JP2016148429A - Friction roller type transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction roller type transmission which secures good sealability achieved by a seal member with a simple structure without deteriorating the torque transmission efficiency even when a high speed side shaft is eccentrically arranged.SOLUTION: The friction roller type transmission includes a bearing unit 45 having: a bearing housing 51; a rolling bearing 53 which is provided at an inner diameter side of the bearing housing 51 and rotatably supports a high speed side shaft 11; and a seal member 59 which is provided at one end part opposite to a friction roller of the bearing housing 51 and closes an internal space 60 including the rolling bearing 53 located at the inner diameter side of the bearing housing 51. The rolling bearing 53 comprises: an inner circumference raceway surface 62 formed on an outer diameter surface of the high speed side shaft 11; an outer circumference raceway surface 61 formed on an inner diameter surface of the bearing housing 51; and rolling elements 70 placed between the inner circumference raceway surface 62 and the outer circumference raceway surface 61.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a friction roller transmission.

  As one of friction roller type transmissions, a wedge roller type transmission using a wedge roller is known. FIG. 6 shows an example of a supercharger equipped with a wedge roller type transmission (see Patent Document 1). The supercharger 111 increases the rotation of the motor input to the low-speed side shaft 113 and rotationally drives the high-speed side shaft 115. The impeller 117 connected to the high speed side shaft 115 compresses the air in the spiral tube 119 by being driven to rotate at a high speed.

  A wedge roller type transmission 121 mounted on the supercharger 111 is shown in a schematic sectional view in FIG. The transmission 121 includes a high-speed side shaft 115, a ring roller 123 disposed around the high-speed side shaft 115 so as to be rotatable in a state in which the rotation axis is eccentric with respect to the rotation axis of the high-speed side shaft 115, Between the shaft 115 and the ring roller 123, there are provided two fixed rollers 125 and 127 and one movable roller 129, which are rotatably arranged.

The ring roller 123 is connected to the low speed side shaft 113 (see FIG. 6), and is rotationally driven integrally with the low speed side shaft 113 by a motor (not shown). The outer diameter surfaces of the fixed rollers 125 and 127 and the movable roller 129 are in rolling contact with the inner diameter surface of the ring roller 123 and the outer diameter surface of the high speed side shaft 115, respectively. The movable roller 129 is a wedge roller supported so as to be able to be slightly displaced in the circumferential direction of the annular space 131, and is elastically pressed by the spring 133 toward a region having a small radial width in the annular space 131. (Arrow P1 in the figure).
Due to the pressing force of the spring 133 against the movable roller 129, the outer diameter surface of the movable roller 129 has a wedge action of pressing the outer diameter surface of the high speed side shaft 115 and the inner diameter surface of the ring roller 123. Then, the pressing force to the high-speed side shaft 115 is propagated to the two fixed rollers 125 and 127 to increase the contact surface pressure of each roller. Further, when the low-speed side shaft 113 is driven to rotate and the ring roller 123 rotates in the R1 direction in the figure, a wedge action similar to the above that presses the movable roller 129 in the P1 direction in the figure occurs.

  In the transmission 121 configured as described above, as shown in FIG. 6, the high-speed side shaft 115 is rotatably supported through a bearing 139 in an insertion hole 137 formed in the center plate 135 of the supercharger. An oil seal 141 is disposed outside the bearing 139 of the high-speed side shaft 115 (on the impeller 117 side) so that the lubricating oil supplied into the transmission 121 does not leak.

JP 2003-201850 A

However, the transmission 121 has a structure in which the rotation shaft of the movable roller 129 moves according to the rotation torque input to the low-speed side shaft 113. Therefore, the high-speed side shaft 115 is pressed in the radial direction according to the transmitted rotational torque, and is eccentric in the radial direction. For this reason, depending on the operating conditions of the transmission 121, the oil seal 141 may be unevenly worn, and a gap may be formed between the high-speed side shaft 115 and the oil seal 141. In that case, there is a possibility that the lubricating oil leaks outside through this gap.
Therefore, it is conceivable to increase the tightening allowance of the oil seal so that no gap is generated between the high speed side shaft 115 and the oil seal 141. However, when the tightening margin is increased, the friction of the oil seal increases, the rotational torque of the output shaft increases, and the torque transmission efficiency of the speed increaser decreases.
Further, since the transmission 121 occupies a large space when mounted on a supercharger or the like, further downsizing and cost reduction are required.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a friction roller type transmission that can ensure good sealing performance with a simple structure without reducing torque transmission efficiency even when the high-speed side shaft is eccentric. .

The present invention has the following configuration.
(1) A high-speed side shaft, at least one friction roller connected to the high-speed side shaft, a low-speed side shaft connected to the high-speed side shaft via the friction roller at a predetermined speed ratio, and at least the high-speed side shaft A friction roller type transmission comprising a casing covering the periphery of the side shaft,
A bearing housing provided between the housing and the high speed side shaft, a rolling bearing provided on an inner diameter side of the bearing housing and rotatably supporting the high speed side shaft, and the friction roller side of the bearing housing; A seal unit that is provided at one end of the opposite side and seals an internal space including the rolling bearing on the inner diameter side of the bearing housing,
The rolling bearing includes an inner raceway surface formed on an outer diameter surface of the high speed side shaft, an outer raceway surface formed on an inner diameter surface of the bearing housing, and the inner circumference raceway surface and the outer circumference raceway surface. A friction roller type transmission comprising a plurality of rolling elements disposed between the friction roller transmissions.
(2) At least one other inner circumferential raceway surface is formed on the outer diameter surface of the high speed side shaft at an axial position different from the inner circumferential raceway surface,
The friction roller transmission according to (1), further comprising an outer ring having an outer raceway surface corresponding to the other inner raceway surface.

  According to the present invention, even when the high-speed side shaft is eccentric, it is possible to satisfactorily ensure the sealing performance by the seal member with a simple configuration without reducing the torque transmission efficiency. As a result, the friction roller type transmission can be reduced in size and cost.

It is a figure for demonstrating embodiment of this invention, and is sectional drawing of the friction roller type transmission of a 1st structural example. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. It is sectional drawing which shows a bearing unit and a high-speed side shaft. It is explanatory drawing which shows typically the mode of the displacement of the bearing unit arrange | positioned in a unit accommodating part. It is sectional drawing which shows the bearing unit and high-speed side shaft of a 2nd structural example. It is a block diagram which shows an example of the supercharger by which the conventional wedge-roller type transmission was mounted. It is typical sectional drawing which shows the transmission of a wedge roller system mounted in the supercharger of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First configuration example>
FIG. 1 is a view for explaining an embodiment of the present invention, a sectional view of a friction roller type transmission, and FIG. 2 is a sectional view taken along line AA in FIG. The friction roller type transmission 100 of this configuration has a particularly high rotational speed such as a compressor that compresses air by increasing the rotational force of a prime mover (motor) and rotationally driving an impeller (impeller) disposed in the spiral tube. Applicable to required equipment.

  As shown in FIGS. 1 and 2, a friction roller type transmission (hereinafter abbreviated as “transmission”) 100 of the first configuration example 100 is parallel to the high speed side shaft 11 and the high speed side shaft 11. A low-speed side shaft 13 that is an input shaft that is arranged and connected to the prime mover, a large-diameter fixed roller 15 that is a fixed roller, a small-diameter fixed roller 17, a wedge roller 19 that is a movable roller, and a ring roller 21. Have. The periphery of each of the rollers 15, 17, and 19 is covered with a housing 23 that is supplied with lubricating oil.

  As shown in FIG. 1, the low speed side shaft 13 has a ring roller 21 concentrically coupled to one end thereof, and transmits the rotational force from the prime mover to the ring roller 21. The ring roller 21 is arranged eccentrically from the rotational axis of the high speed side shaft 11 and rotates integrally with the low speed side shaft 13. That is, the low speed side shaft 13 and the high speed side shaft 11 are connected at a predetermined speed ratio via the friction roller.

  For example, an impeller (impeller) in a spiral tube (not shown) is fixed to the high-speed side shaft 11. The high speed side shaft 11 is driven to rotate, thereby rotating the impeller and compressing the air in the spiral tube.

  Between the ring roller 21 and the high-speed side shaft 11, the above-described large-diameter fixed roller 15, small-diameter fixed roller 17, and wedge roller 19 are provided. The large-diameter fixed roller 15, the small-diameter fixed roller 17, and the wedge roller 19 are configured such that the carrier 29 and the center plate are in contact with the outer diameter surfaces of the high-speed side shaft 11 and the inner diameter surface of the ring roller 21. 31 is supported rotatably.

  As shown in FIG. 2, the wedge roller 19 is disposed in a region having a narrow radial width in the annular space 33 formed between the ring roller 21 and the high-speed side shaft 11. The wedge roller 19 is supported so as to be displaceable in the direction in which the radial width becomes narrower, and is urged by the pressing portion 20 in the direction in which the radial width becomes narrower.

  The low speed side shaft 13 shown in FIG. 1 is supported by a base end portion 35 b of a bowl-shaped low speed shaft housing 35 via a bearing 37. A hook-shaped tip 35a of the low-speed shaft housing 35 is fixed to the center plate 31 by a fastening bolt (not shown).

  The base end portion 35b of the low-speed shaft housing 35 has an axial direction outside the bearing 37 (in the following description, the axial directions of the high-speed side shaft 11 and the low-speed side shaft 13 are simply referred to as axial directions), on the low speed side. An oil seal 39 that seals between the shaft 13 is attached.

  In the center plate 31, the high speed shaft housing 43 is fixed to the side opposite to the fixed side of the low speed shaft housing 35. The high-speed shaft housing 43, the center plate 31 and the low-speed shaft housing 35 are integrated to form a housing 23 that covers the periphery of the rollers 15, 17, and 19.

  The high-speed shaft housing 43 is formed with a unit accommodating portion 47 that accommodates the bearing unit 45. FIG. 3 shows a cross-sectional view of the bearing unit 45 and the high-speed side shaft 11. The bearing unit 45 includes a first bearing unit 45A and a second bearing unit 45B, and the whole is configured in a cylindrical shape.

  The high-speed side shaft 11 is inserted into the cylinders of the first bearing unit 45A and the second bearing unit 45B, respectively, and a large-diameter portion 11a formed in the middle in the axial direction of the high-speed side shaft 11 is a deep groove ball bearing described later. It is rotatably supported by certain rolling bearings 53 and 55.

  The first bearing unit 45 </ b> A includes a rolling bearing 53 provided between the cylindrical bearing housing 51 and the large diameter portion 11 a of the high speed side shaft 11 on the inner diameter side of the bearing housing 51, and one axial end portion of the bearing housing 51. An oil seal 59 as a seal member provided on the O-ring 67 and an O-ring 67 are provided.

  The oil seal 59 is press-fitted and fixed to the high-speed side shaft 11 from the outside of the bearing housing 51 and closes one end side opening of the internal space 60 including the rolling bearing 53 of the bearing housing 51. The oil seal 59 may be a labyrinth seal or a mechanical seal.

  The bearing housing 51 is formed with an annular groove 63 on the outer diameter surface, and an O-ring 67 is attached to the annular groove 63.

  In the rolling bearing 53, the inner and outer rings are configured in common with the bearing housing 51 and the high-speed side shaft 11. That is, the first outer raceway surface 61 is formed on the inner diameter surface of the bearing housing 51 at the other end opposite to the side where the oil seal 59 is disposed. A first inner raceway surface 62 is formed at a position corresponding to the first outer raceway surface 61 on the outer diameter surface of the large-diameter portion 11 a of the high-speed side shaft 11. A ball 70 that is a rolling element is disposed between the first outer raceway surface 61 and the first inner raceway surface 62.

  The bearing housing 51 includes a flange 72 having a radial step between an outer diameter surface of a portion where the first outer raceway surface 61 is formed and an outer diameter surface of a seal fixing portion 71 where the oil seal 59 is disposed. Connected through. Due to the flange 72, the outer diameter of the seal fixing portion 71 is smaller than the outer diameter of other portions.

  The flange 72 is not necessarily provided, but the rigidity of the first bearing housing 51 that receives the axial force from the rolling bearing 53 can be improved by providing the flange 72. In addition, by reducing the diameter of the sliding portion where the oil seal 59 and the high-speed side shaft 11 are in contact, the peripheral speed at the sliding portion can be reduced, and a space-saving seal structure can be realized. According to this, the space efficiency of the bearing unit can be further improved.

  The second bearing unit 45 </ b> B includes a cylindrical bearing housing 52, a rolling bearing 55 provided between the inner diameter side of the bearing housing 52 and the large diameter portion 11 a of the high speed side shaft 11, and an O-ring 69.

  The bearing housing 52 is formed with an annular groove 65 on the outer diameter surface, and an O-ring 69 is attached to the annular groove 63.

  The bearing housing 52 has a second outer raceway surface 74 formed on the inner diameter surface thereof. Further, a second inner peripheral raceway surface 75 is formed at a position corresponding to the second outer peripheral raceway surface 74 on the outer diameter surface of the large diameter portion 11 a of the high speed side shaft 11. A ball 76 that is a rolling element is disposed between the second outer circumferential raceway surface 74 and the second inner circumferential raceway surface 75.

  Thus, the bearing housing 51, the large diameter portion 11a of the high speed side shaft 11 and the ball 70 constitute a rolling bearing 53, and the bearing housing 52, the large diameter portion 11a of the high speed side shaft 11 and the ball 76 constitute a rolling bearing 55. . That is, the bearing housings 51 and 52 function as outer rings of the respective rolling bearings, and the large-diameter portion 11a of the high speed side shaft 11 functions as the inner rings of the respective rolling bearings. The axial positions of the rolling bearings 53 and 55 are set with appropriate intervals so as to obtain a desired moment rigidity.

  The rolling bearings 53 and 55 do not necessarily have the same specifications. The shape of the impeller-side rolling bearing 53 to which a high load is applied may be changed, for example, by making the groove shape of the raceway surface smaller than that of the non-impeller-side bearing 55. Further, the number of rolling elements of the impeller side rolling bearing 53 may be larger than that of the non-impeller side rolling bearing 55.

  This rolling bearing 53 is an angular ball bearing in which the second bearing unit 45B side is the front surface of the outer ring and the opposite side of the second bearing unit 45B side is the front surface of the inner ring. The rolling bearing 55 is an angular contact ball bearing faced to the rolling bearing 53, and the first bearing unit 45A side is the front face of the outer ring, and the opposite side of the first bearing unit 45A side is the front face of the inner ring.

  The first bearing unit 45A and the second bearing unit 45B are disposed with a gap 73 in the axial direction. As shown in FIG. 1, the lubricating oil supply oil passage 77 to which the lubricating oil is supplied opens toward the gap 73 between the first bearing unit 45 </ b> A and the second bearing unit 45 </ b> B, and the lubricating oil is supplied to the gap 73. Supply.

  The lubricating oil supplied to the gap 73 is supplied to the rolling bearings 53 and 55. At that time, the oil seal 59 prevents the lubricating oil from leaking outside the inner space 60 of the bearing housing 51. Further, since the opening of the lubricating oil supply oil passage 77 is disposed between the O-rings 67 and 69, leakage of the lubricating oil to the outside of the internal space 60 can be prevented.

  Further, it is desirable to dispose at least two O-rings 67 and 69 in order to eliminate the inclination of the high-speed side shaft 11.

  As shown in FIG. 1, a preload spring 81 is provided between the end surface (outer ring end surface) of the second bearing housing 52 opposite to the first bearing housing 51 side and the center plate 31. The preload spring 81 is a ring-shaped member that urges the end surface of the second bearing housing 52 in the axial direction. With this preload spring 81, an appropriate preload can be applied to the rolling bearings 53 and 55 shown in FIG.

  According to the transmission 100 configured as described above, the O-rings 67 and 69 protruding from the outer diameter surface of the bearing unit 45 are brought into contact with the unit housing portion 47 of the high-speed shaft housing 43 to house the bearing unit 45. Therefore, the bearing unit 45 is supported so as to be movable in the radial direction by an amount corresponding to the crushing margin of the O-rings 67 and 69 with respect to the unit housing portion 47. That is, the bearing unit 45 is floatingly supported in the unit housing portion 47.

  For this reason, even if the rotating shaft of the wedge roller 19 moves in accordance with the rotational torque input to the low speed side shaft 13 and the high speed side shaft 11 is eccentric, the generated eccentricity causes the O-rings 67 and 69 to be elastically deformed. To be absorbed. Further, since the oil seal 59 moves integrally with the high speed side shaft 11, the oil seal 59 is not crushed by the high speed side shaft 11, and uneven wear does not occur.

  FIG. 4 schematically shows how the bearing unit 45 disposed in the unit accommodating portion 47 is displaced. In the bearing unit 45, when the high-speed side shaft 11 is eccentric, the O-rings 67 and 69 are crushed so that a radial displacement of Δd is allowed in the high-speed side shaft 11. Further, the high-speed side shaft 11 is supported on the outer periphery of the bearing unit 45 by two or more O-rings spaced apart in the axial direction, so that the inclination in the Δθ direction shown in the figure is less likely to occur.

  In the actual transmission 100, the radial movement amount of the high speed side shaft 11 is about 50 μm, and the gap between the unit housing portion 47 and the bearing unit 45 is about 250 μm. Therefore, the gap between the outer diameter surface of the bearing unit 45 and the unit accommodating portion 47 is sufficiently larger than the amount of eccentricity of the high speed side shaft 11, and the eccentricity generated in the high speed side shaft 11 can be reliably absorbed. Therefore, even if the high speed side shaft 11 is eccentric, the oil seal 59 can maintain high sealing performance. Further, the tightening allowance of the oil seal 59 can be designed to be small.

  Since the tightening allowance of the oil seal 59 can be reduced, the loss of rotational torque of the high-speed side shaft 11 is reduced, and the reduction in the speed conversion efficiency of the transmission 100 can be suppressed. The oil seal 59 is not displaced in the radial direction with respect to the high-speed side shaft 11 even when the high-speed side shaft 11 is decentered, so that the seal is not worn unevenly and the lubricating oil does not flow out to the impeller side.

  Furthermore, according to this structure, the raceway ring of a rolling element is formed in the high-speed side shaft 11 and the bearing housings 51 and 52 which rotate at high speed, and the inner and outer rings of the rolling bearings 53 and 55 are integrated with other members. Thereby, the number of parts can be reduced and the whole unit can be reduced in size. In a normal design, a spacer is disposed between the rolling bearings 53 and 55, and members such as a retaining ring and a collar are provided to prevent the rolling bearings 53 and 55 from coming off from the high-speed side shaft 11. Further, a seal housing for accommodating the oil seal 59 is provided separately from the housing that supports the outer rings of the rolling bearings 53 and 55. However, according to the present configuration, these spacers, retaining rings, collars, seal housings, and other parts can be made unnecessary, contributing to downsizing, space saving, and cost reduction.

  In addition, since the high-speed side shaft 11 is supported by the plurality of rolling bearings 53 and 55, even if a large load is generated by the impeller, damage to the high-speed side shaft 11 and its supporting portion may occur and the life may be reduced. Can be suppressed. Therefore, the high-speed side shaft 11 can always be supported stably.

<Second configuration example>
Next, a second configuration example of the transmission will be described. The transmission of this configuration is used when the load by the impeller is small. As shown in FIG. 5, this configuration is the same as the first configuration example described above except that the configuration of the high speed side shaft 11A and the bearing unit 46 is different.

  The high speed side shaft 11A of this configuration has a row of inner peripheral raceway surfaces 83 in the large diameter portion 11a. The bearing housing 82 has an outer raceway surface 85 corresponding to the inner raceway surface 83 and a plurality of rows of annular grooves 87 and 89 formed on the outer diameter surface. The O-ring 67 described above is formed in these annular grooves 87 and 89. 69 are mounted. The oil seal 59 is provided at one end of the bearing housing 82 in the axial direction.

  According to the above configuration, the high-speed side shaft 11A and the bearing unit 46 are more simplified, and the number of parts can be further reduced and further space saving can be achieved. As a result, the transmission can be further reduced in size and cost.

  The present invention is not limited to the above-described embodiments, and the configurations of the embodiments may be combined with each other, or may be modified or applied by those skilled in the art based on the description of the specification and well-known techniques. The invention is intended and is within the scope of seeking protection.

Further, for example, when the rotational speed of the prime mover is very high and a low speed output is required, the transmission 100 can be changed from a speed increaser to a speed reducer by switching the rotation input side and the output side. It can also be used by changing.
Furthermore, the number of wedge rollers that are movable rollers is not limited to one, and a plurality of wedge rollers may be provided. The number of fixed rollers may be one or three or more.

11 High-speed side shaft 13 Low-speed side shaft 15 Large diameter fixed roller (friction roller)
17 Small diameter fixed roller (friction roller)
19 Wedge roller (friction roller)
21 Ring roller (friction roller)
23 Housing 43 High-speed shaft housing 45, 46 Bearing unit 45A First bearing unit 45B Second bearing unit 47 Unit housing portion 51 First bearing housing 52 Second bearing housing 53, 55 Rolling bearing 59 Oil seal (seal member)
60 Internal space 61 First outer raceway surface 62 First inner circumference raceway surface 70,76 Ball (rolling element)
74 Second outer peripheral raceway surface 75 Second inner peripheral raceway surface 82 Bearing housing 83 Inner peripheral raceway surface 85 Outer peripheral raceway surface 100 Friction roller type transmission

Claims (2)

A high speed side shaft, at least one friction roller connected to the high speed side shaft, a low speed side shaft connected to the high speed side shaft via the friction roller at a predetermined speed ratio, and at least the high speed side shaft. A friction roller type transmission comprising a casing covering the periphery,
A bearing housing provided between the housing and the high speed side shaft, a rolling bearing provided on an inner diameter side of the bearing housing and rotatably supporting the high speed side shaft, and the friction roller side of the bearing housing; A seal unit that is provided at one end of the opposite side and seals an internal space including the rolling bearing on the inner diameter side of the bearing housing,
The rolling bearing includes an inner raceway surface formed on an outer diameter surface of the high speed side shaft, an outer raceway surface formed on an inner diameter surface of the bearing housing, and the inner circumference raceway surface and the outer circumference raceway surface. A friction roller type transmission comprising a plurality of rolling elements disposed between the friction roller transmissions. At least one other inner peripheral raceway surface is formed on the outer diameter surface of the high speed side shaft at an axial position different from the inner peripheral raceway surface,
2. The friction roller transmission according to claim 1, further comprising an outer ring having an outer raceway surface corresponding to the other inner raceway surface.