Sensor arrangement structure

The sensor arrangement structure includes a pulley that rotates about a rotation axis; and a sensor that detects rotation of the pulley. The pulley includes a fixed pulley, a movable pulley that can be displaced relative to the fixed pulley in a direction of the rotation axis, and a plunger defining an oil chamber on a back of the movable pulley. The plunger is provided with a detection target portion in a region that can be visually recognized from the direction of the rotation axis, and the sensor is provided on a support portion that rotatably supports the fixed pulley in a direction along the rotation axis and faces the region in which the detection target portion is provided.

TECHNICAL FIELD

The present invention relates to a sensor arrangement structure in a continuously variable transmission.

BACKGROUND ART

Patent Literature 1 discloses a belt continuously variable transmission.

CITATION LIST

Patent Literature

Patent Literature 1: JP 2012-047324 A

SUMMARY OF INVENTION

The belt continuously variable transmission in Patent Literature 1 includes a sensor that detects a rotation speed of a pulley. A movable pulley of the pulley includes a plunger.

The sensor is provided in a direction perpendicular to a rotation axis of the pulley. A detection portion of the sensor faces an outer periphery of the plunger from a radially outer side of the rotation axis.

The movable pulley can be displaced in a direction of the rotation axis. Therefore, the sensor avoids interference with components of the movable pulley.

Accordingly, there are restrictions on where the sensor can be provided in the belt continuously variable transmission. Hence, it is required to further increase a degree of freedom in providing the sensor.

A sensor arrangement structure according to one aspect of the present invention includes:a pulley that rotates about a rotation axis; anda sensor that detects rotation of the pulley, in whichthe pulley includesa fixed pulley,a movable pulley that can be displaced relative to the fixed pulley in a direction of the rotation axis, anda plunger that defines an oil chamber on a back of the movable pulley,the plunger is provided with a detection target portion in a region that can be visually recognized from the direction of the rotation axis, andthe sensor is provided on a support portion that rotatably supports the fixed pulley in a direction along the rotation axis and faces the region where the detection target portion is provided.

According to the aspect of the present invention, it is possible to increase the degree of freedom in providing the sensor.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an example in which a sensor arrangement structure according to one aspect of the present invention is applied to a belt continuously variable transmission1for a vehicle will be described.

FIG.1shows a configuration of main parts of the continuously variable transmission1.

FIG.2is an enlarged view showing surroundings of a primary pulley3of the continuously variable transmission1.

As shown inFIG.1, in the belt continuously variable transmission1, a rotational driving force of an engine (not shown) is input to a forward and reverse switching mechanism5via a torque converter (not shown).

The forward and reverse switching mechanism5includes a planetary gear set6, a forward clutch51, and a reverse brake52.

In the forward and reverse switching mechanism5, when the forward clutch51is engaged, rotation received from the torque converter is output to a variator2in forward rotation. When the reverse brake52is engaged, the rotation received from the torque converter is output to the variator2in reverse rotation.

The variator2includes a pair of pulleys (a primary pulley3and a secondary pulley4) and a belt V (an endless annular member) wound around the pair of pulleys.

In the variator2, by changing winding radii of the belt V around the pair of pulleys (the primary pulley3and the secondary pulley4), a speed of rotation received from the forward and reverse switching mechanism5is changed and the rotation is output to a final speed reduction mechanism (not shown).

As shown inFIG.2, the primary pulley3includes a fixed pulley31and a movable pulley32.

The fixed pulley31includes a shaft portion311arranged along a rotation axis X1and a sheave portion312extending radially outward from an outer periphery of the shaft portion311.

Bearings34A and34B are externally fitted and fixed to one end311aand the other end311bof the shaft portion311in a longitudinal direction, respectively.

The one end311aof the shaft portion311is rotatably supported by a support hole15of a side cover13via the bearing34A. The other end311bof the shaft portion311is rotatably supported by a support portion101of a transmission case10via the bearing34B.

A coupling member641included in a carrier64of the planetary gear set6(seeFIG.1) is coupled to the other end311bof the shaft portion311in a relatively non-rotatable manner.

The movable pulley32includes an annular base portion321externally fitted onto the shaft portion311of the fixed pulley31and a sheave portion322extending radially outward from an outer periphery of the annular base portion321.

The annular base portion321of the movable pulley32includes a large diameter portion321aon the sheave portion322side and a small diameter portion321bhaving an outer diameter smaller than that of the large diameter portion321a. A thickness of the annular base portion321in a radial direction of the rotation axis X1increases toward the sheave portion322.

The annular base portion321of the movable pulley32is spline-fitted to the outer periphery of the shaft portion311. The movable pulley32is movable in an axial direction of the shaft portion311(a direction of the rotation axis X1) in a state where relative rotation with respect to the fixed pulley31is restricted.

The sheave portion312of the fixed pulley31and the sheave portion322of the movable pulley32face each other with an interval therebetween in the direction of the rotation axis X1.

In the primary pulley3, a V-shaped groove33around which the belt V is wound is formed between a sheave surface312aof the fixed pulley31and a sheave surface322aof the movable pulley32.

On an outer diameter side of the sheave portion322, a cylinder portion323having a cylindrical shape is provided on a back322b(a pressure receiving surface) opposite to the sheave surface322a.

The cylinder portion323is provided in a direction along the rotation axis X1. The cylinder portion323is formed at a length L1in a direction away from the sheave portion322.

Here, a support wall portion131of the side cover13is located closer to the movable pulley32(right side in the drawing) than the bearing34A. Furthermore, the support wall portion131extends radially outward of the rotation axis X1on an outer diameter side relative to the bearing34A. The support wall portion131serves as a support portion for a sensor120, which will be described later.

As shown inFIG.2, a tip end323aof the cylinder portion323of the movable pulley32faces an inner periphery131aof the support wall portion131from the direction of the rotation axis X1. When the sheave portion322of the movable pulley32is arranged at a farthest position from the sheave portion312of the fixed pulley31, a gap is secured between the tip end323aand the inner periphery131a. In this state, the tip end323aof the cylinder portion323is located near the support wall portion131of the side cover13.

The cylinder portion323is a cylindrical wall portion that surrounds the rotation axis X1with an interval therebetween. An outer periphery70aof the plunger7is located inside the cylinder portion323. The plunger7defines an oil chamber R1between the plunger7and the back322bof the sheave portion322.

In the primary pulley3, by adjusting a supply pressure to the oil chamber R1provided in the movable pulley32, the movable pulley32is displaced in the direction of the rotation axis X1. According to the supply pressure to the oil chamber R1, a groove width of the V-shaped groove33between the sheave surfaces312aand322ais changed and the winding radius of the belt V around the primary pulley3is changed.

As shown inFIG.1, the secondary pulley4includes a fixed pulley41and a movable pulley42.

The fixed pulley41includes a shaft portion411arranged along a rotation axis X2and a sheave portion412extending radially outward from an outer periphery of the shaft portion411.

The movable pulley42includes an annular base portion421externally fitted onto the shaft portion411of the fixed pulley41and a sheave portion422extending radially outward from an outer periphery of the annular base portion421.

The sheave portion412of the fixed pulley41and the sheave portion422of the movable pulley42face each other with an interval therebetween in a direction of the rotation axis X2.

In the secondary pulley4, a V-shaped groove43around which the belt V is wound is formed between a sheave surface412aof the fixed pulley41and a sheave surface422aof the movable pulley42.

Bearings44A and44B are externally fitted onto the shaft portion411of the fixed pulley41at one end portion411aand the other end portion411bin the direction of the rotation axis X2.

The other end portion411bof the shaft portion411in the direction of the rotation axis X2is rotatably supported by a support portion102of the transmission case10via the bearing44B.

The one end portion411aof the shaft portion411in the direction of the rotation axis X2is rotatably supported by a support hole16of the side cover13via the bearing44A.

On the sheave portion422of the movable pulley42, a cylinder portion423is provided on a back422bopposite to the sheave surface422a.

The cylinder portion423is provided in a direction along the rotation axis X2.

An outer periphery portion45aof a plunger45faces an inner periphery of the cylinder portion423with a radial gap.

A D-ring8is attached to the outer periphery portion45aof the plunger45. The gap between the inner periphery of the cylinder portion423and the outer periphery portion45ais sealed with the D-ring8.

A fitting portion451having a cylindrical shape is provided on an inner diameter side of the plunger45. The fitting portion451is spline-fitted to the outer periphery of the shaft portion411of the fixed pulley41. The fitting portion451of the plunger45is positioned in the direction of the rotation axis X2between the bearing44B and a stepped portion411cof the shaft portion411.

The plunger45has a region adjacent to the fitting portion451. This region extends in a direction toward the sheave portion422(a left direction in the drawing) from an outer diameter side of the annular base portion421of the movable pulley42and then bends toward the outer diameter side.

One end of a spring Sp abuts against a region452of the plunger45, which bends toward the outer diameter side, from the direction of the rotation axis X2. The other end of the spring Sp abuts against the back422b(a pressure receiving surface) of the sheave portion422. The spring Sp is provided in a state where the spring Sp is compressed in the direction of the rotation axis X2. The movable pulley42is pressed in a direction in which a groove width of the V-shaped groove43is reduced (a direction in which a gear ratio of the variator2is set at a high side) by a biasing force applied by the spring Sp.

In the secondary pulley4, by adjusting a supply pressure to an oil chamber R3provided in the movable pulley42, the movable pulley42is displaced in the direction of the rotation axis X2. According to the supply pressure to the oil chamber R3, the groove width of the V-shaped groove43between the sheave surfaces412aand422ais changed and the winding radius of the belt V around the secondary pulley4is changed.

In the present embodiment, a rotation speed of the primary pulley3is detected by the sensor120. When providing the sensor120, in order to increase a degree of freedom in providing the sensor120, a sensor arrangement structure100having the following configurations is adopted.(a) The sensor120is provided on the side cover13that rotatably supports the fixed pulley31in a direction along the rotation axis X1.(b) Detection target portions (convex portions73described later) to be detected by the sensor120are provided in a region of the plunger7, which can be visually recognized from the direction of the rotation axis X1.

Hereafter, the sensor arrangement structure100will be specifically described.

FIGS.3and3Aare enlarged views showing surroundings of the plunger7.

FIGS.4and4Aare plan views of the plunger7when viewed from the side cover13. In the enlarged view ofFIG.4A, in order to make positions of the convex portions73easy to be recognized, the portions of the convex portions73are hatched.

FIGS.5and5Aare perspective views showing a cross-section of the plunger7taken along a line A-A inFIG.4.

As shown inFIG.3, the plunger7is a press-molded product. The plunger7is positioned on the outer periphery of the shaft portion311of the fixed pulley31. The plunger7is provided in a relatively non-rotatable manner with respect to the fixed pulley31.

As shown inFIGS.4and5, an outer shape of the plunger7is a circular shape when viewed from the direction of the rotation axis X1. The plunger7includes a ring-shaped base portion70when viewed from the direction of the rotation axis X1.

A through hole71is formed in a center of the base portion70. The through hole71penetrates the base portion70in a thickness direction (the direction of the rotation axis X1).

As shown inFIG.3, the shaft portion311of the fixed pulley31is provided with a fitting portion313into which the plunger7is externally fitted. The through hole71of the base portion70is formed at an inner diameter D71matching an outer diameter of the fitting portion313.

The plunger7is press-fitted to an outer periphery of the fitting portion313and abuts against a stepped portion314provided on the fitting portion313.

The bearing34A is further press-fitted into the fitting portion313. The plunger7is provided on the shaft portion311in a state where the plunger7is sandwiched between the stepped portion314and the bearing34A.

As shown inFIG.2, the bearing34A is positioned in the direction of the rotation axis X1by a nut N screwed onto the outer periphery of the fitting portion313. Movement of the plunger7in a direction away from the movable pulley32is restricted by the bearing34A and the nut N.

As shown inFIG.3, the plunger7fixed to the shaft portion311includes a flange portion701provided in a direction perpendicular to the rotation axis X1at the outer periphery70aof the base portion70. The plunger7includes a disk portion702provided in a direction perpendicular to the rotation axis X1at an inner periphery70bof the base portion70.

A thickness W701of the flange portion701in the direction of the rotation axis X1is larger than a thickness W702of the disk portion702in the direction of the rotation axis X1(W701>W702).

The plunger7is formed by press-molding a metal plate. The flange portion701and the disk portion702are provided such that positions thereof are shifted in the direction of the rotation axis X1.

In order to avoid interference with the annular base portion321(the large diameter portion321aand the small diameter portion321b) of the movable pulley32, a region between the flange portion701of the base portion70and the disk portion702of the base portion70has an inner diameter that increases stepwise from the disk portion702toward the flange portion701.

The plunger7includes a first cylindrical wall portion703, a first connecting portion704, a second cylindrical wall portion705, and a second connecting portion706in order from the disk portion702in the region between the flange portion701and the disk portion702.

The first cylindrical wall portion703, the first connecting portion704, the second cylindrical wall portion705, and the second connecting portion706are formed at a thickness substantially equal to the thickness W702of the disk portion702described above. That is, the plunger7includes a thin-walled region formed at a thickness smaller than that of the flange portion701on the inner diameter side relative to the flange portion701.

The first cylindrical wall portion703has a cylindrical shape surrounding the rotation axis X1with an interval therebetween. An end portion of the first cylindrical wall portion703on the bearing34A side (left side in the drawing) is connected to an outer periphery of the disk portion702. A connecting portion between the disk portion702and the first cylindrical wall portion703is curved in a direction away from the bearing34A. Accordingly, the plunger7is in contact only with an inner race34A1of the bearing34A.

The first cylindrical wall portion703is formed at an inner diameter larger than the outer diameter of the small diameter portion321bof the movable pulley32. The first cylindrical wall portion703extends in a direction away from the bearing34A along the rotation axis X1from a lateral side of an outer race34A2of the bearing34A.

The first connecting portion704is provided in a direction perpendicular to the rotation axis X1. The first connecting portion704extends radially outward from an end portion of the first cylindrical wall portion703on the second cylindrical wall portion705side (right side in the drawing).

The second cylindrical wall portion705has a cylindrical shape surrounding the rotation axis X1with an interval therebetween. The second cylindrical wall portion705is formed at an inner diameter larger than that of the first cylindrical wall portion703. Furthermore, the second cylindrical wall portion705is formed at an inner diameter larger than an outer diameter of the large diameter portion321aof the movable pulley32.

An end portion of the second cylindrical wall portion705on the bearing34A side (left side in the drawing) is connected to the first connecting portion704. The second cylindrical wall portion705extends in a direction away from the bearing34A along the rotation axis X1.

The second connecting portion706extends in a direction away from the bearing34A (right direction in the drawing) from an end portion of the second cylindrical wall portion705on the flange portion701side (right side in the drawing).

The second connecting portion706is inclined in a direction in which an inner diameter of the second connecting portion706increases toward the flange portion701away from the bearing34A.

The flange portion701is provided in a direction perpendicular to the rotation axis X1. The flange portion701extends radially outward from an end portion of the second connecting portion706.

An accommodation groove72for the D-ring8is formed on an outer periphery of the flange portion701. The accommodation groove72is formed at a central portion of the flange portion701in a thickness direction (the direction of the rotation axis X1), facing the outer diameter side. The accommodation groove72is provided over the entire circumference in the circumferential direction around the rotation axis X1(seeFIG.5).

The D-ring8is externally fitted and attached in the accommodation groove72. The D-ring8protrudes radially outward from the outer periphery70aof the plunger7.

The disk portion702of the plunger7on the inner periphery70bside is positioned by the shaft portion311of the fixed pulley31.

In the primary pulley3, when the sheave portion322of the movable pulley32is arranged at the farthest position (FIG.3) from the sheave portion312of the fixed pulley31, the flange portion701(right side in the drawing) of the plunger7relative to the first connecting portion704is located inside the cylinder portion323.

In this state, the outer periphery70aof the plunger7is provided on the inner periphery323bof the cylinder portion323with a gap therebetween in the radial direction of the rotation axis X1. The gap between the inner periphery323bof the cylinder portion323and the outer periphery70aof the plunger7is sealed with the D-ring8. The D-ring8is provided on the outer periphery of the flange portion701and is elastically in contact with the inner periphery323bof the cylinder portion323.

Furthermore, the oil chamber R1to which a hydraulic fluid pressure is supplied is defined between the plunger7and the sheave portion322.

The flange portion701is a region that can be visually recognized from the side cover13in the direction of the rotation axis X1. As described above, the support wall portion131of the side cover13is provided in a direction perpendicular to the rotation axis X1. The support wall portion131and the flange portion701have a positional relationship of being parallel to each other and are provided with an interval therebetween in the direction of the rotation axis X1.

In the support wall portion131, an attachment hole131bfor the sensor120penetrates the support wall portion131in the direction of the rotation axis X1. The sensor120is assembled to the side cover13by being inserted into the attachment hole131bfrom the outside of the side cover13. In this state, the sensor120is provided in a direction along the rotation axis X1. A detection portion120aat a tip end of the sensor120faces the flange portion701of the plunger7with an interval therebetween on a center line C120of the sensor120.

The detection target portions to be detected by the detection portion120aof the sensor120are provided on a surface of the flange portion701on the support wall portion131side.

Specifically, the convex portions73that function as detection target portions are provided on the surface of the flange portion701on the support wall portion131side (left side in the drawing).

In the present embodiment, the flange portion701is formed when the plunger7is press-molded. The convex portions73of the flange portion701are formed by a half-blanking process on the flange portion701.

Accordingly, concave portions74recessed inside the flange portion701are formed on the flange portion701. The concave portions74are formed on a side opposite to the convex portions73in the thickness direction of the flange portion701. A protrusion height d1of the convex portions73and a depth d2of the concave portions74are substantially the same.

The half-blanking process may be performed on the surface of the flange portion701on the support wall portion131side (left side in the drawing) so that concave portions are formed on the surface.

In this case, the concave portions formed in the surface on the support wall portion131side (left side in the drawing) are used as detection target portions.

In addition, a configuration in which the convex portions73or the concave portions74are provided only on the surface on the support wall portion131side (left side in the drawing) may be used. In this case, a surface of the flange portion701opposite to the support wall portion131is a flat surface.

As shown inFIGS.4and4A, each of the convex portions73has a substantially rectangular shape when viewed from the direction of the rotation axis X1. A radial length La of the convex portions73is larger than a circumferential length Lb of the convex portions73. A plurality of convex portions73are provided over the entire circumference in the circumferential direction around the rotation axis X1. The plurality of convex portions73are arranged with an interval Wx from each other.

The plurality of convex portions73of the flange portion701all have the same shape.

As shown inFIG.2, the convex portions73protrude from the plunger7toward the side cover13side (left side in the drawing). The detection portion120aof the sensor120supported by the support wall portion131and the region of the plunger7provided with the convex portion73face each other on the center line C120of the sensor120with an interval therebetween.

Accordingly, when the primary pulley3rotates around the rotation axis X1, the convex portions73, which are the detection target portions, pass in front of the detection portion120aof the sensor120at a cycle corresponding to the rotation speed. As a result, the sensor120outputs a pulse corresponding to the passage cycle of the convex portion73.

In the side cover13, the support hole15for the bearing34A is formed on an inner diameter side of the support wall portion131on which the sensor120is provided. A concave portion151used to avoid interference with the shaft portion311of the fixed pulley31is formed in a central portion of the support hole15.

In the side cover13, a bearing retainer9(retainer) is provided on the inner diameter side of the support wall portion131.

In order to avoid interference with the sensor120described above, an outer shape of the bearing retainer9when viewed from the direction of the rotation axis X1is a substantially triangular shape (seeFIG.6).

FIG.6is a plan view of the bearing retainer9.FIG.7is a cross-sectional view of the bearing retainer9taken along the line A-A inFIG.6.

As shown inFIGS.6and7, the bearing retainer9has a plate-shaped base portion90. An opening91having a substantially circular shape is provided in a central portion of the base portion90. An inner periphery surrounding the opening91of the base portion90is located on a virtual circle Im4surrounding the rotation axis X1with an interval therebetween.

In the base portion90, coupling pieces901are provided at intervals of 120 degrees in the circumferential direction around the rotation axis X1. The coupling pieces901extend radially outward from respective outer peripheries90aof the base portion90along straight lines Lm1passing through a center (rotation axis X1) of the virtual circle Im4. In other words, the coupling pieces901protrude radially outward from the respective outer peripheries90aof the base portion90. Outer peripheries901bof the coupling pieces901are located on a virtual circle Im1surrounding the rotation axis X1with an interval therebetween.

Bolt holes901aare formed in the coupling pieces901. Each of the bolt holes901apenetrates the coupling piece901in a thickness direction (direction of the rotation axis X1). When viewed from the direction of the rotation axis X1, a center C of the bolt hole901ais located on a virtual circle Im2surrounding the rotation axis X1with an interval therebetween. The virtual circle Im2has a diameter smaller than that of the virtual circle Im1(Im1>Im2).

The bolt hole901ais located on the straight line Lm1located at the intervals of 120 degrees in the circumferential direction around the rotation axis X1. Here, the straight line Lm1correspond to diameter lines of the virtual circles Im1, Im2, Im3, and Im4.

As shown inFIG.7, a tubular portion902is provided on one surface of the coupling piece901in the thickness direction of the base portion90(direction of the rotation axis X1). The tubular portion902surrounds the bolt hole901aover the entire circumference. The tubular portion902protrudes from the coupling piece901to one side of the coupling piece901in the thickness direction.

In the base portion90, the outer peripheries90aof regions between the coupling pieces901adjacent in the circumferential direction around the rotation axis X1are located closer to the rotation axis X1than the coupling pieces901.

The outer periphery90ahas an arc shape when viewed from the direction of the rotation axis X1. In the outer periphery90a, regions on both sides with respect to an intersection point P with the straight line Lm1are located outside a tangent line Lx of the virtual circle Im3. Then, regions in the vicinity of the coupling pieces901in the outer periphery90aare located inside (rotation axis X1side) the tangent line Lx. The virtual circle Im3is a virtual circle having a diameter smaller than that of the virtual circle Im2and passing through the intersection points P of the straight lines Lm1with the outer periphery90a.

In the base portion90, concave portions910communicating with the opening91are provided in regions intersecting the straight lines Lm1. Each of the concave portions910is formed at a width W910in a direction perpendicular to the straight line Lm1. The concave portion910extends radially outward from the opening91. An outer diameter side of the concave portion910extends to the vicinity of the coupling piece901beyond the virtual circle Im3.

Support pieces903that support the outer race34A2(seeFIG.3) of the bearing34A are provided on an inner diameter side of the base portion90. Each of the support pieces903is formed in a region between the concave portions910adjacent in the circumferential direction.

The support piece903is provided with the concave portions910on both sides in the circumferential direction so that an inner periphery side (rotation axis X1side) of the support piece903can be slightly elastically displaced in the direction of the rotation axis X1.

As shown inFIG.2, the bearing34A is attached to the support hole15of the side cover13. The bearing retainer9is positioned on a surface of the side cover13on the movable pulley32side (right side in the drawing) using the plunger7.

Then, a bolt B is screwed into the bolt hole17aprovided in the side cover13. A shaft portion B1of the bolt B passes through the bolt hole901aprovided in the coupling piece901of the bearing retainer9and the tubular portion902. As a result, the bearing retainer9is pulled toward the side cover13by an engaging force of the bolt B. The support piece903of the bearing retainer9is arranged at a position at which the outer race34A2of the bearing34A is supported (seeFIG.3).

In this state, the support wall portion131of the side cover13and the sensor120supported by the support wall portion131are located radially outside the outer periphery90aof the bearing retainer9.

Then, the detection portion120aof the sensor120and the convex portions73, which are the detection target portions of the plunger7, face each other.

FIGS.8and9show a positional relationship between the bearing retainer9, the plunger7, and the sensor120.

FIG.8shows a state where the bearing retainer9, the plunger7, the sensor120, and the bolts B are arranged in a spaced apart manner in the direction of the rotation axis X1.

FIG.9shows a state where the bearing retainer9, the plunger7, and the sensor120are viewed from the direction of the rotation axis X1.

As shown inFIGS.8and9, the outer shape of the plunger7is a circular shape when viewed from the direction of the rotation axis X1. The outer shape of the bearing retainer9is a substantially triangular shape when viewed from the direction of the rotation axis X1.

Therefore, when viewed from the rotation axis X1, an extra space is present radially outside the outer peripheries90aof the base portion90(see hatched regions R inFIG.9). This space has a size in which the sensor120can be arranged.

As shown inFIG.9, when viewed from the direction of the rotation axis X1, the convex portions73formed on the flange portion701of the plunger7are located on the virtual circle Im1.

As described above, the outer peripheries901bof the coupling pieces901of the bearing retainer9are located on the virtual circle Im1, but the outer peripheries90aof the base portion90are located radially inward of the virtual circle Im1. That is, the regions R surrounded by the virtual circle Im1on the radially outer side of the outer peripheries90aof the base portion90are regions where the sensor120can be arranged without being interfered by the bearing retainer9. Each of the regions R is a region where the convex portions73formed on the plunger7can be visually recognized when viewed from the side cover13(seeFIG.3) in the direction of the rotation axis X1. The bearing retainer9does not overlap the plunger7in the region R when viewed from the direction of the rotation axis X1.

Here, as a comparative example, in a case of a bearing retainer having a circular shape when viewed from the direction of the rotation axis, an inner side of the virtual circle Im1inFIG.9is a region of the bearing retainer.

The bearing retainer9of the present embodiment corresponds to a bearing retainer obtained by notching the regions indicated by symbols R in the drawing from the bearing retainer of the comparative example.

That is, the regions R correspond to portions obtained by partially notching a region of the bearing retainer of the comparative example on an outer periphery side such that each outer periphery90aof the bearing retainer9passes through a center side (rotation axis X1side) relative to the outer periphery (virtual circle Im1) of the bearing retainer having a circular shape of the comparative example. In other words, the regions R correspond to portions obtained by notching the region of the bearing retainer of the comparative example on the outer periphery side, leaving the coupling pieces901.

The regions R can provide an extra space both in the radial direction of the rotation axis X1and in the axial direction of the rotation axis X1.

The sensor120is arranged using the regions R on the radially outer side of the outer periphery90a.

Specifically, as shown inFIG.3, the support wall portion131is closer to the plunger7than to the bearing retainer9. This support wall portion131supports the sensor120.

By providing the sensor120on the support wall portion131, the sensor120is closer to the plunger7than to the bearing retainer9. Accordingly, a region where the sensor120is provided in a housing of the continuously variable transmission1can be made smaller in the direction of the rotation axis X1.

In addition, in the case of the bearing retainer of the comparative example, which has a circular shape when viewed from the direction of the rotation axis X1, in order to avoid interference with the bearing retainer9, the sensor120needs to be arranged outside the virtual circle Im1inFIG.9.

As a result, the region in the housing of the continuously variable transmission1where the sensor120is provided is large in the radial direction of the rotation axis X1.

In the present embodiment, the bearing retainer9has a substantially triangular shape when viewed from the direction of the rotation axis X1. The regions R where the sensor120can be arranged is secured outside the outer periphery90awhen viewed from the direction of the rotation axis X1.

Therefore, the sensor120can face the region where the convex portion73of the plunger7is provided.

Accordingly, compared to the bearing retainer of the comparative example, which has a circular shape when viewed from the direction of the rotation axis X1, it is possible to suitably prevent the region of the housing of the continuously variable transmission1where the sensor120is provided from being large in the radial direction of the rotation axis X1.

In particular, the sensor120may be arranged in a region facing any convex portion73as long as such a region is within the regions R. For example, inFIG.9, the sensor120is arranged at a hatched position, but the sensor120may also be arranged at positions surrounded by dashed circles in the drawing. Therefore, a degree of freedom in arranging the sensor120is increased.

Furthermore, as a comparative example, when a sensor is provided in a direction perpendicular to a rotation axis of a pulley, it is necessary for the sensor to avoid interference with components of a movable pulley that is displaced in a direction of the rotation axis.

Therefore, there are restrictions on where a sensor can be provided in a belt continuously variable transmission.

On the other hand, the present embodiment adopts the following configurations.(a) The sensor120is provided on the side cover13that rotatably supports the fixed pulley31in the direction along the rotation axis X1.(b) The convex portions73, which are detection target portions to be detected by the sensor120, are provided in a region of the plunger7, which can be visually recognized from the direction of the rotation axis X1.

Therefore, the sensor120can be arranged without considering a moving range of the movable pulley displaced in the direction of the rotation axis X1. Therefore, the degree of freedom in providing the sensor120can be further increased.

An example of the sensor arrangement structure100according to one aspect of the present invention will be listed below.(1) The sensor arrangement structure100includes:the primary pulley3(a pulley) that rotates about the rotation axis X1; andthe sensor120that detects rotation of the primary pulley3.

The primary pulley3includesthe fixed pulley31,the movable pulley32that can be displaced relative to the fixed pulley31in a direction of the rotation axis X1, andthe plunger7fixed to the fixed pulley31and defining the oil chamber R1on the back322bof the movable pulley32.

The plunger7is provided with the convex portions73, which are detection target portions, in the flange portion701, which is a region that can be visually recognized from the direction of the rotation axis X1.

The sensor120is provided on the support wall portion131of the side cover13(a support portion) that rotatably supports the fixed pulley31in a direction along the rotation axis X1and faces the region in which the convex portions73of the plunger7are provided.

As a comparative example, when a sensor is provided in a direction perpendicular to a rotation axis of a pulley, it is necessary for the sensor to avoid interference with components of a movable pulley that is displaced in a direction of the rotation axis. As a result, a size of a continuously variable transmission in the direction of the rotation axis is increased.

As described above, in the embodiment, the sensor120is arranged using the plunger7used to define the oil chamber R1. The convex portions73, which are detection target portions, are provided on the flange portion701of the plunger7, which is a region that can be visually recognized from the direction of the rotation axis X1. As a result, it is not necessary to arrange the sensor120in consideration of the interference with the components of the movable pulley32. Therefore, it is possible to suitably prevent the size of the continuously variable transmission1in the direction of the rotation axis X1from increasing.

As a result, the degree of freedom in providing the sensor120can be further increased.(2) The movable pulley32includes the cylinder portion323(a cylindrical wall portion) surrounding the rotation axis X1with an interval therebetween on the back322bof the sheave portion322.

The plunger7includes, on the outer periphery70aside (an outer diameter side), the flange portion701(a flat plate portion) extending in a radial direction of the rotation axis X1from an inner diameter side of the cylinder portion323.

The convex portion73, which is a detection target portion, is provided on the flange portion701.

In this way, since the plunger7, which is an existing component of the continuously variable transmission1, is provided with the convex portion73, which is the detection target portion, it is not necessary to separately provide a separate component for sensing, such as a pulse gear.

When a separate component for sensing is provided, a length of the continuously variable transmission1in the direction of the rotation axis X1is increased by the separate component. Since no separate components are used, it is possible to suitably prevent the continuously variable transmission1from being large in the direction of the rotation axis X1. In addition, since it is not necessary to increase the number of components for sensing, it is possible to suitably prevent an increase in production cost due to an increase in the number of components.

Furthermore, when the number of components increases, there is a concern about the impact of accumulated tolerances. In the present embodiment, since the number of components is not increased, such a concern can be reduced.(3) The detection target portions may be the convex portions73that protrude in the direction of the rotation axis X1or the concave portions74that are recessed in the direction of the rotation axis X1.

With this configuration, the convex portions73that protrude in the direction of the rotation axis X1or the concave portions74that are recessed in the direction of the rotation axis X1can be easily formed on the flange portion701of the plunger7by performing, for example, a half-blanking process.(4) The plunger7includes the accommodation groove72of the D-ring8(a seal support portion) on an outer periphery of the flange portion701(the flat plate portion). The D-ring8externally fitted in the accommodation groove72seals a gap between the inner periphery323bof the cylinder portion323of the movable pulley32and the outer periphery70aof the flange portion701.

The plunger7may include a thin-walled region having a thickness smaller than a thickness of the flange portion701in which the accommodation groove72is formed, on an inner diameter side relative to the flange portion701.

The thin-walled region is a region in which the first cylindrical wall portion703, the first connecting portion704, the second cylindrical wall portion705, and the second connecting portion706on the inner diameter side of the flange portion701are provided.

With this configuration, it is possible to secure a support strength of the D-ring8and improve sealing performance at the flange portion701. Furthermore, by forming the portions other than the flange portion701at a small thickness, a weight of the plunger7can be reduced. That is, it is possible to achieve both improvement in the sealing performance and weight reduction of the plunger7.

In addition, the thin-walled region is formed in a shape whose diameter increases stepwise toward the flange portion701. Therefore, a rigidity of the plunger7can be ensured even when the thickness of the thin-walled region is reduced by about 10% from a thickness of the flange portion701. Therefore, it is possible to reduce the weight of the plunger7while ensuring the rigidity of the plunger7.(5) The convex portion73, which is a detection target portion, may avoid a boundary between the flange portion701in which the accommodation groove72is formed, which is a seal support portion, and the thin-walled region having a thickness smaller than the thickness of the flange portion701.

As a comparative example, when the convex portion73is formed across the boundary between the flange portion701and the thin-walled region, a shape of the convex portion73may be deformed from a designed shape. When the shape of the convex portion73is deformed, detection of the convex portion73by the sensor120is affected, and an output pulse of the sensor120may have a shape different from an expected shape. In such a case, there is a possibility that a rotation speed of the primary pulley3cannot be detected appropriately.

By providing the convex portion73on the flange portion701while avoiding the boundary between the flange portion701and the thin-walled region, the convex portion73can be formed in an appropriate shape. Thereby, the rotation speed of the primary pulley3can be detected appropriately.(6) The fixed pulley31is rotatably supported by the side cover13(the support portion) via the bearing34A.

The side cover13is provided with the bearing retainer9(retainer) that restricts movement of the bearing34A in the direction of the rotation axis X1.

In the bearing retainer9when viewed from the rotation axis X1direction,the coupling pieces901, which are coupling portions coupled with the side cover13, are provided with intervals in a circumferential direction around the rotation axis X1,the outer periphery90abetween the coupling pieces901adjacent in the circumferential direction around the rotation axis X1is located closer to the rotation axis X1than to the coupling pieces901.

The region where the convex portion73(detection target portion) of the plunger7is provided is located on the outer diameter side of the outer periphery90aof the bearing retainer9such that the region can be visually recognized when viewed from the direction of the rotation axis X1.

With this configuration, the region R where the sensor120can be arranged is secured outside the outer periphery90awhen viewed from the direction of the rotation axis X1.

Therefore, the sensor120can face the region where the convex portion73of the plunger7is provided.

Accordingly, compared to the bearing retainer of the comparative example, which has a circular shape when viewed from the direction of the rotation axis X1, it is possible to suitably prevent the region of the housing of the continuously variable transmission1where the sensor120is provided from being large in the radial direction of the rotation axis X1.

In the embodiment described above, the outer shape of the bearing retainer9when viewed from the direction of the rotation axis X1is exemplified as a substantially triangular shape in order to avoid the interference with the sensor120.

The shape of the bearing retainer may be a shape by which the interference with the sensor120can be avoided. For example, as shown inFIG.10, a bearing retainer9A having a substantially quadrangular shape may be used.

FIG.10shows the bearing retainer9A (retainer) according to a modification.FIG.10shows the bearing retainer9A, the sensor120, and the plunger7in an overlapped form.

As shown inFIG.10, an outer shape of the bearing retainer9A is a substantially quadrangular shape when viewed from the direction of the rotation axis X1.

The base portion90of the bearing retainer9A is provided with the coupling pieces901with intervals of 90 degrees in the circumferential direction around the rotation axis X1. The outer periphery90aof a region between the coupling pieces901adjacent in the circumferential direction around the rotation axis X1is located closer to the rotation axis X1than to the coupling pieces901.

In the bearing retainer9A, the outer shape of the bearing retainer9A is a substantially quadrangular shape when viewed from the direction of the rotation axis X1.

Therefore, when viewed from the rotation axis X1, an extra space in which the sensor120can be arranged is present radially outside the outer periphery90aof the base portion90(see hatched regions R inFIG.10).

As shown inFIG.10, the outer peripheries901bof the coupling pieces901of the bearing retainer9A are located on the virtual circle Im1, but the outer periphery90aof the base portion90is located radially inward of the virtual circle Im1. That is, the regions R surrounded by the virtual circle Im1on the radially outer side of the outer periphery90aof the base portion90are regions where the sensor120can be arranged without being interfered by the bearing retainer9A. Each of the regions R is a region where the convex portions73formed on the plunger7can be visually recognized when viewed from the side cover13(seeFIG.3) in the direction of the rotation axis X1. The bearing retainer9A does not overlap the plunger7in the region R when viewed from the direction of the rotation axis X1.

The regions R can provide an extra space both in the radial direction of the rotation axis X1and in the axial direction of the rotation axis X1.

Accordingly, even when the bearing retainer9A is adopted, it is possible to suitably prevent the region of the housing of the continuously variable transmission1where the sensor120is provided from being large in the direction of the rotation axis X1and in the radial direction of the rotation axis X1.

As an aspect of the present invention, an example in which the sensor arrangement structure is applied to a vehicle has been described. The present invention is not limited to the aspect. The sensor arrangement structure can be applied to other than a vehicle.

Although the embodiment of the present invention has been described above, the above embodiment merely exemplifies one application example of the present invention and does not intend to limit the technical scope of the present invention to the specific configuration of the above embodiment.

REFERENCE SIGNS LIST

The present application claims a priority of Japanese Patent Application No. 2021-026257 filed with the Japan Patent Office on Feb. 22, 2021, all the contents of which are hereby incorporated by reference.