JPH0722517Y2 - Locking device for V-belt type automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a V-belt type automatic transmission in which a movable sheave moves toward a high speed range due to an increase in engine speed.

(Prior Art) FIG. 9 shows an example of a known V-belt type automatic transmission, and the outline of the entire V-belt type automatic transmission will be described first with reference to FIG. The drive shaft 2 and the driven shaft 3 of the transmission are arranged in parallel with each other inside the transmission case 4 and the cover 5, the drive shaft 2 is fixed to the crankshaft 1 of the engine, and the driven shaft 3 is inside the mission case 8. It extends and is interlocked with the drive wheels of the vehicle via the transmission 20 and the like. Further, as shown in FIG. 10, the oil pump 7 for driving the PTO is from the crankshaft 1 to the idler shaft 19 in the crankcase.
It is designed to be driven via gears such as.

A fixed sheave 14 is fixed to the engine side of the driving shaft 2 in FIG. 9, and a movable sheave 15 axially opposed to the fixed sheave 14 is axially movably fitted thereto. Inside the movable sheave 15, a spider 13 that is spline-fitted to the driving shaft 2 is arranged. A biasing spring 16 is contracted between the spider 13 and the movable sheave 15, and the biasing spring 16 causes the movable sheave 13 to move. 15 is a fixed sheave
It is urged toward the low speed range (the side opposite to the arrow A direction side) away from 14. Movable sheave 15 and spider 13
Is engaged by the centrifugal cam mechanism 18 so as to rotate integrally, and is moved to the high speed range side (arrow A side) as the engine speed increases.

A movable sheave 23 is axially movably fitted to the driven shaft 3 in the direction of arrow A, and a fixed sheave 22 is arranged opposite to the movable sheave 23. The action of the torsion coil spring 24 and the cam 25 causes the movable sheave 23 to move. It is urged to the low speed range side (the side opposite to the arrow A direction).

When the engine speed increases with a constant load, the drive-side movable sheave 15 moves in the A direction by the centrifugal cam mechanism 18,
As a result, the driving-side effective radius of the belt 28 is expanded, and at the same time, the driven-side movable sheave 23 moves in the A direction side, thereby reducing the driven-side effective radius of the belt 28. Therefore, the gear ratio shifts to the high speed range side, and the vehicle speed becomes faster.

However, a working vehicle equipped with such an automatic transmission cannot meet the demand for increasing the engine speed and keeping the vehicle speed low.

When the PTO oil pump 7 is operated while the vehicle is traveling at a low speed on a chemical spraying vehicle to spray the chemicals, or when the wagon or work machine is towed or climbed, the engine speed is increased in response to an increase in load. It is necessary to increase the number and run at a constant low speed, but this cannot be accommodated. As a prior art, there is Jikkou Sho 57-29105.

(Object of the Invention) The object of the present invention is to allow the driven movable sheave to be locked in the V-belt type automatic transmission when necessary, so that the vehicle can run at a constant low speed while increasing the engine speed. In this way, it is possible to perform each of the above operations.

(Technical means for achieving the object) In order to achieve the above object, the device according to claim 1 of the present application,
A V-belt type automatic transmission in which the movable sheave moves axially toward the high speed range due to an increase in engine speed,
In a lock device for a V-belt type automatic transmission, which includes a lock member that is freely changeable between a lock position that restricts movement of the movable sheave toward the high speed range and a release position that allows movement of the movable sheave toward the high speed range, A shaft core hole and a lock member insertion hole that is perpendicular to the shaft core hole are formed in the driven shaft, and a lock pin is inserted into the insertion hole as a lock member. It is movable to a lock position that restricts movement to the range side and a release position where it is pulled into the insertion hole, and is urged to the release position by a return spring so that it can move axially in the shaft core hole. An operated push rod is inserted, a wedge surface is formed on the push rod, and the wedge surface is in contact with the lock pin.

According to a second aspect of the present invention, in order to improve the durability of the lock member, a shaft core hole and a plurality of lock member insertion holes perpendicular to the shaft hole are formed in the driven shaft, and each insertion hole has a spherical end. -Shaped lock members are respectively inserted, and recesses that can be engaged with the lock members are formed in the inner peripheral portion of the movable sheave, and the lock members engage with the recesses to extend toward the high-speed range side of the movable sheave. A push position that is movable between a lock position that restricts movement and a release position that retracts into the insertion hole, and a push rod that is movably operated in the axial direction is inserted into the axial core hole. The movement of the push rod forms a tapered surface that abuts on each lock member and pushes it toward the lock position.

According to a third aspect of the present invention, a stepped engaging portion that is engageable with the lock member at the lock position is axially spaced from the movable sheave so that it can be selectively set to two or more gear shift range positions. A plurality of movable sheaves are formed on the side of
It is designed so that it can be selectively locked at more than one range position.

(Embodiment) FIG. 1 is a lock device according to claim 1, which is an enlarged vertical cross-sectional view of a driven side of a V-belt type automatic transmission having a pin or the like as a lock member. Since the structure is the same as that shown in FIG. 9, the illustration of the driving shaft and the structure description will be omitted.

The driven-side fixed sheave 22 integrally has a tubular portion 22a extending rearward, a disk-shaped housing 31 is fixed to the rear end portion of the tubular portion 22a, and an inner peripheral end portion of the housing 31 has a ring 36 and a nut 37.
Is fixed to the driven shaft 3 so as not to move in the axial direction, and is fixed to the rear end flange 32 of the sleeve 33.
The sleeve 33 has spline teeth on the inner circumference, and is spline-fitted to the outer spline teeth of the driven shaft 3.

The movable sheave 23 is arranged on the front side of the fixed sheave, and integrally has an inner peripheral boss 23a extending rearward. The boss 23a
A torque cam 25 is spline-fitted to the outer peripheral surface of the rear part, and the cam 25 is locked by a snap ring 40 so as not to move backward, and the pin-shaped shoe 35 of the fixed sheave 22 is fixed to the front end wavy cam surface 25a of the cam 25. Are in contact. On the other hand, a torsion spring 24 is interposed between the cam 25 and the fixed sheave 22, and urges the movable sheave 23 in the rotational direction to move the shoe 35 to the cam surface 25a.
It is held on the low speed range side (opposite to the direction of arrow A) by being located in the valley portion. That is, when the movable sheave 23 twists in the rotational direction against the fixed sheave 22 against the torsion spring 24, the movable sheave 23 is pushed and moved in the arrow A direction.

The lock device, which is the main part of the present invention, will be described. A shaft core hole 38 that is long in the axial direction is formed in the shaft core portion of the driven shaft 3, and the front end portion of the shaft core hole 38 is closed and the rear end portion is open. A lock member insertion hole 39 is formed in the front portion of the shaft core hole 38 so as to penetrate the driven shaft 3 in a direction perpendicular to the shaft center, and the rear end of the insertion hole 39 is located at the low speed range position in FIG. The movable sheave 23 is formed so as to come to a position substantially corresponding to the front edge. One round bar-shaped lock pin 42 is inserted into the lock member insertion hole 39, and as shown in FIG. 3, a lock position protruding radially outward from the outer peripheral surface of the driven shaft 3 and a lock position shown in FIG. It is freely movable to the release position where it is pulled into the insertion hole 39.

A return spring 43 is contracted between the flange portion 42a on the inner side of the lock pin 42 and the inner peripheral step portion of the insertion hole 39, and the lock pin 42 is pulled into the hole by the return spring 43. It is biased to the release position.

A push rod 41 is inserted into the shaft hole 38 so as to be movable in the axial direction, and a wedge surface 41a is formed at the front end of the push rod 41 by cutting off the surface on the lock pin side in an inclined manner. The wedge surface 41a is in contact with the inclined cutout surface 42b formed in the collar portion 42a of the lock pin 42.

The rear end portion of the push rod 41 projects rearward from the shaft core hole 38, and a return spring 48 is provided between the snap ring 47 fitted to the rear portion of the push rod 41 and the rear inner peripheral step portion of the driven shaft 3.
Is compressed, and the return spring 48 pushes the push rod 41
Is biased to the rear.

A cylindrical piston case 54 is fitted to the rear end of the driven shaft 3, and the piston case 54 is fixed to the driven shaft 3 by a cap nut 45 screwed to the outer peripheral thread portion of the nut 37. A piston 55 is axially movably fitted in the piston case 54, a rear end portion of the push rod 41 is fitted in a front end concave portion of the piston 55, and a steel ball 56 is fitted in a rear end concave portion,
The steel ball 56 is in contact with the front end edge of the auxiliary rod 57 on the rear side. The auxiliary rod 57 is fitted and supported on the rear wall of the piston case 54 so as to be movable in the axial direction, extends rearward, and is retained by a locking ring 53 at the front end.

A rotating shaft 63 is rotatably supported by the cap 5a of the transmission case cover 5 for pressing the auxiliary rod 57, and a holding arm 61 and an operating lever 66 are fixed to the rotating shaft 63. The pressing arm 61 is rotatably supported by a pressing roller 60 that contacts the rear end of the auxiliary rod 57. An operation cable 70 is connected to the tip of the operation lever 66, and the operation cable 70 passes through a cable holder 68 and is interlocked with an appropriate operation mechanism.

In FIG. 2 showing a view taken along the arrow II in FIG. 1, the rotating shaft 63 is fitted to the boss 65 supported by the cover cap 5a, and
The pressing roller 60 is urged by the torsion spring 69 so as to come to the rear, and by pulling the cable 70, the pressing roller 60 in FIG. 1 moves forward and pushes the auxiliary rod 57 forward. There is.

The operation will be described. First when the cable 70 is not pulled
As shown in the figure, the push rod 41 stands by at the rear position by the return spring 48, and the lock pin 42 is retracted into the insertion hole 39 to the release position.

When the engine is operated in this state, the drive-side movable sheave 15 shown in FIG. 9 moves in the direction of arrow A and the effective diameter increases as the engine speed increases when the load is constant. The driven-side movable sheave 23 moves in the direction of arrow A to reduce the effective diameter. That is, the gear ratio changes to the high speed range side.

When the engine speed is increased to increase the load and the vehicle travels at a constant low speed, for example, the PTO oil pump 7
When driving while operating an implement such as a spreader using the, when pulling or climbing the work implement, pull the operation cable 70 to lock the driven movable sheave 23 at the low speed range position. To do.

That is, when the operation cable 70 shown in FIG. 1 is pulled, the presser arm 61 rotates forward in FIG. 1 via the operation lever 66 and the rotating shaft 63, and the presser roller 60 pushes the auxiliary rod 57 forward. The push rod 41 moves forward through the steel ball 56 and the piston 55 and against the return spring 48, and the front end wedge surface 41a.
The inner cutout surface 42b of the lock pin 42 is pushed by. As a result, as shown in FIG. 3, the lock pin 42 projects radially outward to the lock position against the return spring 43. The lock pin 42 at the lock position contacts the front end edge of the movable sheave 23 and restricts movement toward the high speed range (arrow A side), so that the gear ratio is maintained at a constant low speed range.

(Another embodiment) (1) FIG. 4 shows a locking device provided with the spherical tip member according to claim 2 as a locking member, and the inner peripheral surface of the boss 23a of the driven movable sheave 23 is A sleeve 73, which is a component of the movable sheave 23, is fixed, and an annular recess 74 is formed in the axially intermediate portion of the sleeve 73. On the other hand, the driven shaft 3 has two or more lock member insertion holes 39 formed in the same cross section perpendicular to the axis, and a steel ball 71 as a lock member is movable in the radial direction in each insertion hole 39. Two are fitted in each. The axial position of each insertion hole 39 is a certain distance behind the front end edge of the movable sheave 23, and is formed at a position corresponding to the annular recess 74 of the sleeve 73 during the low speed range.

A taper surface 41b is formed at the front end of the push rod 41 so that it can abut the steel ball 71.

The structure of the rear end portion of the push rod 41 is similar to the structure shown in FIG.

When unlocked, the push rod 41 is retracted rearward as shown in FIG. 4, and the movable sheave 23 is on the high speed range side (arrow A).
Side) can be moved. While the engine is rotating, the steel balls 71 move outward in the radial direction by the centrifugal force, but since the centrifugal force itself is small, the sleeve 73 moves in the direction of arrow A while pushing the steel balls 71 inward.

When the push rod 41 is moved forward by the operating mechanism during the low speed range, each steel ball 71 is pushed outward in the radial direction by the tapered surface 41b and engages with the annular recess 74 to the high speed range side of the movable sheave 23. Regulate the movement of. As a result, the gear ratio can be maintained in a constant low speed range even if the engine speed is increased.

(2) FIG. 5 is another example of the device according to claim 2, instead of inserting two steel balls into each of the plurality of insertion holes 39,
Long lock members 77 having both ends formed in a spherical shape are inserted.

(3) The cross-sectional shape of each annular recess 74 in FIGS. 4 and 5 may be an arc shape corresponding to the spherical surface of the lock member.

(4) As an operation mechanism to be connected to the cable 70 of FIG. 1, a manual lever for locking may be simply connected, or PT
O It may be possible to interlock with the operating lever of the work equipment so that the PTO work equipment can be locked at the same time when the operation is started.

(5) FIGS. 6 to 8 show a lock device to which the invention according to claim 3 is applied and which can set two or more gear ratios. A sleeve 73, which is a constituent member of the movable sheave 23, is fixed to the inner peripheral surface of the boss 23a of the movable sheave 23.
A large-diameter annular recess 74 is formed in the axially intermediate portion of the, and a small-diameter annular recess 75 is formed on the rear side of this through a step-like engaging portion 74a. Is a stepped engagement part
It is connected to the inner peripheral surface of the sleeve 73 via 75a. Both the step-like engaging portions 75a, 75b are spaced from each other in the axial direction, and are each formed in a tapered surface whose diameter increases toward the front.

On the other hand, the driven shaft 3 has two or more lock member insertion holes 39 formed in the same cross section perpendicular to the shaft center.
A lock pin 77 as a lock member is fitted therein so as to be movable in the radial direction, and the front and rear of the outer peripheral edge of the lock pin 77 are each cut in a tapered shape.

The axial position of the insertion hole 39 is a certain distance behind the front end edge of the movable sheave 23, and is formed at a position corresponding to the large-diameter annular recess 74 of the sleeve 73 during the low speed range.

A large-diameter taper surface 41b that can come into contact with the lock pin 77 is formed at the front end portion of the push rod 41, and a small-diameter taper surface 41c is further formed in front of it.

The structure of the rear end of the push rod 41 is almost the same as the structure of FIG. 1, but the piston 55 and the steel ball 56 of FIG. 1 are omitted, and the rear end of the push rod 57 is directly held by the pressing arm 61.
Is in contact with the spherical surface of the tip.

The operation will be described. When unlocked, the push rod 41 is retracted rearward as shown in FIG. 6, and the lock pin 77 is in a state of being movable toward the axial center. Therefore, the movable sheave 23 pushes the lock pin 77 toward the shaft core side by the tapered stepped engaging portion 74a and the stepped engaging portion 75a, and the high speed range side (arrow A).
Side) can be moved.

FIG. 7 shows a state in which the lock is performed at the intermediate speed range position. When the push rod 41 is moved forward by a certain distance by the operating mechanism, the small-diameter tapered surface 41c pushes the lock pin 77 radially outward. The push pin 41 with the lock pin 77 in contact with the large-diameter tapered surface 41b.
Has been stopped. In this state, the movable sheave 23 can be moved to the high speed range side by pushing the lock pin 77 toward the shaft core side by the large diameter stepped engaging portion 74a, but the small diameter stepped engaging portion 75a is moved to the lock pin 77. Is locked at an intermediate speed position where it abuts against. Therefore, even if the engine speed is increased, the gear ratio is maintained in the intermediate speed range.

FIG. 8 shows the locked state at the low speed range position. By moving the push rod 41 further forward than the state shown in FIG. 7 by the operating mechanism, the large diameter tapered surface 41b further locks the lock pin 77. The push rod 41 is pushed outward in the radial direction to stop the push rod 41 while the lock pin 77 has passed over the large-diameter tapered surface 41b. In this state, the lock pin 77 projects radially outward from the diameter of the small-diameter recess 75 and fits into the large-diameter recess 74, and the large-diameter engaging portion 74a engages with the lock pin 77, whereby the movable sheave is moved. 23 is locked in the low range position. Therefore, the gear ratio is maintained in the low speed range even if the engine speed is increased.

In the state shown in FIG. 7 or 8, the movable sheave on the driving side also stops at a position according to the circumferential length of the belt,
Gear shifting is restricted by the position of the rod 41.

Although FIGS. 6 to 8 show examples of two speed ratios, the number of stepped engaging portions 74a and 75a of the sleeve 73 and the rod 41 are shown.
It is also possible to secure a gear ratio of three stages or more by sequentially increasing the tapered surfaces 41b and 41c.

(Effects of the Invention) As described above, according to the inventions of claims 1 to 3, the lock is provided in the V-belt type automatic transmission in which the movable sheave moves axially toward the high speed range due to an increase in the engine speed. Since the driven sheave on the driven side can be locked by the device to the low speed range side, it is possible to increase the load when traveling while driving the implement such as a spreader, when towing the work machine or when climbing a slope. On the other hand, the engine speed can be increased and the vehicle can run at a constant low speed.

According to the first and second aspects of the invention, since the lock member and the push rod are built in the driven shaft, it is possible to prevent the transmission from increasing in size.

In addition to the above effects, the invention according to claim 2 has the following effects.

(1) Wear resistance and durability are improved by providing two or more lock members so that the driven-side movable sheave can be locked at two or more places, and by making both ends of the lock member spherical. .

(2) Since the tip end portion of the push rod is formed into a tapered surface, the tapered surface can be formed at the same time when the push rod is manufactured, and the push rod can be easily processed.

(3) Since the recesses engageable with the lock members are formed on the inner peripheral portion of the movable sheave, and the lock members are engaged with the recesses, for example, the front end edge of the movable sheave is locked. Compared to the case, the bending moment applied to the driven shaft when locked is smaller.

Further, according to the invention as set forth in claim 3, since the gear ratio that can be locked can be set to a plurality of stages, for example, when the PTO oil pump 7 is operated and the medicine is sprayed while traveling at a low speed in a chemical spraying vehicle or the like, a wagon is used. When towing or climbing a work implement or the like, it is possible to perform a constant speed running work by selecting a running speed according to various work implements.
It is practical.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a driven side portion of a V-belt type automatic transmission equipped with a lock device according to claim 1 of the present application, and FIG.
Fig. 2 is a partial view as seen from the direction of arrow II, Fig. 3 is an enlarged vertical sectional view of a lock pin portion at the time of locking, and Fig. 4 and Fig. 5 are claims respectively.
6 is a sectional view of the lock device described in claim 3, FIG. 6 is a cross-sectional view of the lock device described in claim 3, and FIGS. 7 and 8 show the lock state at each range position of the lock device shown in FIG. FIG. 9 is an enlarged vertical cross-sectional view, FIG. 9 is an overall vertical cross-sectional view of a conventional V-belt type automatic transmission, and FIG. 10 is a vertical cross-sectional view of the oil point for PTO of FIG. 2 ... Drive shaft, 3 ... Drive shaft, 14 ... Drive side fixed sheave, 15 ... Drive side movable sheave, 22
... Driven side fixed sheave, 23 ... Driven side movable sheave, 38 ... Shaft core hole, 39 ... Lock member insertion hole, 41 ... Push rod, 41a
... Wedge surface, 41b, 41c ... Tapered surface, 42 ... Lock pin (an example of lock member), 43 ... Return spring, 71 ... Steel ball (an example of lock member), 74, 75 ... Recess, 74a, 75a ... Engagement Department, 77
... Lock pin (an example of lock member)

Claims (3)

[Scope of utility model registration request] 1. A V-belt type automatic transmission in which a movable sheave moves axially toward a high speed range due to an increase in engine speed, and a lock position for restricting movement of the movable sheave toward the high speed range, In a locking device of a V-belt type automatic transmission having a lock member that can be changed to a release position that allows the movable sheave to move to the high speed range side, in a driven shaft, a shaft core hole and a lock member insertion hole perpendicular to the shaft hole A lock pin is inserted into the insertion hole as a lock member, and the lock pin protrudes outward in the radial direction and restricts the movement of the movable sheave toward the high speed range. A push rod that is movable to the retracted position and is biased to the released position by the return spring and that is movably operated in the axial direction is inserted into the axial center hole, and the push rod is fitted with a wedge. Forming a surface, locking device of the V-belt type automatic transmission, characterized in that the wedge surface in contact with the locking pin. 2. A V-belt type automatic transmission in which a movable sheave moves axially toward a high speed range due to an increase in engine speed, and a lock position for restricting movement of the movable sheave toward the high speed range, In a locking device for a V-belt type automatic transmission having a lock member that can be changed to a release position that allows the movable sheave to move toward the high speed range side, in a driven shaft, a shaft core hole and a plurality of lock members perpendicular to the shaft hole. Forming an insertion hole,
Locking members having spherical surfaces at both ends are inserted into the respective insertion holes, and recesses are formed on the inner peripheral portion of the movable sheave so as to be engageable with the lock members. The lock members engage with the recesses. Is movable to a lock position for restricting the movement of the movable sheave toward the high speed range side and a release position for retracting the movable sheave into the insertion hole. A lock device for a V-belt type automatic transmission, characterized in that the push rod is formed with a tapered surface which abuts on each lock member and pushes the push rod toward a lock position side when the push rod is moved. 3. A V-belt type automatic transmission in which a movable sheave moves axially toward a high speed range due to an increase in engine speed, and a lock position for restricting movement of the movable sheave toward the high speed range, In a locking device for a V-belt type automatic transmission having a lock member that can be changed to a release position that allows the movable sheave to move toward the high speed range, a stepped engaging portion that can be engaged with the lock member at the lock position is provided. , V-belt type automatic transmission characterized in that a plurality of movable sheaves are formed at intervals in the axial direction, and the movable sheaves can be selectively locked at two or more range positions within the automatic transmission range. Locking device of machine.