JPH0417880Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a shift fork of a gear mechanism, and more specifically, to a shift fork of a gear mechanism in which a sleeve is moved to switch the power transmission path. It is about improvement.

[Conventional technology]

Part-time four-wheel drive vehicles that can switch from four-wheel drive, which drives the front and rear tires, to two-wheel drive, which drives only the rear tires, are equipped with a power transmission mechanism for switching. When in four-wheel drive,
The engine's output is transmitted to the transmission, which then drives the rear tires via the propeller shaft, while the power distributed from the transfer also drives the front tires. Therefore, in the case of two-wheel drive, power distribution to the front tires is cut off at the transfer, and only the rear tires are driven.

The transfer is provided with a power transmission path switching mechanism for switching from four-wheel drive to two-wheel drive and vice versa.
In this switching mechanism, a sleeve with internal teeth is moved in the axial direction by a shift fork fitted into a groove on its outer periphery, and a power transmission path is determined depending on the position of the sleeve. In other words, the external teeth formed on two adjacent rotating bodies located on the transmission side and the driven side mesh with the internal teeth of the sleeve, and power transmission is connected via the tooth surfaces in the engaged state. Also, when the sleeve is removed from one of the rotating bodies, power transmission is interrupted.

By the way, when the power of the engine is being transmitted to the tires, one tooth surface of the rotating bodies and sleeves that are in mesh are in contact with each other, and when engine braking is being applied, the opposite tooth surface is in contact with each other. Power is transmitted in a counter-current manner. However, if the engine power does not directly contribute to the rotation of the tires, that is, if the rotational speeds of the two rotating bodies connected by the sleeve match and the engine power is not transmitted, each rotating body The sleeve that meshes with is in a floating state.

At that time, the sleeve was not transmitting power and was suspended in the air relative to each rotating body, and as a result, the sleeve, whose axial position was maintained by the frictional force of contact with the rotating body, was no longer axially constrained. This makes it possible to displace it.
In such a case, the sleeve vibrates in the axial direction, and the vibration causes the sleeve to hit the shift fork, causing repeated interference noise between the groove wall surface of the sleeve and the side surface of the shift fork.

Since it is not desirable to generate such interference noise, measures have been taken to prevent it.
An example of this is described in Japanese Utility Model Application Publication No. 58-2031. In this shift fork, resin is applied to the tip claw of the Japanese finger and the meeting area of both fingers, so that even if vibrations occur due to floating of the sleeve, the shift fork will not move through the resin. It comes into contact with the groove of the sleeve and can suppress interference noise.

[The problem that the idea attempts to solve]

In the example of the shift fork mentioned above, the resin that prevents interference noise is fixed to the mounting hole of the shift fork by welding, etc., so when the resin wears out and the interference noise suppression function deteriorates, the resin can be easily replaced. There is a problem that cannot be replaced. Of course, replacing the shift fork itself is not preferable because it increases the burden on the user.

By the way, Japanese Patent Publication No. 56-33725 also describes a semi-circular shift fork having claws at both ends which are fitted into the outer circumferential groove of the sleeve.
A punched hole is provided at each end of the shift fork, and a U-shaped pawl member made of a wear-resistant resin material is engaged with the punched hole. The claw members are engaged with the punched holes through protrusions formed at the tips of the inner surfaces of the U-shaped sides, and are attached so as to sandwich the shift fork body by the elasticity of the claw members. In this state, when the claw member is fitted into the outer circumferential groove of the sleeve, the outer surfaces of the U-shaped back and sides correspond to the side walls and bottom of the outer circumferential groove, making it difficult to withstand sliding contact with the sleeve. become able to.

However, as described above, the sleeve vibrates in the axial direction, and due to the vibration, the sleeve hits the shift fork, and interference between the groove wall surface of the sleeve and the side of the claw member of the shift fork still occurs. In such a case, the sleeve may tilt slightly and its attitude relative to the shift fork may change. At this time, as the corner portion of the claw member repeatedly hits the groove wall surface of the sleeve, the corner portion of the U-shaped claw member wears unevenly. In addition, cracks may occur at the intersection of the back and side portions of the claw member, causing the claw member to separate. The separated portion is just the above-mentioned protrusion that is stuck in the punched hole, and there is a possibility that the pawl member may fall off from the shift fork body.

The present invention was created in view of the above problems,
The purpose is to simplify the replacement of the vibration prevention elastic body attached to the shift fork, and to
Even if the sleeve floats, interference noise with the shift fork can be prevented, and even if the pawl member is damaged during repeated contact with the groove of the sleeve, the shift fork body of the pawl member can be prevented. To provide a shift fork of a gear mechanism which can maintain a state of being held against the gear and avoid unexpected situations such as falling off.

[Means to solve the problem]

This invention is applied to a shift fork used in a device that connects or disconnects two adjacent rotating bodies by moving a sleeve through a groove formed on the outer periphery to switch the power transmission path in a gear mechanism. Applicable.

Its characteristics are as shown in Figure 1.
A mounting hole 2 is formed in the shift fork 1 at a portion to be fitted into the groove 5 of the sleeve 4.
An elastic body 3 for vibration prevention, which is attached to the shift fork 1, is divided into two parts so as to sandwich the shift fork 1 therebetween. One divided body 3 of the divided elastic body 3
In A, a fitting part 9 that is fitted into the mounting hole 2 projects from a flange part 8 formed along one surface of the shift fork 1, and the fitting part 9
An internal space 9a is formed in the elastic body 3, and the other divided body 3B of the elastic body 3 has a fitting part that is tightly attached to the internal space 9a from a flange part 10 formed along the other surface of the shift fork 1. 11 is provided protrudingly. The elastic body 3 can be attached to the shift fork 1 by fitting both the fitting parts 9 and 11 of the divided bodies 3A and 3B into the attachment hole 2 so that they fit into each other from both sides of the attachment hole 2. That's what I did.

[Effect]

One divided body 3A of the elastic body 3, which is divided into two parts so as to be attached with the shift fork 1 in between, is
The fitting part 9 of the shift fork 1 is fitted into the attachment hole 2, leaving the flange part 8 formed along one surface of the shift fork 1. And the other divided body 3B
, leaving the flange portion 10 formed along the other surface of the shift fork 1, and inserting the fitting portion 1 into the shift fork 1.
1 is fitted tightly into the internal space 9a of the fitting portion 9.

In this way, the elastic body 3 can be easily attached to the shift fork 1 by fitting both the fitting parts 9 and 11 of the divided bodies 3A and 3B into the mounting hole 2 from both sides of the mounting hole 2. It can be attached to. Since the integrated divided bodies 3A and 3B are fitted into the groove 5 on the outer periphery of the sleeve 4, the divided bodies 3A and 3B do not come off from the shift fork 1.

The elastic body 3 has a groove 5 provided on the outer periphery of the sleeve 4.
Although the shift fork 1 is fitted into the sleeve 4 with an extremely small gap, the inner periphery of the sleeve 4 into which the shift fork 1 is fitted has a tooth profile, and the sleeve 4 is fitted into the outer periphery of the two rotating bodies located on the transmission side and the driven side. are engaged with each other, and by moving the sleeve 4 in the axial direction by the shift fork 1, the adjacent rotating bodies are brought into a transmission state or a cutoff state. When the sleeve 4 is fitted to both rotating bodies and the rotational speeds of both rotating bodies become the same, the sleeve 4 floats, but at that time, even if the sleeve 4 moves in the axial direction or tries to vibrate, The elastic body 3 interposed so as to slightly protrude from the side of the shift fork 1 prevents interference noise between the sleeve 4 and the shift fork 1 from being generated.

Meanwhile, during operation, sleeve 4 and shift fork 1
If there is a change in the relative position between the sleeve 4 and the elastic body 3, the groove wall surface of the sleeve 4 and the side portions of the elastic body 3 may interfere with each other, and uneven wear may occur at the corners of the elastic body 3. Even if such a situation occurs, since both the divided bodies 3A and 3B are integrated through the mounting hole 2, the elastic body 3
If it falls off Shift Fork 1, nothing will happen.

[Effect of idea]

Between the shift fork and the sleeve, an elastic body for vibration prevention that is divided into two parts that can be fitted to each other is fitted from both sides of the mounting hole drilled in the shift fork, so that the elastic body The installation work is easily performed, the time and effort required for replacement work is significantly reduced, and uneconomical problems such as having to replace the shift fork itself are also avoided.

Since the elastic body is fitted into the groove of the sleeve, even if the sleeve that connects the two rotating bodies on the transmission side and the driven side floats, the elastic body absorbs or prevents the axial displacement and vibration of the sleeve. can do. Therefore, the sleeve does not come into direct contact with the shift fork, and interference noise is prevented from occurring. This eliminates the occurrence of the sleeve collapsing against each rotating body, and eliminates harsh noises.

Furthermore, even if the elastic body wears unevenly, the two divided bodies, which are integrated through the attachment hole, will never fall off the shift fork.

〔Example〕

EMBODIMENT OF THE INVENTION Below, the shift fork of the gear mechanism of this invention will be explained in detail based on the Example.

The shift fork 1 shown in FIG. 1 has a mounting hole 2 drilled in the part to be fitted into the outer circumferential groove 5 of the sleeve 4, and a rubber body or a resin body divided into two parts as shown in the figure is inserted into the mounting hole 2. The elastic bodies 3A and 3B are
Can be installed by sandwiching shift fork 1. The elastic bodies 3A and 3B are formed into a fitable shape as described below, and are easily integrated. The inner peripheral part 1a of the shift fork 1 and the elastic body 3 fitted into the groove 5 formed along the outer periphery 4a of the sleeve 4 are connected to the outer surfaces 3a, 3 of the divided bodies 3A, 3B.
b is fitted into the groove wall surface 5a with an extremely narrow gap close to contact therebetween.

The shift fork 1 moves the sleeve 4 in the direction of the arrow 6, and is formed into a substantially semicircular arc shape as shown in FIG. ing. In the above-mentioned mounting hole 2 in such a shift fork 1, the tips of the left and right fingers 1b are located on the inner circumferential surface 1.
The holes are drilled at the positions where they meet along a. Note that the inner peripheral portion 1a is surrounded by maintaining an appropriate distance between the inner peripheral portion 1a and the groove bottom surface 5b shown in FIG.
The sleeve 4 can be moved by directly pressing the groove wall surface 5a on the outer surfaces 3a and 3b of A and 3B.

One of the divided bodies 3A of the elastic body 3 consists of a flange part 8 and a hollow fitting part 9, and an air vent hole 8a is formed at the center of the flange part 8 formed along one surface of the shift fork 1. The divided body 3A is provided so as to communicate with the internal space 9a of the hollow body.
When integrating the divided body 3B, the internal space 9a
Care has been taken to allow air to escape.
The outer periphery 9b of the fitting part 9 is formed with a slightly larger dimension so as to be slightly press-fitted into the inner surface 2a of the mounting hole 2, and enhances the effect of preventing the elastic body 3 from coming off when it is fitted and integrated with sufficient surface pressure. ing.

The inner periphery 9c is dimensioned so that it can be easily tightened with respect to the outer periphery 11a when the fitting portion 11 of the divided body 3B described below is inserted and integrated. On the other hand, the divided body 3B consists of a flange portion 10 formed along the other surface of the shift fork 1 and a cylindrical fitting portion 11, and when the outer periphery 11a of the fitting portion 11 is fitted into the internal space 9a. , are in close contact with the inner periphery 9c and contribute to the integration of the divided body 3A and the divided body B.

As can be seen from FIG. 4, the sleeve 4 shown in FIG. 3 is formed in an annular shape, and has teeth carved on its inner circumferential surface 4b, which are integrally attached to the side of a sprocket 23 that transmits power to, for example, a front tire. The external teeth of the rotating body 12 on the driven side and the transfer shaft 2 on the transmission side
It engages with external teeth carved on a rotating body 13 attached to the rotating body 1 by spline fitting, and both rotating bodies 12, 13
This makes it possible to transmit power between the two. Further, this sleeve 4 is moved in the direction of the arrow 6 mentioned above by the operation of the shift fork 1 in conjunction with the movement of a shift rod (not shown). Therefore, the engine output is transmitted or cut off from the rotating body 13 to the sprocket 23, and the front tires can be driven or not driven.

In the transfer 14 shown in FIG. 4, a transmission shaft 15 thereof is connected to an output shaft 16 of a transmission connected to an engine. Transmission shaft 15
A gear body 17 is formed on the gear body, and a reduction gear body 18 that meshes with the tooth body 17 is installed at an outer position. A floating gear 20 is provided which meshes with the tooth body 19 and is rotatable relative to the transfer shaft 21.

End 17a of tooth body 17 and end 20 of gear 20
a and the end 21a of the transfer shaft 21 are respectively provided with external teeth, and each tooth surface has a tooth surface having the same pitch circle so that each tooth body can engage with the internal teeth of a sleeve 22 similar to the sleeve 4 described above. It's summery. The sleeve 22 in the position indicated by the solid line causes the reduction gear body 18 to idle and can transmit the rotation of the transmission shaft 15 to the transfer shaft 21 without decelerating it. When the sleeve 22 is moved to the position indicated by the two-dot chain line, the speed is reduced by the reduction gear body 18 and the gear 20, and the speed is transmitted to the transfer shaft 21.

A relatively rotatable sprocket 23 is fitted onto the transfer shaft 21, and is engaged with a chain 24 that extends between the sprocket 23 and a sprocket (not shown) that drives the front tires. At the end of the sprocket 23,
There is a rotating body 12 having external teeth that can engage with the internal teeth of the sleeve 4 described above, and similar external teeth are formed on the outer periphery of the rotating body 13 fixed to the transfer shaft 21. When the sleeve 4 is in the solid line position, the tooth surfaces of the rotating bodies 13 and 12 are engaged with the sleeve 4.
Therefore, the power from the transfer shaft 21 is transmitted to the chain 24 via the rotating body 13, the sleeve 4, the rotating body 12, and the sprocket 23. As a result, the front tires are driven, resulting in a four-wheel drive state. A flange 26 is fixed to the tip of the transfer shaft 21, and the rear tires are constantly driven by a propeller shaft (not shown).

In the gear mechanism having such a configuration, the shift fork can move the sleeve 4 as described below, and can also prevent the generation of interference noise during floating.

When the engine output is transmitted to the output shaft 16 shown in FIG. 4, the power is transmitted to the transmission shaft 15 of the transfer 14 via the shaft coupling 27. When the sleeve 22 is in the position indicated by the solid line, the rotational power is directly transmitted to the transfer shaft 21 as described above, and its reduction ratio is 1. On the other hand, when the sleeve 22 is moved to the position indicated by the two-dot chain line, the speed is reduced via the reduction gear body 18, and the transfer shaft 21 has a reduction ratio of 1.
The above low rotation and high torque power is transmitted.

In the case of four-wheel drive, when the sleeve 4 is in the position shown by the solid line, the sprocket 23 is driven from the rotating body 13 via the sleeve 4, and the front tire is driven by the chain 24 that meshes with the sprocket 23. On the other hand, the rear tires are also driven via a flange 26 fixed to the transfer shaft 21 and a propeller shaft. 2
In the case of wheel drive, the sleeve 4 is moved to the position indicated by the two-dot chain line, the connection between the rotating body 13 and the sprocket 23 is interrupted, and the drive of the front tires is stopped.

In the above-mentioned four-wheel drive, the sleeve 4 has teeth on its inner peripheral surface 4b that mesh with the external teeth of the rotating body 13 and the external teeth of the rotating body 12 integrated with the sprocket 23, so that the output of the engine is transferred to the front tires. to communicate. Now, when the inertial speed of the vehicle body becomes the same as the driving speed of the engine and the rotational speeds of both rotating bodies 12 and 13 match, a floating phenomenon occurs in the sleeve 4. At this time, power is not transmitted between the external teeth of the rotating body 13, the internal teeth of the sleeve 4, and the external teeth of the rotating body 12. As a result, there is no element that restricts the axial displacement of the sleeve 4, and the sleeve 4 appears to be floating in the air.

In that case, the sleeve 4 tilts or vibrates in the axial direction. However, the sleeve 4 shown in FIG.
In the groove 5 provided on the outer periphery 4a of the divided bodies 3A, 3
The elastic body 3 can be attached to the shift fork 1 by fitting the fitting portions 9 and 11 of B into the attachment hole 2 so that they fit into each other from both sides of the attachment hole 2. sleeve 4
Even if the shift fork 1 tries to vibrate, interference with the shift fork 1 due to it is avoided. Furthermore, since the shift fork 1 is fitted into the groove 5 with a slight narrow gap, the operation of the sleeve 4 is not hindered when the shift fork 1 moves the sleeve 4.

To attach the elastic body 3 to the shift fork 1, insert the elastic body 3A into the mounting hole 2, bring the flange part 8 into contact with one side surface of the shift fork 1,
The inner surface 2a of the mounting hole 2 and the outer periphery 9b of the fitting part 9 are brought into close contact. Subsequently, the fitting part 11 of the elastic body 3B is inserted into the internal space 9a of the fitting part 9 of the elastic body 3A,
The flange portion 10 is brought into contact with the other side surface of the shift fork 1. At this time, the air in the internal space 9a escapes from the air vent hole 8a and can be easily inserted. The inner surface 9c of the fitting portion 9 and the outer periphery 11a of the fitting portion 11 are tightly tightened, making it difficult for the integrated elastic body 3 to come off.

Incidentally, if the relative posture between the sleeve 4 and the shift fork 1 changes during operation of the gear mechanism, the groove wall surface of the sleeve 4 and the side part of the elastic body 3 will interfere, causing the corners of the elastic body 3 to Although uneven wear may occur, both split bodies 3A and 3B are attached through the mounting hole 2.
Since these are integrated, it is possible to prevent the elastic body 3 from falling off the shift fork 1.

Although the above description has been made with reference to the case where the sleeves 4 and 22 in the transfer gear 14 are moved by the shift fork 1, the shift fork 1 of the present invention is applicable not only to the above-mentioned applications but also to general use. It can also be widely adopted in switching mechanisms such as transmissions.

[Brief explanation of drawings]

Figure 1 is a sectional view of the main parts of the shift fork of the gear mechanism of the present invention, Figure 2 is an external view of the shift fork,
Figure 3 is a sectional view of the sleeve and shift fork at the installation position, and an enlarged view of part A in Figure 4.
The figure is a longitudinal sectional view of a transfer to which the present invention is applied. 1...Shift fork, 2...Mounting hole, 3...
Elastic body, 3A, 3B...Divided body, 4, 22...Sleeve, 4a...Outer periphery, 5...Groove, 8...Flange portion, 9...Inset portion, 9a...Inner space, 10...
...Flange part, 11... Fitting part, 12, 13...
Rotating body.

Claims (1)

[Claims for Utility Model Registration] Used in a device that connects or disconnects two adjacent rotating bodies by moving a sleeve through a groove formed on the outer periphery to switch the power transmission path in a gear mechanism. In the shift fork, a mounting hole is formed in the shift fork at a portion of the sleeve that is inserted into the groove, and an elastic body for vibration prevention is attached to the mounting hole so as to sandwich the shift fork. The elastic body is divided into two parts, and one of the divided elastic bodies has a fitting part that is fitted into the above-mentioned mounting hole protruding from a flange part formed along one surface of the shift fork. An internal space is formed in the fit-in part, and the other divided body of the elastic body extends from the flange part formed along the other surface of the shift fork.
A fitting portion is provided to protrude tightly into the internal space, and the elastic body is fitted into the mounting hole so that both fitting portions of the split body are fitted into each other from both sides of the mounting hole. A gear mechanism shift fork characterized by the fact that a shift fork can be attached.