JP2001227642A - Power assist for operating transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent shift operation from becoming heavy again halfway and prevent the generation of stop sound at the end of shift operation in a transmis sion operating assistor provided with a piston fixed to the outer periphery of an output shaft, a working pressure supply path for leading working pressure into the pressure receiving face of the piston, a working pressure discharge path for opening the pressure receiving face of the piston to the atmosphere, and a valve means for opening/closing the working pressure supply path and the discharge path interlockingly with an input shaft. SOLUTION: The working pressure discharge paths 30, 37, and the like are provided with orifices 47, 54 downstream of the valve means 10, and working pressure retaining capacities 45, 58 are provided between the orifices 47, 54 and the valve means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster for operating a transmission.

[0002]

2. Description of the Related Art In a large vehicle such as a truck, a transmission operating booster is used to reduce the shift operation force of the transmission. FIG. 4 and FIG. 5 illustrate an example thereof.
Reference numeral 1 denotes a power cylinder in which a piston 3 is housed. The piston 3 is fixed to the outer periphery of the shifter rod 4 (output shaft), and when compressed air (operating pressure) is supplied to one of the two chambers A and B (the other is open to the atmosphere), the piston 3 is compressed by the compressed air. Output occurs.

[0003] This output is transmitted from the shifter rod 4 to the striker 5, and operates the shift fork of the transmission.
The striker 5 is fixed to the outer periphery of the shifter rod 4, and a detent mechanism (a steel ball that fits on a spherical surface on the rod side and a spring that urges the spherical surface on the spherical surface on the rod side) Is provided).

[0004] The actuating rod 6 is inserted into the shifter rod 4, and one end of a pipe 7 is connected to a distal end thereof by a connector 8. The other end of the pipe 7 is connected to a supply pipe for compressed air, and supplies compressed air through a hole 12 to a primary chamber 11 of a valve means 10 described later. When the end of the change lever is connected to the protruding end of the actuating rod 6 and receives a lever operation force (shift operation force) to cause relative displacement with the shifter rod 4 (the steel ball of the detent mechanism rides on the spherical surface), the piston 3 Output occurs.

[0005] The valve means 10 is assembled between the pipe 7 and the shifter rod 4. 1 on inner circumference of shifter rod 4
The pair of cylindrical bodies 13a and 13b are fixed. Cylindrical body 13
a, flanges 14a projecting radially to the inner circumference of 13b,
14b is formed, and a pair of valves 15a, 15b is housed between the flanges 14a, 14b. Valve 15
A and 15b are movably supported on the pipe 7, and a seat portion 16 is mounted on each back surface. A gap is set between the outer diameters of the valves 15a and 15b and the inner diameters of the cylindrical bodies 13a and 13b, and the valves 15a and 15b are arranged such that the seat portion 16 is in close contact with the flanges 14a and 14b of the cylindrical bodies 13a and 13b. A biasing spring 17 is interposed.

The flanges 14a of the cylindrical bodies 13a, 13b,
Valve lifters 20a and 20b are respectively disposed on opposite sides of the valves 15a and 15b with respect to the valve 14b. Each of the valve lifters 20a and 20b includes a large-diameter portion 21 (rear end portion) that is in sliding contact with the inner periphery of the shifter rod 4, and a small-diameter portion 22 (tip portion) that can pass through the inner diameter of the flanges 14a and 14b. A spring 23 is interposed between the rear end 21 and the flanges 14a and 14b, and the valve lifter 20a is locked to a ring 24 fixed to the pipe 7 by the urging force of the spring 23, while the valve lifter 20b is attached to the spring 23. The connector 8 is locked by the force.

When the valve lifters 20a and 20b move in the compression direction of the spring 23 with respect to the shifter rod 4,
The tip 22 connects the valves 15a, 15b to the flanges 14a,
Lift from 14b. Between the valves 15a and 15b (1
The compressed air in the secondary chamber 11) is guided to the secondary chamber 25 from the outer periphery and the rear surface of the valves 15a and 15b through the gap between the flanges 14a and 14b and the tip portions 22 of the valve lifters 20a and 20b. In order to further supply the compressed air to the chambers A and B inside the cylinder 1, an annular groove 26 is formed on the outer periphery of the cylindrical bodies 13 a and 13 b, and a hole 28 opening the annular groove 26 to the secondary chamber 25, Similarly, a hole 29 is formed in the annular groove 26 to open the chambers A and B inside the cylinder 1. Thus, the valves 15a, 15b and the flanges 14a, 1
The supply path is formed by the gap with the secondary chamber 4b, the secondary chamber 25, the hole 28, the annular groove 26, and the hole 29.

A clearance passage 30 is set in the inner diameter of the valve lifters 20a and 20b (between the outer diameter of the pipe 7). The gap passage 30 of the valve lifter 20b is opened from the inner diameter portion (gap passage) of the connector 8 and the mesh 35 to the atmosphere side via the inside of the actuating rod 6. The gap passage 30 of the valve lifter 20a is opened from the gap of the ring 24 to the atmosphere through the port 37 of the end plug 36 (to which the mesh 38 is attached). in this way,
Hole 29, annular groove 26, hole 28, secondary chamber 25, valve 1
Gaps between 5a, 15b and valve lifters 20a, 20b,
The exhaust passage is constituted by the gap passage 30, the port 37 or the internal hole of the operating rod 6.

With such a configuration, when the actuating rod 6 is operated in the shift direction with respect to the shifter rod 4, this movement is transmitted via the pipe 7 to the valve lifter 2.
0a and 20b. In FIG.
When the pipe 7 is displaced to the left, it is pushed by the connector 8 and the valve lifter 20b is displaced to the left (forward) while compressing the spring 23. Tip portion 22 of valve lifter 20b
Abuts on the seat portion 16 of the valve 15b, the gap passage 30 is shut off from the secondary chamber, and when it further advances, the seat portion 16 separates from the flange 14b. This gives 1
Compressed air flows from the secondary chamber 11 to the secondary chamber 25, and is further supplied to the chamber B on the right side of the cylinder 1 via the annular groove 26 of the cylindrical body 13b, thereby causing the piston 3 to generate an output in the shift direction. This output is transmitted from the shifter rod 4 to the striker 5, and operates the shift fork of the transmission.

When the input (shift operation force) to the actuating rod 6 is released, the pipe 7 is pushed back to the initial (neutral) position together with the valve lifter 20b due to the restoring force of the spring 23 and the like. In this process, when the valve 15b is seated on the flange 14b with the retreat of the valve lifter 20b, the gap between the valve 15b and the flange 14b is sealed by the seat portion 16, so that the communication between the primary chamber 11 and the secondary chamber 25 (to the cylinder 1). Supply of compressed air) is shut off,
At about the same time, when the distal end portion 22 of the valve lifter 20b separates from the seat portion 16 of the valve 15b, the gap passage 30 communicates with the secondary chamber 25, and the compressed air on the cylinder 1 side is discharged to the actuating rod 6 side. . In addition,
When the actuating rod 6 is shifted in the opposite direction, the movement is transmitted to the opposite valve lifter 20a through the pipe 7, and compressed air is supplied to the left chamber A of the cylinder 1 by the same action. , Causing the piston 3 to generate an output in the opposite direction. Also, when the distal end portion 22 of the valve lifter 20a moves away from the seat portion 16 of the valve 15a, the compressed air on the cylinder 1 side flows from the gap passage 30 to the port 3
It is discharged to the 7 side.

[0011]

FIG. 3 shows a change in load (shift operation force) according to a shift operation stroke in such a conventional apparatus. At the beginning of the shift, the shift shaft locking mechanism of the transmission and the synchronizing mechanism of the transmission cause resistance, so a relatively large shift operation force is required, and an output (power assist) corresponding to this operation force is generated on the piston 3. I do. After that, when the synchronizing action is completed, the resistance drops sharply, so that the shift operation force decreases and the relative position between the shifter rod 4 and the actuating rod 6 returns to neutral, and the power assist sharply decreases. I do. In this state, if resistance occurs in the shift operation, such as when the sleeve collides with the clutch gear of the transmission, the resistance is not so large as to cause relative displacement between the shifter rod 4 and the actuating rod 6, so that power assist does not occur. Therefore, a considerable shift operation force is required. For this reason, the driver feels that the shift operation becomes heavy again near the center of the stroke of the shift operation, and there is a problem that the feeling of the shift operation is not good.

An object of the present invention is to provide a countermeasure for remedying such a problem.

[0013]

According to a first aspect of the present invention, there is provided a piston fixed to an outer periphery of an output shaft, a supply path of a working pressure introduced to a pressure receiving surface of the piston, and a working pressure for releasing the pressure receiving surface of the piston to the atmosphere. And a valve means for opening and closing the supply path and the discharge path of the working pressure in conjunction with the input shaft, the booster for operating a transmission, the discharge path of the working pressure being downstream of the valve means. An orifice is provided.

In the second aspect of the present invention, a reserve volume of the operating pressure is provided between the orifice and the valve means in the operating pressure discharge path according to the first aspect of the invention.

[0015]

According to the first aspect of the invention, when the supply path of the working pressure is opened and the discharge path is closed, the working pressure is supplied to the pressure receiving surface of the piston, and an output (power assist) is generated at the piston. When the supply path of the operating pressure is closed and the discharge path is opened, the pressure receiving surface of the piston is opened to the atmosphere, but the orifice gradually reduces the operating pressure. When the operating pressure (power assist) is still sufficiently remaining on the pressure receiving surface of the piston, the resistance that acts near the center of the stroke of the shift operation is met so that the shift operation becomes heavier in the middle. Can be prevented.

In the second aspect of the present invention, the orifice reduces the operating pressure moderately, but if the operating pressure remains when the gears of the transmission are completely engaged, the impact of the power assist causes a large impact sound ( Stop sound) may occur, but by providing a holding volume for the working pressure, the working pressure drops quickly until the holding volume is filled, and then the orifice works.
The stop sound can be prevented from being generated while the shift operation is prevented from becoming heavy again.

[0017]

In FIG. 1, a supply pipe for compressed air is connected to one end of a pipe 7 for supplying an operating pressure to a piston 3. This compressed air is supplied to the primary chamber 11 through the hole 12 of the pipe 7 as before,
The valve lifters 20a, 20b are attached to the seat portions 16a, 15b.
b abuts and the sheet portion 16 separates from the flanges 14a and 14b, flows into the secondary side chamber 25, and the hole 28 and the annular groove 26
And the holes 29 are supplied to the chambers A and B inside the cylinder 1. The valve lifters 20a, 20b are separated from the seat portions 16 of the valves 15, 15b, and the seat portions 16 are
a, 14b, the primary chamber 11 and the secondary chamber 25
Is cut off, the gap passage 30 between the valve lifters 20a and 20b is opened, and the operating pressure inside the cylinder 1 is discharged to the atmosphere via an exhaust path described later. The same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals, and redundant description will be avoided.

A cylindrical guide 40 for guiding sliding of the valve lifter 20a is provided between the cylindrical body 13a and the end plug 36 of the shifter rod 4, and a rear end of the valve lifter 20a is connected to a pipe via a spacer 41 and a ring 24. 7 locked on the outer periphery. At a neutral position of the pipe 7, a predetermined gap 45 is set between the spacer 41 including the ring 24 and the end plug 36, and relays the port 37 on the end plug 36 side and the gap passage 30 on the valve lifter 20a side. An orifice 47 is formed in the port 37 of the end plug 36 to form an opening on the side of the gap 45.

When the valve lifter 20a separates from the seat 16 of the valve 15a and the seat 16 comes into contact with the flange 14a and the gap passage 30 of the valve lifter 20a is opened, the compressed air in the chamber A inside the cylinder 1 is released. From the gap passage 30 through the gap between the spacer 41 and the ring 24 into the gap 45, and when the gap 45 has substantially the same pressure as the chamber A inside the cylinder 1, the gas is discharged from the port 37 through the orifice 47 to the atmosphere. .

A cylindrical guide 51 with a bottom is provided between the cylindrical body 13b and the step 50 formed on the inner periphery of the shifter rod 4 to guide the sliding of the valve lifter 20b. A shaft hole 52 is opened at the bottom of the guide 51, and a small diameter portion 53 to be inserted into the shaft hole 52 is formed at the tip of the actuating rod 6, and these (the inner periphery of the shaft hole 52 and the outer periphery of the small diameter portion 53) are formed. An orifice 54 is set between them. The rear end of the valve lifter 20b is locked to the distal end of the small-diameter portion 53 via a spacer 56. At a neutral position of the pipe 7, a gap 58 is set between the spacer 56 and the bottom surface of the guide 51, and a gap passage on the valve lifter 20b side 30 and the orifice 54 are relayed.

When the valve lifter 20b separates from the seat 16 of the valve 15b and the seat 16 comes into contact with the flange 14b and the gap passage 30 of the valve lifter 20b is opened, the compressed air in the chamber B inside the cylinder 1 is released. When the space 58 has substantially the same pressure as the chamber B inside the cylinder 1, the space 58 is discharged to the atmosphere side from the space inside the shift rod 4 through the orifice 54. You.

With such a configuration, when the synchronizing operation of the transmission is completed in the course of the shift operation, the resistance sharply drops, so that the shift operation force decreases and the shift rod 4 and the actuating rod 6 The relative position returns to neutral. Therefore, the valves 15a, 1
When the valve lifters 20a and 20b are separated from the seat 16 of the valve lifter 5b and the seats 16 come into contact with the flanges 14a and 14b and the gap passage 30 of the valve lifters 20a and 20b is opened, the compressed air in the chambers A and B inside the cylinder 1 is opened. Is discharged to the atmosphere through a discharge path passing through the predetermined gaps 45 and 58 (reserved volumes) and the orifices 47 and 54 as described above, and is power assisted (output generated in the piston).
Decreases rapidly.

At this time, the working pressures of the chambers A and B rapidly decrease until the gaps 45 and 58 (reserved volumes) are filled, as shown by the dotted lines in FIG.
, So it gradually decreases. Therefore, the piston 3
In the state where the operating pressure (power assist) still remains sufficiently on the pressure receiving surface, the resistance that acts near the center of the stroke of the shift operation is received, thereby preventing the shift operation from becoming heavy during the shift operation ( Also, generation of a stop sound at the end of the shift operation can be prevented.

When only the orifices 47 and 54 are used (the predetermined gaps 45 and 58 are not set), it is difficult to secure the remaining pressure in the chamber enough to prevent the shift operation from becoming heavy again. At the end of the operation, unnecessary operating pressure remains, and a stop sound is likely to be generated in the transmission due to the momentum of the power assist. However, if attention is paid to preventing the shift operation from becoming heavy again on the way, it is not necessary to set the gaps 45 and 58 (reserved volumes), and only the orifices 47 and 54 may be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a cross section of a main part showing an embodiment of the present invention.

FIG. 2 is an output (power assist) characteristic diagram.

FIG. 3 is an input (shift operation force) characteristic diagram.

FIG. 4 is a partial cross-sectional configuration diagram illustrating a conventional device.

FIG. 5 is a configuration diagram of a cross section of the main part.

[Explanation of symbols]

 Reference Signs List 1 power cylinder 3 piston 4 shifter rod (output shaft) 5 striker 6 actuating rod (input shaft) 7 pipe 10 valve means 11 primary side chambers 14a, 14b flange 15a, 15b valve 16 seat portion 20a, 20b valve lifter 30 gap passage 45, 58 void (reserved volume) 47,54 orifice

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Abe 2-1-6 Shinmeicho, Higashimatsuyama-shi, Saitama Prefecture Inside the Boss Brake System Co., Ltd. (72) Inventor Akira Shibasaki 2-1 Shinmeicho, Higashimatsuyama-shi, Saitama Prefecture 6 F-term in Bosch Brake System Co., Ltd. (reference) 3J067 AB13 AC02 DB23 DB25 GA04

Claims (2)

[Claims] 1. A piston fixed to the outer periphery of an output shaft, a supply path of operating pressure introduced to a pressure receiving surface of the piston, a discharge path of operating pressure for releasing the pressure receiving surface of the piston to the atmosphere, and a supply path of operating pressure. And a valve means for opening and closing the discharge path in conjunction with the input shaft, wherein an orifice is provided downstream of the valve means in the discharge path of the operating pressure. Booster for machine operation. 2. The booster for operating a transmission according to claim 1, wherein a reserve volume of the operating pressure is provided between the orifice and the valve means in the operating pressure discharge path.