JP4576263B2 - Traction drive device - Google Patents

Description

  The present invention relates to a traction drive device that shifts and transmits a rotational driving force.

  2. Description of the Related Art As a power transmission device that transmits power with low noise and low vibration, a traction drive device including a frictional conduction mechanism having a planetary rolling element such as a roller or a ball is known. In this traction drive device, the rolling element is revolved while rotating between the inner ring and the outer ring, and the cage is rotated by the revolving motion of the rolling element. In this traction drive device, speed change is performed using either the inner ring shaft provided with the inner ring or the cage shaft provided with the cage as the input shaft and the other as the output shaft.

By the way, in this type of traction drive device, it is necessary to apply a preload to the rolling element in order to smoothly rotate the rolling element and to reliably transmit the power from the input shaft to the output shaft by the traction force.
As a structure for applying a preload to the rolling element, there is a structure in which a fluid pressure chamber is provided in a housing on the outer peripheral side of the transmission mechanism section, and a fluid is supplied to this chamber to apply a preload to the transmission mechanism section from the surroundings. (For example, refer to Patent Document 1).
In addition, there is also known one in which a spring is incorporated in the conduction mechanism and a predetermined preload is applied to the rolling element by the biasing force of the spring (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 6-280953 JP 2003-336705 A

By the way, in the apparatus of Patent Document 1, since fluid is supplied to the chamber of the housing and preload is applied to the conduction mechanism portion from the surroundings, other than the conduction mechanism portion, for example, adverse effects such as causing stress on a bearing or the like. There is a fear. In addition, the preload is too low, which occurs in the torque transmission mechanism that exceeds the traction force, causing the rolling elements to slip, leading to wear of components such as the rolling elements, inner rings, outer rings and cages, and shortening the service life. was there.
Further, in the device of Patent Document 2, preload is applied by a spring, and since this spring is built in the device, the rolling element is preliminarily determined by the elastic force of the spring after installation. Only a certain preload is applied. That is, with this device, it is difficult to control the preload according to temperature changes and load fluctuations during operation, and it has been difficult to apply an optimal preload according to the operation status.

  The present invention has been made in view of the above circumstances, and provides an optimal preload according to temperature changes and operating conditions without adversely affecting the surroundings, and exhibits a power transmission function extremely smoothly without problems such as slipping. An object of the present invention is to provide a traction drive device having a long service life.

  In order to achieve the above object, a traction drive device according to the present invention includes a plurality of rolling elements between an inner ring and an outer ring, and includes a cage that holds the rolling elements at intervals in the circumferential direction. The transmission mechanism provided is provided in the housing, and the rolling element revolves between the inner ring and the outer ring while rotating, whereby the inner ring shaft provided with the inner ring and the cage shaft provided with the cage are provided. A traction drive device in which power is transmitted between the inner ring and the outer ring, the inner ring and the outer ring have a raceway surface formed by angle grooves opened on opposite sides, and the raceway surfaces of the inner ring and the outer ring are brought close to the transmission mechanism part. In order to apply preload to the transmission mechanism part, it is equipped with a preload adjustment mechanism that presses the inner ring and outer ring in the axial direction. The preload adjustment mechanism changes the axial pressure between the inner ring and outer ring of the transmission mechanism part. Features that are possible To.

According to the traction drive device having the above-described configuration, the preload is applied by pressing the conduction mechanism portion in the axial direction by the preload adjusting mechanism, and the preload amount to be applied is easily adjusted by adjusting the pressing force. Can do.
As a result, it is possible to give an optimal preload according to temperature changes and operating conditions without adversely affecting the surroundings of the transmission mechanism part, and it is possible to exert the power transmission function extremely smoothly without any problems such as slipping. Long life can be achieved. Further, since it is not necessary to apply a preload at the time of assembling, the assembling can be facilitated, and further, high-precision processing is not required, so that the cost can be reduced.

Further, the traction drive device of the present invention includes a ring-shaped preload adjusting mechanism and an annular piston that protrudes and protrudes in the axial direction by a fluid pressure from a fluid pressure supply source as a driving means. The outer ring is pressed in the axial direction to apply a preload to the transmission mechanism, and the axial pressing force between the inner ring and the outer ring of the transmission mechanism can be changed.
According to this configuration, by adjusting the fluid pressure, the piston can be advanced and retracted very easily, and the amount of preload applied to the transmission mechanism can be adjusted.

In the traction drive device of the present invention, a plurality of transmission mechanism portions are arranged in the axial direction , the preload adjusting mechanism is provided between the transmission mechanism portions that are back and forth with each other, and the annular piston protrudes so that the preload adjusting mechanism is A preload is applied to the front and rear transmission mechanism sections, and the pressing force in the axial direction between the inner ring and the outer ring of the transmission mechanism section can be changed.
According to this configuration, it is possible to perform a shift with a plurality of transmission mechanisms, and it is possible to transmit power with a larger gear ratio.

Further, the traction drive device of the present invention is characterized in that the inner ring shaft and the cage shaft are rotatably connected to each other.
According to this configuration, since the inner ring shaft and the cage shaft are rotatably connected to each other, the support structure for rotatably supporting the shaft with respect to the housing can be simplified, and the apparatus can be made compact. Can be achieved. In addition, since the inner ring shaft and the cage shaft are connected to each other, the pressing force for applying the preload is transmitted in the axial direction via these connecting portions, so that the preload is surely applied to each transmission mechanism. Can be granted.

Furthermore, in the traction drive device of the present invention, it is preferable that a support shaft is provided on one end surface of the inner ring shaft or the cage shaft, and a bearing that rotatably supports the support shaft is provided on the other end surface. .
According to this configuration, the inner ring shaft and the retainer shaft can be reliably connected to each other by the support shaft and the bearing that rotatably supports the support shaft, and the preload is applied through the connection portion. It is possible to reliably transmit the pressing force for the axial direction.

In the traction drive device of the present invention, it is preferable that end surfaces of the inner ring shaft and the cage shaft which are opposed to each other are supported by a pivot bearing so as to be rotatable with respect to each other.
According to this configuration, the inner ring shaft and the retainer shaft can be reliably supported by the pivot bearing between the mutually facing end surfaces of the inner ring shaft and the retainer shaft, and the support portion can be interposed via the support portion. Thus, the pressing force for applying the preload can be reliably transmitted in the axial direction.

  According to the traction drive device of the present invention, it is possible to adjust the preload applied to the transmission mechanism portion very easily without adversely affecting the surroundings. In addition, it is possible to apply an optimal preload according to temperature changes and operating conditions, and it is possible to exhibit a power transmission function very smoothly and to extend the life without problems such as slipping. Further, since it is not necessary to apply a preload at the time of assembling, the assembling can be facilitated, and further, high-precision processing is not required, so that the cost can be reduced.

Hereinafter, embodiments of a traction drive device according to the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view for explaining the structure of the traction drive device according to the first embodiment of the present invention, and FIG. 2 is an exploded perspective view of a transmission mechanism in the traction drive device .
As shown in FIG. 1, the traction drive device 90 includes a cylindrical housing 12 having a through hole 11, and a conductive portion 13 is provided in the through hole 11 of the housing 12. Further, in the traction drive device 90 , one end side (the left side in FIG. 1) of the housing 12 is an input side, and the other end side (the right side in FIG. 1) is an output side. adjusting mechanism 91 is provided.

  As shown also in FIG. 2, the conductive portion 13 includes an input shaft (inner ring shaft) 21 and an intermediate shaft (inner ring shaft, cage shaft) 22 supported so as to be rotatable about the axis of the through hole 11 of the housing 12. And an output shaft (cage shaft) 23, and the input shaft 21, the intermediate shaft 22, and the output shaft 23 are arranged in order from the input side of the housing 12.

  The input shaft 21 includes an inner ring 31 on the output side, and is rotatably supported on the housing 12 by a bearing 32 with the inner ring 31 facing the output side. The inner ring 31 has a raceway surface 31a composed of an angle groove whose output side is open, and a plurality of steel balls 33 as rolling elements are in contact with the raceway surface 31a so as to allow rolling. The bearing 32 that supports the input shaft 21 is a ball bearing provided with an inner ring 32a, an outer ring 32b, and a ball 32c provided between the inner ring 32a and the outer ring 32b.

  The intermediate shaft 22 has a cage 34 formed in a cylindrical shape on the input side, and has an inner ring 35 on the output side. The intermediate portion can be rotated in the through hole 11 of the housing 12 by a bearing 40. It is supported by. The retainer 34 is formed with a plurality of retaining holes 34a at intervals along the circumferential direction. These holding holes 34a are formed to be slightly larger in diameter than the balls 33, and the balls 33 are disposed therein. The inner ring 35 formed on the intermediate shaft 22 has a raceway surface 35a formed of an angle groove whose output side is open, like the above-described inner ring 31, and a plurality of steels that are rolling elements on the raceway surface 35a. The ball 36 is in contact with the ball so as to allow rolling. The bearing 40 that supports the intermediate shaft 22 is an angular ball bearing including an inner ring 40a, an outer ring 40b, and a ball 40c provided between the inner ring 40a and the outer ring 40b.

  The output shaft 23 includes a cylindrical retainer 37 on the input side, and is rotatably supported by the housing 12 by a bearing 38 with the retainer 37 facing the input side. Similar to the retainer 34 described above, the retainer 37 is formed with a plurality of retaining holes 37a at intervals along the circumferential direction. These holding holes 37a are formed to be slightly larger in diameter than the balls 36, and the balls 36 are disposed therein. The bearing 38 that supports the output shaft 23 is a ball bearing including an inner ring 38a, an outer ring 38b, and a ball 38c provided between the inner ring 38a and the outer ring 38b.

  In the through hole 11 of the housing 12, an outer ring 41 and an outer ring 43 formed in an annular shape are respectively disposed on the outer peripheral sides of the balls 33 and 36. Each of the outer ring 41 and the outer ring 43 has raceway surfaces 41a and 43a formed by angle grooves opened on the input side, and the balls 33 and 36 are in contact with the raceway surfaces 41a and 43a so as to allow rolling.

In the conduction part 13, the inner ring 31, the ball 33, the cage 34, and the outer ring 41 constitute a front stage conduction mechanism part (conduction mechanism part) 51, and the inner ring 35, the ball 36, the cage 37 and the outer ring 43 constitute a rear stage conduction. A mechanism part (conduction mechanism part) 52 is configured.
Further, in the through hole 11 of the housing 12, preload transmission rings 53 and 54 are provided between the front transmission mechanism 51 and the bearing 40 and between the bearing 40 and the rear transmission mechanism 52, respectively. .

The bearings 32 and 40 that rotatably support the input shaft 21 and the intermediate shaft 22 with respect to the housing 12 are movable in the axial direction, and the output shaft 23 rotates with respect to the housing 12. A bearing 38 that is movably supported is fixed to the housing 12.
Further, the outer ring 43 constituting the rear-stage conduction mechanism portion 52 is in contact with a step portion 55 formed by making the vicinity of the output side of the through hole 11 slightly smaller in diameter, and movement to the output side is restricted. ing.

As shown in FIG. 1 , the traction drive device 90 includes an annular preload adjusting mechanism 91 between an outer ring 41 of the front-stage transmission mechanism 51 and an outer ring 40 b of a bearing 40 that rotatably supports the intermediate shaft 22. Is provided. As shown in FIG. 3 , the preload adjusting mechanism 91 includes an outer ring 92 provided along the inner peripheral surface of the through hole 11 of the housing 12 and an inner ring provided at a distance from the outer ring 92. A ring 93 and annular pressing pistons 94 provided on both sides of the outer ring 92 and the inner ring 93 are provided. The pressing piston 94 is formed in a T shape in a sectional view, and a part of the pressing piston 94 is slidably disposed between the outer ring 92 and the inner ring 93.

In the preload adjusting mechanism 91, the working fluid is filled in the annular space 95 surrounded by the outer ring 92, the inner ring 93, and the pressing piston 94. A flow path 97 formed in the housing 12 communicates with the space portion 95 in the preload adjusting mechanism 91, and a hydraulic pressure supply source (fluid pressure supply source) which is a driving unit (not shown) is connected to the preload adjusting mechanism 91. As a result, the working fluid in the space 95 is pressurized and depressurized. A seal material 98 is provided between the outer ring 92 and the inner ring 93 and the pressing piston 94, and around the flow path 97 on the outer surface side of the outer ring 92, so that the space 95 is liquid-tight. ing.
The traction drive device 90 is provided with a stopper 99 that restricts the movement of the bearing 32 that rotatably supports the input shaft 21 to the input side.

Then, in the traction drive system 90, the working fluid in the space 95 of the preload adjusting mechanism 91 is pressurized, increases the pressure in the space 95, the pressure piston 94 is projected to both sides. As a result, the outer ring 41 of the front-stage transmission mechanism 51 is pressed to the input side, the bearing 40 is pressed to the output side, and the inner ring 35 of the rear-stage transmission mechanism 52 is pressed to the output side via the bearing 40, A preload is applied to the upstream conduction mechanism 51 and the downstream conduction mechanism 52.
As described above, in the traction drive device 90, the preload applied to the front conduction mechanism 51 and the rear conduction mechanism 52 of the conduction unit 13 is easily adjusted by increasing / decreasing the working fluid of the preload adjustment mechanism 91. be able to.

  In the above configuration, one end side (the left side in FIG. 1) of the housing 12 is the input side and the other end side (the right side in FIG. 1) is the output side, but one end side is the output side and the other end side is the input side. Also good.
  Moreover, in the said embodiment, although the front | former stage conduction | electrical_connection mechanism part 51 and the back | latter stage conduction | electrical_connection mechanism part 52 were provided, the number of conduction | electrical_connection mechanism parts is not limited to two, You may provide one or three or more.

(Second Embodiment)
Next, a traction drive device according to a second embodiment will be described.
In addition, the same structure part as the said 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.
FIG. 4 is a cross-sectional view illustrating the structure of a traction drive device according to the second embodiment of the present invention.
As shown in FIG. 4 , the traction drive device 120 is provided with support shafts 121 and 122 on the input side end surfaces of the intermediate shaft 22 and the output shaft 23, respectively, and on the output side end surfaces of the input shaft 21 and the intermediate shaft 22. Bearings 123 and 124 for rotatably supporting the support shafts 121 and 122 are provided. The bearing 123 is a ball bearing including an inner ring 123a, an outer ring 123b, and a ball 123c provided between the inner ring 123a and the outer ring 123b, and the bearing 124 is similarly an inner ring 124a, an outer ring 124b, and these inner rings. It is a ball bearing provided with a ball 124c provided between 124a and the outer ring 124b.

In the traction drive device 120, the housing 12 is divided into an input side housing 12a and an output side housing 12b. And the conduction part 13 is arrange | positioned in the input side housing 12a, and the bearing 38 which supports the output shaft 23 is arrange | positioned in the output side housing 12b.
In this traction drive device 120, the front conduction mechanism 51 and the rear conduction mechanism 52 are fixed to the input housing 12a by an interference fit such as shrink fitting. As a result, the pre-stage conduction mechanism 51 and the post-stage conduction mechanism 52 are pre-applied in the radial direction from the outer peripheral side by an interference fit to the input side housing 12a.

  According to the traction drive device 120, the support shafts 121 and 122 are provided on the input side end surfaces of the intermediate shaft 22 and the output shaft 23, respectively, and the support shaft 121 is provided on the output side end surfaces of the input shaft 21 and the intermediate shaft 22. , 122 are provided so that the input shaft 21 and the intermediate shaft 22 and the intermediate shaft 22 and the output shaft 23 are rotatably connected to each other. It is possible to simplify the support structure that is rotatably supported, and to shorten the length of the conductive portion 13 in the axial direction, thereby making the device compact. Further, it is possible to reliably apply a preload to the front-stage conduction mechanism 51 and the rear-stage conduction mechanism 52 by interference fit.

( Third embodiment)
Next, a traction drive device according to a third embodiment will be described.
In addition, the same structure part as the said 2nd Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.
FIG. 5 is a cross-sectional view illustrating the structure of a traction drive device according to the third embodiment of the present invention.
As shown in FIG. 5 , the traction drive device 130 is provided with a preload applying spring 131 on the input side of the front-stage conduction mechanism 51. The preload imparting spring 131 is provided between the outer ring 41 of the front-stage transmission mechanism 51 and a holding plate 132 fixed to the input side end surface of the housing 12, and biases the outer ring 41 to the output side by its elastic force. ing. Note that the movement of the outer ring 43 of the rear transmission mechanism 52 to the output side is restricted by the step 133 formed in the through hole 11 of the housing 12.

In the traction drive device 130 having this structure, preload is applied to the pre-stage transmission mechanism 51 by the urging force of the preload applying spring 131, and the intermediate shaft 22 is output via the connecting portion between the bearing 123 and the support shaft 121. By being pressed to the side, a preload is applied to the rear conduction mechanism 52.
Thus, also in the case of the traction drive device 130 according to the third embodiment, the support shafts 121 and 122 are provided on the input side end surfaces of the intermediate shaft 22 and the output shaft 23, respectively, and the input shaft 21 and the intermediate shaft 22 By providing bearings 123 and 124 that rotatably support the support shafts 121 and 122 on the output side end face, the input shaft 21 and the intermediate shaft 22 and the intermediate shaft 22 and the output shaft 23 are connected to each other so as to be rotatable. The support structure for supporting these shafts so as to be rotatable with respect to the housing 12 can be simplified to shorten the length of the conductive portion 13 in the axial direction, and the device can be made compact. Further, the pressing force of the preload applying spring 131 can be transmitted in the axial direction via the connecting portion of the shafts, so that the preload can be reliably applied to the respective transmission mechanism portions 51 and 52.

( Fourth embodiment)
Next, a traction drive device according to a fourth embodiment will be described.
In addition, the same structure part as the said 3rd Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.
FIG. 6 is a cross-sectional view illustrating the structure of a traction drive device according to the fourth embodiment of the present invention.
As shown in FIG. 6 , the traction drive device 140 is provided with a preload transmission pivot bearing (pivot bearing) 141 between the output side end face of the input shaft 21 and the input side end face of the intermediate shaft 22. The intermediate shaft 22 is rotatably supported.
Also in this traction drive device 140, a preload applying spring 131 is provided on the input side of the pre-stage conduction mechanism 51.

In the traction drive device 140 having this structure, preload is applied to the pre-stage transmission mechanism 51 by the biasing force of the preload applying spring 131, and the intermediate shaft 22 is pressed to the output side via the preload transmission pivot bearing 141. As a result, a preload is applied to the rear conduction mechanism 52.
Thus, also in the case of the traction drive device 140 according to the fourth embodiment, the axial length of the conductive portion 13 can be shortened, the device can be made compact, and the preload transmission pivot bearing Through 141, the pressing force of the preload applying spring 131 can be transmitted in the axial direction to reliably apply the preload to each of the transmission mechanism portions 51 and 52.

It is sectional drawing explaining the structure of the traction drive apparatus which concerns on 1st Embodiment of this invention. It is a disassembled perspective view of the transmission mechanism part in a traction drive device. It is sectional drawing explaining a preload adjustment mechanism. It is sectional drawing explaining the structure of the traction drive apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing explaining the structure of the traction drive apparatus which concerns on 3rd Embodiment of this invention. It is sectional drawing explaining the structure of the traction drive apparatus which concerns on 4th Embodiment of this invention.

90, 120 , 130 , 140 ... traction drive device, 12 ... housing, 21 ... input shaft (inner ring shaft), 22 ... intermediate shaft (inner ring shaft, cage shaft), 23 ... output shaft (cage shaft), 31, 35 ... inner ring, 31a, 35a, 41a, 43a ... raceway surface, 33, 36 ... ball (rolling element), 34, 37 ... retainer, 41, 43 ... outer ring, 51 ... pre-stage conduction mechanism part (conduction mechanism part), 52 ... subsequent conduction mechanism (transmission mechanism portion), 91 ... preload adjusting mechanism, 94 ... pressure piston, 1 21,122 ... support shaft, 123 ... bearing, 141 ... preload transmission pivot bearing (pivot bearing)

Claims (4)

A plurality of rolling elements are provided between the inner ring and the outer ring, and a transmission mechanism having a cage that holds the rolling elements at intervals in the circumferential direction is provided in the housing, and the inner ring and the outer ring A traction drive device in which power is transmitted between the inner ring shaft provided with the inner ring and the cage shaft provided with the cage by revolving the rolling element while rotating. There,
The inner ring and the outer ring have raceway surfaces composed of angle grooves that are open on opposite sides,
The transmission mechanism portion includes an annular preload adjustment mechanism that presses the inner ring and the outer ring in the axial direction so that the raceway surfaces of the inner ring and the outer ring are brought close to each other and preload is applied to the transmission mechanism portion. Prepared,
A plurality of the conduction mechanism portions are arranged in the axial direction,
The preload adjusting mechanism includes an annular piston that is provided between the transmission mechanism portions that are in front of and behind each other, and that protrudes and protrudes in an axial direction by a fluid pressure from a fluid pressure supply source that is the outer ring and the driving means. Projecting, the inner ring and the outer ring are pressed in the axial direction, preload is applied to the transmission mechanism part before and after the preload adjustment mechanism, and the inner ring and the outer ring of the transmission mechanism part A traction drive device characterized in that the pressing force in the axial direction can be changed. The traction drive device according to claim 1 , wherein the inner ring shaft and the cage shaft are connected to each other so as to be rotatable. Claim the inner shaft or said cage axis, either on one end face supporting shaft is provided, wherein the bearing which supports rotatably the support shaft to the other end face is provided 2. The traction drive device according to 2. 3. The traction drive device according to claim 2 , wherein end surfaces of the inner ring shaft and the cage shaft that are opposed to each other are rotatably supported by a pivot bearing.

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