JP2007218334A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device for suppressing the generation of noises by reducing an axially moving distance of a final gear shaft. <P>SOLUTION: At the end of a driving shaft 3 on the side of a bottom portion 2b of a casing 2, a bearing 5 is mounted which is fitted to the driving shaft 3 in a coaxially and relatively rotatable manner. The axial movement of the driving shaft 3 relative to the bearing 5 is restricted by a stepped portion 3c and a thrust washer 6. The bearing is fixed to the bottom portion 2b of the casing 2. A member for restricting the axial movement of the driving shaft 3 in the casing 2 is formed of a metal material with machine work to greatly reduce the axially movable distance of the driving shaft 3 in the casing 2. Thus, the power transmission device suppresses the generation of noises when a gear collides with a case or a cover. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a power transmission device including a drive shaft that receives a driving force of a power source and transmits it to the outside, and is particularly suitable for use in an internal combustion engine.

As a conventional power transmission device, for example, as a power transmission device, for example, one end of the final gear shaft is rotatably inserted into a circular hole of a plate fixed to the bottom of a box-shaped case body. However, the other end of the final gear shaft is rotatably fitted to the bearing portion of the case lid so as to cover the opening of the case body (see Patent Document 1).
JP-A-9-205575

  In the above-described conventional power transmission device, the axial movement of the final gear shaft is restricted by the end surfaces of the final gear coming into contact with the plate of the case body or the case lid.

  On the other hand, the distance between the case body and the case lid is set so that the final gear does not contact the case body and the case lid at the same time in the completed state of the power transmission device and smooth rotation is difficult. Considering variation in finished dimensions, it is set larger. For this reason, the axially movable distance of the final gear shaft is increased.

  As a result, the meshing length of the final gear and the intermediate gear meshing with the final gear varies, and when the power transmission device vibrates, the final gear collides with the case body or the case lid, or noise is generated, or the final gear May collide with the case main body or the case lid, resulting in problems such as wear of the case main body and the case lid.

  Accordingly, the present invention has been made in view of the above-described problems. The power transmission is such that the final gear shaft mounting structure is devised to reduce the movement distance in the axial direction of the final gear shaft, thereby suppressing noise generation. An object is to provide an apparatus.

  In order to achieve the above object, the present invention employs the following technical means.

  The power transmission device according to claim 1 of the present invention includes a bottomed box-like case, a cover fixed so as to close the opening end of the case, and a drive rotatably supported by the bottom of the case and the cover. A shaft and a gear fixed to the drive shaft, the tip of the drive shaft is extended to the outside of the cover, and the tip is provided with a connecting means for transmitting torque by connecting to an external driven shaft The drive shaft is a power transmission device that is driven by transmitting torque from a power source to the gear via one or more intermediate gears, and is coaxial with the drive shaft at the bottom side end of the case of the drive shaft and A bearing member fitted so as to be relatively rotatable is mounted, the drive shaft is provided with a restricting means for restricting movement of the bearing member in the axial direction of the drive shaft, and the bearing member is fixed to the bottom of the case. It is characterized in that.

  In the above-described configuration, the axial movement of the drive shaft is regulated not by contact of the gear with the case or the cover but by contact of the bearing member and the regulating means.

  In the above-described configuration, the axially movable distance of the drive shaft is the size of the axial gap formed between the bearing member and the restricting means. Since the drive shaft and the bearing member are usually formed by machining a metal material, the variation range of the axial clearance formed between the bearing member and the regulating means can be reduced. Therefore, in the conventional power transmission device, it can be made smaller than the axially movable distance of the final gear shaft.

  As a result, it is possible to provide a power transmission device capable of suppressing the occurrence of noise due to the gear colliding with the case or the cover during operation.

  In the power transmission device according to claim 2 of the present invention, the restricting means is in contact with the stepped portion formed on the drive shaft so as to be able to come into contact with the cover side end surface of the bearing member, and the bottom side end surface of the case of the bearing member. The ring member is fixed to the drive shaft as possible.

  According to the above configuration, since one of the restricting means is formed as a step portion of the drive shaft, that is, a part of the drive shaft, the gear collides with the case or the cover while suppressing an increase in the number of parts, and noise Therefore, it is possible to realize a power transmission device that can prevent the occurrence of the above.

  In this case, as a means for fixing the ring member to the drive shaft, as in the power transmission device according to claim 3 of the present invention, a part of the drive shaft is caulked, or claim 4 of the present invention. Either by welding the drive shaft and the ring member as in the power transmission device according to claim 5, or by press-fitting into the drive shaft as in the power transmission device according to claim 5 of the present invention. In this case, the ring member can be easily and firmly fixed to the drive shaft.

  On the other hand, as a method of fixing the ring member to the drive shaft, as in the power transmission device according to claim 6 of the present invention, the ring member is fitted into an annular groove formed in the drive shaft, and the C-shaped ring member is used. A retaining ring, an E-shaped retaining ring, or a C-shaped concentric retaining ring may be used. In this case, if the C-type retaining ring, E-shaped retaining ring or C-shaped concentric retaining ring is a standard product such as a standard part manufactured based on the Japanese Industrial Standard (JIS), the cost of the power transmission device will increase. Can be suppressed. Further, since the C-type retaining ring, the E-shaped retaining ring, or the C-shaped concentric retaining ring can be easily removed even after the assembly, correction or repair at the time of assembly of the power transmission device can be easily performed.

  The power transmission device according to claim 7 of the present invention is characterized in that the bearing member is fixed to the bottom of the case by press-fitting.

  According to the above-described configuration, the drive shaft can be assembled to the case from the opening side of the bottomed box-like case, so that the assembly workability of the power transmission device can be improved.

  Hereinafter, the case where the power transmission device according to the present invention is applied to an actuator 1 used in an intake control device mounted on an engine mounted on an automobile will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of an actuator 1 according to an embodiment of the present invention and an intake control device 100 to which the actuator 1 is mounted.

  FIG. 2 is an enlarged view of part II in FIG.

  FIG. 3 is an enlarged view of part III in FIG.

  4 is a cross-sectional view taken along line IV-IV in FIG.

  The intake control device 100 equipped with the actuator 1 according to the first embodiment of the present invention is installed in an intake manifold of a gasoline engine. The intake control device 100 includes a housing 101 and a butterfly valve 103 as a valve member. The housing 101 is made of, for example, resin. The housing 101 includes an intake passage 102 that communicates with an intake valve of each cylinder of the engine. Since the engine to which the intake control device 100 is attached is a four-cylinder engine, four intake passages 102 are provided as shown in FIG.

  As shown in FIG. 1, the butterfly valve 103 is installed in each intake passage 21. The butterfly valve 103 is formed in a substantially disc shape in accordance with the shape of the intake passage 21 by, for example, resin or metal. As shown in FIG. 1, the butterfly valve 103 is held and fixed to the shaft 15 at the center thereof. Thereby, the butterfly valve 103 rotates the shaft 104 within the rotation center and the intake passage. In addition, as shown in FIG. 1, since four butterfly valves 12 are fixed to one common shaft 104, when the shaft 15 rotates, the four butterfly valves 12 rotate simultaneously and at the same angle. . The shaft 104 is rotatably held by the housing 101 via bearings 105 at both ends thereof.

  The intake control device 100 promotes the mixing of air and fuel by generating vortices in the air flow flowing into the combustion quality of the engine by the action of the butterfly valve 12, or adjusts the flame propagation speed to improve the combustion efficiency. It works to increase or reduce the combustion products contained in the exhaust. The optimum value of the angle of the butterfly valve 12 varies depending on the operating state (load and rotation speed) of the engine.

  For this purpose, the shaft 104 is rotationally driven by the actuator 1 to control the angular position of the butterfly valve 103 to an optimum value.

  Below, the structure of the actuator 1 by one Embodiment of this invention is demonstrated.

  As shown in FIG. 1, the actuator 1 accommodates in a casing 2 a drive shaft 3 rotatably supported by the casing 2 and a cover 12, and intermediate transmission gears 8 and 7 fixed to the drive shaft 3. Is formed. As shown in FIG. 1, the front end of the drive shaft 3 extends to the outside of the cover 12 (the right side in FIG. 1), and the front end of the drive shaft 3 is connected to the shaft 104 which is a driven shaft. A coupling portion 3 a which is a connecting means for transmitting torque to 104 is formed.

  The casing 2 is formed of a resin material, for example, in a bottomed box shape having a bottom 2b on the left side and an opening 2c on the right side in FIG.

  The drive shaft 3 is formed in a shape as shown in FIG. 2 from a metal material such as steel.

  As shown in FIG. 2, a gear 4 is fixed to the drive shaft 3. The gear 4 is made of, for example, a metal material, and is fixed to the drive shaft 3 by, for example, press-fitting. Thereby, when the torque of the motor 10 which is a power source described later is transmitted to the gear 4, the drive shaft 3 thereby rotates integrally with the gear 4.

  On the casing 2 side (left side in FIG. 2) of the drive shaft 3, a small diameter portion 3b having a diameter smaller than that of the gear 4 fixing portion is formed on the same axis, and a restricting means is provided at the boundary between the gear fixing portion and the small diameter portion 3b. The step part 3c is formed. As shown in FIG. 2, a bearing 5 that is a bearing member is rotatably fitted to the small diameter portion 3 b. The bearing 5 is formed in a cylindrical shape from, for example, a metal material. The total length of the bearing 5, that is, the length L1 in the axial direction of the drive shaft 3, is set smaller than the length L2 of the small diameter portion 3b as shown in FIG. As shown in FIG. 2, the bearing 5 is press-fitted and fixed in a holding hole 2 a formed in the bottom 2 b of the casing 2.

  A small diameter portion 3d having a diameter smaller than that of the small diameter portion 3b is coaxially formed on the casing 2 side (left side in FIG. 2) of the small diameter portion 3b, and a step portion 3e is formed at the boundary between the small diameter portion 3b and the small diameter portion 3d. Is formed. As shown in FIG. 2, a thrust washer 6 that is a restricting means and a ring member is fitted in the small diameter portion 3d. The thrust washer 6 is fixed to the drive shaft 3 by partially plastically deforming the end surface 3f of the drive shaft 3 by caulking as shown in FIG. Therefore, the relative movement distance of the drive shaft 3 and the bearing 5 in the axial direction of the drive shaft 3 is L2-L1. Here, since the bearing 5 is press-fitted and fixed to the casing 2, the drive shaft 3 is movable relative to the casing 2 by L 2 -L 1 in the axial direction.

  A bearing 13 is rotatably fitted to the end of the drive shaft 3 on the cover 12 side, and the bearing 13 is fixed to the cover 12. That is, the drive shaft 3 is rotatably supported by the casing 2 and the cover 12 at both ends thereof.

  At the end of the drive shaft 3 on the cover 12 side, a coupling portion 3a is provided as a connecting means for transmitting the torque of the drive shaft 3 to the shaft 104 which is a driven shaft. As shown in FIG. 4, the coupling portion 3 a is formed by providing a groove in the drive shaft 3. On the other hand, a coupling portion 104a that engages with the coupling portion 3a is formed at the actuator 1 side end portion of the shaft 104 that is the driven shaft. As shown in FIG. 4, the coupling portion 104 a is formed by cutting the side surface of the tip portion of the shaft 104 symmetrically. When the coupling portion 3a and the coupling portion 104a are engaged, the inner wall surface of the coupling portion 3a and the outer surface of the coupling portion 104a are pressed and contacted, and torque is applied from the coupling portion 3a to the coupling portion 104a, in other words, from the drive shaft 3 to the shaft 104. Is transmitted, and the shaft 104 is rotationally driven.

  As shown in FIG. 1, an intermediate gear 7 is disposed in the casing 2 so as to mesh with the gear 4. As shown in FIG. 1, the intermediate gear 8 is coaxially fixed to the intermediate gear 7. That is, the intermediate gear 7 and the intermediate gear 8 constitute one part. The intermediate gear 7 and the intermediate gear 8 are rotatably supported by the intermediate shaft 9. On the other hand, the intermediate shaft 9 is fixed to the bottom 2b of the casing 2 as shown in FIG. Therefore, the intermediate gear 7 and the intermediate gear 8 rotate integrally with the intermediate shaft 9 as the rotation center, that is, at the same rotation speed.

  As shown in FIG. 1, a motor 10 as a power source is fixed in the casing 2 by protruding an output shaft 10 a toward the opening 2 c side of the casing 2. A pinion 11 is fixed to the output shaft 10 a of the motor 10, and the pinion 11 is engaged with the intermediate gear 8. As a result, the torque generated by the motor 10 is transmitted to the gear 4 through a path such as the output shaft 10 a → the pinion 11 → the intermediate gear 8 → the intermediate gear 7 → the gear 4. Here, in the actuator 1 according to the embodiment of the present invention, the relationship of the gear of the pinion 11 <the gear of the intermediate gear 8, the gear of the intermediate gear 8 <the gear of the intermediate gear 7, the gear of the intermediate gear 7 <the gear of the gear 4. Is true. Accordingly, the rotational speed of the drive shaft 3 is greatly reduced from the rotational speed of the output shaft 10a of the motor 10.

  The cover 12 is made of, for example, a resin material. As shown in FIG. 1, the cover 12 holds and fixes a bearing 13 that rotatably supports the drive shaft 3. As shown in FIG. 1, the cover 12 is fixed so as to cover the opening 2 c of the casing 2. The method of fixing the cover 12 to the casing 12 may be any of ultrasonic welding, adhesion, screwing, and the like, for example.

  Next, a method for assembling the actuator 1 according to an embodiment of the present invention, particularly a method for assembling the drive shaft 3 to the casing 2, which is a feature of the present invention, will be mainly described.

  First, the gear 4 is fixed to the drive shaft 3 by press fitting.

  Next, the bearing 5 is fitted into the small diameter portion 3 b of the drive shaft 3.

  Next, after the thrust washer 6 is fitted to the small diameter portion 3 d of the drive shaft 3, the end face 3 f of the drive shaft 3 is caulked to fix the thrust washer 6 to the drive shaft 3. At this time, the thrust washer 6 may be firmly fixed to the drive shaft 3 or may be rotatable with respect to the drive shaft 3.

  The assembly of the gear 4, the bearing 5, and the thrust washer 6 to the drive shaft 3 is completed through the above steps.

  Next, the drive shaft 3 assembled with the gear 4, the bearing 5, and the thrust washer 6 is assembled to the casing 2.

  The casing 2 is set with its opening 2c facing upward, the drive shaft 3 is placed with the bearing 5 side facing downward, and the casing 2 is inserted into the casing 2 through the opening 2c of the casing 2, and the bearing 5 is press-fitted into the holding hole 2a. The bearing 5 comes into contact with the step 2d of the holding hole 2a, the press-fitting of the bearing 5 is completed, and the assembly of the drive shaft 3 to the casing 2 is completed.

  Next, the motor 10 is fixed to the casing 2. Here, the pinion 11 is already fixed to the output shaft 10 a of the motor 10.

  Next, the intermediate gear 7 and the intermediate gear 8 which are integral parts are fitted to the intermediate shaft 9 fixed to the casing 2 with the intermediate gear 7 as a lower side. At this time, the intermediate gear 7 is engaged with the gear 4 and the intermediate gear 8 is engaged with the pinion 11.

  Next, the cover 12 is attached to the casing 2. Here, the bearing 12 is already attached to the cover 12. The cover 12 is brought into close contact with the casing 2 while the bearing 13 is fitted to the drive shaft 3, and both are fixed by ultrasonic welding in this state.

  This completes the assembly of the actuator 1 according to the embodiment of the present invention. Here, all the components housed and fixed in the casing 2 are inserted into the casing 2 through the openings 2 c of the casing 2. That is, since it can be assembled by one-way assembly, the number of assembly steps of the actuator 1 can be reduced.

  In the assembly of the actuator 1 according to the embodiment of the present invention, the cover 12 and the casing 2 are fixed by ultrasonic welding. However, the present invention is not limited to this method, and other methods may be used. For example, adhesion, screwing, or the like may be used.

  Next, the effect of the assembly structure of the drive shaft 3 to the casing 2, which is a feature of the present invention, will be described.

  In the conventional power transmission device, the axial movement of the final gear shaft is restricted by both end surfaces of the final gear in the axial direction coming into contact with the plate of the case body and the case lid.

  On the other hand, the distance between the case main body and the case lid in the completed state is set so that the final gear does not simultaneously contact the case main body and the case lid in the completed state of the power transmission device and the rotation of the final gear is not hindered. .

  By the way, the case main body and the case lid are formed by resin molding for cost reduction or the like, but in the resin molding, deformation of the work after molding is likely to occur, and it must be taken into consideration, so in the completed state The distance between the case body and the case lid becomes larger. In other words, the axially movable distance of the final gear shaft between the case body and the case lid is large.

  As a result, the meshing length of the final gear and the intermediate gear meshing with the final gear varies, and when the power transmission device vibrates, the final gear collides with the case body or the case lid, or noise is generated, or the final gear However, the case body collides with the case body or the case lid, and the case body and the case lid are worn out.

  On the other hand, in the actuator 1 according to the embodiment of the present invention, the bearing 5 is coaxially and relatively rotatably fitted to the end of the casing 2 of the drive shaft 3 on the bottom 2b side. The drive shaft 3 includes a step 3c and a thrust washer 6 as restricting means for restricting the bearing 5 from moving in the axial direction of the drive shaft 3, and the bearing 5 is fixed to the bottom 2b of the casing 2. It is configured.

  In the above-described configuration, the axial movement of the drive shaft 3 in the casing 2 is not due to the gear 4 coming into contact with the casing 2 or the cover 12, but the bearing 5 comes into contact with the step 3c or the thrust washer 6. It is regulated by that.

  Specifically, the axial movement of the drive shaft 3 in the casing 2 is the difference between the axial length L1 of the bearing 5 and the axial length L2 of the small diameter portion 3b of the drive shaft 3, that is, L2-L1. Here, the drive shaft 3 and the bearing 5 are formed by machining a metal material. For this reason, the length dimensions L1 and L2 have high accuracy and small tolerances. Therefore, the axially movable distance of the drive shaft 3 in the casing 2 can be made much smaller than the axially movable distance of the final gear shaft in the conventional power transmission device.

  As a result, it is possible to provide a power transmission device capable of suppressing the occurrence of noise due to the gear colliding with the case or the cover during operation.

  In addition, in the actuator 1 by one Embodiment of this invention demonstrated above, although the method of fixing the thrust washer 6 to the drive shaft 3 is used, you may fix by the other method. For example, the thrust washer 6 may be press-fitted into the small diameter portion 3d, or the thrust washer 6 may be welded or brazed to the drive shaft 3.

  In the actuator 1 according to the embodiment of the present invention described above, the thrust washer 6 that is a ring member is used as the restricting means for restricting the relative movement of the drive shaft 3 and the bearing 5 in the axial direction. It is not necessary to limit the thrust washer to other parts. For example, a C-shaped retaining ring, an E-shaped retaining ring, or a C-shaped concentric retaining ring may be used, and an annular groove may be provided in the small diameter portion 3d and attached thereto.

  In the actuator 1 according to the embodiment of the present invention described above, the motor 10 is used as a power source. However, the motor 10 is not limited to the motor 10 and may be another type of power source. For example, a rotary solenoid or a hydraulic motor may be used.

  Further, in the actuator 1 according to the embodiment of the present invention described above, the coupling means between the drive shaft 3 and the shaft 104 which is the driven shaft of the intake control device 100 can be fitted to the groove-like coupling portion 3a. The coupling portion 104a is a simple convex portion, but may be replaced with other types of connecting means. For example, a combination of splines and serrations may be used.

  Moreover, although embodiment described above demonstrated the case where it applied to the actuator 1 used for the intake control apparatus with which an engine is mounted | worn, the use of the actuator 1 is limited to the intake control apparatus with which an engine is mounted | worn. However, it may be used as a rotary actuator in other devices.

It is sectional drawing which shows the structure of the actuator 1 by one Embodiment of this invention. It is the II section enlarged view in FIG. It is the III section enlarged view in FIG. It is the IV-IV sectional view taken on the line in FIG.

Explanation of symbols

1 Actuator (Power transmission device)
2 Casing (case)
2a Holding hole 2b Bottom 2c Opening 3 Drive shaft 3a Coupling (coupling means)
3b Small diameter portion 3c Step portion 3d Small diameter portion 3e Step portion 3f End face 4 Gear 5 Bearing (Bearing member)
6 Thrust washer (ring member)
7 Intermediate gear 8 Intermediate gear 9 Intermediate shaft 10 Motor (power source)
DESCRIPTION OF SYMBOLS 10a Output shaft 11 Pinion 12 Cover 13 Bearing 100 Intake control apparatus 101 Housing 102 Intake passage 103 Butterfly valve 104 Shaft (driven shaft)
104a Coupling part (connection means)
105 Bearing L1 length L2 length

Claims (7)

A bottomed box-like case,
A cover fixed so as to close the open end of the case;
A drive shaft rotatably supported by the bottom of the case and the cover;
A gear fixed to the drive shaft,
The front end of the drive shaft extends to the outside of the cover, and the front end is provided with connection means for transmitting torque by connecting to an external driven shaft,
The drive shaft is a power transmission device that is driven by transmitting torque from the power source to the gear via one or more intermediate gears;
A bearing member that is coaxially and relatively rotatably fitted to the drive shaft is attached to the bottom side end of the case of the drive shaft,
The drive shaft includes a restricting means for restricting the bearing member from moving in the axial direction of the drive shaft,
The power transmission device, wherein the bearing member is fixed to a bottom portion of the case.   The restricting means is fixed to the drive shaft so as to be able to contact a stepped portion formed on the drive shaft so as to be able to contact the cover-side end surface of the bearing member, and a bottom-side end surface of the case of the bearing member. The power transmission device according to claim 1, wherein the power transmission device is a ring member.   The power transmission device according to claim 1, wherein the ring member is fixed to the drive shaft by caulking a part of the drive shaft.   The power transmission device according to claim 1, wherein the ring member is fixed by welding to the drive shaft.   The power transmission device according to claim 1, wherein the ring member is fixed by being press-fitted into the drive shaft.   3. The power according to claim 1, wherein the ring member is a C-shaped retaining ring, an E-shaped retaining ring, or a C-shaped concentric retaining ring that is mounted in an annular groove provided on the drive shaft. Transmission device.   The power transmission device according to any one of claims 1 to 6, wherein the bearing member is fixed to the bottom of the case by press-fitting.

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