JP2007292112A - Spline shaft supporting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spline shaft supporting device using a sliding bearing having a simple constitution for directly supporting a rotatable and reciprocative spline shaft at its spline-machined portion while avoiding damage to a bearing surface. <P>SOLUTION: The sliding bearing for supporting a spline-formed shaft has a bush encircling a spline. The bush can be rotated together with the spline shaft, thereby avoiding the rotation of the spline shaft relative to the bush to prevent damage to the bush caused by the edge of the spline. In a transmission operating mechanism, e.g., the spline 25 is formed and a rotatable and reciprocative operating shaft 2 is borne by the bush 8 having a flange 81. The bush 8 is connected to a bevel gear assembly 6 which rotates the operating shaft 2 with a pawl 82 rotated in association therewith. Thus, the bush 8 is prevented from being rotated relative to the operating shaft and the inner peripheral face of the bush 8 is avoided from being scraped by the edge of the spline 25. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a support device that supports a spline shaft that rotates and reciprocates on a stationary housing, for example, like a spline shaft used in a speed change operation mechanism of a vehicle having an automatic speed change device. About.

  2. Description of the Related Art There are various types of power transmission devices for vehicles, in which a clutch operation is not required and a transmission operation is automated to facilitate driving and reduce driver fatigue. A typical example is an automatic transmission (AT) incorporating a torque converter and a planetary gear. Some automatic transmissions include a parallel shaft gear mechanism-type transmission similar to a manual transmission (MT). There is a power transmission device that automatically switches the gear position according to the traveling state of a vehicle using an electronic control device such as a computer. Such a transmission of the power transmission device includes an actuator that switches a gear position in accordance with a command from the electronic control device.

  The parallel shaft gear mechanism type transmission that automatically switches the transmission gear stage operates the transmission rod (or shift & select lever) in the select direction, as will be described in detail later in connection with the embodiment of the present invention. A select actuator and a shift actuator that operates the rod in the shift direction are installed. As an actuator, instead of a fluid pressure actuator that is heavy and requires a fluid pressure source, an electric actuator using an electric motor as a drive source has been developed in recent years, and a speed change operation mechanism using such an electric actuator is an example. It is shown in JP-A-2002-349797. In the speed change operation mechanism of this publication, a shift & select lever fitted in a spline shaft is slid in the select direction (axial direction), and further, the spline shaft is rotated to operate the lever in the shift direction. The shaft is fixed in the axial direction. However, in a speed change operation mechanism using an electric actuator, a transmission rod or the like is often operated using a spline shaft that rotates and reciprocates in the axial direction for the purpose of simplifying the operation mechanism.

The spline shaft has an axial groove formed on the outer periphery thereof, and is used to fix a component fitted on the shaft in the rotational direction. The mechanism that allows the spline shaft to rotate and reciprocate is used not only in a vehicle speed change operation mechanism equipped with an electric actuator but also in various mechanical devices. For example, Japanese Patent Application Laid-Open No. 2004-293631 discloses a “slide spline device” applied to a general industrial robot. In the robot described in this publication, a chuck device for gripping a workpiece is moved in the vertical direction and rotated. In order to move and position in the direction, a spline shaft that can rotate and reciprocate is used.
Japanese Patent Application Laid-Open No. 2002-349797 JP 2004-293631 A

  In order to operate a mechanical device such as a transmission using such a spline shaft, it is necessary to support the spline shaft on a stationary part such as a housing so that the spline shaft can rotate and reciprocate. In general, the rotating shaft is supported by a stationary part via a bearing, and a sliding bearing in which a bush is press-fitted into a housing or the like is often used as the bearing from the viewpoint of simplicity of structure and cost. A plain bearing has a smooth cylindrical surface made of a relatively soft material such as a synthetic resin or a metal alloy on a bearing surface that contacts a peripheral surface of a shaft and supports a load. When the spline shaft is rotatably supported by such a sliding bearing, the following problem occurs.

  As shown in FIG. 5, the spline shaft is provided with a large number of axial grooves on the outer periphery, and continuous rectangular irregularities are formed on the outer periphery of the cross section. Corresponding concavities and convexities are formed on the inner peripheral surface of the component fitted on the shaft, and the component is mounted so that it can slide in the axial direction but cannot rotate relative to it (spline fitting). The end E of the convex portion is an edge portion, and when the spline shaft rotates while in contact with the bearing surface of the sliding bearing, due to the phenomenon that the material of the bearing surface is scraped off by the edge portion of the convex portion or the occurrence of so-called scuffing, This will cause damage to the bearing surface. Therefore, when the spline shaft is supported by the sliding bearing, as shown in FIG. 5, the portion that contacts the bearing surface of the bearing does not process the spline but supports the load here as a smooth cylindrical surface. Splines are formed on both sides. Alternatively, as shown in FIG. 6, a collar may be inserted between the bush serving as a sliding bearing and the spline shaft to prevent the edge of the spline from coming into contact with the surface of the bush.

However, when processing splines on both sides of the cylindrical surface, separate processing is required. Furthermore, in many splines used for the operation mechanism and the position control mechanism, the phase in the rotational direction of the members fitted in the splines on both sides is strictly managed, and the positions of the grooves formed in the splines on both sides are circular. Processing must be performed so as to accurately match the circumferential direction, and the processing process becomes complicated. Further, when a collar is inserted between the slide bearing and the spline shaft, the number of parts increases and the assembly process becomes complicated.
It is an object of the present invention to directly support a spline shaft that can be rotated and reciprocated on a stationary part by directly supporting the spline processed part by a bearing having a simple structure, and avoiding damage to the bearing surface. To do.

In view of the above problems, the present invention provides a bush that surrounds a spline shaft as a slide bearing that supports a spline shaft that can rotate and reciprocate, and the bush is rotated together with the spline shaft. Relative rotation is eliminated, and damage to the bush due to the edge of the spline is prevented. That is, the present invention
“A bearing device that supports a rotatable and reciprocating spline shaft in a support hole formed in a stationary part,
A bush having a cylindrical portion is installed between the spline shaft and the support hole, the outer peripheral surface of the bush is brought into contact with the support hole, and the inner peripheral surface of the bush is brought into contact with the spline forming portion of the spline shaft. Let
Connecting means is provided between the bush and the spline shaft, the bush rotates in conjunction with the spline shaft, and the spline shaft reciprocates within the bush.
The bearing device is characterized by this.

  According to a second aspect of the present invention, the connecting means may be a protrusion that is formed on the inner peripheral surface of the bush and engages with a groove of the spline forming portion.

  According to a third aspect of the present invention, the connecting means can be provided between the bush and a member that is spline-fitted to the spline shaft so as not to rotate relative to the spline shaft. In this case, as described in claim 4, the bush is formed with a flange portion that abuts against the wall surface of the stationary portion in which the support hole is formed, and a protrusion is provided on the flange portion to form the spline fitting. It is preferable to engage with a member to be engaged.

  As described in claim 5, the spline shaft can be applied to operate a transmission for a vehicle.

In the present invention, as a sliding bearing for supporting a rotatable and reciprocating spline shaft on a stationary portion such as a housing, a bush surrounding the spline shaft is provided and fitted into a support hole of the stationary portion. In this bush, the cylindrical outer peripheral surface is in contact with the support hole, the inner peripheral surface is in contact with the spline forming portion of the spline shaft, and the support hole and the spline shaft are in a so-called gap fitting state. Yes. Furthermore, a connecting means is provided between the bush and the spline shaft, and the bush is rotated in conjunction with the spline shaft.
The bush surrounding the spline shaft rotates in conjunction with the spline shaft, and the relative rotation between the spline shaft and the bush is eliminated. As a result, even if the inner peripheral surface of the bush is in contact with the spline forming portion, the edge portion of the spline does not relatively rotate, so that damage such as scraping of the inner peripheral surface of the bush by the edge portion can be prevented. . In the present invention, the outer peripheral surface of the bush rotates and slides with respect to the support hole of the housing or the like to become a bearing surface for the rotation of the spline shaft, and the inner peripheral surface becomes a bearing surface for the reciprocating motion of the spline shaft. As described above, since the movements in the two directions are received by the separate surfaces of the bush, the wear of the bush due to sliding can be reduced and the durability thereof can be improved.

  When the protrusion is formed on the inner peripheral surface of the bush and this is engaged with the groove of the spline forming portion as in the invention of claim 2, the connecting means is constituted by a simple structure, and the bush is interlocked with the spline shaft. It becomes possible to rotate.

  In general, a member that is spline-fitted so as not to rotate relative to the shaft, such as a gear for rotating the shaft, is fitted into the spline shaft. Therefore, as in the third aspect of the present invention, a connecting means is provided between the spline fitting member and the bush, and the bush can be rotated in conjunction with the spline shaft. In this case, it is possible to configure the connecting means relatively freely, and since there is no projection that engages with the spline as in the invention of claim 2, resistance to the reciprocating motion of the spline shaft is reduced.

  When connecting means is provided between the spline-fitting member and the bush, as in the invention of claim 4, the bush is formed with a flange portion that abuts against the wall surface around the support hole and a protrusion. The projecting portion can be engaged with a member that is spline-fitted to form a connecting means. At this time, the axial position of the bush is positioned by the flange portion, and it is possible to receive a thrust load acting on a member or the like that is spline-fitted by the flange portion.

  Since this bearing device is a simple and compact sliding bearing with a low cost, it is suitable for an operating mechanism of a vehicle transmission having a limited mounting space, as in the invention of claim 5. is there.

Hereinafter, embodiments of the bearing device of the present invention will be described with reference to the drawings. In this embodiment, the present invention is applied to a shift operation mechanism of a vehicle transmission. First, the structure and operation of the shift operation mechanism will be described in detail with reference to FIG.
As is well known, in a parallel shaft gear mechanism type transmission, a plurality of shift rods (sometimes referred to as fork shafts) arranged in parallel are moved in the axial direction, so that they are integrated with the shift rod. A gear shift sleeve for power transmission is engaged with a gear (dog tooth) via a fork to perform a shift. The transmission is provided with a transmission rod or shift & select lever for moving the shift rod, which engages with one of the plurality of shift rods and moves in the axial direction. To select the shift rod to be moved and move it further in the axial direction, the transmission rod, etc. is movable in the perpendicular and axial directions of the shift rod. Select the movement of the rod in the perpendicular direction and shift the axial movement. Call it.

  An upper view of FIG. 1 shows a plan view of a main part of a speed change operation mechanism using an electric actuator, and a lower view thereof shows a front view. An operation shaft 2 that is supported by the housing 1 and extends in the lateral direction is installed in the speed change operation mechanism. The operation shaft 2 can rotate as indicated by an arrow A and can reciprocate as indicated by an arrow B. 1 is supported. As shown in the figure below, the transmission rod 3 is disposed below the operation shaft 2 and is fixed to the arm block 31 and can be rotated (selected) as indicated by an arrow C, while at the same time being perpendicular to the paper surface. It can be slid (shifted). Although illustration is omitted, the transmission rod 3 extends in the direction perpendicular to the paper surface, and an arm provided at the tip thereof selectively engages one of the plurality of shift rods by the movement of the selection. Then, the shift rod engaged by the shift movement is slid, and the shift sleeve is moved by the fork integrated with the shift rod to engage or separate the transmission gear.

  Rack teeth 32 are formed on the upper surface of the arm block 31 of the transmission rod 3, and both upper ends of the arm block 31 are sandwiched between the forked holder 4. The holder 4 is rotatably fitted to the operation shaft 2 and is fixed in the axial direction by a snap ring. The arm block 31 rotates as indicated by an arrow C in accordance with the reciprocation of the operation shaft 2 in the axial direction. The arm at the tip of the transmission rod 3 moves in the select direction. Further, a shift pinion 5 that is spline-fitted to the operation shaft 2 is disposed at the center of the bifurcated holder 4 and meshes with the rack teeth 32 of the arm block 31. Thus, when the operation shaft 2 rotates, the shift pinion 5 also rotates, and the transmission rod 3 moves in the shift direction.

  A shift actuator 21 composed of an electric motor and a select actuator 22 are mounted on the housing 1 of the transmission. The shift actuator 21 is a bevel gear that is spline-fitted to the left portion of the operation shaft 2 via the bevel gear transmission 23 so that the operation shaft 2 and the shift pinion 5 are rotationally driven to move the transmission rod 3 in the shift direction. Connected to the assembly 6. On the other hand, a rack sleeve 7 formed with rack teeth is fitted in the small diameter portion on the right side of the operation shaft 2, and the select actuator 22 reciprocates the operation shaft 2 in the axial direction to move the tip of the transmission rod 3. It is connected to the rack sleeve 7 by a transmission device 24 having a worm gear and a pinion gear so as to move in the select direction. That is, the operation shaft 2 on which the spline 25 is formed is configured to rotate by the shift actuator 21 and to reciprocate by the select actuator 22. The housing 1 is provided with a detection switch SA for detecting the rotational position of the operation shaft 2 and a detection switch SB for detecting the axial position in order to determine the gear position of the transmission.

  At the time of shifting, first, the shift actuator 21 rotates the bevel gear assembly 6 via the bevel gear transmission 23 and rotationally drives the operation shaft 2 and the shift pinion 5 to move the transmission rod 3 in the shift direction. Then, the gears (dog teeth) of the shift stage and the shift sleeve are disengaged to set the neutral state. Next, the select actuator 22 reciprocates the operating shaft 2 in the axial direction to move the tip of the transmission rod 3 in the select direction, thereby engaging the tip with a desired shift rod. In this state, the shift actuator 21 is driven again, the transmission rod 3 is moved in the shift direction, and the speed change sleeve is engaged with the gear of the new speed stage.

  Thus, the operation shaft 2 can rotate and reciprocate, and a continuous spline 25 is formed in a portion from the left end of the operation shaft 2 to the shift pinion 5. The shift pinion 5 is spline-fitted to the operation shaft 2 so as not to be relatively rotatable, and the bevel gear assembly 6 is also spline-fitted to the left of the left end portion of the operation shaft 2 so as not to be relatively rotatable. The bevel gear assembly 6 is fixed in the axial direction by the wall portion of the housing 1, and the operation shaft 2 reciprocates at the center thereof.

  The operation shaft 2 is supported by bearings at two locations on the wall portion of the housing 1, and the left bearing in FIG. 1 is for bearing the shaft portion on which the spline 25 is formed. The inventive bearing device is used. As shown in the enlarged view of the bearing portion in FIG. 2, a support hole 11 through which the operation shaft 2 passes is provided in the wall portion of the housing 1, and a bush 8 that is a sliding bearing of the present invention is fitted into the support hole 11. .

  As shown in FIG. 3, the bush 8 is a cylindrical member having a flange portion 81 formed at an end portion in the axial direction, and is made of a synthetic resin having excellent lubricity. The two splines 25 are slidably contacted while reciprocating. In FIG. 2, the hub portion 61 of the bevel gear assembly 6 is spline-fitted to the left operation shaft 2 of the bush 8, and both ends of the hub portion 61 are the wall surface of the housing 1 and the flange portion of the bush 8. Abutting 81 is fixed in the axial direction. A shift pinion 5 disposed between the bifurcated holder 4 is spline-fitted to the operation shaft 2 on the right side of the bush 8. Since the spline 25 of the operation shaft 2 is continuously formed from the left bevel gear assembly 6 to the right shift pinion 5, the phase between the bevel gear assembly 6 and the shift pinion 5 is accurately set. Is easy.

  The flange portion 81 of the bush 8 is provided with a claw portion 82 having a substantially rectangular cross section. Further, a concave portion having a rectangular cross section corresponding to the claw portion 82 is formed on the end surface of the hub portion 61 of the bevel gear assembly 6, and the claw portion 82 is fitted into the concave portion to constitute a connecting means. For this reason, the bevel gear assembly 6 rotates the operating shaft 2 to be spline-fitted and rotates the bush 8 in conjunction with the hub portion 61. In the rotating bush 8, the outer peripheral surface of the cylindrical portion slides on the inner surface of the support hole 11 of the housing 1 to support a radial load such as the operation shaft 2, and the flange portion 81 is a side surface of the wall portion of the housing 1. The thrust load acting on the bevel gear assembly 6 is supported.

  The spline 25 of the operation shaft 2 slides on the inner surface of the cylindrical portion of the bush 8 by the reciprocation of the operation shaft 2. At this time, the bush 8 rotates together with the operation shaft 2, and there is no relative rotation between the two. Therefore, the edge portion of the spline 25 does not move in the rotation direction on the inner surface of the bush 8 and even if the bush 8 is made of a synthetic resin which is a flexible material, the inner surface of the bush 8 is not damaged by the edge portion. Avoided. The inner surface of the cylindrical portion of the bush 8 becomes a sliding surface that supports the movement of the operation shaft 2 in the axial direction, and the outer sliding surface becomes a sliding surface that supports the movement in the rotation direction, and each movement is shared and supported. Will be.

  Another embodiment of the bearing bush that rotates together with the operation shaft 2 is shown in FIG. 4 (the right figure is a sectional view). The bush 8A has a cylindrical portion 8B and a flange portion 8C, like the bush 8 described above, and the cylindrical portion 8B is in contact with the support hole 11 of the housing 1 so that the flange portion 8C contacts the bevel gear assembly 6. And the operation shaft 2. The flange portion 8C is not provided with a claw portion, and as a connecting means instead, a large number of projection portions 8D that fit into the splines 25 are formed on the inner surface of the end portion of the cylindrical portion 8B. The protrusion 8D prevents relative rotation between the bush 8A and the operation shaft 2, and the bush 8A can achieve the same effects as the bush 8 of the above embodiment. Note that the protrusions 8D are not necessarily provided corresponding to all the grooves of the spline 25, and may be formed as many as necessary to reliably prevent relative rotation.

  As described above in detail, when the spline shaft capable of rotating and reciprocating is supported on the stationary portion, the present invention provides a bush that surrounds the spline shaft as a slide bearing, and the spline shaft rotates with the spline shaft. This prevents the bush from being damaged by the edge portion. In the above-described embodiment, the application to the spline shaft of the speed change operation mechanism has been described. However, the bearing device of the present invention positions the spline shaft of another mechanical device, for example, the chuck device described in Patent Document 2. Needless to say, the present invention can also be applied to a bearing device that supports a spline shaft for a stationary frame or the like. In addition, it is possible to make various modifications to the embodiment, such as applying an abrasion-resistant surface treatment to the outer peripheral surface of the bush, or adopting a metal bush with a lubricating material provided on the surface as the bush. it is obvious.

It is a figure which shows the operation mechanism of the transmission for vehicles to which the bearing apparatus of this invention was applied. It is an enlarged view of the bearing apparatus part of this invention in FIG. It is a figure which shows the Example of the bush of this invention. It is a figure which shows another Example of the bush of this invention. It is a figure which shows the prior art example of the bearing apparatus which supports a spline shaft. It is a figure which shows another prior art example of the bearing apparatus which supports a spline shaft.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 11 Support hole 2 Operation shaft 21 Shift actuator 22 Select actuator 25 Spline 3 Transmission rod 5 Shift pinion 6 Bevel gear assembly 61 Hub part 8, 8A Bushing 81, 8C Flange part 82 Claw part 8D Protrusion part

Claims (5)

A bearing device for supporting a spline shaft (2) capable of rotating and reciprocating in a support hole (11) formed in a stationary part,
A bush (8, 8A) having a cylindrical portion is installed between the spline shaft (2) and the support hole (11), and an outer peripheral surface of the bush (8, 8A) is formed in the support hole (11). Contacting the inner peripheral surface of the bush (8, 8A) with the spline forming portion of the spline shaft (2);
Connection means (82, 8D) is provided between the bush (8, 8A) and the spline shaft (2), the bush (8, 8A) rotates in conjunction with the spline shaft (2), and The bearing device is characterized in that the spline shaft (2) reciprocates in the bush (8, 8A). 2. The bearing device according to claim 1, wherein the connecting means is a protrusion (8 </ b> D) formed on an inner peripheral surface of the bush (8 </ b> A) and engaged with a groove of the spline forming portion. The spline shaft (2) is fitted with a member (6) which is spline fitted so as not to rotate relative to the shaft, and the connecting means (82) is provided between the bush and the member. The bearing device described in 1. The bush (8) is formed with a flange portion (81) that abuts against the wall surface of the stationary portion in which the support hole (11) is formed, and the connecting means is formed on the flange portion (81) and the member. The bearing device according to claim 3, wherein the bearing device is an engaging claw portion. The bearing device according to any one of claims 1 to 4, wherein the spline shaft (2) operates a transmission for a vehicle.

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