JPS6333022B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission for an automobile, and particularly to a multi-stage transmission equipped with a main transmission and a sub-transmission.
The present invention relates to a transmission that can reduce shift operation force when shifting into gear through the cooperative action of an air valve for switching an auxiliary transmission and a valve opening/closing cam on a shift select shaft.

First, the structure of a conventional multi-speed transmission will be explained. For example, a main transmission with four speed gears and a sub-transmission with two speed change gears, low speed and high speed gears are combined to change the range. Multi-speed transmissions of the type are known from the prior art.

In such a multi-speed transmission, the gears of the main transmission are changed by moving the shift select shaft connected to the change lever in the shift direction and the select direction, and the gears of the auxiliary transmission are changed by moving the shift select shaft connected to the change lever in the shift direction and the select direction. For switching, a valve opening/closing cam installed on the shift select shaft of the main transmission switches a valve that sends fluid to a cylinder installed in the auxiliary transmission to switch the auxiliary transmission to a low-speed gear or a high-speed gear. The two-shift operation is designed to combine the gears of the main transmission and auxiliary transmission to maximize the efficiency of the engine's output.

In addition, the change lever of such a multi-speed transmission has a so-called double H-type shift pattern, in which two normal H-type shift patterns are placed side by side. When the change lever is operated to the 6th speed select position, the shift air valve of the sub-transmission is switched from a low-speed valve to a high-speed valve by a valve opening/closing cam.

In this conventional method, the shift select shaft of the main transmission is rotated by operating a change lever, and when the shift select shaft is in the neutral position, an air valve is operated to select the high speed side or the low speed side of the auxiliary transmission. In such an automobile transmission, in order to protect the synchronizing mechanism of the auxiliary transmission, it is necessary to have a structure that allows air to flow into the air cylinder of the auxiliary transmission only when the shift select shaft of the main transmission is in the neutral position. That is,
When the main transmission is in the neutral position, no driving force is transmitted from the main transmission to the auxiliary transmission.

By switching the auxiliary transmission from a low gear to a high gear or from a high gear to a low gear in such a situation, excessive force is not applied to the synchronization mechanism of the auxiliary transmission, protecting the synchronization mechanism and improving durability. It is necessary to aim for

Also, while the gear of the main transmission is being shifted to any shift position, air should leak from the switching air cylinder of the auxiliary transmission and the air between the air cylinder and the air pressure source will leak. In order to prevent this, it is necessary to temporarily close the air valve and open it only when the main transmission is in the neutral position, allowing air to be sent to the air cylinder.

1 and 2 show the structure of a conventional air valve 1, in which a shift select shaft 2 includes a valve opening/closing cam 3 in which a neutral position detection part is formed as a recess 3b in an outer peripheral part 3a. is fixed, and the neutral position detector 5 of the air valve 1 is depressed into and engaged with the recess 3b to detect the neutral position of the shift select shaft 2. Only in this case, the air cylinder of the sub-transmission It was designed to allow air to flow into the air. When the shift select shaft 2 is rotated to shift, the neutral position detector 5 is pushed up from the recess 3b to the outer circumference 3a, thereby stopping the supply of air to the air cylinder of the sub-transmission. At this time, the spring pressure and air pressure of the compression spring 6 are applied to the neutral position detector 5 from above, and the recess 3b
The frictional force that occurs when the gears escape from the main transmission acts, and the operating force for synchronizing the gears of the main transmission is added to these forces, so the shift force that rotates the shift select shaft 2 becomes extremely large, making it difficult to perform a shift operation. It was difficult to use, and the driver's hands got tired.

Furthermore, the neutral position display device for a transmission mechanism disclosed in Utility Model Application No. 54-81068 uses the shifter of the transmission to detect the neutral position of the transmission, but the neutral position detector is , which is an electric switch that operates with a slight force, does not disclose any idea of reducing the operating force of the shifter by utilizing a cooperative action with an air valve on which a considerably large reaction force acts. Furthermore, the starter safety switch for mobile agricultural machinery disclosed in Japanese Utility Model Publication No. 56-30695 is similar to the conventional example described above, in which a chevron-shaped protrusion provided on the shifter operates a switch contact for detecting the neutral position. Furthermore, the present invention does not disclose the idea of reducing the operating force of the shifter through cooperation with an air valve. In addition, a power shift device for an auxiliary transmission in an automobile disclosed in Japanese Patent Application Laid-Open No. 55-39871 attaches a manual air switching valve to the conventional H-type change lever, and electrically indicates when the main transmission is in neutral. It is detected by a switch, and when the clutch is depressed, air is supplied to the high-speed side or low-speed side air cylinder of the auxiliary transmission by electromagnetic force, and air piping is used. This document does not disclose the idea or structure of using air pressure to reduce the shift operation force when shifting into gear.

The present invention has been made in order to eliminate the drawbacks of the prior art described above, and its purpose is to provide a main transmission, a sub-transmission, and a shift select shaft disposed opposite to a shift select shaft of the main transmission. A pair of neutral position detectors and integrated valve spools are urged against the shift select shaft by a compression spring, and are slidably accommodated in the pair of valve chambers to connect the air pressure source and sub-transmission. an air valve that is connected in communication with the air cylinder and switches the sub-transmission to a low speed side or a high speed side by advancing or retracting the valve spool; A convex part is formed in a part of the shift select shaft to move back one of the pair of neutral position detectors only when the shift select shaft is in the neutral position, and when the shift select shaft is shifted from the neutral position to any gear position, air is removed. A valve opening/closing cam in which the air pressure of the pressure source and the pressing force of the compression spring of the air valve act on the inclined surface of the convex portion via the neutral position detector to generate a torque that rotates the shift select shaft in the gear shifting direction. When the shift select shaft is rotated in the gear shifting direction, the pressing force from the compression spring inside the air valve and the air pressure are used inversely by the cooperation between the air valve and the valve opening/closing cam. The above torque applied from the neutral position detector to the valve opening/closing cam reduces the rotation of the shift select shaft in the gear shifting direction, thereby reducing the shift operation force when shifting gear. The objective is to make shift operations easier and reduce driver's hand fatigue.

In short, the present invention provides a main transmission in which a plurality of gear positions can be selected by rotating and sliding a shift select shaft, and a fork for switching each gear position of the main transmission to a low speed side or a high speed side. A sub-transmission is provided with a piston for driving the main transmission, and an air cylinder in which a low-speed side cylinder chamber and a high-speed side cylinder chamber are formed on both sides of the piston and slidably accommodates the piston; Valve spools arranged opposite to the shift select shaft and each integrated with a pair of neutral position detectors are urged against the shift select shaft by a compression spring and are slidably accommodated in the pair of valve chambers. an air valve that is communicatively connected to an air pressure source and an air cylinder of the auxiliary transmission and switches the auxiliary transmission to a low speed side or a high speed side by advancing or retracting the valve spool; A convex portion is formed on a part of the outer periphery of the shift select shaft so as to be fixed opposite to the neutral position detecting element of the shift select shaft. When a shift operation is performed from the position to any gear position, the air pressure of the air pressure source and the pressing force of the compression spring act on the inclined surface of the convex portion via the neutral position detector to select the shift select. It is characterized by comprising a valve opening/closing cam that generates torque to rotate the shaft in the gear shift direction.

The present invention will be explained below based on embodiments shown in the drawings. The automobile transmission 11 according to the present invention includes a main transmission 12, an air valve 13, a sub-transmission 14, an air cylinder 15, a shift select shaft 16, and a valve opening/closing cam 17, and the shift select shaft 16 has a change lever. (not shown)
When the change lever is moved from the 1st or 2nd gear select position to the 7th or 8th gear select position, the shift select shaft 16 sequentially moves to the left in FIG. It's becoming like that. Further, as shown in FIG. 4, a shift member 20 having two protrusions 20a formed at a constant interval is fixed to the shift select shaft 16. In addition, first, second and third shift heads 2 are arranged opposite to the shift member.
1, 22, and 23 are arranged, and these shift heads have first, second, and third shift head shafts 24, 25, and 25 fitted into the respective shift heads.
26 is moved in a direction perpendicular to the plane of the paper by operating the change lever, and the shift select shaft 16 can be selected or shifted by the cooperative action of these shift members and the shift head. ing.

To be more specific, the multi-stage transmission shown in FIG. The convex portion 20a engages with the shift head 22, and when the change lever is operated to shift to 1st or 2nd gear, the gear is shifted to 2nd gear.
By moving the shift head shaft 25 in a direction perpendicular to the plane of the paper, a shift fork (not shown) fixed to the shift head shaft 25 is moved to engage the first gear or the second gear. ing.

Similarly, in order to shift to third or fourth speed, the shift select lever 16 is moved slightly to the left, and the left protrusion 20a of the shift member 20 is engaged with the shift head 21.

Next, in order to shift to the 5th or 6th speed, the shift select shaft 16 is moved further to the left, and the right protrusion 20a of the shift member 20 is engaged with the shift head 22.

At this time, as will be described later, a valve opening/closing cam 17 fixed to the shift select shaft 16 switches an air valve that switches between low speed and high speed of the auxiliary transmission from the low speed side to the high speed side. As a result, the shift head shaft 25, which normally changes the first or second gear, is configured to change the fifth or sixth gear.

When the shift select shaft 16 is further moved to the left and the right protrusion 20a is engaged with the shift head 21, the shift head shaft 24 is adapted to switch between the 7th and 8th gears.

Note that by moving the shift select shaft 16 to the rightmost side against the spring force, the right protrusion 20a
When the shift head shaft 26 is engaged with the shift head 23 and the shift head shaft 26 is moved perpendicular to the plane of the paper, the gear can be switched to ultra-low or reverse gear.

Next, the structure of the valve opening/closing cam 17, which is a subject of the present invention, will be explained. In FIG. 4, the valve opening/closing cam 17 is fixed on the shift select shaft 16 facing a pair of neutral position detectors 30, and the valve opening/closing cam 17 is fixed on a part of the outer circumference 17b only when the shift select shaft 16 is in the neutral position. A convex portion 17a for retracting one of the neutral position detectors 30 is formed, and the convex portion and the outer circumferential portion 17b are connected by inclined surfaces 17d on both sides. 17c are formed respectively. When the shift select shaft 16 is shifted from the neutral position to any gear position, the air pressure of the air pressure source and the compression spring in the air valve 13, that is, the first compression spring 31
The pressing force of the second compression spring 42 acts on the inclined surface 17d of the convex portion 17a via the neutral position detector 30 to generate a torque that rotates the shift select shaft 16 in the gear shifting direction. has been done. The valve opening/closing cam 17 also moves from the right to the left by the same amount of displacement when the shift select shaft 16 moves from the right side to the left side in FIG. 4 by selecting a change lever (not shown). It's getting old.

When the select position of the change lever is in reverse or ultra-low, 1st, 2nd, 3rd or 4th gear, the valve opening/closing cam 17 moves the neutral position detector 30 on the right side of the air valve 13 to the neutral position. It's starting to push up.

When the change lever is in the 5th, 6th, 7th, or 8th gear select position, the valve opening/closing cam 17 moves to the left in FIG. 4 as the shift select shaft 16 moves. The detector 30 on the left side of the air valve 13 is pushed up and removed from the detector 30 on the right side. That is, when moving from the third or fourth gear select position to the fifth or sixth gear select position, the sub-transmission 14 is switched from a low gear to a high gear.

To explain this point in more detail, the select position of the shift select shaft 16 in FIG. 4 indicates the third or fourth speed select position, and the valve opening/closing cam 17 opens the air valve 13 on the low speed side.
That is, air flows from the first pipe 32 to the air valve 1.
3, passes through the air introduction holes 13a and 13b, and is introduced into the low-speed side cylinder chamber 15a of the air cylinder 15 through the second pipe 33.

As described above, the first function of the valve opening/closing cam 17 is to switch the sub-transmission 14 from a low speed gear to a high speed gear or from a high speed gear to a low speed gear.
Furthermore, as a second important function, air is supplied to the air cylinder 15 only when the main transmission 12 is in the neutral position, and when the main transmission 12 is shifted to any shift position. The air valve 13 is fixed to the valve seat portion 13 by the second compression spring 42.
The valve plate 43, which is biased against e, closes and blocks the flow of air between the air pressure source and the air cylinder 15, in the unlikely event that air leaks from the air cylinder 15, etc. It is also required that the air pressure source is not affected.

The present invention achieves this second function and
The shape of the valve opening/closing cam 17 has been improved to reduce the operating force of the change lever. The axial cross-sectional shape of the shift select shaft 16 of the valve opening/closing cam 17 is as shown in FIG.
It shows the state where it is pushed up and retreated by a. When the shift select shaft 16 rotates to shift into any gear position, the valve opening/closing cam 17 rotates and the neutral position detector 30 is pushed downward, as shown in FIG. When the air valve 13 moves forward, the valve seat 13e of the air valve 13 is closed by the valve plate 43, and the air passage is blocked.

It should be noted that the main transmission 12 is capable of selecting a plurality of gear positions by rotating and sliding a shift select shaft 16. Also, sub-transmission 1
4 includes a piston 35 that drives a fork 37, and a cylinder chamber 15a on the low speed side and a cylinder chamber 15b on the high speed side formed on both sides of the piston, in order to switch the gear position of the main transmission 12 to the low speed side or the high speed side. , and an air cylinder 15 that slidably accommodates a piston 35.

The air valve 13 is arranged to face the shift select shaft 16 of the main transmission 12, and a pair of valve spools 44 each integrated with a pair of neutral position detectors 30 are shifted by the first compression spring 31. The valve plate 43 is pressed against the select shaft 16 and is slidably accommodated in the pair of valve chambers 13f, and the valve plate 43 is pressed against the valve seat portion 13e by the second compression spring 42, and the valve plate 43 is pressed against the valve seat portion 13e by the second compression spring 42. There are two communication holes 13g between the valve chambers 13f.
and 13h are formed, and an exhaust hole 13i is formed concentrically with the communication hole 13h. Then, the air pressure source and the air cylinder 15 of the sub-transmission 14 are connected to the first
The valve spool 44 is connected to the valve spool 44 by a pipe 32, a second pipe 33, and a third pipe 41.
The auxiliary transmission 14 is switched to a low speed side or a high speed side by moving forward or backward.

The valve spool 44 also includes a first piston 4.
4a, the second piston 44b, and the hollow sleeve 4
4c and a neutral position detector 30 are formed, and ventilation holes 44d formed through the hollow sleeve 44c are formed laterally at the upper end 44e of the hollow sleeve 44c and the intermediate point between the first piston 44a and the second piston 44b, respectively. It is open and communicates with the communication hole 13h and the exhaust air 13i.

The present invention is configured as described above, and its operation will be explained below. As shown in FIG. 4, the convex portion 17a of the valve opening/closing cam 17 allows
The right detector 30 of the air valve 13 is pushed up to the uppermost position against the spring pressure of the first compression spring 31 and the second compression spring 42 and retreated, and the valve plate 43 is pushed back by the upper end 44e of the hollow sleeve 44c. is pushed up and the neutral position of the shift select shaft 16 is detected, the first pipe 3
The air flowing into the air valve 13 from 2 passes through the air introduction holes 13a, 13b and the second pipe 33 to the cylinder chamber 15a on the low speed side of the air cylinder 15.
The piston 35 moves in the direction of arrow A, and the low speed side of the sub-transmission 14 is selected via a fork 37 fixed to a piston rod 36 integral with the piston. In this case, the air in the high-speed side cylinder chamber 15b of the air cylinder 15 is pushed out by the piston 35 to the third pipe 41, and from the third pipe to the air introduction hole 13c of the air valve 13 on the left side in FIG. Through the valve chamber 13
f, enters the ventilation hole 44d through the gap between the upper end 44e of the hollow sleeve 44c and the valve plate 43, and is exhausted to the atmosphere through the exhaust hole 13i.

Conversely, when the left detector 30 of the air valve 13 is pushed up by the convex portion 17a of the valve opening/closing cam 17 and the neutral position of the shift select shaft 16 is detected, the first pipe 32
The air flowing into the air valve 13 is introduced into the high-speed side cylinder chamber 15b of the air cylinder 15 through the air introduction hole 13a, the communication hole 13g, the valve chamber 13f, the air introduction hole 13c, and the third pipe 41, and is introduced into the cylinder chamber 15b on the high-speed side of the air cylinder 15. 35 moves in the direction of arrow B, and the high speed side of the sub-transmission 14 is selected via the fork 37. In this case, the air in the cylinder chamber 15a on the low speed side of the air cylinder 15 is pushed out by the piston 35 to the second pipe 33, and from the second pipe to the air introduction hole 13b of the air valve 13 on the right side in FIG. through the valve chamber 13f,
Hollow sleeve 44 of advanced valve spool 44
The air enters the ventilation hole 44d through the gap between the upper end 44e of the valve plate 43 and the valve plate 43, passes through the communication hole 13h, and is exhausted to the atmosphere from the exhaust hole 13i.

In order to shift the shift select shaft 16 at the neutral position shown in FIG. 5, the shift select shaft must be rotated as shown in FIG. 6 (in the direction of arrow C in the figure). At this time, the detector 30 is pressed downward by the spring pressure of the first compression spring 31 and the second compression spring 42 and air pressure, and the detector 30 is pressed downward by the spring pressure of the first compression spring 31 and the second compression spring 42 and the convex portion 17a of the valve opening/closing cam 17. Since the inclined surface 17d is pushed forward in the shift operation direction (arrow C direction) and torque is generated in the gear shift direction, the shift force of the shift select shaft 16 when the gear is engaged is reduced, and the shift operation force is reduced. Since the shift lever is extremely small, it is possible to shift with a light change lever operation, reducing the driver's hand fatigue.

Furthermore, when switching the shift select shaft 16 from the shifted state shown in FIG. 6 to the neutral position shown in FIG. The detector 30 is simply moved backward against the spring pressure of the first compression spring 31 and the second compression spring 42, and since the shift operation force for removing the gear is originally much smaller than when shifting the gear, the shift select shaft There is no risk that the force for removing the gear 16 will increase and cause a problem.

As described above, the present invention provides a main transmission, a sub-transmission, and a valve spool disposed facing the shift select shaft of the main transmission and each integrated with a pair of neutral position detectors, each of which is moved by a compression spring. The valve spool is pressed against the shift select shaft, is slidably accommodated in a pair of valve chambers, and is communicatively connected to an air pressure source and an air cylinder of the auxiliary transmission, so that the auxiliary transmission is activated by advancing or retracting the valve spool. An air valve that switches to the low speed side or the high speed side, and an air valve that is fixed on the shift select shaft opposite to the pair of neutral position detectors, and a part of the outer periphery of the shift select shaft that is fixed to either of the pair of neutral position detectors only when the shift select shaft is in the neutral position. When the shift select shaft is shifted from the neutral position to any gear position, the air pressure of the air pressure source and the pressing force of the compression spring of the air valve are applied via the neutral position detector. and a valve opening/closing cam that acts on the inclined surface of the convex portion to generate a torque that rotates the shift select shaft in the gear shift direction. Through the cooperative action of the air valve and the valve opening/closing cam, the above torque acting on the valve opening/closing cam from the neutral position detector reversely utilizes the pressing force of the compression spring inside the air valve and the air pressure to shift the shift select shaft into gear. It has the effect of making the rotation in the shift direction lighter and reducing the shift operation force when shifting into gear, thereby making the shift operation easier and reducing driver's hand fatigue. There is an effect that can be done.

[Brief explanation of the drawing]

1 and 2 relate to a conventional example, in which FIG. 1 is a longitudinal cross-sectional view showing the relationship between the air valve and the valve opening/closing cam at the neutral position of the shift select shaft, and FIG. 1, and FIGS. 3 to 6 relate to embodiments of the present invention. FIG. 3 is a front view schematically showing an automotive transmission in partial vertical sectional view, and FIG. 4 is a longitudinal sectional view similar to FIG. 5 is a cross-sectional view showing the mutual relationship between the air valve, the shift select shaft, and the valve opening/closing cam; FIG. 5 is a longitudinal sectional view showing the relationship between the air valve and the valve opening/closing cam at the neutral position of the shift select shaft; FIG. 6 is the shift select shaft. FIG. 6 is a longitudinal sectional view similar to FIG. 5 in the shift position of the shaft; 11 is an automobile transmission, 12 is a main transmission, 1
3 is an air valve, 13f is a valve chamber, 14 is a sub-transmission, 15 is an air cylinder, 15a is a low speed side cylinder chamber, 15b is a high speed side cylinder chamber, 16 is a shift select shaft, 17 is a valve opening/closing cam, 17a is a A convex portion, 17b is an outer peripheral portion, 17d is an inclined surface, 30 is a neutral position detector, 31 is a first compression spring, 37 is a fork, 42 is a second compression spring,
44 is a valve spool.

Claims (1)

[Claims] 1. A main transmission in which multiple gear positions can be selected by rotating and sliding a shift select shaft, and a piston that drives a fork to switch each gear position of the main transmission to a low speed side or a high speed side. and an air cylinder in which a low speed side cylinder chamber and a high speed side cylinder chamber are formed on both sides of the piston and slidably accommodates the piston;
Valve spools, which are disposed opposite to the shift select shaft of the main transmission and are each integrated with a pair of neutral position detectors, are urged against the shift select shaft by a compression spring to open a pair of valve chambers. an air valve that is slidably housed in and connected to an air pressure source and an air cylinder of the auxiliary transmission to switch the auxiliary transmission to a low speed side or a high speed side by advancing or retracting the valve spool; A convex portion is formed on a part of the outer periphery of the shift select shaft, and is fixed on the select shaft so as to face the pair of neutral position detectors. When the shift select shaft is shifted from the neutral position to any gear position, the air pressure of the air pressure source and the pressing force of the compression spring are applied to the inclined surface of the convex portion via the neutral position detector. 1. A transmission for an automobile, comprising: a valve opening/closing cam that acts to generate a torque that rotates the shift select shaft in a gear shifting direction.