JPS6143584B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gear noise prevention device for a multi-speed transmission equipped with a main transmission and an auxiliary transmission for switching between high and low speeds.

[Prior Art] This type of multi-speed transmission device has a main transmission that is manually switched, a sub-transmission that switches a fluid pressure circuit using a switch provided at the hand of a gear lever,
A hydraulic actuator switches the gears. The shift rod of the auxiliary transmission is provided with recesses corresponding to the high speed and low speed shift positions, and balls protruding from the casing engage with the recesses to firmly hold the gear in that position. ing.

Therefore, in the case of a switching operation, the hydraulic actuator cannot operate until a certain pressure is reached such that the ball disengages from the recess;
When pressure overcomes the engagement force, the shift rod is rapidly actuated by the hydraulic actuator. Since the resistance force during operation of the shift rod is not very large, the spline of the synchronized mesh clutch suddenly hits the dog teeth, which not only prevents smooth meshing but also causes gear noise.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention provides a gear noise prevention device for a multi-speed transmission in which a synchronized mesh clutch of an auxiliary transmission is operated smoothly to prevent gear noise. The purpose is to obtain.

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention maintains the operating position of the shift rod of a sub-transmission in a multi-speed transmission in which the shift rod of the sub-transmission is operated by a hydraulic actuator. The fluid pressure applied to the fluid pressure actuator is guided to the holding mechanism for releasing the holding force of the holding mechanism.

[Operation] When switching the sub-transmission, the engagement force between the recess and the ball that holds the shift rod is released in advance, and then the shift rod is operated by the fluid pressure actuator, so that the shift rod is transferred to the synchronized mesh clutch. The transmitted shock is alleviated.

[Embodiments of the Invention] The present invention will be described based on an embodiment. FIG. 1 is a longitudinal sectional view showing a sub-transmission portion of a multi-stage transmission. That is, the main transmission is disposed on the left side of the figure, and the end of its main shaft 4 is supported by a bearing 20 on the cylindrical portion of the output shaft 14 of the sub-transmission.

This output shaft 14 has a bearing 12 in a casing 16,
15, and its right end is rotationally connected to a propulsion shaft (not shown) via a universal joint. Gears 3 and 1 are provided in the casing 16 in parallel with the output shaft 14.
A shaft 21 that fixedly supports 7 is supported by a pair of bearings 18 . The gear 3 is meshed with a high speed gear 5 disposed on the main shaft 4 of the main transmission, and the gear 17 is meshed with a paper speed gear 19 supported on the output shaft 14 so as to be freely rotatable.

A synchronized meshing clutch 2 is constructed at the left end of the output shaft 14, thereby connecting the high speed gear 5 and the output shaft 14.
or the output shaft 14 and the low speed gear 19 are rotationally coupled. The synchronized mesh clutch 2 is operated by a shift lever 6 fixed to a shift rod 9.
is adapted to be actuated by a hydraulic actuator 10.

As shown in FIG. 2, the synchronizing clutch 2 has a synchronizing sleeve 41 provided with a spline 48 that is engaged with the left end of the output shaft 14.
is a dog tooth 4 formed integrally with the gears 5, 19.
9 or 49a. The synchronizing sleeve 41 is provided with a plurality of cylindrical portions 46 at intervals in the circumferential direction on the outer circumferential side, and a protruding piece 4 that is biased radially outwardly by a spring 47.
5 is accommodated. This protruding piece 45 is the synchronizing pin 5
0 recess 44.
The synchronization pin 50 supports synchronization rings 42, 42 each having a conical surface on the outer periphery.
2 and 42 are adapted to be engaged with conical cavities formed integrally with the aforementioned gears 5 and 19.
A hole 41a provided in the synchronization sleeve 41 is slidably fitted into the synchronization pin 50, and a bifurcated shift lever 6 attached to the shift rod 9 is fitted into an annular groove 41b formed on the outer periphery of the synchronization sleeve 41. fork is engaged.

The fluid pressure actuator 10 has a piston 38 fitted inside a cylinder 37 to define both end chambers 39 and 40, and a piston rod connected to the piston 38 integrated with the shift rod 9. Both end chambers 39 and 40 are conduits 35 and 3
6 to both end chambers of the switching valve 34. The switching valve 34 has a valve body 33 housed inside the housing 32, and when one of the electromagnetic three-way valves 29 and 30 is excited, fluid pressure is applied from the fluid pressure source 31 to one of the end chambers 32a and 32b. It's becoming like that.

One end of a conduit 28 communicating with the inside of the housing 32 is connected to the central portion of the switching valve 34, and the other end is connected to one chamber 27a of the cylinder 27. and,
A piston 24 is fitted inside the cylinder 27, and a spring 25 is interposed between the piston 24 and a cover plate 26 that closes the other end of the cylinder 27, thereby biasing the piston rod 23 against the ball 22. Match. The ball 22 is configured to selectively engage one of a pair of recesses 7 provided on the outer peripheral surface of the shift rod 9. The distance between the pair of recesses 7 is set to the stroke required to switch and operate the synchronized mesh clutch 2.

By configuring the present invention as described above,
When the electromagnetic three-way valve 29 is energized by the switch disposed near the gear shift lever in the state shown in FIG.
Fluid pressure is applied to the valve body 33, and the valve body 33 moves to the right. Therefore, the fluid pressure of the switching valve 34 enters the chamber 27a of the cylinder 27 via the conduit 28, pushes the piston 24 up against the spring 25, and releases the biasing force of the spring 25 acting on the ball 22. In addition, the switching valve 3
The fluid pressure in the left end chamber 32b of the hydraulic actuator 10 enters the left end chamber 39 of the hydraulic actuator 10 through the conduit 35 and moves the piston 38 to the right. At this time, since the biasing force of the spring 25 is not acting on the ball 22, the ball 22 can be easily moved upward by sliding of the shift rod 9, and the shift rod 9 moves smoothly as the pressure in the end chamber 39 increases. .

As in the conventional case, the shift rod 9 is stopped until the pressure in the end chamber 39 rises above a certain level, and when the engagement force between the ball 22 and the recess 7 is released against the force of the spring 25, the shift rod 9 suddenly moves. shift rod 9
When the synchronizing sleeve 41 engaged with the shift lever 6 attached to the shift lever 6 moves to the right along the synchronizing pin 50 even in the illustrated state, the protruding piece 45 moves without engaging the recess 44, so that the synchronizing Spline 48 engages dog teeth 50 without action, resulting in gear noise.

However, according to the present invention, since the shift rod 9 smoothly moves to the right as the pressure in the end chamber 39 of the fluid actuator 10 increases, the protrusion 45
engages the recess 44 and pushes the synchronizing pin 50 to the right, so the synchronizing ring 42 simultaneously moves to the right,
A synchronizing action is performed by frictionally engaging the conical portion of the gear 19. Therefore, when the rotation of the gear 19 is synchronized, the protruding piece 45 overcomes the recess 44 and the synchronizing sleeve 41 moves to the right, so that the spline 48 of the synchronizing sleeve 41 smoothly engages with the dog tooth 50. I can do it.

The switching valve 34 has a smaller volume and operating resistance than the fluid pressure actuator 10, and the volume of the housing 32 is also smaller, so it operates instantly when the electromagnetic three-way valve 29 is energized. The shift rod 9 can be operated smoothly without being subjected to resistance from the ball 22.

When the gear shifting operation is completed as described above, the power to the electromagnetic three-way valve 29 is cut off by a release switch (not shown) which is activated by movement of the shift rod 9, as in the conventional case. For,
The electromagnetic three-way valve 29 is demagnetized, both end chambers of the switching valve 34 are opened to the atmosphere, and the end chamber 27a of the cylinder 27 is also at atmospheric pressure, so the spring 25
The rod 23 is biased by the lock 23, and the ball 22 is engaged in the recess 7 to maintain the engaged position of the synchromesh clutch.

Similarly, when the electromagnetic three-way valve 30 is energized, contrary to the above, fluid pressure is first applied to the end chamber 27a of the cylinder 27 via the conduit 28, the ball engagement force of the rod 23 is released, and the synchronized mesh clutch 2 can be switched smoothly.

[Effects of the Invention] Since the present invention is configured as described above, the spring force that normally engages the ball 22 with the recess 7 of the shift rod 9 is applied to the pressure of the fluid pressure source 31 at the same time as the sub-transmission is operated. Shift Rod 9
The synchronization ring 4 operates smoothly and not abruptly.
1, the protruding piece 45 engages with the recess 44 and pushes the synchronizing rings 42, 42 toward the gear 19 or 5 to be shifted, and after the rotation of the shifting gear and the rotation of the synchronizing sleeve 41 are synchronized, the synchronization occurs. ring 4
1 spline 48 and dog tooth 49a or 4
9, it is possible to prevent the gear noise caused by the sudden and unreasonable meshing of the spline 48 and the dog teeth 49 as in the conventional example, and has the excellent effect of improving the durability life of the synchronized mesh clutch. is obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a sub-transmission section of a conventional general multi-stage transmission, and FIG. 2 is a longitudinal sectional view of a gear noise prevention device for a multi-stage transmission according to the present invention. 2: Synchronous mesh clutch, 4: Main shaft, 6: Shift lever, 7: Recess, 9: Shift rod, 10:
Fluid pressure actuator, 14: Output shaft, 16: Casing, 22: Ball, 23: Rod, 24:
Piston, 25: Spring, 27: Cylinder, 28:
Conduit, 29, 30: Electromagnetic three-way valve, 31: Fluid pressure source, 34: Switching valve, 38: Piston.

Claims (1)

[Claims] 1. In a multi-stage transmission in which the shift rod of the auxiliary transmission is operated by a fluid pressure actuator,
Gear noise of a multi-stage transmission, characterized in that the structure is configured such that fluid pressure applied to the fluid pressure actuator is guided to a holding mechanism for holding the operating position of the shift rod, and the holding force of the holding mechanism can be released. Prevention device.