JPH072669U - Booster for transmission operation - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent residual pressure when returning to neutral and improve operability. [Structure] Two cup packings 30 on the piston 2a,
31 with the lip portions 30a, 31a thereof facing each other, and at the inner peripheral surface of the cylinder body 4, the recess 32 is completely formed between the cup packings 30, 31 when the piston 2a is in the neutral position. When the piston 2a is formed over the circumference and returns to the neutral position, the lip portions 30a, 31a of the cup packings 30, 31 on the front side with respect to the traveling direction of the piston 2a are fitted in the recess 32. The lip portions 30a, 31a of the cup packing 31 on the rear side are pushed down by the compressed air so as to be separated from the inner peripheral surface of the cylinder body 4 while being separated from the bottom surface, or by the inner peripheral surface of the cylinder body 4. A recess 36 is formed over the entire circumference at a position where the packing of the piston 2a is to be slidably contacted at the neutral position. Causing a gap between the bottom surface 36a and the packing.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a booster device for operating a transmission, which boosts an operating force by a fluid pressure such as compressed air when operating a transmission such as an automobile.

[0002]

[Prior art]

 The operation of the transmission generally requires a larger force for the shift operation than the select operation. For this reason, especially in buses and trucks with large transmissions, a booster is attached to the transmissions, enabling smooth shift operations with a light force.

As a booster of this type, one shown in FIG. 11 is known (see Japanese Patent Application No. 1-101514). This device moves the operating rod b in the axial direction by operating the change lever a, thereby actuating the switching valve A to supply compressed air to one of the pressure chambers C ₁ and C ₂ and the piston rod d. It is configured to follow the movement of the operating rod b and obtain a boosted operating force from the striker e of the rod d. In addition, the operating rod b is linked to the piston rod d via the detent mechanism f to position them.

By the way, since this device is provided with the detinting mechanism f, the piston rod d accurately follows the operating rod b, and the switching valve A is in a neutral state (valve lifter) at any of the shift and neutral positions. g and the floating valve h can be maintained symmetrically). However, the installation of the detinting mechanism f not only causes an increase in weight and cost, but also has a drawback that the shift operation becomes heavy. For this reason, recent devices tend to omit this detinting mechanism f.

[0005]

However, if the detinting mechanism f is omitted, the following problems will occur. That is, the change lever a has some play in the shift direction at the neutral position. Now, when the change lever a is moved by this amount of play, the neutral state of the switching valve A collapses, the tip of the valve lifter g is pressed against the floating valve h as shown in FIG. 12, and the exhaust passage g ₁ of the valve lifter g is closed. It will be blocked (the figure shows the case where the operating rod is moved in the direction of the arrow). By the way, when the change lever a is returned to the neutral position, if such an operation is performed before the compressed air in the pressure chambers c ₁ and c ₂ is completely discharged, one of the pressure chambers c ₁ and c ₂ is left behind. Pressure is generated. At this time, a residual thrust is generated on the piston rod d, so that the shift lever of the transmission device is pressed against the shift jaw of the transmission. FIG. 13 is a view conceptually showing this state. The shift jaw J is normally in the neutral position shown by the chain double-dashed line, but when residual pressure occurs, it is in a state of being pressed against the shift lever L. If the select operation is performed in such a state, the change lever a will be caught.

In view of such circumstances, an object of the present invention is to provide a booster device for operating a transmission, which prevents residual pressure from occurring and improves operability.

[0007]

[Means for Solving the Problems]

 The present invention for solving the above-mentioned problems includes a cylinder body, a hollow piston rod slidably arranged in the cylinder body, an operation rod inserted in the piston rod, and a piston of the piston rod. A switching valve disposed in the piston rod for selectively supplying compressed air to one of two pressure chambers defined in the cylinder body, and the operation rod in the piston rod in the axial direction. To operate the switching valve, supply compressed air to one of the pressure chambers to operate the piston rod, and cause the piston rod to follow the movement of the operation rod. In the force device, the two cup packings are attached to the piston with their lip parts facing each other, and the inner peripheral surface of the cylinder body is mounted. When the piston is in the neutral position, a recess is formed over the entire circumference between the cup packings, and when the piston returns to the neutral position, the front side in the traveling direction of the piston is described. Either the lip of the cup packing fits into the recess and separates from the bottom surface, and the lip of the cup packing on the rear side is pushed down by compressed air to separate from the inner peripheral surface of the cylinder body. On the inner peripheral surface of the cylinder body, a recess is formed over the entire circumference at a position where the packing of the piston should be in sliding contact with the neutral position, and a gap is created between the bottom surface of the recess and the packing. Is characterized by.

[0008]

[Action]

 In the device according to claim 1, when the piston returns to the neutral position, the compressed air in the pressure chamber leaks into the space between the front and rear cup packings through the cup packing on the rear side with respect to the piston advancing direction, and the front side. The lip part of the cup packing of is pressed against the inner surface of the cylinder body. In other words, the piston is sealed only by the front cup packing. Then, when the front cup packing reaches the recess, the lip portion fits into the recess and separates from the bottom surface. Then, the lip portion of the rear cup packing is pushed down by the compressed air, and the compressed air flows into the front pressure chamber through the recess. In the device of the second aspect, when the piston returns to the neutral position, the compressed air flows into the pressure chamber on the opposite side through the gap between the packing and the bottom surface of the recess.

[0009]

【Example】

 FIG. 1 shows a booster for operating a transmission according to the present invention. In this booster, the operating rod 1 as an input shaft is connected to a change lever via a predetermined link mechanism (not shown), and a striker 3 is attached to the outer circumference of a piston rod 2 as an output shaft. The striker 3 is connected to a shift lever of a transmission device (not shown). Then, the shift lever of the transmission device is rotated by the reciprocating movement of the piston rod 2, and the shift operation of the transmission is performed.

More specifically, the booster includes a hollow piston rod 2 slidably arranged in a cylinder body 4, and an operation rod 1 inserted from one end of the piston rod 2 into the inside thereof. A switching valve 5 is installed inside the piston rod 2 at a position deeper than the tip of the operating rod 1. This switching valve 5 urges a pair of floating valves 6, 7 in a direction in which they are separated from each other by a compression spring 8 and presses them against fixed valve seats 9, 10, and at the same time, a valve lifter is provided outside these floating valves 6, 7. 11 and 12 are arranged, and the compression springs 13 and 14 are configured to urge them in opposite directions.

On the other hand, an air pipe 16 having a passage 15 for compressed air is arranged inside the piston rod 2 on the side opposite to the operation rod 1. One end of the air pipe 16 is an end portion of the operation rod 1. , And the other end side is communicated with the compressed air supply port 17. A port 18 is formed in the air pipe 16 in the radial direction, and the passage 15 communicates with the hollow chamber 19 formed in the piston rod 2 through the port 18. Then, compressed air is supplied to the hollow chamber 19 through the air pipe 16. Reference numerals 20 and 21 are slits formed on the end surfaces of the valve lifters 11 and 12.

As shown in FIG. 4, two cup packings 30 and 31 are mounted on the piston 2a with their lip portions 30a and 31a opposed to each other. On the other hand, on the inner peripheral surface of the cylinder body 4, a recess 32 is formed over the entire circumference between the cup packings 30 and 31 when the piston 2a is in the neutral position. The concave portion 32 has a trapezoidal cross section, and the lip portions 30a and 31a of the cup packings 30 and 31 are in sliding contact with the opening edges thereof (see FIG. 4).

The piston rod 2 is connected to the operation rod 1 using a pin 33 that fixes the striker 3. Specifically, as shown in FIG. 3, a pin 33 is fitted into the striker 3 and the piston rod 2, and the pin 33 is engaged with the elongated hole 1a of the operating rod 1. As a result, the relative rotation of the operating rod 1 and the piston rod 2 is prevented, and the valve opening amount of the switching valve 5 is fixed.

Now, when the operation rod 1 is moved to the right in the drawing by a change lever (not shown), the operation rod 1 pulls the air pipe 16 and moves the valve lifter 11 to the right. As a result, the floating valve 6 is pressed by the valve lifter 11 and moves to the right, and a gap is created between the floating valve 6 and the fixed valve seat 9. On the other hand, since compressed air is constantly supplied into the air pipe 16 from the direction of the arrow in FIG. 1, the compressed air blown out from the port 18 sequentially passes through the hollow chamber 19, the above-mentioned gap, and the through holes 27 and 26, and the cylinder body 4 It flows into the pressure chamber 25 on the left side. In this way, pressure is applied to the piston 2a of the piston rod 2, the piston rod 2 follows the operating rod 1 and moves to the right, and the transmission shifts.

When the shift is completed, the switching valve 5 returns to the neutral state, and the compressed air in the pressure chamber 25 passes through the through holes 27 and 26 and the exhaust passage 11 a of the valve lifter 11 and the end surface of the piston rod 2. Released into the atmosphere. When the piston 2a moves to the right, the compressed air in the pressure chamber 24 leaks into the space between the left and right cup packings 30 and 31, causing the lip portion 30a of the right cup packing 30 to pass through the inner peripheral surface of the cylinder body 4. Are pressed against. That is, the piston 2a is sealed only by the cup packing 30 on the right side.

Next, when the change lever is returned to the neutral position from here, the operating rod 1 moves leftward, and its tip pushes the end surface of the slit 21 of the valve lifter 12 to move the valve lifter 12 leftward. . As a result, the floating valve 7 is pressed by the valve lifter 12 to move to the left, and a gap is created between the floating valve 7 and the fixed valve seat 10. Then, the compressed air blown out from the port 18 sequentially flows through the hollow chamber 19, the gap, and the through holes 22 and 23 and flows into the left pressure chamber 25 in the cylinder body 4. In this way, pressure is applied to the piston 2a of the piston rod 2, and the piston rod 2 follows the operation rod 1 and moves left. Immediately before the piston 2a returns to the neutral position, the floating valve 7 separates from the valve lifter 12, and the compressed air in the pressure chamber 24 passes through the through holes 22 and 23 and the exhaust passage 12a of the valve lifter 12 to the outside. Is discharged to.

By the way, the compressed air in the pressure chamber 24 is also discharged through the following path. That is, when the piston 2a returns to the neutral position in this way, the compressed air in the pressure chamber 24 leaks through the right side cup packing 30 into the space S between the left and right cup packings 30 and 31, and the left side The lip portion 31a of the cup packing 31 is pressed against the inner peripheral surface of the cylinder body 4 (see FIG. 5). That is, the piston 2a is sealed only by the cup packing 31 on the left side. When the left cup packing 31 reaches the concave portion 32, the lip portion 31a fits in the concave portion 32 and separates from the bottom surface 32a. Then, the lip portion 30a of the right side cup packing 30 is pushed down by the compressed air, and the compressed air flows into the left side pressure chamber 25 through the recess 32. The inflowing air is discharged into the atmosphere from the end surface of the piston rod through the above-mentioned path. Therefore, even if the change lever is moved in the neutral position by an amount of play and the tip of the valve lifter 12 is pressed against the idle valve 7 to block the exhaust passage 12a, no residual pressure is generated in the right pressure chamber 24. .

By the way, as shown in FIG. 7, even if the two cup packings 34 and 35 are attached to the piston 2a with their lip portions 34a and 35a separated from each other, the same effect can be expected. In this case, a recess 36 having a trapezoidal cross section is formed on the inner peripheral surface of the cylinder body 4 at a position where these cup packings 34, 35 should be in sliding contact with each other at the neutral position, and the recess 36 is formed. A gap may be formed between the bottom surface 36a and the lip portions 34a, 35a of the cup packings 34, 35. Alternatively, instead of the cup packings 34 and 35, an X ring 37 shown in FIG. 8, a cup packing 38 shown in FIG. 9, a packing 39 shown in FIG. 10, or the like may be used. The gap between these packings and the bottom surface 36a of the recess 36 is preferably made as small as possible.

In these embodiments, when the piston 2a is in the neutral position, the left and right pressure chambers 24, 25 communicate with each other through the gap between each packing and the bottom surface 36a of the recess 36. It is possible to prevent the residual pressure from stopping. By the way, even in this case, when the piston 2a is operated from the neutral position, there is no risk that the compressed air leaks to the pressure chamber on the opposite side to hinder the operation. The reason is as follows.

The striker 3 is connected to the shift lever of the transmission device with some play. Therefore, when the operation rod 1 is moved, the piston rod 2 is pulled by the frictional resistance and moved by this play. This is because when the compressed air flows into the pressure chambers 24 and 25, the packing has already left the recess 36 and is in sliding contact with the inner peripheral surface of the cylinder body 4.

[0021]

[Effect of device]

 According to the present invention, when the piston returns to the neutral position, no residual pressure is generated in the pressure chamber in the cylinder, and the select operation can be always performed smoothly.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a booster for operating a transmission according to the present invention.

FIG. 2 is an enlarged view showing a main part of the apparatus.

3 is a cross-sectional view taken along the line AA shown in FIG.

FIG. 4 is an enlarged view showing the inside of a dotted frame B in FIG.

FIG. 5 is a diagram showing a state in which the piston of FIG. 4 returns to a neutral position.

6 is a diagram showing a state in which compressed air leaks from the cup packing of FIG.

FIG. 7 is a diagram showing a modification of FIG.

FIG. 8 is a diagram showing a modification of FIG.

FIG. 9 is a diagram showing a modification of FIG.

FIG. 10 is a diagram showing a modification of FIG.

FIG. 11 is a diagram showing a conventional example corresponding to FIG.

FIG. 12 is a diagram showing a problematic state of a conventional device.

FIG. 13 is an explanatory diagram showing an arrangement of shift jaws of a transmission and shift levers of a transmission device.

[Explanation of symbols]

 1 Operation Rod 2 Piston Rod 2a Piston 3 Strikeer 4 Cylinder Body 5 Switching Valve 6 Floating Valve 7 Floating Valve 11 Valve Lifter 12 Valve Lifter 16 Air Pipe 17 Compressed Air Supply Port 24 Pressure Chamber 25 Pressure Chamber 30 Cup Packing 30a Lip Part 31 Cup Packing 31a Lip portion 32 Recessed portion 32a Bottom surface

Claims (3)

[Scope of utility model registration request] 1. A cylinder body, a hollow piston rod slidably arranged in the cylinder body, an operation rod inserted in the piston rod, and a piston of the piston rod to define the inside of the cylinder body. A switching valve disposed inside the piston rod for selectively supplying compressed air to one of the two pressure chambers, and the operating rod is moved axially within the piston rod to switch the switching valve. In the booster for operating a transmission, wherein compressed air is supplied to one of the pressure chambers to operate the piston rod, and the piston rod follows the movement of the operation rod. Install two cup packings with their lip parts facing each other, and at the same time, on the inner peripheral surface of the cylinder body, the piston When the piston is returned to the neutral position, a lip portion of the cup packing on the front side with respect to the traveling direction of the piston is formed when a recess is formed over the entire circumference between the cup packings in the neutral position. Is fitted into the concave portion and separated from the bottom surface thereof, and the lip portion of the cup packing on the rear side is pushed down by compressed air to separate from the inner peripheral surface of the cylinder body. Force device. 2. A cylinder body, a hollow piston rod slidably arranged in the cylinder body, an operation rod inserted in the piston rod, and a piston of the piston rod to define the inside of the cylinder body. A switching valve disposed inside the piston rod for selectively supplying compressed air to one of the two pressure chambers, and the operating rod is moved axially within the piston rod to switch the switching valve. And a compressed air is supplied to one of the pressure chambers to operate the piston rod so that the piston rod follows the movement of the operation rod. On the inner peripheral surface of the above, a recess is formed over the entire circumference at a position where the packing of the piston should be in sliding contact at the neutral position,
A booster for operating a transmission, characterized in that a gap is formed between the bottom surface of the recess and the packing. 3. The booster for operating a transmission according to claim 1, wherein the lip portions of the two cup packings are in sliding contact with the opening edges of the recesses at the neutral position.