JP4096510B2 - Ball screw type feeder and continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a feed device used for axially displacing a pulley in a continuously variable transmission and a continuously variable transmission including the same.
[0002]
[Prior art]
Conventionally, as a feeding device, a plurality of balls interposed between the spiral grooves of the inner member and the outer member, and a circulator tube that circulates the balls from one side of the spiral groove of each of the inner member and the outer member to the other side. It consists of and.
[0003]
[Problems to be solved by the invention]
However, the conventional feeding device using the circulator tube is large in size and heavy.
[0004]
In view of this, a ball screw type feeding device with a non-circulating cage that has a cage for holding the ball and does not circulate the ball has been proposed.
[0005]
In this ball screw type feeding device with a cage, a stopper that engages the cage in the axial direction is fixed to the inner member or the outer member so that the cage does not come out in the axial direction. The dimensions were increased.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a feeding device that can be further reduced in size and a continuously variable transmission including the same.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the feeding device of the invention of claim 1 includes an inner member in which a spiral groove track is formed on the outer periphery,
An outer member having a spiral groove track on the inner periphery;
A plurality of balls interposed between the two spiral groove tracks,
A ball screw type feeding device comprising an annular retainer formed with a plurality of pockets for holding the plurality of balls;
A first stopper that restricts the axial movement of the cage is provided at one end of the spiral groove track of the inner member in the circumferential direction with respect to the cage.
Engages in a circumferential direction relative to the cage to the other end of the spiral groove track of said outer member, set the second stopper for restricting the axial movement of the retainer,
When the inner member and the outer member move relative to each other in the axial direction to reach the shortest state, the first stopper is engaged with one end surface in the circumferential direction of the cage in the circumferential direction and the second stopper. The stopper is engaged with the other end surface in the circumferential direction of the cage in the circumferential direction to stop shortening, and the movement of the cage in the axial direction is restricted.
[0008]
In the first aspect of the invention, the stoppers provided on the inner member and the outer member engage with the retainer in the circumferential direction to restrict the axial movement of the retainer. Thus, compared with the case of engaging in the axial direction, the force applied to the stopper can be reduced, and the stopper can be miniaturized. Further, since the stopper may be disposed so as to engage with the cage in the circumferential direction, the axial dimension can be reduced.
[0009]
Moreover, in this invention of Claim 1 , since the two stoppers are provided separately for the inner member and the outer member, the stopper arrangement space can be shared by the inner member and the outer member. Therefore, the overall axial dimension can be reduced as compared with the case where two stoppers are provided on one of the inner member and the outer member.
[0010]
Further, the feeding device of one embodiment, the stopper is than the circumferential direction of the section modulus of the case where the cross-sectional shape that is circular, Ru sectional shape der like section modulus in the circumferential direction is increased.
[0011]
In this embodiment , the stopper has a cross-sectional shape (for example, an ellipse or a rectangle) in which the cross-sectional modulus in the circumferential direction is larger than the cross-sectional modulus in the circumferential direction when the cross-sectional shape is circular. The axial dimension can be reduced while maintaining the strength.
[0012]
Further, the feeding device of one embodiment, the stopper surface which engages in a circumferential direction relative to the retainer is not not been chamfered.
[0013]
In this embodiment , since the stopper is not chamfered in the circumferential direction with respect to the cage, the circumferential engagement surface of the stopper is directly engaged with the circumferential end surface of the cage. The rotation of the cage can be stopped reliably. In addition, since an oblique force is not applied to the stopper, the stopper can be prevented from coming off.
[0014]
The invention of claim 3 is the feeding device according to claim 1,
The stopper is driven into a hole formed in the spiral groove track of the inner member or the spiral groove track of the outer member, and a protrusion formed on the outer periphery bites into the hole.
[0015]
In the invention of claim 3 , since the protrusion formed on the outer periphery of the stopper is caused to bite into the hole formed in the spiral groove track, it is easy to press-fit, and the stopper is firmly fixed to the spiral groove track. it can. Moreover, even if the tolerance of the hole can be relaxed and the raceway surface is quenched, the protrusions are plastically deformed, so that the press-fitting becomes easy.
[0016]
According to a fourth aspect of the present invention, a continuously variable transmission includes the feeding device according to any one of the first to third aspects.
[0017]
In the fourth aspect of the invention, a compact continuously variable transmission can be realized by including the feeding device according to any one of the first to third aspects.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0019]
FIG. 1 shows a cross section of an embodiment of the feeding device of the present invention. This embodiment is arranged between an inner cylinder member 1 having a spiral groove track 1A formed on the outer periphery, an outer cylinder member 2 having a spiral groove track 2A formed on the inner periphery, and the spiral groove tracks 1A and 2A. And a plurality of balls 5 held by the cage 3.
[0020]
A through hole 6 is formed at one end on the base side of the spiral groove track 2A of the outer cylinder member 2, and a stopper pin 7 is driven into the through hole 6 from the outer peripheral side. Further, a through hole 8 is formed at one end of the spiral groove track 1A of the inner cylinder member 1 on the base side, and a stopper pin 10 is driven into the through hole 8 from the inner peripheral side. FIG. 3 shows a state where the stopper pin 10 driven from the inner peripheral side of the inner cylinder member 1 protrudes into the spiral groove track 1A.
[0021]
As schematically shown in FIG. 2, the stopper pin 10 driven into the inner cylinder member 1 engages with the circumferential end face 3 </ b> A of the cage 3 in the circumferential direction. Further, the stopper pin 7 driven into the outer cylinder member 2 is engaged with the other circumferential end face 3B of the cage 3 in the circumferential direction.
[0022]
As shown in FIG. 2, the cage 3 has a plurality of slit-like pockets 11 at predetermined intervals in the circumferential direction so as to hold the balls 5 at substantially equal intervals along the spiral groove tracks 1A and 2A. Have. The pocket 11 holds three balls 5 each. As shown in FIG. 2, a slit-like pocket 12 shorter than the slit-like pocket 11 is formed in the row where the end faces 3A, 3B with which the stopper pins 10, 7 are engaged are formed. Two balls 5 are held.
[0023]
In this embodiment, the inner cylinder member 1 is rotated counterclockwise in the direction of arrow Z with respect to the outer cylinder member 2 from the shortest state shown in FIG. The cylindrical member 2 can be moved linearly in the axial direction of the arrow Y and extended. Further, by rotating the inner cylinder member 1 in the clockwise direction opposite to the arrow Z, the cage 3, the ball 5 and the outer cylinder member 2 can be linearly moved in the opposite direction of the arrow Y and contracted together. . Here, when the shortest state is reached, the stopper pin 10 is engaged with the end surface 3A of the retainer 3 in the circumferential direction, the stopper pin 7 is engaged with the end surface 3B, and the inner cylinder member 1 and the retainer 3, Relative rotation between the ball 5 and the outer cylinder member 2 stops, and further contraction stops.
[0024]
Thus, in this embodiment, the stopper pin 10 is engaged with the end surface 3A of the retainer 3 in the circumferential direction, so that the retainer 3 passes over the stopper pin 10 toward the base 1B side with respect to the inner cylinder member 1. Prevent moving. Further, the stopper pin 7 is engaged with the end surface 3B in the circumferential direction, thereby preventing the retainer 3 from moving beyond the stopper pin 7 toward the base 2B side with respect to the outer cylinder member 2.
[0025]
Therefore, in this embodiment, compared with the case where the stopper is engaged with the cage in the axial direction, the force applied to the stopper pins 7 and 10 can be reduced, and the stopper pins 7 and 10 can be downsized. Further, since the stopper pins 7 and 10 may be arranged so as to engage with the cage 3 in the circumferential direction, the arrangement space in the axial direction can be reduced and the axial dimension can be reduced.
[0026]
In this embodiment, since the two stopper pins 7 and 10 are provided separately for the inner member 1 and the outer member 2, the stopper arrangement space can be shared by the inner member 1 and the outer member 2. Therefore, compared with the case where two stopper pins are provided on one of the inner member 1 or the outer member 2, the overall axial dimension can be reduced. Therefore, the continuously variable transmission can be made compact by providing the feeding device of this embodiment.
[0027]
In this embodiment, the stopper pins 7 and 10 are not chamfered at the corners of the peripheral surfaces 7A and 10A and the end surfaces 7B and 10B that are engaged with the cage 3 in the circumferential direction. Therefore, as shown in FIG. 5 (B), the circumferential engagement surfaces 7A, 10A of the stopper pins 7, 10 receive force in the direction perpendicular to the axis from the circumferential end surfaces 3B, 3A of the cage 3, 3 can be stopped reliably. Further, as shown in FIG. 5A, when the corner of the stopper pin 100 is chamfered, when the end surface of the retainer 3 comes into contact with the chamfered corner surface 101, the stopper pin 100 is inclined. There is a possibility that the stopper pin 100 may come off due to the force applied. On the other hand, according to this embodiment, since the stopper pins 7 and 10 receive the force in the direction perpendicular to the axis from the cage 3, it is possible to prevent the stopper pins from coming out.
[0028]
In the above embodiment, the stopper pins 7 and 10 are formed in a circular column shape having a circular cross section, but the cross section may be an elliptical shape having a major axis in the rotation direction and a minor axis in the axial direction. In this case, the section modulus in the circumferential direction can be increased and the axial dimension can be reduced as compared with a circular section.
[0029]
Further, instead of the stopper pins 7 and 10, as shown in FIGS. 4A and 4B, a stopper pin 42 with a protrusion having a protrusion 41 having a triangular cross section protruding radially on the outer periphery of the press-fitted portion is provided. It may be adopted. In this case, since the protrusion 41 bites into the holes 6 and 8, the fixing to the spiral groove tracks 2A and 1A can be firmly performed, and the press-fitting becomes easy. Moreover, even if the tolerances of the holes 6 and 8 can be relaxed and the raceway surface is quenched, the protrusion 41 is plastically deformed, so that press fitting is easy.
[0030]
In the above embodiment, the inner member is the inner cylinder member 1, but the inner member may be a solid shaft member. Moreover, in the said embodiment, although the stopper pin was provided in the inner cylinder member 1 and the outer cylinder member, when a stopper pin is provided in the both ends of the axial direction of the spiral groove track | orbit of an outer cylinder member, it becomes a reference example. Further, when stopper pins are provided at both ends of the spiral groove track of the inner cylinder member in the axial direction, this is a reference example. Moreover, in the said embodiment, although the pockets 11 and 12 of the holder | retainer 3 were made into the slit shape extended in an axial direction, it is good also as a circular pocket which hold | maintains the ball | bowl 5 one by one.
[0031]
【The invention's effect】
As apparent from the above, in the ball screw type feeding device according to the first aspect of the present invention, the stopper provided on the inner member and the outer member is engaged with the retainer in the circumferential direction so that the axial direction of the retainer is Therefore, as compared with the case where the stopper is engaged with the cage in the axial direction, the force applied to the stopper can be reduced and the stopper can be downsized. Further, since the stopper may be disposed so as to engage with the cage in the circumferential direction, the axial dimension can be reduced.
[0032]
The invention of claim 1, the two stopper, so are provided separately in the inner and outer members may share the stopper arrangement space between the inner and outer members. Therefore, the overall axial dimension can be reduced as compared with the case where two stoppers are provided on one of the inner member and the outer member.
[0033]
In one embodiment , the stopper has a cross-sectional shape (for example, an ellipse or a rectangle) in which the cross-sectional modulus in the circumferential direction is larger than the cross-sectional modulus in the circumferential direction when the cross-sectional shape is circular. The axial dimension can be reduced while maintaining the stopper strength.
[0034]
In one embodiment , since the stopper is not chamfered in the circumferential direction of the surface that engages the retainer, the circumferential engagement surface of the stopper is straight with respect to the circumferential end surface of the retainer. Engagement is possible and rotation of the cage can be reliably stopped. In addition, since a force in an oblique direction is not applied to the stopper, the stopper can be prevented from coming off.
[0035]
Further, in the invention of claim 3 , since the protrusion formed on the outer periphery of the stopper is bitten into the hole formed in the spiral groove track, the press-fitting becomes easy and the stopper is firmly fixed to the spiral groove track. Can be. Moreover, even if the tolerance of the hole can be relaxed and the raceway surface is quenched, the protrusions are plastically deformed, so that the press-fitting becomes easy.
[0036]
A continuously variable transmission according to a fourth aspect of the invention includes the feeding device according to any one of the first to third aspects, whereby a compact continuously variable transmission can be realized.
[Brief description of the drawings]
FIG. 1 is a half sectional view of an embodiment of a ball screw type feeding device of the present invention.
FIG. 2 is a schematic diagram showing a fitting state of an inner cylinder member, a cage, a ball, and a stopper pin according to the embodiment.
FIG. 3 is a schematic view showing a state where a stopper pin is driven into the inner cylinder member of the embodiment.
FIG. 4A is an end view of a dowel pin as a modified example of the stopper pin of the above embodiment, and FIG. 4B is a cross-sectional view showing a state where the dowel pin is driven.
FIG. 5A is a view showing a state in which the circumferential end surface of the cage is in contact with a stopper pin having a chamfered corner, and FIG. It is a figure which shows a mode that the circumferential direction end surface of a holder | retainer is contacting the stopper pin.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Inner cylinder member, 1A ... Spiral groove track, 1B ... Base, 2 ... Outer cylinder member,
2A ... spiral groove track, 3 ... cage, 3A, 3B ... end face, 5 ... ball,
6, 8 ... through hole, 7, 10 ... stopper pin, 7A, 10A ... peripheral surface,
7B, 10B ... end face, 11, 12 ... slit pocket, 41 ... projection,
42: Stopper pin with protrusion.

Claims (4)

An inner member formed with a spiral groove track on the outer periphery;
An outer member having a spiral groove track on the inner periphery;
A plurality of balls interposed between the two spiral groove tracks,
A ball screw type feeding device including an annular cage formed with a plurality of pockets for holding the plurality of balls;
A first stopper that restricts the axial movement of the cage is provided at one end of the spiral groove track of the inner member in the circumferential direction with respect to the cage.
Engages in a circumferential direction relative to the cage to the other end of the spiral groove track of said outer member, set the second stopper for restricting the axial movement of the retainer,
When the inner member and the outer member move relative to each other in the axial direction to reach the shortest state, the first stopper engages with one end surface in the circumferential direction of the retainer in the circumferential direction and the second stopper. The stopper is engaged with the other end surface in the circumferential direction of the cage in the circumferential direction to stop shortening, and the feeding device is characterized in that the axial movement of the cage is restricted . The feeding device according to claim 1,
The feeding device according to claim 1 , wherein the first and second stoppers have an elliptical cross section having a major axis in the circumferential direction and a minor axis in the axial direction. The feeding device according to claim 1,
The feeding device according to claim 1, wherein the stopper is driven into a hole formed in the spiral groove track of the inner member or the spiral groove track of the outer member, and a protrusion formed on the outer periphery bites into the hole.   A continuously variable transmission comprising the feeding device according to any one of claims 1 to 3.

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