JPS6346756Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid pressure actuator for shifting operations in a multi-stage transmission device that includes a main transmission and an auxiliary transmission for switching between high and low speeds.

In this type of multi-speed transmission, the main transmission is operated by a manual shift lever, the auxiliary transmission is connected to a fluid pressure actuator, and the fluid pressure circuit of this fluid pressure actuator is installed near the shift lever. It is designed to be operated by a switch.

In a split-type multi-speed transmission, in the case of a shift-up operation, the first gear of the main transmission shifts the sub-transmission from a low gear to a high gear, and the second gear of the main gear shifts the sub-transmission from a low gear to a high gear. It is now possible to operate in sequence. However, in a conventional fluid pressure actuator using a cantilevered piston, the following problems occur because the areas receiving fluid pressure in the forward and backward directions of the piston are different.

In other words, in the case of a shift-up operation, the auxiliary transmission is operated alternately from a low gear to a high gear, and from a high gear to a low gear, but for an operation from a low gear to a high gear, the pressure received by the piston is Since the area is large, the shift operation of the auxiliary transmission can be performed quickly, but on the other hand, since the pressure receiving area of the piston is small, the shift operation of the auxiliary transmission becomes slow when shifting from a high gear to a low gear. This impedes the acceleration of the vehicle through smooth gear shifting operations.

Of course, it is possible to increase the operation speed from the high speed gear to the low gear by increasing the fluid pressure of the fluid pressure actuator, but in this case, the operation speed from the low gear to the high gear will become too fast. The dog teeth in the synchronized meshing clutch mechanism may hit hard and cause damage.

Although it is conceivable to use a reciprocating type fluid pressure actuator as the fluid pressure actuator, in reality, as shown in FIG. The cover 27 of the main transmission case 24 is located in the front part, and the lever 33 of the center drum brake and other upwardly protruding members are located in the rear part, so the cylinder 32
The reason is that it is not possible to make it longer.

In view of the above-mentioned problems, the purpose of the present invention is to make the operating force from the high gear to the low gear of the auxiliary transmission equal to the operating force from the low gear to the high gear, without changing the conventional shape and dimensions. It is an object of the present invention to provide a fluid pressure actuator for speed change operation that can be operated quickly.

For this reason, the configuration of the present invention connects one end of a shift rod that supports a shift lever to a piston of a fluid pressure actuator, and closes the end of a case that supports the other end of the shift rod to form a reaction force chamber. , the reaction force chamber and the end chamber of the fluid pressure actuator are connected by a passage passing through the shift rod.

The present invention will be explained based on examples. FIG. 1 is a longitudinal sectional view showing a sub-transmission portion of the multi-stage transmission. That is, the main transmission is arranged on the left side of the figure, the main shaft 4 is supported by a bearing 25 on the end wall of the case 24, and the first speed gear 48 and the second speed gear 47 can freely rotate on this. It is supported and rotatably coupled to the main shaft 4 by a synchronized meshing clutch mechanism 49 disposed therebetween.

A bifurcated shift lever 26 is engaged with the synchronized mesh clutch mechanism 49, and this shift lever 26 is supported by a shift rod 28 that is slidably supported in the front and rear directions by a cover 27 that closes the upper end of the case 24. When the shift rod 28 is slid in the axial direction by a known speed change lever, the first speed gear 48 or the second speed gear 47 is selectively coupled to the main shaft 4 for rotation.

An end portion of the main shaft 4 projects into the interior of the case 16 of the sub-transmission, and the end portion is supported by a bearing 20 on the cylindrical portion of the output shaft 14 of the sub-transmission. This output shaft 1
4 is supported by the case 16 of the sub-transmission with bearings 12 and 15, and its right end is rotationally coupled to a propulsion shaft (not shown) via a flange joint 37 and a universal joint 35. In the case 16, a shaft 21 supporting the gears 3, 3a parallel to the output shaft 14 has bearings 22,
18. The gear 3 is meshed with a high-speed gear 5 spline-coupled to the main shaft 4 of the main transmission, and the gear 3a is meshed with a low-speed gear 19 rotatably supported on the output shaft 14.

A synchronized meshing clutch mechanism 2 is constructed between the gear 5 and the gear 9, whereby the high speed gear 5 and the output shaft 14 are rotationally coupled, or the low speed gear 19 and the output shaft 14 are rotationally coupled. They are becoming connected. The synchronized mesh clutch mechanism 2 is operated by a shift lever 6 fixed to a shift rod 9.
The shift rod 9 is supported by a cover 30 that closes the upper end of the case 16, and is actuated by a hydraulic actuator 10.

According to the present invention, as shown in FIG. 2, the fluid pressure actuator 10 has a cylinder 32 coupled to the end of a cover 30, and a piston 31 fitted inside the cylinder 32 to define end chambers 43 and 44. , a shift rod 9 is connected to a piston 31.
A sealing member 45 is attached to the cylindrical portion of the cover 30 that guides the shift rod 9. shift rod 9
A sealing member 46 is attached to the cylindrical portion 29 that guides and supports the left end of the cylinder 32 , and a reaction force chamber 39 is formed by screwing the plug 38 together. A connecting passage 50 is provided through the shift rod 9.

In addition, in order to hold the shift rod 9 in the low gear and high gear positions, the shift rod 9 has a recess 7.
is provided with a ball 10 by a spring 41.
is adapted to be forcefully engaged. Furthermore, a pair of switches 42 are disposed on the cover 30 and are actuated by a cam 51 provided at the base end of the shift lever 6 to control the fluid pressure circuit after the shift operation is completed. , since this is not directly related to the gist of the present invention, it will not be further explained.

Further, as shown in FIG. 1, the back plate 36 of the brake drum is fixedly supported at the end of the case 16, while the end wall of the brake drum 34 is held between the flange joint 37 and the universal joint 35. be done. A pair of brake shoes disposed on the back plate 36 rotate the cam 52 supported on the back plate 36 by the brake lever 33 and press it against the inner peripheral surface of the brake drum 34 to apply braking force during parking. I'm starting to get it.

Next, the operation of the device of the present invention will be explained. As shown in FIG. 2, when the auxiliary transmission is set to high speed, when pressure fluid is supplied to the end chamber 44, the piston 31 moves to the left end wall of the cylinder 32, actually to the cover 3.
0, the synchronized meshing clutch mechanism 2 shown in FIG. 14.

On the other hand, when the sub-transmission is set to a low gear, the end chamber 43
When pressure fluid is supplied to the piston 31, the shift rod 9 moves to the right, the synchronized mesh clutch mechanism 2 is pushed to the right by the shift lever 6, and the rotational connection between the output shaft 14 and the gear 19 is established. can be achieved. Therefore, the rotation of the main shaft 4 is caused by the gear 5,
The signal is transmitted to the output shaft 14 via the gear 3 and the gear 3a and gear 19 that are integrated therewith.

According to the present invention, when pressure fluid is supplied to the end chamber 44, a force that pushes the piston 31 to the right acts on the reaction force chamber 39 through the passage 5. Therefore, the fluid pressure that pushes the piston 31 to the left is the cross-sectional area of the piston 31 minus the cross-sectional area of the shift rod 9, and this pressure-receiving area is equal to the pressure-receiving area that the fluid pressure exerts on the piston 31 in the end chamber 43. Become. Therefore, the piston 31 in the end chamber 44
However, by increasing the fluid pressure applied to the fluid pressure actuator 10 by this amount, the shift operation speed from the high gear to the low gear and the shift operation speed from the low gear to the high gear can be made equal. can do.

As described above, the present invention is designed to eliminate the difference between the piston pressure receiving area on the high output side and the piston pressure receiving area on the small output side in conventional fluid pressure actuators.
Since the reaction force chamber 39 is provided at the opposite end, the fluid pressure acting on the piston 31 is equal in both directions of movement of the shift rod 9, and the shift from a low gear to a high gear in a shift-up operation of a multi-speed transmission. By making the operation time from the high speed gear to the low speed gear equal to the operation time from the high speed gear to the low gear, and by increasing the fluid pressure, the shift operation time is shortened, and a smooth upshift operation can be achieved.

Furthermore, since the conventional fluid pressure actuator is used as is, and only a reaction force chamber is provided at the end of the shift rod 9, which is connected to the large output side chamber of the fluid pressure actuator, the configuration is simple and can be used in a restricted occupied space. This makes it possible to install the multi-speed transmission, and provides the excellent effect of significantly improving the operability of the multi-stage transmission.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a sub-transmission portion including a fluid pressure actuator for shifting operation according to the present invention, and FIG. 2 is a side sectional view of the fluid pressure actuator for shifting operation. 6...Shift lever, 9...Shift rod, 1
0...Fluid pressure actuator, 16...Case,
30... Cover, 31... Piston, 32... Cylinder, 38... Plug, 39... Reaction force chamber, 49
...Synchronized mesh clutch mechanism.

Claims (1)

[Scope of utility model registration request] One end of a shift rod supporting a shift lever is coupled to a piston of a fluid pressure actuator, and an end of a case supporting the other end of the shift rod is closed to form a reaction force chamber, and the reaction force chamber and the fluid A fluid pressure actuator for speed change operation, characterized in that an end chamber of the pressure actuator is connected to the end chamber by a passage passing through the shift rod.