JP4250986B2 - Ball spline device for belt type continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ball spline device for a belt type continuously variable transmission suitable for sliding and guiding a movable pulley of a variable pulley.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known a ball spline device that slides and guides a movable pulley in a belt type continuously variable transmission while preventing rattling when a torsional load is applied (see Patent Document 1).
[0003]
This accommodates a plurality of balls across a pair of axial grooves provided opposite to each other on the outer peripheral surface of the rotating shaft integral with the fixed pulley and the inner peripheral surface of the boss portion integral with the movable pulley. In addition, the cross section of the axial groove is formed in a V shape, and the ball is supported in four-point contact by a pair of axial grooves.
[0004]
[Patent Document 1]
JP-A-6-300038 gazette
[Problems to be solved by the invention]
However, in the above conventional example, the torsional load acting on the movable pulley when the belt is driven is rigidly supported in the circumferential direction at two opposing points according to the load direction of the pair of axial grooves. There was a problem that wear was likely to occur when a load was applied.
[0006]
Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a ball spline device for a belt-type continuously variable transmission that can improve wear resistance.
[0007]
[Means for Solving the Problems]
The present invention extends over the axial groove formed on the inner peripheral surface of the boss portion of the movable pulley of the belt-type continuously variable transmission and the axial groove formed on the outer peripheral surface of the rotating shaft integral with the fixed pulley. A ball spline device that prevents a relative rotation of the movable pulley with respect to the rotation shaft by interposing a plurality of balls, each facing the pair of axial grooves as driving contact points for transmitting driving force to the pair of axial grooves. The two contact points that face each other at two points and are the driving contact points are arranged so as to be offset from each other by an equal distance from the center of the ball in the rotation axis direction of the ball at the time of shifting.
[0008]
【The invention's effect】
Therefore, in the present invention, the ball contacts the pair of axial grooves of the ball spline device of the belt-type continuously variable transmission at two opposing points serving as driving contact points for transmitting the driving force. The two contact points that face each other are offset from the center of the ball by the same distance in the direction of the rotation axis of the ball at the time of shifting, so that the load shared by each contact point is reduced. This reduces the wear resistance of the ball spline device, and even when shifting is performed during driving, the ball rolls without sliding on the driving contact point, and the rotating shaft and boss are shifted during shifting. The movable pulley can be moved relatively smoothly.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a ball spline device of a belt type continuously variable transmission according to the present invention will be described based on each embodiment.
[0010]
(First embodiment)
1 and 2 show a first embodiment of a ball spline device of a belt type continuously variable transmission to which the present invention is applied, and FIG. 1 shows the essentials of the belt type continuously variable transmission to which the ball spline device of the present invention is applied. FIG. 2 is an explanatory view showing a transmission path of driving force and rotational force at the time of deceleration in the ball spline device of the belt type continuously variable transmission, and FIG. 3 is an enlarged sectional view of the ball spline device of the first embodiment. It is. Here, first, the configuration of the belt-type continuously variable transmission and the applied ball spline device will be described with reference to FIG. 1, and then the ball spline device according to the first embodiment will be described with reference to FIG.
[0011]
In FIG. 1, fixed pulleys 6 and 8 are fixedly provided on a drive shaft 2 and a driven shaft 4 (hereinafter, both are simply referred to as a rotation shaft). Opposing to the fixed pulleys 6 and 8, movable pulleys 10 and 12 are provided so as to be able to slide in the axial direction along the rotation shafts 2 and 4. The movable pulleys 10 and 12 are fitted to the rotary shafts 2 and 4 at the boss portions 14 and 16, but the axial grooves 18 and 20 formed on the inner peripheral surfaces of the boss portions 14 and 16 of the movable pulleys 10 and 12. A plurality of balls 26 are interposed across the axial grooves 22 and 24 formed on the outer peripheral surfaces of the rotary shafts 2 and 4, respectively, whereby the rotary shafts 2 and 4 of the movable pulleys 10 and 12 are interposed. Relative rotation with respect to is prevented.
[0012]
The axial groove 18 (20) and the axial groove 22 (24) and the ball 26 constitute ball spline devices 25 and 27. In the vicinity of the end portions of the axial grooves 18 and 20 and in the vicinity of the end portions of the axial grooves 22 and 24, a retaining ring 28 of the ball 26 is disposed so as to be fitted into the circumferential groove.
[0013]
A conical surface having a very large apex angle is formed on the end surfaces of the fixed pulleys 6 and 8 and the movable pulleys 10 and 12 facing each other, and V grooves 30 and 32 are formed between the conical surfaces. The combination of the fixed pulley 6 and the movable pulley 10 is referred to as a drive transmission pulley 34, and the combination of the fixed pulley 8 and the movable pulley 12 is referred to as a driven transmission pulley 36.
[0014]
A metal belt 38 is wound around the drive transmission pulley 34 and the driven transmission pulley 36. The metal belt 38 is composed of a pair of flexible hoops 40 in which a plurality of metal rings are overlapped, and a large number of metal elements 42 attached thereto, and the elements 42 are the hoops 40. So that the rotational torque of the drive transmission pulley 34 is transmitted to the driven transmission pulley 36.
[0015]
A piston 44 is fixed to the drive shaft 2, and an outer peripheral surface of the piston 44 is fitted to an inner peripheral surface of a housing 46 that is fixed to the movable pulley 10 by press fitting, so that the piston 44, the drive shaft 2, and the movable pulley 10 are fitted. A drive hydraulic chamber 48 is formed by the housing 46. The drive hydraulic chamber 48 is connected to an external hydraulic source via an oil passage 50 formed in the drive shaft 2. On the other hand, a piston 52 is fixed to the driven shaft 4, and an outer peripheral surface of the piston 52 is fitted to an inner peripheral surface of a housing 54 fixed by press-fitting to the movable pulley 12, so that the piston 52, the driven shaft 4, and the movable pulley are fitted. A driven hydraulic chamber 56 is formed by 12 and the housing 54. The driven hydraulic chamber 56 is connected to an external hydraulic source via an oil passage 58 formed in the driven shaft 4.
[0016]
The movable pulley 12 of the driven transmission pulley 36 receives the hydraulic pressure in the driven hydraulic chamber 56. In this case, the pressure receiving area is smaller than the pressure receiving area of the movable pulley 10 of the drive transmission pulley 34. Therefore, when the hydraulic oil amount in the drive hydraulic chamber 48 of the drive transmission pulley 34 is adjusted to change the width of the V groove 30 of the drive transmission pulley 34, the movable pulley of the driven transmission pulley 36 follows this. 12 is moved in the axial direction, the amount of hydraulic oil in the driven hydraulic chamber 56 is increased or decreased, and the width of the V groove 32 of the driven transmission pulley 36 is adapted to the width of the V groove 30 of the drive transmission pulley 34. Will change. That is, the gear ratio, that is, the ratio of the rotational speeds of the drive transmission pulley 34 and the driven transmission pulley 36 is changed by controlling the amount of hydraulic oil in the drive hydraulic chamber 48 on the drive transmission pulley 34 side. The tension of the V belt 38 is kept at an optimum value by controlling the hydraulic pressure in the driven hydraulic chamber 56 of the driven transmission pulley 36.
[0017]
As described above, the ball spline devices 25 and 27 are arranged on the drive transmission pulley 34 and the driven transmission pulley 36, and as shown in FIG. And between the rotary shafts 2 and 4. That is, at the time of driving, the ball spline device 25 of the drive speed change pulley 34 transmits the driving force of the drive shaft 2 to the movable pulley 10 (via the boss portion 14) as indicated by an arrow through the ball 26, The ball spline device 27 of the driven transmission pulley 36 transmits the driving force from the movable pulley 12 (via the boss portion 16) to the driven shaft 4 through the ball 26 as indicated by an arrow. At the time of deceleration, the ball spline device 27 of the driven transmission pulley 36 transmits the rotational force at the time of deceleration from the driven shaft 4 to the movable pulley 12 through the ball 26 as indicated by the arrow, and the drive transmission pulley 34 The ball spline device 25 transmits the rotational force from the movable pulley 10 to the drive shaft 2 through the ball 26 as indicated by an arrow.
[0018]
The ball spline devices 25 and 27 are arranged between the ball 26 and the axial grooves 22 and 24 of the rotary shafts 2 and 4 and the shafts of the ball 26 and the boss portions 14 and 18 in order to constitute the transmission path of the driving force. In order to form a driving contact point between the directional grooves 18 and 20 and to constitute a transmission path for the rotational force during deceleration, the ball 26 and the axial grooves 22 and 24 of the rotary shafts 2 and 4 A deceleration contact point is formed between the ball 26 and the axial grooves 18 and 20 of the boss portions 14 and 16. These driving contact points transmit the driving force, and also serve as rolling surfaces for the axial grooves 18 to 24 of the balls 26 of the ball spline devices 25 and 27 accompanying the movement of the movable pulleys 10 and 12 accompanying the speed change during driving. In addition to transmitting the rotational force at the time of deceleration, the deceleration contact point is formed by the axial grooves 18 to 18 of the balls 26 of the ball spline devices 25 and 27 accompanying the movement of the movable pulleys 10 and 12 accompanying the speed change at the time of deceleration. A rolling surface for 24 is formed.
[0019]
The drive contact point and the deceleration contact point are arranged as shown in FIG. 3 in the ball spline device 25 of the drive transmission pulley 34. That is, the ball 26 comes into contact with the axial groove 22 of the rotating shaft 2 at each of the three points of the drive contact points A1 and B1 and the deceleration contact point C1, and the ball 26 drives the axial groove 18 of the boss portion 14. The contact points A2 and B2 and the deceleration contact point C2 are in contact with each other, and the contact points are 6 points in total.
[0020]
The drive contact points A1 and A2 and the drive contact points B1 and B2 are in line-symmetric positions with respect to the ball center O, respectively, and so on from the center O of the ball 26 in the direction of the rotation axis X of the ball 26 at the time of shifting. It is arranged with a distance offset. In this case, the rotation axis X of the ball 26 can be expressed as a straight line X including the ball center O at equal distances from the drive contact points A1, B1 and A2, B2. That is, the rolling contact surfaces SA and SB formed by the driving contact points A1 and A2 and the driving contact points B1 and B2 forming a pair do not include the ball center O, and the like from the ball center O to the ball rotation axis X direction, etc. Offset by distance. For this reason, when the boss portion 14 is moved in the axial direction at the time of shifting, the rotation distance of the ball 26 formed by the drive contact points A1 and A2 and the rotation distance of the ball 26 formed by the drive contact points B1 and B2 And there is no slip between the ball 26 and the axial grooves 18 and 22, and the ball 26 smoothly contacts the driving contact points A1, A2, B1, and B2.
[0021]
The decelerating contact points C1 and C2 are provided so that the rolling contact surface SC at the time of shifting intersects with the rolling contact surfaces SA and SB formed by the drive contact points A1, A2, B1 and B2, and within the rolling contact surface SC. Are configured to include the ball center O.
[0022]
The axial grooves 18 and 22 of the drive shaft 2 and the boss portion 14 have three arcs 18A and 18B, respectively, to constitute the drive contact points A1, A2, B1 and B2 and the deceleration contact points C1 and C2. 18C and 22A, 22B, 22C. That is, arcs 18A, 18B and 22A, 22B formed to constitute the drive contact points A1, A2, B1, B2 and arcs 18C, 22C formed to configure the deceleration contact points C1, C2 are provided. Arcs 18A, 18B and 22A, 22B formed to constitute the drive contact points A1, A2, B1, B2 are the outer peripheral extensions of the virtual rolling surface SAB formed by the drive contact points A1, A2, B1, B2. The joints between the arcs 18A, 18B and 22A, 22B exist on the upper side.
[0023]
Also in the ball spline device 27 of the driven transmission pulley 36, although not shown, two sets of driving contact points and one set of deceleration contact points are arranged. The driving contact point is different from that shown in FIG. 3 so that driving force is transmitted from the axial groove 20 of the boss portion 16 of the movable pulley 12 to the axial groove 24 of the driven shaft 4 via the ball 26. Similarly, the deceleration contact point is formed symmetrically with the line shown in FIG. 3 (vertical line including the ball center in the figure).
[0024]
In the ball spline device 25 (27) of the belt type continuously variable transmission having the above-described configuration, the drive force from the drive shaft 2 (movable pulley 12) of the drive transmission pulley 34 (36) is transmitted via the drive contact points A1 and B1. It is transmitted to the ball 26 and transmitted from the ball 26 to the boss portion 14 (driven shaft 4) of the movable pulley 10 via the drive contact points A2 and B2. At this time, since there are two sets of transmission paths, that is, the set of drive contact points A1 and A2 and the set of drive contact points B1 and B2, the load shared by each contact point is reduced, and the ball spline device 25 The wear resistance of (27) can be improved.
[0025]
In addition, even when shifting is performed during driving, the set of the driving contact points A1 and A2 and the set of the driving contact points B1 and B2 are equally offset from the ball center O. The ball 26 rolls without slipping on the drive contact point, and the drive shaft 2 (driven shaft 4), the boss portion 14 (16), and the movable pulley 10 (12) smoothly move relative to each other at the time of shifting. Can do.
[0026]
Since the deceleration contact points C1 and C2 are formed at two opposing points including the ball center O, during high speed driving where a high load is applied to the drive contact points A1, A2 and B1, B2, Sliding with the deceleration contact points C1 and C2 with respect to the rotation of the ball 26 can be reduced, and sliding resistance that does not contribute to driving force transmission can be reduced. Note that the sliding at the deceleration contact points C1 and C2 during driving can be ignored because the load applied in the deceleration direction is minute.
[0027]
In the present embodiment, the following effects can be achieved.
[0028]
(A) The ball 26 opposed to the pair of axial grooves 18, 22, and 20, 24 of the ball spline device 25, 27 of the belt type continuously variable transmission is opposed to each other as a driving contact point for transmitting a driving force. The two contact points facing each other at the point and serving as the driving contact point are arranged so as to be offset from the center of the ball 26 by an equal distance in the direction of the rotation axis X of the ball 26 at the time of shifting. Therefore, the load shared by each contact point can be reduced, the wear resistance of the ball spline devices 25 and 27 can be improved, and the ball 26 can move to the drive contact point even when shifting is performed during driving. It rolls without sliding on the top, and the rotary shafts 2 and 4, the boss portions 14 and 16, and the movable pulleys 10 and 12 can be smoothly moved relative to each other during shifting.
[0029]
(A) Since the ball 26 contacts the pair of axial grooves 18, 22, and 20, 24 at one point facing each other as a decelerating contact point for transmitting the rotational force during deceleration, a high load is applied. At the time of acceleration applied to the driving contact point, sliding with the deceleration contact point with respect to the rotation of the ball 26 at the time of shifting can be reduced, and sliding resistance that does not contribute to driving force transmission can be reduced. Note that the sliding at the deceleration contact point during driving is negligible because the load applied in the deceleration direction is very small.
[0030]
(Second Embodiment)
4 to 6 show a ball spline device of a belt type continuously variable transmission according to a second embodiment of the present invention, FIG. 4 is an enlarged sectional view of the ball spline device of the second embodiment, and FIG. FIG. 6 is an explanatory diagram showing a specific implementation point. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and the description is simplified or abbreviate | omitted. In the spline device of the belt type continuously variable transmission according to the present embodiment, the arrangement of the deceleration contact points is different from that of the first embodiment.
[0031]
In FIG. 4, the deceleration contact points C1 and C2 are straight lines SA and SB (which become rolling surfaces) where the straight line SC (which becomes the rolling surface) connecting the two points connects the driving contact points A1, A2, B1 and B2. It arrange | positions so that it may orthogonally cross. With this configuration, when the high load is applied to the drive contact points A1, A2, B1, and B2, the contact with the deceleration contact points C1 and C2 with respect to the rotation of the ball 26 at the time of shifting is reduced. However, the sliding resistance of the ball 26 at the time of a shift that does not contribute to the driving force transmission can be further reduced because the rotational contact can be made only around the straight line SC connecting the deceleration contact points C1 and C2. Note that the sliding at the deceleration contact points C1 and C2 during driving can be ignored because the load applied in the deceleration direction is minute.
[0032]
In the present embodiment, the straight lines SA and SB connecting the driving contact points A1 and A2 and B1 and B2 extend from the axis O1 of the rotating shaft so as to be in contact with the surface of the ball 26, and the straight lines A1-O1 or A2-O1 Are configured to be orthogonal. That is, as shown in FIG. 5, when the intersection of the virtual rolling surface SAB of the driving contact points with the surface of the ball 26 is A, ∠O−A−O1 = 90 °, and the shaft radius is An angle that can be expressed as θ = cos ⁻¹ (r / R) where R, the ball radius is r, and the angle between the straight line connecting the axis center O1 and the ball center O and the virtual sliding surface SAB by the driving contact point is θ. Set to. By setting in this way, the driving force of the rotating shaft 2 can be transmitted to the boss portion 14 without generating a radial component force. In the driven transmission pulley 36, the rotational force of the boss portion 16 is transmitted. 100% can be transmitted to the driven shaft 4. Such a configuration is easily achieved by forming the axial grooves 18, 22 and 20, 24 of the rotating shafts 2 and 4 and the boss portions 14 and 16 asymmetrically on the left and right, as shown in FIG. be able to.
[0033]
In the present embodiment, in addition to the effects (a) and (b) in the first embodiment, the following effects can be achieved.
[0034]
(C) Since the straight line SC connecting the deceleration contact points C1 and C2 is arranged so as to be orthogonal to the centers of the straight lines SA and SB connecting the drive contact points A1 and A2 and B1 and B2, a high load is applied to the drive contact point. During acceleration driving applied to A1, A2 and B1, B2, the contact with the deceleration contact points C1, C2 with respect to the rotation of the ball 26 at the time of shifting is about the straight line SC connecting the deceleration contact points C1, C2 with each other. The sliding resistance of the ball 26 at the time of shifting which does not contribute to driving force transmission can be further reduced. The sliding at the deceleration contact points C1 and C2 during driving can be ignored because the load applied in the deceleration direction is very small.
[0035]
(D) The straight lines SA and SB connecting the driving contact points A1, A2 and B1, B2 are orthogonal to the straight lines O-A1 and O-B1 contacting the surface of the ball 26 from the center O of the rotating shafts 2 and 4. Therefore, all of the driving force of the rotating shafts 2 and 4 can be transmitted to the boss portion 14 without generating a radial component force. In the driven transmission pulley 36, the rotating force of the boss portion 16 is transmitted to the driven shaft 4 Can communicate everything.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part of a ball spline device for a belt type continuously variable transmission according to the present invention.
FIG. 2 is an explanatory diagram showing a transmission path of driving force and rotational force at the time of deceleration in a ball spline device of a belt type continuously variable transmission.
FIG. 3 is an enlarged cross-sectional view of the ball spline device of the belt type continuously variable transmission according to the first embodiment of the present invention.
FIG. 4 is an enlarged sectional view of a ball spline device of a belt type continuously variable transmission according to a second embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating a driving force transmission state according to the second embodiment.
FIG. 6 is an explanatory diagram showing a specific implementation point of the second embodiment.
[Explanation of symbols]
A1, A2, B1, B2 Drive contact point C1, C2 Deceleration contact point 2 Drive shaft (rotary shaft)
4 Driven shaft (rotating shaft)
6, 8 Fixed pulleys 10, 12 Movable pulleys 14, 16 Boss portions 18, 20, 22, 24 Axial grooves 25, 27 Ball spline device 26 Ball 34 Drive transmission pulley 36 Driven transmission pulley 38 Metal belt

Claims (4)

A movable pulley with a plurality of balls interposed between an axial groove formed on the inner peripheral surface of the boss portion of the movable pulley and an axial groove formed on the outer peripheral surface of the rotating shaft integral with the fixed pulley. A ball spline device for a belt-type continuously variable transmission that prevents relative rotation with respect to the rotation axis of the belt,
The ball contacts the pair of axial grooves at two opposing points serving as driving contact points for transmitting driving force,
The belt type continuously variable transmission characterized in that the two contact points facing each other as the driving contact points are offset from each other by an equal distance from the center of the ball in the direction of the rotation axis of the ball during shifting. Machine ball spline device. 2. The belt-type continuously variable belt according to claim 1, wherein the balls are in contact with the pair of axial grooves at one point facing each other as a deceleration contact point that transmits a rotational force during deceleration. Ball spline device for transmission. 3. The ball spline device for a belt-type continuously variable transmission according to claim 2, wherein the straight line connecting the deceleration contact points is disposed so as to be orthogonal to the center of the straight line connecting the drive contact points. The belt type according to any one of claims 1 to 3, wherein a straight line connecting the driving contact points is orthogonal to a straight line contacting the ball surface from the center of the rotation axis. Ball spline device for continuously variable transmission.

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