JPH0628355U - Reverse gear squeal prevention device for manual transmission - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a reverse gear squeal prevention device for a manual transmission, which improves gear entry performance while preventing gear squeal and has small power loss during reverse travel. [Structure] A sleeve that moves in the axial direction when shifting to the reverse stage, a forward gear adjacent to the moving direction side of the sleeve, and elastically deformable in the radial direction attached to the sleeve side end portion of the forward gear. And a synchronizer key arranged on the inner peripheral side of the sleeve. When the sleeve moves in the axial direction, the end of the synchronizer key first presses the friction member to generate a frictional force between the synchronizer key, the friction member and the forward gear, and the further movement of the sleeve causes friction. The member fits on the inner surface side of the synchronizer key.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversing gear squeal prevention device for a manual transmission, which prevents gear squeal when shifting to a reverse gear.

[0002]

[Prior art]

 Conventionally, as a reverse gear squeal preventing device of this type, as described in JP-A-59-9318, a sleeve that moves when a shift lever is operated in a backward direction and a side of the sleeve in the moving direction. It has been proposed that a synchronizing member is configured by arranging a synchronizing member (for example, a synchronizer ring) between the advancing gear adjacent to the.

In this case, a conical clutch surface is provided at the end of the third speed gear, which is a forward gear, and the synchronizer ring arranged on this clutch surface is pushed by the sleeve, whereby the synchronizer ring and the conical ring are pushed. A frictional force is generated between the sleeve and the clutch surface to synchronize the sleeve with the third speed gear. In other words, the braking force is applied to the input shaft that rotates integrally with the sleeve. By engaging the reverse gear with the input shaft stopped in this way, gear noise is prevented.

The characteristic of the shift load in this structure is shown by a broken line in FIG. That is, in the initial stage of the stroke of the sleeve, the load increases rapidly, and when it passes the maximum point corresponding to the key detent load, the load decreases, and when the point a, which is the beginning of meshing of the reverse gear, is passed, the load gradually decreases. The load decreases. Point b is the end point of the movement of the sleeve, and c is the end point of the shift of the reverse shift fork.

[0005]

[Problems to be solved by the device]

 However, as is clear from FIG. 1, at the beginning of meshing of the reverse gear (point a), the shift load is still considerably high, which increases the gear-discharging force at the time of reverse shift and enters the reverse gear. There was a drawback that performance deteriorated significantly. Further, if a synchronizer for preventing reverse gear squeal is provided between the gear for the third speed and the sleeve as described above, the difference between the gear ratio of the reverse gear and the gear ratio of the third gear during the reverse traveling. Only there is slippage in the synchronizer (specifically between the synchronizer ring and the conical clutch surface). Further, since the shift load (braking force) at the shift end point c is constantly acting on the synchronizer during the backward running, there is a problem that the frictional resistance causes power loss. Therefore, an object of the present invention is to provide a reverse gear squeal prevention device for a manual transmission that improves gear entry performance while preventing gear squeal, and that reduces power loss during reverse travel.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a sleeve that moves in the axial direction when shifting to a reverse stage, a forward gear that is adjacent to the moving direction side of the sleeve, and a sleeve-side end portion of the forward gear. When the sleeve moves in the axial direction, the sleeve or a member that rotates integrally with the sleeve presses the side surface of the friction member protruding from the sleeve side end portion. A frictional force is generated between the sleeve, the friction member, and the forward gear, and the friction member is embedded in the sleeve side end portion by the further movement of the sleeve.

[0007]

[Action]

 In the initial stage of the shift to the reverse stage, the end of the sleeve or the member that rotates integrally with the sleeve presses the friction member against the forward gear, so that a frictional force is generated between the sleeve, the friction member, and the forward gear. This frictional force exerts control on the shaft that rotates integrally with the sleeve, and by engaging the reverse gear with the shaft stopped, gear noise can be prevented. Further shifting causes the friction member to be buried in the sleeve-side end of the forward gear, so that the frictional force between the sleeve and the friction member or between the friction member and the forward gear is almost eliminated. Therefore, at the beginning of meshing of the reverse gear, the braking force on the shaft that rotates integrally with the sleeve is released, and the performance of entering the reverse gear can be improved. At the end point of the shift, the braking force is much smaller than before, so there is less power loss when traveling backward.

[0008]

【Example】

 FIG. 2 shows an example of a manual transmission having a reverse gear squeal preventing device according to the present invention. In the figure, the input shaft 1 is driven by the engine via a clutch (not shown). On the input shaft 1, a fifth speed gear 2, a third speed gear 3 and a fourth speed gear 4 are rotatably supported in order. A 3-4 speed switching synchronizing device 5 is provided between the third speed gear 3 and the fourth speed gear 4, and 5 is provided between the third speed gear 3 and the fifth speed gear 2. A speed switching synchronizer 6 is provided.

The synchronizers 5 and 6 are both inertia lock type key synchronizers. To explain the synchronizer 6 as an example, a clutch hub 7 spline-fitted to the input shaft 1 and an outer periphery of the clutch hub 7 are provided. A sleeve 8 fitted by a spline, a shift fork 9 engaged with an outer circumferential groove of the sleeve 8, a synchronizer ring 10 that comes into contact with a cone surface 2a formed on the fifth speed gear 2 to perform a clutch action, and a rear surface. The protrusion is engaged with the sleeve 8 and is composed of a synchronizer key 11 fitted in the groove of the clutch hub 7 and a synchronizer spring 12 which supports the synchronizer key 11 from the inside. In a normal synchronizer, a pair of right and left synchronizer springs 12 are provided, but in this embodiment, only one is provided on the fifth speed gear side, and the third speed gear side of the synchronizer key 11 is provided on a boss portion described later. It is supported by 3a. The sleeve 8 is configured to move to the left in FIG. 2 when the shift lever is shifted to the fifth speed direction, and to move to the right in FIG. 2 when the shift lever is shifted to the reverse direction. .

As shown in FIG. 3, a cylindrical boss portion 3a is projectingly provided on the left side portion of the third speed gear 3, and one peripheral groove 3b is formed on the outer periphery of the boss portion 3a. There is. A substantially C-shaped steel friction member 12 which is elastically deformable in the radial direction is engaged with the circumferential groove 3b, and the friction member 12 is capable of projecting and retracting with respect to the circumferential groove 3b. The inner diameter of the envelope circle formed by the inner surface of the right end portion of the synchronizer key 11 is set to be substantially the same as the outer diameter of the boss portion 3a of the third speed gear 3, and the concave portion 11a is formed on the inner surface of the central portion of the synchronizer key 11. Are formed. The outer diameter of the friction member 12 in the free state is larger than the inner diameter of the right end portion of the synchronizer key 11 and is substantially equal to the inner diameter of the recess 11a of the synchronizer key 11.

The operation of the reverse gear squeal preventing device having the above structure, particularly the synchronizing device 6, will be described. First, this manual transmission has a shift pattern as shown in FIG. 4. When the shift lever is shifted to the fifth speed direction, the sleeve 8 moves to the left in FIG. 2, and the sleeve is moved by a well-known synchronous action. 8 (input shaft 1) and the fifth speed gear 2 relative rotation difference is eliminated, and the sleeve 8 is meshed with the fifth speed gear 2 clutch gear 2b. As a result, the fifth speed state is reached.

On the other hand, when the shift lever is shifted in the reverse (R) direction, the sleeve 8 moves to the right in FIG. Along with this, the synchronizer key 11 engaged with the sleeve 8 also moves to the right, and the end face of the synchronizer key 11 presses the friction member 12 against the side wall of the circumferential groove 3b of the third speed gear 3. Therefore, a frictional force is generated between the synchronizer key 11, the friction member 12, and the third speed gear 3, and the sleeve 8 and the third speed gear 3 are synchronized with each other. At the time of shifting to the reverse gear, the third shaft gear 3 is also stopped because the wheels are stopped, but the input shaft 1 may be rotating due to inertia. However, as the sleeve 8 synchronizes with the third speed gear 3 as described above, a braking force is applied to the input shaft 1 and the input shaft 1 also stops. If the input shaft 1 is stopped in this manner and the gear is shifted to the reverse gear, the reverse gear (not shown) can be smoothly meshed with the gear to prevent gear noise.

When the shift lever is further shifted in the backward direction, the synchronizer key 11 bends the friction member 12 in the inner diameter direction, so that the friction member 12 eventually moves to the synchronizer key 11 as shown in FIG. 3B. It fits into the recess 11a on the inner surface. In this state, almost no frictional force is generated between the synchronizer key 11 and the friction member 12 or between the friction member 12 and the third speed gear 3, so that the synchronizer key 11 (sleeve 8) cannot be controlled. Almost no power is added. Therefore, as shown by the solid line in Fig. 1, the shift load becomes considerably small at the beginning of meshing of the reverse gear (point a), the gear removal force at the time of reverse shift is also small, and the entry performance to the reverse gear is better than before. Can be greatly improved. Also, at the shift end point (point c), the shift load (braking force) is much smaller than before, so even if there is a difference between the gear ratio of the forward gear and the gear ratio of the reverse gear, Friction resistance is very small, and there is no risk of power loss.

It is needless to say that the present invention is not limited to the above-mentioned embodiment, and various changes can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the friction member is constituted by a C-shaped ring having a circular cross section so that the synchronizer key can overcome the tension of the friction member and overcome the tension, but the shape is not limited to this. A tapered surface may be provided on the outer peripheral portion of the, or a chamfer may be provided on the inner surface of the synchronizer key. Further, the friction member itself does not have to have a spring force, and the pin-shaped friction member may be biased in the protruding direction by a separate spring. Correspondingly, the part where the friction member is buried is not limited to the circumferential groove. Further, in the above embodiment, the inner surface of the synchronizer key is provided with a recess, and the friction member is fitted into this recess when shifting in the backward direction. However, the inner surface of the synchronizer key may be flat. However, the provision of the concave portion reduces the friction between the friction member and the synchronizer key in the state where the shift is completed to the reverse gear, and more desirable characteristics can be obtained. Further, in the above embodiment, the inertia lock type key type synchronizer has been described as an example, but the present invention is not limited to this, and the present invention can be similarly applied to a synchronizer not having a synchronizer key. The forward gear is not limited to the third speed gear, and any forward gear may be used. In particular, in the present invention, since there is almost no problem of power loss due to the difference in gear ratio between the forward gear and the reverse gear, there is an advantage that any forward gear can be selected.

[0015]

[Effect of device]

 As is clear from the above description, according to the present invention, the end of the sleeve or the member that rotates integrally with the sleeve pushes the friction member to the forward gear in the initial stage of the shift to the reverse gear, so A frictional force is generated between the friction member and the forward gear to brake the shaft that rotates integrally with the sleeve. Therefore, the reverse gear can be engaged while the shaft is stopped, and gear noise can be prevented. Further shifting in the backward direction causes the friction member to be buried in the sleeve-side end portion of the forward gear, and the frictional force between the sleeve and the friction member or between the friction member and the forward gear is almost eliminated. At the beginning of meshing of the reverse gear, the braking force on the shaft that rotates integrally with the sleeve is released, and the performance of entering the reverse gear can be improved. Even at the shift end point, there is almost no frictional force between the sleeve and the friction member or between the friction member and the forward gear, so the braking force during reverse travel is significantly smaller than before. Therefore, there is a characteristic that the power loss when traveling backward is very small.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a stroke and a shift load during a reverse shift.

FIG. 2 is a partial cross-sectional view of a manual transmission including a reverse gear squeal preventing device according to the present invention.

3A is a partially enlarged view of FIG. 2 before a reverse shift, and FIG. 3B is a partially enlarged view of FIG. 2 after a reverse shift.

FIG. 4 is a shift pattern diagram of a manual transmission according to the present invention.

[Explanation of symbols]

 1 Input Shaft 3 Third Speed Gear 3a Boss (End on Sleeve Side) 3b Circumferential Groove 8 Sleeve 11 Synchronizer Key 12 Friction Member

Claims (1)

[Scope of utility model registration request] 1. A sleeve that moves in the axial direction when shifting to a reverse stage, a forward gear that is adjacent to the moving direction side of the sleeve, and a sleeve that can extend and retract on the outer peripheral surface of the sleeve-side end portion of the forward gear. When the sleeve is moved in the axial direction, the sleeve or a member that rotates integrally with the sleeve presses the side surface of the friction member protruding from the sleeve side end portion, and the sleeve and the friction member are attached. A reverse gear squeal of a manual transmission characterized in that a frictional force is generated between the forward gear and the friction member is embedded in the sleeve side end portion by further movement of the sleeve. Prevention device.