JP2003172437A - Structure for cooling belt continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for cooling a belt continuously variable transmission, having improved cooling efficiency by enlarging a space for a cooling air passage. <P>SOLUTION: The belt continuously variable transmission 36 comprises a V-belt 50 set between a driving pulley 43 and a driven pulley and a driving pulley shaft 41 arranged on the side of a crank shaft 38 on a coaxial line with the crank shaft 38, the crank shaft 38 and the driving pulley shaft 41 being connected via an automatic centrifugal clutch device 58 in a disconnectable manner. A driving plate boss 64 for holding the automatic centrifugal clutch device 58 at the end of the crank shaft 38 is provided with an extension portion 67 extending outward to the end of the crank shaft 38, in which a recessed portion 68 is formed. A nut 66 is stored in the recessed portion 68 for fixing the driving plate boss 64 to the crank shaft 38. A one-way clutch 69 is provided on the outer periphery of the extension portion 67 and the one-way clutch 69 is overlapped with the nut 66 in view from the axial direction of the crank shaft 38. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt type continuously variable transmission cooling structure.

[0002]

2. Description of the Related Art Some small vehicles include an engine having a belt-type continuously variable transmission. FIG. 5 is a plan sectional view showing an example of an engine unit provided with a general belt type continuously variable transmission, and FIG. 6 is an enlarged view of a main part VI of FIG. As shown in FIGS. 5 and 6, this engine A
An automatic centrifugal clutch device C is fixed to one end of the crankshaft B by a nut D. Further, a drive pulley shaft F that supports the drive pulley E is arranged on the side of the crankshaft B and coaxially with the crankshaft B, and is connected to the crankshaft B via the automatic centrifugal clutch device C so that it can be connected and disconnected. Has been done. Further, the drive pulley shaft F is rotatably supported by a belt case J of the transmission H by a bearing G disposed adjacent to the automatic centrifugal clutch device C.

On the other hand, the belt type continuously variable transmission H has a drive pulley E, a driven pulley K, and
A cooling device for cooling each member such as the V-belt L is provided. In this cooling device, for example, a drive fan E is integrally provided with a cooling fan M, and when the engine A rotates, the cooling fan M rotates to take in outside air from an intake port N provided in a belt case J. The belt-type continuously variable transmission H is configured to cool each member inside.

Since the cooling fan M is attached to the drive pulley E so as to face the inside of the engine A, the heat generated inside the engine A is transferred to the outside from the exhaust port P provided in the belt case J. It is configured so that it can be discharged.

[0005]

However, when the crankshaft B and the drive pulley shaft F are arranged close to each other in order to reduce the width of the transmission H, the automatic centrifugal clutch device C is provided at one end of the crankshaft B. The fixed nut D and the bearing G that supports the drive pulley shaft F overlap each other, and the diameter of the bearing G is unnecessarily increased, and the bearing G is supported as the diameter of the bearing G increases. The space S between the cooling air passages R formed between the wall Q of the belt case J and the cooling fan surface of the drive pulley E is so narrow that a sufficient amount of outside air cannot be introduced into the transmission H.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cooling structure for a belt type continuously variable transmission in which the cooling air passages are widened to improve cooling efficiency. To do.

[0007]

In order to solve the above-mentioned problems, a belt type continuously variable transmission cooling structure according to the present invention, as set forth in claim 1, is a drive provided on a drive pulley shaft. A V-belt is stretched between a driven pulley provided on the pulley and the driven pulley shaft, and the drive pulley shaft is arranged laterally of the crankshaft and coaxially with the crankshaft.
In a belt type continuously variable transmission in which the crankshaft and the drive pulley shaft are connected to each other by an automatic centrifugal clutch device so that they can be connected and disconnected, a drive plate boss that holds the automatic centrifugal clutch device at the end of the crankshaft. Is provided with an extension portion extending outwardly of the end of the crankshaft, and a recess is formed therein, and a nut for fixing the drive plate boss to the crankshaft is housed in the recess. A one-way clutch is provided on the outer peripheral portion of the installation portion, and the one-way clutch is overlapped with the nut when viewed in the axial direction of the crankshaft.

In order to solve the above-mentioned problems, as described in claim 2, a bearing for axially supporting the drive pulley shaft is arranged between the automatic centrifugal clutch device and the drive pulley, An outside air introducing passage for guiding outside air is provided between the bearing and the drive pulley.

Further, in order to solve the above-mentioned problems,
As set forth in claim 3, of the fixed drive face and the movable drive face constituting the drive pulley, the fixed drive face fixed to the drive pulley shaft in a rotationally integrated manner is arranged on the outside air introduction passage side. A cooling fan is integrally formed on the surface facing the partition wall that separates the clutch chamber for accommodating the automatic centrifugal clutch device and the belt chamber for accommodating the belt type continuously variable transmission.

Further, in order to solve the above-mentioned problems, as described in claim 4, a belt case accommodating the belt type continuously variable transmission is provided, and the belt case is located on the upstream side of the outside air introduction passage. A baffle plate is arranged in the opening of the belt case, and the baffle plate, the partition wall, and the fixed drive face form a cooling baffle passage that is oriented near the axial center of the drive pulley.

In order to solve the above problems,
As described in claim 5, the baffle plate is arranged on the extension line of the inner diameter side edge of the cooling fan.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a right side perspective view showing an example of a saddle riding type four-wheeled vehicle to which the present invention is applied, and FIG. 2 is a plan perspective view thereof.

The saddle type four-wheeled vehicle 1 is provided with a body frame 2 made of, for example, steel pipe. The vehicle body frame 2 includes a pair of left and right front upper pipes 3 and front lower pipes 4, a pair of left and right rear upper pipes 5 and rear lower pipes 6, and a front upper pipe 3 at the front.
And a pair of left and right vertical pipes 7 vertically connecting the front lower pipes 4, and a pair of left and right horizontal pipes 8 connecting the vertical pipes 7 and the front part of the front upper pipe 3 in the front-rear direction A plurality of bridge members 10 to 22 for connecting between the pair of left and right members 3 to 8 in the vehicle width direction, and the like are configured in a substantially cage shape.

A pair of left and right front wheels 25 and rear wheels 26 are provided in front of and behind the vehicle body frame 2 via a suspension mechanism (not shown). The engine unit 27 is positioned between the front and rear wheels 25, 26. Mounted on 2.

A saddle type seat 28 is installed on the rear upper pipe 5 of the vehicle body frame 2, and a fuel tank 29 is installed in front of the seat 28. In front of it, the front wheel 25
A steering handle 30 for steering the vehicle is provided. Further, the front portion of the body frame 2 is extended to substantially above the axle of the front wheel 25, and the engine unit 2 is provided near the front portion thereof.
7 heat exchanger 31 (oil cooler, radiator, etc.)
Is installed. And the engine unit 2 behind it
A cooling fan 32 for cooling 7 is installed.

A front cover 33 is provided on the front part of the vehicle body to cover the front wheels 25 and the upper part of the front part of the body frame 2, and a rear cover 34 is provided on the rear part of the vehicle body to cover the rear wheels 26 and the upper part of the rear part of the body frame 2. The covers 33 and 34 are synthetic resin molded products.

The engine unit 27 is, for example, a four-cycle single cylinder engine 35 and a belt type continuously variable transmission 36 which are integrally formed. 3 is a plan sectional view of the lower portion of the engine unit 27, and FIG. 4 is a main part IV of FIG.
It is the figure which expanded. As shown in FIGS. 3 and 4, a crankshaft 38 is horizontally arranged in a crankcase 37 that constitutes a lower portion of the engine 35 and is orthogonal to the traveling direction of the vehicle. Further, the belt type continuously variable transmission 36 is provided on a side portion of the crankcase 37, which is a right side portion in the present embodiment.
A belt case 39 having the interior is arranged. Further, the right side portion of the belt case 39 is covered with the case cover 40.

The belt type continuously variable transmission 36 is, for example, a drive pulley shaft 41 arranged on the side of the crankshaft 38 coaxially with the crankshaft 38, and behind the drive pulley shaft 41 in parallel with the drive pulley shaft 41. The drive pulley shaft 41 is provided with a drive pulley 43, and the driven pulley shaft 42 is provided with a driven pulley 44.

The drive pulley 43 includes a fixed drive face 45 fixed to the drive pulley shaft 41 so as to rotate integrally therewith, and a movable drive face 46 provided on the drive pulley shaft 41 so as to be rotatable and axially slidable. And the fixed drive face 45 is arranged axially inward (left side in FIG. 3, that is, the crankshaft 38 side) and has a clutch chamber that houses an automatic centrifugal clutch device 58 described later. A cooling fan 47 is integrally formed with the surface of the cooling fan 47 that faces the partition wall 52 that separates the belt chamber that houses the belt type continuously variable transmission 36.

On the other hand, the driven pulley 44 is also a fixed driven face 48 fixed to the driven pulley shaft 42 so as to rotate integrally with it, and a movable driven face provided on the driven pulley shaft 42 so as to be rotatable and axially slidable. The fixed driven face 48 is arranged axially outside (right side in FIG. 3). And both pulleys 43, 44
A V-belt 50 is stretched between them, and the rotation of the drive pulley shaft 41 is transmitted to the driven pulley shaft 42.

The right end of the drive pulley shaft 41 is supported by a bearing 51 provided inside the case cover 40, and the drive pulley shaft 41 is also supported.
The left end of is supported by a bearing 53 provided on the wall 52 of the belt case 39 on the side facing the crankcase 37. A belt case wall 52 (a partition wall that separates a clutch chamber that houses an automatic centrifugal clutch device 58 described later from a belt chamber that houses the belt type continuously variable transmission 36).
The intake port 5 is provided on the front surface of the belt case 39 in the front between the bearing 53 provided on the vehicle and the fixed drive face 45.
4 is formed. An exhaust port 55 is formed on the rear surface of the belt case 39 substantially behind the driven pulley 44, and an outside air introduction passage (cooling air passage 57) is formed between the intake port 54 and the exhaust port 55 substantially along the vehicle traveling direction. It is formed.

A baffle plate 56 is arranged at the opening of the intake port 54 inside the belt case 39. The baffle plate 56 is arranged on an extension line of the inner diameter side edge of the cooling fan 47. The baffle plate 56, the inside of the belt case wall 52 on the side facing the crankcase 37, and the fixed drive face 4 are arranged.
5, a cooling air passage 57 is formed which is oriented near the axial center of the drive pulley 43.

The crankshaft 38 and the drive pulley shaft 41 are connected by an automatic centrifugal clutch device 58 so that they can be connected and disconnected. Further, the driven pulley shaft 42 is a reduction gear mechanism, and a propeller shaft mechanism 60, via a transmission mechanism 59 which is also a power transmission device.
The output of the engine 35 (rotation of the crankshaft 38) is steplessly changed by the belt type continuously variable transmission 36 and transmitted to the front and rear wheels 25, 26 via the propeller shaft mechanisms 60, 61. .

The automatic centrifugal clutch device 58 mainly comprises, for example, a drive plate 62 and a clutch housing 63. The disk-shaped drive plate boss 6 is a sleeve-shaped drive plate boss 6 whose central portion is spline-coupled to the right end of the crankshaft 38 in a rotationally integrated manner.
The drive plate 62 is provided with a clutch weight 65 that is fixed to the outer peripheral surface of the drive plate 62 and is swingably supported in the radial direction on the board surface.

As shown in FIGS. 3 and 4, the drive plate boss 64 has its axial length and position set so as to overlap the clutch weight 65 when viewed in the axial direction of the crankshaft 38, and the crank A nut 66 fastened to the right end of the shaft 38 restricts axial movement.

Further, a sleeve-shaped sleeve extends from the drive plate boss 64 toward the outside of the right end portion of the crankshaft 38, that is, between the drive plate 62 and the belt case wall 52 on the side facing the crankcase 37. An extending portion 67 is provided and a recess 68 is formed therein, and the nut 66 is housed in the recess 68. A one-way clutch 69 is provided on the outer peripheral portion of the extending portion 67 so as to overlap the nut 66 when viewed in the axial direction of the crankshaft 38. On the other hand, the clutch housing 63 has a U-shaped cross section and is arranged so as to concentrically cover the drive plate 62 from the outside, from the right side in FIGS. 3 and 4.

The left end of the drive pulley shaft 41, which is supported by a bearing 53 provided on the belt case wall 52 on the side facing the crankcase 37, projects toward the crankcase 37, and the end of this projecting portion. The part is connected to the outer peripheral surface of the one-way clutch 69, and the clutch housing 63 is fixed to this end part.

A clutch shoe 70 is provided on the outer peripheral edge of the clutch weight 65. When the crankshaft 38 rotates, the clutch weight 65 provided on the drive plate 62 swings radially outward due to centrifugal force, Clutch weight 6 is reached when the specified speed is reached.
5 Clutch lining 71 provided on the inner surface of the clutch housing 63 facing the clutch shoe 70 at the outer peripheral edge
The rotational driving force of the crankshaft 38 is transmitted to the drive pulley shaft 41 by frictionally engaging with.

An alternator 72 is provided at the left end of the crankshaft 38, and a recoil type engine starting device 73 is provided outside the alternator 72.

Further, an induction box 74 made of synthetic resin is provided between the front upper portion of the vehicle body frame 2 and the front cover 33. The induction box 74 and the belt case 39 in which the belt type continuously variable transmission 36 is incorporated. Is connected to the intake port 54 opening at the front of the belt case 39 via a rubber connector pipe (not shown), while the exhaust port 55 opening at the rear of the belt case 39 is made of rubber. The outlet duct 76 is connected via a connector pipe (not shown). A cooling air inlet 77 is provided at the front of the upper surface of the induction box 74 so as to be close to the lower surface of the front cover 33 and open.

Further, as shown in FIG. 1, the inlet duct 75 passes between the heat exchanger 31 and the cooling fan 32,
Further, the layout is such that it extends below the cooling fan 32 and extends rearward to be connected to the intake port 54 of the belt type continuously variable transmission 36.

On the other hand, the outlet duct 76 extends obliquely rearward and upward from the exhaust port 55 of the belt type continuously variable transmission 36, and then turns upward at a steep angle near the upper side of the axle of the rear wheel 26, and Immediately below the rear end of the seat 28, the vehicle is turned to the left side of the vehicle body, and a cooling air discharge port 78 opened to the outside is opened at the most downstream end (the leftmost end) thereof so as to be opened forward.

Next, the operation of this embodiment will be described.

When the engine 35 is operated, the belt type continuously variable transmission 36, which is rotationally integrated with the drive pulley 43 (fixed drive face 45) of the belt type continuously variable transmission 36 arranged inside the belt case 39, is cooled. Fan 4
Since 7 rotates and applies a negative pressure to the inlet duct 75 side, the outside air is sucked into the induction box 74 through the cooling air inlet 77 of the induction box 74 as cooling air, and this cooling air is taken in through the inlet duct 75. It is sucked into the belt type continuously variable transmission 36 through the port 54.

Inside the belt type continuously variable transmission 36, the cooling air is supplied to the drive pulley 43, the driven pulley 44 and the V belt 5.
After cooling each member such as 0, it is discharged from the exhaust port 55 through the connector pipe 46 and the cooling air exhaust port 78 to the outside. When the saddle type four-wheeled vehicle 1 travels forward, the traveling wind blowing from the front is pushed into the induction box 74, so that the amount of cooling air supplied to the belt type continuously variable transmission 36 increases and cooling efficiency is improved. improves.

A sleeve-shaped drive plate boss 64 constituting an automatic centrifugal clutch device 58, which is spline-coupled to the end of the crankshaft 38 in a rotationally integrated manner, extends outward from the end of the crankshaft 38. An extension 67 is provided and a recess 68 is formed therein. A nut 66 for fixing the drive plate boss 64 to the crankshaft 38 is housed in the recess 68, and a crankshaft is provided on the outer periphery of the extension 67. Since the one-way clutch 69 is provided so as to overlap with the nut 66 when viewed in the axial direction of 38, the crankshaft 38 and the drive pulley are not overlapped with the bearing 53 that axially supports the drive pulley shaft 41. The reshaft 41 and the bearing 53 can be arranged close to each other. Diameter also becomes possible.

As a result, the space 79 between the cooling air passages 57 formed by the inside of the belt case wall 52 supporting the bearings 53 and the fixed drive face 45 can be increased,
The cooling efficiency of the belt type continuously variable transmission 36 is improved, and the durability of the V belt 50 is also improved.

Further, by setting the axial length and position of the drive plate boss 64 so as to overlap with the clutch weight 65 in a sectional view, the drive plate boss 64 generated with the swing of the clutch weight 65. It is possible to prevent galling of the crankshaft with respect to the crankshaft 38.

Further, the drive pulley shaft 41 is provided between the automatic centrifugal clutch device 58 and the drive pulley 43.
The bearing 53 that supports the
3 is provided in front of the drive pulley 43, the cooling air can be introduced into the vicinity of the wall 52 of the belt case 39 on the side facing the crankcase 37, which becomes high temperature, and the cooling air can be introduced. Coolability is improved.

Further, among the fixed drive face 45 and the movable drive face 46 constituting the drive pulley 43, the fixed drive face 45 fixed to the drive pulley shaft 41 so as to rotate integrally is arranged on the side of the cooling air intake port 54. With the crankshaft 38
Since the cooling fan 47 is integrally formed on the surface facing to, the stable cooling air can be constantly guided into the belt case 39.

A baffle plate 56 is arranged in the opening of the intake port 54 inside the belt case 39. The baffle plate 56, the inside of the belt case wall 52 facing the crankcase 37, and the fixed drive face 45. And drive pulley 43
By forming the cooling air passage 57 that is oriented near the axis center of the cooling air, new cooling air can be guided to a position that does not interfere with the cooling air pushed out by the cooling fan 47, so that the introduction efficiency of the cooling air is improved. .

Further, if the above-mentioned baffle plate 56 is arranged on the extension line of the inner diameter side edge of the cooling fan 47, the cooling air is guided to the vicinity of the center of the fixed drive face 45 without being blocked by the cooling fan 47. be able to.

[0044]

As described above, according to the cooling structure of the belt type continuously variable transmission according to the present invention, the cooling efficiency of the belt type continuously variable transmission and the durability of the V-belt can be improved.

Further, galling of the drive plate boss on the crankshaft can be prevented.

Further, stable cooling air can be constantly introduced into the belt case accommodating the belt type continuously variable transmission.

[Brief description of drawings]

FIG. 1 is a right side perspective view of a saddle type four-wheel vehicle showing an embodiment of a cooling structure for a belt type continuously variable transmission according to the present invention.

FIG. 2 is a plan perspective view of the saddle type four-wheeled vehicle shown in FIG.

FIG. 3 is a plan sectional view of the lower portion of the engine unit.

FIG. 4 is an enlarged view of a main part IV of FIG.

FIG. 5 is a plan sectional view showing an example of an engine unit including a conventional belt type continuously variable transmission.

FIG. 6 is an enlarged view of a main part VI of FIG.

[Explanation of symbols]

1 saddle type four-wheeled vehicle 27 engine unit 35 engine 36 Belt type continuously variable transmission 38 crankshaft 39 belt case 41 drive pulley shaft 42 Driven pulley shaft 43 Drive pulley 44 driven pulley 45 fixed drive face 46 Movable drive face 47 Cooling fan 50 V belt 52 belt case wall 53 bearing 54 Inlet 56 baffle 57 Cooling air passage 58 Automatic centrifugal clutch device 64 drive plate boss 66 nuts 67 Extension 68 recess 69 one-way clutch

Continued front page    F term (reference) 3J050 AA02 BA03 BB08 BB15 CA02                       CE03                 3J063 AA01 AB22 AC04 BA15 CA01                       CD13                 3J068 AA01 AA05 BA14 BB08 GA06                       GA07

Claims (5)

[Claims] 1. A V-belt is stretched between a drive pulley provided on a drive pulley shaft and a driven pulley provided on a driven pulley shaft, and the drive pulley shaft is provided on a side of the crankshaft and coaxial with the crankshaft. In a belt type continuously variable transmission in which the crankshaft and the drive pulley shaft are connected by an automatic centrifugal clutch device so that they can be connected / disengaged to each other, the automatic centrifugal clutch device is provided at the end of the crankshaft. The drive plate boss to be held is provided with an extending portion extending outward of the end of the crankshaft to form a recess therein, and a nut for fixing the drive plate boss to the crankshaft is housed in the recess. At the same time, install a one-way clutch on the outer peripheral part of the extended part. A cooling structure for a belt type continuously variable transmission, characterized in that the one-way clutch is provided so as to overlap the nut when viewed in the axial direction of the crankshaft. 2. A bearing for axially supporting the drive pulley shaft is arranged between the automatic centrifugal clutch device and the drive pulley, and an outside air introducing passage for guiding outside air is provided between the bearing and the drive pulley. The cooling structure for a belt type continuously variable transmission according to claim 1. 3. Of the fixed drive face and the movable drive face constituting the drive pulley, the fixed drive face fixed to the drive pulley shaft so as to rotate integrally is disposed on the outside air introduction passage side, and the automatic drive The belt type continuously variable transmission according to claim 2, wherein a cooling fan is integrally formed on the surface facing the partition wall that separates the clutch chamber for accommodating the centrifugal clutch device and the belt chamber for accommodating the belt type continuously variable transmission. Machine cooling structure. 4. A belt case for accommodating the belt type continuously variable transmission is provided, and a baffle plate is arranged in an opening portion inside the belt case located upstream of the outside air introduction passage. 4. The cooling structure for a belt type continuously variable transmission according to claim 3, wherein the partition wall and the fixed drive face form a cooling air passage that is oriented near the axial center of the drive pulley. 5. The cooling structure for a belt type continuously variable transmission according to claim 4, wherein the baffle plate is arranged on an extension line of an inner diameter side edge of the cooling fan.