is set to be extremely small, so that the pulley moves even if a frust load is applied by the gear. That is, the misalignment between the primary pulley and the secondary pulley does not increase. Thus, in the present invention, the positioning function of the ball bearing that positions and supports the pulley is enhanced, and the durability of the belt can be improved.

【Example】

An embodiment of the present invention will be specifically described below with reference to the drawings. Referring to FIG. 1, an example of a transmission system of a belt type continuously variable transmission combined with an electromagnetic powder type clutch will be described as an application of the present invention. Reference numeral 1 is an electromagnetic powder type clutch, and 2 is a continuously variable transmission. The continuously variable transmission 2 is roughly classified into a forward-reverse switching section 3, a pulley ratio converting section 4, and a final reduction section 5 which are configured to be transmitted from the input side. The electromagnetic powder clutch 1 is housed in one of the clutch housings 6,
Inside the other side of the clutch housing 6, the main case 7 joined thereto, and the side case 8 joined to the side of the main case 7 opposite to the clutch housing 6,
The continuously variable transmission 2 includes a switching unit 3, a pulley ratio conversion unit 4, and a final reduction unit 5. The electromagnetic powder clutch 1 is a crankshaft 10 from the engine.
A ring-shaped drive member 12 integrally connected to the transmission plate 11 via a drive plate 11 and a disk-shaped driven member 14 integrally spline-connected to the transmission input shaft 13 in the rotational direction. Then, a coil is provided on the outer peripheral side of the driven member 14.
A gap 16 is formed along the circumference between both members 12 and 14 by incorporating 15 therein, and the gap 16 communicates with a powder chamber 17 having electromagnetic powder therein. Further, the power feeding brush 19 is slidably contacted with the slip ring 18 of the hub portion of the driven member 14 including the coil 15, and the slip ring 18 further passes through the inside of the driven member 14 and is connected to the coil 15 to form a clutch current circuit. There is. In this way, when a clutch current is passed through the coil 15, the magnetic powder generated between the drive and the even members 12, 14 through the gap 16 causes the electromagnetic powder to be bound and accumulated in the gap 16 in a chain, and by the binding force by this. Drive member
The driven member 14 slides into the 12 and is integrally connected,
The clutch is engaged. On the other hand, if the clutch current is cut off, the electromagnetic powder drive and driven member 1
The coupling force of 2,14 disappears and the clutch is disengaged. If the control of the clutch current in this case is performed in conjunction with the operation of the switching unit 3 of the continuously variable transmission 2, the forward drive (D) and the sporty drive from the parking (P) or neutral (N) range are performed. When the drive (Ds) or reverse (R) range is switched, the clutch 1 is automatically engaged or disengaged, and the clutch pedal operation becomes unnecessary. Next, in the continuously variable converter 2, the switching portion 3 includes the input shaft 13 from the clutch 1 and the main shaft 20 coaxially arranged with the input shaft 13.
It is provided between and. That is, a reverse drive gear 21 that doubles as a forward engaged side is formed on the input shaft 13, and a reverse engaged side gear 22 is rotatably fitted to the main shaft 20. , 22 supported by a shaft 23, a counter gear 24, a shaft 2
It is configured to mesh via an idler gear 26 supported by 5. A switching mechanism is provided between the main shaft 20 and the gears 21 and 22.
27 are provided. Here, the gear 2 that is always meshed
1, 24, 26, 22 are connected to the driven member 14 having the coil 15 of the clutch 1, and the switching mechanism 27 has a main shaft corresponding to the fact that the inertial mass of this portion is relatively large when the clutch is disengaged.
A sleeve 29, which is spline-fitted to the hub 28 of 20, is configured to be meshed and coupled to the gears 21 and 22 via the synchronizing mechanisms 30 and 31. As a result, when the sleeve 29 is meshed with the gear 21 side via the synchronizing mechanism 30, the main shaft 20 is directly connected to the input shaft 13 and is in a forward movement state. On the other hand, reverse the sleeve 29 and synchronize
When meshed with the gear 22 side via 31, the input shaft 13 becomes
It is connected to the main shaft 20 via 1, 24, 26 and 22, and the engine power decelerates and reverses to enter the reverse state. In the pulley ratio conversion unit 4, a sub shaft 35 is arranged in parallel to the main shaft 20, a primary pulley 36 and a second pulley 37 are provided on both shafts 20 and 35, respectively, and both pulleys 36,
An endless drive belt 34 is hung between 37.
Each of the pulleys 36, 37 is divided into two parts. One of the fixed pulleys 36a, 37a is movable with respect to the other movable pulleys 36b, 37b so as to change the pulley interval.
37b includes a hydraulic servo device 38 which also functions as a piston.
39 is attached, and the movable pulley 37 of the secondary pulley 37 is further attached.
A spring 40 is urged on b in a direction to reduce the pulley interval. Further, an oil pump 41 as an operation source is installed next to the primary pulley 36 as a hydraulic control system. The oil pump 41 is a gear pump for high pressure, and the pump drive shaft 42 penetrates the inside of the primary pulley 36, the main shaft 20 and the input shaft 13 and is directly connected to the crankshaft 10 so that hydraulic pressure is constantly generated during engine operation. ing. And this oil pump 41
Control the hydraulic pressure of to supply and discharge oil to each hydraulic servo device 38, 39,
By changing the pulley distance between the primary pulley 36 and the secondary pulley 37 in an inverse relationship, the pulley ratio of the drive belt 34 between the pulleys 36, 37 is converted in a stepless manner, and continuously stepped power is output to the auxiliary shaft 35. The final deceleration unit 5 has a minimum pulley ratio of the pulley conversion unit 4 on the high-speed stage side of, for example, 0.5, which is very small. Therefore, the rotation speed of the sub shaft 35 is large. The output shaft 44 is connected via the gear 43. Then, the final gear 46 meshes with the drive gear 45 of the output shaft 44,
It is configured to be transmitted from the final gear 46 to the wheels 48 and 49 of the left and right driving wheels via the operating mechanism 47. On the other hand, to describe the support device on the secondary pulley side, the roller bearing 50 is installed on the side of the clutch shaft adjacent to the drive gear 43a of the gear 43 on the counter shaft 35. Further, a ball bearing 51 is installed on the side of the secondary pulley 37 adjacent to the fixed pulley 37a on the side case side.
Ball bearing 51 is inner race 51a, outer race 51
b and ball 51c, and inner race 51a with countershaft 35
Is locked to the stepped portion 35a and fastened with the lock nut 52,
The outer race 51b is fitted in the side case recess 8a, and the plate 53 prevents the outer race 51b from being attached. The roller bearing 50 is also attached in substantially the same manner. Here, since the gear 43 is a helical gear, the drive gear 43
When driving (a), the thrust load Fs, which is an axial reaction force, acts on the pulley side as indicated by the solid arrow, and during deceleration and reverse (R), the thrust load Fs reverses as indicated by the dashed arrow. To work. The bearings 50 and 51 both position the secondary pulley 37 and the auxiliary shaft 35 in the axial direction and rotatably support them. The ball bearing 51 receives most of the radial load F _R due to the belt tension and the thrust load Fs at the time of driving, which is larger than that during deceleration. Therefore, the axial displacement of the ball bearing 51 due to the thrust load F _S during driving directly affects the deviation between the centers Op and Os of the primary and secondary pulleys 36 and 37. Therefore, the structure of the ball bearing 51 itself is as shown in FIG. That is, the diameter of the ball 51c
d, the radius of curvature of the ball receiving portion 51d of the inner race 51a is Ri,
If the radius of curvature of the ball receiving portion 51e of the outer race 51b is Ro, then Ri, Ro> d / 2 to satisfy the bearing. Therefore, in general, Ri> 0.51d and Ro> 0.53d are set to absorb some axial displacement of the inner race 51a and the outer race 51b. However, the curvature of both ball receiving portions 51d and 51e is approximated to that of the ball 51c to regulate the axial displacement, and the radius of curvature Ri, Ro
Is set as Ri = 0.501 to 0.509d Ro = 0.501 to 0.519d below the above general one. As a result, the axial displacement has a smaller characteristic as shown by the solid line than the conventional example shown by the broken line in FIG. 2 (b). Further, FIG. 2 (c) shows measured data according to the present invention, in which the axial load and the radial load equivalent to that of the continuously variable transmission at the minimum gear ratio fully open running are set with the radius of curvature Ri of the inner race being 0.505d. It shows the axial displacement when According to this, the smaller the radius of curvature Ro of the outer race, the smaller the displacement tends to be. However, as described above, since Ro> 0.50d should theoretically be satisfied, the value in the above range is derived. With the above configuration, the engine power is input to the primary pulley 36 of the pulley ratio conversion unit 4 via the forward / reverse switching unit 3 by the engagement of the clutch 1, and the power continuously variable by the pulleys 36, 37 and the belt 34 is subordinate. It is output to the shaft 35, and this is transmitted to the wheel side after the gear 43 to drive the vehicle. At this time, the ball bearing 51 receives the radial load F _R and the thrust load Fs that have changed according to the transmission torque, but the axial displacement of the ball bearing 51 is restricted to the minimum, so that the second pulley 37 Movement due to thrust load Fs is also restricted. Therefore, the misalignment of the pulleys 36, 37 is maintained at the designed initial value, and the belt 34 is prevented from meandering more than necessary. Although it is possible to use a multi-point contact bearing of three or four points as a ball bearing with little axial displacement, it is necessary to consider measures against radial load due to a large belt.

【The invention's effect】

As described above, according to the present invention, the radius of curvature of each ball receiving portion of the inner race and the outer race of the ball bearing is smaller than the normal standard setting value (51%, 53%) with respect to the ball diameter. Since the axial load between the inner race and the outer race is smaller than the normal one when the thrust load by the gear attached to the shaft acts on the pulley shaft, Misalignment is minimized. As a result, the function of positioning the pulley by the ball bearing is enhanced, and the durability of the belt can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a pulley shaft supporting device of the present invention, and FIG. 2 (a) is a sectional view of a ball bearing,
(B) is a bearing characteristic diagram, and (c) is a measurement diagram. 35 …… Sub shaft, 37 …… Secondary pulley, 51 …… Ball bearing, 51a …… Inner race, 51b …… Outer race, 51c …… Ball.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-139047 (JP, A) Actually developed Shou 57-149323 (JP, U) How to select and use rolling bearings How to select rolling bearings How to use ”1st edition (1976-12-1) P. 274 Igamori Soga 2 “Miniature King Bearing” (Sho 36-12-30) Nikkan Kogyo Shimbun P. 120

Claims (1)

[Claims] 1. A belt type continuously variable transmission, wherein one pulley shaft is rotatably supported by a ball bearing disposed in the vicinity of the pulley to position the pulley and at the same time a gear mounted on the pulley shaft. In the configuration that simultaneously receives the thrust load and the radial load by the belt, the radius of curvature in each ball receiving portion of the inner race and the outer race of the ball bearing, the radius of curvature on the inner race side is 50.1 to 50.9% of the ball diameter, Set the radius of curvature on the outer race side to 50.1 to 51.9% of the ball diameter,
A pulley shaft support device for a continuously variable transmission, which is set to be smaller than a normal standard set value so as to approximate the curvature of a ball.