JPH0332517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shift device that is installed in an outboard motor or a propulsion unit of an outboard motor and switches a propulsion propeller between normal rotation, reverse rotation, and neutral rotation.

Shift devices for outboard motors and inboard/outboard motors mesh with forward and reverse gears that rotate in opposite directions on the output shaft that drives the propulsion propeller, and a sleeve that slides in the axial direction on the output shaft. The output shaft is configured to rotate forward and reverse by forming a single clutch and selectively meshing this sleeve with one of the gears.

In this type of shift device, a detent mechanism is provided to hold the sleeve in a neutral position where it does not mesh with any gear.

In a conventional detent mechanism, the inner end of a detent pin that passes through the sleeve in the radial direction is inserted into a recess provided on the outer surface of the output shaft, and an annular spring attached to the outer circumference of the sleeve moves the detent pin inwards ( There is a device that presses in the direction of the output shaft (Japanese Patent Application Laid-Open No.
-64392, JP-A-57-160796).

However, in this case, there is a problem in that the centrifugal force applied to the detent pin increases significantly during high-speed operation, making it easier for this pin to escape from the recess, and deteriorating the detent function during high-speed operation.

It has also been proposed to provide a plunger for moving a sleeve that moves back and forth within the output shaft with a ball that projects radially outward, and to engage this ball in a recess formed on the inner surface of the output shaft (Japanese Unexamined Patent Publication No. 57-111). −
84296, U.S. Pat. No. 3,919,964). However, this applies a radial projecting force to the ball by pressing a retainer with a conical or spherical surface from one side of the ball, so the shift operation force in the forward direction and the shift operation force in the reverse direction are different. It will not be evenly distributed and the operation feeling will be poor. Furthermore, when the torsion spring of the shift shaft is used to engage the dog clutch, there is a problem in that gear noise is likely to occur if the escape force of the detent mechanism in either forward or reverse rotation is insufficient.

The present invention was made in view of these circumstances, and it ensures that the detent mechanism operates reliably even at high speeds.
The purpose of the present invention is to provide a shift device for a marine propulsion unit that can equalize the shift operation force in both forward and reverse directions, is effective in improving the operating feeling and preventing gear noise, and is also suitable for downsizing the device. do.

In order to achieve this object, the present invention presses the ball held by the plunger from both sides with substantially symmetrical tapered surfaces, so that the ball is inserted into a recess provided on the inner surface of the output shaft. That is, this purpose is to provide a forward rotation gear and a reverse rotation gear that are freely rotatably held on an output shaft and rotated in opposite directions by the engine, and a gear that slides in the axial direction on the output shaft between these two gears. A sleeve that meshes with the output shaft to form a clutch, a plunger that moves forward and backward within the output shaft to move the sleeve, and a detent mechanism that removably locks the sleeve in a neutral position, wherein the detent mechanism includes a recess provided on the inner surface of the output shaft, a pair of retainers that are internally installed in the plunger and are arranged so that substantially symmetrical tapered surfaces face each other, and one of the retainers that is disposed on the axis of the plunger and that slides. a shaft that freely moves through the shaft and has one end fixed to the other retainer, and a coil spring that is compressed between the other end of the shaft and the back surface of the one retainer and urges both the retainers to approach each other. and a ball held between the tapered surfaces and biased to protrude through the plunger in a radial direction, the ball engaging the recess at a neutral position of the sleeve. A shift device for a marine propulsion unit, characterized by
This is achieved by Based on the example shown below,
The present invention will be explained in detail.

FIG. 1 is a side view showing an outboard motor as an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of its main parts, and FIG.
This figure and FIG. 4 are a sectional view taken along the line -- in FIG. 3 and an explanatory diagram of the operation taken along the line -, and FIG. 5 is an explanatory diagram of the operation in the normal rotation (advance) state.

In FIG. 1, reference numeral 10 is a propulsion unit that includes an upper casing 12, a lower casing 14, and an engine (not shown), and the engine is covered with a cowling 16. The propulsion unit 10 is attached to a clamp bracket 20 via a swivel bracket 18 so as to be rotatable left and right. The clamp bracket 20 is attached to the stern plate 2
It is fixed at 2. 24 is a reversing handle.

26 is an output shaft disposed substantially horizontally within the lower casing 14, 28 is a propulsion propeller attached to this output shaft 26, and 30 is a group of forward/reverse switching gears. As shown in FIG. 2, this gear group 30 includes gears 32 and 34 for forward rotation and reverse rotation, which are rotatably mounted on the output shaft 26.
2 and 34 are drive shafts 36 driven by the engine;
They mesh with a small gear 38 fixed to and are rotated in opposite directions. 40 and 42 are bearings that rotatably support the gears 32 and 34 within the lower casing 14.

A sleeve 44 is splined to the output shaft 26 between the gears 32 and 34, and is slidable in the axial direction. This sleeve 44 has pawls 46 and 48 projecting in the axial direction, and both gears 3
2 and 34 have claws 5 opposite to these claws 46 and 48.
0, 52 are formed, and these pawls 46, 50 and 48, 52 form dog clutches, respectively. 54 is the propeller 2 into the output shaft 26
The plunger is inserted from the side opposite to 8, and has a substantially cylindrical shape with one end open. The output shaft 26 has a long hole 56 formed in the axial direction, and a plunger 54
A pin 58 passing through one end of the pin 58 passes through the elongated hole 56 and the sleeve 44, and faces an annular groove 60 provided on the outer periphery of the sleeve 44. A coil spring 62 is attached to the annular groove 60 to prevent the pin 58 from falling off. As a result, the sleeve 44 is attached to the plunger 5.
4 within the range of the elongated hole 56.

The plunger 54 has a built-in detent mechanism. The day tent mechanism includes a ball 60 that penetrates the cylindrical portion of the plunger 54 and is movable in the radial direction.
A pair of retainers 6 that are located inside the plunger 54 and have substantially symmetrical conical tapered surfaces that sandwich the balls 60.
2,64. The retainers 62 and 64 are slidably supported on one shaft 66, one retainer 62 is in contact with one end of this shaft 66, and there is a space between a washer locked at the other end and the other retainer 64. The spring 68 is compressed. As a result, the retainer 62,
64 presses the ball 60 from both sides with equal force. Further, a recess 70 is formed on the inner surface of the output shaft 26, and the ball 60 is formed in the neutral position of the sleeve 44.
engages in this recess 70.

Therefore, this detent mechanism holds the sleeve 44 in the neutral position where the ball 60 is engaged in the recess 70, and when a predetermined axial load is applied to the plunger 54, the ball 60 compresses the spring 68 and the retainer 62, 64 is pushed open, pushed toward the center, and escapes from the recess 70 (see FIG. 5). Since the tapered surfaces of the retainers 62 and 64 are substantially symmetrical, the load required to dislodge the ball 60 from the recess 70 is substantially the same in both directions.

A cam follower 72 is housed in a cam follower loading chamber 74 in the lower casing 14, and moves back and forth parallel to the output shaft 26. One end of the cam follower 72 is rotatably connected to the plunger 54. That is, the plunger 54 has a small diameter portion 7.
A disk-shaped large diameter portion 78 is formed through the cam follower 72, while a recess 80 having a U-shaped cross section is formed in the cam follower 72.
is formed (see FIG. 4), and by engaging the large diameter portion 78 into this recess 80, the two are connected.

Reference numeral 82 denotes a shift shaft, which passes through the inside of the bearing cylinder of the swivel bracket 18, and has a shift lever 84 fixed to its upper end (FIGS. 1 and 2). The lower end of the shift shaft 82 extends into the cam follower loading chamber 74, and a substantially diamond-shaped cam 86 is spline-coupled thereto. This cam 86 is attached to the cam follower 72.
A substantially arc-shaped cam surface 88 is formed on which the cam 86 slides, and as the cam 86 rotates, the cam follower 72 moves forward and backward in the axial direction (FIG. 4). Furthermore, the shift lever 84
can be fixed at neutral (N), forward (forward, F), and reverse (reverse, R) positions.

Next, the operation of this embodiment will be explained. In the neutral position (N) of the shift lever 84, the ball 60 of the detent mechanism engages the recess 70, and the sleeve 44 does not mesh with either of the gears 32, 34. Therefore, the rotation of the engine is not transmitted to the output shaft 26.

When the shift lever 84 is rotated to the normal rotation position F, the cam 86 is twisted counterclockwise as shown in FIG. . At this time, due to the torsion spring force stored in the shift shaft 82, the cam follower 72, plunger 54, and sleeve 44 move toward the forward rotation gear 32 with a snap action, and the pawls 46 and 50 mesh with each other. Therefore, the rotation of the gear 32 is transmitted to the propeller 28 via the sleeve 44 and the output shaft 26, and the ship moves forward.

When the shift lever 84 is rotated to the reverse rotation position R, the sleeve 44 moves to the reverse rotation gear 34, contrary to the normal rotation.
The propeller 28 rotates in reverse. Since the detent mechanism escapes from its neutral position in both forward and reverse directions with approximately the same set load, the loads at which the sleeve 44 meshes with the gears 32 and 34 are also approximately the same. Therefore, the shift operation force in both the forward and reverse directions is approximately the same, and the moving speed of the sleeve 44 is also approximately the same, making it possible to prevent gear noise during operations in both the forward and reverse directions.

Note that according to this embodiment, the retainers 62 and 64 are
Although it is possible to press evenly with two springs 68, the present invention has two springs 68.
The two retainers may be pressed separately by two springs having approximately equal spring force. Furthermore, in an inboard/outboard motor or the like in which a shift mechanism is provided on a drive shaft that passes approximately perpendicularly through the upper and lower casings, the drive shaft naturally corresponds to the output shaft of the present invention.

As described above, in the present invention, the set load of the detent mechanism is made to be approximately the same in both the forward and reverse directions, so the moving speed and load when the sleeve meshes with the forward and reverse gears are equalized, and the load in the forward and reverse directions is equalized. - Prevents gear noise when operating in both reverse and reverse directions. Furthermore, since the difference in operating force between forward and reverse rotation is small, the operating feel is also good. Furthermore, since both retainers are biased toward each other by a coil spring disposed on the axis of the plunger, large changes in biasing force due to centrifugal force do not occur even when the output shaft rotates at high speed. Stable operation is possible even at high speeds. Further, since the coil spring is disposed in the axial direction of the plunger, even if a long coil spring is accommodated to obtain a sufficient biasing force, the diameter of the plunger does not become large, and the device is suitable for downsizing.

[Brief explanation of drawings]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is an enlarged sectional view of the main part thereof, Fig. 3 is a sectional view taken along the - line in Fig. 2, and Figs. FIG. 2 is a cross-sectional diagram illustrating the operation. 10... Propulsion unit, 26... Output shaft, 3
2, 34... Forward rotation and reverse rotation gear, 44...
Sleeve, 54...plunger, 60...ball, 62, 64...retainer, 70...recess.

Claims (1)

[Scope of Claims] 1. Forward rotation and reverse rotation gears that are freely rotatably held on the output shaft and rotated in opposite directions by the engine, and a gear that slides in the axial direction on the output shaft between these two gears. The gear includes a sleeve that forms a meshing clutch with the gear, a plunger that moves forward and backward within the output shaft to move the sleeve, and a detent mechanism that removably locks the sleeve in a neutral position, The detent mechanism includes a recess provided on the inner surface of the output shaft, a pair of retainers that are internally installed in the plunger and arranged so that substantially symmetrical tapered surfaces face each other, and one of the retainers that is arranged on the axis of the plunger. A shaft that slidably passes through the shaft and has one end fixed to the other retainer, and a shaft that is compressed between the other end of the shaft and the back surface of the one retainer and urges both the retainers to approach each other. a coil spring; and a ball held between the tapered surfaces and biased to protrude through the plunger in a radial direction, such that the ball engages in the recess at a neutral position of the sleeve. A shift device for a marine propulsion unit characterized by: